Control of Emissions of Air Pollution From Locomotive Engines and Marine Compression-Ignition Engines Less Than 30 Liters per Cylinder

PDF Version (50 pp, 1,316K, About PDF)

[Federal Register: May 6, 2008 (Volume 73, Number 88)]
[Rules and Regulations]
[Page 25297-25346]
From the Federal Register Online via GPO Access [wais.access.gpo.gov]
[DOCID:fr06my08-19]

[[pp. 25297-25346]]
Control of Emissions of Air Pollution From Locomotive Engines and
Marine Compression-Ignition Engines Less Than 30 Liters per Cylinder

[[Continued from page 25296]]

[[Page 25297]]

    (3) For removing background PM, we recommend that you filter all
dilution air, including primary full-flow dilution air, with high-
efficiency particulate air (HEPA) filters that have an initial minimum
collection efficiency specification of 99.97% (see Sec.  1065.1001 for
procedures related to HEPA-filtration efficiencies). Ensure that HEPA
filters are installed properly so that background PM does not leak past
the HEPA filters. If you choose to correct for background PM without
using HEPA filtration, demonstrate that the background PM in the
dilution air contributes less than 50% to the net PM collected on the
sample filter. You may correct net PM without restriction if you use
HEPA filtration.
    (c) Full-flow dilution; constant-volume sampling (CVS). You may
dilute the full flow of raw exhaust in a dilution tunnel that maintains
a nominally constant volume flow rate, molar flow rate or mass flow
rate of diluted exhaust, as follows:
    (1) Construction. Use a tunnel with inside surfaces of 300 series
stainless steel. Electrically ground the entire dilution tunnel. We
recommend a thin-walled and insulated dilution tunnel to minimize
temperature differences between the wall and the exhaust gases.
    (2) Pressure control. Maintain static pressure at the location
where raw exhaust is introduced into the tunnel within &plusmn; 1.2
kPa of atmospheric pressure. You may use a booster blower to control
this pressure. If you test an engine using more careful pressure
control and you show by engineering analysis or by test data that you
require this level of control to demonstrate compliance at the
applicable standards, we will maintain the same level of static
pressure control when we test that engine.
    (3) Mixing. Introduce raw exhaust into the tunnel by directing it
downstream along the centerline of the tunnel. You may introduce a
fraction of dilution air radially from the tunnel's inner surface to
minimize exhaust interaction with the tunnel walls. You may configure
the system with turbulence generators such as orifice plates or fins to
achieve good mixing. We recommend a minimum Reynolds number, Re#, of
4000 for the diluted exhaust stream, where Re# is based on the
inside diameter of the dilution tunnel. Re# is defined in Sec.  1065.640.
    (4) Flow measurement preconditioning. You may condition the diluted
exhaust before measuring its flow rate, as long as this conditioning
takes place downstream of any heated HC or PM sample probes, as follows:
    (i) You may use flow straighteners, pulsation dampeners, or both of
these.
    (ii) You may use a filter.
    (iii) You may use a heat exchanger to control the temperature
upstream of any flow meter, but you must take steps to prevent aqueous
condensation as described in paragraph (c)(6) of this section.
    (5) Flow measurement. Section 1065.240 describes measurement
instruments for diluted exhaust flow.
    (6) Aqueous condensation. To ensure that you measure a flow that
corresponds to a measured concentration, you may either prevent aqueous
condensation between the sample probe location and the flow meter inlet
in the dilution tunnel or you may allow aqueous condensation to occur
and then measure humidity at the flow meter inlet. You may heat or
insulate the dilution tunnel walls, as well as the bulk stream tubing
downstream of the tunnel to prevent aqueous condensation. Calculations
in Sec.  1065.645 and Sec.  1065.650 account for either method of
addressing humidity in the diluted exhaust. Note that preventing
aqueous condensation involves more than keeping pure water in a vapor
phase (see Sec.  1065.1001).
    (7) Flow compensation. Maintain nominally constant molar,
volumetric or mass flow of diluted exhaust. You may maintain nominally
constant flow by either maintaining the temperature and pressure at the
flow meter or by directly controlling the flow of diluted exhaust. You
may also directly control the flow of proportional samplers to maintain
proportional sampling. For an individual test, validate proportional
sampling as described in Sec.  1065.545.
    (d) Partial-flow dilution (PFD). Except as specified in this
paragraph (d), you may dilute a partial flow of raw or previously
diluted exhaust before measuring emissions. Sec.  1065.240 describes
PFD-related flow measurement instruments. PFD may consist of constant
or varying dilution ratios as described in paragraphs (d)(2) and (3) of
this section. An example of a constant dilution ratio PFD is a
``secondary dilution PM'' measurement system.
    (1) Applicability. (i) You may not use PFD if the standard-setting
part prohibits it.
    (ii) You may use PFD to extract a proportional raw exhaust sample
for any batch or continuous PM emission sampling over any transient
duty cycle only if we have explicitly approved it according to Sec. 
1065.10 as an alternative procedure to the specified procedure for
full-flow CVS.
    (iii) You may use PFD to extract a proportional raw exhaust sample
for any batch or continuous gaseous emission sampling.
    (iv) You may use PFD to extract a proportional raw exhaust sample
for any batch or continuous PM emission sampling over any steady-state
duty cycle or its ramped-modal cycle (RMC) equivalent.
    (v) You may use PFD to extract a proportional raw exhaust sample
for any batch or continuous field-testing.
    (vi) You may use PFD to extract a proportional diluted exhaust
sample from a CVS for any batch or continuous emission sampling.
    (vii) You may use PFD to extract a constant raw or diluted exhaust
sample for any continuous emission sampling.
    (2) Constant dilution-ratio PFD. Do one of the following for
constant dilution-ratio PFD:
    (i) Dilute an already proportional flow. For example, you may do
this as a way of performing secondary dilution from a CVS tunnel to
achieve overall dilution ratio for PM sampling.
    (ii) Continuously measure constituent concentrations. For example,
you might dilute to precondition a sample of raw exhaust to control its
temperature, humidity, or constituent concentrations upstream of
continuous analyzers. In this case, you must take into account the
dilution ratio before multiplying the continuous concentration by the
sampled exhaust flow rate.
    (iii) Extract a proportional sample from a separate constant
dilution ratio PFD system. For example, you might use a variable-flow
pump to proportionally fill a gaseous storage medium such as a bag from
a PFD system. In this case, the proportional sampling must meet the
same specifications as varying dilution ratio PFD in paragraph (d)(3)
of this section.
    (iv) For each mode of a discrete-mode test (such as a locomotive
notch setting or a specific setting for speed and torque), use a
constant dilution ratio for any PM sampling. You must change the
overall PM sampling system dilution ratio between modes so that the
dilution ratio on the mode with the highest exhaust flow rate meets
Sec.  1065.140(e)(2) and the dilution ratios on all other modes is
higher than this (minimum) dilution ratio by the ratio of the maximum
exhaust flow rate to the exhaust flow rate of the corresponding other
mode. This is the same dilution ratio requirement for RMC or field
transient testing. You must account for this change in dilution ratio
in your emission calculations.

[[Page 25298]]

    (3) Varying dilution-ratio PFD. All the following provisions apply
for varying dilution-ratio PFD:
    (i) Use a control system with sensors and actuators that can
maintain proportional sampling over intervals as short as 200 ms (i.e.,
5 Hz control).
    (ii) For control input, you may use any sensor output from one or
more measurements; for example, intake-air flow, fuel flow, exhaust
flow, engine speed, and intake manifold temperature and pressure.
    (iii) Account for any emission transit time in the PFD system, as
necessary.
    (iv) You may use preprogrammed data if they have been determined
for the specific test site, duty cycle, and test engine from which you
dilute emissions.
    (v) We recommend that you run practice cycles to meet the
validation criteria in Sec.  1065.545. Note that you must validate
every emission test by meeting the validation criteria with the data
from that specific test. Data from previously validated practice cycles
or other tests may not be used to validate a different emission test.
    (vi) You may not use a PFD system that requires preparatory tuning
or calibration with a CVS or with the emission results from a CVS.
Rather, you must be able to independently calibrate the PFD.
    (e) Dilution air temperature, dilution ratio, residence time, and
temperature control of PM samples. Dilute PM samples at least once
upstream of transfer lines. You may dilute PM samples upstream of a
transfer line using full-flow dilution, or partial-flow dilution
immediately downstream of a PM probe. In the case of partial-flow
dilution, you may have up to 26 cm of insulated length between the end
of the probe and the dilution stage, but we recommend that the length
be as short as practical. Configure dilution systems as follows:
    (1) Set the diluent (i.e., dilution air) temperature to (25  5)
[deg]C. Use good engineering judgment to select a location to
measure this temperature. We recommend that you measure this
temperature as close as practical upstream of the point where diluent
mixes with raw exhaust.
    (2) For any PM dilution system (i.e., CVS or PFD), dilute raw
exhaust with diluent such that the minimum overall ratio of diluted
exhaust to raw exhaust is within the range of (5:1-7:1) and is at least
2:1 for any primary dilution stage. Base this minimum value on the
maximum engine exhaust flow rate for a given test interval. Either
measure the maximum exhaust flow during a practice run of the test
interval or estimate it based on good engineering judgment (for
example, you might rely on manufacturer-published literature).
    (3) Configure any PM dilution system to have an overall residence
time of (1 to 5) s, as measured from the location of initial diluent
introduction to the location where PM is collected on the sample media.
Also configure the system to have a residence time of at least 0.5 s,
as measured from the location of final diluent introduction to the
location where PM is collected on the sample media. When determining
residence times within sampling system volumes, use an assumed flow
temperature of 25 [deg]C and pressure of 101.325 kPa.
    (4) Control sample temperature to a (47 &plusmn; 5) [deg]C
tolerance, as measured anywhere within 20 cm upstream or downstream of
the PM storage media (such as a filter). Measure this temperature with
a bare-wire junction thermocouple with wires that are (0.500 &plusmn; 0.025)
mm diameter, or with another suitable instrument that has
equivalent performance. The intent of these specifications is to
minimize heat transfer to or from the emissions sample prior to the
final stage of dilution. This is accomplished by initially cooling the
sample through dilution.

• 60. Section 1065.145 is revised to read as follows:

Sec.  1065.145  Gaseous and PM probes, transfer lines, and sampling
system components.

    (a) Continuous and batch sampling. Determine the total mass of each
constituent with continuous or batch sampling, as described in Sec. 
1065.15(c)(2). Both types of sampling systems have probes, transfer
lines, and other sampling system components that are described in this
section.
    (b) Gaseous and PM sample probes. A probe is the first fitting in a
sampling system. It protrudes into a raw or diluted exhaust stream to
extract a sample, such that its inside and outside surfaces are in
contact with the exhaust. A sample is transported out of a probe into a
transfer line, as described in paragraph (c) of this section. The
following provisions apply to sample probes:
    (1) Probe design and construction. Use sample probes with inside
surfaces of 300 series stainless steel or, for raw exhaust sampling,
use any nonreactive material capable of withstanding raw exhaust
temperatures. Locate sample probes where constituents are mixed to
their mean sample concentration. Take into account the mixing of any
crankcase emissions that may be routed into the raw exhaust. Locate
each probe to minimize interference with the flow to other probes. We
recommend that all probes remain free from influences of boundary
layers, wakes, and eddies--especially near the outlet of a raw-exhaust
tailpipe where unintended dilution might occur. Make sure that purging
or back-flushing of a probe does not influence another probe during
testing. You may use a single probe to extract a sample of more than
one constituent as long as the probe meets all the specifications for
each constituent.
    (2) Probe installation on multi-stack engines. We recommend
combining multiple exhaust streams from multi-stack engines before
emission sampling as described in Sec.  1065.130(c)(6). If this is
impractical, you may install symmetrical probes and transfer lines in
each stack. In this case, each stack must be installed such that
similar exhaust velocities are expected at each probe location. Use
identical probe and transfer line diameters, lengths, and bends for
each stack. Minimize the individual transfer line lengths, and manifold
the individual transfer lines into a single transfer line to route the
combined exhaust sample to analyzers and/or batch samplers. For PM
sampling the manifold design must merge the individual sample streams
with a maximum angle of 12.5[deg]
relative to the single sample
stream's flow. Note that the manifold must meet the same specifications
as the transfer line according to paragraph (c) of this section. If you
use this probe configuration and you determine your exhaust flow rates
with a chemical balance of exhaust gas concentrations and either intake
air flow or fuel flow, then show by prior testing that the
concentration of O\2\ in each stack remains within 5% of the mean O\2\
concentration throughout the entire duty cycle.
    (3) Gaseous sample probes. Use either single-port or multi-port
probes for sampling gaseous emissions. You may orient these probes in
any direction relative to the raw or diluted exhaust flow. For some
probes, you must control sample temperatures, as follows:
    (i) For probes that extract NO_X from diluted exhaust,
control the probe's wall temperature to prevent aqueous condensation.
    (ii) For probes that extract hydrocarbons for THC or NMHC analysis
from the diluted exhaust of compression-ignition engines, 2-stroke
spark-ignition engines, or 4-stroke spark-ignition engines below 19 kW,
we recommend heating the probe to minimize hydrocarbon contamination
consistent with good engineering

[[Page 25299]]

judgment. If you routinely fail the contamination check in the 1065.520
pretest check, we recommend heating the probe section to approximately
190 [deg]C to minimize contamination.
    (4) PM sample probes. Use PM probes with a single opening at the
end. Orient PM probes to face directly upstream. If you shield a PM
probe's opening with a PM pre-classifier such as a hat, you may not use
the preclassifier we specify in paragraph (e)(1) of this section. We
recommend sizing the inside diameter of PM probes to approximate
isokinetic sampling at the expected mean flow rate.
    (c) Transfer lines. You may use transfer lines to transport an
extracted sample from a probe to an analyzer, storage medium, or
dilution system, noting certain restrictions for PM sampling in Sec. 
1065.140(e). Minimize the length of all transfer lines by locating
analyzers, storage media, and dilution systems as close to probes as
practical. We recommend that you minimize the number of bends in
transfer lines and that you maximize the radius of any unavoidable
bend. Avoid using 90[deg]
elbows, tees, and cross-fittings in transfer
lines. Where such connections and fittings are necessary, take steps,
using good engineering judgment, to ensure that you meet the
temperature tolerances in this paragraph (c). This may involve
measuring temperature at various locations within transfer lines and
fittings. You may use a single transfer line to transport a sample of
more than one constituent, as long as the transfer line meets all the
specifications for each constituent. The following construction and
temperature tolerances apply to transfer lines:
    (1) Gaseous samples. Use transfer lines with inside surfaces of 300
series stainless steel, PTFE, VitonTM, or any other material
that you demonstrate has better properties for emission sampling. For
raw exhaust sampling, use a non-reactive material capable of
withstanding raw exhaust temperatures. You may use in-line filters if
they do not react with exhaust constituents and if the filter and its
housing meet the same temperature requirements as the transfer lines,
as follows:
    (i) For NO_X transfer lines upstream of either an
NO₂-to-NO converter that meets the specifications of Sec. 
1065.378 or a chiller that meets the specifications of Sec.  1065.376,
maintain a sample temperature that prevents aqueous condensation.
    (ii) For THC transfer lines for testing compression-ignition
engines, 2-stroke spark-ignition engines, or 4-stroke spark-ignition
engines below 19 kW, maintain a wall temperature tolerance throughout
the entire line of (191 &plusmn;11) [deg]C. If you sample from raw
exhaust, you may connect an unheated, insulated transfer line directly
to a probe. Design the length and insulation of the transfer line to
cool the highest expected raw exhaust temperature to no lower than 191
[deg]C, as measured at the transfer line's outlet. For dilute sampling,
you may use a transition zone between the probe and transfer line of up
to 92 cm to allow your wall temperature to transition to (191 &plusmn;11)
[deg]C.
    (2) PM samples. We recommend heated transfer lines or a heated
enclosure to minimize temperature differences between transfer lines
and exhaust constituents. Use transfer lines that are inert with
respect to PM and are electrically conductive on the inside surfaces.
We recommend using PM transfer lines made of 300 series stainless
steel. Electrically ground the inside surface of PM transfer lines.
    (d) Optional sample-conditioning components for gaseous sampling.
You may use the following sample-conditioning components to prepare
gaseous samples for analysis, as long as you do not install or use them
in a way that adversely affects your ability to show that your engines
comply with all applicable gaseous emission standards.
    (1) NO2-to-NO converter. You may use an NO₂-to-NO
converter that meets the efficiency-performance check specified in
Sec.  1065.378 at any point upstream of a NO_X analyzer,
sample bag, or other storage medium.
    (2) Sample dryer. You may use either type of sample dryer described
in this paragraph (d)(2) to decrease the effects of water on gaseous
emission measurements. You may not use a chemical dryer, or use dryers
upstream of PM sample filters.
    (i) Osmotic-membrane. You may use an osmotic-membrane dryer
upstream of any gaseous analyzer or storage medium, as long as it meets
the temperature specifications in paragraph (c)(1) of this section.
Because osmotic-membrane dryers may deteriorate after prolonged
exposure to certain exhaust constituents, consult with the membrane
manufacturer regarding your application before incorporating an
osmotic-membrane dryer. Monitor the dewpoint, T_dew, and
absolute pressure, p_total, downstream of an osmotic-membrane
dryer. You may use continuously recorded values of T_dew and
p_total in the amount of water calculations specified in
Sec.  1065.645. If you do not continuously record these values, you may
use their peak values observed during a test or their alarm setpoints
as constant values in the calculations specified in Sec.  1065.645. You
may also use a nominal p_total, which you may estimate as the
dryer's lowest absolute pressure expected during testing.
    (ii) Thermal chiller. You may use a thermal chiller upstream of
some gas analyzers and storage media. You may not use a thermal chiller
upstream of a THC measurement system for compression-ignition engines,
2-stroke spark-ignition engines, or 4-stroke spark-ignition engines
below 19 kW. If you use a thermal chiller upstream of an
NO₂-to-NO converter or in a sampling system without an
NO₂-to-NO converter, the chiller must meet the
NO₂ loss-performance check specified in Sec.  1065.376.
Monitor the dewpoint, T_dew, and absolute pressure,
p_total, downstream of a thermal chiller. You may use
continuously recorded values of T_dew and p_total
in the emission calculations specified in Sec.  1065.650. If you do not
continuously record these values, you may use the maximum temperature
and minimum pressure values observed during a test or the high alarm
temperature setpoint and the low alarm pressure setpoint as constant
values in the amount of water calculations specified in Sec.  1065.645.
You may also use a nominal p_total, which you may estimate as
the dryer's lowest absolute pressure expected during testing. If it is
valid to assume the degree of saturation in the thermal chiller, you
may calculate T_dew based on the known chiller performance
and continuous monitoring of chiller temperature, T_chiller.
If you do not continuously record values of T_chiller, you
may use its peak value observed during a test, or its alarm setpoint,
as a constant value to determine a constant amount of water according
to Sec.  1065.645. If it is valid to assume that T_chiller is
equal to T_dew, you may use T_chiller in lieu of
T_dew according to Sec.  1065.645. If it is valid to assume a
constant temperature offset between T_chiller and
T_dew, due to a known and fixed amount of sample reheat
between the chiller outlet and the temperature measurement location,
you may factor in this assumed temperature offset value into emission
calculations. If we ask for it, you must show by engineering analysis
or by data the validity of any assumptions allowed by this paragraph
(d)(2)(ii).
    (3) Sample pumps. You may use sample pumps upstream of an analyzer
or storage medium for any gas. Use sample pumps with inside surfaces of
300 series stainless steel, PTFE, or any other material that you
demonstrate has better properties for emission sampling. For some
sample pumps, you must control temperatures, as follows:

[[Page 25300]]

    (i) If you use a NO_X sample pump upstream of either an
NO₂-to-NO converter that meets Sec.  1065.378 or a chiller
that meets Sec.  1065.376, it must be heated to prevent aqueous
condensation.
    (ii) For testing compression-ignition engines, 2-stroke spark-
ignition engines, or 4-stroke spark-ignition engines below 19 kW, if
you use a THC sample pump upstream of a THC analyzer or storage medium,
its inner surfaces must be heated to a tolerance of (191 &plusmn;11) [deg]C.
    (4) Ammonia Scrubber. You may use ammonia scrubbers for any or all
gaseous sampling systems to prevent interference with NH₃,
poisoning of the NO₂-to-NO converter, and deposits in the
sampling system or analyzers. Follow the ammonia scrubber
manufacturer's recommendations or use good engineering judgment in
applying ammonia scrubbers.
    (e) Optional sample-conditioning components for PM sampling. You
may use the following sample-conditioning components to prepare PM
samples for analysis, as long as you do not install or use them in a
way that adversely affects your ability to show that your engines
comply with the applicable PM emission standards. You may condition PM
samples to minimize positive and negative biases to PM results, as follows:
    (1) PM preclassifier. You may use a PM preclassifier to remove
large-diameter particles. The PM preclassifier may be either an
inertial impactor or a cyclonic separator. It must be constructed of
300 series stainless steel. The preclassifier must be rated to remove
at least 50% of PM at an aerodynamic diameter of 10 &mu;m and no more
than 1% of PM at an aerodynamic diameter of 1 &mu;m over the range of
flow rates for which you use it. Follow the preclassifier
manufacturer's instructions for any periodic servicing that may be
necessary to prevent a buildup of PM. Install the preclassifier in the
dilution system downstream of the last dilution stage. Configure the
preclassifier outlet with a means of bypassing any PM sample media so
the preclassifier flow may be stabilized before starting a test. Locate
PM sample media within 75 cm downstream of the preclassifier's exit.
You may not use this preclassifier if you use a PM probe that already
has a preclassifier. For example, if you use a hat-shaped preclassifier
that is located immediately upstream of the probe in such a way that it
forces the sample flow to change direction before entering the probe,
you may not use any other preclassifier in your PM sampling system.
    (2) Other components. You may request to use other PM conditioning
components upstream of a PM preclassifier, such as components that
condition humidity or remove gaseous-phase hydrocarbons from the
diluted exhaust stream. You may use such components only if we approve
them under Sec.  1065.10.

• 61. Section 1065.170 is amended by revising the introductory text and
paragraphs (a) and (c)(1) to read as follows:

Sec.  1065.170  Batch sampling for gaseous and PM constituents.

    Batch sampling involves collecting and storing emissions for later
analysis. Examples of batch sampling include collecting and storing
gaseous emissions in a bag or collecting and storing PM on a filter.
You may use batch sampling to store emissions that have been diluted at
least once in some way, such as with CVS, PFD, or BMD. You may use
batch-sampling to store undiluted emissions.
    (a) Sampling methods. If you extract from a constant-volume flow
rate, sample at a constant-volume flow rate as follows:
    (1) Validate proportional sampling after an emission test as
described in Sec.  1065.545. Use good engineering judgment to select
storage media that will not significantly change measured emission
levels (either up or down). For example, do not use sample bags for
storing emissions if the bags are permeable with respect to emissions
or if they offgas emissions to the extent that it affects your ability
to demonstrate compliance with the applicable gaseous emission
standards. As another example, do not use PM filters that irreversibly
absorb or adsorb gases to the extent that it affects your ability to
demonstrate compliance with the applicable PM emission standard.
    (2) You must follow the requirements in Sec.  1065.140(e)(2)
related to PM dilution ratios. For each filter, if you expect the net
PM mass on the filter to exceed 400 &mu;g, assuming a 38 mm diameter
filter stain area, you may take the following actions in sequence:
    (i) First, reduce filter face velocity as needed to target a filter
loading of 400 &mu;g, down to 50 cm/s or less.
    (ii) Then, for discrete-mode testing only, you may reduce sample
time as needed to target a filter loading of 400 &mu;g, but not below
the minimum sample time specified in the standard-setting part.
    (iii) Then, increase overall dilution ratio above the values
specified in Sec.  1065.140(e)(2) to target a filter loading of 400 &mu;g.
* * * * *
    (c) * * *
    (1) If you use filter-based sampling media to extract and store PM
for measurement, your procedure must meet the following specifications:
    (i) If you expect that a filter's total surface concentration of PM
will exceed 400 &mu;g, assuming a 38 mm diameter filter stain area, for
a given test interval, you may use filter media with a minimum initial
collection efficiency of 98%; otherwise you must use a filter media
with a minimum initial collection efficiency of 99.7%. Collection
efficiency must be measured as described in ASTM D2986-95a
(incorporated by reference in Sec.  1065.1010), though you may rely on
the sample-media manufacturer's measurements reflected in their product
ratings to show that you meet this requirement.
    (ii) The filter must be circular, with an overall diameter of 46.50
&plusmn; 0.6 mm and an exposed diameter of at least 38 mm. See the
cassette specifications in paragraph (c)(1)(vii) of this section.
    (iii) We highly recommend that you use a pure PTFE filter material
that does not have any flow-through support bonded to the back and has
an overall thickness of 40 &plusmn; 20 &mu;m. An inert polymer ring
may be bonded to the periphery of the filter material for support and
for sealing between the filter cassette parts. We consider
Polymethylpentene (PMP) and PTFE inert materials for a support ring,
but other inert materials may be used. See the cassette specifications
in paragraph (c)(1)(vii) of this section. We allow the use of PTFE-
coated glass fiber filter material, as long as this filter media
selection does not affect your ability to demonstrate compliance with
the applicable standards, which we base on a pure PTFE filter material.
Note that we will use pure PTFE filter material for compliance testing,
and we may require you to use pure PTFE filter material for any
compliance testing we require, such as for selective enforcement audits.
    (iv) You may request to use other filter materials or sizes under
the provisions of Sec.  1065.10.
    (v) To minimize turbulent deposition and to deposit PM evenly on a
filter, use a 12.5[deg]
(from center) divergent cone angle to
transition from the transfer-line inside diameter to the exposed
diameter of the filter face. Use 300 series stainless steel for this
transition.
    (vi) Maintain a filter face velocity near 100 cm/s with less than
5% of the recorded flow values exceeding 100 cm/s, unless you expect
either the net PM mass on the filter to exceed 400 &mu;g, assuming a 38
mm diameter filter stain area. Measure face velocity as the volumetric
flow rate of the sample at the

[[Page 25301]]

pressure upstream of the filter and temperature of the filter face as
measured in Sec.  1065.140(e), divided by the filter's exposed area.
You may use the exhaust stack or CVS tunnel pressure for the upstream
pressure if the pressure drop through the PM sampler up to the filter
is less than 2 kPa.
    (vii) Use a clean cassette designed to the specifications of Figure
1 of Sec.  1065.170 and made of any of the following materials:
DelrinTM, 300 series stainless steel, polycarbonate,
acrylonitrile-butadiene-styrene (ABS) resin, or conductive
polypropylene. We recommend that you keep filter cassettes clean by
periodically washing or wiping them with a compatible solvent applied
using a lint-free cloth. Depending upon your cassette material, ethanol
(C₂H₅OH) might be an acceptable solvent. Your
cleaning frequency will depend on your engine's PM and HC emissions.
    (viii) If you store filters in cassettes in an automatic PM
sampler, cover or seal individual filter cassettes after sampling to
prevent communication of semi-volatile matter from one filter to another.
* * * * *

• 62. Section 1065.190 is amended by revising paragraphs (c), (e), (f)
and (g) to read as follows:

Sec.  1065.190  PM-stabilization and weighing environments for
gravimetric analysis.

* * * * *
    (c) Verify the cleanliness of the PM-stabilization environment
using reference filters, as described in Sec.  1065.390(d).
* * * * *
    (e) Verify the following ambient conditions using measurement
instruments that meet the specifications in subpart C of this part:
    (1) Continuously measure dewpoint and ambient temperature. Use
these values to determine if the stabilization and weighing
environments have remained within the tolerances specified in paragraph
(d) of this section for at least 60 min. before weighing sample media
(e.g., filters). We recommend that you use an interlock that
automatically prevents the balance from reporting values if either of
the environments have not been within the applicable tolerances for the
past 60 min.
    (2) Continuously measure atmospheric pressure within the weighing
environment. An acceptable alternative is to use a barometer that
measures atmospheric pressure outside the weighing environment, as long
as you can ensure that atmospheric pressure at the balance is always
within &plusmn;100 Pa of that outside environment during weighing
operations. Record atmospheric pressure as you weigh filters, and use
these pressure values to perform the buoyancy correction in Sec.  1065.690.
    (f) We recommend that you install a balance as follows:
    (1) Install the balance on a vibration-isolation platform to
isolate it from external noise and vibration.
    (2) Shield the balance from convective airflow with a static-
dissipating draft shield that is electrically grounded.
    (3) Follow the balance manufacturer's specifications for all
preventive maintenance.
    (4) Operate the balance manually or as part of an automated
weighing system.
    (g) Minimize static electric charge in the balance environment, as
follows:
    (1) Electrically ground the balance.
    (2) Use 300 series stainless steel tweezers if PM sample media
(e.g., filters) must be handled manually.
    (3) Ground tweezers with a grounding strap, or provide a grounding
strap for the operator such that the grounding strap shares a common
ground with the balance. Make sure grounding straps have an appropriate
resistor to protect operators from accidental shock.
    (4) Provide a static-electricity neutralizer that is electrically
grounded in common with the balance to remove static charge from PM
sample media (e.g., filters), as follows:
    (i) You may use radioactive neutralizers such as a Polonium
(210Po) source. Replace radioactive sources at the intervals
recommended by the neutralizer manufacturer.
    (ii) You may use other neutralizers, such as corona-discharge
ionizers. If you use a corona-discharge ionizer, we recommend that you
monitor it for neutral net charge according to the ionizer
manufacturer's recommendations.
    (5) We recommend that you use a device to monitor the static charge
of PM sample media (e.g., filter) surface.
    (6) We recommend that you neutralize PM sample media (e.g.,
filters) to within &plusmn;2.0 V of neutral. Measure static
voltages as follows:
    (i) Measure static voltage of PM sample media (e.g., filters)
according to the electrostatic voltmeter manufacturer's instructions.
    (ii) Measure static voltage of PM sample media (e.g., filters)
while the media is at least 15 cm away from any grounded surfaces to
avoid mirror image charge interference.

• 63. Section 1065.195 is amended by revising paragraphs (a) and (c)(4)
to read as follows:

Sec.  1065.195  PM-stabilization environment for in-situ analyzers.

    (a) This section describes the environment required to determine PM
in-situ. For in-situ analyzers, such as an inertial balance, this is
the environment within a PM sampling system that surrounds the PM
sample media (e.g., filters). This is typically a very small volume.
* * * * *
    (c) * * *
    (4) Absolute pressure. Use good engineering judgment to maintain a
tolerance of absolute pressure if your PM measurement instrument
requires it.
* * * * *

Subpart C--[Amended]

• 64. Section 1065.201 is amended by revising paragraphs (a) and (b) and
adding paragraph (h) to read as follows:

Sec.  1065.201  Overview and general provisions.

    (a) Scope. This subpart specifies measurement instruments and
associated system requirements related to emission testing in a
laboratory or similar environment and in the field. This includes
laboratory instruments and portable emission measurement systems (PEMS)
for measuring engine parameters, ambient conditions, flow-related
parameters, and emission concentrations.
    (b) Instrument types. You may use any of the specified instruments
as described in this subpart to perform emission tests. If you want to
use one of these instruments in a way that is not specified in this
subpart, or if you want to use a different instrument, you must first
get us to approve your alternate procedure under Sec.  1065.10. Where
we specify more than one instrument for a particular measurement, we
may identify which instrument serves as the reference for comparing
with an alternate procedure.
* * * * *
    (h) Recommended practices. This subpart identifies a variety of
recommended but not required practices for proper measurements. We
believe in most cases it is necessary to follow these recommended
practices for accurate and repeatable measurements and we intend to
follow them as much as possible for our testing. However, we do not
specifically require you to follow these recommended practices to
perform a valid test, as long as you meet the required calibrations and
verifications of measurement systems specified in subpart D of this part.

[[Page 25302]]

• 65. Section 1065.210 is amended by revising paragraph (a) before the
figure to read as follows:

Sec.  1065.210  Work input and output sensors.

    (a) Application. Use instruments as specified in this section to
measure work inputs and outputs during engine operation. We recommend
that you use sensors, transducers, and meters that meet the
specifications in Table 1 of Sec.  1065.205. Note that your overall
systems for measuring work inputs and outputs must meet the linearity
verifications in Sec.  1065.307. We recommend that you measure work
inputs and outputs where they cross the system boundary as shown in
Figure 1 of Sec.  1065.210. The system boundary is different for air-
cooled engines than for liquid-cooled engines. If you choose to measure
work before or after a work conversion, relative to the system
boundary, use good engineering judgment to estimate any work-conversion
losses in a way that avoids overestimation of total work. For example,
if it is impractical to instrument the shaft of an exhaust turbine
generating electrical work, you may decide to measure its converted
electrical work. As another example, you may decide to measure the
tractive (i.e., electrical output) power of a locomotive, rather than
the brake power of the locomotive engine. In these cases, divide the
electrical work by accurate values of electrical generator efficiency
([eta]<1), or assume an efficiency of 1 ([eta]=1), which would over-
estimate brake-specific emissions. For the example of using locomotive
tractive power with a generator efficiency of 1 ([eta]=1), this means
using the tractive power as the brake power in emission calculations.
Do not underestimate any work conversion efficiencies for any
components outside the system boundary that do not return work into the
system boundary. And do not overestimate any work conversion
efficiencies for components outside the system boundary that do return
work into the system boundary. In all cases, ensure that you are able
to accurately demonstrate compliance with the applicable standards.
* * * * *

• 66. Section 1065.215 is amended by revising paragraph (e) to read as
follows:

Sec.  1065.215  Pressure transducers, temperature sensors, and dewpoint
sensors.

* * * * *
    (e) Dewpoint. For PM-stabilization environments, we recommend
chilled-surface hygrometers, which include chilled mirror detectors and
chilled surface acoustic wave (SAW) detectors. For other applications,
we recommend thin-film capacitance sensors. You may use other dewpoint
sensors, such as a wet-bulb/dry-bulb psychrometer, where appropriate.

• 67. Section 1065.220 is amended by revising paragraph (d) to read as
follows:

Sec.  1065.220  Fuel flow meter.

* * * * *
    (d) Flow conditioning. For any type of fuel flow meter, condition
the flow as needed to prevent wakes, eddies, circulating flows, or flow
pulsations from affecting the accuracy or repeatability of the meter.
You may accomplish this by using a sufficient length of straight tubing
(such as a length equal to at least 10 pipe diameters) or by using
specially designed tubing bends, straightening fins, or pneumatic
pulsation dampeners to establish a steady and predictable velocity
profile upstream of the meter. Condition the flow as needed to prevent
any gas bubbles in the fuel from affecting the fuel meter.

• 68. Section 1065.265 is amended by revising paragraph (c) to read as
follows:

Sec.  1065.265  Nonmethane cutter.

* * * * *
    (c) Configuration. Configure the nonmethane cutter with a bypass
line if it is needed for the verification described in Sec.  1065.365.
* * * * *

• 69. Section 1065.270 is amended by revising paragraphs (c) and (d)
introductory text to read as follows:

Sec.  1065.270  Chemiluminescent detector.

* * * * *
    (c) NO2-to-NO converter. Place upstream of the CLD an internal or
external NO₂-to-NO converter that meets the verification in
Sec.  1065.378. Configure the converter with a bypass line if it is
needed to facilitate this verification.
    (d) Humidity effects. You must maintain all CLD temperatures to
prevent aqueous condensation. If you remove humidity from a sample
upstream of a CLD, use one of the following configurations:
* * * * *

• 70. Section 1065.280 is revised to read as follows:

Sec.  1065.280  Paramagnetic and magnetopneumatic O2 detection analyzers.

    (a) Application. You may use a paramagnetic detection (PMD) or
magnetopneumatic detection (MPD) analyzer to measure O₂
concentration in raw or diluted exhaust for batch or continuous
sampling. You may use O₂ measurements with intake air or
fuel flow measurements to calculate exhaust flow rate according to
Sec.  1065.650.
    (b) Component requirements. We recommend that you use a PMD or MPD
analyzer that meets the specifications in Table 1 of Sec.  1065.205.
Note that it must meet the linearity verification in Sec.  1065.307.
You may use a PMD or MPD that has compensation algorithms that are
functions of other gaseous measurements and the engine's known or
assumed fuel properties. The target value for any compensation
algorithm is 0.0% (that is, no bias high and no bias low), regardless
of the uncompensated signal's bias.

• 71. Section 1065.290 is amended by revising paragraph (c)(1) to read as
follows:

Sec.  1065.290  PM gravimetric balance.

* * * * *
    (c) * * *
    (1) Use a pan that centers the PM sample media (such as a filter)
on the weighing pan. For example, use a pan in the shape of a cross
that has upswept tips that center the PM sample media on the pan.
* * * * *

Subpart D--[Amended]

• 72. Section 1065.303 is revised to read as follows:

Sec.  1065.303  Summary of required calibration and verifications.

    The following table summarizes the required and recommended
calibrations and verifications described in this subpart and indicates
when these have to be performed:

    Table 1 of Sec.   1065.303.--Summary of Required Calibration and
                              Verifications
------------------------------------------------------------------------
    Type of calibration or
         verification                     Minimum frequency a
------------------------------------------------------------------------
Sec.   1065.305: Accuracy,     Accuracy: Not required, but recommended
 repeatability and noise.       for initial installation.
                               Repeatability: Not required, but
                                recommended for initial installation.
                               Noise: Not required, but recommended for
                                initial installation.

[[Page 25303]]

Sec.   1065.307: Linearity...  Speed: Upon initial installation, within
                                370 days before testing and after major
                                maintenance.
                               Torque: Upon initial installation, within
                                370 days before testing and after major
                                maintenance.
                               Electrical power: Upon initial
                                installation, within 370 days before
                                testing and after major maintenance.
                               Clean gas and diluted exhaust flows: Upon
                                initial installation, within 370 days
                                before testing and after major
                                maintenance, unless flow is verified by
                                propane check or by carbon or oxygen
                                balance.
                               Raw exhaust flow: Upon initial
                                installation, within 185 days before
                                testing and after major maintenance,
                                unless flow is verified by propane check
                                or by carbon or oxygen balance.
                               Gas analyzers: Upon initial installation,
                                within 35 days before testing and after
                                major maintenance.
                               PM balance: Upon initial installation,
                                within 370 days before testing and after
                                major maintenance.
                               Stand-alone pressure and temperature:
                                Upon initial installation, within 370
                                days before testing and after major
                                maintenance.
Sec.   1065.308: Continuous    Upon initial installation, after system
 analyzer system response and   reconfiguration, and after major
 recording.                     maintenance.
Sec.   1065.309: Continuous    Upon initial installation, after system
 analyzer uniform response.     reconfiguration, and after major
                                maintenance.
Sec.   1065.310: Torque......  Upon initial installation and after major
                                maintenance.
Sec.   1065.315: Pressure,     Upon initial installation and after major
 temperature, dewpoint.         maintenance.
Sec.   1065.320: Fuel flow...  Upon initial installation and after major
                                maintenance.
Sec.   1065.325: Intake flow.  Upon initial installation and after major
                                maintenance.
Sec.   1065.330: Exhaust flow  Upon initial installation and after major
                                maintenance.
Sec.   1065.340: Diluted       Upon initial installation and after major
 exhaust flow (CVS).            maintenance.
Sec.   1065.341: CVS and       Upon initial installation, within 35 days
 batch sampler verification b.  before testing, and after major
                                maintenance.
Sec.   1065.345: Vacuum leak.  Before each laboratory test according to
                                subpart F of this part and before each
                                field test according to subpart J of
                                this part.
Sec.   1065.350: CO2 NDIR H2O  Upon initial installation and after major
 interference.                  maintenance.
Sec.   1065.355: CO NDIR CO2   Upon initial installation and after major
 and H2O interference.          maintenance.
Sec.   1065.360: FID           Calibrate all FID analyzers: Upon initial
 calibration THC FID            installation and after major
 optimization, and THC FID      maintenance.
 verification.                 Optimize and determine CH4 response for
                                THC FID analyzers: upon initial
                                installation and after major
                                maintenance.
                               Verify CH4 response for THC FID
                                analyzers: Upon initial installation,
                                within 185 days before testing, and
                                after major maintenance.
Sec.   1065.362: Raw exhaust   For all FID analyzers: Upon initial
 FID O2 interference.           installation, and after major
                                maintenance.
                               For THC FID analyzers: Upon initial
                                installation, after major maintenance,
                                and after FID optimization according to
                                Sec.   1065.360.
Sec.   1065.365: Nonmethane    Upon initial installation, within 185
 cutter penetration.            days before testing, and after major
                                maintenance.
Sec.   1065.370: CLD CO2 and   Upon initial installation and after major
 H2O quench.                    maintenance.
Sec.   1065.372: NDUV HC and   Upon initial installation and after major
 H2O interference.              maintenance.
Sec.   1065.376: Chiller       Upon initial installation and after major
 NO\2\ penetration.             maintenance.
Sec.   1065.378: NO\2\-to-NO   Upon initial installation, within 35 days
 converter conversion.          before testing, and after major
                                maintenance.
Sec.   1065.390: PM balance    Independent verification: Upon initial
 and weighing.                  installation, within 370 days before
                                testing, and after major maintenance.
                               Zero, span, and reference sample
                                verifications: Within 12 hours of
                                weighing, and after major maintenance.
Sec.   1065.395: Inertial PM   Independent verification: Upon initial
 balance and weighing.          installation, within 370 days before
                                testing, and after major maintenance.
                               Other verifications: Upon initial
                                installation and after major
                                maintenance.
------------------------------------------------------------------------
a Perform calibrations and verifications more frequently, according to
  measurement system manufacturer instructions and good engineering
  judgment.
b The CVS verification described in Sec.   1065.341 is not required for
  systems that agree within &plusmn; 2% based on a chemical balance
  of carbon or oxygen of the intake air, fuel, and diluted exhaust.

• 73. Section 1065.305 is amended by revising paragraphs (d)(4), (d)(8),
and (d)(9)(iii) to read as follows:

Sec.  1065.305  Verifications for accuracy, repeatability, and noise.

* * * * *
    (d) * * *
    (4) Use the instrument to quantify a NIST-traceable reference
quantity, y_ref. For gas analyzers the reference gas must
meet the specifications of Sec.  1065.750. Select a reference quantity
near the mean value expected during testing. For all gas analyzers, use
a quantity near the flow-weighted mean concentration expected at the
standard or expected during testing, whichever is greater. For noise
verification, use the same zero gas from paragraph (e) of this section
as the reference quantity. In all cases, allow time for the instrument
to stabilize while it measures the reference quantity. Stabilization
time may include time to purge an instrument and time to account for
its response.
* * * * *
    (8) Repeat the steps specified in paragraphs (d)(2) through (7) of
this section until you have ten arithmetic means (y\1\, y\2\,
y_i,...y₁₀), ten standard deviations, ([sigma]\1\,
[sigma]\2\, [sigma]_i,...[sigma]₁₀), and ten
errors ([egr]\1\, [egr]\2\, [egr]_i,...[egr]₁₀).
    (9) * * *
    (iii) Noise. Noise is two times the root-mean-square of the ten
standard

[[Page 25304]]

deviations (that is, noise = 2[middot]rms_[sigma]) when the
reference signal is a zero-quantity signal. Refer to the example of a
root-mean-square calculation in Sec.  1065.602. We recommend that
instrument noise be within the specifications in Table 1 of Sec.  1065.205.
* * * * *

• 74. Section 1065.307 is amended by revising paragraphs (b), (c)(6),
(c)(13), and Table 1 and adding paragraphs (d)(8) and (e) before the
newly revised table to read as follows:

Sec.  1065.307  Linearity verification.

* * * * *
    (b) Performance requirements. If a measurement system does not meet
the applicable linearity criteria in Table 1 of this section, correct
the deficiency by re-calibrating, servicing, or replacing components as
needed. Repeat the linearity verification after correcting the
deficiency to ensure that the measurement system meets the linearity
criteria. Before you may use a measurement system that does not meet
linearity criteria, you must demonstrate to us that the deficiency does
not adversely affect your ability to demonstrate compliance with the
applicable standards.
    (c) * * *
    (6) For all measured quantities, use instrument manufacturer
recommendations and good engineering judgment to select reference
values, y_refi, that cover a range of values that you expect
would prevent extrapolation beyond these values during emission
testing. We recommend selecting a zero reference signal as one of the
reference values of the linearity verification. For stand-alone
pressure and temperature linearity verifications, we recommend at least
three reference values. For all other linearity verifications select at
least ten reference values.
* * * * *
    (13) Use the arithmetic means, y_i, and reference values,
y_refi, to calculate least-squares linear regression
parameters and statistical values to compare to the minimum performance
criteria specified in Table 1 of this section. Use the calculations
described in Sec.  1065.602. Using good engineering judgment, you may
weight the results of individual data pairs (i.e., (y_refi,
y_i)), in the linear regression calculations.
    (d) * * *
    (8) Temperature. You may perform the linearity verification for
temperature measurement systems with thermocouples, RTDs, and
thermistors by removing the sensor from the system and using a
simulator in its place. Use a NIST-traceable simulator that is
independently calibrated and, as appropriate, cold-junction
compensated. The simulator uncertainty scaled to temperature must be
less than 0.5% of Tmax. If you use this option, you must use
sensors that the supplier states are accurate to better than 0.5% of
Tmax compared with their standard calibration curve.
    (e) Measurement systems that require linearity verification. Table
1 of this section indicates measurement systems that require linearity
verifications, subject to the following provisions:
    (1) Perform a linearity verification more frequently based on the
instrument manufacturer's recommendation or good engineering judgment.
    (2) The expression ``min'' refers to the minimum reference value
used during the linearity verification. Note that this value may be
zero or a negative value depending on the signal.
    (3) The expression ``max'' generally refers to the maximum
reference value used during the linearity verification. For example for
gas dividers, xmax is the undivided, undiluted, span gas
concentration. The following are special cases where ``max'' refers to
a different value:
    (i) For linearity verification with a PM balance, mmax
refers to the typical mass of a PM filter.
    (ii) For linearity verification of torque, Tmax refers
to the manufacturer's specified engine torque peak value of the lowest
torque engine to be tested.
    (4) The specified ranges are inclusive. For example, a specified
range of 0.98-1.02 for a\1\ means 0.98<=a₁<=1.02.
    (5) These linearity verifications are optional for systems that
pass the flow-rate verification for diluted exhaust as described in
Sec.  1065.341 (the propane check) or for systems that agree within
&plusmn;2% based on a chemical balance of carbon or oxygen of the
intake air, fuel, and exhaust.
    (6) You must meet the a\1\ criteria for these quantities only if
the absolute value of the quantity is required, as opposed to a signal
that is only linearly proportional to the actual value.
    (7) The following provisions apply for stand-alone temperature
measurements:
    (i) The following temperature linearity checks are required:
    (A) Air intake.
    (B) Aftertreatment bed(s), for engines tested with aftertreatment
devices subject to cold-start testing.
    (C) Dilution air for PM sampling, including CVS, double-dilution,
and partial-flow systems.
    (D) PM sample, if applicable.
    (E) Chiller sample, for gaseous sampling systems that use chillers
to dry samples.
    (ii) The following temperature linearity checks are required only
if specified by the engine manufacturer:
    (A) Fuel inlet.
    (B) Air outlet to the test cell's charge air cooler air outlet, for
engines tested with a laboratory heat exchanger that simulates an
installed charge air cooler.
    (C) Coolant inlet to the test cell's charge air cooler, for engines
tested with a laboratory heat exchanger that simulates an installed
charge air cooler.
    (D) Oil in the sump/pan.
    (E) Coolant before the thermostat, for liquid-cooled engines.
    (8) The following provisions apply for stand-alone pressure measurements:
    (i) The following pressure linearity checks are required:
    (A) Air intake restriction.
    (B) Exhaust back pressure.
    (C) Barometer.
    (D) CVS inlet gage pressure.
    (E) Chiller sample, for gaseous sampling systems that use chillers
to dry samples.
    (ii) The following pressure linearity checks are required only if
specified by the engine manufacturer:
    (A) The test cell's charge air cooler and interconnecting pipe
pressure drop, for turbo-charged engines tested with a laboratory heat
exchanger that simulates an installed charge air cooler.
    (B) Fuel outlet.

                                  Table 1 of Sec.   1065.307.--Measurement Systems That Require Linearity Verifications
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                                                        Linearity criteria
                                                   Minimum verification  -------------------------------------------------------------------------------
       Measurement system           Quantity            frequency           [verbarlm]xmin(a\1\-
                                                                              1)+a0 [verbarlm]         a\1\               SEE                  r\2\
--------------------------------------------------------------------------------------------------------------------------------------------------------
Engine speed...................  [fnof]n.......  Within 370 days before   <=0.05 % [fnof]nmax....    0.98-1.02  <=2 % [middot]           >=0.990
                                                  testing.                                                       [fnof]nmax.
Engine torque..................  T.............  Within 370 days before   <=1 % [middot] Tmax....    0.98-1.02  <=2 % [middot] Tmax....  >=0.990
                                                  testing.
Electrical work................  W.............  Within 370 days before   <=1 % [middot] Tmax....    0.98-1.02  <=2 % [middot] Tmax....  >=0.990
                                                  testing.
Fuel flow rate.................  m.............  Within 370 days before   <=1 % [middot] mmax....    0.98-1.02  <=2 % [middot] mmax....  >=0.990
                                                  testing d.

[[Page 25305]]

Intake-air flow rate...........  n.............  Within 370 days before   <=1 % [middot] nmax....    0.98-1.02  <=2 % [middot] nmax....  >=0.990
                                                  testing.
Dilution air flow rate.........  n.............  Within 370 days before   <=1 % [middot] nmax....    0.98-1.02  <=2 % [middot] nmax....  >=0.990
                                                  testing.
Diluted exhaust flow rate......  n.............  Within 370 days before   <=1 % [middot] nmax....    0.98-1.02  <=2 % [middot] nmax....  >=0.990
                                                  testing.
Raw exhaust flow rate..........  n.............  Within 185 days before   <=1 % [middot] nmax....    0.98-1.02  <=2 % [middot] nmax....  >=0.990
                                                  testing.
Batch sampler flow rates.......  n.............  Within 370 days before   <=1 % [middot] nmax....    0.98-1.02  <=2 % [middot] nmax....  >=0.990
                                                  testing.
Gas dividers...................  x/xspan.......  Within 370 days before   <=0.5 % [middot] xmax..    0.98-1.02  <=2 % [middot] xmax....  >=0.990
                                                  testing.
Gas analyzers for laboratory     x.............  Within 35 days before    <=0.5 % [middot] xmax..    0.99-1.01  <=1 % [middot] xmax....  >=0.998
 testing.                                         testing.
Gas analyzers for field testing  x.............  Within 35 days before    <=1 % [middot] xmax....    0.99-1.01  <=1 % [middot] xmax....  >=0.998
                                                  testing.
PM balance.....................  m.............  Within 370 days before   <=1 % [middot] mmax....    0.99-1.01  <=1 % [middot] mmax....  >=0.998
                                                  testing.
Stand-alone pressures..........  p.............  Within 370 days before   <=1 % [middot] pmax....    0.99-1.01  <=1 % [middot] pmax....  >=0.998
                                                  testing.
Analog-to-digital conversion of  T.............  Within 370 days before   <=1 % [middot] Tmax....    0.99-1.01  <=1 % [middot] Tmax....  >=0.998
 stand-alone temperature                          testing.
 signals.
--------------------------------------------------------------------------------------------------------------------------------------------------------

• 75. Section 1065.308 is revised to read as follows:

Sec.  1065.308  Continuous gas analyzer system-response and updating-
recording verification--general.

    This section describes a general verification procedure for
continuous gas analyzer system response and update recording. See Sec. 
1065.309 for verification procedures that apply for systems or
components involving H₂O correction.
    (a) Scope and frequency. Perform this verification after installing
or replacing a gas analyzer that you use for continuous sampling. Also
perform this verification if you reconfigure your system in a way that
would change system response. For example, perform this verification if
you add a significant volume to the transfer lines by increasing their
length or adding a filter; or if you reduce the frequency at which you
sample and record gas-analyzer concentrations. You do not have to
perform this verification for gas analyzer systems used only for
discrete-mode testing.
    (b) Measurement principles. This test verifies that the updating
and recording frequencies match the overall system response to a rapid
change in the value of concentrations at the sample probe. Gas analyzer
systems must be optimized such that their overall response to a rapid
change in concentration is updated and recorded at an appropriate
frequency to prevent loss of information. This test also verifies that
continuous gas analyzer systems meet a minimum response time.
    (c) System requirements. To demonstrate acceptable updating and
recording with respect to the system's overall response, use good
engineering judgment to select one of the following criteria that your
system must meet:
    (1) The product of the mean rise time and the frequency at which
the system records an updated concentration must be at least 5, and the
product of the mean fall time and the frequency at which the system
records an updated concentration must be at least 5. This criterion
makes no assumption regarding the frequency content of changes in
emission concentrations during emission testing; therefore, it is valid
for any testing. In any case the mean rise time and the mean fall time
must be no more than 10 seconds.
    (2) The frequency at which the system records an updated
concentration must be at least 5 Hz. This criterion assumes that the
frequency content of significant changes in emission concentrations
during emission testing do not exceed 1 Hz. In any case the mean rise
time and the mean fall time must be no more than 10 seconds.
    (3) You may use other criteria if we approve the criteria in advance.
    (4) You may meet the overall PEMS verification in Sec.  1065.920
instead of the verification in this section for field testing with PEMS.
    (d) Procedure. Use the following procedure to verify the response
of a continuous gas analyzer system:
    (1) Instrument setup. Follow the analyzer system manufacturer's
start-up and operating instructions. Adjust the system as needed to
optimize performance.
    (2) Equipment setup. We recommend using minimal lengths of gas
transfer lines between all connections and fast-acting three-way valves
(2 inlets, 1 outlet) to control the flow of zero and blended span gases
to the analyzers. You may use a gas mixing or blending device to
equally blend an NO-CO-CO₂-C₃H₈-
CH₄, balance N₂ span gas with a span gas of
NO₂, balance purified synthetic air. Standard binary span
gases may also be used, where applicable, in place of blended NO-CO-
CO₂-C₃H₈-CH₄, balance
N₂ span gas, but separate response tests must then be run
for each analyzer. In designing your experimental setup, avoid pressure
pulsations due to stopping the flow through the gas-blending device.
Note that you may omit any of these gas constituents if they are not
relevant to your analyzers for this verification.
    (3) Data collection. (i) Start the flow of zero gas.
    (ii) Allow for stabilization, accounting for transport delays and
the slowest instrument's full response.
    (iii) Start recording data at the frequency used during emission
testing. Each recorded value must be a unique updated concentration
measured by the analyzer; you may not use interpolation to increase the
number of recorded values.
    (iv) Switch the flow to allow the blended span gases to flow to the
analyzer.
    (v) Allow for transport delays and the slowest instrument's full
response.
    (vi) Repeat the steps in paragraphs (d)(3)(i) through (v) of this
section to record seven full cycles, ending with zero gas flowing to
the analyzers.
    (vii) Stop recording.
    (e) Performance evaluation. (1) If you chose to demonstrate
compliance with paragraph (c)(1) of this section, use the data from
paragraph (d)(3) of this section to calculate the mean rise time,
t_10-90, and mean fall time, t_10-90, for each of
the analyzers. Multiply these times (in seconds) by their respective
recording frequencies in Hertz (1/second). The value for each result
must be at least 5. If the value is less than 5, increase the recording
frequency or adjust the flows or design of the sampling system to
increase the rise time and fall time as needed. You may

[[Page 25306]]

also configure digital filters to increase rise and fall times. The
mean rise time and mean fall time must be no greater than 10 seconds.
    (2) If a measurement system fails the criterion in paragraph (e)(1)
of this section, ensure that signals from the system are updated and
recorded at a frequency of at least 5 Hz. In any case, the mean rise
time and mean fall time must be no greater than 10 seconds.
    (3) If a measurement system fails the criteria in paragraphs (e)(1)
and (2) of this section, you may use the continuous analyzer system
only if the deficiency does not adversely affect your ability to show
compliance with the applicable standards.

• 76. Section 1065.309 is revised to read as follows:

Sec.  1065.309  Continuous gas analyzer system-response and updating-
recording verification--with humidified-response verification.

    This section describes a verification procedure for continuous gas
analyzer system response and update recording for systems or components
involving H₂O correction. See Sec.  1065.308 for verification
procedures that apply for systems not involving humidification.
    (a) Scope and frequency. Perform this verification to determine a
continuous gas analyzer's response, where one analyzer's response is
compensated by another's to quantify a gaseous emission. For this check
we consider water vapor a gaseous constituent. You do not have to
perform this verification for batch gas analyzer systems or for
continuous analyzer systems that are only used for discrete-mode
testing. Perform this verification after initial installation (i.e.
test cell commissioning). The verification in this section is required
for initial installation of systems or components involving
H₂O correction. For later verifications, you may use the
procedures specified in Sec.  1065.308, as long as your system includes
no replacement components involving H₂O correction that have
never been verified using the procedures in this section.
    (b) Measurement principles. This procedure verifies the time-
alignment and uniform response of continuously combined gas
measurements. For this procedure, ensure that all compensation
algorithms and humidity corrections are turned on.
    (c) System requirements. Demonstrate that continuously combined
concentration measurements have a uniform rise and fall during a system
response to a rapid change in multiple gas concentrations. You must
meet one of the following criteria:
    (1) The product of the mean rise time and the frequency at which
the system records an updated concentration must be at least 5, and the
product of the mean fall time and the frequency at which the system
records an updated concentration must be at least 5. This criterion
makes no assumption regarding the frequency content of changes in
emission concentrations during emission testing; therefore, it is valid
for any testing. In no case may the mean rise time or the mean fall
time be more than 10 seconds.
    (2) The frequency at which the system records an updated
concentration must be at least 5 Hz. This criterion assumes that the
frequency content of significant changes in emission concentrations
during emission testing do not exceed 1 Hz. In no case may the mean
rise time or the mean fall time be more than 10 seconds.
    (3) You may use other criteria if we approve them in advance.
    (4) You may meet the overall PEMS verification in Sec.  1065.920
instead of the verification in this section for field testing with PEMS.
    (d) Procedure. Use the following procedure to verify the response
of a continuous gas analyzer system:
    (1) Instrument setup. Follow the analyzer system manufacturer's
start-up and operating instructions. Adjust the system as needed to
optimize performance.
    (2) Equipment setup. We recommend using minimal lengths of gas
transfer lines between all connections and fast-acting three-way valves
(2 inlets, 1 outlet) to control the flow of zero and blended span gases
to the analyzers. You may use a gas blending or mixing device to
equally blend a span gas of NO-CO-CO₂-
C₃H₈-CH₄, balance N₂, with
a span gas of NO₂, balance purified synthetic air. Standard
binary span gases may be used, where applicable, in place of blended
NO-CO-CO₂-C₃H₈-CH₄, balance
N₂ span gas, but separate response tests must then be run
for each analyzer. In designing your experimental setup, avoid pressure
pulsations due to stopping the flow through the gas blending device.
Span gases must be humidified before entering the analyzer; however,
you may not humidify NO₂ span gas by passing it through a
sealed humidification vessel that contains water. We recommend
humidifying your NO-CO-CO₂-C₃H₈-
CH₄, balance N₂ blended gas by flowing the gas
mixture through a sealed vessel that humidifies the gas by bubbling it
through distilled water and then mixing the gas with dry NO₂
gas, balance purified synthetic air. If your system does not use a
sample dryer to remove water from the sample gas, you must humidify
your span gas by flowing the gas mixture through a sealed vessel that
humidifies the gas to the highest sample dewpoint that you estimate
during emission sampling by bubbling it through distilled water. If
your system uses a sample dryer during testing that has passed the
sample dryer verification check in Sec.  1065.342, you may introduce
the humidified gas mixture downstream of the sample dryer by bubbling
it through distilled water in a sealed vessel at (25 &plusmn; 10)
[deg]C, or a temperature greater than the dewpoint determined in Sec. 
1065.145(d)(2). In all cases, maintain the humidified gas temperature
downstream of the vessel at least 5 [deg]C above its local dewpoint in
the line. We recommend that you heat all gas transfer lines and valves
located downstream of the vessel as needed to avoid condensation. Note
that you may omit any of these gas constituents if they are not
relevant to your analyzers for this verification. If any of your gas
constituents are not susceptible to water compensation, you may perform
the response check for these analyzers without humidification.
    (3) Data collection. (i) Start the flow of zero gas.
    (ii) Allow for stabilization, accounting for transport delays and
the slowest instrument's full response.
    (iii) Start recording data at the frequency used during emission
testing. Each recorded value must be a unique updated concentration
measured by the analyzer; you may not use interpolation to increase the
number of recorded values.
    (iv) Switch the flow to allow the blended span gases to flow to the
analyzers.
    (v) Allow for transport delays and the slowest instrument's full
response.
    (vi) Repeat the steps in paragraphs (d)(3)(i) through (v) of this
section to record seven full cycles, ending with zero gas flowing to
the analyzers.
    (vii) Stop recording.
    (e) Performance evaluations. (1) If you chose to demonstrate
compliance with paragraph (c)(1) of this section, use the data from
paragraph (d)(3) of this section to calculate the mean rise time,
t_10-90, and mean fall time, t_S90-10, for each of
the analyzers. Multiply these times (in seconds) by their respective
recording frequencies in Hz (1/second). The value for each result must
be at least 5. If the value is less than 5, increase the recording
frequency or adjust the flows or design of the sampling system to
increase the rise time and fall time as needed. You may also configure
digital filters to increase rise and fall times. In no case may the

[[Page 25307]]

mean rise time or mean fall time be greater than 10 seconds.
    (2) If a measurement system fails the criterion in paragraph (e)(1)
of this section, ensure that signals from the system are updated and
recorded at a frequency of at least 5 Hz. In no case may the mean rise
time or mean fall time be greater than 10 seconds.
    (3) If a measurement system fails the criteria in paragraphs (e)(1)
and (2) of this section, you may use the continuous analyzer system
only if the deficiency does not adversely affect your ability to show
compliance with the applicable standards.

• 77. Section 1065.310 is amended by revising paragraph (d) to read as
follows:

Sec.  1065.310  Torque calibration.

* * * * *
    (d) Strain gage or proving ring calibration. This technique applies
force either by hanging weights on a lever arm (these weights and their
lever arm length are not used as part of the reference torque
determination) or by operating the dynamometer at different torques.
Apply at least six force combinations for each applicable torque-
measuring range, spacing the force quantities about equally over the
range. Oscillate or rotate the dynamometer during calibration to reduce
frictional static hysteresis. In this case, the reference torque is
determined by multiplying the force output from the reference meter
(such as a strain gage or proving ring) by its effective lever-arm
length, which you measure from the point where the force measurement is
made to the dynamometer's rotational axis. Make sure you measure this
length perpendicular to the reference meter's measurement axis and
perpendicular to the dynamometer's rotational axis.

• 78. Section 1065.315 is amended by revising paragraph (a)(2) to read as
follows:

Sec.  1065.315  Pressure, temperature, and dewpoint calibration.

    (a) * * *
    (2) Temperature. We recommend digital dry-block or stirred-liquid
temperature calibrators, with data logging capabilities to minimize
transcription errors. We recommend using calibration reference
quantities that are NIST-traceable within 0.5% uncertainty. You may
perform the linearity verification for temperature measurement systems
with thermocouples, RTDs, and thermistors by removing the sensor from
the system and using a simulator in its place. Use a NIST-traceable
simulator that is independently calibrated and, as appropriate, cold-
junction compensated. The simulator uncertainty scaled to temperature
must be less than 0.5% of Tmax. If you use this option, you
must use sensors that the supplier states are accurate to better than
0.5% of Tmax compared with their standard calibration curve.
* * * * *

• 79. Section 1065.340 is amended by revising paragraphs (f)(5),
(f)(6)(ii), (f)(7), (f)(9), (f)(10), (g)(6)(i), and Figure 1 to read as
follows:

Sec.  1065.340  Diluted exhaust flow (CVS) calibration.

* * * * *
    (f) * * *
    (5) Set the variable restrictor to its wide-open position. Instead
of a variable restrictor, you may alternately vary the pressure
downstream of the CFV by varying blower speed or by introducing a
controlled leak. Note that some blowers have limitations on nonloaded
conditions.
    (6) * * *
    (ii) The mean dewpoint of the calibration air, T_dew. See
Sec.  1065.640 for permissible assumptions during emission measurements.
* * * * *
    (7) Incrementally close the restrictor valve or decrease the
downstream pressure to decrease the differential pressure across the
CFV,[Delta]P_CFV.
* * * * *
    (9) Determine C_d and the lowest allowable pressure
ratio, r, according to Sec.  1065.640.
    (10) Use Cd to determine CFV flow during an emission test. Do not
use the CFV below the lowest allowed r, as determined in Sec.  1065.640.
* * * * *
    (g) * * *
    (6) * * *
    (i) The mean flow rate of the reference flow meter,n_ref.
This may include several measurements of different quantities, such as
reference meter pressures and temperatures, for calculating n_ref.
* * * * *
BILLING CODE 6560-50-P

[[Page 25308]]
[GRAPHIC] [TIFF OMITTED] TR06MY08.020
BILLING CODE 6560-50-C

• 80. Section 1065.341 is amended by revising paragraphs (d) introductory
text, (d)(7), and (g) introductory text to read as follows:

Sec.  1065.341  CVS and batch sampler verification (propane check).

* * * * *
    (d) If you performed the vacuum-side leak verification of the HC
sampling system as described in paragraph (c)(8) of this section, you
may use the HC contamination procedure in Sec.  1065.520(g) to verify
HC contamination. Otherwise, zero, span, and verify contamination of
the HC sampling system, as follows:
* * * * *
    (7) When the overflow HC concentration does not exceed 2 &mu;mol/
mol, record this value as x_THCinit and use it to correct for
HC contamination as described in Sec.  1065.660.
* * * * *

[[Page 25309]]

    (g) You may repeat the propane check to verify a batch sampler,
such as a PM secondary dilution system.
* * * * *
• 81. A new Sec.  1065.342 is added to read as follows:

Sec.  1065.342  Sample dryer verification.

    (a) Scope and frequency. If you use a sample dryer as allowed in
Sec.  1065.145(d)(2) to remove water from the sample gas, verify the
performance upon installation, after major maintenance, for thermal
chiller. For osmotic membrane dryers, verify the performance upon
installation, after major maintenance, and within 35 days of testing.
    (b) Measurement principles. Water can inhibit an analyzer's ability
to properly measure the exhaust component of interest and thus is
sometimes removed before the sample gas reaches the analyzer. For
example water can negatively interfere with a CLD's NO_X
response through collisional quenching and can positively interfere
with an NDIR analyzer by causing a response similar to CO.
    (c) System requirements. The sample dryer must meet the
specifications as determined in Sec.  1065.145(d)(2) for dewpoint,
T_dew, and absolute pressure, p_total, downstream
of the osmotic-membrane dryer or thermal chiller.
    (d) Sample dryer verification procedure. Use the following method
to determine sample dryer performance, or use good engineering judgment
to develop a different protocol:
    (1) Use PTFE or stainless steel tubing to make necessary connections.
    (2) Humidify N\2\ or purified air by bubbling it through distilled
water in a sealed vessel that humidifies the gas to the highest sample
dewpoint that you estimate during emission sampling.
    (3) Introduce the humidified gas upstream of the sample dryer.
    (4) Downstream of the vessel, maintain the humidified gas
temperature at least 5 [deg]C above its dewpoint.
    (5) Measure the humidified gas dewpoint, T_dew, and
pressure, p_total, as close as possible to the inlet of the
sample dryer to verify the dewpoint is the highest that you estimated
during emission sampling.
    (6) Measure the humidified gas dewpoint, T_dew, and
pressure, p_total, as close as possible to the outlet of the
sample dryer.
    (7) The sample dryer meets the verification if the results of
paragraph (d)(6) of this section are less than the dew point
corresponding to the sample dryer specifications as determined in Sec. 
1065.145(d)(2) plus 2 [deg]C or if the mole fraction from (d)(6) is
less than the corresponding sample dryer specifications plus 0.002 mol/mol.
    (e) Alternate sample dryer verification procedure. The following
method may be used in place of the sample dryer verification procedure
in (d) of this section. If you use a humidity sensor for continuous
monitoring of dewpoint at the sample dryer outlet you may skip the
performance check in Sec.  1065.342(d), but you must make sure that the
dryer outlet humidity is below the minimum values used for quench,
interference, and compensation checks.

• 82. Section 1065.345 is revised to read as follows:

Sec.  1065.345  Vacuum-side leak verification.

    (a) Scope and frequency. Verify that there are no significant
vacuum-side leaks using one of the leak tests described in this section
upon initial sampling system installation, after maintenance such as
pre-filter changes, and within eight hours before each duty-cycle
sequence. This verification does not apply to any full-flow portion of
a CVS dilution system.
    (b) Measurement principles. A leak may be detected either by
measuring a small amount of flow when there should be zero flow, or by
detecting the dilution of a known concentration of span gas when it
flows through the vacuum side of a sampling system.
    (c) Low-flow leak test. Test a sampling system for low-flow leaks
as follows:
    (1) Seal the probe end of the system by taking one of the following
steps:
    (i) Cap or plug the end of the sample probe.
    (ii) Disconnect the transfer line at the probe and cap or plug the
transfer line.
    (iii) Close a leak-tight valve located in the sample transfer line
within 92 cm of the probe.
    (2) Operate all vacuum pumps. After stabilizing, verify that the
flow through the vacuum-side of the sampling system is less than 0.5%
of the system's normal in-use flow rate. You may estimate typical
analyzer and bypass flows as an approximation of the system's normal
in-use flow rate.
    (d) Dilution-of-span-gas leak test. You may use any gas analyzer
for this test. If you use a FID for this test, correct for any HC
contamination in the sampling system according to Sec.  1065.660. To
avoid misleading results from this test, we recommend using only
analyzers that have a repeatability of 0.5% or better at the span gas
concentration used for this test. Perform a vacuum-side leak test as
follows:
    (1) Prepare a gas analyzer as you would for emission testing.
    (2) Supply span gas to the analyzer port and verify that it
measures the span gas concentration within its expected measurement
accuracy and repeatability.
    (3) Route overflow span gas to one of the following locations in
the sampling system:
    (i) The end of the sample probe.
    (ii) Disconnect the transfer line at the probe connection, and
overflow the span gas at the open end of the transfer line.
    (iii) A three-way valve installed in-line between a probe and its
transfer line, such as a system overflow zero and span port.
    (4) Verify that the measured overflow span gas concentration is
within &plusmn; 0.5% of the span gas concentration. A measured
value lower than expected indicates a leak, but a value higher than
expected may indicate a problem with the span gas or the analyzer
itself. A measured value higher than expected does not indicate a leak.
    (e) Vacuum-decay leak test. To perform this test you must apply a
vacuum to the vacuum-side volume of your sampling system and then
observe the leak rate of your system as a decay in the applied vacuum.
To perform this test you must know the vacuum-side volume of your
sampling system to within &plusmn; 10% of its true volume. For this
test you must also use measurement instruments that meet the
specifications of subpart C of this part and of this subpart D. Perform
a vacuum-decay leak test as follows:
    (1) Seal the probe end of the system as close to the probe opening
as possible by taking one of the following steps:
    (i) Cap or plug the end of the sample probe.
    (ii) Disconnect the transfer line at the probe and cap or plug the
transfer line.
    (iii) Close a leak-tight valve in-line between a probe and transfer
line.
    (2) Operate all vacuum pumps. Draw a vacuum that is representative
of normal operating conditions. In the case of sample bags, we
recommend that you repeat your normal sample bag pump-down procedure
twice to minimize any trapped volumes.
    (3) Turn off the sample pumps and seal the system. Measure and
record the absolute pressure of the trapped gas and optionally the
system absolute temperature. Wait long enough for any transients to
settle and long enough for a leak at 0.5% to have caused a pressure
change of at least 10 times the resolution of the pressure transducer,
then again record the pressure and optionally temperature.
    (4) Calculate the leak flow rate based on an assumed value of zero for

[[Page 25310]]

pumped-down bag volumes and based on known values for the sample system
volume, the initial and final pressures, optional temperatures, and
elapsed time. Using the calculations specified in 1065.644, verify that
the vacuum-decay leak flow rate is less than 0.5% of the system's
normal in-use flow rate.

• 83. Section 1065.350 is amended by revising paragraphs (c) and (d) to
read as follows:

Sec.  1065.350  H2O interference verification for CO2 NDIR analyzers.

* * * * *
    (c) System requirements. A CO₂ NDIR analyzer must have
an H₂O interference that is within (0.0 &plusmn;0.4)
mmol/mol, though we strongly recommend a lower interference that is
within (0.0 &plusmn;0.2) mmol/mol.
    (d) Procedure. Perform the interference verification as follows:
    (1) Start, operate, zero, and span the CO₂ NDIR analyzer
as you would before an emission test.
    (2) Create a humidified test gas by bubbling zero air that meets
the specifications in Sec.  1065.750 through distilled water in a
sealed vessel. If the sample is not passed through a dryer, control the
vessel temperature to generate an H₂O level at least as high
as the maximum expected during testing. If the sample is passed through
a dryer during testing, control the vessel temperature to generate an
H₂O level at least as high as the level determined in Sec. 
1065.145(d)(2).
    (3) Introduce the humidified test gas into the sample system. You
may introduce it downstream of any sample dryer, if one is used during
testing.
    (4) Measure the humidified test gas dewpoint, T_dew, and
pressure, p_total, as close as possible to the inlet of the
analyzer.
    (5) Downstream of the vessel, maintain the humidified test gas
temperature at least 5 [deg]C above its dewpoint.
    (6) Allow time for the analyzer response to stabilize.
Stabilization time may include time to purge the transfer line and to
account for analyzer response.
    (7) While the analyzer measures the sample's concentration, record
30 seconds of sampled data. Calculate the arithmetic mean of this data.
The analyzer meets the interference verification if this value is
within (0 &plusmn;0.4) mmol/mol.
* * * * *

• 84. Section 1065.355 is amended by revising paragraph (d) to read as
follows:

Sec.  1065.355  H2O and CO2 interference verification for CO NDIR analyzers.

* * * * *
    (d) Procedure. Perform the interference verification as follows:
    (1) Start, operate, zero, and span the CO NDIR analyzer as you
would before an emission test.
    (2) Create a humidified CO₂ test gas by bubbling a
CO₂ span gas through distilled water in a sealed vessel. If
the sample is not passed through a dryer, control the vessel
temperature to generate an H₂O level at least as high as the
maximum expected during testing. If the sample is passed through a
dryer during testing, control the vessel temperature to generate an
H₂O level at least as high as the level determined in Sec. 
1065.145(d)(2). Use a CO₂ span gas concentration at least as
high as the maximum expected during testing.
    (3) Introduce the humidified CO₂ test gas into the
sample system. You may introduce it downstream of any sample dryer, if
one is used during testing.
    (4) Measure the humidified CO₂ test gas dewpoint,
T_dew, and pressure, p_total, as close as possible
to the inlet of the analyzer.
    (5) Downstream of the vessel, maintain the humidified gas
temperature at least 5 [deg]C above its dewpoint.
    (6) Allow time for the analyzer response to stabilize.
Stabilization time may include time to purge the transfer line and to
account for analyzer response.
    (7) While the analyzer measures the sample's concentration, record
its output for 30 seconds. Calculate the arithmetic mean of this data.
    (8) The analyzer meets the interference verification if the result
of paragraph (d)(7) of this section meets the tolerance in paragraph
(c) of this section.
    (9) You may also run interference procedures for CO₂ and
H₂O separately. If the CO₂ and H₂O
levels used are higher than the maximum levels expected during testing,
you may scale down each observed interference value by multiplying the
observed interference by the ratio of the maximum expected
concentration value to the actual value used during this procedure. You
may run the separate interference procedures concentrations of
H₂O (down to 0.025 mol/mol H₂O content) that are
lower than the maximum levels expected during testing, but you must
scale up the observed H₂O interference by multiplying the
observed interference by the ratio of the maximum expected
H₂O concentration value to the actual value used during this
procedure. The sum of the two scaled interference values must meet the
tolerance in paragraph (c) of this section.
* * * * *

• 85. Section 1065.360 is revised to read as follows:

Sec.  1065.360  FID optimization and verification.

    (a) Scope and frequency. For all FID analyzers, calibrate the FID
upon initial installation. Repeat the calibration as needed using good
engineering judgment. For a FID that measures THC, perform the
following steps:
    (1) Optimize the response to various hydrocarbons after initial
analyzer installation and after major maintenance as described in
paragraph (c) of this section.
    (2) Determine the methane (CH₄) response factor after
initial analyzer installation and after major maintenance as described
in paragraph (d) of this section.
    (3) Verify the methane (CH₄) response within 185 days
before testing as described in paragraph (e) of this section.
    (b) Calibration. Use good engineering judgment to develop a
calibration procedure, such as one based on the FID-analyzer
manufacturer's instructions and recommended frequency for calibrating
the FID. Alternately, you may remove system components for off-site
calibration. For a FID that measures THC, calibrate using
C₃H₈ calibration gases that meet the
specifications of Sec.  1065.750. For a FID that measures
CH₄, calibrate using CH₄ calibration gases that
meet the specifications of Sec.  1065.750. We recommend FID analyzer
zero and span gases that contain approximately the flow-weighted mean
concentration of O₂ expected during testing. If you use a
FID to measure methane (CH₄) downstream of a nonmethane
cutter, you may calibrate that FID using CH₄ calibration
gases with the cutter. Regardless of the calibration gas composition,
calibrate on a carbon number basis of one (C₁). For example,
if you use a C₃H₈ span gas of concentration 200
&mu;mol/mol, span the FID to respond with a value of 600 &mu;mol/mol.
As another example, if you use a CH₄ span gas with a
concentration of 200 &mu;mol/mol, span the FID to respond with a value
of 200 &mu;mol/mol.
    (c) THC FID response optimization. This procedure is only for FID
analyzers that measure THC. Use good engineering judgment for initial
instrument start-up and basic operating adjustment using FID fuel and
zero air. Heated FIDs must be within their required operating
temperature ranges. Optimize FID response at the most

[[Page 25311]]

common analyzer range expected during emission testing. Optimization
involves adjusting flows and pressures of FID fuel, burner air, and
sample to minimize response variations to various hydrocarbon species
in the exhaust. Use good engineering judgment to trade off peak FID
response to propane calibration gases to achieve minimal response
variations to different hydrocarbon species. For an example of trading
off response to propane for relative responses to other hydrocarbon
species, see SAE 770141 (incorporated by reference in Sec.  1065.1010).
Determine the optimum flow rates and/or pressures for FID fuel, burner
air, and sample and record them for future reference.
    (d) THC FID CH4 response factor determination. This procedure is
only for FID analyzers that measure THC. Since FID analyzers generally
have a different response to CH4 versus C₃H₈,
determine each THC FID analyzer's CH₄ response factor,
RF_CH4[THC-FID], after FID optimization. Use the most recent
RF_CH4[THC-FID] measured according to this section in the
calculations for HC determination described in Sec.  1065.660 to
compensate for CH₄ response. Determine
RF_CH4[THC-FID] as follows, noting that you do not determine
RF_CH4[THC-FID] for FIDs that are calibrated and spanned
using CH₄ with a nonmethane cutter:
    (1) Select a C₃H₈ span gas concentration that
you use to span your analyzers before emission testing. Use only span
gases that meet the specifications of Sec.  1065.750. Record the
C₃H₈ concentration of the gas.
    (2) Select a CH₄ span gas concentration that you use to
span your analyzers before emission testing. Use only span gases that
meet the specifications of Sec.  1065.750. Record the CH₄
concentration of the gas.
    (3) Start and operate the FID analyzer according to the
manufacturer's instructions.
    (4) Confirm that the FID analyzer has been calibrated using
C₃H₈. Calibrate on a carbon number basis of one
(C₁). For example, if you use a C₃H₈
span gas of concentration 200 &mu;mol/mol, span the FID to respond with
a value of 600 &mu;mol/mol.
    (5) Zero the FID with a zero gas that you use for emission testing.
    (6) Span the FID with the C₃H₈ span gas that
you selected under paragraph (d)(1) of this section.
    (7) Introduce at the sample port of the FID analyzer, the CH₄
span gas that you selected under paragraph (d)(2) of this section.
    (8) Allow time for the analyzer response to stabilize.
Stabilization time may include time to purge the analyzer and to
account for its response.
    (9) While the analyzer measures the CH₄ concentration,
record 30 seconds of sampled data. Calculate the arithmetic mean of
these values.
    (10) Divide the mean measured concentration by the recorded span
concentration of the CH₄ calibration gas. The result is the
FID analyzer's response factor for CH4, RF_{CH4[THC-FID].}
    (e) THC FID methane (CH4) response verification. This procedure is
only for FID analyzers that measure THC. If the value of
RF_CH4[THC-FID] from paragraph (d) of this section is within
&plusmn;5.0% of its most recent previously determined value, the
THC FID passes the methane response verification. For example, if the
most recent previous value for RF_CH4[THC-FID] was 1.05 and
it changed by &plusmn;0.05 to become 1.10 or it changed by -0.05 to
become 1.00, either case would be acceptable because &plusmn;4.8%
is less than &plusmn;5.0%. Verify RF_CH4[THC-FID] as follows:
    (1) First verify that the flow rates and/or pressures of FID fuel,
burner air, and sample are each within &plusmn;0.5% of their most
recent previously recorded values, as described in paragraph (c) of
this section. You may adjust these flow rates as necessary. Then
determine the RF_CH4[THC-FID] as described in paragraph (d)
of this section and verify that it is within the tolerance specified in
this paragraph (e).
    (2) If RF_CH4[THC-FID] is is not within the tolerance
specified in this paragraph (e), re-optimize the FID response as
described in paragraph (c) of this section.
    (3) Determine a new RF_CH4[THC-FID] as described in
paragraph (d) of this section. Use this new value of
RF_CH4[THC-FID] in the calculations for HC determination, as
described in Sec.  1065.660.

• 86. Section 1065.362 is amended by revising paragraph (d) to read as
follows:

Sec.  1065.362  Non-stoichiometric raw exhaust FID O2 interference
verification.

* * * * *
    (d) Procedure. Determine FID O₂ interference as follows,
noting that you may use one or more gas dividers to create the
reference gas concentrations that are required to perform this
verification:
    (1) Select three span reference gases that contain a
C₃H₈ concentration that you use to span your
analyzers before emission testing. Use only span gases that meet the
specifications of Sec.  1065.750. You may use CH₄ span
reference gases for FIDs calibrated on CH₄ with a nonmethane
cutter. Select the three balance gas concentrations such that the
concentrations of O₂ and N₂ represent the
minimum, maximum, and average O₂ concentrations expected
during testing. The requirement for using the average O₂
concentration can be removed if you choose to calibrate the FID with
span gas balanced with the average expected oxygen concentration.
    (2) Confirm that the FID analyzer meets all the specifications of
Sec.  1065.360.
    (3) Start and operate the FID analyzer as you would before an
emission test. Regardless of the FID burner's air source during
testing, use zero air as the FID burner's air source for this verification.
    (4) Zero the FID analyzer using the zero gas used during emission
testing.
    (5) Span the FID analyzer using a span gas that you use during
emission testing.
    (6) Check the zero response of the FID analyzer using the zero gas
used during emission testing. If the mean zero response of 30 seconds
of sampled data is within &plusmn;0.5% of the span reference value
used in paragraph (d)(5) of this section, then proceed to the next
step; otherwise restart the procedure at paragraph (d)(4) of this section.
    (7) Check the analyzer response using the span gas that has the
minimum concentration of O₂ expected during testing. Record
the mean response of 30 seconds of stabilized sample data as x_O2minHC.
    (8) Check the zero response of the FID analyzer using the zero gas
used during emission testing. If the mean zero response of 30 seconds
of stabilized sample data is within &plusmn;0.5% of the span
reference value used in paragraph (d)(5) of this section, then proceed
to the next step; otherwise restart the procedure at paragraph (d)(4)
of this section.
    (9) Check the analyzer response using the span gas that has the
average concentration of O₂ expected during testing. Record
the mean response of 30 seconds of stabilized sample data as
x_O2avgHC.
    (10) Check the zero response of the FID analyzer using the zero gas
used during emission testing. If the mean zero response of 30 seconds
of stabilized sample data is within &plusmn;0.5% of the span
reference value used in paragraph (d)(5) of this section, proceed to
the next step; otherwise restart the procedure at paragraph (d)(4) of
this section.
    (11) Check the analyzer response using the span gas that has the
maximum concentration of O₂ expected during testing. Record
the mean response of 30 seconds of stabilized sample data as
x_O2maxHC.
    (12) Check the zero response of the FID analyzer using the zero gas
used during emission testing. If the mean

[[Page 25312]]

zero response of 30 seconds of stabilized sample data is within &plusmn;0.5% of
the span reference value used in paragraph (d)(5) of this
section, then proceed to the next step; otherwise restart the procedure
at paragraph (d)(4) of this section.
    (13) Calculate the percent difference between x_O2maxHC
and its reference gas concentration. Calculate the percent difference
between x_O2avgHC and its reference gas concentration.
Calculate the percent difference between x_O2minHC and its
reference gas concentration. Determine the maximum percent difference
of the three. This is the O₂ interference.
    (14) If the O₂ interference is within &plusmn;2%,
the FID passes the O₂ interference verification; otherwise
perform one or more of the following to address the deficiency:
    (i) Repeat the verification to determine if a mistake was made
during the procedure.
    (ii) Select zero and span gases for emission testing that contain
higher or lower O₂ concentrations and repeat the verification.
    (iii) Adjust FID burner air, fuel, and sample flow rates. Note that
if you adjust these flow rates on a THC FID to meet the O₂
interference verification, you have reset RF_CH4 for the next
RF_CH4 verification according to Sec.  1065.360. Repeat the
O₂ interference verification after adjustment and determine RF_CH4.
    (iv) Repair or replace the FID and repeat the O₂
interference verification.
    (v) Demonstrate that the deficiency does not adversely affect your
ability to demonstrate compliance with the applicable emission standards.

• 87. Section 1065.365 is revised to read as follows:

Sec.  1065.365  Nonmethane cutter penetration fractions.

    (a) Scope and frequency. If you use a FID analyzer and a nonmethane
cutter (NMC) to measure methane (CH₄), determine the
nonmethane cutter's penetration fractions of methane, PF_CH4,
and ethane, PF_C2H6. As detailed in this section, these
penetration fractions may be determined as a combination of NMC
penetration fractions and FID analyzer response factors, depending on
your particular NMC and FID analyzer configuration. Perform this
verification after installing the nonmethane cutter. Repeat this
verification within 185 days of testing to verify that the catalytic
activity of the cutter has not deteriorated. Note that because
nonmethane cutters can deteriorate rapidly and without warning if they
are operated outside of certain ranges of gas concentrations and
outside of certain temperature ranges, good engineering judgment may
dictate that you determine a nonmethane cutter's penetration fractions
more frequently.
    (b) Measurement principles. A nonmethane cutter is a heated
catalyst that removes nonmethane hydrocarbons from an exhaust sample
stream before the FID analyzer measures the remaining hydrocarbon
concentration. An ideal nonmethane cutter would have a methane
penetration fraction, PF_CH4, of 1.000, and the penetration
fraction for all other nonmethane hydrocarbons would be 0.000, as
represented by PF_C2H6. The emission calculations in Sec. 
1065.660 use the measured values from this verification to account for
less than ideal NMC performance.
    (c) System requirements. We do not limit NMC penetration fractions
to a certain range. However, we recommend that you optimize a
nonmethane cutter by adjusting its temperature to achieve a
PF_CH4 >0.85 and a PF_C2H6 <0.02, as determined by
paragraphs (d), (e), or (f) of this section, as applicable. If we use a
nonmethane cutter for testing, it will meet this recommendation. If
adjusting NMC temperature does not result in achieving both of these
specifications simultaneously, we recommend that you replace the
catalyst material. Use the most recently determined penetration values
from this section to calculate HC emissions according to Sec.  1065.660
and Sec.  1065.665 as applicable.
    (d) Procedure for a FID calibrated with the NMC. The method
described in this paragraph (d) is recommended over the procedures
specified in paragraphs (e) and (f) of this section. If your FID
arrangement is such that a FID is always calibrated to measure
CH₄ with the NMC, then span that FID with the NMC using a
CH₄ span gas, set the product of that FID's CH₄
response factor and CH₄ penetration fraction,
RFPF_CH4[NMC-FID], equal to 1.0 for all emission
calculations, and determine its combined ethane
(C₂H₆) response factor and penetration fraction,
RFPF_{C2H6[NMC-FID]} as follows:
    (1) Select a CH₄ gas mixture and a
C₂H₆ analytical gas mixture and ensure that both
mixtures meet the specifications of Sec.  1065.750. Select a
CH₄ concentration that you would use for spanning the FID
during emission testing and select a C₂H₆
concentration that is typical of the peak NMHC concentration expected
at the hydrocarbon standard or equal to THC analyzer's span value.
    (2) Start, operate, and optimize the nonmethane cutter according to
the manufacturer's instructions, including any temperature optimization.
    (3) Confirm that the FID analyzer meets all the specifications of
Sec.  1065.360.
    (4) Start and operate the FID analyzer according to the
manufacturer's instructions.
    (5) Zero and span the FID with the cutter and use CH₄
span gas to span the FID with the cutter. Note that you must span the
FID on a C1 basis. For example, if your span gas has a CH₄
reference value of 100 &mu;mol/mol, the correct FID response to that
span gas is 100 &mu;mol/mol because there is one carbon atom per
CH₄ molecule.
    (6) Introduce the C₂H₆ analytical gas mixture
upstream of the nonmethane cutter.
    (7) Allow time for the analyzer response to stabilize.
Stabilization time may include time to purge the nonmethane cutter and
to account for the analyzer's response.
    (8) While the analyzer measures a stable concentration, record 30
seconds of sampled data. Calculate the arithmetic mean of these data points.
    (9) Divide the mean by the reference value of
C₂H₆, converted to a C₁ basis. The
result is the C₂H₆ combined response factor and
penetration fraction, RFPF_{C2H6[NMC-FID]}. Use this combined
response factor and penetration fraction and the product of the
CH₄ response factor and CH₄ penetration fraction,
RFPF_CH4[NMC-FID], set to 1.0 in emission calculations
according to Sec.  1065.660(b)(2)(i) or Sec.  1065.665, as applicable.
    (e) Procedure for a FID calibrated with propane, bypassing the NMC.
If you use a FID with an NMC that is calibrated with propane,
C₃H₈, by bypassing the NMC, determine its
penetration fractions, PF_{C2H6[NMC-FID]} and
PF_CH4[NMC-FID], as follows:
    (1) Select CH₄ and C₂H₆ analytical
gas mixtures that meet the specifications of Sec.  1065.750 with the
CH₄ concentration typical of its peak concentration expected
at the hydrocarbon standard and the C₂H₆
concentration typical of the peak total hydrocarbon (THC) concentration
expected at the hydrocarbon standard or the THC analyzer span value.
    (2) Start and operate the nonmethane cutter according to the
manufacturer's instructions, including any temperature optimization.
    (3) Confirm that the FID analyzer meets all the specifications of
Sec.  1065.360.
    (4) Start and operate the FID analyzer according to the
manufacturer's instructions.
    (5) Zero and span the FID as you would during emission testing.
Span the FID by bypassing the cutter and by

[[Page 25313]]

using C₃H₈ span gas to span the FID. Note that
you must span the FID on a C₁ basis. For example, if your
span gas has a propane reference value of 100 &mu;mol/mol, the correct
FID response to that span gas is 300 &mu;mol/mol because there are
three carbon atoms per C₃H₈ molecule.
    (6) Introduce the C₂H₆ analytical gas mixture
upstream of the nonmethane cutter at the same point the zero gas was
introduced.
    (7) Allow time for the analyzer response to stabilize.
Stabilization time may include time to purge the nonmethane cutter and
to account for the analyzer's response.
    (8) While the analyzer measures a stable concentration, record 30
seconds of sampled data. Calculate the arithmetic mean of these data points.
    (9) Reroute the flow path to bypass the nonmethane cutter,
introduce the C₂H₆ analytical gas mixture to the
bypass, and repeat the steps in paragraphs (e)(7) through (8) of this
section.
    (10) Divide the mean C₂H₆ concentration
measured through the nonmethane cutter by the mean concentration
measured after bypassing the nonmethane cutter. The result is the
C₂H₆ penetration fraction,
PF_{C2H6[NMC-FID]}. Use this penetration fraction according to
Sec.  1065.660(b)(2)(ii) or Sec.  1065.665, as applicable.
    (11) Repeat the steps in paragraphs (e)(6) through (10) of this
section, but with the CH₄ analytical gas mixture instead of
C₂H₆. The result will be the CH₄
penetration fraction, PF_CH4[NMC-FID]. Use this penetration
fraction according to Sec.  1065.660(b)(2)(ii) or Sec.  1065.665, as
applicable.
    (f) Procedure for a FID calibrated with methane, bypassing the NMC.
If you use a FID with an NMC that is calibrated with methane,
CH₄, by bypassing the NMC, determine its combined ethane
(C₂H₆) response factor and penetration fraction,
RFPF_{C2H6[NMC-FID]}, as well as its CH₄ penetration
fraction, PF_CH4[NMC-FID], as follows:
    (1) Select CH₄ and C₂H₆ analytical
gas mixtures that meet the specifications of Sec.  1065.750, with the
CH₄ concentration typical of its peak concentration expected
at the hydrocarbon standard and the C₂H₆
concentration typical of the peak total hydrocarbon (THC) concentration
expected at the hydrocarbon standard or the THC analyzer span value.
    (2) Start and operate the nonmethane cutter according to the
manufacturer's instructions, including any temperature optimization.
    (3) Confirm that the FID analyzer meets all the specifications of
Sec.  1065.360.
    (4) Start and operate the FID analyzer according to the
manufacturer's instructions.
    (5) Zero and span the FID as you would during emission testing.
Span the FID with CH₄ span gas by bypassing the cutter. Note
that you must span the FID on a C₁ basis. For example, if
your span gas has a methane reference value of 100 &mu;mol/mol, the
correct FID response to that span gas is 100 &mu;mol/mol because there
is one carbon atom per CH₄ molecule.
    (6) Introduce the C₂H₆ analytical gas mixture
upstream of the nonmethane cutter at the same point the zero gas was
introduced.
    (7) Allow time for the analyzer response to stabilize.
Stabilization time may include time to purge the nonmethane cutter and
to account for the analyzer's response.
    (8) While the analyzer measures a stable concentration, record 30
seconds of sampled data. Calculate the arithmetic mean of these data
points.
    (9) Reroute the flow path to bypass the nonmethane cutter,
introduce the C₂H₆ analytical gas mixture to the
bypass, and repeat the steps in paragraphs (e)(7) and (8) of this section.
    (10) Divide the mean C₂H₆ concentration
measured through the nonmethane cutter by the mean concentration
measured after bypassing the nonmethane cutter. The result is the
C₂H₆ combined response factor and penetration
fraction, RFPF_{C2H6[NMC-FID]}. Use this combined response
factor and penetration fraction according to Sec.  1065.660(b)(2)(iii)
or Sec.  1065.665, as applicable.
    (11) Repeat the steps in paragraphs (e)(6) through (10) of this
section, but with the CH₄ analytical gas mixture instead of
C₂H₆. The result will be the CH₄
penetration fraction, PF_CH4[NMC-FID]. Use this penetration
fraction according to Sec.  1065.660(b)(2)(iii) or Sec.  1065.665, as
applicable.

• 88. Section 1065.370 is amended by revising paragraphs (d), (e), and
(g)(1) to read as follows:

Sec.  1065.370  CLD CO2 and H2O quench verification.

* * * * *
    (d) CO₂ quench verification procedure. Use the following
method to determine CO₂ quench, or use good engineering
judgment to develop a different protocol:
    (1) Use PTFE or stainless steel tubing to make necessary connections.
    (2) Connect a pressure-regulated CO₂ span gas to the
port of a gas divider that meets the specifications in Sec.  1065.248
at the appropriate time. Use a CO₂ span gas that meets the
specifications of Sec.  1065.750 and attempt to use a concentration
that is approximately twice the maximum CO₂ concentration
expected to enter the CLD sample port during testing, if available.
    (3) Connect a pressure-regulated purified N₂ gas to the
port of a gas divider that meets the specifications in Sec.  1065.248
at the appropriate time. Use a purified N₂ gas that meets
the specifications of Sec.  1065.750.
    (4) Connect a pressure-regulated NO span gas to the port of the gas
divider that meets the specifications in Sec.  1065.248. Use an NO span
gas that meets the specifications of Sec.  1065.750. Attempt to use an
NO concentration that is approximately twice the maximum NO
concentration expected during testing, if available.
    (5) Configure the gas divider such that nearly equal amounts of the
span gas and balance gas are blended with each other. Apply viscosity
corrections as necessary to appropriately ensure correct gas division.
    (6) While flowing NO and CO₂ through the gas divider,
stabilize the CO₂ concentration downstream of the gas
divider and measure the CO₂ concentration with an NDIR
analyzer that has been prepared for emission testing. You may
alternatively determine the CO₂ concentration from the gas
divider cut-point, applying viscosity correction as necessary to ensure
accurate gas division. Record this concentration, x_CO2meas,
and use it in the quench verification calculations in Sec.  1065.675.
    (7) Measure the NO concentration downstream of the gas divider. If
the CLD has an operating mode in which it detects NO-only, as opposed
to total NO_X, operate the CLD in the NO-only operating mode.
Record this concentration, x_NO,CO2, and use it in the quench
verification calculations in Sec.  1065.675.
    (8) Switch the flow of CO₂ off and start the flow of
100% purified N₂ to the inlet port of the gas divider.
Monitor the CO₂ at the gas divider's outlet until its
concentration stabilizes at zero.
    (9) Measure NO concentration at the gas divider's outlet. Record
this value, x_NO,N2, and use it in the quench verification
calculations in Sec.  1065.675.
    (10) Use the values recorded according to this paragraph (d) of
this section and paragraph (e) of this section to calculate quench as
described in Sec.  1065.675.
    (e) H2O quench verification procedure. Use the following method to
determine H2O quench, or use good

[[Page 25314]]

engineering judgment to develop a different protocol:
    (1) Use PTFE or stainless steel tubing to make necessary connections.
    (2) If the CLD has an operating mode in which it detects NO-only,
as opposed to total NO_X, operate the CLD in the NO-only
operating mode.
    (3) Measure an NO calibration span gas that meets the
specifications of Sec.  1065.750 and is near the maximum concentration
expected during testing. Record this concentration, xNOdry.
    (4) Humidify the NO span gas by bubbling it through distilled water
in a sealed vessel. If the sample is not passed through a dryer,
control the vessel temperature to generate an H2O level at least as
high as the maximum expected during testing. If the sample is passed
through a dryer during testing, control the vessel temperature to
generate an H₂O level at least as high as the level
determined in Sec.  1065.145(d)(2). We recommend that you humidify the
gas to the highest sample dewpoint that you estimate at the CLD inlet
during emission sampling. Regardless of the humidity during this test,
the quench verification calculations in Sec.  1065.675 scale the
recorded quench to the highest dewpoint expected for flow entering the
CLD sample port during emission sampling.
    (5) Introduce the humidified NO test gas into the sample system.
You may introduce it downstream of any sample dryer, if one is used
during testing.
    (6) Measure the humidified gas dewpoint, Tdew, and pressure,
ptotal, as close as possible to the analyzer inlet.
    (7) Downstream of the vessel, maintain the humidified NO test gas
temperature at least 5 [deg]C above its dewpoint.
    (8) Allow time for the analyzer response to stabilize.
Stabilization time may include time to purge the transfer line and to
account for analyzer response.
    (9) While the analyzer measures the sample's concentration, record
the analyzer's output for 30 seconds. Calculate the arithmetic mean of
these data. This mean is xNOmeas.
    (10) Set xNOwet equal to xNOmeas from paragraph (e)(9) of this section.
    (11) Use xNOwet to calculate the quench according to Sec.  1065.675.
* * * * *
    (g) * * *
    (1) You may omit this verification if you can show by engineering
analysis that for your NO_X sampling system and your emission
calculations procedures, the combined CO2 and H2O interference for your
NO_X CLD analyzer always affects your brake-specific
NO_X emission results within no more than &plusmn;1.0% of
the applicable NO_X standard.
* * * * *

• 89. Section 1065.372 is amended by revising paragraphs (d)(7) and
(e)(1) to read as follows:

Sec.  1065.372  NDUV analyzer HC and H₂O interference verification.

* * * * *
    (d) * * *
    (7) Multiply this difference by the ratio of the flow-weighted mean
HC concentration expected at the standard to the HC concentration
measured during the verification. The analyzer meets the interference
verification of this section if this result is within &plusmn;2% of
the NO_X concentration expected at the standard.
    (e) * * *
    (1) You may omit this verification if you can show by engineering
analysis that for your NO_X sampling system and your emission
calculations procedures, the combined HC and H₂O
interference for your NO_X NDUV analyzer always affects your
brake-specific NO_X emission results by less than 0.5% of the
applicable NO_X standard.
* * * * *

• 90. Section 1065.376 is revised to read as follows:

Sec.  1065.376  Chiller NO2 penetration.

    (a) Scope and frequency. If you use a chiller to dry a sample
upstream of a NO_X measurement instrument, but you don't use
an NO2-to-NO converter upstream of the chiller, you must perform this
verification for chiller NO2 penetration. Perform this verification
after initial installation and after major maintenance.
    (b) Measurement principles. A chiller removes water, which can
otherwise interfere with a NO_X measurement. However, liquid
water remaining in an improperly designed chiller can remove NO2 from
the sample. If a chiller is used without an NO2-to-NO converter upstream,
it could remove NO2 from the sample prior NO_X measurement.
    (c) System requirements. A chiller must allow for measuring at
least 95% of the total NO2 at the maximum expected concentration of NO2.
    (d) Procedure. Use the following procedure to verify chiller
performance:
    (1) Instrument setup. Follow the analyzer and chiller
manufacturers' start-up and operating instructions. Adjust the analyzer
and chiller as needed to optimize performance.
    (2) Equipment setup and data collection. (i) Zero and span the
total NO_X gas analyzer(s) as you would before emission testing.
    (ii) Select an NO2 calibration gas, balance gas of dry air, that
has an NO2 concentration within &plusmn;5% of the maximum NO2
concentration expected during testing.
    (iii) Overflow this calibration gas at the gas sampling system's
probe or overflow fitting. Allow for stabilization of the total
NO_X response, accounting only for transport delays and
instrument response.
    (iv) Calculate the mean of 30 seconds of recorded total
NO_X data and record this value as _NOXref.
    (v) Stop flowing the NO2 calibration gas.
    (vi) Next saturate the sampling system by overflowing a dewpoint
generator's output, set at a dewpoint of 50 [deg]C, to the gas sampling
system's probe or overflow fitting. Sample the dewpoint generator's
output through the sampling system and chiller for at least 10 minutes
until the chiller is expected to be removing a constant rate of water.
    (vii) Immediately switch back to overflowing the NO2 calibration
gas used to establish x_NOxref. Allow for stabilization of
the total NO_X response, accounting only for transport delays
and instrument response. Calculate the mean of 30 seconds of recorded
total NO_X data and record this value as x_NOxmeas.
    (viii) Correct x_NOxmeas to x_NOxdry based upon
the residual water vapor that passed through the chiller at the
chiller's outlet temperature and pressure.
    (3) Performance evaluation. If x_NOxdry is less than 95%
of x_NOxref, repair or replace the chiller.
    (e) Exceptions. The following exceptions apply:
    (1) You may omit this verification if you can show by engineering
analysis that for your NO_X sampling system and your emission
calculations procedures, the chiller always affects your brake-specific
NO_X emission results by less than 0.5% of the applicable
NO_X standard.
    (2) You may use a chiller that you determine does not meet this
verification, as long as you try to correct the problem and the
measurement deficiency does not adversely affect your ability to show
that engines comply with all applicable emission standards.

• 91. Section 1065.378 is amended by revising paragraphs (d) and (e)(1)
to read as follows:

Sec.  1065.378  NO2-to-NO converter conversion verification.

* * * * *
    (d) Procedure. Use the following procedure to verify the
performance of a NO2-to-NO converter:

[[Page 25315]]

    (1) Instrument setup. Follow the analyzer and NO2-to-NO converter
manufacturers' start-up and operating instructions. Adjust the analyzer
and converter as needed to optimize performance.
    (2) Equipment setup. Connect an ozonator's inlet to a zero-air or
oxygen source and connect its outlet to one port of a three-way tee
fitting. Connect an NO span gas to another port, and connect the NO2-
to-NO converter inlet to the last port.
    (3) Adjustments and data collection. Perform this check as follows:
    (i) Set ozonator air off, turn ozonator power off, and set the
analyzer to NO mode. Allow for stabilization, accounting only for
transport delays and instrument response.
    (ii) Use an NO concentration that is representative of the peak
total NO_X concentration expected during testing. The NO2
content of the gas mixture shall be less than 5% of the NO
concentration. Record the concentration of NO by calculating the mean
of 30 seconds of sampled data from the analyzer and record this value
as xNOref.
    (iii) Turn on the ozonator O₂ supply and adjust the
O₂ flow rate so the NO indicated by the analyzer is about 10
percent less than x_NOref. Record the concentration of NO by
calculating the mean of 30 seconds of sampled data from the analyzer
and record this value as x_NO+O2mix.
    (iv) Switch the ozonator on and adjust the ozone generation rate so
the NO measured by the analyzer is 20 percent of x_NOref,
while maintaining at least 10 percent unreacted NO. Record the
concentration of NO by calculating the mean of 30 seconds of sampled
data from the analyzer and record this value as x_NOmeas.
    (v) Switch the NO_X analyzer to NO_X mode and
measure total NO_X. Record the concentration of
NO_X by calculating the mean of 30 seconds of sampled data
from the analyzer and record this value as x_NOxmeas.
    (vi) Switch off the ozonator but maintain gas flow through the
system. The NO_X analyzer will indicate the NO_X in
the NO + O₂ mixture. Record the concentration of
NO_X by calculating the mean of 30 seconds of sampled data
from the analyzer and record this value as x_NOx+O2mix.
    (vii) Turn off the ozonator O₂ supply. The
NO_X analyzer will indicate the NO_X in the
original NO-in-N₂ mixture. Record the concentration of
NO_X by calculating the mean of 30 seconds of sampled data
from the analyzer and record this value as x_NOxref. This
value should be no more than 5 percent above the x_NOref value.
    (4) Performance evaluation. Calculate the efficiency of the
NO_X converter efficiency by substituting the concentrations
obtained into the following equation:
[GRAPHIC] [TIFF OMITTED] TR06MY08.021

    (5) If the result is less than 95%, repair or replace the
NO₂-to-NO converter.
    (e) * * *
    (1) You may omit this verification if you can show by engineering
analysis that for your NO_X sampling system and your emission
calculations procedures, the converter always affects your brake-
specific NO_X emission results by less than 0.5% of the
applicable NO_X standard.
* * * * *

• 92. Section 1065.390 is revised to read as follows:

Sec.  1065.390  PM balance verifications and weighing process verification.

    (a) Scope and frequency. This section describes three verifications.
    (1) Independent verification of PM balance performance within 370
days before weighing any filter.
    (2) Zero and span the balance within 12 h before weighing any filter.
    (3) Verify that the mass determination of reference filters before
and after a filter weighing session are less than a specified tolerance.
    (b) Independent verification. Have the balance manufacturer (or a
representative approved by the balance manufacturer) verify the balance
performance within 370 days of testing.
    (c) Zeroing and spanning. You must verify balance performance by
zeroing and spanning it with at least one calibration weight, and any
weights you use must that meet the specifications in Sec.  1065.790 to
perform this verification.
    (1) Use a manual procedure in which you zero the balance and span
the balance with at least one calibration weight. If you normally use
mean values by repeating the weighing process to improve the accuracy
and precision of PM measurements, use the same process to verify
balance performance.
    (2) You may use an automated procedure to verify balance
performance. For example many balances have internal calibration
weights that are used automatically to verify balance performance. Note
that if you use internal balance weights, the weights must meet the
specifications in Sec.  1065.790 to perform this verification.
    (d) Reference sample weighing. Verify all mass readings during a
weighing session by weighing reference PM sample media (e.g. filters)
before and after a weighing session. A weighing session may be as short
as desired, but no longer than 80 hours, and may include both pre-test
and post-test mass readings. We recommend that weighing sessions be
eight hours or less. Successive mass determinations of each reference
PM sample media (e.g., filter) must return the same value within
&plusmn;10 &mu;g or &plusmn;10% of the net PM mass expected at the
standard (if known), whichever is higher. If successive reference PM
sample media (e.g. filter) weighing events fail this criterion,
invalidate all individual test media (e.g., filter) mass readings
occurring between the successive reference media (e.g., filter) mass
determinations. You may reweigh these media (e.g. filter) in another
weighing session. If you invalidate a pre-test media (e.g. filter) mass
determination, that test interval is void. Perform this verification as
follows:
    (1) Keep at least two samples of unused PM sample media (e.g.,,
filters) in the PM-stabilization environment. Use these as references.
If you collect PM with filters, select unused filters of the same
material and size for use as references. You may periodically replace
references, using good engineering judgment.
    (2) Stabilize references in the PM stabilization environment.
Consider references stabilized if they have been in the PM-
stabilization environment for a minimum of 30 min, and the PM-
stabilization environment has been within the specifications of Sec. 
1065.190(d) for at least the preceding 60 min.
    (3) Exercise the balance several times with a reference sample. We
recommend weighing ten samples without recording the values.
    (4) Zero and span the balance. Using good engineering judgment,
place a test mass such as a calibration weight on the balance, then
remove it. After spanning,

[[Page 25316]]

confirm that the balance returns to a zero reading within the normal
stabilization time.
    (5) Weigh each of the reference media (e.g., filters) and record
their masses. We recommend using substitution weighing as described in
Sec.  1065.590(j). If you normally use mean values by repeating the
weighing process to improve the accuracy and precision of the reference
media (e.g., filter) mass, you must use mean values of sample media
(e.g., filter) masses.
    (6) Record the balance environment dewpoint, ambient temperature,
and atmospheric pressure.
    (7) Use the recorded ambient conditions to correct results for
buoyancy as described in Sec.  1065.690. Record the buoyancy-corrected
mass of each of the references.
    (8) Subtract each reference media's (e.g., filter's) buoyancy-
corrected reference mass from its previously measured and recorded
buoyancy-corrected mass.
    (9) If any of the reference filters' observed mass changes by more
than that allowed under this paragraph, you must invalidate all PM mass
determinations made since the last successful reference media (e.g.,
filter) mass validation. You may discard reference PM media (e.g.,
filters) if only one one of the filter's mass changes by more than the
allowable amount and you can positively identify a special cause for
that filter's mass change that would not have affected other in-process
filters. Thus, the validation can be considered a success. In this
case, you do not have to include the contaminated reference media when
determining compliance with paragraph (d)(10) of this section, but the
affected reference filter must be immediately discarded and replaced
prior to the next weighing session.
    (10) If any of the reference masses change by more than that
allowed under this paragraph (d), invalidate all PM results that were
determined between the two times that the reference masses were
determined. If you discarded reference PM sample media according to
paragraph (d)(9) of this section, you must still have at least one
reference mass difference that meets the criteria in this paragraph
(d). Otherwise, you must invalidate all PM results that were determined
between the two times that the reference media (e.g., filters) masses
were determined.

Subpart E--[Amended]

• 93. Section 1065.405 is revised to read as follows:

Sec.  1065.405  Test engine preparation and maintenance.

    This part 1065 describes how to test engines for a variety of
purposes, including certification testing, production-line testing, and
in-use testing. Depending on which type of testing is being conducted,
different preparation and maintenance requirements apply for the test
engine.
    (a) If you are testing an emission-data engine for certification,
make sure it is built to represent production engines. This includes
governors that you normally install on production engines. Production
engines should also be tested with their installed governors. If you do
not install governors on production engines, simulate a governor that
is representative of a governor that others will install on your
production engines.
    (b) Testing generally occurs only after the test engine has
undergone a stabilization step (or in-use operation). If the engine has
not already been stabilized, run the test engine, with all emission
control systems operating, long enough to stabilize emission levels.
Note that you must generally use the same stabilization procedures for
emission-data engines for which you apply the same deterioration
factors so low-hour emission-data engines are consistent with the low-
hour engine used to develop the deterioration factor.
    (1) Unless otherwise specified in the standard-setting part, you
may consider emission levels stable without measurement after 50 h of
operation. If the engine needs less operation to stabilize emission
levels, record your reasons and the methods for doing this, and give us
these records if we ask for them. If the engine will be tested for
certification as a low-hour engine, see the standard-setting part for
limits on testing engines to establish low-hour emission levels.
    (2) You may stabilize emissions from a catalytic exhaust
aftertreatment device by operating it on a different engine, consistent
with good engineering judgment. Note that good engineering judgment
requires that you consider both the purpose of the test and how your
stabilization method will affect the development and application of
deterioration factors. For example, this method of stabilization is
generally not appropriate for production engines. We may also allow you
to stabilize emissions from a catalytic exhaust aftertreatment device
by operating it on an engine-exhaust simulator.
    (c) Record any maintenance, modifications, parts changes,
diagnostic or emissions testing and document the need for each event.
You must provide this information if we request it.
    (d) For accumulating operating hours on your test engines, select
engine operation that represents normal in-use operation for the engine
family.
    (e) If your engine will be used in a vehicle equipped with a
canister for storing evaporative hydrocarbons for eventual combustion
in the engine and the test sequence involves a cold-start or hot-start
duty cycle, attach a canister to the engine before running an emission
test. You may omit using an evaporative canister for any hot-stabilized
duty cycles. You may request to omit using an evaporative canister
during testing if you can show that it would not affect your ability to
show compliance with the applicable emission standards. You may operate
the engine without an installed canister for service accumulation.
Prior to an emission test, use the following steps to attach a canister
to your engine:
    (1) Use a canister and plumbing arrangement that represents the in-
use configuration of the largest capacity canister in all expected
applications.
    (2) Use a canister that is fully loaded with fuel vapors.
    (3) Connect the canister's purge port to the engine.
    (4) Plug the canister port that is normally connected to the fuel tank.

• 94. Section 1065.410 is amended by revising paragraphs (c) and (d) to
read as follows:

Sec.  1065.410  Maintenance limits for stabilized test engines.

* * * * *
    (c) Keep a record of the inspection and update your application to
document any changes as a result of the inspection. You may use
equipment, instruments, or engineering grade tools to identify bad
engine components. Any equipment, instruments, or tools used for
scheduled maintenance on emission data engines must be representative
of what is planned to be available to dealerships and other service outlets.
    (d) If we determine that a part failure, system malfunction, or
associated repairs have made the engine's emission controls
unrepresentative of production engines, you may no longer use it as an
emission-data engine. Also, if your test engine has a major mechanical
failure that requires you to take it apart, you may no longer use it as
an emission-data engine.
* * * * *

• 95. Section 1065.415 is amended by revising the introductory text and
removing paragraph (a)(3) to read as follows:

[[Page 25317]]

Sec.  1065.415  Durability demonstration.

    If the standard-setting part requires durability testing, you must
accumulate service in a way that represents how you expect the engine
to operate in use. You may accumulate service hours using an
accelerated schedule, such as through continuous operation or by using
duty cycles that are more aggressive than in-use operation, subject to
any pre-approval requirements established in the applicable standard-
setting part.
* * * * *

• 96. The heading to subpart F of part 1065 is revised to read as follows:

Subpart F--Performing an Emission Test Over Specified Duty Cycles

    97. Section 1065.501 is amended by revising paragraphs (a)
introductory text, (a)(1), and (b) to read as follows:

Sec.  1065.501  Overview.

    (a) Use the procedures detailed in this subpart to measure engine
emissions over a specified duty cycle. Refer to subpart J of this part
for field test procedures that describe how to measure emissions during
in-use engine operation. This section describes how to:
    (1) Map your engine, if applicable, by recording specified speed
and torque data, as measured from the engine's primary output shaft.
* * * * *
    (b) An emission test generally consists of measuring emissions and
other parameters while an engine follows one or more duty cycles that
are specified in the standard-setting part. There are two general types
of duty cycles:
    (1) Transient cycles. Transient duty cycles are typically specified
in the standard-setting part as a second-by-second sequence of speed
commands and normalized torque (or power) commands. Operate an engine
over a transient cycle such that the speed and torque of the engine's
primary output shaft follows the target values. Proportionally sample
emissions and other parameters and use the calculations in subpart G of
this part to calculate emissions. Start a transient test according to
the standard-setting part, as follows:
    (i) A cold-start transient cycle where you start to measure
emissions just before starting an engine that has not been warmed up.
    (ii) A hot-start transient cycle where you start to measure
emissions just before starting a warmed-up engine.
    (iii) A hot running transient cycle where you start to measure
emissions after an engine is started, warmed up, and running.
    (2) Steady-state cycles. Steady-state duty cycles are typically
specified in the standard-setting part as a list of discrete operating
points (modes or notches), where each operating point has one value of
a normalized speed command and one value of a normalized torque (or
power) command. Ramped-modal cycles for steady-state testing also list
test times for each mode and transition times between modes where speed
and torque are linearly ramped between modes, even for cycles with %
power. Start a steady-state cycle as a hot running test, where you
start to measure emissions after an engine is started, warmed up and
running. You may run a steady-state duty cycle as a discrete-mode cycle
or a ramped-modal cycle, as follows:
    (i) Discrete-mode cycles. Before emission sampling, stabilize an
engine at the first discrete mode. Sample emissions and other
parameters for that mode and then stop emission sampling. Record mean
values for that mode, and then stabilize the engine at the next mode.
Continue to sample each mode discretely and calculate weighted emission
results according to the standard-setting part.
    (ii) Ramped-modal cycles. Perform ramped-modal cycles similar to
the way you would perform transient cycles, except that ramped-modal
cycles involve mostly steady-state engine operation. Generate a ramped-
modal duty cycle as a sequence of second-by-second (1 Hz) reference
speed and torque points. Run the ramped-modal duty cycle in the same
manner as a transient cycle and use the 1 Hz reference speed and torque
values to validate the cycle, even for cycles with % power.
Proportionally sample emissions and other parameters during the cycle
and use the calculations in subpart G of this part to calculate emissions.
* * * * *

• 98. Section 1065.510 is revised to read as follows:

Sec.  1065.510  Engine mapping.

    (a) Applicability, scope, and frequency. An engine map is a data
set that consists of a series of paired data points that represent the
maximum brake torque versus engine speed, measured at the engine's
primary output shaft. Map your engine if the standard-setting part
requires engine mapping to generate a duty cycle for your engine
configuration. Map your engine while it is connected to a dynamometer
or other device that can absorb work output from the engine's primary
output shaft according to Sec.  1065.110. Configure any auxiliary work
inputs and outputs such as hybrid, turbo-compounding, or thermoelectric
systems to represent their in-use configurations, and use the same
configuration for emission testing. See Figure 1 of Sec.  1065.210.
This may involve configuring initial states of charge and rates and
times of auxiliary-work inputs and outputs. We recommend that you
contact the Designated Compliance Officer before testing to determine
how you should configure any auxiliary-work inputs and outputs. Use the
most recent engine map to transform a normalized duty cycle from the
standard-setting part to a reference duty cycle specific to your
engine. Normalized duty cycles are specified in the standard-setting
part. You may update an engine map at any time by repeating the engine-
mapping procedure. You must map or re-map an engine before a test if
any of the following apply:
    (1) If you have not performed an initial engine map.
    (2) If the atmospheric pressure near the engine's air inlet is not
within &plusmn; 5 kPa of the atmospheric pressure recorded at the
time of the last engine map.
    (3) If the engine or emission-control system has undergone changes
that might affect maximum torque performance. This includes changing
the configuration of auxiliary work inputs and outputs.
    (4) If you capture an incomplete map on your first attempt or you
do not complete a map within the specified time tolerance. You may
repeat mapping as often as necessary to capture a complete map within
the specified time.
    (b) Mapping variable-speed engines. Map variable-speed engines as
follows:
    (1) Record the atmospheric pressure.
    (2) Warm up the engine by operating it. We recommend operating the
engine at any speed and at approximately 75% of its expected maximum
power. Continue the warm-up until the engine coolant, block, or head
absolute temperature is within &plusmn; 2% of its mean value for at
least 2 min or until the engine thermostat controls engine temperature.
    (3) Operate the engine at its warm idle speed.
    (i) For engines with a low-speed governor, set the operator demand
to minimum, use the dynamometer or other loading device to target a
torque of zero on the engine's primary output shaft, and allow the
engine to govern the speed. Measure this warm idle speed; we recommend
recording at least 30

[[Page 25318]]

values of speed and using the mean of those values.
    (ii) For engines without a low-speed governor, set the dynamometer
to target a torque of zero on the engine's primary output shaft, and
manipulate the operator demand to control the speed to target the
manufacturer-declared value for the lowest engine speed possible with
minimum load (also known as manufacturer-declared warm idle speed).
    (iii) For all variable-speed engines (with or without a low-speed
governor), if a nonzero idle torque is representative of in-use
operation, you may target the manufacturer-declared idle torque. If you
measure the warm idle speed with the manufacturer-declared torque at
this step, you may omit the speed measurement in paragraph (b)(6) of
this section.
    (4) Set operator demand to maximum and control engine speed at (95
&plusmn; 1) % of its warm idle speed determined above for at least
15 seconds. For engines with reference duty cycles whose lowest speed
is greater than warm idle speed, you may start the map at (95 &plusmn; 1) %
of the lowest reference speed.
    (5) Perform one of the following:
    (i) For any engine subject only to steady-state duty cycles (i.e.,
discrete-mode or ramped-modal), you may perform an engine map by using
discrete speeds. Select at least 20 evenly spaced setpoints between
warm idle and the highest speed above maximum mapped power at which (50
to 75)% of maximum power occurs. If this highest speed is unsafe or
unrepresentative (e.g., for ungoverned engines), use good engineering
judgment to map up to the maximum safe speed or the maximum
representative speed. At each setpoint, stabilize speed and allow
torque to stabilize. Record the mean speed and torque at each setpoint.
We recommend that you stabilize an engine for at least 15 seconds at
each setpoint and record the mean feedback speed and torque of the last
(4 to 6) seconds. Use linear interpolation to determine intermediate
speeds and torques. Use this series of speeds and torques to generate
the power map as described in paragraph (e) of this section.
    (ii) For any variable-speed engine, you may perform an engine map
by using a continuous sweep of speed by continuing to record the mean
feedback speed and torque at 1 Hz or more frequently and increasing
speed at a constant rate such that it takes (4 to 6) min to sweep from
95% of warm idle to the highest speed above maximum power at which (50
to 75)% of maximum power occurs. If this highest speed is unsafe or
unrepresentative (e.g., for ungoverned engines), use good engineering
judgment to map up to the maximum safe speed or the maximum
representative speed. Stop recording after you complete the sweep. From
the series of mean speed and maximum torque values, use linear
interpolation to determine intermediate values. Use this series of
speeds and torques to generate the power map as described in paragraph
(e) of this section.
    (6) For engines with a low-speed governor, if a nonzero idle torque
is representative of in-use operation, operate the engine at warm idle
with the manufacturer-declared idle torque. Set the operator demand to
minimum, use the dynamometer to target the declared idle torque, and
allow the engine to govern the speed. Measure this speed and use it as
the warm idle speed for cycle generation in Sec.  1065.512. We
recommend recording at least 30 values of speed and using the mean of
those values. You may map the idle governor at multiple load levels and
use this map to determine the measured warm idle speed at the declared
idle torque.
    (c) Negative torque mapping. If your engine is subject to a
reference duty cycle that specifies negative torque values (i.e., engine
motoring), generate a motoring map by any of the following procedures:
    (1) Multiply the positive torques from your map by -40%. Use linear
interpolation to determine intermediate values.
    (2) Map the amount of negative torque required to motor the engine
by repeating paragraph (b) of this section with minimum operator demand.
    (3) Determine the amount of negative torque required to motor the
engine at the following two points near the ends of the engine's speed
range. Operate the engine at these two points at minimum operator
demand. Use linear interpolation to determine intermediate values.
    (i) Low-speed point. For engines without a low-speed governor,
determine the amount of negative torque at warm idle speed. For engines
with a low-speed governor, motor the engine above warm idle speed so
the governor is inactive and determine the amount of negative torque at
that speed.
    (ii) High-speed point. For engines without a high-speed governor,
determine the amount of negative torque at the maximum safe speed or
the maximum representative speed. For engines with a high-speed
governor, determine the amount of negative torque at a speed at or
above n_hi per Sec.  1065.610(c)(2).
    (d) Mapping constant-speed engines. For constant-speed engines,
generate a map as follows:
    (1) Record the atmospheric pressure.
    (2) Warm up the engine by operating it. We recommend operating the
engine at approximately 75% of the engine's expected maximum power.
Continue the warm-up until the engine coolant, block, or head absolute
temperature is within &plusmn;2% of its mean value for at least 2
min or until the engine thermostat controls engine temperature.
    (3) You may operate the engine with a production constant-speed
governor or simulate a constant-speed governor by controlling engine
speed with an operator demand control system described in Sec. 
1065.110. Use either isochronous or speed-droop governor operation, as
appropriate.
    (4) With the governor or simulated governor controlling speed using
operator demand, operate the engine at no-load governed speed (at high
speed, not low idle) for at least 15 seconds.
    (5) Record at 1 Hz the mean of feedback speed and torque. Use the
dynamometer to increase torque at a constant rate. Unless the standard-
setting part specifies otherwise, complete the map such that it takes
(2 to 4) min to sweep from no-load governed speed to the lowest speed
below maximum mapped power at which the engine develops (85-95)% of
maximum mapped power. You may map your engine to lower speeds. Stop
recording after you complete the sweep. Use this series of speeds and
torques to generate the power map as described in paragraph (e) of this
section.
    (e) Power mapping. For all engines, create a power-versus-speed map
by transforming torque and speed values to corresponding power values.
Use the mean values from the recorded map data. Do not use any
interpolated values. Multiply each torque by its corresponding speed
and apply the appropriate conversion factors to arrive at units of
power (kW). Interpolate intermediate power values between these power
values, which were calculated from the recorded map data.
    (f) Measured and declared test speeds and torques. You must select
test speeds and torques for cycle generation as required in this
paragraph (f). ``Measured'' values are either directly measured during
the engine mapping process or they are determined from the engine map.
``Declared'' values are specified by the manufacturer. When both
measured and declared values are available, you may use declared test
speeds and torques instead of measured speeds and torques if they meet
the criteria in this paragraph (f). Otherwise,

[[Page 25319]]

you must use measured speeds and torques derived from the engine map.
    (1) Measured speeds and torques. Determine the applicable speeds
and torques for the duty cycles you will run:
    (i) Measured maximum test speed for variable-speed engines
according to Sec.  1065.610.
    (ii) Measured maximum test torque for constant-speed engines
according to Sec.  1065.610.
    (iii) Measured ``A'', ``B'', and ``C'' speeds for variable-speed
engines according to Sec.  1065.610.
    (iv) Measured intermediate speed for variable-speed engines
according to Sec.  1065.610.
    (v) For variable-speed engines with a low-speed governor, measure
warm idle speed according to Sec.  1065.510(b) and use this speed for
cycle generation in Sec.  1065.512. For engines with no low-speed
governor, instead use the manufacturer-declared warm idle speed.
    (2) Required declared speeds. You must declare the lowest engine
speed possible with minimum load (i.e., manufacturer-declared warm idle
speed). This is applicable only to variable-speed engines with no low-
speed governor. For engines with no low-speed governor, the declared
warm idle speed is used for cycle generation in Sec.  1065.512. Declare
this speed in a way that is representative of in-use operation. For
example, if your engine is typically connected to an automatic
transmission or a hydrostatic transmission, declare this speed at the
idle speed at which your engine operates when the transmission is engaged.
    (3) Optional declared speeds. You may use declared speeds instead
of measured speeds as follows:
    (i) You may use a declared value for maximum test speed for
variable-speed engines if it is within (97.5 to 102.5)% of the
corresponding measured value. You may use a higher declared speed if
the length of the ``vector'' at the declared speed is within 2.0% of
the length of the ``vector'' at the measured value. The term vector
refers to the square root of the sum of normalized engine speed squared
and the normalized full-load power (at that speed) squared, consistent
with the calculations in Sec.  1065.610.
    (ii) You may use a declared value for intermediate, ``A'', ``B'',
or ``C'' speeds for steady-state tests if the declared value is within
(97.5 to 102.5)% of the corresponding measured value.
    (4) Required declared torques. If a nonzero idle or minimum torque
is representative of in-use operation, you must declare the appropriate
torque as follows:
    (i) For variable-speed engines, declare a warm idle torque that is
representative of in-use operation. For example, if your engine is
typically connected to an automatic transmission or a hydrostatic
transmission, declare the torque that occurs at the idle speed at which
your engine operates when the transmission is engaged. Use this value
for cycle generation. You may use multiple warm idle torques and
associated idle speeds in cycle generation for representative testing.
For example, for cycles that start the engine and begin with idle, you
may start a cycle in idle with the transmission in neutral with zero
torque and later switch to a different idle with the transmission in
drive with the Curb-Idle Transmission Torque (CITT). For variable-speed
engines intended primarily for propulsion of a vehicle with an
automatic transmission where that engine is subject to a transient duty
cycle with idle operation, you must declare a CITT. You must specify a
CITT based on typical applications at the mean of the range of idle
speeds you specify at stabilized temperature conditions.
    (ii) For constant-speed engines, declare a warm minimum torque that
is representative of in-use operation. For example, if your engine is
typically connected to a machine that does not operate below a certain
minimum torque, declare this torque and use it for cycle generation.
    (5) Optional declared torques. For constant-speed engines you may
declare a maximum test torque. You may use the declared value for cycle
generation if it is within (95 to 100)% of the measured value.
    (g) Other mapping procedures. You may use other mapping procedures
if you believe the procedures specified in this section are unsafe or
unrepresentative for your engine. Any alternate techniques you use must
satisfy the intent of the specified mapping procedures, which is to
determine the maximum available torque at all engine speeds that occur
during a duty cycle. Identify any deviations from this section's
mapping procedures when you submit data to us.

• 99. Section 1065.512 is revised to read as follows:

Sec.  1065.512  Duty cycle generation.

    (a) Generate duty cycles according to this section if the standard-
setting part requires engine mapping to generate a duty cycle for your
engine configuration. The standard-setting part generally defines
applicable duty cycles in a normalized format. A normalized duty cycle
consists of a sequence of paired values for speed and torque or for
speed and power.
    (b) Transform normalized values of speed, torque, and power using
the following conventions:
    (1) Engine speed for variable-speed engines. For variable-speed
engines, normalized speed may be expressed as a percentage between warm
idle speed, f_nidle, and maximum test speed,
f_ntest, or speed may be expressed by referring to a defined
speed by name, such as ``warm idle,'' ``intermediate speed,'' or ``A,''
``B,'' or ``C'' speed. Section 1065.610 describes how to transform
these normalized values into a sequence of reference speeds,
f_nref. Running duty cycles with negative or small normalized
speed values near warm idle speed may cause low-speed idle governors to
activate and the engine torque to exceed the reference torque even
though the operator demand is at a minimum. In such cases, we recommend
controlling the dynamometer so it gives priority to follow the
reference torque instead of the reference speed and let the engine
govern the speed. Note that the cycle-validation criteria in Sec. 
1065.514 allow an engine to govern itself. This allowance permits you
to test engines with enhanced-idle devices and to simulate the effects
of transmissions such as automatic transmissions. For example, an
enhanced-idle device might be an idle speed value that is normally
commanded only under cold-start conditions to quickly warm up the
engine and aftertreatment devices. In this case, negative and very low
normalized speeds will generate reference speeds below this higher
enhanced idle speed and we recommend controlling the dynamometer so it
gives priority to follow the reference torque, controlling the operator
demand so it gives priority to follow reference speed and let the
engine govern the speed when the operator demand is at minimum.
    (2) Engine torque for variable-speed engines. For variable-speed
engines, normalized torque is expressed as a percentage of the mapped
torque at the corresponding reference speed. Section 1065.610 describes
how to transform normalized torques into a sequence of reference
torques, T_ref. Section 1065.610 also describes special
requirements for modifying transient duty cycles for variable-speed
engines intended primarily for propulsion of a vehicle with an
automatic transmission. Section 1065.610 also describes under what
conditions you may command T_ref greater than the reference
torque you calculated from a normalized duty cycle. This provision
permits you to

[[Page 25320]]

command T_ref values that are limited by a declared minimum
torque. For any negative torque commands, command minimum operator
demand and use the dynamometer to control engine speed to the reference
speed, but if reference speed is so low that the idle governor
activates, we recommend using the dynamometer to control torque to
zero, CITT, or a declared minimum torque as appropriate. Note that you
may omit power and torque points during motoring from the cycle-
validation criteria in Sec.  1065.514. Also, use the maximum mapped
torque at the minimum mapped speed as the maximum torque for any
reference speed at or below the minimum mapped speed.
    (3) Engine torque for constant-speed engines. For constant-speed
engines, normalized torque is expressed as a percentage of maximum test
torque, T_test. Section 1065.610 describes how to transform
normalized torques into a sequence of reference torques,
T_ref. Section 1065.610 also describes under what conditions
you may command T_ref greater than the reference torque you
calculated from the normalized duty cycle. This provision permits you to
command T_ref values that are limited by a declared minimum torque.
    (4) Engine power. For all engines, normalized power is expressed as
a percentage of mapped power at maximum test speed, f_ntest,
unless otherwise specified by the standard-setting part. Section
1065.610 describes how to transform these normalized values into a
sequence of reference powers, P_ref. Convert these reference
powers to corresponding torques for operator demand and dynamometer
control. Use the reference speed associated with each reference power
point for this conversion. As with cycles specified with % torque,
issue torque commands more frequently and linearly interpolate between
these reference torque values generated from cycles with % power.
    (5) Ramped-modal cycles. For ramped modal cycles, generate
reference speed and torque values at 1 Hz and use this sequence of
points to run the cycle and validate it in the same manner as with a
transient cycle. During the transition between modes, linearly ramp the
denormalized reference speed and torque values between modes to
generate reference points at 1 Hz. Do not linearly ramp the normalized
reference torque values between modes and then denormalize them. Do not
linearly ramp normalized or denormalized reference power points. These
cases will produce nonlinear torque ramps in the denormalized reference
torques. If the speed and torque ramp runs through a point above the
engine's torque curve, continue to command the reference torques and
allow the operator demand to go to maximum. Note that you may omit
power and either torque or speed points from the cycle-validation
criteria under these conditions as specified in Sec.  1065.514.
    (c) For variable-speed engines, command reference speeds and
torques sequentially to perform a duty cycle. Issue speed and torque
commands at a frequency of at least 5 Hz for transient cycles and at
least 1 Hz for steady-state cycles (i.e., discrete-mode and ramped-
modal). Linearly interpolate between the 1 Hz reference values
specified in the standard-setting part to determine more frequently
issued reference speeds and torques. During an emission test, record
the feedback speeds and torques at a frequency of at least 5 Hz for
transient cycles and at least 1 Hz for steady-state cycles. For
transient cycles, you may record the feedback speeds and torques at
lower frequencies (as low as 1 Hz) if you record the average value over
the time interval between recorded values. Calculate the average values
based on feedback values updated at a frequency of at least 5 Hz. Use
these recorded values to calculate cycle-validation statistics and
total work.
    (d) For constant-speed engines, operate the engine with the same
production governor you used to map the engine in Sec.  1065.510 or
simulate the in-use operation of a governor the same way you simulated
it to map the engine in Sec.  1065.510. Command reference torque values
sequentially to perform a duty cycle. Issue torque commands at a
frequency of at least 5 Hz for transient cycles and at least 1 Hz for
steady-state cycles (i.e., discrete-mode, ramped-modal). Linearly
interpolate between the 1 Hz reference values specified in the
standard-setting part to determine more frequently issued reference
torque values. During an emission test, record the feedback speeds and
torques at a frequency of at least 5 Hz for transient cycles and at
least 1 Hz for steady-state cycles. For transient cycles, you may
record the feedback speeds and torques at lower frequencies (as low as
1 Hz) if you record the average value over the time interval between
recorded values. Calculate the average values based on feedback values
updated at a frequency of at least 5 Hz. Use these recorded values to
calculate cycle-validation statistics and total work.
    (e) You may perform practice duty cycles with the test engine to
optimize operator demand and dynamometer controls to meet the cycle-
validation criteria specified in Sec.  1065.514.

• 100. Section 1065.514 is revised to read as follows:

Sec.  1065.514  Cycle-validation criteria for operation over specified
duty cycles.

    Validate the execution of your duty cycle according to this section
unless the standard-setting part specifies otherwise. This section
describes how to determine if the engine's operation during the test
adequately matched the reference duty cycle. This section applies only
to speed, torque, and power from the engine's primary output shaft.
Other work inputs and outputs are not subject to cycle-validation
criteria. You must compare the original reference duty cycle points
generated as described in Sec.  1065.512 to the corresponding feedback
values recorded during the test. You may compare reference duty cycle
points recorded during the test to the corresponding feedback values
recorded during the test as long as the recorded reference values match
the original points generated in Sec.  1065.512. The number of points
in the validation regression are based on the number of points in the
original reference duty cycle generated in Sec.  1065.512. For example
if the original cycle has 1199 reference points at 1 Hz, then the
regression will have up to 1199 pairs of reference and feedback values
at the corresponding moments in the test. The feedback speed and torque
signals may be filtered--either in real-time while the test is run or
afterward in the analysis program. Any filtering that is used on the
feedback signals used for cycle validation must also be used for
calculating work. Feedback signals for control loops may use different
filtering.
    (a) Testing performed by EPA. Our tests must meet the
specifications of paragraph (f) of this section, unless we determine
that failing to meet the specifications is related to engine
performance rather than to shortcomings of the dynamometer or other
laboratory equipment.
    (b) Testing performed by manufacturers. Emission tests that meet
the specifications of paragraph (f) of this section satisfy the
standard-setting part's requirements for duty cycles. You may ask to
use a dynamometer or other laboratory equipment that cannot meet those
specifications. We will approve your request as long as using the
alternate equipment does not adversely affect your ability to show
compliance with the applicable emission standards.
    (c) Time-alignment. Because time lag between feedback values and
the reference values may bias cycle-validation results, you may advance
or delay the entire sequence of feedback engine speed and torque pairs to

[[Page 25321]]

synchronize them with the reference sequence. If you advance or delay
feedback signals for cycle validation, you must make the same
adjustment for calculating work. You may use linear interpolation
between successive recorded feedback signals to time shift an amount
that is a fraction of the recording period.
    (d) Omitting additional points. Besides engine cranking, you may
omit additional points from cycle-validation statistics as described in
the following table:

   Table 1 of Sec.   1065.514.--Permissible Criteria for Omitting Points From Duty-Cycle Regression Statistics
----------------------------------------------------------------------------------------------------------------
  When operator demand is at its . . .         you may omit . . .                       if . . .
----------------------------------------------------------------------------------------------------------------
For reference duty cycles that are specified in terms of speed and torque (fnref, Tref):
----------------------------------------------------------------------------------------------------------------
minimum.................................  power and torque...........  Tref < 0% (motoring).
minimum.................................  power and speed............  fnref = 0% (idle speed) and Tref = 0%
                                                                        (idle torque) and Tref-(2% [middot] Tmax
                                                                        mapped) < T < Tref + (2% [middot]  fnref or T < Tref but not if fn >
                                           speed.                       (fnref [middot] 102%) and T >Tref + (2%
                                                                        [middot] < fnref or T < Tref but not if
                                           speed.                       [fnof]n < ([fnof]nref [middot] 98%) and
                                                                        T < Tref-(2% [middot] Tmax mapped).
----------------------------------------------------------------------------------------------------------------
For reference duty cycles that are specified in terms of speed and power (fnref, Pref):
----------------------------------------------------------------------------------------------------------------
minimum.................................  power and torque...........  < Pref < 0% (motoring).
minimum.................................  power and speed............  [fnof]nref = 0% (idle speed) and Pref =
                                                                        0% (idle power) and Pref-(2% [middot]
                                                                        Pmax mapped) < Pref + (2% [middot]
                                                                        Pmax mapped).
minimum.................................  power and either torque or   fn >[fnof]nref or < P > Pref but not if
                                           speed.                       fn > (fnref [middot] 102%) and P < Pref
                                                                        + (2% [middot] Pmax mapped).
maximum.................................  power and either torque or   fn < fnref or P < Pref but not if [fnof]n
                                           speed.                       (fnref [middot] 98%) and P < Pref-(2%
                                                                        [middot] Pmax mapped).
----------------------------------------------------------------------------------------------------------------

    (e) Statistical parameters. Use the remaining points to calculate
regression statistics described in Sec.  1065.602. Round calculated
regression statistics to the same number of significant digits as the
criteria to which they are compared. Refer to Table 2 of Sec.  1065.514
for the default criteria and refer to the standard-setting part to
determine if there are other criteria for your engine. Calculate the
following regression statistics:
    (1) Slopes for feedback speed, a_1fn, feedback torque,
a_1T, and feedback power a_1P.
    (2) Intercepts for feedback speed, a_0fn, feedback
torque, a_0T, and feedback power a_0P.
    (3) Standard estimates of error for feedback speed, SEE_fn,
feedback torque, SEE_T, and feedback power SEE_P.
    (4) Coefficients of determination for feedback speed,
r\2\_fn, feedback torque, r\2\_T, and feedback
power r\2\_P.
    (f) Cycle-validation criteria. Unless the standard-setting part
specifies otherwise, use the following criteria to validate a duty cycle:
    (1) For variable-speed engines, apply all the statistical criteria
in Table 2 of this section.
    (2) For constant-speed engines, apply only the statistical criteria
for torque in Table 2 of this section.
    (3) For discrete-mode steady-state testing, apply cycle-validation
criteria using one of the following approaches:
    (i) Treat the sampling periods from the series of test modes as a
continuous sampling period, analogous to ramped-modal testing and apply
statistical criteria as described in paragraph (f)(1) or (2) of this
section.
    (ii) Evaluate each mode separately to validate the duty cycle. For
variable-speed engines, all speed values measured during the sampling
period for each mode would need to stay within a tolerance of 2 percent
of the reference value, and all load values would need to stay within a
tolerance of 2 percent or &plusmn; 0.27 N[middot]m of the reference
value, whichever is greater. Also, the mean speed value during the
sampling period for each mode would need to be within 1 percent of the
reference value, and the mean load value would need to stay within 1
percent or &plusmn; 0.12 N[middot]m of the reference value,
whichever is greater. The same torque criteria apply for constant-speed
engines but the speed criteria do not apply.

              Table 2 of Sec.   1065.514.--Default Statistical Criteria for Validating Duty Cycles
----------------------------------------------------------------------------------------------------------------
              Parameter                         Speed                    Torque                   Power
----------------------------------------------------------------------------------------------------------------
Slope, a1............................  0.950 <= a1 <= 1.030...  0.830 <= a1 <= 1.030...  0.830 <= a1 <= 1.030.
Absolute value of intercept,           <= 10% of warm idle....  <= 2.0% of maximum       <= 2.0% of maximum
 [verbarlm]a0[verbarlm].                                         mapped torque.           mapped power.
Standard error of estimate, SEE......  <= 5.0% of maximum test  <= 10% of maximum        <= 10% of maximum
                                        speed.                   mapped torque.           mapped power.
Coefficient of determination,r \2\...  >= 0.970...............  >= 0.850...............  >= 0.910.
----------------------------------------------------------------------------------------------------------------

• 101. Section 1065.520 is revised to read as follows:

Sec.  1065.520  Pre-test verification procedures and pre-test data collection.

    (a) If your engine must comply with a PM standard, follow the
procedures for PM sample preconditioning and tare weighing according to
Sec.  1065.590.
    (b) Unless the standard-setting part specifies different
tolerances, verify that

[[Page 25322]]

ambient conditions are within the following tolerances before the test:
    (1) Ambient temperature of (20 to 30) [deg]C.
    (2) Atmospheric pressure of (80.000 to 103.325) kPa and within
&plusmn; 5 kPa of the value recorded at the time of the last engine map.
    (3) Dilution air conditions as specified in Sec.  1065.140, except
in cases where you preheat your CVS before a cold start test.
    (c) You may test engines at any intake-air humidity, and we may
test engines at any intake-air humidity.
    (d) Verify that auxiliary-work inputs and outputs are configured as
they were during engine mapping, as described inSec.  1065.510(a).
    (e) You may perform a final calibration of the speed, torque, and
proportional-flow control systems, which may include performing
practice duty cycles.
    (f) You may perform the following recommended procedure to
precondition sampling systems:
    (1) Start the engine and use good engineering judgment to bring it
to one of the following:
    (i) 100% torque at any speed above its peak-torque speed.
    (ii) 100% operator demand.
    (2) Operate any dilution systems at their expected flow rates.
Prevent aqueous condensation in the dilution systems.
    (3) Operate any PM sampling systems at their expected flow rates.
    (4) Sample PM for at least 10 min using any sample media. You may
change sample media during preconditioning. You may discard
preconditioning samples without weighing them.
    (5) You may purge any gaseous sampling systems during
preconditioning.
    (6) You may conduct calibrations or verifications on any idle
equipment or analyzers during preconditioning.
    (7) Proceed with the test sequence described in Sec. 
1065.530(a)(1).
    (g) Verify the amount of nonmethane contamination in the exhaust
and background HC sampling systems within eight hours of starting each
duty-cycle sequence for laboratory tests. You may verify the
contamination of a background HC sampling system by reading the last
bag fill and purge using zero gas. For any NMHC measurement system that
involves separately measuring methane and subtracting it from a THC
measurement, verify the amount of THC contamination using only the THC
analyzer response. There is no need to operate any separate methane
analyzer for this verification, however you may measure and correct for
THC contamination in the CH₄ sample train for the cases
where NMHC is determined by subtracting CH₄ from THC, using
an NMC as configured in Sec.  1065.365(d), (e), and (f); and the
calculations in Sec.  1065.660(b)(2). Perform this verification as follows:
    (1) Select the HC analyzer range for measuring the flow-weighted
mean concentration expected at the HC standard.
    (2) Zero the HC analyzer at the analyzer zero or sample port. Note
that FID zero and span balance gases may be any combination of purified
air or purified nitrogen that meets the specifications of Sec. 
1065.750. We recommend FID analyzer zero and span gases that contain
approximately the flow-weighted mean concentration of O2 expected
during testing.
    (3) Span the HC analyzer using span gas introduced at the analyzer
span or sample port. Span on a carbon number basis of one
(C₁). For example, if you use a C₃H₈
span gas of concentration 200 &mu;mol/mol, span the FID to respond with
a value of 600 &mu;mol/mol.
    (4) Overflow zero gas at the HC probe or into a fitting between the
HC probe and its transfer line.
    (5) Measure the THC concentration in the sampling and background
systems as follows:
    (i) For continuous sampling, record the mean THC concentration as
overflow zero air flows.
    (ii) For batch sampling, fill the sample medium (e.g., filter) and
record its mean THC concentration.
    (iii) For the background system, record the mean THC concentration
of the last fill and purge.
    (6) Record this value as the initial THC concentration,
_{xTHC[THC-FID]init-} and use it to correct measured values as
described in Sec.  1065.660.
    (7) If any of the _{xTHC[THC-FID]init-} values exceed the
greatest of the following values, determine the source of the
contamination and take corrective action, such as purging the system
during an additional preconditioning cycle or replacing contaminated
portions:
    (i) 2% of the flow-weighted mean wet, net concentration expected at
the HC (THC or NMHC) standard.
    (ii) 2% of the flow-weighted mean wet, net concentration of HC (THC
or NMHC) measured during testing.
    (iii) 2 &mu;mol/mol.
    (8) If corrective action does not resolve the deficiency, you may
request to use the contaminated system as an alternate procedure under
Sec.  1065.10.

• 102. Section 1065.525 is revised to read as follows:

Sec.  1065.525  Engine starting, restarting, shutdown, and optional
repeating of void discrete modes.

    (a) Start the engine using one of the following methods:
    (1) Start the engine as recommended in the owners manual using a
production starter motor or air-start system and either an adequately
charged battery, a suitable power supply, or a suitable compressed air
source.
    (2) Use the dynamometer to start the engine. To do this, motor the
engine within &plusmn;25% of its typical in-use cranking speed.
Stop cranking within 1 second of starting the engine.
    (b) If the engine does not start after 15 seconds of cranking, stop
cranking and determine why the engine failed to start, unless the
owners manual or the service-repair manual describes the longer
cranking time as normal.
    (c) Respond to engine stalling with the following steps:
    (1) If the engine stalls during warm-up before emission sampling
begins, restart the engine and continue warm-up.
    (2) If the engine stalls during preconditioning before emission
sampling begins, restart the engine and restart the preconditioning
sequence.
    (3) If the engine stalls at any time after emission sampling begins
for a transient test or ramped-modal cycle test, the test is void.
    (4) Except as described in paragraph (d) of this section, void the
test if the engine stalls at any time after emission sampling begins.
    (d) If emission sampling is interrupted during one of the modes of
a discrete-mode test, you may void the results only for that individual
mode and perform the following steps to continue the test:
    (1) If the engine has stalled, restart the engine.
    (2) Use good engineering judgment to restart the test sequence
using the appropriate steps in Sec.  1065.530(b).
    (3) Precondition the engine by operating at the previous mode for
approximately the same amount of time it operated at that mode for the
last emission measurement.
    (4) Advance to the mode at which the engine stalled and continue
with the duty cycle as specified in the standard-setting part.
    (5) Complete the remainder of the test according to the
requirements in this subpart.
    (e) Shut down the engine according to the manufacturer's
specifications.

• 103. Section 1065.530 is revised to read as follows:

Sec.  1065.530  Emission test sequence.

    (a) Time the start of testing as follows:

[[Page 25323]]

    (1) Perform one of the following if you precondition sampling
systems as described in Sec.  1065.520(f):
    (i) For cold-start duty cycles, shut down the engine. Unless the
standard-setting part specifies that you may only perform a natural
engine cooldown, you may perform a forced engine cooldown. Use good
engineering judgment to set up systems to send cooling air across the
engine, to send cool oil through the engine lubrication system, to
remove heat from coolant through the engine cooling system, and to
remove heat from any exhaust aftertreatment systems. In the case of a
forced aftertreatment cooldown, good engineering judgment would
indicate that you not start flowing cooling air until the
aftertreatment system has cooled below its catalytic activation
temperature. For platinum-group metal catalysts, this temperature is
about 200 [deg]C. Once the aftertreatment system has naturally cooled
below its catalytic activation temperature, good engineering judgment
would indicate that you use clean air with a temperature of at least 15
[deg]C, and direct the air through the aftertreatment system in the
normal direction of exhaust flow. Do not use any cooling procedure that
results in unrepresentative emissions (see Sec.  1065.10(c)(1)). You
may start a cold-start duty cycle when the temperatures of an engine's
lubricant, coolant, and aftertreatment systems are all between (20 and
30) [deg]C.
    (ii) For hot-start emission measurements, shut down the engine.
Start the hot-start duty cycle as specified in the standard-setting part.
    (iii) For testing that involves hot-stabilized emission
measurements, such as any steady-state testing, you may continue to
operate the engine at maximum test speed and 100% torque if that is the
first operating point. Otherwise, operate the engine at warm idle or the
first operating point of the duty cycle. In any case, start the emission
test within 10 min after you complete the preconditioning procedure.
    (2) If you do not precondition sampling systems, perform one of the
following:
    (i) For cold-start duty cycles, prepare the engine according to
paragraph (a)(1)(i) of this section.
    (ii) For hot-start emission measurements, first operate the engine
at any speed above peak-torque speed and at (65 to 85)% of maximum
mapped power until either the engine coolant, block, or head absolute
temperature is within &plusmn;2% of its mean value for at least 2
min or until the engine thermostat controls engine temperature. Shut
down the engine. Start the duty cycle within 20 min of engine shutdown.
    (iii) For testing that involves hot-stabilized emission
measurements, bring the engine either to warm idle or the first
operating point of the duty cycle. Start the test within 10 min of
achieving temperature stability. Determine temperature stability either
as the point at which the engine coolant, block, or head absolute
temperature is within &plusmn;2% of its mean value for at least 2
min, or as the point at which the engine thermostat controls engine
temperature.
    (b) Take the following steps before emission sampling begins:
    (1) For batch sampling, connect clean storage media, such as
evacuated bags or tare-weighed filters.
    (2) Start all measurement instruments according to the instrument
manufacturer's instructions and using good engineering judgment.
    (3) Start dilution systems, sample pumps, cooling fans, and the
data-collection system.
    (4) Pre-heat or pre-cool heat exchangers in the sampling system to
within their operating temperature tolerances for a test.
    (5) Allow heated or cooled components such as sample lines,
filters, chillers, and pumps to stabilize at their operating
temperatures.
    (6) Verify that there are no significant vacuum-side leaks
according to Sec.  1065.345.
    (7) Adjust the sample flow rates to desired levels, using bypass
flow, if desired.
    (8) Zero or re-zero any electronic integrating devices, before the
start of any test interval.
    (9) Select gas analyzer ranges. You may automatically or manually
switch gas analyzer ranges during a test only if switching is performed
by changing the span over which the digital resolution of the
instrument is applied. During a test you may not switch the gains of an
analyzer's analog operational amplifier(s).
    (10) Zero and span all continuous analyzers using NIST-traceable
gases that meet the specifications of Sec.  1065.750. Span FID
analyzers on a carbon number basis of one (1), C₁. For
example, if you use a C₃H₈ span gas of
concentration 200 &mu;mol/mol, span the FID to respond with a value of
600 &mu;mol/mol. Span FID analyzers consistent with the determination
of their respective response factors, RF, and penetration fractions,
PF, according to Sec.  1065.365.
    (11) We recommend that you verify gas analyzer responses after
zeroing and spanning by sampling a calibration gas that has a
concentration near one-half of the span gas concentration. Based on the
results and good engineering judgment, you may decide whether or not to
re-zero, re-span, or re-calibrate a gas analyzer before starting a test.
    (12) If you correct for dilution air background concentrations of
engine exhaust constituents, start measuring and recording background
concentrations.
    (13) Drain any condensate from the intake air system and close any
intake air condensate drains that are not normally open during in-use
operation.
    (c) Start testing as follows:
    (1) If an engine is already running and warmed up, and starting is
not part of the duty cycle, perform the following for the various duty
cycles:
    (i) Transient and steady-state ramped-modal cycles. Simultaneously
start running the duty cycle, sampling exhaust gases, recording data,
and integrating measured values.
    (ii) Steady-state discrete-mode cycles. Control the engine
operation to match the first mode in the test cycle. This will require
controlling engine speed and load, engine load, or other operator
demand settings, as specified in the standard-setting part. Follow the
instructions in the standard-setting part to determine how long to
stabilize engine operation at each mode, how long to sample emissions
at each mode, and how to transition between modes.
    (2) If engine starting is part of the duty cycle, initiate data
logging, sampling of exhaust gases, and integrating measured values
before attempting to start the engine. Initiate the duty cycle when the
engine starts.
    (d) At the end of each test interval, continue to operate all
sampling and dilution systems to allow the sampling system's response
time to elapse. Then stop all sampling and recording, including the
recording of background samples. Finally, stop any integrating devices
and indicate the end of the duty cycle in the recorded data.
    (e) Shut down the engine if you have completed testing or if it is
part of the duty cycle.
    (f) If testing involves another duty cycle after a soak period with
the engine off, start a timer when the engine shuts down, and repeat
the steps in paragraphs (b) through (e) of this section as needed.
    (g) Take the following steps after emission sampling is complete:
    (1) For any proportional batch sample, such as a bag sample or PM
sample, verify that proportional sampling was maintained according to
Sec.  1065.545. Void any samples that did not maintain proportional
sampling according to Sec.  1065.545.

[[Page 25324]]

    (2) Place any used PM samples into covered or sealed containers and
return them to the PM-stabilization environment. Follow the PM sample
post-conditioning and total weighing procedures in Sec.  1065.595.
    (3) As soon as practical after the duty cycle is complete, or
during the soak period if practical, perform the following:
    (i) Zero and span all batch gas analyzers no later than 30 minutes
after the duty cycle is complete, or during the soak period if practical.
    (ii) Analyze any conventional gaseous batch samples no later than
30 minutes after the duty cycle is complete, or during the soak period
if practical.
    (iii) Analyze background samples no later than 60 minutes after the
duty cycle is complete.
    (iv) Analyze non-conventional gaseous batch samples, such as
ethanol (NMCHE) as soon as practical using good engineering judgment.
    (4) After quantifying exhaust gases, verify drift as follows:
    (i) For batch and continuous gas anlyzers, record the mean analyzer
value after stabilizing a zero gas to the analyzer. Stabilization may
include time to purge the analyzer of any sample gas, plus any
additional time to account for analyzer response.
    (ii) Record the mean analyzer value after stabilizing the span gas
to the analyzer. Stabilization may include time to purge the analyzer
of any sample gas, plus any additional time to account for analyzer
response.
    (iii) Use these data to validate and correct for drift as described
in Sec.  1065.550.
    (h) Unless the standard-setting part specifies otherwise, determine
whether or not the test meets the cycle-validation criteria in Sec. 
1065.514.
    (1) If the criteria void the test, you may retest using the same
denormalized duty cycle, or you may re-map the engine, denormalize the
reference duty cycle based on the new map and retest the engine using
the new denormalized duty cycle.
    (2) If the criteria void the test for a constant-speed engine only
during commands of maximum test torque, you may do the following:
    (i) Determine the first and last feedback speeds at which maximum
test torque was commanded.
    (ii) If the last speed is greater than or equal to 90% of the first
speed, the test is void. You may retest using the same denormalized
duty cycle, or you may re-map the engine, denormalize the reference
duty cycle based on the new map and retest the engine using the new
denormalized duty cycle.
    (iii) If the last speed is less than 90% of the first speed, reduce
maximum test torque by 5%, and proceed as follows:
    (A) Denormalize the entire duty cycle based on the reduced maximum
test torque according to Sec.  1065.512.
    (B) Retest the engine using the denormalized test cycle that is
based on the reduced maximum test torque.
    (C) If your engine still fails the cycle criteria, reduce the
maximum test torque by another 5% of the original maximum test torque.
    (D) If your engine fails after repeating this procedure four times,
such that your engine still fails after you have reduced the maximum
test torque by 20% of the original maximum test torque, notify us and
we will consider specifying a more appropriate duty cycle for your
engine under the provisions of Sec.  1065.10(c).
    (i) [Reserved]
    (j) Measure and record ambient temperature, pressure, and humidity,
as appropriate.

• 104. Section 1065.545 is revised to read as follows:

Sec.  1065.545  Validation of proportional flow control for batch
sampling and minimum dilution ratio for PM batch sampling.

    For any proportional batch sample such as a bag or PM filter,
demonstrate that proportional sampling was maintained using one of the
following, noting that you may omit up to 5% of the total number of
data points as outliers:
    (a) For any pair of flow meters, use recorded sample and total flow
rates, where total flow rate means the raw exhaust flow rate for raw
exhaust sampling and the dilute exhaust flow rate for CVS sampling, or
their 1 Hz means with the statistical calculations in Sec.  1065.602.
Determine the standard error of the estimate, SEE, of the sample flow
rate versus the total flow rate. For each test interval, demonstrate
that SEE was less than or equal to 3.5% of the mean sample flow rate.
    (b) For any pair of flow meters, use recorded sample and total flow
rates, where total flow rate means the raw exhaust flow rate for raw
exhaust sampling and the dilute exhaust flow rate for CVS sampling, or
their 1 Hz means to demonstrate that each flow rate was constant within
&plusmn;2.5% of its respective mean or target flow rate. You may
use the following options instead of recording the respective flow rate
of each type of meter:
    (1) Critical-flow venturi option. For critical-flow venturis, you
may use recorded venturi-inlet conditions or their 1 Hz means.
Demonstrate that the flow density at the venturi inlet was constant
within &plusmn;2.5% of the mean or target density over each test
interval. For a CVS critical-flow venturi, you may demonstrate this by
showing that the absolute temperature at the venturi inlet was constant
within &plusmn;4% of the mean or target absolute temperature over
each test interval.
    (2) Positive-displacement pump option. You may use recorded pump-
inlet conditions or their 1 Hz means. Demonstrate that the flow density
at the pump inlet was constant within &plusmn;2.5% of the mean or
target density over each test interval. For a CVS pump, you may
demonstrate this by showing that the absolute temperature at the pump
inlet was constant within &plusmn;2% of the mean or target absolute
temperature over each test interval.
    (c) Using good engineering judgment, demonstrate with an
engineering analysis that the proportional-flow control system
inherently ensures proportional sampling under all circumstances
expected during testing. For example, you might use CFVs for both
sample flow and total flow and demonstrate that they always have the
same inlet pressures and temperatures and that they always operate
under critical-flow conditions.
    (d) Use measured or calculated flows and/or tracer gas
concentrations (e.g., CO2) to determine the minimum dilution ratio for
PM batch sampling over the test interval.

• 105. Section 1065.550 is revised to read as follows:

Sec.  1065.550  Gas analyzer range validation, drift validation, and
drift correction.

    (a) Range validation. If an analyzer operated above 100% of its
range at any time during the test, perform the following steps:
    (1) For batch sampling, re-analyze the sample using the lowest
analyzer range that results in a maximum instrument response below
100%. Report the result from the lowest range from which the analyzer
operates below 100% of its range.
    (2) For continuous sampling, repeat the entire test using the next
higher analyzer range. If the analyzer again operates above 100% of its
range, repeat the test using the next higher range. Continue to repeat
the test until the analyzer always operates at less than 100% of its range.
    (b) Drift validation and drift correction. Calculate two sets of
brake-specific emission results. Calculate one set using the data
before drift correction and calculate the other set after correcting
all the data for drift according to Sec.  1065.672. Use the two sets of
brake-specific emission results as follows:

[[Page 25325]]

    (1) This test is validated for drift if, for each regulated
pollutant, the difference between the uncorrected and the corrected
brake-specific emission values is within &plusmn;4% of the
uncorrected results or applicable standard, whichever is greater. If
not, the entire test is void.
    (2) If the test is validated for drift, you must use only the
drift-corrected emission results when reporting emissions, unless you
demonstrate to us that using the drift-corrected results adversely
affects your ability to demonstrate that your engine complies with the
applicable standards.

• 106. Section 1065.590 is revised to read as follows:

Sec.  1065.590  PM sampling media (e.g., filters) preconditioning and
tare weighing.

    Before an emission test, take the following steps to prepare PM
sampling media (e.g., filters) and equipment for PM measurements:
    (a) Make sure the balance and PM-stabilization environments meet
the periodic verifications in Sec.  1065.390.
    (b) Visually inspect unused sample media (e.g., filters) for
defects and discard defective media.
    (c) To handle PM sampling media (e.g., filters), use electrically
grounded tweezers or a grounding strap, as described in Sec.  1065.190.
    (d) Place unused sample media (e.g., filters) in one or more
containers that are open to the PM-stabilization environment. If you
are using filters, you may place them in the bottom half of a filter
cassette.
    (e) Stabilize sample media (e.g., filters) in the PM-stabilization
environment. Consider an unused sample medium stabilized as long as it
has been in the PM-stabilization environment for a minimum of 30 min,
during which the PM-stabilization environment has been within the
specifications of Sec.  1065.190.
    (f) Weigh the sample media (e.g., filters) automatically or
manually, as follows:
    (1) For automatic weighing, follow the automation system
manufacturer's instructions to prepare samples for weighing. This may
include placing the samples in a special container.
    (2) For manual weighing, use good engineering judgment to determine
if substitution weighing is necessary to show that an engine meets the
applicable standard. You may follow the substitution weighing procedure
in paragraph (j) of this section, or you may develop your own procedure.
    (g) Correct the measured mass of each sample medium (e.g., filter)
for buoyancy as described in Sec.  1065.690. These buoyancy-corrected
values are subsequently subtracted from the post-test mass of the
corresponding sample media (e.g., filters) and collected PM to
determine the mass of PM emitted during the test.
    (h) You may repeat measurements to determine the mean mass of each
sample medium (e.g., filter). Use good engineering judgment to exclude
outliers from the calculation of mean mass values.
    (i) If you use filters as sample media, load unused filters that
have been tare-weighed into clean filter cassettes and place the loaded
cassettes in a clean, covered or sealed container before removing them
from the stabilization environment for transport to the test site for
sampling. We recommend that you keep filter cassettes clean by
periodically washing or wiping them with a compatible solvent applied
using a lint-free cloth. Depending upon your cassette material, ethanol
(C2H5OH) might be an acceptable solvent. Your cleaning frequency will
depend on your engine's level of PM and HC emissions.
    (j) Substitution weighing involves measurement of a reference
weight before and after each weighing of PM sampling media (e.g.,
filters). While substitution weighing requires more measurements, it
corrects for a balance's zero-drift and it relies on balance linearity
only over a small range. This is most advantageous when quantifying net
PM masses that are less than 0.1% of the sample medium's mass. However,
it may not be advantageous when net PM masses exceed 1% of the sample
medium's mass. If you utilize substitution weighing, it must be used
for both pre-test and post-test weighing. The same substitution weight
must be used for both pre-test and post-test weighing. Correct the mass
of the substitution weight for buoyancy if the density of the
substitution weight is less than 2.0 g/cm3. The following
steps are an example of substitution weighing:
    (1) Use electrically grounded tweezers or a grounding strap, as
described in Sec.  1065.190.
    (2) Use a static neutralizer as described in Sec.  1065.190 to
minimize static electric charge on any object before it is placed on
the balance pan.
    (3) Select a substitution weight that meets the requirements for
calibration weights found in Sec.  1065.790. The substitution weight
must also have the same density as the weight you use to span the
microbalance, and be similar in mass to an unused sample medium (e.g.,
filter). A 47 mm PTFE membrane filter will typically have a mass in the
range of 80 to 100 mg.
    (4) Record the stable balance reading, then remove the calibration
weight.
    (5) Weigh an unused sample medium (e.g., a new filter), record the
stable balance reading and record the balance environment's dewpoint,
ambient temperature, and atmospheric pressure.
    (6) Reweigh the calibration weight and record the stable balance
reading.
    (7) Calculate the arithmetic mean of the two calibration-weight
readings that you recorded immediately before and after weighing the
unused sample. Subtract that mean value from the unused sample reading,
then add the true mass of the calibration weight as stated on the
calibration-weight certificate. Record this result. This is the unused
sample's tare weight without correcting for buoyancy.
    (8) Repeat these substitution-weighing steps for the remainder of
your unused sample media.
    (9) Once weighing is completed, follow the instructions given in
paragraphs (g) through (i) of this section.

• 107. Section 1065.595 is revised to read as follows:

Sec.  1065.595  PM sample post-conditioning and total weighing.

    After testing is complete, return the sample media (e.g., filters)
to the weighing and PM-stabilization environments.
    (a) Make sure the weighing and PM-stabilization environments meet
the ambient condition specifications in Sec.  1065.190(e)(1). If those
specifications are not met, leave the test sample media (e.g., filters)
covered until proper conditions have been met.
    (b) In the PM-stabilization environment, remove PM samples from
sealed containers. If you use filters, you may remove them from their
cassettes before or after stabilization. We recommend always removing
the top portion of the cassette before stabilization. When you remove a
filter from a cassette, separate the top half of the cassette from the
bottom half using a cassette separator designed for this purpose.
    (c) To handle PM samples, use electrically grounded tweezers or a
grounding strap, as described in Sec.  1065.190.
    (d) Visually inspect the sampling media (e.g., filters) and
collected particulate. If either the sample media (e.g., filters) or
particulate sample appear to have been compromised, or the particulate
matter contacts any surface other than the filter, the sample may not
be used to determine particulate emissions. In the case of contact with
another surface, clean the affected surface before continuing.
    (e) To stabilize PM samples, place them in one or more containers
that are

[[Page 25326]]

open to the PM-stabilization environment, as described in Sec. 
1065.190. If you expect that a sample medium's (e.g., filter's) total
surface concentration of PM will be less than 400 &mu;g, assuming a 38
mm diameter filter stain area, expose the filter to a PM-stabilization
environment meeting the specifications of Sec.  1065.190 for at least
30 minutes before weighing. If you expect a higher PM concentration or
do not know what PM concentration to expect, expose the filter to the
stabilization environment for at least 60 minutes before weighing. Note
that 400 &mu;g on sample media (e.g., filters) is an approximate net
mass of 0.07 g/kW[middot]hr for a hot-start test with compression-
ignition engines tested according to 40 CFR part 86, subpart N, or 50
mg/mile for light-duty vehicles tested according to 40 CFR part 86,
subpart B.
    (f) Repeat the procedures in Sec.  1065.590(f) through (i) to
determine post-test mass of the sample media (e.g., filters).
    (g) Subtract each buoyancy-corrected tare mass of the sample medium
(e.g., filter) from its respective buoyancy-corrected mass. The result
is the net PM mass, m_PM. Use m_PM in emission
calculations in Sec.  1065.650.

Subpart G--[Amended]

• 108. Section 1065.601 is amended by revising paragraph (c)(1) to read
as follows:

Sec.  1065.601  Overview.

* * * * *
    (c) * * *
    (1) Mass-based emission calculations prescribed by the
International Organization for Standardization (ISO), according to ISO
8178, except the following:
    (i) ISO 8178-1 Section 14.4, NO_X Correction for Humidity
and Temperature. See Sec.  1065.670 for approved methods for humidity
corrections.
    (ii) ISO 8178-1 Section 15.1, Particulate Correction Factor for
Humidity.
* * * * *
• 109. Section 1065.602 is amended by revising paragraphs (f)(3) before
the table and (l) introductory text to read as follows:

Sec.  1065.602  Statistics.

* * * * *
    (f) * * *
    (3) Use Table 1 of this section to compare t to the
t_crit values tabulated versus the number of degrees of
freedom. If t is less than t_crit, then t passes the t-test.
The Microsoft Excel software package contains a TINV function that
returns results equivalent to Sec.  1065.602 Table 1 and may be used in
place of Table 1.
* * * * *
    (l) Flow-weighted mean concentration. In some sections of this
part, you may need to calculate a flow-weighted mean concentration to
determine the applicability of certain provisions. A flow-weighted mean
is the mean of a quantity after it is weighted proportional to a
corresponding flow rate. For example, if a gas concentration is
measured continuously from the raw exhaust of an engine, its flow-
weighted mean concentration is the sum of the products of each recorded
concentration times its respective exhaust molar flow rate, divided by
the sum of the recorded flow rate values. As another example, the bag
concentration from a CVS system is the same as the flow-weighted mean
concentration because the CVS system itself flow-weights the bag
concentration. You might already expect a certain flow-weighted mean
concentration of an emission at its standard based on previous testing
with similar engines or testing with similar equipment and instruments.
If you need to estimate your expected flow-weighted mean concentration
of an emission at its standard, we recommend using the following
examples as a guide for how to estimate the flow-weighted mean
concentration expected at the standard. Note that these examples are
not exact and that they contain assumptions that are not always valid.
Use good engineering judgment to determine if you can use similar
assumptions.
* * * * *

• 110. Section 1065.610 is revised to read as follows:

Sec.  1065.610  Duty cycle generation.

    This section describes how to generate duty cycles that are
specific to your engine, based on the normalized duty cycles in the
standard-setting part. During an emission test, use a duty cycle that
is specific to your engine to command engine speed, torque, and power,
as applicable, using an engine dynamometer and an engine operator
demand. Paragraph (a) of this section describes how to ``normalize''
your engine's map to determine the maximum test speed and torque for
your engine. The rest of this section describes how to use these values
to ``denormalize'' the duty cycles in the standard-setting parts, which
are all published on a normalized basis. Thus, the term ``normalized''
in paragraph (a) of this section refers to different values than it
does in the rest of the section.
    (a) Maximum test speed, f_ntest. This section generally
applies to duty cycles for variable-speed engines. For constant-speed
engines subject to duty cycles that specify normalized speed commands,
use the no-load governed speed as the measured f_ntest. This
is the highest engine speed where an engine outputs zero torque. For
variable-speed engines, determine the measured f_ntest from
the power-versus-speed map, generated according to Sec.  1065.510, as
follows:
    (1) Based on the map, determine maximum power, Pmax, and
the speed at which maximum power occurred, f_nPmax. Divide
every recorded power by Pmax and divide every recorded speed
by f_nPmax. The result is a normalized power-versus-speed
map. Your measured f_ntest is the speed at which the sum of
the squares of normalized speed and power is maximum, as follows:

f_ntest = f_ni at the maximum of
(f_nnormi\2\ + P_normi\2\)

Eq. 1065.610-1

Where:

f_ntest = maximum test speed.
i = an indexing variable that represents one recorded value of an
engine map.
f_nnormi = an engine speed normalized by dividing it by
f_nPmax.
P_normi = an engine power normalized by dividing it by
Pmax.

Example:

(f_nnorm1 = 1.002, P_norm1 = 0.978,
f_n1 = 2359.71)
(f_nnorm2 = 1.004, P_norm2 = 0.977,
f_n2 = 2364.42)
(f_nnorm3 = 1.006, P_norm3 = 0.974,
f_n3 = 2369.13)
(f_nnorm1₂ + P_norm1\2\) = (1.002\2\
+ 0.978\2\) = 1.960
(f_nnorm2\2\ + P_norm2\2\) = (1.004\2\ +
0.977\2\) = 1.963
(f_nnorm3\2\ + P_norm3\2\) = (1.006\2\ +
0.974\2\) = 1.961
maximum = 1.963 at i = 2
f_ntest = 2364.42 rev/min

    (2) For variable-speed engines, transform normalized speeds to
reference speeds according to paragraph (c) of this section by using
the measured maximum test speed determined according to paragraph
(a)(1) of this section--or use your declared maximum test speed, as
allowed in Sec.  1065.510.
    (3) For constant-speed engines, transform normalized speeds to
reference speeds according to paragraph (c) of this section by using
the measured no-load governed speed--or use your declared maximum test
speed, as allowed in Sec.  1065.510.
    (b) Maximum test torque, Ttest. For constant-speed engines,
determine the measured T_test from the power-versus-speed
map, generated according to Sec.  1065.510, as follows:
    (1) Based on the map, determine maximum power, P_max, and
the speed at which maximum power occurs, f_nPmax. Divide
every recorded power by P_max and divide every recorded speed
by f_nPmax. The result is a normalized power-

[[Page 25327]]

versus-speed map. Your measured T_test is the torque at which
the sum of the squares of normalized speed and power is maximum, as
follows:

T_test = T_i at the maximum of
(f_nnormi\2\ + P_normi\2\)

Eq. 1065.610-2

Where:

T_test = maximum test torque.

Example:
(f_nnorm1 = 1.002, P_norm1 = 0.978, T\1\ =
722.62 Nxm)
(f_nnorm2 = 1.004, P_norm2 = 0.977, T\2\ =
720.44 Nxm)
(f_nnorm3 = 1.006, P_norm3 = 0.974,
T3 = 716.80 Nxm)
(f_nnorm1\2\ + P_norm1\2\) = (1.002\2\ +
0.978\2\) = 1.960
(f_nnorm1\2\ + P_norm1\2\) = (1.004\2\ +
0.977\2\) = 1.963
(f_nnorm1\2\ + P_norm1\2\) = (1.006\2\ +
0.974\2\) = 1.961
maximum = 1.963 at i = 2
T_test = 720.44 Nxm

    (2) Transform normalized torques to reference torques according to
paragraph (d) of this section by using the measured maximum test torque
determined according to paragraph (b)(1) of this section--or use your
declared maximum test torque, as allowed in Sec.  1065.510.
    (c) Generating reference speed values from normalized duty cycle
speeds. Transform normalized speed values to reference values as
follows:
    (1) % speed. If your normalized duty cycle specifies % speed
values, use your warm idle speed and your maximum test speed to
transform the duty cycle, as follows:

f_nref = % speed [middot] (f_ntest -
f_nidle) + f_nidle

Eq. 1065.610-3

Example:

% speed = 85%
f_ntest = 2364 rev/min
f_nidle = 650 rev/min
f_nref = 85% [middot] (2364-650 ) + 650
f_nref = 2107 rev/min

    (2) A, B, and C speeds. If your normalized duty cycle specifies
speeds as A, B, or C values, use your power-versus-speed curve to
determine the lowest speed below maximum power at which 50% of maximum
power occurs. Denote this value as n_lo. Take n_lo
to be warm idle speed if all power points at speeds below the maximum
power speed are higher than 50% of maximum power. Also determine the
highest speed above maximum power at which 70% of maximum power occurs.
Denote this value as n_hi. If all power points at speeds
above the maximum power speed are higher than 70% of maximum power,
take n_hi to be the declared maximum safe engine speed or the
declared maximum representative engine speed, whichever is lower. Use
n_hi and n_lo to calculate reference values for A,
B, or C speeds as follows:
f_nrefA = 0.25 [middot] (n_hi-n_lo) +
n_lo

Eq. 1065.610-4

f_nrefB = 0.50 [middot] (n_hi - n_lo) +
n_lo

Eq. 1065.610-5
f_nrefC = 0.75 [middot] (n_hi - n_lo) +
n_lo
Eq. 1065.610-6

Example:

n_lo = 1005 rev/min
n_hi = 2385 rev/min
f_nrefA = 0.25 [middot] (2385-1005) + 1005
f_nrefB = 0.50 [middot] (2385-1005) + 1005
f_nrefC = 0.75 [middot] (2385-1005) + 1005
f_nrefA = 1350 rev/min
f_nrefB = 1695 rev/min
f_nrefC = 2040 rev/min

    (3) Intermediate speed. If your normalized duty cycle specifies a
speed as ``intermediate speed,'' use your torque-versus-speed curve to
determine the speed at which maximum torque occurs. This is peak torque
speed. Identify your reference intermediate speed as one of the
following values:
    (i) Peak torque speed if it is between (60 and 75)% of maximum test
speed.
    (ii) 60% of maximum test speed if peak torque speed is less than
60% of maximum test speed.
    (iii) 75% of maximum test speed if peak torque speed is greater
than 75% of maximum test speed.
    (d) Generating reference torques from normalized duty-cycle
torques. Transform normalized torques to reference torques using your
map of maximum torque versus speed.
    (1) Reference torque for variable-speed engines. For a given speed
point, multiply the corresponding % torque by the maximum torque at
that speed, according to your map. If your engine is subject to a
reference duty cycle that specifies negative torque values (i.e.,
engine motoring), use negative torque for those motoring points (i.e.,
the motoring torque). If you map negative torque as allowed under Sec. 
1065.510 (c)(2) and the low-speed governor activates, resulting in
positive torques, you may replace those positive motoring mapped
torques with negative values between zero and the largest negative
motoring torque. For both maximum and motoring torque maps, linearly
interpolate mapped torque values to determine torque between mapped
speeds. If the reference speed is below the minimum mapped speed (i.e.,
95% of idle speed or 95% of lowest required speed, whichever is
higher), use the mapped torque at the minimum mapped speed as the
reference torque. The result is the reference torque for each speed
point.
    (2) Reference torque for constant-speed engines. Multiply a %
torque value by your maximum test torque. The result is the reference
torque for each point.
    (3) Required deviations. We require the following deviations for
variable-speed engines intended primarily for propulsion of a vehicle
with an automatic transmission where that engine is subject to a
transient duty cycle with idle operation. These deviations are intended
to produce a more representative transient duty cycle for these
applications. For steady-state duty cycles or transient duty cycles
with no idle operation, these requirements do not apply. Idle points
for steady state duty cycles of such engines are to be run at
conditions simulating neutral or park on the transmission.
    (i) Zero-percent speed is the warm idle speed measured according to
Sec.  1065.510(b)(6) with CITT applied, i.e., measured warm idle speed
in drive.
    (ii) If the cycle begins with a set of contiguous idle points
(zero-percent speed, and zero-percent torque), leave the reference
torques set to zero for this initial contiguous idle segment. This is
to represent free idle operation with the transmission in neutral or
park at the start of the transient duty cycle, after the engine is
started. If the initial idle segment is longer than 24 s, change the
reference torques for the remaining idle points in the initial
contiguous idle segment to CITT (i.e., change idle points corresponding
to 25 s to the end of the initial idle segment to CITT). This is to
represent shifting the transmission to drive.
    (iii) For all other idle points, change the reference torque to
CITT. This is to represent the transmission operating in drive.
    (iv) If the engine is intended primarily for automatic
transmissions with a Neutral-When-Stationary feature that automatically
shifts the transmission to neutral after the vehicle is stopped for a
designated time and automatically shifts back to drive when the
operator increases demand (i.e., pushes the accelerator pedal), change
the reference torque back to zero for idle points in drive after the
designated time.
    (v) For all points with normalized speed at or below zero percent
and reference torque from zero to CITT, set the reference torque to
CITT. This is to provide smoother torque references below idle speed.
    (vi) For motoring points, make no changes.
    (vii) For consecutive points with reference torques from zero to
CITT that immediately follow idle points, change their reference
torques to CITT. This is to provide smooth torque transition out of
idle operation. This does not apply if the Neutral-When-Stationary
feature is used and the transmission has shifted to neutral.

[[Page 25328]]

    (viii) For consecutive points with reference torque from zero to
CITT that immediately precede idle points, change their reference
torques to CITT. This is to provide smooth torque transition into idle
operation.
    (4) Permissible deviations for any engine. If your engine does not
operate below a certain minimum torque under normal in-use conditions,
you may use a declared minimum torque as the reference value instead of
any value denormalized to be less than the declared value. For example,
if your engine is connected to a hydrostatic transmission and it has a
minimum torque even when all the driven hydraulic actuators and motors
are stationary and the engine is at idle, then you may use this
declared minimum torque as a reference torque value instead of any
reference torque value generated under paragraph (d)(1) or (2) of this
section that is between zero and this declared minimum torque.
    (e) Generating reference power values from normalized duty cycle
powers. Transform normalized power values to reference speed and power
values using your map of maximum power versus speed.
    (1) First transform normalized speed values into reference speed
values. For a given speed point, multiply the corresponding % power by
the mapped power at maximum test speed, f_ntest, unless
specified otherwise by the standard-setting part. The result is the
reference power for each speed point, P_ref. Convert these
reference powers to corresponding torques for operator demand and
dynamometer control and for duty cycle validation per 1065.514. Use the
reference speed associated with each reference power point for this
conversion. As with cycles specified with % torque, linearly
interpolate between these reference torque values generated from cycles
with % power.
    (2) Permissible deviations for any engine. If your engine does not
operate below a certain power under normal in-use conditions, you may
use a declared minimum power as the reference value instead of any
value denormalized to be less than the declared value. For example, if
your engine is directly connected to a propeller, it may have a minimum
power called idle power. In this case, you may use this declared
minimum power as a reference power value instead of any reference power
value generated per paragraph (e)(1) of this section that is from zero
to this declared minimum power.

• 111. Section 1065.640 is amended by revising paragraphs (a) and (e) and
redesignating the second ``Table 3'' as ``Table 4'' to read as follows:

Sec.  1065.640  Flow meter calibration calculations.

* * * * *
    (a) Reference meter conversions. The calibration equations in this
section use molar flow rate, n_ref, as a reference quantity.
If your reference meter outputs a flow rate in a different quantity,
such as standard volume rate, V_stdref, actual volume rate,
V_actref, or mass rate, m_ref, convert your
reference meter output to a molar flow rate using the following
equations, noting that while values for volume rate, mass rate,
pressure, temperature, and molar mass may change during an emission
test, you should ensure that they are as constant as practical for each
individual set point during a flow meter calibration:
[GRAPHIC] [TIFF OMITTED] TR06MY08.022

Where:
N_ref = reference molar flow rate.
V_stdref = reference volume flow rate, corrected to a
standard pressure and a standard temperature.
V_actref = reference volume flow rate at the actual
pressure and temperature of the flow rate.
N_ref = reference mass flow.
P_std = standard pressure.
P_act = actual pressure of the flow rate.
T_std = standard temperature.
T_act = actual temperature of the flow rate.
R = molar gas constant.
M_mix = molar mass of the flow rate.

Example 1:

V_stdref = 1000.00 ft3/min = 0.471948
m3/s
P = 29.9213 in Hg @ 32 [deg]F = 101325 Pa
T = 68.0 [deg]F = 293.15 K
R = 8.314472 J/(mol [middot] K)
[GRAPHIC] [TIFF OMITTED] TR06MY08.023

N_ref = 19.169 mol/s

Example 2:

M_ref = 17.2683 kg/min = 287.805 g/s
Mmix = 28.7805 g/mol
[GRAPHIC] [TIFF OMITTED] TR06MY08.024

    n_ref = 10.0000 mol/s

    (e) CFV calibration. Some CFV flow meters consist of a single
venturi and some consist of multiple venturis, where different
combinations of venturis are used to meter different flow rates. For
CFV flow meters that consist of multiple venturis, either calibrate
each venturi independently to determine a separate discharge
coefficient, Cd, for each venturi, or calibrate each combination of
venturis as one venturi. In the case where you calibrate a combination
of venturis, use the sum of the active venturi throat areas as At, the
square root of the sum of the squares of the active venturi throat
diameters as dt, and the ratio of the venturi throat to inlet diameters
as the ratio of the square root of the sum of the active venturi throat
diameters (dt) to the diameter of the common entrance to all of the
venturis (D). To determine the Cd for a single venturi or a single
combination of venturis, perform the following steps:
    (1) Use the data collected at each calibration set point to
calculate an individual Cd for each point using Eq. 1065.640-4.
    (2) Calculate the mean and standard deviation of all the Cd values
according to Eqs. 1065.602-1 and 1065.602-2.
    (3) If the standard deviation of all the Cd values is less than or
equal to 0.3% of the mean Cd, use the mean Cd in Eq. 1065.642-6, and
use the CFV only down to the lowest r measured during calibration using
the following equation:
[GRAPHIC] [TIFF OMITTED] TR06MY08.025

    (4) If the standard deviation of all the Cd values exceeds 0.3% of
the mean Cd, omit the Cd values corresponding to the data point
collected at the lowest r measured during calibration.
    (5) If the number of remaining data points is less than seven, take
corrective action by checking your calibration data or repeating the
calibration process. If you repeat the calibration process, we
recommend checking for leaks, applying tighter tolerances to
measurements and allowing more time for flows to stabilize.
    (6) If the number of remaining Cd values is seven or greater,
recalculate the mean and standard deviation of the remaining Cd values.
    (7) If the standard deviation of the remaining Cd values is less
than or equal to 0.3% of the mean of the remaining Cd, use that mean Cd
in Eq. 1065.642-6, and use the CFV values only down to the

[[Page 25329]]

lowest r associated with the remaining Cd.
    (8) If the standard deviation of the remaining Cd still exceeds
0.3% of the mean of the remaining Cd values, repeat the steps in
paragraph (e)(4) through (8) of this section.

• 112. Section 1065.642 is amended by revising paragraph (b) to read as
follows:

Sec.  1065.642  SSV, CFV, and PDP molar flow rate calculations.

    (b) SSV molar flow rate. Based on the Cd versus
Re# equation you determined according to Sec. 
1065.640, calculate SSV molar flow rate, n during an emission test as
follows:
[GRAPHIC] [TIFF OMITTED] TR06MY08.026

Example:

At = 0.01824 m\2\
pin = 99132 Pa
Z = 1
Mmix = 28.7805 g/mol = 0.0287805 kg/mol
R = 8.314472 J/(mol[middot]K)
Tin = 298.15 K
Re# = 7.232[middot]10\\
y = 1.399
[beta] = 0.8
[Delta]p = 2.312 kPa
Using Eq. 1065.640-7,
rssv = 0.997
Using Eq. 1065.640-6,
Cf = 0.274
Using Eq. 1065.640-5,
Cd = 0.990
[GRAPHIC] [TIFF OMITTED] TR06MY08.027

n= 58.173 mol/s

* * * * *

• 113. A new Sec.  1065.644 is added to read as follows:

Sec.  1065.644  Vacuum-decay leak rate.

    This section describes how to calculate the leak rate of a vacuum-
decay leak verification, which is described in Sec.  1065.345(e). Use
Eq. 1065.644-1 to calculate the leak rate, nleak, and compare it to the
criterion specified in Sec.  1065.345(e).

[GRAPHIC] [TIFF OMITTED] TR06MY08.028

Where:

V_vac = geometric volume of the vacuum-side of the
sampling system.
R = molar gas constant.
p\2\ = Vacuum-side absolute pressure at time t\2\.
T\2\ = Vacuum-side absolute temperature at time t\2\.
p\1\ = Vacuum-side absolute pressure at time t\1\.
T\1\ = Vacuum-side absolute temperature at time t\1\.
t\2\ = time at completion of vacuum-decay leak verification test.
t\1\ = time at start of vacuum-decay leak verification test.

Example:

V_vac = 2.0000 L = 0.00200 m3
R = 8.314472 J/(mol[middot]K)
p\2\ = 50.600 kPa = 50600 Pa
T\2\ = 293.15 K
p\1\ = 25.300 kPa = 25300 Pa
T\1\ = 293.15 K
t\2\ = 10:57:35 AM
t\1\ = 10:56:25 AM
[GRAPHIC] [TIFF OMITTED] TR06MY08.029

• 114. Section 1065.645 is revised to read as follows:

Sec.  1065.645  Amount of water in an ideal gas.

    This section describes how to determine the amount of water in an
ideal gas, which you need for various performance verifications and
emission calculations. Use the equation for the vapor pressure of water
in paragraph (a) of this section or another appropriate equation and,
depending on whether you measure dewpoint or relative humidity, perform
one of the calculations in paragraph (b) or (c) of this section.
    (a) Vapor pressure of water. Calculate the vapor pressure of water
for a given saturation temperature condition, T_sat, as
follows, or use good engineering judgment to use a different
relationship of the vapor pressure of water to a given saturation
temperature condition:
    (1) For humidity measurements made at ambient temperatures from (0
to 100) [deg]C, or for humidity measurements made over super-cooled
water at ambient temperatures from (-50 to 0) [deg]C, use the following
equation:

[[Page 25330]]

[GRAPHIC] [TIFF OMITTED] TR06MY08.030

Where:

P_H20 = vapor pressure of water at saturation temperature
condition, kPa.
T_sat = saturation temperature of water at measured
conditions, K.
Example:

T_sat = 9.5 [deg]C
T_dsat= 9.5 + 273.15 = 282.65 K
[GRAPHIC] [TIFF OMITTED] TR06MY08.112

-log₁₀(p_H20) = -0.073974
p_H20 = 100.073974 = 1.18569 kPa

    (2) For humidity measurements over ice at ambient temperatures from
(-100 to 0) [deg]C, use the following equation:
[GRAPHIC] [TIFF OMITTED] TR06MY08.031

Example:

T_ice = -15.4 [deg]C
T_ice = -15.4 + 273.15 = 257.75 K
[GRAPHIC] [TIFF OMITTED] TR06MY08.032

-log₁₀(p_H2O) =-0.79821
p_H2O = 100.79821 = 0.15914 kPa

    (b) Dewpoint. If you measure humidity as a dewpoint, determine the
amount of water in an ideal gas, x_H2O, as follows:
[GRAPHIC] [TIFF OMITTED] TR06MY08.033

Where:

x_H2O = amount of water in an ideal gas.
p_H2O = water vapor pressure at the measured dewpoint,
T_sat = T_dew.
p_abs = wet static absolute pressure at the location of
your dewpoint measurement.
Example:
p_abs = 99.980 kPa
T_sat = T_dew = 9.5 [deg]C
Using Eq. 1065.645-2,
p_H2O = 1.18489 kPa
x_H2O = 1.18489/99.980
x_H2O = 0.011851 mol/mol

    (c) Relative humidity. If you measure humidity as a relative
humidity, RH %, determine the amount of water in an ideal gas,
x_H2O, as follows:
[GRAPHIC] [TIFF OMITTED] TR06MY08.034

Where:

x_H2O = amount of water in an ideal gas.
RH % = relative humidity.
p_H2O = water vapor pressure at 100% relative humidity at
the location of your relative humidity measurement, T_sat
= T_amb.
p_abs = wet static absolute pressure at the location of
your relative humidity measurement.
Example:
RH % = 50.77%
p_abs = 99.980 kPa

[[Page 25331]]

T_sat = T_amb = 20 [deg]C
Using Eq. 1065.645-2,
p_H2O = 2.3371 kPa
x_H2O = (50.77% [middot]2.3371)/99.980
x_H2O = 0.011868 mol/mol

• 115. Section 1065.650 is revised to read as follows:

Sec.  1065.650  Emission calculations.

    (a) General. Calculate brake-specific emissions over each test
interval in a duty cycle. Refer to the standard-setting part for any
calculations you might need to determine a composite result, such as a
calculation that weights and sums the results of individual test
intervals in a duty cycle. For summations of continuous signals, each
indexed value (i.e., ``i'') represents (or approximates) the mean value
of the parameter for its respective time interval, delta-t.
    (b) We specify three alternative ways to calculate brake-specific
emissions, as follows:
    (1) For any testing, you may calculate the total mass of emissions,
as described in paragraph (c) of this section, and divide it by the
total work generated over the test interval, as described in paragraph
(d) of this section, using the following equation:

[GRAPHIC] [TIFF OMITTED] TR06MY08.035

Example:
m_NOx = 64.975 g
W = 25.783 kW[middot]hr
e_NOx = 64.975/25.783
e_NOx = 2.520 g/(kW[middot]hr)

    (2) For discrete-mode steady-state testing, you may calculate the
ratio of emission mass rate to power, as described in paragraph (e) of
this section, using the following equation:
[GRAPHIC] [TIFF OMITTED] TR06MY08.036

    (3) For field testing, you may calculate the ratio of total mass to
total work, where these individual values are determined as described
in paragraph (f) of this section. You may also use this approach for
laboratory testing, consistent with good engineering judgment. This is
a special case in which you use a signal linearly proportional to raw
exhaust molar flow rate to determine a value proportional to total
emissions. You then use the same linearly proportional signal to
determine total work using a chemical balance of fuel, intake air, and
exhaust as described in Sec.  1065.655, plus information about your
engine's brake-specific fuel consumption. Under this method, flow
meters need not meet accuracy specifications, but they must meet the
applicable linearity and repeatability specifications in subpart D or
subpart J of this part. The result is a brake-specific emission value
calculated as follows:
[GRAPHIC] [TIFF OMITTED] TR06MY08.037

Example:

m = 805.5 ~g
W = 52.102 ~kW[middot]hr
e_CO = 805.5/52.102
e_CO = 2.520 g/(kW[middot]hr)

    (c) Total mass of emissions. To calculate the total mass of an
emission, multiply a concentration by its respective flow. For all
systems, make preliminary calculations as described in paragraph (c)(1)
of this section, then use the method in paragraphs (c)(2) through (4)
of this section that is appropriate for your system. Calculate the
total mass of emissions as follows:
    (1) Concentration corrections. Perform the following sequence of
preliminary calculations on recorded concentrations:
    (i) Correct all THC and CH₄ concentrations, including
continuous readings, sample bags readings, and dilution air background
readings, for initial contamination, as described in Sec.  1065.660(a).
    (ii) Correct all concentrations measured on a ``dry'' basis to a
``wet'' basis, including dilution air background concentrations, as
described in Sec.  1065.659.
    (iii) Calculate all THC and NMHC concentrations, including dilution
air background concentrations, as described in Sec.  1065.660.
    (iv) For emission testing with an oxygenated fuel, calculate any HC
concentrations, including dilution air background concentrations, as
described in Sec.  1065.665. See subpart I of this part for testing
with oxygenated fuels.
    (v) Correct all the NO_X concentrations, including
dilution air background concentrations, for intake-air humidity as
described in Sec.  1065.670.
    (vi) Compare the background corrected mass of NMHC to background
corrected mass of THC. If the background corrected mass of NMHC is
greater than 0.98 times the background corrected mass of THC, take the
background corrected mass of NMHC to be 0.98 times the background
corrected mass of THC. If you omit the NMHC calculations as described
in Sec.  1065.660(b)(1), take the background corrected mass of NMHC to
be 0.98 times the background corrected mass of THC.
    (vii) Calculate brake-specific emissions before and after
correcting for drift, including dilution air background concentrations,
according to Sec.  1065.672.
    (2) Continuous sampling. For continuous sampling, you must
frequently record a continuously updated concentration signal. You may
measure this concentration from a changing flow rate or a constant flow
rate (including discrete-mode steady-state testing), as follows:
    (i) Varying flow rate. If you continuously sample from a changing
exhaust flow rate, time align and then multiply concentration
measurements by the flow rate from which you extracted it. Use good
engineering judgment to time align flow and concentration data to match
t₅₀ rise or fall times to within &plusmn;1 s. We
consider the following to be examples of changing flows that require a
continuous multiplication of concentration times molar flow rate: raw
exhaust, exhaust diluted with a constant flow rate of dilution air, and
CVS dilution with a CVS flowmeter that does not have an upstream heat
exchanger or electronic flow control. This multiplication results in
the flow rate of the emission itself. Integrate the emission flow rate
over a test interval to determine the total emission. If the total
emission is a molar quantity, convert this quantity to a mass by
multiplying it by its molar mass, M. The result is the mass of the
emission, m. Calculate m for continuous sampling with variable flow
using the following equations:
[GRAPHIC] [TIFF OMITTED] TR06MY08.038

Where:

[GRAPHIC] [TIFF OMITTED] TR06MY08.039

Example:

M_NMHC = 13.875389 g/mol
N = 1200
x_NMHC1 = 84.5 &mu;mol/mol = 84.5 [middot] 10-6
mol/mol
x_NMHC2 = 86.0 &mu;mol/mol = 86.0 [middot] 10-6
mol/mol
n_exh1 = 2.876 mol/s
n_exh2 = 2.224 mol/s
f_record = 1 Hz
Using Eq. 1065.650-5,
[Delta]t = 1/1 =1 s
m_NMHC = 13.875389 [middot] (84.5 [middot] 10-6
[middot] 2.876 + 86.0 [middot] 10-6 [middot] 2.224 + ...
+ x_NMHC1200 [middot] n_exh) [middot] 1
m_NMHC = 25.53 g

    (ii) Constant flow rate. If you continuously sample from a constant
exhaust flow rate, use the same emission calculations described in
paragraph (c)(2)(i) of this section or calculate the mean or flow-
weighted concentration recorded over the test interval and treat the
mean as a batch sample, as described in paragraph (c)(3)(ii) of this
section. We consider the following to be examples of constant

[[Page 25332]]

exhaust flows: CVS diluted exhaust with a CVS flowmeter that has either
an upstream heat exchanger, electronic flow control, or both.
    (3) Batch sampling. For batch sampling, the concentration is a
single value from a proportionally extracted batch sample (such as a
bag, filter, impinger, or cartridge). In this case, multiply the mean
concentration of the batch sample by the total flow from which the
sample was extracted. You may calculate total flow by integrating a
changing flow rate or by determining the mean of a constant flow rate,
as follows:
    (i) Varying flow rate. If you collect a batch sample from a
changing exhaust flow rate, extract a sample proportional to the
changing exhaust flow rate. We consider the following to be examples of
changing flows that require proportional sampling: Raw exhaust, exhaust
diluted with a constant flow rate of dilution air, and CVS dilution
with a CVS flowmeter that does not have an upstream heat exchanger or
electronic flow control. Integrate the flow rate over a test interval
to determine the total flow from which you extracted the proportional
sample. Multiply the mean concentration of the batch sample by the
total flow from which the sample was extracted. If the total emission
is a molar quantity, convert this quantity to a mass by multiplying it
by its molar mass, M. The result is the mass of the emission, m. In the
case of PM emissions, where the mean PM concentration is already in
units of mass per mole of sample, M_PM, simply multiply it by
the total flow. The result is the total mass of PM, m_PM.
Calculate m for batch sampling with variable flow using the following
equation:
[GRAPHIC] [TIFF OMITTED] TR06MY08.040

Example:

M_NOx = 46.0055 g/mol
N = 9000
x_NOx = 85.6 &mu;mol/mol = 85.6 [middot]
10-₆ mol/mol
n_dexh1 = 25.534 mol/s
n_dexh2 = 26.950 mol/s
f_record = 5 Hz
Using Eq. 1065.650-5,
[Delta]t = 1/5 = 0.2
m_NOx = 46.0055 [middot] 85.6 [middot]
10-₆ [middot] (25.534 + 26.950 + ... +
n_exh9000) [middot] 0.2
m_NOx = 4.201 g

    (ii) Constant flow rate. If you batch sample from a constant
exhaust flow rate, extract a sample at a proportional or constant flow
rate. We consider the following to be examples of constant exhaust
flows: CVS diluted exhaust with a CVS flow meter that has either an
upstream heat exchanger, electronic flow control, or both. Determine
the mean molar flow rate from which you extracted the constant flow
rate sample. Multiply the mean concentration of the batch sample by the
mean molar flow rate of the exhaust from which the sample was
extracted, and multiply the result by the time of the test interval. If
the total emission is a molar quantity, convert this quantity to a mass
by multiplying it by its molar mass, M. The result is the mass of the
emission, m. In the case of PM emissions, where the mean PM
concentration is already in units of mass per mole of sample,
M_PM, simply multiply it by the total flow, and the result is
the total mass of PM, m_PM. Calculate m for sampling with
constant flow using the following equations:
[GRAPHIC] [TIFF OMITTED] TR06MY08.041

and for PM or any other analysis of a batch sample that yields a mass
per mole of sample,
[GRAPHIC] [TIFF OMITTED] TR06MY08.042

Example:

M_PM = 144.0 &mu;g/mol = 144.0 [middot] 10-6 g/
mol
n_dexh = 57.692 mol/s
[Delta]t = 1200 s
m_PM = 144.0 [middot] 10-6 [middot] 57.692
[middot]1200
m_PM = 9.9692 g
    (4) Additional provisions for diluted exhaust sampling; continuous
or batch. The following additional provisions apply for sampling
emissions from diluted exhaust:
    (i) For sampling with a constant dilution ratio (DR) of diluted
exhaust versus exhaust flow (e.g., secondary dilution for PM sampling),
calculate m using the following equation:
[GRAPHIC] [TIFF OMITTED] TR06MY08.043

Example:

m_PMdil = 6.853 g
DR = 6:1
m_PM = 6.853 [middot] (6)
m_PM = 41.118 g

    (ii) For continuous or batch sampling, you may measure background
emissions in the dilution air. You may then subtract the measured
background emissions, as described in Sec.  1065.667.
    (d) Total work. To calculate total work from the engine's primary
output shaft, numerically integrate feedback power over a test
interval. Before integrating, adjust the speed and torque data for the
time alignment used in Sec.  1065.514(c). Any advance or delay used on
the feedback signals for cycle validation must also be used for
calculating work. Account for work of accessories according to Sec. 
1065.110. Exclude any work during cranking and starting. Exclude work
during actual motoring operation (negative feedback torques), unless
the engine was connected to one or more energy storage devices.
Examples of such energy storage devices include hybrid powertrain
batteries and hydraulic accumulators, like the ones illustrated in
Figure 1 of Sec.  1065.210. Exclude any work during reference zero-load
idle periods (0% speed or idle speed with 0 N[middot]m reference
torque). Note, that there must be two consecutive reference zero load
idle points to establish a period where this applies. Include work
during idle points with simulated minimum torque such as Curb Idle
Transmissions Torque (CITT) for automatic transmissions in ``drive''.
The work calculation method described in paragraphs (b)(1) though (7)
of this section meets these requirements using rectangular integration.
You may use other logic that gives equivalent results. For example, you
may use a trapezoidal integration method as described in paragraph
(b)(8) of this section.
    (1) Time align the recorded feedback speed and torque values by the
amount used in Sec.  1065.514(c).
    (2) Calculate shaft power at each point during the test interval by
multiplying all the recorded feedback engine speeds by their respective
feedback torques.
    (3) Adjust (reduce) the shaft power values for accessories
according to Sec.  1065.110.
    (4) Set all power values during any cranking or starting period to
zero. See Sec.  1065.525 for more information about engine cranking.
    (5) Set all negative power values to zero, unless the engine was
connected to one or more energy storage devices. If the engine was
tested with an energy storage device, leave negative power values
unaltered.
    (6) Set all power values to zero during idle periods with a
corresponding reference torque of 0 N[middot]m.
    (7) Integrate the resulting values for power over the test
interval. Calculate total work as follows:
[GRAPHIC] [TIFF OMITTED] TR06MY08.044
[GRAPHIC] [TIFF OMITTED] TR06MY08.045

Example:

N = 9000
f_n1 = 1800.2 rev/min
f_n2 = 1805.8 rev/min
T₁ = 177.23 N[middot]m
T₂ = 175.00 N[middot]m
C_rev = 2 [middot] [pi] rad/rev
C_t1 = 60 s/min
C_p = 1000 (N[middot]m[middot]rad/s)/kW
f_record = 5 Hz
C_t2 = 3600 s/hr

[[Page 25333]]
[GRAPHIC] [TIFF OMITTED] TR06MY08.046

P₁ = 33.41 kW
P₂ = 33.09 kW
Using Eq. 1065.650-5,
[Delta]t = \1/5\ = 0.2 s
[GRAPHIC] [TIFF OMITTED] TR06MY08.047

W = 16.875 kW[middot]hr

    (8) You may use a trapezoidal integration method instead of the
rectangular integration described in this paragraph (b). To do this,
you must integrate the fraction of work between points where the torque
is positive. You may assume that speed and torque are linear between
data points. You may not set negative values to zero before running the
integration.
    (e) Steady-state mass rate divided by power. To determine steady-
state brake-specific emissions for a test interval as described in
paragraph (b)(2) of this section, calculate the mean steady-state mass
rate of the emission, m, and the mean steady-state power, P as follows:
    (1) To calculate m, multiply its mean concentration, x, by its
corresponding mean molar flow rate, n. If the result is a molar flow
rate, convert this quantity to a mass rate by multiplying it by its
molar mass, M. The result is the mean mass rate of the emission, m. In
the case of PM emissions, where the mean PM concentration is already in
units of mass per mole of sample, M_PM, simply multiply it by
the mean molar flow rate, n. The result is the mass rate of PM,
m_PM. Calculate m using the following equation:
[GRAPHIC] [TIFF OMITTED] TR06MY08.048

    (2) Calculate P using the following equation:
    [GRAPHIC] [TIFF OMITTED] TR06MY08.049
   
    (3) Divide emission mass rate by power to calculate a brake-
specific emission result as described in paragraph (b)(2) of this section.
    (4) The following example shows how to calculate mass of emissions
using mean mass rate and mean power:

M_CO = 28.0101 g/mol
x_CO = 12.00 mmol/mol = 0.01200 mol/mol
n = 1.530 mol/s
f_n = 3584.5 rev/min = 375.37 rad/s
T = 121.50 N[middot]m
m = 28.0101[middot]0.01200[middot]1.530
m = 0.514 g/s = 1850.4 g/hr
P = 121.5[middot]375.37
P = 45607
W = 45.607 kW
e_CO = 1850.4/45.61
e_CO = 40.57 g/(kW[middot]hr)

    (f) Ratio of total mass of emissions to total work. To determine
brake-specific emissions for a test interval as described in paragraph
(b)(3) of this section, calculate a value proportional to the total
mass of each emission. Divide each proportional value by a value that
is similarly proportional to total work.
    (1) Total mass. To determine a value proportional to the total mass
of an emission, determine total mass as described in paragraph (c) of
this section, except substitute for the molar flow rate, n, or the
total flow, n, with a signal that is linearly proportional to molar
flow rate, ñ, or linearly proportional to total flow, ñ,
as follows:
[GRAPHIC] [TIFF OMITTED] TR06MY08.050

    (2) Total work. To calculate a value proportional to total work
over a test interval, integrate a value that is proportional to power.
Use information about the brake-specific fuel consumption of your
engine, e_fuel, to convert a signal proportional to fuel flow
rate to a signal proportional to power. To determine a signal
proportional to fuel flow rate, divide a signal that is proportional to
the mass rate of carbon products by the fraction of carbon in your
fuel, w_c.. For your fuel, you may use a measured
w_c or you may use the default values in Table 1 of Sec. 
1065.655. Calculate the mass rate of carbon from the amount of carbon
and water in the exhaust, which you determine with a chemical balance
of fuel, intake air, and exhaust as described in Sec.  1065.655. In the
chemical balance, you must use concentrations from the flow that
generated the signal proportional to molar flow rate, n~, in paragraph
(e)(1) of this section. Calculate a value proportional to total work as
follows:
[GRAPHIC] [TIFF OMITTED] TR06MY08.051

Where:
[GRAPHIC] [TIFF OMITTED] TR06MY08.052

    (3) Brake-specific emissions. Divide the value proportional to
total mass by the value proportional to total work to determine brake-
specific emissions, as described in paragraph (b)(3) of this section.
    (4) Example. The following example shows how to calculate mass of
emissions using proportional values:

N = 3000
f_record = 5 Hz
e_fuel = 285 g/(kW.hr)
w_fuel = 0.869 g/g
M_c = 12.0107 g/mol
n₁ = 3.922 ~mol/s = 14119.2 mol/hr
x_Ccombdry1 = 91.634 mmol/mol = 0.091634 mol/mol
x_H2Oexh1 = 27.21 mmol/mol = 0.02721 mol/mol

Using Eq. 1065.650-5,
[Delta]t = 0.2 s

[GRAPHIC] [TIFF OMITTED] TR06MY08.053

W = 5.09 ~(kW[middot]hr)

    (g) Rounding. Round emission values only after all calculations are
complete and the result is in g/(kW[middot]hr) or units equivalent to
the units of the standard, such as g/(hp[middot]hr). See the definition
of ``Round'' in Sec.  1065.1001.

• 116. Section 1065.655 is revised to read as follows:

[[Page 25334]]

Sec.  1065.655  Chemical balances of fuel, intake air, and exhaust.

    (a) General. Chemical balances of fuel, intake air, and exhaust may
be used to calculate flows, the amount of water in their flows, and the
wet concentration of constituents in their flows. With one flow rate of
either fuel, intake air, or exhaust, you may use chemical balances to
determine the flows of the other two. For example, you may use chemical
balances along with either intake air or fuel flow to determine raw
exhaust flow.
    (b) Procedures that require chemical balances. We require chemical
balances when you determine the following:
    (1) A value proportional to total work, W, when you choose to
determine brake-specific emissions as described in Sec.  1065.650(e).
    (2) The amount of water in a raw or diluted exhaust flow,
x_H2Oexh, when you do not measure the amount of water to
correct for the amount of water removed by a sampling system. Correct
for removed water according to Sec.  1065.659(c)(2).
    (3) The flow-weighted mean fraction of dilution air in diluted
exhaust, x_dil/exh, when you do not measure dilution air flow
to correct for background emissions as described in Sec.  1065.667(c).
Note that if you use chemical balances for this purpose, you are
assuming that your exhaust is stoichiometric, even if it is not.
    (c) Chemical balance procedure. The calculations for a chemical
balance involve a system of equations that require iteration. We
recommend using a computer to solve this system of equations. You must
guess the initial values of up to three quantities: The amount of water
in the measured flow, x_H2Oexh, fraction of dilution air in
diluted exhaust, x_dil/exh, and the amount of products on a
C₁ basis per dry mole of dry measured flow,
x_Ccombdry. You may use time-weighted mean values of
combustion air humidity and dilution air humidity in the chemical
balance; as long as your combustion air and dilution air humidities
remain within tolerances of &plusmn; 0.0025 mol/mol of their
respective mean values over the test interval. For each emission
concentration, x, and amount of water, x_H2Oexh, you must
determine their completely dry concentrations, x_dry and
x_H2Oexhdry. You must also use your fuel's atomic hydrogen-
to-carbon ratio, [alpha], and oxygen-to-carbon ratio, [beta]. For your
fuel, you may measure [alpha] and [beta] or you may use the default
values in Table 1 of Sec.  1065.650. Use the following steps to
complete a chemical balance:
    (1) Convert your measured concentrations such as,
x_CO2meas, x_NOmeas, and x_H2Oint, to dry
concentrations by dividing them by one minus the amount of water
present during their respective measurements; for example:
x_H2OxCO2meas, x_H2OxNOmeas, and
x_H2Oint. If the amount of water present during a ``wet''
measurement is the same as the unknown amount of water in the exhaust
flow, x_H2Oexh, iteratively solve for that value in the
system of equations. If you measure only total NO_X and not
NO and NO₂ separately, use good engineering judgment to
estimate a split in your total NO_X concentration between NO
and NO₂ for the chemical balances. For example, if you
measure emissions from a stoichiometric spark-ignition engine, you may
assume all NO_X is NO. For a compression-ignition engine, you
may assume that your molar concentration of NO_X,
x_NOx, is 75% NO and 25% NO₂. For NO₂
storage aftertreatment systems, you may assume x_NOx is 25%
NO and 75% NO\2\. Note that for calculating the mass of NO_X
emissions, you must use the molar mass of NO₂ for the
effective molar mass of all NO_X species, regardless of the
actual NO₂ fraction of NO_X.
    (2) Enter the equations in paragraph (c)(4) of this section into a
computer program to iteratively solve for x_H2Oexh,
x_Ccombdry, and x_dil/exh. Use good engineering
judgment to guess initial values for x_H2Oexh,
x_Ccombdry, and x_dil/exh. We recommend guessing an
initial amount of water that is about twice the amount of water in your
intake or dilution air. We recommend guessing an initial value of
x_Ccombdry as the sum of your measured CO₂, CO,
and THC values. We also recommend guessing an initial
x_dil/exh between 0.75 and 0.95, such as 0.8. Iterate values
in the system of equations until the most recently updated guesses are
all within &plusmn; 1% of their respective most recently calculated
values.
    (3) Use the following symbols and subscripts in the equations for
this paragraph (c):

x_dil/exh = Amount of dilution gas or excess air per mole
of exhaust.
x_H2Oexh = Amount of water in exhaust per mole of exhaust.
x_Ccombdry = Amount of carbon from fuel in the exhaust per
mole of dry exhaust.
x_H2Oexhdry = Amount of water in exhaust per dry mole of
dry exhaust.
x_prod/intdry = Amount of dry stoichiometric products per
dry mole of intake air.
x_dil/exh_dry = Amount of dilution gas and/or
excess air per mole of dry exhaust.
x_int/exhdry = Amount of intake air required to produce
actual combustion products per mole of dry (raw or diluted) exhaust.
x_raw/exhdry = Amount of undiluted exhaust, without excess
air, per mole of dry (raw or diluted) exhaust.
x_O2int = Amount of intake air O₂ per mole of
intake air.
x_CO2intdry = Amount of intake air CO₂ per mole
of dry intake air. You may use x_CO2intdry = 375 &mu;mol/
mol, but we recommend measuring the actual concentration in the
intake air.
x_H2Ointdry = Amount of intake air H₂O per mole
of dry intake air.
x_CO2int = Amount of intake air CO₂ per mole of
intake air.
x_CO2dil = Amount of dilution gas CO₂ per mole
of dilution gas.
x_CO2dildry = Amount of dilution gas CO₂ per
mole of dry dilution gas. If you use air as diluent, you may use
x_CO2dildry = 375 &mu;mol/mol, but we recommend measuring
the actual concentration in the intake air.
x_H2Odildry = Amount of dilution gas H₂O per
mole of dry dilution gas.
x_H2Odil = Amount of dilution gas H₂O per mole
of dilution gas.
x_{[emission]meas} = Amount of measured emission in the
sample at the respective gas analyzer.
x_{[emission]dry} = Amount of emission per dry mole of dry sample.
x_{H2O[emission]meas} = Amount of water in sample at
emission-detection location. Measure or estimate these values
according to Sec.  1065.145(d)(2).
x_H2Oint = Amount of water in the intake air, based on a
humidity measurement of intake air.
[alpha] = Atomic hydrogen-to-carbon ratio in fuel.
[beta] = Atomic oxygen-to-carbon ratio in fuel.

    (4) Use the following equations to iteratively solve for
x_dil/exh, x_H2Oexh, and x_Ccombdry:
[GRAPHIC] [TIFF OMITTED] TR06MY08.054
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    (5) The following example is a solution for x_dil/exh,
x_H2Oexh, and x_Ccombdry using the equations in
paragraph (c)(4) of this section:
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[alpha] = 1.8
[beta] = 0.05

[[Page 25337]]

Table 1 of Sec.   1065.655.--Default Values of Atomic Hydrogen-to-Carbon Ratio, [alpha], Atomic Oxygen-to-Carbon
                     Ratio, [beta], and Carbon Mass Fraction of Fuel, wC, for Various Fuels
----------------------------------------------------------------------------------------------------------------
                                                                                                   Carbon mass
                      Fuel                           Atomic  hydrogen and  oxygen-to-carbon      concentration,
                                                            ratios  CH[alpha]O[beta]                 wC  g/g
----------------------------------------------------------------------------------------------------------------
Gasoline........................................  CH1.85O0                                                 0.866
#2 Diesel...............................  CH1.80O0                                                 0.869
#1 Diesel...............................  CH1.93O0                                                 0.861
Liquified Petroleum Gas.........................  CH2.64O0                                                 0.819
Natural gas.....................................  CH3.78O0.016                                             0.747
Ethanol.........................................  CH3O0.5                                                  0.521
Methanol........................................  CH4O1                                                    0.375
----------------------------------------------------------------------------------------------------------------

    (d) Calculated raw exhaust molar flow rate from measured intake air
molar flow rate or fuel mass flow rate. You may calculate the raw
exhaust molar flow rate from which you sampled emissions,
n_exh, based on the measured intake air molar flow rate,
n_int, or the measured fuel mass flow rate, n_fuel,
and the values calculated using the chemical balance in paragraph (c)
of this section. Note that the chemical balance must be based on raw
exhaust gas concentrations. Solve for the chemical balance in paragraph
(c) of this section at the same frequency that you update and record
n_intor n_fuel.
    (1) Crankcase flow rate. If engines are not subject to crankcase
controls under the standard-setting part, you may calculate raw exhaust
flow based on n_intor n_fuel using one of the following:
    (i) You may measure flow rate through the crankcase vent and
subtract it from the calculated exhaust flow.
    (ii) You may estimate flow rate through the crankcase vent by
engineering analysis as long as the uncertainty in your calculation
does not adversely affect your ability to show that your engines comply
with applicable emission standards.
    (iii) You may assume your crankcase vent flow rate is zero.
    (2) Intake air molar flow rate calculation. Based on
n_int, calculate n_exh as follows:
[GRAPHIC] [TIFF OMITTED] TR06MY08.088

Where:

n_exh = raw exhaust molar flow rate from which you
measured emissions.
n_int = intake air molar flow rate including humidity in
intake air.

Example:

n_int = 3.780 mol/s
x_int/exhdry = 0.69021 mol/mol
x_raw/exhdry = 1.10764 mol/mol
x_H20exhdry = 107.64 mmol/mol = 0.10764 mol/mol
[GRAPHIC] [TIFF OMITTED] TR06MY08.089

n_exh = 6.066 mol/s

    (3) Fuel mass flow rate calculation. Based on m_fuel,
calculate n_exh as follows:
[GRAPHIC] [TIFF OMITTED] TR06MY08.090

Where:

n_exh = raw exhaust molar flow rate from which you
measured emissions.
m_fuel = fuel flow rate including humidity in intake air.

Example:

m_fuel = 7.559 g/s
w_C = 0.869 g/g
M_C = 12.0107 g/mol
x_Ccombdry = 99.87 mmol/mol = 0.09987 mol/mol
x_H20exhdry = 107.64 mmol/mol = 0.10764 mol/mol
[GRAPHIC] [TIFF OMITTED] TR06MY08.091

[[Page 25338]]

n_exh = 6.066 mol/s

• 117. Section 1065.659 is revised to read as follows:

Sec.  1065.659  Removed water correction.

    (a) If you remove water upstream of a concentration measurement, x,
or upstream of a flow measurement, n, correct for the removed water.
Perform this correction based on the amount of water at the
concentration measurement, x_{H2O[emission]meas}, and at the
flow meter, x_H2Oexh, whose flow is used to determine the
concentration's total mass over a test interval.
    (b) When using continuous analyzers downstream of a sample dryer
for transient and ramped-modal testing, you must correct for removed
water using signals from other continuous analyzers. When using batch
analyzers downstream of a sample dryer, you must correct for removed
water by using signals either from other batch analyzers or from the
flow-weighted average concentrations from continuous analyzers.
Downstream of where you removed water, you may determine the amount of
water remaining by any of the following:
    (1) Measure the dewpoint and absolute pressure downstream of the
water removal location and calculate the amount of water remaining as
described in Sec.  1065.645.
    (2) When saturated water vapor conditions exist at a given
location, you may use the measured temperature at that location as the
dewpoint for the downstream flow. If we ask, you must demonstrate how
you know that saturated water vapor conditions exist. Use good
engineering judgment to measure the temperature at the appropriate
location to accurately reflect the dewpoint of the flow. Note that if
you use this option and the water correction in paragraph (d) of this
section results in a corrected value that is greater than the measured
value, your saturation assumption is invalid and you must determine the
water content according to paragraph (b)(1) of this section.
    (3) You may also use a nominal value of absolute pressure based on
an alarm set point, a pressure regulator set point, or good engineering
judgment.
    (4) Set x_{H2O[emission]meas} equal to that of the measured
upstream humidity condition if it is lower than the dryer saturation
conditions.
    (c) For a corresponding concentration or flow measurement where you
did not remove water, you may determine the amount of initial water by
any of the following:
    (1) Use any of the techniques described in paragraph (b) of this
section.
    (2) If the measurement comes from raw exhaust, you may determine
the amount of water based on intake-air humidity, plus a chemical
balance of fuel, intake air and exhaust as described in Sec.  1065.655.
    (3) If the measurement comes from diluted exhaust, you may
determine the amount of water based on intake-air humidity, dilution
air humidity, and a chemical balance of fuel, intake air, and exhaust
as described in Sec.  1065.655.
    (d) Perform a removed water correction to the concentration
measurement using the following equation:
[GRAPHIC] [TIFF OMITTED] TR06MY08.092

Example:

x_COmeas = 29.0 &mu;mol/mol
x_H2OCOmeas = 8.601 mmol/mol = 0.008601 mol/mol
x_H2Oexh = 34.04 mmol/mol = 0.03404 mol/mol
[GRAPHIC] [TIFF OMITTED] TR06MY08.093

x_CO = 28.3 &mu;mol/mol

• 118. Section 1065.660 is revised to read as follows:

Sec.  1065.660  THC and NMHC determination.

    (a) THC determination and THC/CH4 initial contamination
corrections. (1) If we require you to determine THC emissions,
calculate x_THC[THC-FID] using the initial THC contamination
concentration x_{THC[THC-FID]init} from Sec.  1065.520 as follows:
[GRAPHIC] [TIFF OMITTED] TR06MY08.094

Example:

x_THCuncor = 150.3 &mu;mol/mol
x_THCinit = 1.1 &mu;mol/mol
x_THCcor = 150.3 - 1.1
x_THCcor = 149.2 &mu;mol/mol

    (2) For the NMHC determination described in paragraph (b) of this
section, correct x_THC[THC-FID] for initial HC contamination
using Eq. 1065.660-1. You may correct for initial contamination of the
CH₄ sample train using Eq. 1065.660-1, substituting in
CH₄ concentrations for THC.
    (b) NMHC determination. Use one of the following to determine NMHC
concentration, x_NMHC:
    (1) If you do not measure CH₄, you may determine NMHC
concentrations as described in Sec.  1065.650(c)(1)(vi).
    (2) For nonmethane cutters, calculate x_NMHC using the
nonmethane cutter's penetration fractions (PF) of CH₄ and
C₂H₆ from Sec.  1065.365, and using the HC
contamination and wet-to-dry corrected THC concentration
x_{THC[THC-FID]cor} as determined in paragraph (a) of this
section.
    (i) Use the following equation for penetration fractions determined
using an NMC configuration as outlined in Sec.  1065.365(d):
[GRAPHIC] [TIFF OMITTED] TR06MY08.095

[[Page 25339]]

Where:

x_NMHC = concentration of NMHC.
x_{THC[THC-FID]cor} = concentration of THC, HC contamination
and dry-to-wet corrected, as measured by the THC FID during sampling
while bypassing the NMC.
x_THC[NMC-FID] = concentration of THC, HC contamination
(optional) and dry-to-wet corrected, as measured by the THC FID
during sampling through the NMC.
RF_CH4[THC-FID] = response factor of THC FID to
CH₄, according to Sec.  1065.360(d).
RFPF_{C2H6[NMC-FID]} = nonmethane cutter combined ethane
response factor and penetration fraction, according to Sec.  1065.365(d).

Example:

x_{THC[THC-FID]cor} = 150.3 &mu;mol/mol
x_THC[NMC-FID] = 20.5 &mu;mol/mol
RFPF_{C2H6[NMC-FID]} = 0.019
RF_CH4[THC-FID] = 1.05
[GRAPHIC] [TIFF OMITTED] TR06MY08.096

x_NMHC = 130.4 &mu;mol/mol

    (ii) For penetration fractions determined using an NMC
configuration as outlined in Sec.  1065.365(e), use the following equation:
[GRAPHIC] [TIFF OMITTED] TR06MY08.097

Where:

x_NMHC = concentration of NMHC.
x_{THC[THC-FID]cor} = concentration of THC, HC contamination
and dry-to-wet corrected, as measured by the THC FID during sampling
while bypassing the NMC.
PF_CH4[NMC-FID] = nonmethane cutter CH₄
penetration fraction, according to Sec.  1065.365(e).
x_THC[NMC-FID] = concentration of THC, HC contamination
(optional) and dry-to-wet corrected, as measured by the THC FID
during sampling through the NMC.
PF_{C2H6[NMC-FID]} = nonmethane cutter ethane penetration
fraction, according to Sec.  1065.365(e).

Example:

x_{THC[THC-FID]cor} = 150.3 &mu;mol/mol
PF_CH4[NMC-FID] = 0.990
x_THC[NMC-FID] = 20.5 &mu;mol/mol
PF_{C2H6[NMC-FID]} = 0.020
[GRAPHIC] [TIFF OMITTED] TR06MY08.098

x_NMHC = 132.3 &mu;mol/mol

    (iii) For penetration fractions determined using an NMC
configuration as outlined in Sec.  1065.365(f), use the following equation:
[GRAPHIC] [TIFF OMITTED] TR06MY08.099

Where:

x_NMHC = concentration of NMHC.
x_{THC[THC-FID]cor} = concentration of THC, HC contamination
and dry-to-wet corrected, as measured by the THC FID during sampling
while bypassing the NMC.
PF_CH4[NMC-FID] = nonmethane cutter CH₄
penetration fraction, according to Sec.  1065.365(f).
x_THC[NMC-FID] = concentration of THC, HC contamination
(optional) and dry-to-wet corrected, as measured by the THC FID
during sampling through the NMC.
RFPF_{C2H6[NMC-FID]} = nonmethane cutter CH₄
combined ethane response factor and penetration fraction, according
to Sec.  1065.365(f).
RF_CH4[THC-FID] = response factor of THC FID to
CH₄, according to Sec.  1065.360(d).

Example:

x_{THC[THC-FID]cor} = 150.3 &mu;mol/mol
PF_CH4[NMC-FID] = 0.990
x_THC[NMC-FID] = 20.5 &mu;mol/mol
RFPF_{C2H6[NMC-FID]} = 0.019
RF_CH4[THC-FID] = 0.980
[GRAPHIC] [TIFF OMITTED] TR06MY08.100

x_NMHC = 132.5 &mu;mol/mol

    (3) For a gas chromatograph, calculate x_NMHC using the
THC analyzer's response factor (RF) for CH₄, from Sec. 
1065.360, and the HC contamination and wet-to-dry corrected initial THC
concentration x_{THC[THC-FID]cor} as determined in section (a)
above as follows:
[GRAPHIC] [TIFF OMITTED] TR06MY08.101

Where:

x_NMHC = concentration of NMHC.
x_{THC[THC-FID]cor} = concentration of THC, HC contamination
and dry-to-wet corrected, as measured by the THC FID.
x_CH4 = concentration of CH₄, HC contamination
(optional) and dry-to-wet corrected, as measured by the gas
chromatograph FID.
RF_CH4[THC-FID] = response factor of THC-FID to
CH₄.

Example:

x_{THC[THC-FID][cor} = 145.6 &mu;mol/mol
RF_CH4[THC-FID] = 0.970
x_CH4 = 18.9 &mu;mol/mol
x_NMHC = 145.6-0.970 [middot] 18.9
x_NMHC = 127.3 &mu;mol/mol

• 119. Section 1065.665 is revised to read as follows:

Sec.  1065.665  THCE and NMHCE determination.

    (a) If you measured an oxygenated hydrocarbon's mass concentration,
first calculate its molar concentration in the exhaust sample stream
from which the sample was taken (raw or diluted exhaust), and convert
this into a C₁-equivalent molar concentration. Add these
C₁-equivalent molar concentrations to the molar
concentration of NOTHC. The result is the molar concentration of THCE.
Calculate THCE concentration using the following equations, noting that
equation 1065.665-3 is only required if you need to convert your OHC
concentration from mass to moles:

[[Page 25340]]
[GRAPHIC] [TIFF OMITTED] TR06MY08.102
[GRAPHIC] [TIFF OMITTED] TR06MY08.103
[GRAPHIC] [TIFF OMITTED] TR06MY08.104

Where:

x_THCE = The C₁-equivalent sum of the
concentration of carbon mass contributions of non-oxygenated
hydrocarbons, alcohols, and aldehydes.
x_NOTHC = The C₁-equivalent sum of the
concentration of nonoxygenated THC.
x_OHCi = The C₁-equivalent concentration of
oxygenated species i in diluted exhaust, not corrected for initial
contamination.
x_OHCi-init = The C₁-equivalent concentration
of the initial system contamination (optional) of oxygenated species
i, dry-to-wet corrected.
x_{THC[THC-FID]cor} = The C₁-equivalent response
to NOTHC and all OHC in diluted exhaust, HC contamination and dry-
to-wet corrected, as measured by the THC-FID.
RF_{OHCi[THC-FID]} = The response factor of the FID to
species i relative to propane on a C₁-equivalent basis.
C# = The mean number of carbon atoms in the particular compound.
M_dexh = The molar mass of diluted exhaust as determined
in Sec.  1065.340.
m_dexhOHCi = The mass of oxygenated species i in dilute exhaust.
M_OHCi = The C₁-equivalent molecular weight of
oxygenated species i.
m_dexh = The mass of diluted exhaust.
n_dexhOHCi = The number of moles of oxygenated species i
in total diluted exhaust flow.
n_dexh = The total diluted exhaust flow.

    (b) If we require you to determine NMHCE, use the following equation:
[GRAPHIC] [TIFF OMITTED] TR06MY08.105

Where:

x_NMHCE = The C₁-equivalent sum of the
concentration of carbon mass contributions of non-oxygenated NMHC,
alcohols, and aldehydes.
RF_CH4[THC-FID] = response factor of THC-FID to
CH₄.
x_CH4 = concentration of CH₄, HC contamination (optional) and
dry-to-wet corrected, as measured by the gas chromatograph FID.

    (c) The following example shows how to determine NMHCE emissions
based on ethanol (C₂H₅OH), methanol
(CH₃OH), acetaldehyde (C₂H₄O), and
formaldehyde (HCHO) as C₁-equivalent molar concentrations:

x_{THC[THC-FID]cor} = 145.6 &mu;mol/mol
x_CH4 = 18.9 &mu;mol/mol
x_C2H5OH = 100.8 &mu;mol/mol
x_CH3OH = 1.1 &mu;mol/mol
x_C2H4O = 19.1 &mu;mol/mol
x_HCHO = 1.3 &mu;mol/mol
RF_CH4[THC-FID] = 1.07
RF_{C2H5OH[THC-FID]} = 0.76
RF_{CH3OH[THC-FID]} = 0.74
RF_{H2H4O[THC-FID]} = 0.50
RF_{HCHO[THC-FID]} = 0.0
x_NMHCE = x_{THC[THC-FID]cor}-(x_C2H5OH
[middot] RF_{C2H5OH[THC-FID]} + x_CH3OH [middot]
RF_{CH3OH[THC-FID]} + x_C2H4O [middot]
RF_{C2H4O[THC-FID]} + x_HCHO [middot]
RF_{HCHO[THC-FID]} + x_C2H5OH + x_CH3OH +
x_C2H4O + x_HCHO-(RF_CH4[THC-FID]
[middot] x_CH4)
x_NMHCE = 145.6-(100.8 [middot] 0.76 + 1.1 [middot] 0.74 +
19.1 [middot] 0.50 + 1.3 [middot] 0) + 100.8 + 1.1 + 19.1 + 1.3-(1.07
[middot] 18.9)
x_NMHCE = 160.71 &mu;mol/mol

• 120. Section 1065.667 is amended by revising paragraph (b) to read as
follows:

Sec.  1065.667  Dilution air background emission correction.

* * * * *
    (b) You may determine the total flow of dilution air by a direct
flow measurement. In this case, calculate the total mass of background
as described in Sec.  1065.650(b), using the dilution air flow,
n_dil. Subtract the background mass from the total mass. Use
the result in brake-specific emission calculations.
* * * * *
• 121. Section 1065.670 is amended by revising the introductory text to
read as follows:

Sec.  1065.670  NOX intake-air humidity and temperature corrections.

    See the standard-setting part to determine if you may correct
NO_X emissions for the effects of intake-air humidity or
temperature. Use the NO_X intake-air humidity and temperature
corrections specified in the standard-setting part instead of the
NO_X intake-air humidity correction specified in this part
1065. If the standard-setting part does not prohibit correcting
NO_X emissions for intake-air humidity according to this part
1065, first apply any NO_X corrections for background
emissions and water removal from the exhaust sample, then correct
NO_X concentrations for intake-air humidity. You may use a
time-weighted mean combustion air humidity to calculate this correction
if your combustion air humidity remains within a tolerance of
&plusmn; 0.0025 mol/mol of the mean value over the test interval. For
intake-air humidity correction, use one of the following approaches:
* * * * *
• 122. Section 1065.675 is revised to read as follows:

Sec.  1065.675  CLD quench verification calculations.

    Perform CLD quench-check calculations as follows:
    (a) Calculate the amount of water in the span gas,
x_H2Ospan, assuming

[[Page 25341]]

complete saturation at the span-gas temperature.
    (b) Estimate the expected amount of water and CO₂ in the
exhaust you sample, x_H2Oexp and x_CO2exp,
respectively, by considering the maximum expected amounts of water in
combustion air, fuel combustion products, and dilution air
concentrations (if applicable).
    (c) Set x_H2Oexp equal to x_H2Omeas if you are
using a sample dryer that passes the sample dryer verification check in
Sec.  1065.342.
    (d) Calculate water quench as follows:

    [GRAPHIC] [TIFF OMITTED] TR06MY08.106
   
Where:

quench = amount of CLD quench.
x_NOdry = measured concentration of NO upstream of a
bubbler, according to Sec.  1065.370.
x_NOwet = measured concentration of NO downstream of a
bubbler, according to Sec.  1065.370.
x_H2Oexp = expected maximum amount of water entering the
CLD sample port during emission testing.
x_H2Omeas = measured amount of water entering the CLD
sample port during the quench verification specified in Sec.  1065.370.
x_NO,CO2 = measured concentration of NO when NO span gas
is blended with CO₂ span gas, according to Sec.  1065.370.
x_NO,N2 = measured concentration of NO when NO span gas is
blended with N₂ span gas, according to Sec.  1065.370.
x_CO2exp = expected maximum amount of CO₂
entering the CLD sample port during emission testing.
x_CO2meas = measured amount of CO₂ entering the
CLD sample port during the quench verification specified in Sec.  1065.370.

Example:

x_NOdry = 1800.0 &mu;mol/mol
x_NOwet = 1760.5 &mu;mol/mol
x_H2Oexp = 0.030 mol/mol
x_H2Omeas = 0.017 mol/mol
x_NO,CO2 = 1480.2 &mu;mol/mol
x_NO,N2 = 1500.8 &mu;mol/mol
x_CO2exp = 2.00%
x_CO2meas = 3.00%
[GRAPHIC] [TIFF OMITTED] TR06MY08.107

quench = -0.00888-0.00915 = -1.80%

• 123. Section 1065.690 is amended by revising paragraph (e) to read as
follows:

Sec.  1065.690  Buoyancy correction for PM sample media.

* * * * *
    (e) Correction calculation. Correct the PM sample media for
buoyancy using the following equations:
[GRAPHIC] [TIFF OMITTED] TR06MY08.108

Where:
m_cor = PM mass corrected for buoyancy.
m_uncor = PM mass uncorrected for buoyancy.
P_air = density of air in balance environment.
P_weight = density of calibration weight used to span
balance.
P_media = density of PM sample media, such as a filter.

[GRAPHIC] [TIFF OMITTED] TR06MY08.109

Where:
p_abs = absolute pressure in balance environment.
M_mix = molar mass of air in balance environment.
R = molar gas constant.
T_amb = absolute ambient temperature of balance
environment.

Example:
p_abs = 99.980 kPa
T_sat = T_dew = 9.5 [deg]C
Using Eq. 1065.645-2,
p_H20 = 1.1866 kPa
Using Eq. 1065.645-3,
x_H2O = 0.011868 mol/mol
Using Eq. 1065.640-9,
M_mix = 28.83563 g/mol
R = 8.314472 J/(mol [middot] K)
T_amb = 20 [deg]C
[GRAPHIC] [TIFF OMITTED] TR06MY08.110

[[Page 25342]]

P_air = 1.18282 kg/m3
m_uncorr = 100.0000 mg
P_weight = 8000 kg/m3
P_media = 920 kg/m3
[GRAPHIC] [TIFF OMITTED] TR06MY08.111

m_cor 100.1139 mg

• 124. Section 1065.695 is amended by revising paragraph (c)(7)(ix) to
read as follows:

Sec.  1065.695  Data requirements.

* * * * *
    (c) * * *
    (7) * * *
    (ix) Warm-idle speed value.
* * * * *

Subpart H--[Amended]

• 125. Section 1065.701 is amended by revising paragraphs (b), (c), and
(e) to read as follows:

Sec.  1065.701  General requirements for test fuels.

* * * * *
    (b) Fuels meeting alternate specifications. We may allow you to use
a different test fuel (such as California Phase 2 gasoline) if it does
not affect your ability to show that your engines would comply with all
applicable emission standards using the fuel specified in this subpart.
    (c) Fuels not specified in this subpart. If you produce engines
that run on a type of fuel (or mixture of fuels) that we do not specify
in this subpart, you must get our written approval to establish the
appropriate test fuel. See the standard-setting part for provisions
related to fuels and fuel mixtures not specified in this subpart.
    (1) For engines designed to operate on a single fuel, we will
generally allow you to use the fuel if you show us all the following
things are true:
    (i) Show that your engines will use only the designated fuel in service.
    (ii) Show that this type of fuel is commercially available.
    (iii) Show that operating the engines on the fuel we specify would
be inappropriate, as in the following examples:
    (A) The engine will not run on the specified fuel.
    (B) The engine or emission controls will not be durable or work
properly when operating with the specified fuel.
    (C) The measured emission results would otherwise be substantially
unrepresentative of in-use emissions.
    (2) For engines that are designed to operate on different fuel
types, the provisions of paragraphs (c)(1)(ii) and (iii) of this
section apply with respect to each fuel type.
    (3) For engines that are designed to operate on different fuel
types as well as continuous mixtures of those fuels, we may require you
to test with either the worst-case fuel mixture or the most representative
fuel mixture, unless the standard-setting part specifies otherwise.
* * * * *
    (e) Service accumulation and field testing fuels. If we do not
specify a service-accumulation or field-testing fuel in the standard-
setting part, use an appropriate commercially available fuel such as
those meeting minimum specifications from the following table:

              Table 1 of Sec.   1065.701.--Examples of Service-Accumulation and Field-Testing Fuels
----------------------------------------------------------------------------------------------------------------
             Fuel category                        Subcategory                    Reference procedure \1\
----------------------------------------------------------------------------------------------------------------
                                        Light distillate and light      ASTM D975-07b.
                                         blends with residual.
Diesel................................  Middle distillate.............  ASTM D6751-07b.
                                        Biodiesel (B100)..............  ASTM D6985-04a.
Intermediate and residual fuel........  All...........................  See Sec.   1065.705.
Gasoline..............................  Motor vehicle gasoline........  ASTM D4814-07a.
                                        Minor oxygenated gasoline       ASTM D4814-07a.
                                         blends.
Alcohol...............................  Ethanol (Ed75-85).............  ASTM D5798-07.
                                        Methanol (M70-M85)............  ASTM D5797-07.
Aviation fuel.........................  Aviation gasoline.............  ASTM D910-07.
                                        Gas turbine...................  ASTM D1655-07e01.
                                        Jet B wide cut................  ASTM D6615-06.
Gas turbine fuel......................  General.......................  ASTM D2880-03.
----------------------------------------------------------------------------------------------------------------
\1\ ASTM specifications are incorporated by reference in Sec.   1065.1010.

• 126. Section 1065.703 is amended by revising Table 1 to read as follows:

Sec.  1065.703  Distillate diesel fuel.

* * * * *

                Table 1 of Sec.   1065.703.--Test Fuel Specifications for Distillate Diesel Fuel
----------------------------------------------------------------------------------------------------------------
                                                       Ultra low                             Reference procedure
               Item                      Units           sulfur     Low sulfur  High sulfur          \1\
----------------------------------------------------------------------------------------------------------------
Cetane Number....................  .................        40-50        40-50        40-50  ASTM D613-05.
Distillation range...............  [deg]C...........                                         ...................
Initial boiling point............  .................      171-204      171-204      171-204  ASTM D86-07a.
10 pct. point....................  .................      204-238      204-238      204-238  ...................
50 pct. point....................  .................      243-282      243-282      243-282  ...................
90 pct. point....................  .................      293-332      293-332      293-332  ...................
Endpoint.........................  .................      321-366      321-366      321-366  ...................
Gravity..........................  [deg] API........        32-37        32-37        32-37  ASTM D4052-96e01.
Total sulfur.....................  mg/kg............         7-15      300-500    2000-4000  ASTM D2622-07.
Aromatics, min. (Remainder shall   g/kg.............          100          100          100  ASTM D5186-03.
 be paraffins, naphthalenes, and
 olefins).
Flashpoint, min..................  [deg]C...........           54           54           54  ASTM D93-07.

[[Page 25343]]


Kinematic Viscosity..............  cSt..............      2.0-3.2      2.0-3.2      2.0-3.2  ASTM D445-06.
----------------------------------------------------------------------------------------------------------------
\1\ ASTM procedures are incorporated by reference in Sec.   1065.1010. See Sec.   1065.701(d) for other allowed
  procedures.

• 127. A new Sec.  1065.705 is added to read as follows:

Sec.  1065.705  Residual and intermediate residual fuel.

    This section describes the specifications for fuels meeting the
definition of residual fuel in 40 CFR 80.2, including fuels marketed as
intermediate fuel. Residual fuels for service accumulation and any
testing must meet the following specifications:
    (a) The fuel must be a commercially available fuel that is
representative of the fuel that will be used by the engine in actual use.
    (b) The fuel must meet the specifications for one of the categories
in the following table:

                            Table 1 of Sec.   1065.705.--Service Accumulation and Test Fuel Specifications for Residual Fuel
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                                    Category ISO-F-
        Characteristic              Unit      ------------------------------------------------------------------------------------------   Test method
                                                RMA 30   RMB 30   RMD 80  RME 180  RMF 180  RMG 380  RMH 380  RMK 380  RMH 700  RMK 700   reference \1\
--------------------------------------------------------------------------------------------------------------------------------------------------------
Density at 15 [deg]C, max....  kg/m 3........    960.0    975.0    980.0        991.0
                                        991.0            1010.0    991.0   1010.0      ISO
                                                                                   3675 or
                                                                                       ISO
                                                                                    12185:
                                                                                     1996/
                                                                                       Cor
                                                                                    1:2001
                                                                                      (see
                                                                                      also
                                                                                       ISO
                                                                                   8217:20
                                                                                     05(E)
                                                                                     7.1).
--------------------------------------------------------------------------------------------------------------------------------------------------------
Kinematic viscosity at 50      cSt...........        30.0           80.0        180.0
 [deg]C, max.
                                        380.0
                                             700.0                   ISO
                                                                 3104:19
                                                                  94/Cor
                                                                 1:1997.
--------------------------------------------------------------------------------------------------------------------------------------------------------
Flash point, min.............  [deg]C........         60              60         60
                                          60
                                              60                     ISO
                                                                    2719
                                                                    (see
                                                                    also
                                                                     ISO
                                                                 8217:20
                                                                   05(E)
                                                                   7.2).
--------------------------------------------------------------------------------------------------------------------------------------------------------
Pour point (upper):
--------------------------------------------------------------------------------------------------------------------------------------------------------
    Winter quality, max......  [deg]C........        0       24       30         30
                                          30
                                              30                     ISO
                                                                   3016.
--------------------------------------------------------------------------------------------------------------------------------------------------------
    Summer quality, max......  ..............        6       24       30         30
                                          30
                                              30                     ISO
                                                                   3016.
--------------------------------------------------------------------------------------------------------------------------------------------------------
Carbon residue, max..........  (kg/kg)%......         10              14       15       20       18       22              22             ISO 10370:1993/
                                                                                                                                          Cor 1:1996.
--------------------------------------------------------------------------------------------------------------------------------------------------------
Ash, max.....................  (kg/kg)%......        0.10           0.10     0.10     0.15        0.15
                                             0.15                    ISO
                                                                   6245.
--------------------------------------------------------------------------------------------------------------------------------------------------------
Water, max...................  (m3/m3)%......         0.5            0.5         0.5
                                         0.5
                                              0.5                    ISO
                                                                   3733.
--------------------------------------------------------------------------------------------------------------------------------------------------------
Sulfur, max..................  (kg/kg)%......        3.50           4.00        4.50
                                         4.50
                                             4.50                    ISO
                                                                 8754 or
                                                                     ISO
                                                                  14596:
                                                                   1998/
                                                                     Cor
                                                                  1:1999
                                                                    (see
                                                                    also
                                                                     ISO
                                                                 8217:20
                                                                   05(E)
                                                                   7.3).
--------------------------------------------------------------------------------------------------------------------------------------------------------
Vanadium, max................  mg/kg.........         150            350      200      500      300      600             600             ISO 14597 or IP
                                                                                                                                          501 or IP 470
                                                                                                                                          (see also ISO
                                                                                                                                          8217:2005(E)
                                                                                                                                          7.8).
--------------------------------------------------------------------------------------------------------------------------------------------------------
Total sediment potential, max  (kg/kg)%......        0.10           0.10        0.10
                                         0.10
                                             0.10                    ISO
                                                                 10307-2
                                                                    (see
                                                                    also
                                                                     ISO
                                                                 8217:20
                                                                   05(E)
                                                                   7.6).
--------------------------------------------------------------------------------------------------------------------------------------------------------
Aluminium plus silicon, max..  mg/kg 80......         80              80         80
                                          80
                                              80                     ISO
                                                                   10478
                                                                   or IP
                                                                  501 or
                                                                  IP 470
                                                                    (see
                                                                    also
                                                                     ISO
                                                                 8217:20
                                                                   05(E)
                                                                   7.9).
--------------------------------------------------------------------------------------------------------------------------------------------------------
Used lubricating oil (ULO),    ..............    Fuel shall be free of ULO. We consider a fuel to be free of ULO if one or more of the   IP 501 or IP
 max.                                          elements zinc, phosphorus, or calcium is at or below the specified limits. We consider a   470 (see ISO
                                                        fuel to contain ULO if all three elements exceed the specified limits.            8217:2005(E)
                                                                                                                                          7.7).
                                                                                                                                         IP 501 or IP
                                                                                                                                          500 (see ISO
                                                                                                                                          8217:2005(E)
                                                                                                                                          7.7).
                                                                                                                                         IP 501 or IP
                                                                                                                                          470 (see ISO
                                                                                                                                          8217:2005(E)
                                                                                                                                          7.7).
                               mg/kg.........                                             15
Zinc.........................  ..............                                             15
Phosphorus...................  ..............                                             15
Calcium......................  ..............                                             30
--------------------------------------------------------------------------------------------------------------------------------------------------------
\1\ ISO procedures are incorporated by reference in Sec.   1065.1010. See Sec.   1065.701(d) for other allowed procedures.

• 128. Section 1065.710 is amended by revising Table 1 to read as follows:

Sec.  1065.710  Gasoline.

* * * * *

[[Page 25344]]

                        Table 1 of Sec.   1065.710.--Test Fuel Specifications for Gasoline
----------------------------------------------------------------------------------------------------------------
                                                                       Low-temperature     Reference  procedure
              Item                     Units        General testing        testing                 \1\
----------------------------------------------------------------------------------------------------------------
Distillation Range:
    Initial boiling point......  [deg]C..........  24-35 2..........  24-36............
    10% point..................  ................  49-57............  37-48............  ASTM D86-07a.
    50% point..................  ................  93-110...........  82-101...........
    90% point..................  ................  149-163..........  158-174..........
    End point..................  ................  Maximum, 213.....  Maximum, 212.....
Hydrocarbon composition:
    Olefins....................  m\3\/m\3\.......  Maximum, 0.10....  Maximum, 0.175...  ASTM D1319-03.
    Aromatics..................  ................  Maximum, 0.35....  Maximum, 0.304...
    Saturates..................  ................  Remainder........  Remainder........
Lead (organic).................  g/liter.........  Maximum, 0.013...  Maximum, 0.013...  ASTM D3237-06e01.
Phosphorous....................  g/liter.........  Maximum, 0.0013..  Maximum, 0.005...  ASTM D3231-07.
Total sulfur...................  mg/kg...........  Maximum, 80......  Maximum, 80......  ASTM D2622-07.
Volatility (Reid Vapor           kPa.............  60.0-63.4 \2\ \3\  77.2-81.4........  ASTM D5191-07.
 Pressure).
----------------------------------------------------------------------------------------------------------------
\1\ ASTM procedures are incorporated by reference in Sec.   1065.1010. See Sec.   1065.701(d) for other allowed
  procedures.
\2\ For testing at altitudes above 1,219 m, the specified volatility range is (52.0 to 55.2) kPa and the
  specified initial boiling point range is (23.9 to 40.6) [deg]C.
3 For testing unrelated to evaporative emissions, the specified range is (55.2 to 63.4) kPa.

• 129. Section 1065.715 is revised to read as follows:

Sec.  1065.715  Natural gas.

    (a) Except as specified in paragraph (b) of this section, natural
gas for testing must meet the specifications in the following table:

  Table 1 of Sec.   1065.715.--Test Fuel Specifications for Natural Gas
------------------------------------------------------------------------
                  Item                              Value \1\
------------------------------------------------------------------------
Methane, CH4...........................  Minimum, 0.87 mol/mol.
Ethane, C2H6...........................  Maximum, 0.055 mol/mol.
Propane, C3H8..........................  Maximum, 0.012 mol/mol.
Butane, C4H10..........................  Maximum, 0.0035 mol/mol.
Pentane, C5H12.........................  Maximum, 0.0013 mol/mol.
C6 and higher..........................  Maximum, 0.001 mol/mol.
Oxygen.................................  Maximum, 0.001 mol/mol.
Inert gases (sum of CO2 and N2)........  Maximum, 0.051 mol/mol.
------------------------------------------------------------------------
\1\ All parameters are based on the reference procedures in ASTM D1945-
  03 (incorporated by reference in Sec.   1065.1010). See Sec.
  1065.701(d) for other allowed procedures.

    (b) In certain cases you may use test fuel not meeting the
specifications in paragraph (a) of this section, as follows:
    (1) You may use fuel that your in-use engines normally use, such as
pipeline natural gas.
    (2) You may use fuel meeting alternate specifications if the
standard-setting part allows it.
    (3) You may ask for approval to use fuel that does not meet the
specifications in paragraph (a) of this section, but only if using the
fuel would not adversely affect your ability to demonstrate compliance
with the applicable standards.
    (c) When we conduct testing using natural gas, we will use fuel
that meets the specifications in paragraph (a) of this section.
    (d) At ambient conditions, natural gas must have a distinctive odor
detectable down to a concentration in air not more than one-fifth the
lower flammable limit.

• 130. Section 1065.720 is revised to read as follows:

Sec.  1065.720  Liquefied petroleum gas.

    (a) Except as specified in paragraph (b) of this section, liquefied
petroleum gas for testing must meet the specifications in the following
table:

   Table 1 of Sec.   1065.720.--Test Fuel Specifications for Liquefied
                              Petroleum Gas
------------------------------------------------------------------------
                                                           Reference
              Item                       Value           procedure \1\
------------------------------------------------------------------------
Propane, C3H8...................  Minimum, 0.85 m\3\/ ASTM D2163-05.
                                   m\3\.
Vapor pressure at 38 [deg]C.....  Maximum, 1400 kPa.  ASTM D1267-02 or
                                                       2598-02\2\.
Volatility residue (evaporated    Maximum, -38        ASTM D1837-02a.
 temperature, 35 [deg]C).          [deg]C.
Butanes.........................  Maximum, 0.05 m\3\/ ASTM D2163-05.
                                   m\3\.
Butenes.........................  Maximum, 0.02 m\3\/ ASTM D2163-05.
                                   m\3\.
Pentenes and heavier............  Maximum, 0.005      ASTM D2163-05.
                                   m\3\/m\3\.
Propene.........................  Maximum, 0.1 m\3\/  ASTM D2163-05.
                                   m\3\.
Residual matter (residue on       Maximum, 0.05 ml    ASTM D2158-05.
 evap. of 100 ml oil stain         pass\3\.
 observ.).
Corrosion, copper strip.........  Maximum, No. 1....  ASTM D1838-07.
Sulfur..........................  Maximum, 80 mg/kg.  ASTM D2784-06.

[[Page 25345]]

Moisture content................  pass..............  ASTM D2713-91.
------------------------------------------------------------------------
\1\ ASTM procedures are incorporated by reference in Sec.   1065.1010.
  See Sec.   1065.701(d) for other allowed procedures.
\2\ If these two test methods yield different results, use the results
  from ASTM D1267-02.
\3\ The test fuel must not yield a persistent oil ring when you add 0.3
  ml of solvent residue mixture to a filter paper in 0.1 ml increments
  and examine it in daylight after two minutes.

    (b) In certain cases you may use test fuel not meeting the
specifications in paragraph (a) of this section, as follows:
    (1) You may use fuel that your in-use engines normally use, such as
commercial-quality liquefied petroleum gas.
    (2) You may use fuel meeting alternate specifications if the
standard-setting part allows it.
    (3) You may ask for approval to use fuel that does not meet the
specifications in paragraph (a) of this section, but only if using the
fuel would not adversely affect your ability to demonstrate compliance
with the applicable standards.
    (c) When we conduct testing using liquefied petroleum gas, we will
use fuel that meets the specifications in paragraph (a) of this section.
    (d) At ambient conditions, liquefied petroleum gas must have a
distinctive odor detectable down to a concentration in air not more
than one-fifth the lower flammable limit.

• 131. Section 1065.750 is amended by revising paragraph (a) to read as
follows:

Sec.  1065.750  Analytical Gases.

* * * * *
    (a) Subparts C, D, F, and J of this part refer to the following gas
specifications:
    (1) Use purified gases to zero measurement instruments and to blend
with calibration gases. Use gases with contamination no higher than the
highest of the following values in the gas cylinder or at the outlet of
a zero-gas generator:
    (i) 2% contamination, measured relative to the flow-weighted mean
concentration expected at the standard. For example, if you would
expect a flow-weighted CO concentration of 100.0 &mu;mol/mol, then you
would be allowed to use a zero gas with CO contamination less than or
equal to 2.000 &mu;mol/mol.
    (ii) Contamination as specified in the following table:

                     Table 1 of Sec.   1065.750.--General Specifications for Purified Gases
----------------------------------------------------------------------------------------------------------------
           Constituent                   Purified synthetic air \1\                   Purified N2 \1\
----------------------------------------------------------------------------------------------------------------
THC (C1 equivalent)..............  < 0.05 &mu;mol/mol....................  < 0.05 &mu;mol/mol.
CO...............................  < 1 &mu;mol/mol.......................  < 1 &mu;mol/mol.
CO2..............................  < 10 &mu;mol/mol......................  < 10 &mu;mol/mol.
O2...............................  0.205 to 0.215 mol/mol................  < 2 &mu;mol/mol.
NOX..............................  < 0.02 &mu;mol/mol....................  < 0.02 &mu;mol/mol.
----------------------------------------------------------------------------------------------------------------
\1\ We do not require these levels of purity to be NIST-traceable.

    (2) Use the following gases with a FID analyzer:
    (i) FID fuel. Use FID fuel with a stated H\2\ concentration of
(0.39 to 0.41) mol/mol, balance He, and a stated total hydrocarbon
concentration of 0.05 &mu;mol/mol or less.
    (ii) FID burner air. Use FID burner air that meets the
specifications of purified air in paragraph (a)(1) of this section. For
field testing, you may use ambient air.
    (iii) FID zero gas. Zero flame-ionization detectors with purified
gas that meets the specifications in paragraph (a)(1) of this section,
except that the purified gas O₂ concentration may be any
value. Note that FID zero balance gases may be any combination of
purified air and purified nitrogen. We recommend FID analyzer zero
gases that contain approximately the expected flow-weighted mean
concentration of O₂ in the exhaust sample during testing.
    (iv) FID propane span gas. Span and calibrate THC FID with span
concentrations of propane, C₃H₈. Calibrate on a
carbon number basis of one (C₁). For example, if you use a
C₃H₈ span gas of concentration 200 &mu;mol/mol,
span a FID to respond with a value of 600 &mu;mol/mol. Note that FID
span balance gases may be any combination of purified air and purified
nitrogen. We recommend FID analyzer span gases that contain
approximately the flow-weighted mean concentration of O₂
expected during testing. If the expected O₂ concentration in
the exhaust sample is zero, we recommend using a balance gas of
purified nitrogen.
    (v) FID methane span gas. If you always span and calibrate a
CH₄ FID with a nonmethane cutter, then span and calibrate
the FID with span concentrations of methane, CH₄. Calibrate
on a carbon number basis of one (C₁). For example, if you
use a CH₄ span gas of concentration 200 &mu;mol/mol, span a
FID to respond with a value of 200 &mu;mol/mol. Note that FID span
balance gases may be any combination of purified air and purified
nitrogen. We recommend FID analyzer span gases that contain
approximately the expected flow-weighted mean concentration of
O₂ in the exhaust sample during testing. If the expected
O₂ concentration in the exhaust sample is zero, we recommend
using a balance gas of purified nitrogen.
    (3) Use the following gas mixtures, with gases traceable within
&plusmn; 1.0% of the NIST-accepted value or other gas standards we
approve:
    (i) CH₄, balance purified synthetic air and/or
N₂ (as applicable).
    (ii) C₂H₆, balance purified synthetic air
and/or N₂ (as applicable).
    (iii) C₃H₈, balance purified synthetic air
and/or N₂ (as applicable).
    (iv) CO, balance purified N₂.
    (v) CO₂, balance purified N₂.
    (vi) NO, balance purified N₂.
    (vii) NO₂, balance purified synthetic air.
    (viii) O₂, balance purified N₂.
    (ix) C₃H₈, CO, CO₂, NO, balance
purified N₂.
    (x) C₃H₈, CH₄, CO, CO₂,
NO, balance purified N₂.
    (4) You may use gases for species other than those listed in
paragraph (a)(3) of this section (such as methanol in air, which you
may use to determine response factors), as long as they are

[[Page 25346]]

traceable to within &plusmn; 3.0% of the NIST-accepted value or
other similar standards we approve, and meet the stability requirements
of paragraph (b) of this section.
    (5) You may generate your own calibration gases using a precision
blending device, such as a gas divider, to dilute gases with purified
N₂ or purified synthetic air. If your gas dividers meet the
specifications in Sec.  1065.248, and the gases being blended meet the
requirements of paragraphs (a)(1) and (3) of this section, the resulting
blends are considered to meet the requirements of this paragraph (a).
* * * * *

Subpart I--[Amended]

• 132. Section 1065.805 is amended by revising paragraphs (a), (b), and
(c) to read as follows:

Sec.  1065.805  Sampling system.

    (a) Dilute engine exhaust, and use batch sampling to collect
proportional flow-weighted dilute samples of the applicable alcohols
and carbonyls. You may not use raw sampling for alcohols and carbonyls.
    (b) You may collect background samples for correcting dilution air
for background concentrations of alcohols and carbonyls.
    (c) Maintain sample temperatures within the dilution tunnel,
probes, and sample lines high enough to prevent aqueous condensation up
to the point where a sample is collected to prevent loss of the
alcohols and carbonyls by dissolution in condensed water. Use good
engineering judgment to ensure that surface reactions of alcohols and
carbonyls do not occur, as surface decomposition of methanol has been
shown to occur at temperatures greater than 120 [deg]C in exhaust from
methanol-fueled engines.
* * * * *

• 133. Section 1065.845 is amended by revising the introductory text to
read as follows:

Sec.  1065.845  Response factor determination.

    Since FID analyzers generally have an incomplete response to
alcohols and carbonyls, determine each FID analyzer's alcohol/carbonyl
response factor (such as RF_MeOH) after FID optimization to
subtract those responses from the FID reading. You are not required to
determine the response factor for a compound unless you will subtract
its response to compensate for a response. Formaldehyde response is
assumed to be zero and does not need to be determined. Use the most
recent alcohol/carbonyl response factors to compensate for alcohol/
carbonyl response.
* * * * *

Subpart J--[Amended]

• 134. Section 1065.901 is amended by revising paragraphs (b)
introductory text and (b)(2) to read as follows:

Sec.  1065.901  Applicability.

* * * * *
    (b) Laboratory testing. You may use PEMS for any testing in a
laboratory or similar environment without restriction or prior approval
if the PEMS meets all applicable specifications for laboratory testing.
You may also use PEMS for any testing in a laboratory or similar
environment if we approve it in advance, subject to the following
provisions: * * *
    (2) Do not apply any PEMS-related field-testing adjustments or
measurement allowances to laboratory emission results or standards.
* * * * *

• 135. Section 1065.905 is amended by revising paragraphs (c)(14) and (e)
introductory text to read as follows:

Sec.  1065.905  General provisions.

* * * * *
    (c) * * *
    (14) Does any special measurement allowance apply to field-test
emission results or standards, based on using PEMS for field-testing
versus using laboratory equipment and instruments for laboratory
testing?
* * * * *
    (e) Laboratory testing using PEMS. You may use PEMS for testing in
a laboratory as described in Sec.  1065.901(b). Use the following
procedures and specifications when using PEMS for laboratory testing:
* * * * *

• 136. Section 1065.910 is revised to read as follows:

Sec.  1065.910  PEMS auxiliary equipment for field testing.

    For field testing you may use various types of auxiliary equipment
to attach PEMS to a vehicle or engine and to power PEMS.
    (a) When you use PEMS, you may route engine intake air or exhaust
through a flow meter. Route the engine intake air or exhaust as follows:
    (1) Flexible connections. Use short flexible connectors where necessary.
    (i) You may use flexible connectors to enlarge or reduce the pipe
diameters to match that of your test equipment.
    (ii) We recommend that you use flexible connectors that do not
exceed a length of three times their largest inside diameter.
    (iii) We recommend that you use four-ply silicone-fiberglass fabric
with a temperature rating of at least 315 [deg]C for flexible
connectors. You may use connectors with a spring-steel wire helix for
support and you may use NomexTM coverings or linings for
durability. You may also use any other nonreactive material with equivalent
permeation-resistance and durability, as long as it seals tightly.
    (iv) Use stainless-steel hose clamps to seal flexible connectors,
or use clamps that seal equivalently.
    (v) You may use additional flexible connectors to connect to flow
meters.
    (2) Tubing. Use rigid 300 series stainless steel tubing to connect
between flexible connectors. Tubing may be straight or bent to
accommodate vehicle geometry. You may use ``T'' or ``Y'' fittings made
of 300 series stainless steel tubing to join multiple connections, or
you may cap or plug redundant flow paths if the engine manufacturer
recommends it.
    (3) Flow restriction. Use flowmeters, connectors, and tubing that
do not increase flow restriction so much that it exceeds the
manufacturer's maximum specified value. You may verify this at the
maximum exhaust flow rate by measuring pressure at the manufacturer-
specified location with your system connected. You may also perform an
engineering analysis to verify an acceptable configuration, taking into
account the maximum exhaust flow rate expected, the field test system's
flexible connectors, and the tubing's characteristics for pressure
drops versus flow.
    (b) For vehicles or other motive equipment, we recommend installing
PEMS in the same location where a passenger might sit. Follow PEMS
manufacturer instructions for installing PEMS in cargo spaces, engine
spaces, or externally such that PEMS is directly exposed to the outside
environment. We recommend locating PEMS where it will be subject to
minimal sources of the following parameters:
    (1) Ambient temperature changes.
    (2) Ambient pressure changes.
    (3) Electromagnetic radiation.
    (4) Mechanical shock and vibration.
    (5) Ambient hydrocarbons--if using a FID analyzer that uses ambient
air as FID burner air.
    (c) Use mounting hardware as required for securing flexible
connectors, ambient sensors, and other equipment. Use structurally
sound mounting points such as vehicle frames, trailer hitch receivers,
walkspaces, and payload tie-down fittings. We

[[Continued on page 25347]]
Notices For
2008
2007
2006
2005
2004
2003
2002
2001
2000
1999
1998
1997
1996
1995
1994
Control of Emissions of Air Pollution From Locomotive Engines and Marine Compression-Ignition Engines Less Than 30 Liters per Cylinder

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