[Code of Federal Regulations]
[Title 40, Volume 17]
[Revised as of July 1, 2004]
From the U.S. Government Printing Office via GPO Access
[CITE: 40CFR86.110-90]
[Page 433-440]
TITLE 40--PROTECTION OF ENVIRONMENT
CHAPTER I--ENVIRONMENTAL PROTECTION AGENCY (CONTINUED)
PART 86_CONTROL OF EMISSIONS FROM NEW AND IN-USE HIGHWAY VEHICLES AND
ENGINES--Table of Contents
Subpart B_Emission Regulations for 1977 and Later Model Year New Light-
Sec. 86.110-90 Exhaust gas sampling system; diesel vehicles.
(a) General. The exhaust gas sampling system described in this
paragraph is designed to measure the true mass of both gaseous and
particulate emissions in the exhaust of either diesel light-duty
vehicles and light-duty trucks. This system utilizes the CVS concept
(described in Sec. 86.109) of measuring mass emissions. The mass of
gaseous emissions is determined from the sample concentration and total
flow over the test period. The mass of particulate emissions is
determined from a proportional mass sample collected on a filter and
from the total flow over the test period. General requirements are as
follows:
(1) This sampling system requires the use of a PDP-CVS or a CFV
sample system with heat exchanger connected to a dilution tunnel. Figure
B90-5 is a schematic drawing of the PDP system. Figure B90-6 is a
schematic drawing of the CFV system (methanol-fueled Otto-cycle vehicles
may be tested using this test equipment.)
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[GRAPHIC] [TIFF OMITTED] TR06OC93.149
[[Page 435]]
[GRAPHIC] [TIFF OMITTED] TR06OC93.150
(2) Bag, HFID, and particulate sampling capabilities as shown in
Figure B90-5 (or Figure B90-6) are required to provide both gaseous and
particulate emissions sampling capabilities from a single system.
[[Page 436]]
(3) Petroleum-fueled diesel vehicles require a heated flame
ionization detector (HFID) (375[deg]20 [deg]F
(191[deg]11 [deg]C)) sample for hydrocarbon
analysis. The HFID sample must be taken directly from the diluted
exhaust stream through a heated probe in the dilution tunnel.
(4) Methanol-fueled vehicles require the use of a heated flame
ionization detector (HFID) (235[deg]15 [deg]F
(113[deg]8 [deg]C)) for hydrocarbon analysis. With
an HFID, the hydrocarbon analysis can be made on the bag sample and the
methanol and formaldehyde analyses are performed on the samples
collected for these purposes (Figures B90-2 and B90-3). NOTE: For 1990
through 1994 model year methanol-fueled vehicles, methanol and
formaldehyde sampling may be omitted provided the bag sample is analyzed
using a HFID calibrated with methanol.
(5) Methanol-fueled vehicles require either:
(i) A tailpipe to dilution tunnel duct of unrestricted length
maintained at 235[deg]15 [deg]F (113[deg]8 [deg]C) through heating and cooling as required; or
(ii) Using short duct (up to 12 feet long) constructed of smooth
wall pipe with a minimum of flexible sections maintained at
235[deg]15 [deg]F (113[deg]
[deg]C) prior to the test and during breaks in testing (insulation may
remain in place and/or heating may occur during testing provided maximum
temperature is not exceeded); or
(iii) Using a smooth wall duct less than five feet long with no
required heating, or
(iv) Omitting the duct and performing the exhaust gas dilution
function at the vehicle tailpipe exit.
(6) Since various con fig u ra tions can produce equivalent results,
exact conformance with these drawings is not required. Additional
components such as instruments, valves, solenoids, pumps, and switches
may be used to provide additional information and coordinate the
functions of the component systems.
(7) Other sampling systems may be used if shown to yield equivalent
results and if approved in advance by the Administrator.
(b) Component description--petroleum-fueled diesel vehicles. The
components necessary for petroleum fueled diesel vehicle exhaust
sampling shall meet the following requirements:
(1) The PDP-CVS, Figure B90-5, shall conform to all of the
requirements listed for the exhaust gas PDP-CVS (Sec. 86.109(b)), with
one exception: a flow rate of sufficient volume is required to maintain
the diluted exhaust stream, from which the particulate sample flow is
taken, at a temperature of 125 [deg]F (52 [deg]C) or less.
(2) The CFV sample system, Figure B90-6, shall conform to all of the
requirements listed for the exhaust gas CFV sample system (Sec.
86.109(c)), with four exceptions:
(i) A flow rate of sufficient volume is required to maintain the
diluted exhaust stream, from which the particulate sample flow is taken,
at a temperature of 125 [deg]F (52 [deg]C) or less.
(ii) A heat exchanger is required.
(iii) The gas mixture temperature, measured at a point immediately
ahead of the critical flow venturi, shall be within 20 [deg]F (11 [deg]C) of the designed operating
temperature at the start of the test. The gas mixture temperature
variation from its value at the start of the test shall be limited to
20 [deg]F (11 [deg]C) during the entire test. The
temperature measuring system shall have an accuracy and precision of
2 [deg]F (1.1 [deg]C).
(iv) The cyclonic separator is optional.
(3) The transfer of heat from the vehicle exhaust gas shall be
minimized between the point where it leaves the vehicle tailpipe(s) and
the point where it enters the dilution tunnel airstream. To accomplish
this, a short length (not more than 12 feet (365 cm) if uninsulated, or
not more than 20 feet (610 cm) if insulated) of smooth stainless steel
tubing from the tailpipe to the dilution tunnel is required. This tubing
shall have a maximum inside diameter of 4.0 inches (10.2 cm). Short
sections of flexible tubing at connection points are allowed.
(4) The vehicle exhaust shall be directed downstream at the point
where it is introduced into the dilution tunnel.
(5) The dilution air shall be between 68 [deg]F (20 [deg]C) and 86
[deg]F (30 [deg]C) during the test.
[[Page 437]]
(6) The dilution tunnel shall be:
(i) Sized to permit development of turbulent flow (Reynold's No.
4000) and complete mixing of the exhaust and
dilution air between the mixing orifice and each of the two sample
probes (i.e., the particulate probe and the heated HC sample probe). It
is recommended that uniform mixing be demonstrated by the user.
(ii) At least 8.0 inches (20.3 cm) in diameter.
(iii) Constructed of electrically conductive material which does not
react with the exhaust components.
(iv) Grounded.
(7) The temperature of the diluted exhaust stream inside of the
dilution tunnel shall be sufficient to prevent water condensation.
However, the sample zone dilute exhaust temperature shall not exceed 125
[deg]F (52 [deg]C) at any time during the test.
(8) The particulate sample probe shall be:
(i) Installed facing upstream at a point where the dilution air and
exhaust are well mixed (i.e., near the tunnel centerline, approximately
10 tunnel diameters downstream from the point where the exhaust enters
the dilution tunnel).
(ii) Sufficiently distant (radially) from the total hydrocarbon
probe so as to be free from the influence of any wakes or eddies
produced by the total hydrocarbon probe.
(iii) 0.5 inch (1.27 cm) minimum inside diameter.
(iv) The distance from the sampling tip to the filter holder shall
be at least 5 probe diameters (for filters located inside of the
tunnel), but not more than 40.0 inches (102 cm) for filters located
outside of the dilution tunnel.
(v) Free from sharp bends.
(vi) Configured so that a clean particulate filter (including back-
up filter) can be selected simultaneously with the selection of an empty
gaseous emissions bag.
(9) The flow rate through the particulate probe shall be maintained
to a constant value within 5 percent of the set
flow rate.
(10) The particulate sample pump shall be located sufficiently
distant from the dilution tunnel so that the inlet gas temperature is
maintained at a constant temperature (5.0 [deg]F
(2.8 [deg]C)).
(11) The gas meters or flow instrumentation shall be located
sufficiently distant from the tunnel so that the inlet gas temperature
remains constant (5.0 [deg]F (2.8 [deg]C)).
(12) The total hydrocarbon probe shall be:
(i) Installed facing upstream at a point where the dilution air and
exhaust are well mixed (i.e., approximately 10 tunnel diameters
downstream from the point where the exhaust enters the dilution tunnel).
(ii) Sufficiently distant (radially) from the particulate probe so
as to be free from the influence of any wakes or eddies produced by the
particulate probe.
(iii) Heated and insulated over the entire length to maintain a
375[deg]20 [deg]F (191[deg]11 [deg]C) wall temperature.
(iv) 0.19 in. (0.48 cm) minimum inside diameter.
(13) It is intended that the total hydrocarbon probe be free from
cold spots (i.e., free from spots where the probe wall temperature is
less than 355 [deg]F). This will be determined by a temperature sensor
located on a section of the probe wall outside of the dilution tunnel.
The temperature sensor shall be insulated from any heating elements on
the probe. The sensor shall have an accuracy and precision of 2 [deg]F (1.1 [deg]C).
(14) The dilute exhaust gas flowing in the total hydrocarbon sample
system shall be:
(i) At 375 [deg]F10 [deg]F (191 [deg]C6 [deg]C) immediately before the heated filter. This
will be determined by a temperature sensor located immediately upstream
of the filter. The sensor shall have an accuracy and precision of 2 [deg]F (1.1 [deg]C).
(ii) At 375 [deg]F10 [deg]F (191 [deg]C6 [deg]C) immediately before the HFID. This will be
determined by a temperature sensor located at the exit of the heated
sample line. The sensor shall have an accuracy and precision of 2 [deg]F (1.1 [deg]C).
(15) It is intended that the dilute exhaust gas flowing in the total
hydrocarbon sample system be between 365 [deg]F and 385 [deg]F (185
[deg]C and 197 [deg]C).
(c) Component description--methanol-fueled diesel vehicles. The
components necessary for methanol-fueled diesel
[[Page 438]]
vehicle exhaust sampling shall meet the following requirements:
(1) The PDP-CVS, Figure B90-5 shall conform to all of the
requirements listed for the exhaust gas PDP-CVS (Sec. 86.109 (a)(3) and
(b)), with one exception: a flow rate of sufficient volume is required
to maintain the diluted exhaust stream, from which the particulate
sample flow is taken, at a temperature of 125 [deg]F (52 [deg]C) or less
and shall prevent the condensation of water vapor in the dilution
tunnel.
(2) The CFV sample system, Figure B90-6 shall conform to all of the
requirements listed for the exhaust gas CFV sample system (Sec. 86.109
(a)(4) and (c)), with four exceptions:
(i) A flow rate of sufficient volume is required to maintain the
diluted exhaust stream, from which the particulate sample flow is taken,
at a temperature of 125 [deg]F (52 [deg]C) or less and shall prevent the
condensation of water vapor in the dilution tunnel.
(ii) A heat exchanger is required.
(iii) The gas mixture temperature, measured at a point immediately
ahead of the critical flow venturi, shall be within 20 [deg]F (11 [deg]C) of the designed operating
temperature at the start of the test. The gas mixture temperature
variation from its value at the start of the test shall be limited to
20 [deg]F (11 [deg]C) during the entire test. The
temperature measuring system shall have an accuracy and precision of
2 [deg]F (1.1 [deg]C).
(iv) The cyclonic separator is optional.
(3) Losses of methanol due to condensation of water in the duct
connecting the vehicle tail pipe to the dilation tunnel must be
minimized. This may be accomplished by:
(i) The use of a duct of unrestricted length maintained at
235[deg]15 [deg]F (113[deg]8
[deg]C) through heating and cooling as required, or
(ii) The use of a short duct (up to 12 feet long) constructed of
smooth wall pipe with a minimum of flexible sections maintained at
235[deg]15 [deg]F (113[deg]8
[deg]C) prior to the test and during breaks in testing (insulation may
remain in place and/or heating may occur during testing provided maximum
temperature is not exceeded); or
(iii) Using a smooth wall duct less than five feet long with no
required heating, or
(iv) Omitting the duct and performing the exhaust gas dilution
function at the vehicle tailpipe exit.
(4) The vehicle exhaust shall be directed downstream at the point
where it is introduced into the dilution tunnel.
(5) The dilution air shall be between 68 [deg]F (20 [deg]C) and 86
[deg]F (30 [deg]C) during the test.
(6) The dilution tunnel shall be:
(i) Sized to permit development of turbulent flow (Reynold's No.
4000) and complete mixing of the exhaust and
dilution air between the mixing orifice and the particulate sample
probe. It is recommended that uniform mixing be demonstrated by the
user.
(ii) At least 8.0 inches (20.3 cm) in diameter.
(iii) Constructed of electrically conductive material which does not
react with the exhaust components.
(iv) Grounded.
(7) The temperature of the diluted exhaust stream inside of the
dilution tunnel shall be sufficient to prevent water condensation.
However, the sample zone dilute exhaust temperature shall not exceed 125
[deg]F (52 [deg]C) at any time during the test.
(8) The particulate sample probe shall be:
(i) Installed facing upstream at a point where the dilution air and
exhaust are well mixed (i.e., near the tunnel centerline, approximately
10 tunnel diameters downstream from the point where the exhaust enters
the dilution tunnel).
(ii) Sufficiently distant (radially) from the total hydrocarbon
probe so as to be free from the influence of any wakes or eddies
produced by the total hydrocarbon probe.
(iii) 0.5 inch (1.27 cm) minimum inside diameter.
(iv) The distance from the sampling tip to the filter holder shall
be at least 5 probe diameters (for filters located inside of the
tunnel), but not more than 40.0 inches (102 cm) for filters located
outside of the dilution tunnel.
(v) Free from sharp bends.
(vi) Configured so that a clean particulate filter (including back
up filter)
[[Page 439]]
can be selected simultaneously with the selection of an empty gaseous
emissions bag.
(9) The flow rate through the particulate probe shall be maintained
to a constant value within 5 percent of the set
flow rate.
(10) The particulate sample pump shall be located sufficiently
distant from the dilution tunnel so that the inlet gas temperature is
maintained at a constant temperature (5.0 [deg]F
(2.8 [deg]C)).
(11) The gas meters or flow instrumentation shall be located
sufficiently distant from the tunnel so that the inlet gas temperature
remains constant (5.0 [deg]F (2.8 [deg]C)).
(12) The hydrocarbon probe shall be:
(i) Installed facing upstream at a point where the dilution air and
exhaust are well mixed (i.e., approximately 10 tunnel diameters
downstream from the point where the exhaust enters the dilution tunnel).
(ii) Sufficiently distant (radially) from the particulate probe so
as to be free from the influence of any wakes or eddies produced by the
particulate probe.
(iii) Heated and insulated over the entire length to maintain a
235[deg]15 [deg]F (113[deg]8
[deg]C) wall temperature.
(iv) 0.19in. (0.48 cm) minimum inside diameter.
(13) It is intended that the total hydrocarbon probe be free from
cold spots (i.e., free from cold spots where the probe wall temperature
is less than 220 [deg]F.) This will be determined by a temperature
sensor located on a section of the probe wall outside of the dilution
tunnel. The temperature sensor shall be insulated from any heating
elements on the probe. The sensor shall have an accuracy and precision
of 2 [deg]F (1.1 [deg]C).
(14) The dilute exhaust gas flowing in the hydrocarbon sample system
shall be:
(i) At 235 [deg]F15 [deg]F (113 [deg]C8 [deg]C) immediately before the heated filter. This
will be determined by a temperature sensor located immediately upstream
of the filter. The sensor shall have an accuracy and precision of 2 [deg]F (1.1 [deg]C).
(ii) At 235 [deg]F15 [deg]F (113 [deg]C 8 [deg]C) immediately before the HFID. This will be
determined by a temperature sensor located at the exit of the heated
sample line. The sensor shall have an accuracy and precision of 2 [deg]F (1.1 [deg]C).
(15) It is intended that the dilute exhaust gas flowing in the
hydrocarbon sample system be between 220 [deg]F and 250 [deg]F (105
[deg]C and 121 [deg]C).
(16) For methanol-fueled vehicles, bag sampling procedures for the
measurement of hydrocarbons as described in Sec. 86.109 may be
employed.
(d) Filters, particulate sampling. (1) Filter acceptance criteria.
Valid diesel particulate net filter weights shall be accepted according
to the following criteria:
(i) During each phase of the UDDS, dilute exhaust will be
simultaneously sampled by paired primary test and back-up test filters.
(ii) The back-up filter holder shall be located 3 to 4 inches
downstream of the primary filter holder.
(iii) The net weight of particulate material collected on each
primary test filter and each back-up test filter shall be determined by
the procedure outlined in Sec. 86.139.
(iv) A ratio of net weights will be determined by the following
formula:
[GRAPHIC] [TIFF OMITTED] TR06OC93.013
(v) If the ratio is greater than 0.95, then particulate emissions
calculations are based on the net weight of the primary filter only.
(vi) If the ratio is less than 0.95, then particulate emissions
calculations are based on the combined net weights of the back-up test
filter and the primary test filter.
(2) The particulate filter must have a minimum 47 mm diameter (37 mm
stain area). Larger diameter filters are
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also acceptable. (Larger diameter filters may be desirable in order to
reduce the pressure drop across the filter when testing vehicles which
produce large amounts of particulate.)
(3) The recommended minimum loading on the primary 47 mm filter is
0.5 milligrams. Equivalent loadings (i.e., mass/stain area) are
recommended for larger filters.
(4) Fluorocarbon coated glass fiber filters or fluorocarbon-based
(membrane) filters are required for particulate collection.
[54 FR 14507, Apr. 11, 1989]