[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: 40CFR86.133-96]
[Page 518-520]
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. 86.133-96 Diurnal emission test.
(a)(1) The diurnal emission test for gasoline-, methanol- and
gaseous-fueled vehicles consists of three 24-hour test cycles following
the hot soak test. Emissions are measured for each 24-hour cycle, with
the highest emission level used to determine compliance with the
standards specified in subpart A of this part. The Administrator may
truncate a test after any 24-hour cycle without affecting the validity
of the collected data. Sampling of emissions from the running loss and
hot soak tests is not required as preparation for the diurnal emission
test. The diurnal emission test may be conducted as part of either the
three- diurnal test sequence or the supplemental two-diurnal test
sequence, as described in Sec. 86.130-96.
(2) For the full three-diurnal test sequence, the diurnal emission
test outlined in paragraphs (b) through (o) of this section follows the
high-temperature hot soak test concluded in Sec. 86.138-96(j).
(3) For the supplemental two-diurnal test sequence, the diurnal
emission test outlined in paragraph (p) of this section follows the
alternate hot soak test specified in Sec. 86.138-96(k). This test is
not required for gaseous-fueled vehicles.
(b) The test vehicle shall be soaked for not less than 6 hours nor
more than 36 hours between the end of the hot soak test and the start of
the diurnal emission test. For at least the last 6 hours of this period,
the vehicle shall be soaked at 72[deg]3 [deg]F.
The temperature tolerance may be waived for up to 10 minutes to allow
purging of the enclosure or transporting the vehicle into the enclosure
at the beginning of the diurnal emission test.
(c) The test vehicle shall be exposed to ambient temperatures cycled
according to the profile specified in Sec. 86.133 and appendix II of
this part.
(1) Temperatures measured with the underbody temperature sensor
shall
[[Page 519]]
follow the profile with a maximum deviation of 3 [deg]F at any time and
an average temperature deviation not to exceed 2 [deg]F, where the
average deviation is calculated using the absolute value of each
measured deviation. In addition, the temperature from the sidewall
temperature sensors shall follow the profile with a maximum deviation of
5 [deg]F at any time.
(2) Ambient temperatures shall be measured at least every minute.
Temperature cycling shall begin when time=0 minutes, as specified in
paragraph (i)(5) of this section.
(d) The diurnal enclosure shall be purged for several minutes prior
to the test. Warning: If at any time the concentration of hydrocarbons,
of methanol or of methanol and hydrocarbons exceeds 15,000 ppm C the
enclosure should be immediately purged. This concentration provides at
least a 4:1 safety factor against the lean flammability limit.
(e) The test vehicle, with the engine shut off and the test vehicle
windows and luggage compartment(s) opened, shall be moved into the
diurnal enclosure.
(f)-(g) [Reserved]
(h) Prior to sampling for emissions and throughout the period of
cycled ambient temperatures, the mixing fan(s) shall circulate the air
at a rate of 0.80.2 cfm per cubic foot of ambient
volume. The mixing fan(s), plus any additional fans if needed, shall
also maintain a minimum wind speed of 5 mph (8 km/hr) under the fuel
tank of the test vehicle. The Administrator may adjust fan speed and
location to ensure sufficient air circulation around the fuel tank. The
wind speed requirement may be satisfied by consistently using a fan
configuration that has been demonstrated to maintain a broad 5-mph air
flow in the vicinity of the vehicle's fuel tank, subject to verification
by the Administrator.
(i) Emission sampling may begin as follows:
(1) The FID (or HFID) hydrocarbon analyzer shall be zeroed and
spanned immediately prior to the sampling.
(2) Impingers charged with known volumes of pure deionized water
shall be placed in the methanol sampling system (methanol-fueled
vehicles only).
(3) Turn off purge blowers (if not already off).
(4) Close and seal enclosure doors (if not already closed and
sealed).
(5) Within 10 minutes of closing and sealing the doors, analyze
enclosure atmosphere for hydrocarbons and record. This is the initial
(time=0 minutes) hydrocarbon concentration, CHCi, required in
Sec. 86.143. Hydrocarbon emissions may be sampled continuously during
the test period.
(6) Analyze the enclosure atmosphere for methanol, if applicable,
and record. The methanol sampling must start simultaneously with the
initiation of the hydrocarbon analysis and continue for 4.00.5 minutes. This is the initial methanol concentration,
CCH3OHi, required in Sec. 86.143. Record the time
elapsed during this analysis. If the 4-minute sample period is
inadequate to collect a sample of sufficient concentration to allow
accurate GC analysis, rapidly collect the methanol sample in a bag and
then bubble the bag sample through the impingers at the specified flow
rate. The time elapsed between collection of the bag sample and flow
through the impingers should be minimized to prevent any losses. If the
test is conducted in a fixed-volume enclosure that allows airflow into
and out of the enclosure, the effect of makeup air dilution must be
factored into the analysis.
(j) If testing indicates that a vehicle design may result in fuel
temperature responses during enclosure testing that are not
representative of in-use summertime conditions, the Administrator may
adjust air circulation and temperature during the test as needed to
ensure that the test sufficiently duplicates the vehicle's in-use
experience.
(k) The FID (or HFID) hydrocarbon analyzer shall be zeroed and
spanned immediately prior to the end of each emission sampling period.
(l) Fresh impingers shall be installed in the methanol collection
system immediately prior to the end of each emission measurement, if
applicable.
(m) The end of the first, second, and third emission sampling period
shall occur 14406, 28806,
43206 minutes, respectively, after the beginning
of the
[[Page 520]]
initial sampling, as specified in paragraph (i)(5) of this section.
(1) At the end of each emission sampling period, analyze the
enclosure atmosphere for hydrocarbons and record. This is the final
hydrocarbon concentration, CHCf, required in Sec. 86.143.
The emission measurement at the end of each period becomes the initial
hydrocarbon concentration, CHCi, of the next emission
sampling period.
(2) Analyze the enclosure atmosphere for methanol, if applicable,
and record. The methanol sampling must start simultaneously with the
initiation of the hydrocarbon analysis and continue for 4.00.5 minutes. This is the final (time=1440 minutes)
methanol concentration, CCH3OHf, required in Sec.
86.143. Record the time elapsed during this analysis. If the 4-minute
sample period is inadequate to collect a sample of sufficient
concentration to allow accurate GC analysis, rapidly collect the
methanol sample in a bag and then bubble the bag sample through the
impingers at the specified flow rate. The time elapsed between
collection of the bag sample and flow through the impingers should be
minimized to prevent any losses. If the test is conducted in a fixed-
volume enclosure that allows airflow into and out of the enclosure, the
effect of makeup air dilution must be factored into the analysis.
(n) At the end of the temperature cycling period the enclosure doors
shall be unsealed and opened, the test vehicle windows and luggage
compartments may be closed and the test vehicle, with the engine shut
off, shall be removed from the enclosure.
(o) This completes the full three-diurnal evaporative emission test
sequence described in Sec. 86.130-96.
(p) For the supplemental two-diurnal test sequence described in
Sec. 86.130-96, the following steps shall be performed in lieu of the
steps described in paragraphs (b) through (n) of this section.
(1) For the supplemental two-diurnal test sequence, the test vehicle
shall be soaked for not less than 6 hours nor more than 36 hours between
the end of the hot soak test described in Sec. 86.138-96(k), and the
start of the two-diurnal emission test. For at least the last 6 hours of
this period, the vehicle shall be soaked at 723
[deg]F.
(2) The vehicle shall be tested for diurnal emissions according to
the procedures specified in paragraphs (c) through (n) of this section,
except that the test includes only two 24-hour periods. Therefore the
end of the first and second emission sampling periods shall occur
14406 and 28806 minutes,
respectively, after the initial sampling.
(3) This completes the supplemental two-diurnal test sequence for
evaporative emission measurement.
[58 FR 16039, Mar. 24, 1993, as amended at 59 FR 48509, Sept. 21, 1994;
60 FR 43896, Aug. 23, 1995]