Section 86.137-94 - Dynamometer test run, gaseous and particulate emissionsSection 86.137-94 includes text that specifies requirements that differ from § 86.137-90 . Where a paragraph in § 86.137-90 is identical and applicable to § 86.137-94 , this may be indicated by specifying the corresponding paragraph and the statement "[Reserved]. For guidance see § 86.137-90 ." Where a corresponding paragraph of § 86.137-90 is not applicable, this is indicated by the statement "[Reserved]."
(a)General. The dynamometer run consists of two tests, a cold start test, after a minimum 12-hour and a maximum 36-hour soak according to the provisions of § 86.132 , and a hot start test following the cold start test by 10 minutes. The vehicle shall be stored prior to the emission test in such a manner that precipitation (e.g., rain or dew) does not occur on the vehicle. The complete dynamometer test consists of a cold start drive of 7.5 miles (12.1 km) and simulates a hot start drive of 7.5 miles (12.1 km). The vehicle is allowed to stand on the dynamometer during the 10 minute time period between the cold and hot start tests. The cold start test is divided into two periods. The first period, representing the cold start "transient" phase, terminates at the end of the deceleration which is scheduled to occur at 505 seconds of the driving schedule. The second period, representing the "stabilized" phase, consists of the remainder of the driving schedule including engine shutdown. The hot start test, similarly, consists of two periods. The first period, representing the hot start "transient" phase, terminates at the same point in driving schedule as the first period of the cold start test. The second period of the hot start test, "stabilized" phase, is assumed to be identical to the second period of the cold start test. Therefore, the hot start test terminates after the first period (505 seconds) is run.(b) The following steps shall be taken for each test:(1) Place drive wheels of vehicle on dynamometer without starting engine.(2) Open the vehicle engine compartment cover and position the cooling fan.(3) For all vehicles, with the sample selector valves in the "standby" position, connect evacuated sample collection bags to the dilute exhaust and dilution air sample collection systems.(4) For methanol-fueled vehicles, with the sample selector valves in the "standby" position, insert fresh sample collection impingers into the methanol sample collection system, fresh impingers or a fresh cartridge into the formaldehyde sample collection system and fresh impingers (or a single cartridge for formaldehyde) into the dilution air sample collection systems for methanol and formaldehyde (background measurements of methanol and formaldehyde may be omitted and concentrations assumed to be zero for calculations in § 86.144 ).(5) Start the CVS (if not already on), the sample pumps (except the particulate sample pump, if applicable), the temperature recorder, the vehicle cooling fan, and the heated THC analysis recorder (diesel-cycle only). (The heat exchanger of the constant volume sampler, if used, petroleum-fueled diesel-cycle THC analyzer continuous sample line and filter, methanol-fueled vehicle THC, methanol and formaldehyde sample lines, if applicable, should be preheated to their respective operating temperatures before the test begins).(6) Adjust the sample flow rates to the desired flow rate and set the gas flow measuring devices to zero. (i) For gaseous bag samples (except THC samples), the minimum flow rate is 0.17 cfm (0.08 1/sec).(ii) For THC samples, the minimum FID (or HFID in the case of diesel-cycle and methanol-fueled Otto-cycle vehicles) flow rate is 0.066 cfm (0.031 1/sec).(iii) For methanol samples, the flow rates shall be set such that the system meets the design criteria of § 86.109 and § 86.110 . For samples in which the concentration in the primary impinger exceeds 0.5 mg/l, it is recommended that the mass of methanol collected in the secondary impinger not exceed ten percent of the total mass collected. For samples in which the concentration in the primary impinger does not exceed 0.5 mg/l, analysis of the secondary impingers is not necessary.(iv) For formaldehyde samples, the flow rates shall be set such that the system meets the design criteria of § 86.109 and § 86.110 . For impinger samples in which the concentration of formaldehyde in the primary impinger exceeds 0.1 mg/l, it is recommended that the mass of formaldehyde collected in the secondary impinger not exceed ten percent of the total mass collected. For samples in which the concentration in the primary impinger does not exceed 0.1 mg/l, analysis of the secondary impingers is not necessary.(7) Attach the exhaust tube to the vehicle tailpipe(s).(8) Carefully install a particulate sample filter into each of the filter holders. The filters must be handled only with forceps or tongs. Rough or abrasive filter handling will result in erroneous weight determination.(9) Start the gas flow measuring device, position the sample selector valves to direct the sample flow into the "transient" exhaust sample bag, the "transient" methanol exhaust sample, the "transient" formaldehyde exhaust sample, the "transient" dilution air sample bag, the "transient" methanol dilution air sample and the "transient" formaldehyde dilution air sample (turn on the petroleum-fueled diesel-cycle THC analyzer system integrator, mark the recorder chart, start particulate sample pump No. 1, and record both gas meter or flow measurement instrument readings, if applicable), turn the key on, and start cranking the engine.(10) Fifteen seconds after the engine starts, place the transmission in gear.(11) Twenty seconds after the engine starts, begin the initial vehicle acceleration of the driving schedule.(12) Operate the vehicle according to the Urban Dynamometer Driving Schedule (§ 86.115 ). Note: During particulate testing, adjust the flow rate through the particulate sample probe to maintain a constant value within ±5 percent of the set flow rate. Record the average temperature and pressure at the gas meter or flow instrument inlet. If the set flow rate cannot be maintained because of high particulate loading on the filter, the test shall be terminated. The test shall be rerun using a lower flow rate, or larger diameter filter, or both.
(13) At the end of the deceleration which is scheduled to occur at 505 seconds, simultaneously switch the sample flows from the "transient" bags and samples to the "stabilized" bags and samples, switch off gas flow measuring device No. 1, switch off the No. 1 petroleum-fueled diesel hydrocarbon integrator and the No. 1 particulate sample pump, mark the petroleum-fueled diesel hydrocarbon recorder chart, and close valves isolating particulate filter No. 1, if applicable, start gas flow measuring device No. 2, and start the petroleum-fueled diesel hydrocarbon integrator No. 2 and the No. 2 particulate sample pump and open valves isolating particulate filter No. 2, if applicable. Before the acceleration which is scheduled to occur at 510 seconds, record the measured roll or shaft revolutions and reset the counter or switch to a second counter. As soon as possible transfer the "transient" exhaust and dilution air samples to the analytical system and process the samples according to § 86.140 obtaining a stabilized reading of the bag exhaust sample on all analyzers within 20 minutes of the end of the sample collection phase of the test. Obtain methanol and formaldehyde sample analyses, if applicable, within 24 hours of the end of the sample collection phase of the test.(14) Turn the engine off 2 seconds after the end of the last deceleration (at 1,369 seconds).(15) Five seconds after the engine stops running, simultaneously turn off gas flow measuring device No. 2 and if applicable, turn off the hydrocarbon integrator No. 2, mark the hydrocarbon recorder chart, turn off the No. 2 particulate sample pump and close the valves isolating particulate filter No. 2, and position the sample selector valves to the "standby" position (and open the valves isolating particulate filter No. 1, if applicable). Record the measured roll or shaft revolutions (both gas meter or flow measurement instrumentation readings), and reset the counter. As soon as possible, transfer the "stabilized" exhaust and dilution air samples to the analytical system and process the samples according to § 86.140 , obtaining a stabilized reading of the exhaust bag sample on all analyzers within 20 minutes of the end of the sample collection phase of the test. Obtain methanol and formaldehyde sample analyses, if applicable, within 24 hours of the end of the sample period. (If it is not possible to perform analysis on the methanol and formaldehyde samples within 24 hours, the samples should be stored in a dark cold (4-10 °C) environment until analysis. The samples should be analyzed within fourteen days.) If applicable, carefully remove both pairs of particulate sample filters from their respective holders, and place each in a separate petri dish, and cover.(16) Immediately after the end of the sample period, turn off the cooling fan and close the engine compartment cover.(17) Turn off the CVS or disconnect the exhaust tube from the tailpipe(s) of the vehicle.(18) Repeat the steps in paragraphs (b)(2) through (b)(12) of this section for the hot start test, except only two evacuated sample bags, two methanol sample impingers, two formaldehyde sample impingers, and one pair of particulate sample filters, as appropriate, are required. The step in paragraph (b)(9) of this section shall begin between 9 and 11 minutes after the end of the sample period for the cold-start test.(19) At the end of the deceleration scheduled to occur at 505 seconds, simultaneously turn off gas flow measuring device No. 1 (and the petroleum-fueled diesel hydrocarbon integrator No. 1; mark the petroleum-fueled diesel hydrocarbon recorder chart and turn off the No. 1 particulate sample pump, if applicable) and position the sample selector valve to the "standby" position. (Engine shutdown is not part of the hot start test sample period.) Record the measured roll or shaft revolutions (and the No. 1 gas meter reading or flow measurement instrument). Carefully remove the third pair of particulate sample filters from the holder and place in a clean petri dish and cover, if applicable.(20) As soon as possible, transfer the hot start "transient" exhaust and dilution air samples to the analytical system and process the samples according to § 86.140 , obtaining a stabilized reading of the exhaust bag sample on all analyzers within 20 minutes of the end of the sample collection phase of the test. Obtain methanol and formaldehyde sample analyses, if applicable, within 24 hours of the end of the sample period. If it is not possible to perform analysis on the methanol and formaldehyde samples within 24 hours, the samples should be stored in a dark, cold (4-10 °C) environment until analysis. Analyze the samples within fourteen days.(21) As soon as possible, and in no case longer than one hour after the end of the hot start phase of the test, transfer the six particulate filters to the weighing chamber for post-test conditioning, if applicable.(22) Disconnect the exhaust tube from the vehicle tailpipe(s) and drive the vehicle from dynamometer.(23) The CVS or CFV may be turned off, if desired.(24) This completes the test sequence for vehicles that do not need testing for evaporative emissions. Continue testing for evaporative emissions as follows: (i) For the three-day diurnal test sequence, proceed according to § 86.134 .(ii) For the two-day diurnal test sequence, proceed according to § 86.138-96(k) . The following additional provisions apply for heavy-duty vehicles: (A) For vehicles with a nominal fuel tank capacity at or above 50 gallons, operate the vehicle over a second full FTP cycle before measuring evaporative emissions; exhaust emission measurement is not required for the additional FTP cycle.56 FR 25776, June 5, 1991, as amended at 60 FR 34347, June 30, 1995; 79 FR 23697 , Apr. 28, 2014; 88 FR 4475 , Jan. 24, 2023