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Code of Federal Regulations (Last Updated: November 8, 2024) |
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Title 40 - Protection of Environment |
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Chapter I - Environmental Protection Agency |
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SubChapter C - Air Programs |
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Part 86 - Control of Emissions from New and in-Use Highway Vehicles and Engines |
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Subpart N - Exhaust Test Procedures for Heavy-duty Engines |
§ 86.1343-88 - Calculations; particulate exhaust emissions.
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Link to an amendment published at 79 FR 23704, Apr. 28, 2014.
(a) The final reported transient emission test results shall be computed by use of the following formula:
(1) Pwm = Weighted mass particulate, grams per brake horsepower-hour.
(2) PC = Mass particulate measured during the cold-start test, grams.
(3) PH = Mass particulate measured during the hot-start test, grams.
(4) BHP-hrC = Total brake horsepower-hour (brake horsepower integrated with respect to time) for the cold-start test.
(5) BHP-hrH = Total brake horsepower-hour (brake horsepower integrated with respect to time) for the hot-start test.
(b) The mass of particulate for the cold-start test and the hot-start test is determined from the following equation:
(1) Pmass = Mass of particulate emitted per test phase, grams per test phase. (PH = Pmass for the hot-start test and PC = Pmass for the cold-start test.
(2) Vmix = Total dilute exhaust volume corrected to standard conditions (528° R (293° K) and 760 mm Hg (101.3 kPa)), cubic feet per test phase. For a PDP-CVS:
(2)(i)(A) For a CFV-CVS: Vmix = Total dilute exhaust volume corrected to standard conditions (293 °K (20 °C) and 101.3 kPa (760 mm Hg)), cubic feet per test phase.
(B) For a PDP-CVS:
(ii) Vo = Volume of gas pumped by the positive displacement pump, cubic feet (cubic meters) per revolution. This volume is dependent on the pressure differential across the positive displacement pump.
(iii) N = Number of revolutions of the positive displacement pump during the test phase while samples are being collected.
(iv) PB = Barometric pressure, mm Hg (kPa).
(v) P4 = Pressure depressions below atmospheric measured at the inlet to the positive displacement pump (during an idle mode), mm Hg (kPa).
(vi) Tp = Average temperature of dilute exhaust entering the positive displacement pump during test, °R (°K).
(3) Vsf = Total volume of sample removed from the primary dilution tunnel, cubic feet at standard conditions.
(i) For a single-dilution system:
(A) Vas = Actual volume of dilute sample removed from the primary-dilution tunnel, cubic feet.
(B) PB = Barometric pressure, mm Hg.
(C) Pis = Pressure elevation above ambient measured at the inlet to the dilute exhaust sample gas meter or flow instrumentation, mm Hg. (For most gas meters or flow instruments with unrestricted discharge, Pis is negligible and can be assumed = 0.)
(D) Tis = Average temperature of the dilute exhaust sample at the inlet to the gas meter or flow instrumentation, °R.
(E) Vsf may require correction according to §86.1320-87(a)(6).
(ii) For a double-dilution system:
Vsf = Vvf − Vpf′
(B) Vav = Actual volume of double diluted sample which passed through the particulate filter, cubic feet.
(C) PB = Barometric pressure, mm Hg.
(D) Piv = Pressure elevation above ambient measured at the inlet to the sample gas meter located at the exit side of the secondary-dilution tunnel, mm Hg. (For most gas meters with unrestricted discharge Piv is negligible and can be assumed = 0.)
(E) Tiv = Average temperature of the dilute exhaust sample at the inlet to the exit side gas meter or flow instrumentation, °R.
(G) Vap = Actual volume of secondary dilution air, cubic feet.
(H) Pa = Barometric pressure, mm Hg.
(I) Pip = Pressure elevation above ambient measured at the inlet to the sample gas meter or flow instrumentation located at the inlet side of the secondary dilution tunnel, mm Hg. (For most gas meters with unrestricted discharge Pip is negligible and can be assumed = 0.)
(J) Tip = Average temperature of the secondary dilution air at the inlet to the inlet side gas meter or flow instrumentation, °R.
(K) Both Vvf and Vpf may require correction according to §86.1320-87(a)(6). These corrections must be applied before Vsf is determined.
(4) Pf = Mass of particulate on the sample filter (or sample and back-up filters if the back-up filter is required to be included, see §86.1339-87(g) for determination), grams per test phase.
(5) Pbf = Net weight of particulate on the background particulate filter, grams.
(i) Vab = Actual volume of primary dilution air sampled by background particulate sampler, cubic feet.
(ii) Pib = Pressure elevation above ambient measured at the inlet to the background gas meter or flow instrument, mm Hg. (for most gas meters or flow instruments with unrestricted discharge, Pib is negligible and can be assumed = 0.)
(iii) Tib = Average temperature of the background sample at the inlet to the gas meter or flow instrument, °R.
(7) For definition of DF see §86.1342-84(d)(5).
(8)(i) Real time flow rate measurement and calculating devices are permitted under these regulations. The appropriate changes in the above calculations shall be made using sound engineering principles.
(ii) Other systems and options, as permitted under these regulations, may require calculations other than these, but these must be based on sound engineering principles and be approved in advance by the Administrator at the time the alternate system is approved.
(Secs. 202, 203, 206, 207, 208, 301a, Clean Air Act, as amended; 42 U.S.C. 7521, 7522, 7525, 7541, 7542, 7601a)
[50 FR 10706, Mar. 15, 1985, as amended at 52 FR 47876, Dec. 16, 1987; 62 FR 47135, Sept. 5, 1997]