40 CFR §86.143-96

1. (a)The following equations are used to calculate the evaporative emissions from gasoline- and methanol-fueled vehicles, and for gaseous-fueled vehicles.
2. (b)Use the measurements of initial and final concentrations to determine the mass of hydrocarbons and methanol emitted. For testing with pure gasoline, methanol emissions are assumed to be zero.
   1. (1)For enclosure testing of diurnal, hot soak, and running loss emissions:
      1. (i)Methanol emissions:
      2. (ii)Hydrocarbon emissions:
      3. (iii)For variable-volume enclosures, defined in § 86.107(a)(1)(i), the following simplified form of the hydrocarbon mass change equation may be used:
   2. (2)For running loss testing by the point-source method, the mass emissions of each test phase are calculated below, then summed for a total mass emission for the running loss test. If emissions are continuously sampled, the following equations can be used in integral form.
      1. (i)Methanol emissions:
      2. (ii)Hydrocarbon emissions:
3. (c)If the test fuel contains at least 25% oxygenated compounds by volume, measure the concentration of oxygenated compounds directly using a photoacoustic analyzer specified in 40 CFR 1065.269 or using impingers as described in 40 CFR 1065.805(f). Calculate total hydrocarbon equivalent emissions with the following equation, using density values specified in 40 CFR 1066.1005(f):
4. (d)
   1. (1)For the full three-diurnal test sequence, there are two final results to report:
      1. (i)The sum of the adjusted total mass emissions for the diurnal and hot soak tests (MDI + MHS); and
      2. (ii)The adjusted total mass emissions for the running loss test, on a grams per mile basis = MRL/DRL, where DRL = miles driven for the running loss test (see § 86.134-96(c)(6)).
   2. (2)For the supplemental two-diurnal test sequence, there is one final result to report: the sum of the adjusted total mass emissions for the diurnal and hot soak tests (MDI + MHS), described in §§ 86.133-96(p) and 86.138-96(k), respectively.