40 CFR 90.419 - Raw emission sampling calculations - gasoline fueled engines.
(a) Derive the final weighted brake-specific mass emission rates (g/kW-hr) through the steps described in this section.
(b)Air and fuel flow method. If both air and fuel flow mass rates are measured, use the following equations to determine the weighted emission values for the test engine:
(c)Fuel flow method. The following equations are to be used when fuel flow is selected as the basis for mass emission calculations using the raw gas method.
KH = Factor for correcting the effects of humidity on NO2 formation for 4-stroke gasoline small engines, as follows:
KH = (9.953 × H 0.832)
(d) Calculate the final weighted brake-specific emission rate for each individual gas component using the following equation: