Development of a Fuel-Based Mass Emission Measurement Procedure 710604
A calculational procedure is derived which expresses exhaust emissions on a fuel basis. Existing vehicle exhaust sampling procedures are utilized, together with fuel consumption data which are simultaneously obtained. Since no measurements of exhaust or air flow are required, the procedure is not limited by powerplant size.
Emission values are computed in terms of grams per mode and grams per mile, as well as on “corrected” molar concentration (fuel) bases. Additional calculated vehicle developmental parameters include air-fuel ratio (carbon balance and oxygen balance), air consumption, dry exhaust volume, fuel economy, and combustion efficiency. Conversion of wet exhaust analyses to dry bases is considered.
Actual mass emissions are determined for both the current federal seven-mode cycle and the 1972 federal test cycle. The observed, uncorrected vehicle concentration data, together with fuel flow data obtained by means of a digital fuel meter, are reduced by means of an on-line computer installation. In addition to tests of lean, catalytic, and rich reactor vehicles, this procedure has been employed for vehicles powered by gas turbine, steam, diesel, and hybrid ICE-electric powerplants, including some vehicles in the 1970 “Clean Air Car Race.”