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INFLUENCE OF AMBIENT TEMPERATURE ON TAILPIPE EMISSIONS FROM LATE MODEL LIGHT-DUTY GASOLINE MOTOR VEHICLES
Citation:
Stump, Tejada, Ray, Dropkin, AND Black. INFLUENCE OF AMBIENT TEMPERATURE ON TAILPIPE EMISSIONS FROM LATE MODEL LIGHT-DUTY GASOLINE MOTOR VEHICLES. U.S. Environmental Protection Agency, Washington, D.C., EPA/600/J-89/019 (NTIS PB89237473).
Description:
Motor vehicle emissions are sensitive to a number of variables including ambient temperature, driving schedule (speed vs time), and fuel composition. ydrocarbon, aldehyde, carbon monoxide, and oxides of nitrogen emissions were examined with nine recent technology 4-cylinder gasoline motor vehicles at 70F, 40F, and 20F. bout 200 hydrocarbon and 12 aldehyde compounds were included in the organic emissions characterization. Two fuels and two driving schedules were used. ypically, hydrocarbon and carbon monoxide emissions were significantly increased by reduced ambient temperature. xides of nitrogen emissions also increased, but to a lesser extent. There were no predictable formaldehyde emissions trends with temperature. araffinic and aromatic hydrocarbon emission fractions were sensitive to fuel composition, but the olefinic emission fraction (dominated by ethylene and propylene) was not. ith low temperature cold start tests, preceding transient driving with a 5 minute engine idle resulted in reduced carbon monoxide emission rates and elevated oxides of nitrogen emission rates. ydrocarbon emission rates were not predictablY sensitive to the preliminary idle.