Effects of Fuel Properties on Mass Exhaust Emissions During Various Modes of Vehicle Operation

The analysis of data from the Auto/Oil Air Quality Improvement Research Program (AQIRP) study of the effect of aromatics, MTBE, olefins, and T₉₀ on mass exhaust emissions from current (1989) vehicles was extended to include individual vehicles during individual operating modes.

The results of the modal data analysis agree with and complement results which have been reported previously by AQIRP. Beyond this, attention is focused on three fuel compositional changes where the effect on emissions shows a reversal in sign depending on the vehicle operating mode chosen.