Research Projects

The purpose of this work was to examine the potential of determining running loss emissions by examining the sources of evaporation of fuel from a vehicle during operation. This required the use of equipment based on constant volume sampling with multiple sources that could simultaneously monitor different locations. The hydrocarbon emissions were measured for their total content with two California certified vehicles. The operating temperature and fuel vapor pressure were control variables that were examined for their effect. Evaporative running losses were found at the charcoal canister and purge air vent. Differences in the losses were observed with the two vehicles. The fuel vapor pressure and driving cycle were major factors over the ranges examined, but temperature had statistical significance. A model used to predict vapor generation from the fuel was in general agreement with the running loss experimental data.