Investigation on characteristics of exhaust and evaporative emissions from passenger cars fueled with gasoline/methanol blends

Exhaust and evaporative emissions including regulated and unregulated pollutants emitted from a passenger car fueled with gasoline and M15 fuel (M15 means the fuel was consisted with 85%gasoline and 15% methanol by volume) were discussed in this paper. To improve the measurement accuracy of the unregulated pollutants, the dilution air refine system (DAR) was introduced. The exhaust emission tests were performed on the chassis dynamometer, emission factors were measured by a constant volume sampling (CVS) system equipped with DAR over the New European Driving Cycle (NEDC). The evaporative emission tests were performed in the Sealed Housing for Evaporative Determination (SHED). Carbonyls, volatile organic compounds (VOCs) and methanol were sampled through the battery-operated air pumps using tubes coated with 2,4-dintrophenylhydrazine (DNPH), Tenax TA and silica gel respectively. The test results show that comparing with gasoline operations, THC and CO from passenger car fueled with M15 decreased by 16% and 7% while the NO_X increased by 85%. The formaldehyde emitted from M15 fueling passenger car was almost two times larger than that from gasoline fueling. For the evaporative emissions, diurnal losses are far more than hot losses and turn out to be the main contributor to the evaporative emissions. For different fuels, evaporative THC from M15 increased by 63%. Given the unregulated pollutants, carbonyls and VOCs increased by 19% and 23%. Moreover, methanol from M15-fueling car was 128 times higher than that from gasoline fueling. It is important to research new canister to decrease the evaporative emissions.