Carbonyl compound emissions from passenger cars fueled with methanol/gasoline blends

Carbonyl compound emissions from two passenger cars fueled with different methanol/gasoline blends (M15 and M100) and operated with three-way catalytic converters (TWC) were investigated. The tests were performed on a chassis dynamometer with constant volume sampling over the New European Driving Cycle (NEDC). Carbonyls were trapped on dinitrophenylhydrazine (DNPH) cartridges. The hydrazones formed on the cartridge were analyzed by means of high-performance liquid chromatography (HPLC) and detected with a variable wavelength detector. The results show that when cars were fueled with methanol/gasoline blends, carbon monoxide (CO) and total hydrocarbon (THC) emissions decreased by 9-21% and 1-55% respectively, while nitrogen oxide (NO_x) emissions increased by 175-233%. Compared with gasoline vehicles, formaldehyde emissions with M15 and M100 were two and four times higher respectively, and total carbonyls with M15 and M100 increased by 3% and 104% respectively. With the use of the new TWC, both regulated gas pollutants and formaldehyde decreased. The new TWC caused a decrease of 5% and 31% in formaldehyde concentration for M15 and M100, respectively. Specific reactivity (SR) with the new TWC was reduced from 5.92 to 5.72 for M15 and from 7.00 to 6.93 for M100, indicating that M15 and M100 with the new TWC were friendlier to the environment.