Effects of ethanol-blended gasoline on emissions of regulated air pollutants and carbonyls from motorcycles

The emission characteristics of regulated air pollutants and carbonyls from motorcycles using gasoline blended with 3% ethanol (E3) and gasoline (E0) were investigated in this study. Nine motorcycles were operated on a chassis dynamometer and driven according to the ECE driving cycle for air pollutant measurements. In addition, durability testing was performed on two brand-new motorcycles of the same model, using E3 in one and E0 in the other, to assess the effects of E3 usage on motorcycle emissions. The results show that average emission factors of CO and THC decreased by 20.0% and 5.27%, respectively, using E3 fuel. However, NOx and CO2 emission increased by 5.22% and 2.57%. The results of paired t-tests indicate that only the reduction of CO emission is statistically significant (p-value = 0.006). The emission factors of ∑15 carbonyls for the nine test motorcycles were 1289 ± 502 and 1579 ± 368 μg/km for E0 and E3, respectively. Carbonyl emission increased by 22.5% using E3 substituted for E0. However, the differences in ∑15 carbonyl emission between E0 and E3 were not statistically significant (p-value = 0.137). Among the 15 analyzed carbonyls, only the emission of acetaldehyde was significantly higher (p-value = 0.014) with E3. The results of durability tests show that deterioration coefficients for E3 were 1.50, 1.45, 0.84, 0.94 and 1.06 for CO, THC, NOx, CO2 and carbonyls, respectively. Statistical tests exhibit that using E3 as fuel does not increase the regulated air pollutants, nor carbonyl emissions for the durability test.