Emissions of gaseous pollutant from motorcycle powered by ethanol–gasoline blend

Two four-stroke motorcycles equipped with carburetor and fuel-injected engine, respectively, had been tested to evaluate the effect of ethanol–gasoline blend on gaseous pollutant emissions. Blend gasoline contains 15% (vol) ethanol (E15) and commercial unleaded gasoline (G95) was used as test fuels. Emission test had been conducted on a chassis dynamometer with the Economic Commission for Europe (ECE) cycle. Criteria air pollutants (CO, THC, and NOx) and organic air pollutants were analyzed. The results showed that emission of CO from E15 decreased by 32% (carburetor) and 10% (fuel-injection), respectively, compared with those of G95. THC emissions also showed a reduction by 10% for fuel-injected engine, but did not reduce emissions from carburetor engine. No significant decrement of NOx emission was observed as using E15. Organic air pollutant emission factors of E15, except carbonyl, were lower than those of G95 for both test motorcycles. High emission of acetaldehyde was observed while using ethanol blend. The ozone-forming potential of motorcycle engine exhaust also reduced as using E15 blend instead of commercial gasoline.