Investigating the effect of using catalytic converters and changing fuel supply system on motorcycle emission performance

As motorcycles are named as one of the important air pollution emission sources in Tehran, investigating their emission performance and finding a solution for reducing their emission is of high importance. In this study, emission factors from 60 motorcycles from Tehran’s present fleet and 4 closed loop injection fuel supply system and catalytic converter equipped motorcycles were measured. Measurements were taken in chassis dynamometer Laboratory according to Euro-3 standard procedure in ECE driving cycle. Tests results showed that CO emission factor from Tehran’s present motorcycles are 7 times higher than Euro-3 certification limit. It was indicated that about 40% of carbon in fuel burns to incomplete combustion product in Tehran’s present motorcycles. Using carburetor fuel supply system is responsible for this emission performance. Test results showed that CO and THC emission factors of injection and catalyst equipped motorcycles are 87% and 75% less than that of Tehran’s present motorcycles respectively. Total pollutants emissions caused by Tehran’s motorcycles in morning peak hour were estimated. It was revealed that, by replacing Tehran’s present motorcycle with closed loop injection fuel supply system and catalyst equipped motorcycles, CO, THC and NOX emissions from motorcycles in morning peak hour would reduce by 88, 88 and 46% respectively.