Abstract:
There are several constraints in retrofitting catalytic converter to two-stroke motorcycle engines. The constraints might affect the conversion efficiency and engine performance. Exhaust gas temperature at inlet of catalytic converter is one of vital parameters. Also the location of catalytic converter in the exhaust pipe will affect engine performance in difference degrees. The aims of this research work are to investigate the effect of catalytic converter on engine performance, on fuel consumption and to monitor temperature profile along the exhaust pipe. Moreover a simulation to predict heat loss from an exhaust pipe is constructed and verified with the test data. In the study a two-stroke engine with displacement of 110 cc was used and test runs were conducted both on engine test-bed and chassis dynamometer.The results show that retrofitting a hot-tube (a partial-flow catalytic converter) at the distance of 80 cm from the exhaust port slightly effect on power and fuel consumption. However, emission levels decrease modestly. At half throttle opening, carbon monoxide and hydrocarbon are reduced by 26 percent and 17 percent, respectively. While at full throttle position, carbon monoxide and hydrocarbon are reduced by 15 percent and 20 percent, respectively. It is noticed that after the catalytic converter reached operating temperature, it is still active at even lower temperatures. In conclusion, the retrofitting of a hot-tube at the distance of 80 cm is not feasible in practice since the conversion efficiencies are comparatively low.Comparison of gas temperatures along the exhaust pipe without the hot-tube shows good agreement between calculation and experiment. The siinulation can be used to predict a suitable location for retrofitting the hot-tube in two-stroke engine exhaust pipe.