Abstract
Influence of a catalytic converter on wave motion in an exhaust pipe of a two-stroke engine was studied through experiment and simulation. In the experiment, pressure wave was generated by a single pulse generator developed from a commercial 125 cc two-stroke engine. The pressure wave was allowed to travel from a pulse generator through an exhaust pipe both with and without catalytic converter. Pressure wave propagation was monitored at the same position along the exhaust pipe system and then compared with the simulated results. Parameters affecting the amplitude of the pressure wave are studied and the results are verified by the simulated ones. The simulation model is successfully applicable for the prediction of the overall wave propagation of the two-stroke engine exhaust system. Experimental results show that the amplitude of the pressure wave is decreased mainly due to the reflection of the pressure wave at the catalytic converter and the friction of the catalytic converter. Simulated results reveal that installation of catalytic converter with cell density of 400 CPI between the exhaust port and the muffler reduces the exhaust mass flow by approximately 27 percent. The significant of this research result is that installation of catalytic converter at the exit of muffler causes the negligible affect on the exhaust flow of the two-stroke engine.