Abstract
Abstract:
Conventional 2-stroke engines have defects such as unstable combustion, high fuel consumption rate, and high HC emissions. In order to overcome the defects, a direct fuel injection system and a new scavenging system were adopted. The authors tested a newly developed reverse-uniflow type 2-stroke direct injection gasoline engine, that was designed by numerical simulations. In comparison with the base engine, HC emission was decreased by up to 80%, and BSFC was reduced by around 40%. Power and BSFC were sperior to that of a latest 4-stroke engine. Furthermore, the effects of the start of injection timing and the fuel spray amount on the diffusion of fuel were examined by performance tests and numerical simulations, and the process was found important to improve the engine performance.