듀얼 포트 분사식 인젝터와 흡기 밸브 열림 시기 연료 분사 전략 사용에 따른 포트분사식 가솔린 엔진의 전부하 성능 향상에 대한 연구

The DISI (Direct injection Spark Ignition) engines are becoming widely adopted as the higher specific power can be realized for DISI engines compared to the former PFI (Port Fuel Injection) engines. The underlying mechanisms of higher specific power of DISI engines are cooling effect of air due to evaporation of injected fuel and advancement of ignition timing due to fuel stratification. In DISI engines, however, wall impingement of fuel and formation of locally rich air-fuel mixture lead to increase in the THC (Total Hydrocarbon) and PM emission. If the fuel is injected when the intake vales are open in PFI engines, it is possible to utilize the cooling effect and ignition timing advancement like in DISI engines and increase the maximum power of engine. Such injection strategy is called OVI (Open Valve Injection). Previous studies on OVI were focused on the emission characteristics of engines rather than the power output of engine. Therefore, in this research, the effect of OVI on both the engine out emission and maximum power of engine was observed. The experiments to were conducted at WOT (Wide Open Throttle) condition, and increase in IMEP was observed while PM emission was lower than that of DISI engines at the same experimental condition.