직접분사식 엔진의 성층화 연소 및 안정성에 관한 연구

Lean burn gasoline engine, classified into port injection and direct injection, is recognized as a promising way to meet better fuel economy. Especially, gasoline direct injection engine is becoming increasingly popular due to their potential for improved fuel economy and emissions. Also, GOI engine has the advantages of higher power output, higher thermal efficiency, higher EGR tolerance due to the operation characteristics of increased volumetric efficiency, compression ratio and ultra-lean combustion scheme. However, GDI engine has many difficulties to be solved, such as complexity of injection control mode(fuel injection timing, injection rate), fuel injection pressure, spark timing, unburned hydrocarbon and restricted power. This study is investigated to the influence of spark timing, fuel injection position and fuel injection rate on the combustion stability of GDI engine. Piston shape is constituted the bowl type piston. The characteristics of combustion is analyzed with the variations of spark timing, fuel injection position and fuel injection rate (early injection, late injection) in a GDI engine.