EGR 성층화가 액상분사 LPG엔진의 성능에 미치는 영향

Abstract

EGR (exhaust gas recirculation) utilizes the diluents into the engine cylinder to control combustion leading to enhanced fuel economy and reduced emissions. However, with high diluent rate, the occurrence of excessive cyclic variation brings about an undesirable combustion instability resulting in the deterioration of engine performance. Proper stratification of diluent could improve the combustion stability under high diluent environment. EGR stratification within the cylinder was made by adopting a fast-response solenoid valve in the midst of EGR line and controlling its timing and duty. With supplying EGR in both homogeneous mode and stratified mode, thermodynamic heat release and flame propagation characteristics were investigated in an optically accessible single cylinder engine. Shorter burning duration and faster flame propagation were found in the case of stratified EGR than homogeneous EGR PLIF images gave the EGR distribution within cylinder to show that EGR occupied the lower part of cylinder through the stratification process and this could help reducing the burning duration.