단기통 액상분사 LPG 엔진의 EGR효과

Abstract

Exhaust Gas Recirculation (EGR) system was used to reduce NOx emissions, to improve fuel economy and to suppress knock since it offers the benefits of charge dilution In this research EGR was adopted to reduce the thermal load on the exhaust manifold, since the reduced gas temperature is desirable for the reliability of an engine in light of both thermal efficiency and material issue of exhaust manifold. However, the occurrence of excessive cyclic variation with high EGR rates brings about an undesirable combustion instability within the engine cylinder resulting in the deterioration of both engine performance and emissions. For a LPG fueled engine, use of mixer and vaporizer gives its way to liquid phase port injection Improved volumetric efficiency gives more power and accurate air-fuel ratio gives less amount of hazardous emission. In this research, the investigation of the effects of EGR on the reduction of thermal loading at exhaust manifold was performed in a single cylinder liquid-phase LPG injection engine. The effects of EGR variables (a wide range of EGR rates and EGR Temperature) on power and emission characteristics ware also investigated. As a result, the optimum EGR rate was derived effectively as a function of the operating conditions.