EGR 장착 스파크점화 LPG엔진의 성능 및 배기 특성

Abstract

EGR(Exhaust Gas Recirculation) system has been used to reduce NOx emissions, improve fuel economy, and decrease thermal loading of engine because it offers the benefits of charge dilution as is the case with a lean burn technique. It is currently used in conventional engines, especially light-duty gasoline and diesel engines for a variety of advantages, and in recent years, it has become as a means of reducing engine-out emissions for heavy-duty vehicles as a consequence of the development of its control schemes as well. However, the occurrence of excessive cyclic variation with high EGR rates, especially at high load conditions, brings about the undesirable combustion instability within the engine cylinder, which results in the deterioration of both engine performance and emissions. Therefore, in order to avoid the reduction of thermal efficiency and to improve fuel economy, the optimum EGR rate depending on operating conditions of engine, should be derived effectively. An experimental study was conducted to investigate the effects of EGR on performance and emission characteristics of a spark-ignition LPG fuelled engine, and the feasibility of an enhanced methodology, such as a cooled EGR system.