엔진 공회전시 엔진 제어변수 조작에 따른 배기배출 및 연소안정 특성

Fast warm up of catalyst and combustion stability are crucial for the reduction of harmful emission during cold start of an SI engine. In this study, raw emissions and pressure variations are measured and analyzed with the changes of spark and exhaust valve timings. A combustion analyzer, designed for this study, helps investigations of the combustion stability from the data of pressure variations. Through this study, it is observed that changes of timings can cause the improvement of COV and emissions. It is expected that a proper control strategy for cold start will cause the reduction of harmful emissions and increase of the combustion stability.