On cold start operation of a gasoline engine, a catalyst shows poor performance before it reaches activation temperature. Therefore, fast warmup of the catalyst is very crucial to reduce harmful emissions. In this study, an appropriate control strategy is investigated to increase exhaust gas temperature through changes of exhaust valve timing. An advance of exhaust valve timing decreases residual gas in cylinders due to decrease of valve overlap period. A control strategy of proper valve timing is suggested in order to achieve fast light-off of the catalyst and stable operation of the engine in a cold start and idle operation.

Abstract   1. 서 론   2. 이론 해석    2.1 흡기 및 배기밸브 타이밍의 효과    2.2 가변밸브 타이밍   3. 실험 방법 및 결과    3.1 실험 장치 및 방법    3.2 냉시동 특성 실험장치의 구성 및 개략도    3.3 실험 결과   4. 결 론   참 고 문 헌

• 함성훈(동주대학 자동차튜닝과) | S. H. Ha
• 권영웅(서일대학 자동차과) | Y. W. Kwo