On cold start operation of an SI 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 spark timing. Combustion stability is also considered at the same time. Exhaust gas temperature and pressure of combustion chamber are measured to investigate the effects of spark timings on cold start and idle performance. Experiments showed that retarded spark timing promotes the combustion at the end of expansion stroke and increases exhaust gas temperature during cold start.

Abstract
 1. 서론
 2. 가솔린기관의 작동 조건과 유해배출의 상관성
 3. 실험장치의 구성 및 결과
  3.1 냉시동 특성 실험장치의 구성
  3.2 실험결과 및 고찰
 4. 결론
 참고문헌

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