Effects of CNG Heating Value on Combustion Characteristics of a Diesel-CNG Dual-Fuel Engine

디젤-CNG 혼소엔진에서 CNG 발열량 변화가 연소 특성에 미치는 영향

Kim, Yongrae;Jang, Hyeongjun;Lee, Janghee;Kim, Changgi

  • Received : 2015.12.04
  • Accepted : 2015.12.24
  • Published : 2015.12.31


In this study, a dual fuel engine fueled with natural gas and diesel was tested to investigate the effects of heating value variation of CNG fuel. CNG substitution rate which is defined as the ratio of CNG and diesel supplied in a heating value basis was fixed at 80%. The higher heating value was varied from $10,400kcal/Nm^3$ to $9,400kcal/Nm^3$ by mixing nitrogen gas with pure CNG and diesel fuel was injected at a fixed injection timing. The engine test results showed that thermal efficiency and power output were decreased as the heating value of mixed CNG fuel was decreased. And the peak cylinder pressure was also decreased but the ignition delay time and the combustion duration and timing were almost same.


dual fuel engine;heating value variation;cng substitution rate;thermal efficiency


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Supported by : 한국가스공사, 에너지기술평가원