근사적 열발생율에 의한 예연소실식 디젤기관의 연소해석

Combustion Analysis in a Pro-Combustion Chamber Diesel Engine by Approximate Heat Release Rate

예연소실식 디젤기관에 있어서 박용부하운전조건에 따른 연소특성을 규명하기 위해 예언소실의 압력데이터를 single-zone, single-chamber의 열역학적 해석에 적용하여 연소해석을 행한 결과 다음과 같은 결론을 얻었다. 1) 부하가 증가함에 따라 최고압력이 상승하고 그 위치가 크랭크각도상 후진되었다. 2) 착화 지연시간은 부하에 관계없이 거의 일정하고, 부하가 증가할수록 가연 혼합기 형성에 소요되는 흡열량은 겉보기로 감소하였다. 3) 예혼합 연소단계의 열발생 양상은 부하에 관계없이 거의 비슷하고, 예혼합 연소시간은 부하가 증가할수록 짧아졌다. 4) 부하가 증가함에 따라 예혼합 연소량은 다소 증가하나 일정 연공비 이상에서는 거의 일정했다. 5) 예혼합 연소분율은 부하가 증가함에 따라 감소했다.(이 논문의 결론부분임)

In this study, the combustion characteristics in a pre-combustion chamber diesel engine was investigated with experimental conditions of marine engine load. The heat release analysis used was a single-zone single-chamber thermodynamic analysis based on pre-combustion chamber pressure-time data. Based on the results of this investigation, the following conclusions were reached: 1) Increasing the load, peak pressure was increased and position of P sub(max) was retarded in crank angle degrees. 2) Ignition delay time was almost constant without relating to the load and the heat values to form a combusitible mixture were decreased apparently with increasing the load. 3) In premixed-combustion mode, the pattern of heat release rate was resembled without relating to the load and premixed-combustion time was shortened with increasing the load. 4) Increasing the load, mass of premixed-burned fuel was increased slightly, but was invariable beyond a certain fuel-air ratio. 5) Increasing the load, premixed-burned fraction was decreased.