|Title||Behzad, 박성산, 배충식, “분사시기와 분사량이 저온연소-기존연소간 모드 전환 안정성에 미치는 영향”, 2014 한국자동차공학회 부문종합 춘계학술대회, 2014. 05|
Implementation of Low Temperature Combustion (LTC) mode in diesel engines contributes to lower emissions, however the limited operational range is a challenge that should be dealt with. Mode changing between conventional mode and LTC is a potential solution to this problem therefore possibilities of smooth mode transition between two modes should be explored. In this paper effects of injection strategies on mode transition were studied in a heavy duty single cylinder engine when mode transition happened from LTC to conventional mode. The Exhaust Gas Recirculation (EGR) line was equipped with a servo valve actuator that can close and open the EGR line in one cycle only. Base experiment with no injection strategy showed that the engine goes through almost ten cycles of instable Indicated Mean Effective Pressure (IMEP) therefore different patterns of change in injection timing and fuel compensation was applied to ten cycles. It was observed that the injection timing should be changed in a nonlinear way and preferably before the EGR change happens to minimize the instabilities. Fuel compensation or adjusting the fuel quantity during the mode transition cycles was also applied as a measure to control the instabilities and it showed to be a rather effective factor. A sensitivity analysis was then carried out on the injection timing and injection quantity to see which one is the more dominant factor to control the instabilities and also to find out which cycle during the mode transition is the most sensitive cycle to above mentioned changes. A step equal to one fourth of the whole span of change in injection timing and quantity was applied to timing and quantity respectively in each cycle to see the effect on overall Coefficient of Variation (COV) of IMEP during the mode transition. It was observed that instability shows generally more sensitive to the injection quantity rather than the injection timing. For the cycle sensitivity, our results indicate that the sensitivity to both injection timing and injection quantity is increased considerably at the cycles during which the changes in EGR happens in the cylinder (fig 1).
|Previous||황준식, 배충식, “대형 디젤 엔진에서 연소실 내부의 직접 가시화를 통한 폐식용유 바이오디젤과 디젤의 분무 및 화염 특성 분석”, 제 47회 KOSCO Symposium, 2013.12|
|Next||주용준, 정진영, 배충식, “프로판과 노말 부탄의 분무특성 연구”, 2014 한국자동차공학회 부문종합 춘계학술대회, 2014. 5|