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연료의 불균질성을 갖는 DME HCCI엔진에서 부스터효과에 관한 수치해석
권오석(OSeok Kwon),홍성태(Sungtae Hong),임옥택(OckTaeck Lim) 한국자동차공학회 2009 한국자동차공학회 부문종합 학술대회 Vol.2009 No.4
The purpose of this study is to gain a better understanding of the effects of fuel stratification on reducing the pressure-rise rate at high load in HCCI combustion. It was found that fuel stratification offers good potential to achieve a staged combustion event and reduced pressure-rise rates. The engine is fueled with Di-Methyl Ether (DME) which has unique 2-stage heat release. Numerical analysis is conducted with single and multi-존s model and detailed chemical reaction scheme is done by chemkin and senkin. Calculation result shows that proper fuel stratification prolongs combustion duration and reduce pressure rise rate. Besides IMEP, combustion efficiency and indicated thermal efficiency keep constant. However, too wide fuel stratification increases pressure rise rate and CO and NOx emissions in exhaust gas.
운행자동차의 공회전 정지에 의한 CO₂ 저감량 산출 연구
심무경(Mookyung Shim),임재명(Jay-Myoung Rim),이범호(Beomho Lee),홍성태(Sungtae Hong),이대엽(Daeyup Lee) 대한기계학회 2009 大韓機械學會論文集B Vol.33 No.10
The effect of idling stop on CO₂ reduction was estimated, especially in the area of in-use vehicles. In order to know the fuel saving for each class of vehicles, a methodology to calculate the fuel saving was used along with a standard test using NIER-07 mode. Idling stop execution rate was estimated by analyzing the driving pattern of the in-use city buses, which shows about 75% at maximum. And this corresponds to about 5.4% reduction of the daily total fuel consumption. Finally, CO₂ reduction in the automotive sector was estimated, which concludes that, when idling stop device is used, about 480 thousand and 450 thousand tons of CO₂ could be reduced with in-use city buses and taxis, respectively. This amount corresponds to about 1.2% of CO₂ reduction in the automotive sector.
5.9리터급 LPG MPI 엔진에서 희박 연소 특성의 향상
곽용환(Yonghwan Kwak),이범호(Beomho Lee),이대엽(Daeyup Lee),박영표(Youngpyo Park),홍성태(Sungtae Hong) 한국자동차공학회 2008 한국자동차공학회 춘 추계 학술대회 논문집 Vol.- No.-
In medium and heavy duty engines for vehicles heavier than 3.5 tons(GVW), an implementation of lean burn technology is very important to lower thermal load and enhance fuel economy. To meet EURO-5 emission regulations, the optimized emission characteristics are also important design factors. In this work, with lean burn technology, a swirl enhancing valve was used in the intake port to improve combustion. Also, the injection position was varied to see its effect on stratification of air fuel mixture, which thus may enhance lean burn characteristics. This work concludes that, when the fuel was injected toward tumble port, the COV became flat over the wider range of ignition timing and the exhaust temperature was lowered. And, with tumble port injection, the torque was slightly increased and there exist conditions where NOx was reduced at the same level of torque compared with the baseline case.