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링간 틈새체적에서의 가스유동이 UHC 배출물에 미치는 영향
김창기(C.G.Kim),배충식(C.S.Bae),최상민(S.M.Choi) 한국자동차공학회 1998 한국자동차공학회 춘 추계 학술대회 논문집 Vol.1998 No.11_1
The effect of the inter-ring crevice, the volume between the top and the second piston rings, on unburned hydrocarbon (UHC) emission was experimentally and numerically investigated. The ultimate goal of this study was to reduce the level of UHC emission by minimizing the blow-up of the unburned gases trapped in the inter-ring crevice. For this purpose, the unburned mixture trapped in the inter-ring crevice was extracted to the crankcase during the late period of the expansion stroke and the early period of the exhaust stroke through the engraved grooves on the lower part of the cylinder wall. The extraction of the mixture from the inter-ring crevice resulted in significant reductions of UHC emission over a range of speeds and loads, without any losses of efficiency and power. A physical model for predicting the gas flow into and from the inter-ring crevice was also adopted to simulate the effect of the grooves on the lower part of cylinder wall. The calculated results agreed well with the measurements and could explain the mechanism of UHC emission reduction achieved with the grooved cylinder liners. This consistency has confirmed the importance of the inter-ring crevice on UHC emission in an SI engine.<br/>
링간 혼합기가 SI 엔진의 미연탄화수소 배출에 미치는 영향
김창기(C.G.Kim),최상민(S.M.Choi),배충식(C.S.Bae) 한국자동차공학회 1998 한국자동차공학회 춘 추계 학술대회 논문집 Vol.1998 No.5_1
The effect of the inter-ring crevice, the volume between the top and the second piston rings, on unburned hydrocarbon (UHC) emission was experimentally investigated. The ultimate goal of this study is to reduce the level of UHC emission by minimizing the effect of the inter-ring crevice. For this purpose, the unburned mixture trapped in the inter-ring crevice was extracted to the crankcase during the late period of the expansion stroke and the early period of the exhaust stroke through the engraved grooves on the lower part of the cylinder wall. The extraction of the mixture resulted in significant reductions of UHC emission over a range of speeds and loads, without any losses of efficiency and power. The effect of the inter-ring crevice on UHC emission in an SI engine was obvious.<br/>
김창업(C.U.Kim),김창기(C.G.Kim),김승수(S.S.Kim),방효선(H.S.Bang),한정옥(J.O.Han),조양수(Y.S.Cho) 한국자동차공학회 1994 한국자동차공학회 춘 추계 학술대회 논문집 Vol.1994 No.11_1
Lean combustion is one of the most promising method for increasing engine efficiency and reducing the exhaust emission from SI gas engines. Due to the possibility of partial burn and misfire, however, under lean bum operation, stable flame kernel formation and fast bum rate are needed to guarantee a successful subsequent combustion.<br/> Experiment data were obtained on a 4-stroke, natural gas fueled SI engine to investigate the effect of compression ratio, swirl, spark plug electrode rotation, center electrode shape and electrode gap width on efficiency and emission.<br/> Experiment has shown that higher compression ratio, swirl vane, favorable rotation of electrode and wider electrode gap width improve the efficiency and stability of engine under lean operational condition.<br/>
[연료 및 윤활유부문] 저공해 대형엔진용 대체연료로서 LPG적용성에 대한 연구
강건용(K.Y.Kang),김창기(C.G.Kim),이상석(S.S. Lee),이진욱(J.W.Lee) 한국자동차공학회 2000 한국자동차공학회 춘 추계 학술대회 논문집 Vol.- No.-
A heavy duty diesel engine(IIL) has been converted into a LPG engine using the liquid propane injection (LPj) system which is considered as a next LPG fuel supply system, since this LPi engine can generate higher power, higher efficiency, and lower emission characteristics than the existing mixer type can.<br/> A prototype heavy duty natural aspiration(NA) type K -1 engine was developed before turbo-charging system engine for convenience of LPi technical approach. The performance test results showed that the LPG engine with the LPi system have higher engine maximum power and torque by 20% approximately than the base diesel engine. Also, the torque characteristics of the engine in the low speed conditions, which is considered as an important parameter in the heavy-duty vehicle's development, was revealed very excellent.<br/>
4행정 천연가스 희박연소엔진의 성능향상에 관한 연구(Ⅱ)
방효선(H.S. Bang),한정옥(J.O. Han),조양수(Y.S. Cho),김창기(C.G. Kim),김창업(C.U. Kim),김승수(S.S.Kim) 한국자동차공학회 1995 한국자동차공학회 춘 추계 학술대회 논문집 Vol.1995 No.6_1
Lean combustion is one of the most promising method for increasing the engine efficiency and reducing the emission from SI gas engines. Due to the possibility of partial bum and misfire under lean operation, stable flame kernel formation and fast burn rate are needed to guarantee a successful subsequent combustion. Experimental data were obtained on a 4-stroke, natural gas fueled SI engine to investigate the effect of EGR rate and various high energy ignition systems on effeiciency and emissioa It has been found that there is an optimum EGR rate which gives very low NOx emission with slight decrease in efficiency and increase in UHC. Breakdown and long spark duration ignition system have been brought about the improvements in effeciency and its operational stablity under lean operating conditions. Experimental results have also displayed that the prechamber type flame-jet ingnition system extended noticeably the lean operation limit with some sacrifice in thermal efficiency due to throttling and heat losses.<br/>