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GDI엔진의 밸브리프트 변화에 따른 연소실내 흡기유동 및 연료분포에 대한 수치 해석적 연구
김경배 ( K. B. Kim ),송미지 ( M. J. Song ),김구성 ( K. S. Kim ),강석호 ( S. H. Kang ),이영훈 ( Y. H. Lee ),이성욱 ( S. W. Lee ) 한국분무공학회 2013 한국액체미립화학회지 Vol.18 No.2
While variable value actuation or variable valve lift (VVL) is used increasingly in spark ignition (SI) engines to improve the volumetric efficiency or to reduce the pumping losses, it is necessary to understand the impact of variable value lift and timing on the in-cylinder gas motions and mixing processes. In this paper, characteristics of the in-cylinder flow and fuel distribution for various value lifts (4, 6, 8, 10mm) were simulated in a GDI engine. It is expected that the investigation will be helpful in understanding and improving GDI combustion when a VVL system is used. The CFD results showed that a increased value lift could significantly enhance the mixture and in-cylinder tumble motion because of the accelerated air flow. Also, it can be found that the fuel distribution is more affected by earlier injection (during intake process) than that of later injection (end of compression). These may contribute to an improvement in the air-fuel mixing but also to an optimization of intake and exhaust system.
한영출(Y.C.Han),김경배(K.B.Kim),오용석(Y.S.Oh),이성욱(S.W.Lee) 한국자동차공학회 1997 한국자동차공학회 춘 추계 학술대회 논문집 Vol.1997 No.11_2
To reduce the particulate matter and nitrogen oxides by diesel engine, many studies are proceeding and being accomplished practically. In this situation CNG engine has important meaning both as a clean fuel and an alternative energy. In order to present the direction and application of CNG, we simulated various operating conditions, that is, spark timing, compression ratio and fuel composition etc. Thus we try to understand how those affect<br/> performance and exhaust characteristcs. From the simulation program we proved that the optimum combustion start angle was 21° at l800rpm and fuel composition affects performance and emissions, also we could understand the formation of emission as crank angl is changed.
디젤기관의 산화촉매장치에서 저유황경유에 의한 배출가스 저감에 관한 실험적 연구
한영출(Y.C.Han),김경배(K.B.Kim),강호인(H.I.Kang),박경호(K.H.Park) 한국자동차공학회 1995 한국자동차공학회 춘 추계 학술대회 논문집 Vol.1995 No.11_2
Since environmental suspended particle concentrations have not been reduced and still over the environmental quality standards at some monitoring points in Korea. it is suspected that PM from diesel powered vehicles is one of the main causes of this problem. Therefore the strengthening of exhaust emission regulations for heavy-duty diesel vehicles is intended and many countermeasures are under development. DOC is one of the more favorable measures to reduce PM from diesel vehicles together with combustion control of engine. and DOC can effectively reduce CO and HC under actual driving conditions. In this study, we have studied the theoretical analysis on DOC. and especially the factor of sulfur content in diesel fuel affecting catalyst performance and tested the engine performance and exhaust emission in a heavy duty diesel engine equipped with oxidation catalyst.<br/>
오용석(Y.S.Oh),문기석(K.S.Moon),김경배(K.B.Kim),한영출(Y.C.Han) 한국자동차공학회 1998 한국자동차공학회 춘 추계 학술대회 논문집 Vol.1998 No.5_1
Natural gas-fueled vehicle impoes unique requirements on exhaust aftertretment system. In the CNG vehicle, exhaust hydrocarbon is mainly consist of methane. Methane conversion, which is very difficult for conventional automotive catalysts, may be required, depending on future regulatory direction. In this study, we used a transient one-dimensional model which takes into account the gas-solid heat and mass transfer, axial heat conduction, chemical reactions and the related heat release. We considered many factors affect to methane conversion, and simulated methane conversion efficiency at variable condition.<br/>
全燒方式 CNG機關의 性能豫測 프로그램 開發에 關한 硏究
한영출(Y.C.Han),엄명도(M.D.Uhm),김경배(K.B.Kim),오용석(Y.S.Oh) 한국자동차공학회 1997 한국자동차공학회 춘 추계 학술대회 논문집 Vol.1997 No.6_1
To reduce the particulate matter and nitrogen oxides by diesel engine, many studies are proceeding and being accomplished practically. In this situation CNG engine has very important meanig both as a clean fuel and as a alternative energy. In order to present the direction and application, we have to understand the property of CNG fuel and then predict the performance with using CNG engine simulation program.<br/> From the simulation program we can get some results as heavy duty vehicles could be modified to CNG engine. Also it was proved that the optimum-combustion start angle was about 11° at 2200rpm from the pressure and power diagram.<br/>
연료분무 및 연소 1 : 밸브리프트 변화에 따른 연소실내 흡기유동 및 연료분포에 대한 수치 해석적 연구
전영수 ( Y S Jeon ),송미지 ( M J Song ),이성욱 ( S W Lee ),김경배 ( K B Kim ) 한국액체미립화학회 2013 한국액체미립화학회 학술강연회 논문집 Vol.2013 No.-
While variable valve actuation or variable valve lift (VVL) is used increasingly in spark ignition (SI) engines to improve the volumetric efficiency or to reduce the pumping losses, it is necessary to understand the impact of variable valve lift and timing on the in-cylinder gas motions and mixing processes. In this paper, characteristics of the in-cylinder flow and fuel distribution for various valve lifts(4, 6, 8, 10mm) were simulated in a GDI engine. It is expected that the investigation will be helpful in understanding and improving GDI combustion when a VVL system is used. The CFD results showed that a increased valve lift could significantly enhance the mixture and in-cylinder tumble motion because of the accelerated air flow. Also, it can be found that the fuel distribution is more affected by earlier injection (during intake process) than that of later injection (end of compression). These may contribute to an improvement in the air-fuel mixing but also to an optimization of intake and exhaust system.
엄명도(M.D.Eom),한영출(Y.C.Han),김종춘(J.C.Kim),김경배(K.B.Kim) 한국자동차공학회 1996 한국자동차공학회 학술강연초록집 Vol.1996 No.10
CNG dual fuel engine for heavy duty diesel engine developed by AFS International in Canada has been equipped to a Korean bus engine and tested to compare the engine performance and the emission characteristics with the existing diesel fueled engine. The results are summarized as follows. Diesel only engine has the fuel injection timing of BTDC 17˚. The injection timing of CNG conversion engine is retarded to BTDC14° for reduction of NOx. The injection timing of BTDC 10° shows unstable engine performance and after burning at above 2000rpm, which concludes BTDC 14° as a optimum retarded timing. Performance optimization has been carried out to have engine power equivalent to or better than the diesel only engine. Smoke is decreased by 85% by Korean smoke 3 mode test. By 6 mode test CO is. increased by 313% and THC is increased by 1407%. NOx is decreased by 27%. D-13 mode of 1996 Korean regulation shows the similar result as 6 mode test. Even though THC is increased very much, it's not too serious problem since CO and HC emission of diesel engine is very little compared to gasoline engine and more than 75% of THC is CH₄.