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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.
중대형 LPG 혼소엔진의 배출가스 및 연소 특성에 관한 실험적 연구
곽용환(Yonghwan Kwak),정재훈(Jae-hoon Cheong),허곤(Kon Hur),최재권(Jaekwon Chio) 한국자동차공학회 2013 한국자동차공학회 부문종합 학술대회 Vol.2013 No.5
LPG 혼소(Duel-Fuel)엔진은 LPG를 흡입공기와 예혼합시켜 연소실에 공급하고 압축행정시 분사된 경유의 착화에 의하여 연소하는 방식으로 압축착화(CI)기관과 강제점화(SI)기관의 연소특성이 동시에 일어난다. 특히 LPG는 부탄(Butane)과 프로판(Propane)이 주성분으로 혼합비율에 따라 옥탄가와 같은 연료의 특성이 변하게 된다. 본 연구에서는 Euro3 배기규제를 만족하는 중대형 상용엔진(6L급)을 혼소엔진으로 개조하여 LPG 혼소엔진의 실험을 진행하였다. LPG 혼소율이 증가함에 따라 NOx와 PM의 배출량이 감소하고 THC와 CO의 배출량은 증가하는 경향을 확인하였다. 또한, 예혼합된 LPG의 자발화 및 노킹 특성을 확인하기 위하여 부탄과 프로판 비율 및 압축비를 변경하여 시험을 진행하였다.
1.8L 급 가솔린 직접분사식 엔진의 성능 분석에 관한 연구
나동하(Dongha Na),곽용환,고춘식(Chunsik Ko),이창언(Chang-Eon Lee),김종혁(Jong-Hyuk Kim),안기환(Gi-Hwan Ahn) 한국자동차공학회 2012 한국자동차공학회 학술대회 및 전시회 Vol.2012 No.11
In this study, in order to analyze the characteristics of Gasoline Direct Injection Engines commercially available in Europe, 1.8L-class gasoline direct injection engine was chosen for the experiment, and the performance of the vehicle and its engine were analyzed. Experimental operation of the engine by chassis dynamometer are performed for a driving range of targets, and engine dynamo-experiment are performed at full load and partial load to study performance of the target engine. Experiment targets at the center of the engine cylinder head is equipped with spark plugs, and the turbocharger is applied to improve the power output. The engine was driving below 2500 rpm more than 90% of the vehicle testing time and the engine was operated at a load rate of less than 60%. In order to suppress exhaust gas temperature rise at full load, the engine drove with rich mixture at 3000 rpm and the above. BMEP was perceived by increasing the ignition timing and the two-stage fuel injection for partial load characteristics were observed above 12 bar of the BMEP. In addition, the combustion analysis was performed in this study. Excess air rate and emissions reduction efficiency were measured to characterize the test engine.
기계식 디젤엔진의 디젤-천연가스 혼소화를 통한 디젤 대체율 향상 연구
심주현(JuHyen Sim),곽용환(Yonghwan Kwak),고춘식(Chunsik Ko),이욱재(Okjae Lee),이상민(Sangmin Lee),이창언(Chang-Eon Lee) 한국자동차공학회 2012 한국자동차공학회 학술대회 및 전시회 Vol.2012 No.11
An experimental study was performed to provide the effect of PM reduction and the improvement of diesel alternative ratio utilizing diesel-natural gas dual-fuel combustion mode in a retrofit 3.4-liter diesel engine. In order to achieve the same power as the original diesel engine, engine control unit (ECU) of the dual-fuel engine was calibrated. During this calibration, the amount of diesel fuel injection was fixed same as the amount in the idle state for all engine load conditions and liquefied natural gas (LNG) fuel injection was adjusted to increase power based on the power in idling state. LNG fuel was injected by a single point injection at the inlet of intake air manifold. As a result, diesel alternative ratio was improved in overall through making up the characteristic of lower diesel fuel consumption in comparison with mechanical diesel engine. Diesel alternative ratio was calculated from the experimental data acquired from full load test. It was found that the maximum value of diesel alternative ratio was about 96%. Finally PM emission experiment was performed in C1-8 mode cycle and it was shown PM emission was extremely reduced down to 7.42*10<SUP>-7</SUP> g/kWh comparing with mechanical diesel engine. From these results we believe our dual-fuel engine could meet Tier-4 regulations.