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SI 엔진의 시동 및 아이들 구간에서의 점화시기에 따른 싸이클별 연소현상에 관한 실험적 연구
최성원(Seongwon Choi),최관희(Kwanhee Choi),명차리(Cha-Lee Myung),박심수(Simsoo Park) 대한기계학회 2007 대한기계학회 춘추학술대회 Vol.2007 No.5
THC(Total Hydrocarbon) emissions during cold start and warm-up phase constitute the majority of THC emissions during the FTP-75 mode. As the basic approach to improve the emission performance of Gasoline engine during transient phase, the effect of spark timing retard from MBT on THC emission characteristics is studied by engine test using a Fast response Flame Ionization Detector(FFID). A cyclic analysis of the combustion process shows that high THC emissions are produced first few cycles during the transient phase. This paper presents the results of engine performance and emission of Gasoline engine with various spark timing consequently, This paper was focused on the combustion phenomena with various spark timing during transient phase which was analyzed by Fast response Flame Ionization Detector(FFID) equipment to measure the cyclic THC emission characteristics.
하이브리드 파워트레인의 엔진 재시작 및 감속 구간에서 탄화수소 배출물 및 엔진 제어 특성 분석
온형석(Hyungseuk Ohn),유성은(Seongeun Yu),민경덕(Kyoungdoug Min) 한국자동차공학회 2008 한국자동차공학회 춘 추계 학술대회 논문집 Vol.- No.-
Stringent regulation of exhaust emission and improvement of fuel economy have become major issues in the automotive industry. Hybrid electric vehicle (HEV) can be one of the crucial alternative plans over current conventional vehicle, but they have drawbacks such as the increase of engine out total hydrocarbon (THC) emissions and the deterioration of combustion stability at frequent engine stop and restart. This study performs experimental investigation to obtain a better understanding of THC emission characteristic at engine restart and deceleration driving on a HEV powertrain of parallel motor/generator type. Using a fast response Flame Ionization Detector (FFID) and specified tool for cycle by cycle and cylinder to cylinder, the combustion and engine control characteristic was analyzed during transient state of hybrid powertrain. The experimental conditions cover variation of high voltage battery State of Charge (SoC), spark ignition timing and injected fuel mass. As an experimental result, we can unearth the effects of spark ignition timing and injected fuel mass control for combustion stability during engine restart.
INVESTIGATION OF ENGINE RESTART STABILITY AFTER IDLE STOP FOR A MILD TYPE HEV POWERTRAIN
S. E. YU,민경덕,H. S. OHN 한국자동차공학회 2013 International journal of automotive technology Vol.14 No.5
Stringent regulations on exhaust emissions and fuel economy for vehicles have become major issues in the automotive industry. Hybrid electric vehicles (HEV) are one of the crucial alternative plans to current conventional vehicles, but they have drawbacks, which include increases in total hydrocarbon (THC) emission from the engine and deterioration of the combustion stability with frequent stopping and restarting of the engine. Intake port fuel film is evaporated up during the deceleration state due to the fuel-cut. The λ (relative A/F ratio) at engine restart is lean because part of injected fuel is used to form the fuel film in the intake port. This study revealed the behavior of a fuel film in engine stop with fuel-cut and in engine restart with a simulation model. To investigate the fuel film characteristics, a simulation model was applied and validated with a single-cylinder engine. The simulation result shows that λ of at least 1.2 is required for a stable engine restart. The minimum injection quantity of the first cycle for stable combustion is suggested to be at least 240% of the steady-state idle condition.
EGR율 변화와 분사전략에 따른 저온 디젤 연소의 모드 전환 특성
한상욱(Sangwook Han),김기현(Kihyun Kim),배충식(Choongsik Bae) 한국자동차공학회 2010 한국자동차공학회 학술대회 및 전시회 Vol.2010 No.11
Combustion mode transition between low temperature diesel combustion (LTC) and conventional diesel combustion was carried out in a direct injection diesel engine by changing exhaust gas recirculation (EGR) rate with two throttles. The characteristics of combustion mode transition was analyzed based on the in-cylinder pressure and hydrocarbon (HC) emission of each cycle. In the case of mode transition from LTC to conventional diesel combustion, rapid decrease in indicated mean effective pressure (IMEP) and increase in HC emissions occurred right after throttle movement owing to air flow overshoot. On the other hand, IMEP was decreased very slowly and continuously during mode transition from conventional diesel combustion to LTC. As the EGR rate was changed slowly, IMEP fluctuation was reduced. Rapid IMEP fluctuation which occurred during mode transition by changing EGR rate was improved with application of injection strategy.