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승용 디젤 CRDI 엔진의 다단 분사가 연소 및 배기 특성에 미치는 영향
노현구(Hyun Gu Roh),이창식(Chang Sik Lee) 한국자동차공학회 2006 한국자동차공학회 춘 추계 학술대회 논문집 Vol.- No.-
This paper described the effect of the multiple injection on the stability of idle-operating and emission characteristics in a common rail direct injection diesel engine at various operating conditions. In order to investigate the influence of multiple injections in a diesel engine, the fuel injection timing was varied two pilot injections and one main injection at various conditions. The experimental apparatus is consisted of DI diesel engine with 4 cylinders, EC dynamometer, multi-stage injection control system, and exhaust emissions analyzer. The combustion pressure was measured using a piezoelectric pressure sensor installed the hole of glow plug. Detection of the crank angle of rotating engine was used for the crankshaft position sensor of the magnetic inductive type installed. The exhaust emissions from the engine were measured by using transmitted light type soot measuring instrument and NOx, HC and CO analyzer. The operating point was analyzed for the main, pilot-main, pilot-pilot-main strategy were tested. It is revealed that the combustion pressure was smoothly near the TDC and the coefficient of variations is reduced due to the effect of pilot injection. Also, NOx emissions are dramatically decreased with pilot injection because the rate of heat release. However Soot is increased at early pilot injection at main injection.
선박용 디젤 엔진에서 Pilot 분사에 대한 연소 특성 연구
이병화(Byounghwa Lee),배명직(Myungjik Bae),한동식(Dongsik Han),전충환(Chunghwan Jeon),장영준(Youngjune Chang),송주헌(Juhun Song) 대한기계학회 2008 대한기계학회 춘추학술대회 Vol.2008 No.11
Multidimensional simulation has been carried out to be clear the role of initial combustion in a marine diesel engines on reduction of NOx and soot emissions by different pilot injection condition. Pilot injection can shorten the ignition delay, thus it reduces the premixed combustion phase. Since most NOx is formed during premixed combustion, pilot injections is one of reliable strategies to reduce the NOx. The formation of NOx consists of that formed by pilot injection and that formed by main injection. The result explains that 25-3-75 among the pilot injection conditions is effective to reduce the NOx, due to optimal combination pilot injection with main injection. The purpose of this study is to explain the characteristics of combustion with pilot injection of the marine diesel engine on reduction of exhaust emissions by examining the combustion process in a cylinder and to explore the formation mechanism of NOx between pilot injection and main injection.
MFB50 값을 이용한 디젤 엔진의 주 분사시기 Closed-Loop 제어
구태형(Taehyung Koo),유성은(Seungeun Yu),최회명(Hoimyung Choi),민경덕(Kyuoungdoug Min),한경찬(Kyungchan Han),김장헌(JangHeon Kim),권순혁(Sunhyuk Kwon),조성환(Sunghwan Cho) 한국자동차공학회 2009 한국자동차공학회 학술대회 및 전시회 Vol.2009 No.11
Combustion of diesel engine is very difficult to control due to the combustion characteristic of diesel engine which is compression ignition operated by self-ignition. To improve this weak point and enhance combustion efficiency, sensitive and precise control about operation variables dleing combustion process is needed. In this research, 'Close-Loop Control' is used to accomplish accurate diesel combustion control. At first, control logic is made by ASCET program which controls main injection timing using MFB50 values. Next, experiments at steady state and transient state are fulfilled to correct MFB50 real values to target values in conventional engine. Finally, emission values from controlled mode are evaluated through comparing with uncontrolled mode in real engine operation mode.
송재은(Jaeeun Song),이정근(Jungkeun Rhee) 한국자동차공학회 2007 한국자동차공학회 춘 추계 학술대회 논문집 Vol.- No.-
As many diesel engines are utilized in middle class or compact cars, the demands for quiet and good sound quality in diesel engine also increase more and more. High combustion pressure in idle and light load acceleration mode makes it difficult to make low noise like that of gasoline engine, but the sound quality can be enhanced by introducing DOE. For the complete improvement of diesel engine sound quality, it is necessary to consider the combustion and mechanical noise. But it is thought that the reduction of the combustion noise can show us a short way to get full improvement. The most important factor to be considered in this study is to find the optimum combustion conditions without any deterioration of emission level and drivability. This paper includes the DOE method as a tool to find out the optimized combustion conditions, which is possible to realized better sound quality in idle through that method without deteriorating the important two limited conditions.