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승용차 디젤엔진의 연료 다단 분사가 연소 안정 및 배출물 특성에 미치는 영향
노현구,이창식,Roh, Hyun-Gu,Lee, Chang-Sik 한국자동차공학회 2007 한국 자동차공학회논문집 Vol.15 No.4
This paper described the effect of the multiple injections on the stability of combustion and emission characteristics in a 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 one main injection and two pilot injections at various conditions. The experimental apparatus consisted of DI diesel engine with four cylinders, EC dynamometer, multi-stage injection control system, and exhaust emissions analyzer. The combustion and emission characteristics were analyzed for the main, pilot-main injection, pilot-pilot-main injection strategies. It is revealed that the combustion pressure was smoothly near the top dead center and the coefficient of variations is reduced due to the effect of pilot injection. Also, $NO_x$ emissions are dramatically decreased with pilot injection because the decrease of rate of heat release. However, the soot is increased at early pilot injection and main injection.
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.
노현구(Roh, Hyun Gu),吳次芳(Wu, Ci Fang),方明(Fang, Ming),정재호(Chung, Jae Ho) 한국부동산학회 2011 不動産學報 Vol.47 No.-
1. CONTENTS (1) RESEARCH OBJECTIVES This paper aims to examine the privatization of Chinese public housing during commercial housing process after reform and open since 1978. Also, this study is to explore and analysis uneven wealth distribution caused by the privatization of Chinese public housing. (2) RESEARCH METHOD This study was performed through Chinese literature investigation and consultation with relevant experts. (3) RESEARCH RESULTS China started to sell public housing to their employees by very cheap price through private housing reform after 1982. As of 2007, Shanghai has been sold 1.73 million public housings to employees, ninety-six percent of public housings were privatized. However, relative to commercial housing, the price of public housing was 2.78 times cheaper than it in 2000. By 2009, it was 10 times cheaper than commercial housing. 2. RESULTS Throughout the welfare housing to the currency housing, the employees with workplace have continued to benefit from housing reform, which exacerbated rich-poor polarization.
운행차 배출가스 정밀검사 결과를 이용한 가솔린 차량에 대한 배출가스 특성 분석
노현구 ( Hyun Gu Roh ) 한국액체미립화학회 2018 한국액체미립화학회지 Vol.23 No.3
In this study, the following conclusions could be obtained from the analysis of emissions contribution rates and features for contaminated emissions by 13,456 gasoline vehicles passed in the vehicle load test (ASM-idle) under the inspection year 2013 to 2017. It was confirmed that the contamination of the CO, HC, NOx by the displacement is reduced on over 3L engine. As a result of comparing the exhaust gas in the low speed idle mode and the AS2525 mode, the exhaust gas in the low speed idle mode was measured high. It is estimated that if ISG function is applied, emissions from idle condition will be reduced. NOx emissions were reduced when the engine power was above 200HP. It has been confirmed that the amount of exhaust emissions are significantly reduced for vehicles manufactured after 2004. As a result of analyzing the exhaust gas according to the season, it is judged that there is a correlation between HC and NOx according to the ambient temperature. The concentration of exhaust emission in vehicles with high accumulated distance increases, which is considered to be the result of aging of the vehicle.
승용 디젤 CRDI 엔진의 다단 분사 및 분사압력이 연소 및 배기 특성에 미치는 영향
노현구(Hyungu Roh),전학식(Haksik Jeon),이창식(Changsik Lee) 한국자동차공학회 2007 한국자동차공학회 춘 추계 학술대회 논문집 Vol.- No.-
This paper describes the effect of the multiple injection and injection pressure on the combustion and emission characteristics in a CRDI diesel engine at various operating conditions. In order to investigate the influence of multiple injections and injection pressure in a diesel engine, the fuel injection timing was varied double pilot injections and main injection at TDC. The experimental apparatus is consisted of DI diesel engine with 4 cylinders, EC dynamometer, multi-stage injection and injection pressure control system, and exhaust emissions analyzer. The combustion and emission characteristics are investigated of various injection strategies such as analyzed for the main, one pilot-main, double pilot-main strategy. The results showed that the average of peak combustion pressure is increased with the increase of injection pressure. Also, double pilot injection has a great effect on reducing NOx emissions because the decrease of peak heat release rates. However soot is increased at the double pilot injection compared to single injection. Based on this result, it showed that the combustion and emission characteristics can be improved as the pilot injection is retarded.
GDI 엔진의 분할 분사가 아이들 연소 안정 및 배출물 특성에 미치는 영향
노현구 ( H G Roh ) 한국분무공학회 2014 한국액체미립화학회지 Vol.19 No.4
This paper described the effect of split injections on the stability of combustion and emission characteristics in a directinjection gasoline engine at various operating conditions. In order to investigate the influence of direct injection gasoline engine, the fuel injection timing was varied direct fuel injection at various fuel pressure. The experimental apparatus consisted of GDI engine with 4 cylinder, EC dynamometer, injection control system, and exhaust emissions analyzer. The emission and combustion characteristics were analyzed for the fuel injection timing and fuel injection pressure strategies. It is revealed that CO and HC emissions are dramatically decreased at advanced injection timing. Also, engine performance is increased atincrease fuel injection pressure.
승용 디젤 엔진에서 분사 전략이 배출 가스 및 엔진 성능에 미치는 영향에 관한 연구
노현구(Hyun Gu Roh),이두진(Doo Jin Lee),이창식(Chang Sik Lee) 한국자동차공학회 2011 한국 자동차공학회논문집 Vol.19 No.3
This paper described the effect of the multiple injections on the emission characteristics and combustion stability in a common rail diesel engine. In order to investigate the influence of multiple injections in a passenger car diesel engine, the injection strategy was varied with pilot injection, post injection and one main injection at various conditions. Based on the experimental results, the combustion and emissions characteristics were analyzed for the various injection strategies such as main, pilot-main, double-pilot-main, double-pilot-main-post injection strategy. It is revealed that the NOX, HC and CO emissions are reduced by double pilot and post injection at medium load, however, soot emission is increased. Also, in the case of multiple injection, the combustion pressure is increased smoothly near the TDC and the coefficient of variation and fuel consumptions are decreased.