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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.
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.
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.
디젤-에탄올 혼합연료의 다단 분사가 디젤 엔진 성능 및 배기물 특성에 미치는 영향
노현구(Hyun Gu Roh),이두진(Doo Jin Lee),성기안(Kian Sung),이창식(Chang Sik Lee) 한국자동차공학회 2011 한국자동차공학회 부문종합 학술대회 Vol.2011 No.5
This study is to investigate the effect of the multiple injections on the emission characteristics and engine performance of ethanol blended diesel fuel in a 4 cylinder light-duty diesel engine. In order to perform the influence of multiple injections and diesel-ethanol blended fuel in a passenger diesel engine, the injection strategy was controlled with pilot injection, double pilot injections, and one main injection at various experimental conditions. The experimental apparatus is consisted of DI diesel engine, EC dynamometer, multi-stage injection control system, and exhaust emissions analyzer. The results showed that diesel-ethanol blended fuel had longer ignition delay than those of diesel fuel. Also the effects of diesel-ethanol blended fuel on the exhaust emissions such as NOX and soot emissions were discussed under the various test conditions.
실린더 직접분사식 디젤엔진에서 바이오디젤 혼합연료의 연소 및 배기특성
이동곤(Donggon Lee),노현구(Hyun Gu Roh),최석천(Seuk Cheun Choi),이창식(Chang Sik Lee) 대한기계학회 2011 大韓機械學會論文集B Vol.35 No.2
본 연구는 4실린더 커먼레일 디젤엔진에 바이오디젤 혼합 디젤연료를 적용하였을 경우 엔진의 연소특성과 배출물 저감효과를 실험적으로 구한 것이다. 실험 연료는 바이오디젤 20%와 디젤연료 80%(체적분율)를 혼합한 BD20과 저유황디젤연료(ULSD)를 사용하였으며, 연료분사압과 엔진회전수를 변수로하여 실험을 수행하였다. 실험결과 B20과 ULSD 모두 연료분사압력이 증가함에 따라 NOX 배출농도는 증가하고, Soot 배출량은 감소하는 경향을 나타내었다. 특히 BD20의 경우 ULSD와 비교하여 NOX 배출농도는 다소 증가하였으나, Soot 배출량은 현저하게 감소하였다. 또한, 회전속도가 1000rpm에서 2000rpm으로 증가함에 따라 NOX 배출농도는 감소하고, Soot 배출량은 낮은 분사압력에서 현저히 증가하는 경향을 나타내었다. This paper describes the effects of biodiesel blended fuel on the engine combustion and emission characteristics in a four cylinder CRDI(Common-rail direct injection) diesel engine. In this work, the biodiesel-diesel blended fuel(20% of biodiesel and 80% of ULSD(ultra low sulfur diesel) by volume ratio, BD20) and ULSD fuel are used under the various injection pressures and engine speeds. The experimental results of BD20 and ULSD fuel show that NOX emissions were increased and soot emissions were decreased with the increase of injection pressure. In particular, NOX emissions were slightly increased for the BD20 fuel, however, soot emissions were significantly reduced compared to the ULSD fuel. When the engine speed is increased from 1000rpm to 2000rpm, NOX emissions are decreased at all tested conditions, and soot emissions are largely increased at lower injection pressure.