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디젤 엔진 실린더 헤드의 워터 재킷 표면의 온도가 침식 및 부식에 미치는 영향
황준식(Joonsik Hwang),김동훈(Donghoon Kim),한상욱(Sangwook Han),배충식(Choongsik Bae),홍재웅(Jaewoong Hong),윤수환(Soohwan Yoon) 한국자동차공학회 2012 한국자동차공학회 학술대회 및 전시회 Vol.2012 No.11
In recent years, there have been reports of erosion on cylinder head water jacket from several vehicle manufacturers. The degree of erosion may cause deterioration in the cooling capabilities and serious damage to the engine. The reason for the erosion is widely known as repeating formation and collapse of bubble caused by temperature difference between coolant and surface temperature. Therefore, in this study, the erosion and corrosion behavior of water jacket was investigated with rectangular specimen under 3 different specimen temperature conditions (170℃, 200℃, 230℃). The experiment was conducted in test bench which provide the similar conditions as diesel engine cylinder head. The surface of specimen was visualized with SEM-images after 25hours of operation in the test bench and the weight was measured with precise mass scale. The surface composition of specimen which was exposed to coolant during the experiment was quantified with energy dispersive spectroscopy (EDS) analysis every 25hours in the experiment. From the results, the greatest differential rate of mass reductions were observed with highest surface temperature (230℃) experiment. The composition of aluminum and silicon on the specimen did not have clearly consistent tendency.
폐식용유 바이오디젤과 디젤을 적용한 대형 디젤 엔진의 입자상 물질 특성 비교
황준식(Joonsik Hwang),배충식(Choongsik Bae) 한국연소학회 2014 KOSCOSYMPOSIUM논문집 Vol.2014 No.5
The characteristics of particulate matters (PM) from waste cooking oil (WCO) biodiesel and diesel were experimentally investigated in a heavy duty diesel engine. The tests were performed in conventional and low temperature combustion mode (LTC). The morphology of soot particles was analyzed using high resolution transmission electron microscopy (TEM). The elemental analaysis and thermogravimetric analysis (TGA) were also conducted to study chemical composition of soot particles. The results showed that PM from LTC was comprised of smaller primary particles containing more volatile fractions than conventional combustion mode. In term of fuels, WCO biodiesel soot particles showed smaller primary particle diameter with higher portion of oxygen and hydrogen than diesel soot.
폐식용유 바이오디젤을 이용한 압축착화엔진의 저부하 영역에서 연료의 분사 압력과 분사 시기가 연소 및 배기특성에 미치는 영향
황준식(Joonsik Hwang),정용진(Yongjin Jung),배충식(Choongsik Bae) 한국연소학회 2012 KOSCOSYMPOSIUM논문집 Vol.- No.45
In this study, the combustion and emission characteristics of waste cooking oil biodiesel was investigated. The fuel was injected from 5 CAD (Crank angle degree) ATDC (After top dead center) to ?60 CAD ATDC by 5 CAD with 800 bar and 1600 bar injection pressure. Generally, the hydrocarbon, carbon monoxide and smoke emissions from biodiesel fuel were lower than the emission levels of diesel fuel. However, the emission characteristic of biodiesel got worse than diesel when the fuel was injected earlier than ?30 CAD ATDC. NOx emission from biodeisel was higher than diesel fuel in all experimental conditions.