• Journal of the Korean Institute of Gas
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• v.19 no.6
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• pp.22-27
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• 2015

Hydrogen features highest energy density per mass and is expected to be desirable as a fuel of HALE(High altitude long endurance) UAV(Unmanned aerial vehicle). A reciprocating internal combustion engine is known to be a reliable and economic power source for this kind of UAV. Therefore, the combination of hydrogen and engine is worth of doing research. Test bench with 2.4L Spark-Ignited engine was prepared for the experiment in which start and combustion characteristics at idle condition were examined in this study. Stable hydrogen supply system and a universal ECU(Engine control unit) were also utilized for the test engine. Equivalence ratio and spark timings at idle operation were investigated and compared to the data of gasoline engine. The results will be a starting point for full-scale research of hydrogen engine for HALE UAV.

• Proceedings of the Korea Air Pollution Research Association Conference
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• 2009.10a
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• pp.116-117
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• 2009

• LP가스
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• v.21 no.6
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• pp.10-15
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• 2009

21세기의 이슈 중 가장 주목받고 있는 것은 '녹색성장'입니다. 정부 역시 '저탄소 녹생성장'을 향후 60년 비전으로 제시하여 에너지 위기와 경제위기를 동시에 타개해 나가겠다고 선포하였습니다. 이에 따라 환경부에서는 저탄소 녹색성장의 효율적 추진을 위해 지자체 기후변화대응 강화, 탄소포인트제 실시, 폐기물 에너지 자원화, 저탄소형 소비 생산 문화 확산, 온실가스감축 실천프로그램, 저탄소 자동차 보급 확대 등 10대 중점과제를 선정하여 단계별로 추진 중입니다. 지금부터는 고유가 시대에 저렴한 연료비로 관심을 바도 있는 LPG차량(완성차, 엔진개조차량 포함)의 연비 특성에 대해 살펴보겠습니다.

• Journal of the korean Society of Automotive Engineers
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• v.17 no.3
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• pp.1-10
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• 1995

디젤자동차로부터 배출되는 입자상 물질은 건강에 나쁘기 때문에 1980년에 미국환경보호청(EPA)에 의해서 디젤승용차 및 디젤 소형트럭의 입자상 물질 규제가 제정되고 이의 대책으로서 엔진 개조와 병행해서 후처리장치, 주로 입자상 물질 트랩 시스템의 개발이 미국, 유럽, 일본에서 시작되었다. 트랩시스템은 아직 개발단계에 있고 여러가지로 개발과 개량이 계속되고 있다. 여기에서는 그들의 개발의 동향을 소개한다. 1. 입자상 물질 트랩 시스템. 2. 입자상 물질 트랩 시스템의 개발 상황.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.28 no.10
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• pp.1178-1183
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• 2004

The purpose of this study was to investigate the influence of compression ratio on engine performance in a LPG(Liquefied Petroleum Gas) engine converted from a diesel engine. In ordor to determine the ideal compression ratio, a variable compression ratio 4-cylinder engine was developed. Retrofitting a diesel engine into a LPG engine is technically very complicated compared to a gasoline to LPG conversion. The cylinder head and the piston crown were modified to bum LPG in the engine. Compression ratios were increased from 8 to 10 in an increment of 0.5, the ignition timing was controlled to be at MBT(Minimum Spark Advance for Best Torque) for each case.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.35 no.11
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• pp.1163-1168
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• 2011

Compared with the spark-ignition gasoline engine, the compression-ignition diesel engine has reduced fuel consumption due to its higher thermal efficiency. In addition, this reduction in the fuel consumption also leads to a reduction in $CO_2$ emission. Diesel engines do not require spark-ignition systems, which makes them less technically complex. Thus, diesel engines are very suitable target engines for using biofuels with high cetane numbers. In this study, the spray characteristics of biofuels such as vegetable jatropha oil and soybean oil were analyzed and compared with those of diesel oil. The injection pressures and blend ratios of jatropha oil and diesel oil (BD3, BD5, and BD20) were used as the main parameters. The injection pressures were set to 500, 1000, 1500, and 1600 bar. The injection duration was set to $500{\mu}s$. Consequently, it was found that there is no significant difference in the characteristics of the spray behavior (spray angle) in response to changes in the blend ratio of the biodiesel or changes in the injection pressure. However, at higher injection pressures, the spray angle decreased slightly.

• Journal of the Korean Institute of Gas
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• v.19 no.2
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• pp.66-73
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• 2015

The amount and quality of waste heat from a gas engine which is modified from an automobile gasoline engine is analyzed. Exhaust temperature is $573.8^{\circ}C$ and engine cooling water exit temperature is $85.7^{\circ}C$. The amount of waste heat of engine cooling water is double compared to that of exhaust gas. Organic Rankine cycle (ORC) system is designed for two different waste heat source of engine cooling water and engine exhaust and is thermodynamically analyzed.

• Journal of the Korean Society of Propulsion Engineers
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• v.23 no.5
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• pp.1-9
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• 2019

Infrared signal and exhaust gas temperature distribution with bypass ratio were measured using a micro turbojet engine. Micro turbojet engine was modified to simulate the turbofan engine behaviour. Core flow was simulated using the jet flow of the micro turbojet engine, and high-pressure air was supplied to its external duct to simulate bypass flow. The effects of bypass ratios (0.5, 1.0, and 1.4) were examined. The experimental results indicate that the infrared signal decreases as the bypass ratio increases. And also gas temperature decreases with bypass ratios. Additionally, Schlieren visualization of the exhaust gas plume was conducted. From the exhaust gas temperature distribution and Schlieren images, the structure of jet plume with various bypass ratios was understood.

• Journal of Advanced Marine Engineering and Technology
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• v.35 no.4
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• pp.460-467
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• 2011

Cavitation phenomena during the spill process of the Bosch type fuel injection pump for medium-speed diesel engine were investigated by optical observations. Typically, these phenomena can cause a surface damage with material removal or round-off at the plunger and barrel port etc., and may shorten their expected life time. The images, which were recorded with high speed CCD camera and borescope, show that the plunger damage is mainly affected by fountain-like cavitation generated before the end of delivery. And the damages of barrel port and deflector are caused by jet-type cavitation generated after end of delivery.

• Transactions of the Korean Society of Automotive Engineers
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• v.14 no.6
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• pp.73-81
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• 2006

A commercial diesel engine was converted into a dedicated natural gas engine to reduce the exhaust emissions in a retrofit of a diesel-fueled vehicle. The cylinder head and piston were remodeled into engine parts suited for a spark ignition engine using natural gas. The remodeling of the combustion chamber changed the compression ratio from 21.5 to 10.5. A multi-point port injection(MPI) system for a dedicated natural gas engine was also adopted to increase the engine power and torque through improved volumetric efficiency, to allow a rapid engine response to changes in throttle position, and to control the precise equivalence ratio during cold-start and engine warm-up. The performance and exhaust emissions of the retrofitted natural gas engine after remodeling a diesel engine are investigated. The emissions of the retrofitted natural gas engine were low enough to satisfy the limits for a transitional low emission vehicle(TLEV) in Korea. We concluded that a diesel engine can be effectively converted into a dedicated natural gas engine without any deterioration in engine performance or exhaust emissions.