• 한국자동차공학회논문집
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• 제15권6호
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• pp.30-37
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• 2007

The injection and spray characteristics of top-feed type injector was investigated under liquid phase injection fueled with liquefied petroleum gas (LPG). Different pressures and temperatures of fuel injection system were tested to identify the injection characteristics after hot soaking. MIE-scattering technique was used for verification of successful liquid phase injection after hot soaking. In case of bottom-feed type injector, the injection was accomplished at every experimental condition. In case of top-feed type injector, when the pressure of LPG was over 1.2 MPa, the injection was not executed. However, under the pressure were 1.2 MPa, the liquid phase injection after hot soaking was accomplished. The engine with top-feed type fuel injection equipment was restarted successfully after hot soaking.

• 한국자동차공학회논문집
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• 제11권1호
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• pp.42-48
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• 2003

LPG has been a broad concern of pro-environmental alternative fuel for vehicles. Recently, the new Liquid Phase LPG Injection(LPLI) system extends the limit of power of LPG engine and gives a chance to substitute LPG engine for diesel engine of heavy duty vehicles that are the main resources of air pollution in urban area. Large bore size of heavy duty LPG engine derives a serious knock problem. To find an optimal MBT conditions, it is necessary to know how the flame develops in the combustion chamber and find where the knock positions are. In this study. the ion-probe head gasket was used to estimate the knock position. Inverse operation of the ion-probe signal provides the flame developing characteristics. The further the position is from the spark plug, the later the flame arrives and the more times knock occurs. The main factor that effects knock position is inferred a flor situation of mixed gas in the combustion chamber.

• 대한기계학회논문집B
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• 제38권10호
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• pp.837-844
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• 2014

최근 자동차 제조사는 강화되는 배출가스 규제를 만족시키고 엔진 효율을 향상시키기 위해 다양한 기술을 연구하고 있다. 그 중 직접분사식 초희박 연소기술은 정밀한 연소제어를 통해 연소효율을 극대화 하고 연비를 향상시킬 수 있는 차세대 기술로 평가받고 있다. 기존 가스엔진에 초희박 직접분사기술을 적용하기 위해 기존의 MPI 엔진의 헤드를 재설계하였다. 기존 압축비10:1에서 12:1로 증가시킴으로써 이에 따른 압력선도, 열방출률, 연료소비율 등의 연소특성과 배출가스특성을 파악하였다. 압축비를 증가시킴에 따라 불안정한 연소상태로 인하여 연료소비율의 개선이 어려웠으나 탄화수소(THC)와 질소산화물(NOx)의 배출은 감소되었다.

• 한국가스학회지
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• 제20권1호
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• pp.52-61
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• 2016

액화석유가스는 환경 친화적이며 에너지 효율성과 출력성능이 뛰어나 실용성이 높고, 경쟁연료에 비해 가격 경쟁력이 우수하기 때문에 촉망받는 대체연료 중 하나로 간주된다. 스파크점화 엔진에서 직분식 기술은 엔진 체적효율을 눈에 띄게 증가시키며, 상대적으로 더 높은 연소효율이 가능한 성층급기를 이용해 엔진을 작동시킨다. 본 연구에서는 가솔린직접분사 엔진의 원리를 적용하여 가시화 시스템을 장착한 연소실을 설계하였다. 이를 통해 스파크점화직분식 LPG의 점화성과 화염전파 과정을 디지털 방식으로 기록하고 분석하였다. 이러한 연구의 결과는 스파크점화직분식 LPG 엔진의 설계 및 최적화를 위한 광범위한 기초 자료로서 기여하고자 한다.

• 한국가스학회:학술대회논문집
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• 한국가스학회 2000년도 추계학술발표회 논문집
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• pp.130-136
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• 2000

• 한국대기환경학회지
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• 제30권6호
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• pp.545-554
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• 2014

In general, odorant was added to fuel gases, such as LPG, LNG and city gas, to prevent gas poisoning, ignition, explosion, or other accident caused by fuel gases, and to enable immediate and easy detection of fuel-gas leakage by emitting an offensive smell. This study describes a study on the exhaust emissions characteristics and fuel economy of liquefied petroleum gas (LPG) vehicle using LPG fuel with new sulfur free odorant. New sulfur free odorant was added to LPG to reduce sulfur content of the LPG. Its performance and exhaust emission were compared to those of LPG with sulfur containing odorant (EM, ethyl mercaptan). Engine performance using LPG with sulfur free odorant was similar to that with sulfur-containing odorant. Exhaust emissions from the LPG vehicle with LPG including sulfur free odorant were also similar to those with LPG including sulfur containing odorant in the FTP 75 and NEDC mode. There experimental results suggest that the sulfur free odorant may substitute for the sulfur containing odorant in LPG fuel.

• 동력기계공학회지
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• 제20권2호
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• pp.32-42
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• 2016

Under part load condition of spark-ignition engine, pumping loss had great effect on engine efficiency. To reduce pumping loss, the study designed spark-ignited engines to make direct spray of gasoline to combustion chamber. In spark-ignited direct-injection engines, ignition probability is important for successful combustion and flame propagation characteristics are also different from pre-mixed combustion. This study designed a visualization testing device to study ignition probability of spark-ignited direct-injection LPG fuel and combustion flame characteristics. This visualization device consists of combustion chamber, fuel supply system, air supply system, electronic control system and data acquisition system. Ambient pressure, ambient temperature and ambient air flow velocity are important parameters on ignition probability of LPG-air mixture and flame propagation characteristics, and the study also found that sprayed LPG fuel can be directly ignited by spark-plug under proper ambient conditions. To all successful cases of ignition, the study recorded flame propagation image in digital method through ICCD camera and its flame propagation characteristics were analyzed.

• 한국에너지공학회:학술대회논문집
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• 한국에너지공학회 2003년도 춘계 학술발표회 논문집
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• pp.595-600
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• 2003

This paper presents the applicability of low caloric synthetic gas from coal gasification to a gas engine system. A commercial LPG engine is modified to use the low caloric synthetic gas from coal gasification as the gas engine fuel. The modification is focused on the fuel supplying system, which includes air flowrate adjusting orifice, gas mixer, vaporizer, preheater, regulators, and fuel tank. The electrical system and others for the alternative fuel are also redesigned and replaced. From the results of engine performance data, we have demonstrated that the engine modified by using coal gasification gas is well operated from idle to wide open throttle conditions although the engine power is somewhat reduced relative to LPG fueled engine. This paper addresses the need to determine the practical potential for such a concept and to identify further research and development efforts that may be necessary.

• 한국수소및신에너지학회논문집
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• 제12권3호
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• pp.169-176
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• 2001

The purpose of study is to obtain low-emission and high-efficiency in LPG engine with hydrogen enrichment. The test engine was named heavy-duty variable compression ratio single cylinder engine (VCSCE). The fuel supply system provides LPG/hydrogen mixtures based on same heating value. Various sensors such as crank shaft position sensor (CPS) and hall sensor supply spark timing data to ignition controller. Displacement of VCSCE is $1858.2cm^3$. VCSCE was runned 1400rpm with compression ratio 8. Spark timing was set MBT without knocking. Relative air-fuel ratio(${\lambda}$) of this work was varied between 0.76 and 1.5. As a result, i) Maximum thermal efficiency occurred at ${\lambda}$ value 1.0. It was shown that thermal efficiency was increased approximately 5% with hydrogen enrichment at same ${\lambda}$ value. ii) Engine-out carbon monoxide (CO) emissions were decreased at a great rate under LPG/hydrogen mixture fuelling. iii) Total hydrocarbon (THC) emission was much exhausted in rich zone, same as CO. But THC was exhausted a little bit more in lean zone. iv) Finally, engine-out oxides of nitrogen (NOx) was increased with ${\lambda}$ value 1.0 zone at a greater rate with hydrogen enrichment due to high adiabatic flame temperature.

• 한국산학기술학회논문지
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• 제15권3호
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• pp.1229-1235
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• 2014

LPG차량의 공기 흡입 시스템에서 먼지 입자의 대부분은 공기 청정기를 통해 제거되지만, 아주 작은 입자는 제거되지 않고 흡기계통에 축적되게 된다. 이 축적된 카본은 공회전 속도 제어와 센서신호 그리고 배출가스에 영향을 주게 된다. 또한 엔진 채터링 현상이나 자동변속기의 변속시점 불량등을 야기시킨다. 이 연구는 세척액을 사용하여 흡기계통을 세척하는 것에 관한 것이다. 워밍업된 챠량에서 흡입호스를 제거하고 세척액을 사용하여 가속시에 세척액을 흡입장치에 분사시켜 흡기계통을 세척하는 것이다. 세척액을 사용하여 스로틀 바디, ISC, 서지탱크, 흡입매니폴드, 흡기밸브, 연소실까지 세척함으로서 다음과 같은 실험결과를 얻을 수 있다. 스로틀 밸브가 정확하게 작동되어 TPS의 센서 신호 전압이 개선되었으며, 차량이 정지하는 경우 ISC 시스템은 공회전 속도 제어를 원활하게 작동하였다. 또한 일산화탄소는 약 0.15 %, 탄화수소는 약 20~100PPM으로 각각 감소되어 배기가스가 현저하게 개선되었다.