• Transactions of the Korean Society of Automotive Engineers
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• v.15 no.6
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• pp.23-29
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• 2007

In Korea, the number of LPG vehicles is increasing continuously because LPG is cheaper than Gasoline. Also in Europe, the CNG fuel is a good solution to meet $CO_2$ regulation. In order to use LPG/CNG fuel, new EMS ECU must be developed for every type of vehicles and it requires huge development cost. In order to reduce development cost and time, SIEMENS VDO has developed an Interface Box. It supports EMS ECU in the car and manages LPG/CNG fuel injection system. Basically the Interface box can be used with any kind of EMS ECU. The Interface Box controls LPG/CNG injector through the injection command of gasoline EMS ECU. It calculates required amount of based on the fuel temperature and pressure and sends feedback signal to ECU for fuel correction. Also, it controls LPG/CNG specific actuator such a Shut off valves and LPG switch inputs.

• Transactions of the Korean Society of Automotive Engineers
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• v.11 no.4
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• pp.15-21
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• 2003

LPG is considered as one of the most prominent alternative automotive fuels in worldwide. However, conventional mixer system can not meet the emission regulations as the mileage accumulation increased. Recently, much attention is focused on the development of LPG liquid injection fuel systems to increase the engine performance and reduce the exhaust emissions. This study evaluates the LPLi(Liquid Phase LPG injection) engine performance and exhaust emission characteristics using a 3.0 liter LPG engine. The fuel supply system and engine management system were changed from FBM into LPLi to control the precise mixture ratio and optimized spark advance.

• Journal of ILASS-Korea
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• v.27 no.4
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• pp.211-218
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• 2022

Recent vehicle regulations have become increasingly stringent in order to reduce greenhouse gases. Then not only movement to replace internal combustion engine vehicles with hybrid vehicles, but also studies of replacing internal combustion engine fuels with low-pollution fuels are increasing. In this study, the characteristics of a vehicle with LPG fuel engine and mild hybrid system is investigated. To avoid shortage of maximum power on LPG engine, a direct injection system of LPG is applied. In addition, P0 mild hybrid system is adopted to enhence the efficiency of the vehicle. The vehicle model is developed in order to predict fuel economy and CO2 emission of LPDi MHEV.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.32 no.3
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• pp.216-223
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• 2008

Reburning is a useful technology in reducing nitric oxide through injection of a secondary hydrocarbon fuel. In this paper, an experimental study has been conducted to evaluate the effect of fuel lean reburning on $NO_X/CO$ reduction in LPG flame. Experiments were performed in flames stabilized by a co-flow swirl burner, which was mounted at the bottom of the furnace. Tests were conducted using LPG gas as the reburn fuel as well as the main fuel. The effects of reburn fuel fraction and injection location of the reburn fuel were studied when the fuel lean reburning system was applied. The paper reports data on flue gas emissions and temperature distribution in the furnace for a wide range of experimental conditions. At steady state, temperature distribution and emission formation in the furnace have been measured and compared. This paper makes clear that in order to decrease both NOx and CO concentrations in the exhaust when the fuel lean reburning system was adapted, it is important that the control of some factors such as initial equivalence ratio, reburn fuel fraction and temperature of reburn fuel injection region. Also it shows the fuel lean reburning is also effective method to reduce NOx as much as reburning.

• Transactions of the Korean Society of Automotive Engineers
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• v.24 no.6
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• pp.619-626
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• 2016

The new 1.4 L turbocharged LPG direct injection (T-LPDI) engine is presented in this paper to improve the fuel efficiency of the vehicles installed with the 2.0 L LPG port fuel injection (LPI) engine, while maintaining the performance as a downsizing concept for the new engine platform development. Firstly, the return type high pressure LPG fuel supply system is designed and mounted in the new 1.4 L T-LPDI engine. As a result, this new engine shows a much better WOT performance and approximately 8 % of improved fuel economy level, as compared to the 2.0 L LPI vehicle. Secondly, the LPDI engine specific optimized design for high pressure fuel components and fuel injection control strategies are proposed and evaluated in order to overcome the restartability problem in a heat-soaked condition called the vapor lock phenomenon. Consequently, these experimental results illustrate a great potential for the developed 1.4 L T-LPDI engine as a possible substitute for the 2.0 L LPI engine.

• Proceedings of the KSME Conference
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• 2008.11b
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• pp.2904-2909
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• 2008

The liquid phase LPG injection (LPLi) system (the 3rd generation technology) has been considered as one of the more promising fuel supply systems for LPG vehicles. To investigate the characteristics of LPG residue in LPLi system, various rubbers were reacted with LPG fuels. The results showed that the residue of a cover rubber in a fuel pump after test increased 10 times higher than that before test. Furthermore, the amount of sulfur, nitrogen species which are considered as main sources in deposit formation in the LPLi fuel injector were also found to be higher than that in original LPG fuel. And these residues made the core parts of LPLi injector such as a neddle and a nozzle, partially worn, which eventually causes a leakage in LPLi injectors.

• 연구논문집
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• s.33
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• pp.5-16
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• 2003

Fuel distribution, combustion, and flame propagation characteristics of heavy duty engine with the liquid phase LPG injection(LPLI) were studied in a single cylinder engine. Optically accessible single cylinder engine and laser diagnostics system were built for quantifying fuel concentration by acetone PLIF(planar laser induced fluorescence) measurements. In case of Otto cycle engine with large bore size, the engine knock and thermal stress of exhaust manifold are so critical that lean burn operation is needed to reduce the problems. It is generally known that fuel stratification is one of the key technologies to extend the lean misfire limit. The formation of rich mixture in the spark plug vicinity was achieved by open valve injection. With higher swirl strength(Rs=3.4) and open valve injection, the cloud of fuel followed the flow direction and the radial air/fuel mixing was limited by strong swirl flow. It was expected that axial stratification was maintained with open-valve injection if the radial component of the swirling motion was stronger than the axial components. The axial fuel stratification and concentration were sensitive to fuel injection timing in case of Rs=3.4 while those were relatively independent of the injection timing in case of Rs2.3. Thus, strong swirl flow could promote desirable axial fuel stratification and, in result, may make flame propagation stable in the early stage of combustion.

• Journal of ILASS-Korea
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• v.14 no.4
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• pp.147-152
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• 2009

Since a liquid-phase LPG injection system allows accurate control of fuel injection and increase in volumetric efficiency, it has advantages in achieving higher engine power and lower emissions compared to the mixer type LPG supplying system. However, this system also leads to an unexpected event called icing phenomenon which occurs when moisture in the air near the injector freezes and becomes frost around the nozzle hole due to extraction of heat from surrounding caused by instant fuel vaporization. As a result, it becomes difficult to control air/fuel ratio in engine operation, inducing exacerbation of engine performance and HC emission. One effort to mitigate icing phenomenon is to attach anti-icing injection tip in the end of nozzle. Therefore, in this study, the effect of engine operation parameters as well as surrounding conditions on icing phenomenon was investigated in a bench test rig with commercially-used anti-icing injection tips. The test results show that considerable ice was deposited on the surface near the nozzle hole of the anti-icing tip in low rpm and low load operating conditions in ambient air condition. This is because acceleration of detachment of deposited ice from the tip surface was induced in high load, high rpm conditions, resulting in decrease in frost accumulation. The results of the bench testing also demonstrate that little or no ice was formed at surrounding temperature below a freezing point since the absolute amount of moisture contained in the intake air is too small in such a low temperature.

• International Journal of Automotive Technology
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• v.5 no.4
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• pp.239-245
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• 2004

It has been recognized that alternative fuels such as Liquid Petroleum Gas (LPG) show less polluting combustion characteristics than diesel fuel. Furthermore, engine performance is expected to be nearly equal to that of the diesel engine if direct-injection stratified-charge combustion of the LPG can be adopted in the spark-ignition engine. However, spray characteristics of LPG are quite different from those of diesel fuel. understanding the spray characteristics of LPG and evaporating processes are very important for developing efficient and low emission LPG engines optimized in fuel injection control and combustion processes. In this study, the LPG spray characteristics and evaporating processes were investigated using the Schlieren and Mie scattering optical system and single-hole injectors in a constant volume chamber. The results show that the mixture moves along the impingement wall that reproduced the piston bowl and reaches in ignition spark plug. LPG spray receives more influence of ambient pressure and temperature significantly than that of n-dodecane spray.

• Journal of ILASS-Korea
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• v.10 no.4
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• pp.8-15
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• 2005

The use of clean gaseous fuels for the purpose of high efficiency and low emission in automotive engines has tendency to increase in order to meet the reinforcing emission regulations and to efficiently utilize limited natural resources. Automotive companies developed and commercialized a LPG liquid injection system, which is mounted on LPLi(Liquid Phase LPG Injection) engines and vehicles based on this research trend. This research examines the biggest problem in LPLi engine, that is, the leakage characteristics of low viscosity LPG fuel according to the injector design variables. This study is also aimed to improve the performance of fuel-leakage in LPLi engine through the addition of a lubrication improver in HFRR(High Frequency Reciprocating Rig) facility. The needle displacement and the spring displacement of an LPLi injector are found to be already optimized. The possibility of a maximum of 70% leakage reduction compared to a conventional case, is verified when 1000ppm of a lubrication improvement material is added and 40% increase of a injector spring constant (K) is applied.