• Journal of Energy Engineering
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• v.24 no.4
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• pp.33-41
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• 2015

Dimethyl ether (DME) can be used as a clean diesel alternative fuel due to the high cetane number and low emission, it can also be applied to automotive fuel as a blended liquefied petroleum gas (LPG) because physical properties are similar to those of LPG. In this study, feasibility test of LPG vehicle using blended DME-LPG fuel was investigated. Three types of fuel supply such as LPLi (Liquid phase LPG injection), LPGi (Liquid phase gas injection) and mixer type were selected to consider the LPG fuel-injection system. The performance characteristics of LPG vehicle were examined by using LPG and blended DME-LPG fuel in order to compare the exhaust emissions (CO, THC, $NO_X$) and fuel economy. The emissions and fuel economy of DME-LPG blend fuel were comparable to those of LPG with increasing driving distance.

• 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.8 no.6
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• pp.31-39
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• 2000

In this paper, characteristics of a port injection type LPG fuel system were investigated to adopt the system to a spark ignition engine through rig test. Engine combustion characteristics for limited conditions and the precise control method of LPG fuel supply were also studied. As a basic experiment, the effects and the relationships of parameters such as orifice area, fuel delivery pressure, fuel temperature and flow coefficient were established. From this, one dimensional compressible flow equation can be applied to control gaseous fuel flow rate by setting pressure difference between vaporizer and manifold to a certain range, for example about 1.2 bar in a naturally aspirated engine. The combustion analysis results of LPG engine were also compared with those of gasoline engine according to spark timing and load change. At part load and stoichiometric condition, the MBT spark timing of LPG fueled engine is retarded by 2$^{\circ}$ - 4$^{\circ}$CA compared to that of gasoline engine. On the contrary, the spark timing of LPG fueled engine can be advanced by 5$^{\circ}$- 10$^{\circ}$ CA at WOT, which results from higher Octane Number and burned fraction of LPG fuel compared to gasoline.

• Transactions of the Korean Society of Automotive Engineers
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• v.16 no.1
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• pp.78-85
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• 2008

The exhaust emission characteristics of a liquefied petroleum gas-di-methyl ether (LPG-DME) compression ignition engine was investigated under homogeneous charge, stratified charge and diffusion combustion conditions. LPG was used as the main fuel and injected into the combustion chamber directly. DME was used as an ignition promoter and injected into the intake port. Different LPG injection timings were tested to verify the combustion characteristics of the LPG-DME compression ignition engine. The combustion was divided into three region which are homogeneous charge, stratified charge, and diffusion combustion region according to the injection timing of LPG. The HC emission was reduced with LPG stratification. However, the carbon monoxide and particulate matter emissions were increased. The ignition timing was advanced with LPG stratification. This advance combustion was because of charge temperature and cetane number stratification with LPG.

• Transactions of the Korean Society of Automotive Engineers
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• v.17 no.1
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• pp.35-42
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• 2009

In this study, a spark ignition engine operated with LPG and DME blended fuel was studied experimentally. The effect of n-butane and propane on performance and emissions of a SI engine fuelled by LPG/DME blended fuel were examined. Stable engine operation was achieved for a wide range of engine loads with propane containing LPG/DME blended fuel compare to butane containing LPG/DME blended fuel since octane number of propane was much higher than that of butane. Also, engine output operated with propane containing blended fuel was comparable to pure LPG fuel operation. Engine output power was decreased and break specific fuel consumption (BSFC) was increased with the blended fuel since the energy content of DME was much lower than that of LPG. Considering the results of engine output power, bsfc, and exhaust emissions, the propane containing LPG/DME blended fuel could be used as an alternative fuel for LPG.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.10 no.7
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• pp.1433-1438
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• 2009

The purpose of this study is to investigate how the ignition spark timing conversion influences the engine performance of LPG/Gasoline Bi-Fuel engine. We propose the control system which can advance the ignition spark timing in LPG fuel mode more than used in gasoline fuel mode. In order to investigate the engine performance during combustion, engine performance are sampled by data acquisition system, for example cylinder pressure, pressure rise rate and heat release rate, while change of the rpm(1500, 2000) and the ignition timing advance($5^{\circ}$,$10^{\circ}$,$15^{\circ}$,$20^{\circ}$) As the result, between 1500rpm and 2000rpm, the cylinder pressure and pressure rise rate was increased when the spark ignition was advanced but pressure rise rate at $20^{\circ}$was smaller value. Also, the heat release rate at 1500rpm was increased but it was lower around $20^{\circ}$at 2000rpm.

• 한국가스학회:학술대회논문집
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• 2000.09a
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• pp.137-142
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• 2000

• Transactions of the Korean Society of Automotive Engineers
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• v.13 no.1
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• pp.28-35
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• 2005

Fuel injection rate of an injector is affected by various injection conditions such as injection duration, fuel temperature, injection pressure, and voltage in LPG liquid injection systems for either a port-fuel-injection(PFI) or a direct injection(DI) in a cylinder. Even fuel injection conditions are changed, the air-fuel ratio should be accurately controlled to educe exhaust emissions. In this study, correction factor for the fuel injection rate of an injector is derived from the density ratio and the pressure difference ratio. A voltage correction factor is researched from injection test results on an LPG liquid injection engine. A compensation method of the fuel injection rate is proposed for a fuel injection control system. The experimental results for the LPG liquid injection system in a SI-engine show that this system works well on experimental range of engine speed and load conditions. And the fuel injection rate is accurately controlled by the proposed compensation method.

• Transactions of the Korean Society of Automotive Engineers
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• v.11 no.5
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• pp.22-28
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• 2003

Flash boiling mechanism in the injector interferes with fine fuel metering in a liquid phase LPG injection engine. This study presents a mathematical model to precisely predict an injection quantity. A calibration procedure of injection quantity, which is very prompt and precise in measuring, is developed using a gas analyzer. According to this procedure, injection quantity can be obtained under various fuel compositions, temperatures and injection pressures. The release pressure of liquid phase LPG is estimated based on these experimental data. Although the release pressure is much lower than the saturation pressure, it is linearly proportional to the saturation pressure.

• 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.