• International Journal of Automotive Technology
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• v.7 no.4
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• pp.407-413
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• 2006

The liquefied petroleum gas(LPG), mixture of propane and butane, has the potential to reduce toxic hydrocarbon emissions and inhibit ozone formation due to its chemical composition. Conventional mixer systems, however, have problems in meeting the future lower emission standards because of the difficulty in controlling air-fuel ratio precisely according to mileage tar accumulation. Liquid Phase LPG injection(LPLi) system has several advantages in more precise fuel metering and higher engine performance than those of the conventional mixer type. On the other hands, leakage problem of LPLi system at the injector tip is a main obstacle for meeting more stringent future emission regulations because these phenomena might cause excessive amount of THC emission during cold and hot restart phase. The main focus of this paper is the development of a leaked fuel recirculation system, which can eliminate the leaked fuel at the intake system with the activated carbon canister. Leaked fuel level was evaluated by using a fast response THC analyzer and gas chromatography. The result shows that THC concentration during cold and hot restart stage decreases by over 60%, and recirculation system is an effective method to meet the SULEV standard of the LPLi engine.

• International Journal of Automotive Technology
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• v.2 no.4
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• pp.147-155
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• 2001

Analysis of the thermodynamic cycle of IC engine from the point of view of economy and emissions was carried out. From this analysis potential capability of engine development was derived. This potential capability is lean-burn engine, fuelled with homogeneous mixture with $\lambda \geq$ 1.4. Several different modes of fuelling were proposed and tested on one-cylinder test engine from the point of view of extending lean operating limit of the engine, emissions and fuel economy. Among them were: fuelling with evaporated preheated gasoline, with gas (LPG evaporated) and with liquid butane. From these modes, fuelling with liquid butane injected to inlet port was selected and finally tested. This novel system of fuelling offered better than standard engine performances and emissions at lean operating limit. These results were validated on full-scale two-cylinder engine.

• Transactions of the Korean Society of Automotive Engineers
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• v.12 no.2
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• pp.39-44
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• 2004

As air pollution has become an important issue across the world, studies of clean fuel are on going to reduce combustion emissions. One example is development of the LPLi(Liquefied Phase LPG injection) engine. Some problems are occurred during development. One of the problems is icing phenomenon at injector tip due to evaporation potential heat when liquid LPG is injected. If the Icing is raised at injector tip or injector inserting hole, it disturbs fuel injection. And if the ice particles are inducted into cylinder, it brings problems associated with control of emission and air/fuel ratio. In order to solve the problems, a rig system was set up and observed Icing of injector tip. Engine test was carried out for visualization of injector tip icing and its effects on combustion and emissions.

• Journal of the Korean Institute of Gas
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• v.16 no.2
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• pp.38-44
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• 2012

In recent years, the need for more fuel-efficient and lower-emission vehicles has driven the technical development of alternative fuels such as LPi (Liquid phase LPG injection) which uses pump for the high pressure supply of liquid LPG fuel and is able to meet the limits of better emission levels while it has an advantage of higher power. Although it has the advantage of power and lower emission levels, the characteristics of LPG, such as high vapor pressure, lower viscosity and surface tension than gasoline fuels makes it difficult design system. Therefore most fuel pumps and injectors are imported. In the present study, in order to domestically develop LPG injector which guarantees flow rates and optimal operation, the experimental investigation on leakage and flow rate characteristics of developed prototype injector was carried out at the bench test rig for developed injector.

• Transactions of the Korean Society of Automotive Engineers
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• v.10 no.5
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• pp.23-28
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• 2002

As the interest on the air pollution is gradually rising up at home and abroad, automotive industries have been working on the exhaust emission reduction from vehicles through a lot of approaches, which consist of new engine design, innovative aftertreatment systems, and using clean fuels. Methanol, ethanol, LNG, LPG, H2, reformulated gasoline are generally recognized as the clean fuel. Since the low price policy of government on LPG has expanded its vehicle market recently, there is concern of the exhaust emission of LPG vehicle. In this paper, we studied the value of LPG fuel as a clean fuel by comparing the results of the exhaust emission from LPG and Gasoline fueled vehicles, and discussed its limitation of LPG vehicle with mixer type as a fuel supply system. FTIR was used to understand the difference of exhaust emission components of LPG and Gasoline fueled vehicles.

• 제어로봇시스템학회:학술대회논문집
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• 2002.10a
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• pp.68.3-68
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• 2002

This paper presents a neural network approach to control exhaust gas recirculation(EGR) in a Liquefied Petroleum Gas(LPG) engine. In order to meet Increasingly stringent automotive exhaust emission regulations, alternative fuels such as LPG engines have been developed in many countries. HC&CO emissions of LPG engines can be easily reduced through air-fuel ratio control, but the control effect on NOx reduction is not good enough. Consequently EGR system is introduced to achieve a significant reduction in NOx emissions. Conventional EGR control uses the mapping method. The calibration time is long and the work is complex when adopting this mapping method. However neural networks are suitable f...

• Transactions of the Korean Society of Automotive Engineers
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• v.10 no.4
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• pp.77-84
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• 2002

For the purpose of obtaining a fundamental data which is needed to develope the port injection type charged LPLi engine system, we manufactured intake port injection system of liquid charging LPG and modified heavy duty single cylinder LPLi engine from heavy duty diesel engine. Engine output and emission characteristics were analyzed under variable air/fuel ratio and charging pressure. Since LPG is consisted of propane and butane, we investigated combustion characteristics using this two kinds of fuel. From the result of charging engine performance test, engine torque increase about 30% ∼ 40% with 0.3bar charging pressure. In low speed condition, as charging pressure increase, combustion stability improve ill lean bum condition, but, in high speed condition, combustion stability make worse in lean bum condition. We know that engine output decreased rapidly from the condition of air excess ratio 1.3. In addition, we measured emission characteristics under the lean bum and charging condition. From this experiment, we found that CO emission is out of the question in the range from stiochiometric to lean burn and charging condition, but charging pressure has influence on HC emission.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.31 no.3 s.258
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• pp.234-241
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• 2007

The regulations for hydrocarbon emission from vehicles have become much more stringent in recent years. These more stringent regulations request vehicle manufacturers to develop the advanced exhaust system for reducing exhaust emissions. The exhaust emissions has many sources in vehicle. In order to investigate the characteristics of hydrocarbon(HC) in the exhaust manifold, concentrations of individual HC species were measured in exhaust process. Using sampling valve, the light hydrocarbon emissions were captured in the exhaust manifold(catalyst before and after) and analyzed from LPLi engine exhaust manifold(catalyst before and after) using different fuel properties. Then exhaust samples were measured by gas chromatography(GC) and exhaust gas analyzer. Catalyst conversion efficiency for fuel properties of Butane 100% was better than Propane 100%. Start delay of LPLi engine was observed as increment of propane contents in LPG fuels.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2005.11b
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• pp.161-165
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• 2005

Until now LPG car has drived used to mixer and vaporizer. So LPG car always has problems back fire and when in the winter. LPG Car's Fuel consumption is rather than gasoline. But LPLi Fuel pump located in the fuel tank is directly injection in the engine. So Fuel consumption is better than LPG mixer system and result to reduced exhaust gas. In this paper to reduction of beating noise of LPLi(liquid phase LPG Injection) fuel pump. General speaking we know, beating noise is occur to near frequency each of pump. So we Modification of RPM through chang of amature turn number and area of dimension of the pump's body.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.7 no.3
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• pp.278-284
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• 2006

The popularity of the diesel engine revolves around its fuel efficiency, reliability, and durability compared to the gasoline engine. However, the main disadvantage of diesel engine is the emission of particulate matter (PM) which is known as carcinogenic substance. Therefore recent progress in engine management and after-treatment systems has led to great improvement to satisfy strict emission regulations. To comply with powerful environment regulations, this study is focused on the decrease of PM(soot) as to increase significantly exhaust temperature. Therefore, HC injection is used as the method to go to the PM regeneration temperature in front of filters composed of diesel oxidation catalyst(DOC) and diesel particulate filter(DPF). And especially, LPG is used because it has good chemical reactions with exhaust. In this study, we could manufacture the test bench thought LPG injection - with which soot can be decreased-, construct 3 kinds of database(DB) according to quantity of temperature to decide the LPG injection quantity and develop DPF ECU algorithm.