• Transactions of the Korean Society of Automotive Engineers
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• v.10 no.4
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• pp.7-14
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• 2002

In order to reduce exhaust omissions of spark ignition engine, it is important not only to improve catalyst conversion efficiency but also to directly reduce engine out exhaust emissions, during cold starting and warm up process. Therefore many researchers have been attracted to develop an early fuel evaporator(EFE) by Introducing a ceramic heater fur a solution of engine out exhaust emissions in SI engine. But, the performance of the EFE in MPI engine to reduce the exhaust emissions and to improve the cold startability has not been clarified yet. The purpose of this study is to evaluate the feasibility of a glow plug far EFE. Impinging spray using heated and unheated glow plug helps the vaporization of the fuel and heat up the three way catalyst sufficiently. The amount of CO, and UHC is reduced overall. The amount of NOx is higher at the initial stage, but become lower as time goes on than without glow plug.

• Transactions of the Korean Society of Automotive Engineers
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• v.9 no.2
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• pp.1-10
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• 2001

In order to reduce hydrocarbon emissions of spark ignition engine, it is important not only to improve catalyst conversion efficiency but also to reduce direct engine out hydrocarbon emissions, during cold starting and warm up process. Tjerefore many researchers have been attracted to develop an early fuel evaporator (EFE) by introducing a ceramic heater for a solution of engine out hydrocarbon emissions in SI engine. But, the performance of the EFE in MPI engine to reduce the exhaust emissions and to improve the cold startability has nat been clarified yet. The purpose of this study is to evaluate the feasibility of a glow plug for EFE.

• Journal of Mechanical Science and Technology
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• v.16 no.2
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• pp.270-278
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• 2002

In order to reduce the exhaust emissions of a spark ignition engine, it is important not only to improve the catalyst conversion efficiency, but also to directly reduce the engine-out exhaust emissions during a cold starting of the engine and warm up periods. The purpose of this study is to evaluate feasibility of a glow plug for an early fuel evaporator. In order to promote atomization, gasoline is injected on the glow plug with room temperature(20$\^{C}$) and high temperature(250$\^{C}$). To analyze the spray behavior characteristics, a PMAS is used to measure the SMD and the dropsize distribution of an impinging spray and a free spray. Results show that the evaporation rate of the impinging spray on the high temperature surface of the glow plug was higher than that of the free spray on the room temperature surface.

• Journal of Power System Engineering
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• v.1 no.1
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• pp.22-34
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• 1997

Circumstances require improving diesel engine, and many studies have been done in constant volume chamber(CVC). Because the combustion mechanism of a diesel engine has many difficulties with non-homogeneous nature, there has been a limitation to analyzing the combustion mechanism with CVC. Studies are often given in a real engine, but also it has difficulties in modifying configuration of combustion chamber etc. To get more easy way for mote engine-like test, a rapid compression mechanism has been introduced. This study addresses to designing a rapid compression expansion machine(RCEM) driven by compressed air, and to applying it on IDI diesel combustion chamber which has a glow plug. RCEM is introduced first and its characteristics are tested, then spray/combustion characteristics of diesel spray impinging on a glow plug in RCEM combustion chamber are investigated. The results show active combustion in the system employing spray impinging on a glow plug so as to improve combustion efficiency.

• Transactions of the Korean Society of Automotive Engineers
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• v.10 no.1
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• pp.84-92
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• 2002

On the cold start of LPG engine, as the engine temperature has not reached its equilibrium temperature, liquid LPG could not be changed perfectly gaseous LPG, although it was passed to the vaporizer. Liquid and gas mixed fuel could influence starting ability and exhaust emission characteristics of LPG engine. In this study, the vaporization characteristic of liquid LPG was investigated with a conventional vaporizer and the vaporizer with heat source(glow plug) installed at preheated chamber inlet, by using the visualization methods and engine test. According to visualization result, even if the engine coolant temperature was $14^{\circ}C$, liquid fuel was supplied to primary chamber over 25 seconds without vaporizing from preheated chamber in such a conventional vaporizer. However, the vaporizer with heat source do not correspond with that, scarcely had been trim on glow plug when LPG began to vaporize. The effectiveness of heat source could be verified by application to the conventional LPG engine.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.33 no.5
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• pp.99-105
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• 2005

Development of an engine with good fuel economy is very important for successful implementation of long endurance miniature UAVs (unmanned aerial vehicles). In the study, a 4-stroke glow-plug engine was modified to a gasoline-fueled spark-ignition engine. Engine tests measuring performance and friction losses were conducted to tune a simulation program for performance prediction. It has been found that excessive friction losses are caused by insufficient lubrication at high speeds. The simulation program predicts that engine power and fuel economy get worse with high altitude due to increasing portion of friction losses. The simulation results suggest quantitative guidelines for further development of a practical engine.

• Transactions of the Korean Society of Automotive Engineers
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• v.9 no.5
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• pp.54-61
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• 2001

It is reported that during the cold starting, especially in gasoline engine, the engine response and the effect of HC emission can be improved by prompting atomization and reducing the quantity of fuel adhered to the range of injector tip, inlet port, and inlet valve. The purposes of this study are to promote atomization of fuel before air-fuel mixture in the inlet port. In order to achieve its goal, the glow plug is to evaluate the feasibility of for the early fuel evaporator and the spray behavior characteristics of gasoline, injected on the surface of glow plug with room temperature(2$0^{\circ}C$) and high temperature(25$0^{\circ}C$) is to examine. Particle motion analysis system(PMAS) was used to measure the SMD and the dropsize distribution of impinging spray and free spray. The results of this experiment, evaporation rate of impinging spray was higher than that of free spray, and the higher evaporation rate win, the smaller peak dropsize was. Especially, during early spray SMD of impinging spray was still smaller than that of fee spray.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.29 no.7 s.238
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• pp.820-827
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• 2005

Development of an engine with good fuel economy is very important for successful implementation of long endurance miniature UAVs (unmanned aerial vehicles). In the study, a 4-stroke glow-plug engine was modified to a gasoline-fueled spark-ignition engine. Engine tests measuring performance and friction losses were conducted to tune a simulation program for performance prediction. It has been found that excessive friction losses are caused by insufficient lubrication at high speeds. The simulation program predicts that engine power and fuel economy get worse with high altitude due to increasing portion of friction losses. The simulation results suggest quantitative guidelines for further development of a practical engine.

• International Journal of Automotive Technology
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• v.8 no.4
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• pp.413-419
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• 2007

Experimental study of additives on the ignition performance of a compression ignition natural gas engine is introduced, followed by results of a simulation of its working mechanism. From the experimental results, it is understood that engine ignition performance can be improved when a certain amount of Di-tertiary-butyl peroxide additive is added. If the mass fraction of Di-tertiary-butyl peroxide additive reaches as high as 14.2%, engine ignition can be realized at ambient temperatures with a glow plug temperature of about $750^{\circ}C$. From the simulation results, we verify that the Di-tertiary-butyl peroxide additive, by cracking its radicals at lower temperature, can accelerate reaction rate. Therefore, the additive is able to improve the ignition performance of natural gas significantly.

• Journal of the Korea Institute of Military Science and Technology
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• v.8 no.1 s.20
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• pp.49-55
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• 2005

Due to small and light mission payloads, subsystems and propulsion system, small sized UAVs come to be available for reconnaissance that have been performed by aircraft and huge UAVs. The objective of this study is to develop an efficient propulsion system for small reconnaissance UAVs. A glow engine was modified for an efficient and robust 4-stroke gasoline engine with carburetor, new electronic control unit and lubrication system. Engine modification technique and small engine performance test stand are capable of economical method for military UAVs.