LP가스 액상공급 시스템에 관한 연구

최수진(Sujin Choi),강건용(Kemyong Kang) 한국자동차공학회 2003 한국자동차공학회 춘 추계 학술대회 논문집 Vol.- No.-

An experimental study was carried out to obtain fundamental data about liquid state gas fuel supply pump. Two types of pumps were used. One was a regenerative type which was generally used for gasoline engine fuel system. The other was a roller-vane type which was also used for automotive engine fuel system. The experiments were performed to obtain flow rate as a function of pressure differences and temperatures.<br/> The regenerative pump had low flow rate at some experimental conditions. Therefore, it is impossible to use this pump system for liquid state gas fuel supply system. On the other hand, the roller-vane type pump can be applied to the system only if its check valve is modified. Cavitation might occur in this system which can result in system noise, flow rate variation, and pump durability problem. To solve these problems the system is needed to increase NPSH_re(requried net positive suction head).

대형엔진용 액상분사식 LPG 연로공급 방식에 대한 기초연구 (1)

김창업(Changup Kim),오승묵(Seungmook Oh),강건용(Kemyong Kang) 한국자동차공학회 2001 한국 자동차공학회논문집 Vol.9 No.4

LPG has been well known as a clean alternative fuel for vehicles. As a fundamental study on liquid phase LPG injection (hereafter LPLI) system application to heavy-duty engine, engine output and combustion performance were investigated with various operating conditions using a single cylinder engine equipped with the LPLI system. Experimental results revealed that no problems were occurred in application of the LPG fuel to heavy-duty engine, and that volumetric efficiency and engine output, by 10% approximately, were increased with the LPLI system. It was resulted from the decrease of the intake manifold temperature through liquid phase LPG fuel injection. These results provided an advantage in the decrease of the exhaust gas temperature, in the control of knocking phenomena, spark timing and compression ratio. The LPLI engine could normally operated under ??=1.5 or EGR 30% condition. The optimized swirl ratio for the heavy duty LPG engine was found around R_s = 2.0.

액상분사식 대형 LPG 엔진의 연소실 형상 및 연료조성 최적화 연구

김창업(Changup Kim),오승묵(Seungmook Oh),강건용(Kemyong Kang) 한국자동차공학회 2001 한국자동차공학회 춘 추계 학술대회 논문집 Vol.2001 No.5_1

Recently, several LPG engines for heavy-duty vehicles have been developed, which can replace some diesel engines that are one of a main source for air pollution in urban area. As a preliminary study on the liquid phase LPG injection (hereafter LPLI) system applicable to a heavy duty LPG engine, the engine output and combustion performance were investigated with various combustion chambers and fuel compositions using a single cylinder engine equipped. Experimental results revealed that ellipse, double ellipse and Nebula type combustion chamber made a more advantage in breaking swirl flow into small turbulence scale than bathtub type. Especially, performance of nebula type showed most highest efficiency and engine output under lean mixture conditions. An investigation for various LPG fuel compositions was also carried out, and revealed that the case with 40% propane and 60% butane shows the lowest efficiency at stoichiometry, however, as the mixture became leaner its efficiency increased and became even higher for 100% propane case.<br/> <br/> <br/>

Simulation on the control of HCCI combustion using a quick-response electromagnetic valve mechanism

Young Choi(최영),Jinho Kim(김진호),Kemyong Kang(강건용) 한국자동차공학회 2006 한국자동차공학회 춘 추계 학술대회 논문집 Vol.- No.-

For Homogeneous Charge Compression Ignition (HCCI) engine, which is a desirable compromise between spark ignition (SI) engine and compression ignition (CI) engine, controlling the initiation of combustion remains as a challenge for practical applications. Unlike Sl engines in which a spark plug is used and CI engines in which a fuel injector is used, HCCI engine has no direct method to control the initiation of combustion. Therefore, indirect ways have been suggested. One of the most promising indirect methods to control the combustion timing is to adopt the technology of variable valve timing (VVT). The VVT can not only solve the control problem in HCCI engine, but also achieve a significant improvement in fuel economy and lower emissions. In order to replace the conventional double solenoid type actuator which has low efficiency and difficulty in initial movement, a newly developed liner actuator with permanent magnets was introduced. The designed electromagnetic VVT mechanism shows a fast transition time between valve events and it is found to be suitable for the practical usage in HCCI combustion control. The validity of using this quick-response electromagnetic valve for the HCCI control is examined through the simulation with a well mixed reactor (WMR). The parametric study with a WMR associated with the proposed electromagnetic valve VVT system, shows potential for practical application to the control of HCCI combustion.

대형 액상분사식 LPG엔진 인젝터의 아이싱 특성연구

김창업(Changup Kim),오승묵(Seungmook Oh),강건용(Kemyong Kang) 한국자동차공학회 2003 한국자동차공학회 춘 추계 학술대회 논문집 Vol.- No.-

The liquid phase LPG injection (LPLI) system (the third generation technology) has been considered as one of the next generation fuel supply systems for LPG vehicles, since it has a very strong potential to accomplish the higher power, higher efficiency, and lower emission characteristics than the mixer type(the second generation technology) fuel supply system. However, when a liquid LPG fuel is injected into the inlet duct of an engine, a large quantity of heat is extracted due to evaporation of fuel. This leads to freezing of the moisture in the air around the outlet of a nozzle, which is called icing phenomenon It may cause damage to the outlet nozzle of an injector or inlet valve seat. In this work, the experimental investigation of the icing phenomenon was carried out. The results showed that the icing phenomenon and process were mainly affected by humidity of inlet air instead of air temperature in the inlet duct. Also, it was observed that the total ice formed around the nozzle weighs at about l50mg-260mg after injection for ten minutes. And some fuel species were found in the ice attached at the front side of a nozzle, while frozen ice attached at the back of a nozzle was mostly consisted of moisture of inlet air. Therefore, some frozen ice deposit, detached from front nozzle of an injector, may cause a problem of unfavorable air fuel ratio control in the small LPLI engine.

대형 LPG 엔진의 이중점화 적용연구

김창업(Changup Kim),오승묵(Seungmook Oh),강건용(Kemyong Kang) 한국자동차공학회 2002 한국자동차공학회 춘 추계 학술대회 논문집 Vol.2002 No.5_3

An LPG engine for heavy duty vehicles has been developed using liquid phase LPG injection (hereafter LPLI) system, which has regarded as one of the next generation LPG fuel supply systems. In this work to investigate the lean burn characteristics of heavy duty LPLI engine, various injection timing (SOl, start of injection) and double ignition method were tested. The results showed that lean misfire limit could be extended, by 0.2λ value, using the optimal SOl timing and engine performances were increased as well. Double ignition method was carried out by installing the second spark plug and modified ignition circuit to ignite the two spark plug simultaneously. Double ignition resulted in the stable combustion under ultra lean bum condition, below λ=1.7, and extension of lean misfire limit, by 0.2 λ value, compare to ordinary case. Therefore, LPLI engine with optimal SOl and double ignition method could be normally operated at around λ = 1.9 and showed higher engine performance.

대형엔진용 액상분사식 LPG 연료공급방식에 대한 기초연구(2)

김창업(Changup Kim),오승묵(Seungmook Oh),강건용(Kemyong Kang) 한국자동차공학회 2001 한국 자동차공학회논문집 Vol.9 No.6

Recently, several LPG engines for heavy-duty vehicles have been developed, which can replace some diesel engines that are one ofa main source for air pollution in urban area, As a preliminary study on the liquid phase LPG injection (hereafter LPLI) system applicable to a heavy duty LPG engine, the engine output and combustion performance were investigated with various combustion chambers and fuel compositions using a single cylinder engine equipped. Experimental results revealed that ellipse, double ellipse and nebula type combustion chamber made a more advantage in breaking swirl flow into small turbulence scale than bathtub type. Especially, performance of nebula type showed most highest efficiency and engine output under lean mixture conditions. An investigation for various LPG fuel compositions was also carried out, and revealed that the case with 40% propane and 60% butane shows the lowest efficiency at stoichiometry, however, as the mixture became leaner its efficiency increased and became even higher for 100% propane case.<br/>

[가솔린엔진부문] 대형 LPG 엔진에서의 화염 가시화에 의한 연소특성 연구 (연소실 형상과 분사시기 및 공연비의 영향)

김승규(Seungyu Kim),배충식(Choongsik Bae),오승묵(Seungmook Oh),김창업(Changup Kim),강건용(Kemyong Kang) 한국자동차공학회 2001 한국자동차공학회 춘 추계 학술대회 논문집 Vol.2001 No.11_1

Combustion and flame propagation characteristics of LPG engine were investigated in a single cylinder optical engine. A lean burn operation is important not only to enhance fuel economy but also to reduce the thermal stress of a heavy duty LPG engine. There have been lots of efforts to enhance lean operation. As a result, it is well known that the in-cylinder bulk flow, swirl and tumble, and the injection timing are important in enhancing lean operation.<br/> In this study, the effects of piston geometry and injection timing on flame characteristics were investigated. A series of bottom, view flame images were taken using a high-speed camera in one cycle. Concepts of flame area velocity and flame propagation patterns were introduced to analyze the flame characteristics.<br/> The results show the correlation between the f1ame propagation characteristics, which is related to LML and engine design parameters such as piston geometry and injection timing. The piston geometry has significant effect on bulk flow i.e. swirl and squish flow, which subsequently affect f1ame characteristics<br/>

EGR 성층화가 액상 분사 LPG 엔진의 성능에 미치는 영향

우영민(Youngmin Woo),배충식(Choongsik Bae),오승묵(Seungmook Oh),강건용(Kemyong Kang) 한국자동차공학회 2003 한국자동차공학회 춘 추계 학술대회 논문집 Vol.- No.-

EGR (exhaust gas recirculation) utilizes the diluents into the engine cylinder to control combustion leading to enhanced fuel economy and reduced emissions. However, with high diluent rate, the occurrence of excessive cyclic variation brings about an undesirable combustion instability resulting in the deterioration of engine performance. Proper stratification of diluent could improve the combustion stability under high diluent environment.<br/> EGR stratification within the cylinder was made by adopting a fast-response solenoid valve in the midst of EGR line and controlling its timing and duty. With supplying EGR in both homogeneous mode and stratified mode, thermodynamic heat release and flame propagation characteristics were investigated in an optically accessible single cylinder engine. Shorter burning duration and faster flame propagation were found in the case of stratified EGR than homogeneous EGR. PLIF images gave the EGR distribution within cylinder to show that EGR occupied the lower part of cylinder through the stratification process and this could help reducing the burning duration.<br/>

LPG 액상분사 엔진에서 아세톤 PLIF를 이용한 연료분포 측정기법 연구

박승재(Seungjae Park),허환일(Hwanil Huh),오승묵(Seungmook Oh),강건용(Kemyong Kang),배충식(Choongsik Bae) 한국자동차공학회 2004 한국 자동차공학회논문집 Vol.12 No.1

Planar laser-induced fluorescence(PLIF) has been widely used to obtain two dimensional fuel distribution. Acetone PLIF is chosen because fluorescence signal from acetone as a fluorescent tracer is less sensitive to oxygen quenching than other dopants. Acetone PLIF is applied to measure quantitative air excess ratio distribution in an engine fueled with LPG. Acetone is excited by KrF excimer laser (248nm) and its fluorescence image is acquired by ICCD camera with a cut-ofT filter to suppress Mie scattering from the laser light. For the purpose of quantifying PLIF signal, an image processing method including the correction of laser sheet beam profile is suggested. Raw images are divided by each intensity of laser energy and profile of laser sheet beam. Inhomogeneous fluorescence images scaled with the reference data, which is taken by a calibration process, are converted to air excess ratio distribution. This investigation shows instantaneous quantitative measurement of planar air excess ratio distribution for gaseous fuel.<br/>