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고속 유동 계측을 위한 PIV 시스템 개발에 관한 연구
이창식(c.s. Lee),이기형(K.H. Lee),전문수(M.S. Chon),김영호(Y.H. Kim) 한국자동차공학회 1996 한국자동차공학회 춘 추계 학술대회 논문집 Vol.1996 No.11_2
Abstract: An analysis of the spatial structure in flow field is very important thing in an engine inlet system. In this study, the PIV(Particle Image Velocimetry) system is developed to analyze high velocity and the bulk flow motion in a gas flow field. The single-frame double pulsed technique is used with 2-D Fourier transform and 2-D auto-correlation algorithm. The discrete Fourier transform of magnified particle pairs is taken numerically to make the fringe image. And then taking inverse Fourier transform of fringe image results in the correlation pattern. Flow visualization technique and single-trame PTV(Particle Tracking Velocimetry) are employed to clear directional ambiguity as well. And the PIV system is applied to measure the velocity field of gasoline fuel spray and cylinder flow in steady flow test bench. In fuel spray experiments, the axial velocity is getting larger downward, and radial velocity is getting smaller outward. And the spatial resolution in PIV is much higher than that of PTV in obtaining velocities.
PTV 시스템을 이용한 가솔린 기관의 실린더내 정상 유동 해석
이창식(C.S. Lee),이기형(K.H. Lee),전문수(M.S. Chon),임경수(K.S. Im) 한국자동차공학회 1996 한국자동차공학회 춘 추계 학술대회 논문집 Vol.1996 No.6_2
Analysis and control of intake charge motion such as swirl and tumble are very important factors in improving the gasoline engine performance. In this work, the flow visualization technique and single-frame PTV(particle tracking velocimetry) are use to the steady flow test bench with 4-valve and pent-roof combustion chamber. Tumble pattern is visualized and quantified in accordance with valve lift and blockage ratio of TIV(tumble intensifying valve) and also the TIV port compare with the conventional port. The view of the instantaneous 2-D velocity field gives a realistic understanding of in-cylinder flow and thus PTV has proven to be an indispensable development tools. This flow has two tumble structures, the larger one is observed under exhaust valve side and the smaller is right below the intake valve side. The more large vorticity is observed in TIV port, thus it is concluded that TIV has effects in-cylinder flow on intensified kinetic energy.<br/>
흡기 조건 변화에 따른 4밸브 가솔린 기관의 실린더내 유동 특성에 관한 연구
이창식(C.S.Lee),이기형(K.H.Lee),전문수(M.S.Chon),김영호(Y.H.Kim),정성환(S.H.Chung) 한국자동차공학회 1998 한국자동차공학회 춘 추계 학술대회 논문집 Vol.1998 No.11_1
In-cylinder bulk flow of 4 valve single cylinder gasoline engine under variable intake conditions were investigated in this experimental study to verify the correlation in-cylinder flow characteristics and intake conditions such as dual intake valve working, single intake valve working and dual intake valve with tumble intensifying valve(TIV) and swirl intensifying valve(SIV). Single frame particle tracking velocimetry was employed to measure the in-cylinder flow velocities quantitatively. The results were that under baseline engine and TIV adapted condition the flow had smaller radius of principal tumble and still had enough momentum to keep their direction over compression force made by decreased volume. However the mean flow velocities and tumble ratios were decreasing after BDC. TIV had effects on tumble ratio so as to give 1.35 times as strong as tumble ratio.<br/>
포트 분사식 가솔린 인젝터의 분무 구조에 관한 실험적 연구
이창식(C.S.Lee),전문수(M.S.Chon),손강호(K.H.Sohn),박종순(J.S.Park) 한국자동차공학회 1998 한국자동차공학회 춘 추계 학술대회 논문집 Vol.1998 No.5_1
This experimental study describes the spray structure of gasoline port fuel injectors by using PDPA(phase Doppler particle analyzer) and PMAS(particle motion analysis system). The macro characteristics of fuel spray such as the spray penetration, spray angle and breakup process were captured by PMAS and the micro characteristics of fuel spray such as droplet size and velocity were obtained by PDPA. New Pintle type and two-hole type injectors were used as gasoline port fuel injectors under various injection pressures. The correlation between SMD and injection pressure and between axial velocity and injection pressure will be discussed. And the comparison of breakup processes for the two types of injectors was also conducted. It is shown that new Pintle type injector has smaller droplet size than that of two-hole type injector.<br/>
직접분사식 디젤엔지에서 엔진성능과 배출가스에 대한 유화연료의 효과
이창식(C.S.Lee),로스리(ROsli Abu Bakar),김정훈(J.H.Kim) 한국자동차공학회 1997 한국자동차공학회 춘 추계 학술대회 논문집 Vol.1997 No.6_1
The purpose of this investigation is to carry out the effect of emulsified fuel on the combustion performance and exhaust emissions in direct injection type diesel engine. To control the emission in direct injection type diesel engine, the effect of emulsified fuel on the combustion and reduction of exhaust emissions was investigated by experiment.<br/> In this study, the experiment was conduct with a single cylinder diesel engine with the various water contents in the fuel. The results showed that the emulsified fuel results in the reduction of exhaust emissions and improve the engine performance in the engine. It found that emulsified fuel increased the cylinder pressure and the rate of heat release of engine.<br/>
MPI 엔진용 공기 보조 인젝터의 분무 미립화 및 및 연소 특성에 관한 연구
이창식(C. S. Lee),이기형(K. H. Lee),서영호(Y. H. Seo) 한국자동차공학회 1996 한국자동차공학회 춘 추계 학술대회 논문집 Vol.1996 No.11_2
The spray characteristics of air-assisted fuel injection and its effects on the lean combustion was investigated in this study. The atomization characteristics of a Bosch fuel injector inserted into the air-assist adapter is measured with PMAS. Droplet size decreased with air supplied and fine spray with below 6O㎛ of SMD is acquired at the assistant air pressure over O.5bar. The lean combustion performance of a 1.8L DOHC engine equipped with air-assist adapters is tested on the dynamometer. When the assistant air pressure is increased. lean limit was extended, and fuel consumption and emissions were decreased.
이창식(C.S.Lee),서영돈(Y.D.Suh) 한국자동차공학회 1993 한국자동차공학회 춘 추계 학술대회 논문집 Vol.- No.-
The characteristics of combustion variation and combustion performance in a multi-point injection<br/> gasoline engine are investigated using experiments and theoretical simulation.<br/> In this study. the variations of combustion characteristics was analyzed by using the coefficient of<br/> variation and combustion characteristics of engine.<br/> The results of this work show that the variation coefficient of mean effective pressure and maximum pressure in cylinder are decrease with the increase of engine speed. The cycle variation of pressure characteristics and combustion rate of engine are also discussed.<br/>
이창식(C.S.Lee),김정헌(J.H.Kim) 한국자동차공학회 1992 한국자동차공학회 춘 추계 학술대회 논문집 Vol.- No.-
This paper deals with the results of injection characteristics and the influence parameters upon the fuel injection performance of the inline injection system in a diesel engine. In this study, the characteristics of the injection rate, the injection pressure and the injection duration have been investigated by changing the injection parameters. The predicted results and injection performance are compared to the measured data from the injection test system.<br/> <br/>
[가솔린엔진] 흡기 유동 조건의 변화가 실린더 내 가스 유동 패턴에 미치는 영향
이창식(C.S. Lee),전문수(M.S. Chon),김우경(W.K. Kim),최수천(S.C. Choi) 한국자동차공학회 1999 한국자동차공학회 춘 추계 학술대회 논문집 Vol.- No.-
This paper presents the characteristics of the gas flow in the engine cylinder under various intake flow conditions. The single-ㄹrame particle tracking velocimetry(PTV) was applied to analyze the gas flow pattern and flow field in the cylinder. Effects of tumble intensifying valve(TIV), swirl intensifying valve(SIV), and one-valve deactivated condition on in-cylinder flow patterns were compared with the baseline engine under 600rpm motoring condition. In addition, tumble ratio was estimated with results of in-cylinder flow fields. Base on experimental results, the tumble ratio of in-cylinder flow field has the maximum value at the bottom dead center for the different four inlet conditions. In TIV condition, the tumble ratio is 1.35 times larger than that of baseline engine and I intake valve deactivated condition is effective to improve in-cylinder swirl motion