• Journal of ILASS-Korea
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• v.1 no.2
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• pp.33-41
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• 1996

Mixture formation is one of the important factors to improve combustion performance of MPI gasoline engines. This is affected by spray and atomization characteristics of injector. Especially, in the case of EGI system, air-fuel mixing period is too short and formed a lot of fuel-film in the intake manifold and cylinder wall. This fuel-film is not burnt in cylinder, it is exhausted in the form of HC emission. In this paper, spray characteristics such as size distributions, SMD, and spray angle are measured by PMAS, and the fuel-film measuring device is developed specially. Using this device, the amount and distribution of fuel-film which flows into through valve can be measured Quantitatively. As the result of these experiments, the information of optimal spray characteristics and injection condition that minimize the fuel-film can be built up.

• Proceedings of the KAIS Fall Conference
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• 2009.12a
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• pp.526-530
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• 2009

본 연구은 자동차용 가솔린엔진에 장착되는 인젝터의 연료공급 특성에 대한 것으로, 가솔린 엔진의 전자제어식 포트 연료분사는 분무장치와 흡기포트의 최적화 및 분무특성이 우수해야 엔진의 성능 향상 및 배기가스 저감의 목적을 이룰 수 있다. 4홀과 12홀 인젝터의 장착각 변화와 포트 마스킹의 형상변화에 따른 벽유량을 측정?분석하였고 분무가시화 실험을 통하여 분무성장과정과 분사각, 연료미립화 및 분무도달거리를 분석하였다. 벽류측정 실험을 통하여 벽류는 미립화정도와 흡기유동과 유속에 가장 큰 영향을 받는 것으로 판단되며, 12홀 인젝터 대비 4홀 인젝터는 분무압력에 따라 분무특성의 변화량이 크게 나타났다.

• Proceedings of the KAIS Fall Conference
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• 2009.05a
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• pp.539-542
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• 2009

본 연구은 자동차용 가솔린엔진에 장착되는 인젝터의 연료공급 특성에 대한 것으로, 4홀과 12홀 인젝터의 분무질량분포, 벽류 및 가시화 실험을 수행하였다. 분무질량분포 실험을 통하여 인젝터 별 분무특성을 파악하고, 벽류측정실험을 통하여 흡기포트내의 연료 Wetting 특성을 확인하였다. 가시화실험을 통하여 분사각과 분무특성을 비교 분석하였다. 4홀과 12홀 인젝터의 분무특성비교를 통한 각 인젝터의 연료공급 특성분석은 가솔린엔진 설계시 기초자료로 활용될 수 있을 것이다.

• Journal of ILASS-Korea
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• v.2 no.4
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• pp.15-21
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• 1997

In a gasoline engine with port injection system, the fuel behavior in the intake port has significant influence on the HC emission and the precise A/F control. That is to say, it is inevitable that the injection direction and behavior of fuel injected in the intake port have an effect on the generation of unburned HC within a cylinder. In this paper, we visualized fuel behavior in the intake port using micro CCD camera synchronized with the stroboscope and investigated the fuel-film characteristics formed at the wall of intake port by processing image captured with VCR in the transparent intake port made of acryl. Using these measuring methods, it was found that fuel behavior and the formation of fuel-film in the intake port could be evaluated qualitatively. And results obtained by these methods show that 2-spray injector minimizes the fuel-film formed in the intake port of a DOHC gasoline engine.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.22 no.11
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• pp.1530-1537
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• 1998

Mixture formation is one of the significant factors to improve combustion performance of an spark ignition engine. This is affected by spray and atomization characteristics of injector. In the case of EGI system, air-fuel mixing period is so short that a lot of fuel-film and liquid-fuel flow into cylinder. Since this fuel-film is not burnt perfectly in cylinder, it is exhausted in the form of HC emission. In this paper, three measurement techniques were utilized to measure spray characteristics and the amount of fuel-film in the cylinder. At first, PMAS was used to measure the spray characteristics such as size distributions, SMD, and spray angle. Secondly the amount and distribution of fuel-film which flow into through intake valve could be measured quantitatively using the fuel-film measuring device. And lastly, by optical fiber type spark plug used to detect the diffusion flame, the amount of unburned HC was measured. As the result of these experiments, the information of optimal spray characteristics and injection condition to minimize fuel-film could be built up.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.11 no.3
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• pp.815-820
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• 2010

Fuel spray characteristics of the gasoline engine injector has been studied experimentally. Wall wetting fuel stream of the 4-hole and 12-hole injectors has been tested and measured with various installation angle and port masking shapes. Spray visualization has been performed to analyze spray formation, spray angle, and penetration length. Test result shows that wall wetting is greatly influenced by the induction air flow and injector installation angle. Wall wetting amount decreased as injector installation angle decreased. Masking decreased wall wetting amount by increasing local intake-air flow velocity due to the decreased section area. Spray visualization showed that the 12-hole injector has robust performance characteristics compared with the 4-hole injector.

• Transactions of the Korean Society of Automotive Engineers
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• v.11 no.3
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• pp.20-27
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• 2003

In this paper, the fuel transport characteristics during transient condition was studied by using a Fast Response Flame Ionization Detector(FRFID). The quantitative measurement method for the inducted fuel mass into cylinder is studied. The inducted fuel mass into the cylinder was estimated by using calculated air-fuel ratio by hydrocarbon concentration of cylinder and air flow model. In order to estimate the transportation of injected fuel from the intake port into cylinder, the wall wetting fuel model was used. The two coefficient $\alpha$,$\beta$) of the wall-wetting fuel model was determined from the measured fuel mass that was inducted into the cylinder at the first cycle after injection cut-off To reduce an air/fuel ratio fluctuation during rapid throttle opening, the appropriate fuel injection rate was obtain from the wall wetting model with empirical coefficients. Result of air/fuel ratio control, air/fuel excursion was reduced.

• Journal of ILASS-Korea
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• v.15 no.2
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• pp.61-66
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• 2010

Fuel spray characteristics of the gasoline engine injector has been studied experimentally. To provide fundamental performance data of 4-hole and 12-hole injectors, spray fuel-mass distribution, wall wetting fuel amount and visualization of injectors have been tested and measured with various fuel supply pressure conditions. Spray visualization has been performed to analyze spray formation, spray angle, stream width and penetration length. Test result shows that wall wetting is greatly influenced by the induction air amount and spray atomization. Spray visualization shows that the 12-hole injector has robust performance characteristics with various fuel supply pressure conditions compared with the 4-hole injector. 4-hole injector generates relatively less wall-wetting fuel amount than 12-hole injector does.

• Transactions of the Korean Society of Automotive Engineers
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• v.10 no.4
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• pp.15-22
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• 2002

As the emission regulations on the automobiles have been increasingly stringent, precise control of air/fuel ration is one of the most important issues on the gasoline engines. Although many researches have been carried out to identify the fuel transport phenomena in the port fuel injection gasolines, mixture preparation in the cylinder has not been fully understood due to the complexity of fuel film behavior, In this paper, the mixture preparation during cold engine start is studied by using a Fast Response Flame ionization Detector.(FRFID) In order to estimate the transportation of injected fuel from the intake port into cylinder, the wall wetting fuel model was used. The two coefficient($\alpha$,$\beta$) of the wall-wetting fuel model was determined from the measured fuel mass that was inducted into the cylinder at the first cycle after injection cut-in. $\alpha$( ratio of directly inducted fuel mass into cylinder from injected fuel mass) and $\beta$ (ratio of indirectly inducted fuel mass into cylinder from wall wetted fuel film on the wall) was increased with increasing cooling water temperature. To reduce a air/fuel ratio fluctuation during cold engine start, the appropriate fuel injection rate was obtained from the wall wetting fuel model. Result of air/fuel ratio control, air/fuel excursion was reduced.

• Transactions of the Korean Society of Automotive Engineers
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• v.7 no.8
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• pp.116-122
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• 1999

According to the stringent exhaust emission regulation, precise control of air fuel ratio is one of the most important issues on gasoline engine. Although many researches have been carried out to identify the fuel transport phenomena in a port fueled gasoline engine, complexity of fuel film behavior in the intake port makes it difficult. The fuel film behavior was investigated recently by using visualization method and these gave us qualitative understanding. The purpose of this study is to estimate of wall wetting fuel in the intake port and the inducted fuel mass was predicted by using wall wetting fuel model . The model coefficient($\alpha$,$\beta$) and fuel film mass on the port wall were determined from measured in-cylinder HC concentration using FRFID after injection off. The fuel film mass was increased, but $\alpha$(ratio of directly inducted fuel mass into cylinder from injected fuel mass) was decreased with increasing load at the same engine speed. $\beta$is nearly constant value(0.8~0.9). when injected fuel mass is varied at 1500rpm , the calculated air fuel ratio using well wetting fuel model was nearly the same as measured by UEGO.