• 한국자동차공학회논문집
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• 제13권3호
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• pp.87-95
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• 2005

Most of the motorcycle engines have used carburetors in the fuel system, because of its simple structure and reliability but the fuel economy and the emissions of those engines are bad when we compared with automobile engines .To meet with the tighten emission regulations and the higher requirements for fuel economy, the application of the carburetor on the motorcycle engines would be limited. Therefore, it is important to develope a ECU control system for motorcycle engines. Since the fuel injection system is expensive, it is necessary to decrease the cost of ECU system for motorcycle engines, but the accuracy of the ECU control system should be increased as high as possible. In this paper, we studied about the AFS characteristics of motorcycle engine controled by indirect method.

• 산업경영시스템학회지
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• 제36권4호
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• pp.71-76
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• 2013

For a die casting mold, generally, the casting layout design should be considered based on the relation among injection system, casting condition, gate system, and cooling system. Also, the extent or the location of product defects was differentiated according to the various relations of the above conditions. In this research, in order to optimize the casting layout design of an automotive Oil Pan_DX2E, Computer Aided Engineering (CAE) simulation was performed with two layout designs by using the simulation software (AnyCasting). The simulation results were analyzed and compared carefully in order to apply them into the production die-casting mold. During the filling process with two models, internal porosities caused by air entrapments were predicted and also compared with the modification of the gate system and overflow. With the solidification analysis, internal porosities occurring during the solidification process were predicted and also compared with the modified gate system.

• 한국연소학회:학술대회논문집
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• 한국연소학회 2014년도 제49회 KOSCO SYMPOSIUM 초록집
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• pp.273-275
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• 2014

An ammonia fuel system is developed and applied to both a spark ignition engine and a compression ignition engine to use ammonia as primary fuel in this study. Ammonia is injected separately into the intake manifold in liquid phase while gasoline or diesel is also injected as secondary fuel. As ammonia burns 1/6 time slower than gasoline or diesel, the spark or diesel injection timing is needed to be advanced to have better combustion phasing. The test engine showed quite high variation in the power output with large amount of ammonia. The final goal of the study is to implement a methodology to ignite ammonia-air mixture and have complete combustion without any use of the conventional fuels.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2001년도 춘계학술대회논문집E
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• pp.107-112
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• 2001

The effect of ambient gas (steam) condensation on swirl spray characteristics were studied experimentally for low subcooling condition of the liquid. The configuration of the liquid(water) sheet and the breakup modes were examined. Also variation of the discharge coefficient, breakup length, local and the cross-sectional area-averaged SMD of droplets with the liquid flow(injection) rate were obtained. The perforation breakup mode appears dominant with condensation while the aerodynamic wave breakup mode is dominant without condensation(in the air environment). The discharge coefficient, breakup length and the mean drop sizes decrease in a same manner with increasing of the liquid flow rate for both cases(with and without condensation). The condensation effects are insignificant with the discharge coefficient. However, the local and cross-sectional area-averaged SMD are larger and the breakup length becomes shorter in the steam environment. The spray angle predicted from the volumetric flux distribution along the radial direction of the sprays in the steam environment becomes larger with condensation.

• 대한기계학회논문집
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• 제17권5호
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• pp.1276-1293
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• 1993

본 연구는 위에서 언급된 모델보다 훨씬 폭이 큰 23.5mm 루버 핀형 방열기용 열교환기를 모델로 삼고, 레이놀즈수가 500 이하인 저 레이놀즈수(100, 300, 500), 루버 각(22˚,24˚,28˚) 및 핀 피치 와 루버 피치의 비 Fp /Lp(1.23, 1.5) 등의 변화 에 따른 핀 내부의 유동, 전열 특성 및 압력분포등의 영향을 유한차분법으로 수치해석 하였다. 또한 동일한 루버 핀에대해 13:1 모델을 제작하여 염료주입법에의한 유동의 가시화 실험을 하였으며, 그 결과를 수치해석 결과와 비교 검토하였다.

• 한국분무공학회지
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• 제1권1호
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• pp.55-62
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• 1996

In a fuel injection engine, atomization of liquid fuel and mixture formation process has influenced(or affected) directly on the engine performance and pollutant emission. In this study, the characteristics of fuel spray and the behaviors of secondary atomization developed at the downstream of the valves were investigated using an image processing method. Solid and perforated valves are chosen in order to evaluate the valve performance in terns of air flow rate, valve opening angle and valve shape. Experimental results clearly indicate that the spray atomization quality can be improved by increasing the perforated rat io and the blockage rat io in the perforated valve, the characteristics of spray atomization is improved by using the perforated valve with high perforated rat io and blockage ratio.

• 한국분무공학회지
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• 제1권2호
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• pp.50-56
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• 1996

In an fuel injection type gasoline engine, atomization of fuel droplet and mixture formation process are very important to understand engine combustion efficiency, and also has influence directly on the decision of engine performance and pollutant emission. In this study, perforated throttle valve instead of solid type throttle valve was developed and equipped to an SPI engine to promote secondary atomization and good droplet-air mixture formation. From the engine performance lest. it was verified that the case of perforated valve kas more advantages in each experimental parameters such as in cylinder gas pressure, mass burnt ratio, fuel consumption rate, and pollutant emission characteristics than that of solid one equipped. No matter what the same perforated valve, there are some distinct results in engine performance characteristics according to the perforate ratio.

• 한국분무공학회지
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• 제1권2호
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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.

• 한국대기환경학회:학술대회논문집
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• 한국대기환경학회 2003년도 춘계학술대회 논문집
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• pp.102-103
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• 2003

최근 고도 경제성장으로 인한 공업화와 그에 따른 업종이 다양해짐에 따라 여기에 수반되어 발생되는 대기오염물질이 증가할 뿐만 아니라 종류도 여러가지로 다양해지고 있다. 대부분 산업공정에서 배출되는 미세먼지 입자는 기존의 집진장치로 거의 포집제거가 불가능하여 대부분이 대기중으로 방출되고 있는 실정이다. 분진 중에서도 입경 l$\mu\textrm{m}$이하의 분진들은 침강 속도가 작아 거의 gas와 동일한 거동을 하기 때문에 기관 또는 폐포에 침착하여 호흡기에 영향을 미치므로 그 발생량과 화학적 성상이 문제화되고 있는 추세이다. (중략)

• 전기의세계
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• 제22권5호
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• pp.5-11
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• 1973

A new method of forming silicon p$^{+}$-n-n$^{+}$ junctions has been attempted by using the VDH-Implanter (Vacuum Discharge and Heating). Each of p$^{+}$-n and n-n$^{+}$ junctions was formed on both sides of an n-type silicon substrate by means of predeposition of each dopant and their bombarding due to rarefied air ions together with the preheating of the substrate in the implanter. The recifying principle of the p$^{+}$-n-n$^{+}$ junctions is thought to be based on the theory of double injection. The I-V characteristic of the diode has shown that it has a fairly high forward current density with the desirable rise due to vary low voltage though the reverse voltage is a little low on account of the low resistivity of the silicon substrate.n substrate.