• Journal of the Korean Chemical Society
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• v.35 no.6
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• pp.699-706
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• 1991

The moderate power (500 W) Microwave Induced Plasma was generated with helium gas and was used for the direct analysis of aqueous samples. Usually, the helium plasma obtained with a modified Beenakker type cavity forms a cylindrical one. Though, by the careful controls of gas flows, a "toroidal" shape plasma could be made but its analytical performances were found to be worse. Using the glass frit nebuliser, the detection limits for metal ions obtained were around 10~100 ppb and that for chloride was about 50ppm.

• Transactions of the Korean Society of Automotive Engineers
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• v.10 no.3
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• pp.18-27
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• 2002

Flame behavior in inner and outer the cavity and flame temperature have an important influence on the formation and oxidation of NOx and soot. Therefore, in this study, the combustion chamber of toroidal and reentrant that have different flow characteristics of inside and outside the cavity and load, and so forth are determined as parameters of experimental conditions. An attempt has been made to obtain the effect of flame temperature and KL value in idler and outer cavity on the formation and oxidation of soot using the two-color method.

• Journal of ILASS-Korea
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• v.7 no.1
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• pp.7-13
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• 2002

This paper is study on simultaneous reduction of NOx and soot for direct injection diesel engine using high and low cetane fuels. The stratified injection system was applied for diesel engine to use high and low cetane fuel. In this study, diesel fuel was used as high cetane fuels, methanol was used as low cetane fuels. Some parts of the injection system, ie. Nozzle holder. delivery vale, was remodeled to inject dual fuel sequentially from one injector. The leak injection quantity ratio of dual fuel was certificated by volumetric ratio at injection quantity experiment. According as concentration of low cetane fuel was varied, combustion experiment was performed using Toroidal and Complex chamber. Also, exhaust gas and fuel consumption were measured at the same time. Simultaneous reduction of NOx and soot was achieved at complex chamber regardless of concentration of low cetane fuel. However, according as concentration of low cetane fuel was increased, THC and CO was increased.

• Journal of ILASS-Korea
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• v.1 no.2
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• pp.16-23
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• 1996

In case of a high-speed D.I. diesel engine. the injected fuel spray is unavoidable that the impinging on the wall of piston cavity and in this case the geometry of piston cavity has a great influence on the atomization structure and air flow fields. In the field of combustion and in many other spray applications, there are clear evidence of correlation between spray structure and emission of pollutants. Ordinary, the combustion chamber of driving engine have unsteady turbulent flow be attendant on such as the change of temperature, velocity and pressure. So the analysis of spray behavior is difficult. In this study, a single spray was impinged on each cavity wall at indicated angle in a quiescent atmosphere at room temperature and pressure, as being the simplest case, and 3 types of piston cavity such as Dish, Toroidal and Re-entrant type was tested for analyzing the influence of cavity geometry. And hot wire probe was used for analyze non-steady flow characteristics of impinging spray, and to investigate the behavior of spray, the aspects of concentration c(t), standard deviation $\sigma(t)$ and variation factor (v.f.) was measured with the lapse of time.

• Transactions of the Korean Society of Automotive Engineers
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• v.4 no.3
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• pp.211-219
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• 1996

In a small high-speed D. I. diesel engine, the injected fuel spray into the atmosphere of the high temperature is burnt by go through the process of break up, atomization, evaporation and process of ignition. These process are important to decide the emission control and the rate of fuel consumption and out put of power. Especially, in the case of injected fuel spray impinging on the wall of piston cavity, the geometry of piston cavity gives great influence the ignitability of injected fuel and the flame structure. Ordinary, the combustion chamber of driving engine have unsteady turbulent flow be attendant on such as the change of temperature, velocity and pressure. So the analysis of spray behavior is difficult. In this study, the spray was impinged on the wall of 3 types of piston cavity such as Dish, Toroidal, Re-entrant type, in order to analyze the combustion process of impinging spray precisely and systematically. And hot wire probe was used for analyze non-steady flow characteristics of impinging spray, and to investigate the behavior of spray, the aspects of concentration c(t), standard deviation σ(t) and variation factor(vf) was measured with the lapse of time.

• Journal of the Korean Society of Combustion
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• v.20 no.3
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• pp.13-20
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• 2015

The performance of a direct-injection diesel engine often depends on the strength of swirl or squish, the shape of combustion chamber, the number of nozzle holes, etc. This is natural because the combustion in the cylinder was affected by the mixture formation process. Since the available duration to make the mixture formation of air-fuel is very short, it is difficult to make complete mixture. Therefore, an early stage of combustion is violent, which leads to the weakness of noise and vibration. In this paper, the combustion process of a common-rail diesel engine was studied by employing two kinds of pistons. One has several cavities on the piston crown to intensify the squish during the compression stroke in order to improve the atomization of fuel, we call this multi cavity piston in this paper. The other is a toroidal single cavity piston, generally used in high speed diesel engines. To take photographs of flame and flaming duration, a four-stroke diesel engine was remodeled into a two-stroke visible single cylinder engine and a high speed video camera was used.