• Journal of ILASS-Korea
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• v.6 no.2
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• pp.22-28
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• 2001

Recently, many researches have been performed to improve the combustion and emission in a D.I.Diesel engine. Especially reduction of the soot formation in the combustion chamber is the essential to acquire the improvement of the emission performance. This emission of the diesel combustion is effected by the characteristics of air-fuel mixing. Therefore, the optical measurement technique such as LII and LIS were established in order to visualize the distribution of the soot and analyze the particle including spray in the combustion chamber. In this study, we developed the algorithm for calculating relative diameter and density of particle and applied this method to measure stimultaneously the distribution of soot and spray in a D.I. diesel engine. From this experiment we found that the soot is existed in the rich region of spray and generated caused by incapable air fuel mixture.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2012.05a
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• pp.1079-1080
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• 2012

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2011.11a
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• pp.579-583
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• 2011

The component based propulsion modeling and simulation of an air-breathing engine such as ramjet and scramjet is studied. The simulation model has been realized considering the characteristics of the air-breathing engine which is composed of air intake, combustor and nozzle including engine controller and fuel supply system. To estimate the engine performance and to verify the engine controller, real time based Hardware in the Loop System simulating actual environment is constructed.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.26 no.5
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• pp.724-732
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• 2002

Although the demands for diesel engine is increased, our world is faced with very serious problems related to the air pollution due to the exhaust emissions of the diesel engine. In this study, the potential possibility of oxygenated fuel such as Methyl tertiary butyl ether (MTBE) was investigated for the sake of exhausted smoke reduction from diesel engine. MTBE has been used as a fuel additive blended into unleaded gasoline to improve octane number, but the study of application for diesel engine was incomplete. Because MTBE includes oxygen content approximately 18%, it is a kind of oxygenated fuel that the smoke emission of MTBE is reduced remarkably compared with commercial diesel fuel, that is, it can supply oxygen component sufficiently at high load and speed in diesel engine. But, the NOx emission of MTBE blended fuel is increased compared with commercial diesel fuel. And. it was tried to analyze not only total hydrocarbon but individual hydrocarbon components from $C_1$to $C_{6}$ in exhaust gas using gas chromatography to seek the reason for remarkable reduction of smoke emission. The results of this study show three conclusions. 1. The smoke omission of the MTBE blended fuel is lower than that of the diesel fuel at all experimental region in direct injection diesel engine. 2. Individual hydrocarbons(C$_1$~ $C_{6}$) as well as total hydrocarbon of oxygenated fuel are reduced remarkably compared with diesel fuel. 3. Smoke emission from diesel engines was strongly depended on oxygen content in fuel regardless of operating condition.

• International Journal of Automotive Technology
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• v.6 no.3
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• pp.197-203
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• 2005

This paper investigates the effect of oxygen composition in mixed fuel on the exhaust emissions for the direct injection diesel engine. These effects were tested to estimate the change in engine performance and exhaust emission characteristics when commercial diesel fuel and oxygenates blended fuels at a certain fuel and mixed ratio are used. Individual hydrocarbons $(C_1-C_6)$ in exhaust gases, as well as the total amount of hydrocarbons, were analyzed by using gas chromatography to find the mechanism by which smoke emission was remarkably reduced for various oxygenated fuels. The chromatograms between a diesel fuel and a diesel fuel blended DGM (diethylene glycol dimethyl ether), MTBE (methyl tert-butyl ether) and EGBE (ethylene glycol mono-n-butyl ether) were compared. The results showed that the number of individual hydrocarbons as well as the total number of hydrocarbons of oxygenated fuel reduced more remarkably than those of diesel fuel.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.30 no.8
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• pp.120-125
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• 2002

In the preceding tests using the KSR-III Sub.(I) engines, it was observed that the heat resistant capability of the engines was not enough for the mission. So Sub.(I) Mod. engines were designed and tested. The Sub.(I) Mod. engines have three major design parameters - the arrangement of main injectors, the impinging angle of main injectors and thermal barrier coating. More than twenty experiments were carried on to evaluate engine performance and heat resistance capability with respect to design parameters. In this study, the test results are introduced. Analysing the result of Sub.(I) engine tests, it is found that decreasing the impinging angle, adopting the H-type arrangement(rather than radial type arrangement) and adopting the thermal barrier coating can increase heat resistance capacity substantially. Also, engine performance evaluation is conducted using specific impulse and characteristic velocity parameter. The results show that the performance variation is small(about 5%) and the performance is better in the case of radial arrangement. It is suspected that these phenomena are caused by the change of flame structure atomization mixing characteristic of sprays and the distortion of recirculation zone. Also from the low frequency instability point of view, it is observed that reducing the impinging angle and adopting the H type arrangement can increase the instability characteristics.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.3 no.4
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• pp.231-240
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• 1991

A design method has been developed for a Stirling engine with a tubular heater and cooler and a screen type regenerator. This paper provides a design procedure to determine the thermodynamic states and the geometric configurations of the Stirling engine for residential heat pumps. The major design is concerned with the working spaces, i.e. compression and expansion spaces and the heat exchangers such as the heater, the cooler and the regenerator. The Schmidt analysis has been employed to obtain the mass flow rates and heat transfer requirements of the system. The performance analysis of a model Stirling engine was performed by Martini-Weiss program to prove the validity of this design method. The results obtained indicate that this design method is valid for the Stirling engine conceptual design and performance analysis.

• International Journal of Automotive Technology
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• v.7 no.5
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• pp.519-526
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• 2006

For investigating the effect of fuel stratification on flame propagation, initial flame development and propagation were visualized under different axially stratified states in a port injection SI engine. Stratification was controlled by the combination of the port swirl ratio and injection timing. Experiments were performed in an optical single cylinder engine modified from a production engine and images were captured through the quartz window mounted in the piston by an intensified CCD camera. Firstly in this paper, the characteristics under no port-generated swirl condition, i.e. normal conventional case was studied. Under various stratified conditions, flame images were captured at the pre-set crank angles. These were averaged and processed to characterize the flames propagation. The flame stability was estimated by the weighted average of flame area and luminosity. The stability was also evaluated through the standard deviation of flame area and propagation distance, and mean absolute deviation of propagating direction. Results show that stratification state according to injection timing do not affect on the direction of flame propagation. The flame development and the initial flame stability are strongly dependent on the stratified conditions and the initial flame stability is closely related to the engine stability and lean misfire limit.

• Journal of Biosystems Engineering
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• v.32 no.6
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• pp.389-394
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• 2007

The power output of the stirling engine is influenced by the regenerator effectiveness. The regenerator effectiveness is influenced by heat transfer and flow friction loss of the regenerator matrix. In this paper, in order to provide basic data for the design of the regenerator matrix, characteristics of working fluid velocities were investigated by a packed method of matrix in the oscillating flow as the same condition of operation in a Stirling engine. As matrices, two different wire screens were used. The results are summarized as follows; 1. When a regenerator is not filled with any wire screen, working fluid velocity of the oscillating flow shows 1.3 times faster than that of one directional flow. 2. When a regenerator is filled with the wire screen of No.50, working fluid velocity of the oscillating flow reveals 2.5 times faster than that of one directional flow. 3. When a regenerator is filled with the wire screen of No. 100, working fluid velocity of the oscillating flow shows 2 times faster than that of one directional flow, regardless of the number of packed wire screens. 4. Working fluid velocity is decreased wire the increase in number of meshes and packed wire screens.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.26 no.3
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• pp.498-506
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• 2002

Improvements of fuel properties have become essential for exhaust emission reduction as well as for optimization of directly-related design factors and exhaust gas aftertreatment. In this study, the potential possibility of oxygenated fuel such as ethylene glycol mono-n-butyl ether(EGBE) was investigated for the sake of smoke reduction from diesel engine. Because EGBE include oxygen content approximately 27%, it is a kind of effective oxygenated fuel that the smoke emission of EGBE is reduced remarkably in comparison with commercial diesel fuel, that is, it can supply oxygen component sufficient at high load and speed in diesel engine. And, it was tried to analyze the quantities of the low and high boiling point hydrocarbon among the exhaust emissions in diesel engine. It have been investigated by the quantitative analysis of the hydrocarbon $C_1$~ $C_{6}$ using the gas chromatography. This study was carried out by comparing the chromatogram with diesel fuel and diesel fuel blended EGBE 20vo1-%. The results of this study show that the hydrocarbon $C_1$~C$_{6}$ among the exhaust emission of the mixed fuels are exhausted lower than those of the diesel fuel at the all load and speed. In particular, high boiling point hydrocarbons such as $C_{5}$ and $C_{6}$ were reduced remarkably at high speed and load.d.