• Transactions of the Korean Society of Mechanical Engineers B
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• v.33 no.12
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• pp.952-960
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• 2009

Selective Catalytic Reduction (SCR) system is a high-effective NOx reduction technology in diesel engines. As the emission standard of diesel engines is more stringent, vehicle manufactures makes efforts on emission technologies. This paper discusses the performance of Urea-SCR system according to the engine operating conditions in a passenger diesel engine. Engine test results in this paper show that it is important to consider the catalyst temperature and space velocity to obtain high NOx conversion efficiency. In condition of high catalyst temperature, over 90% NOx conversion efficiency is indicated. However, when catalyst temperature is low, NOx conversion efficiency was decreased. Also, it was shown that space velocity mainly effects on the DeNOx performance under 220 degree celsius of SCR catalyst temperature. As the urea injection pressure was decreased, NOx conversion efficiency was declined. It is concerned about urea droplet atomization. This work shown in this paper can lead to improved overall NOx conversion efficiency.

• Journal of Advanced Marine Engineering and Technology
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• v.38 no.1
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• pp.23-30
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• 2014

To improve efficiency of diesel engine which requests high output recently and is used all kinds of industrial areas, this thesis experimented dynamic characteristics and exhaust gas characteristics of diesel engine installed by supercharger of correspondent output 200HP and natural inhalation diesel engine through the dynamometer and exhaust gas analyzer in same condition. As the result of experiment with natural inhalation diesel engine and diesel engine installed by supercharger, there were a few differences of output, but dynamic characteristics at high speed showed increased output and efficiency of the engine installed by supercharger. On the contrary, in exhaust gas characteristics, the model installed by supercharger showed increased exhaust gas such as $NO_X$, $O_2$, etc, but added value of exhaust gas is low if considering $CO_2$ reduction and efficiency of dynamic characteristic's increase. Based on the results, diesel engine installed by supercharger is expected to show higher economic feasibility than natural inhalation diesel than natural inhalation engine from an angle of efficiency. Keywords: 200hp class Turbocharger, Exhaust Gas, Engine Performance, Marine Diesel Engine.

• Journal of the Korean Society of Propulsion Engineers
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• v.7 no.4
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• pp.63-72
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• 2003

The combustion characteristics of the KSR-III engine were investigated numerically from the viewpoint of performance and combustion field. For numerical analysis of KSR-III engine with hub-and-spoke baffle, 3-D calculation was performed about $30^{\cire}$ section and the prediction of performance was in a good agreement with hot-firing test result. As a result of baffle installed, the performance of KSR-III engine was reduced in comparison with no baffle case and local high temperature region appeared on injector plate, combustion wall and baffle wall, This calculation was used practically as basic data for designing injector plate with film cooling holes and predicting the performance of KSR-III final flight test.

• Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
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• 1998.04a
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• pp.3-43
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• 1998

Technical and business transformations are reshaping the business of Diesel engine builders, Diesel lubricant marketers and additive companies. Key issues facing engine builders and end users under these transformations include: -Emission regulations -Vehicle operating costs -Evolving business environments With these challenges come opportunities. For equipment builders and lubricant marketers, these include: -Lubricants meeting global performance requirements -High value lubricant applications -Profitable new businesses

• Transactions of the Korean Society of Automotive Engineers
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• v.10 no.6
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• pp.11-18
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• 2002

Residual gas fraction in an engine cylinder affects engine performance, efficiency and emission characteristics. With high residual gas fractions, a flame speed and maximum combustion temperature are decreased and these are deeply related with combustion stability especially at idle and NOx emission at relatively high engine load. In this work, the residual gas fraction was calculated by an engine simulation code, which was validated by the experimental data (cylinder pressure and emissions) obtained from 4-cyliner spark ignition engine. A comparison between experimental and computational calculation results was made. The residual gas is generated mostly at low engine speed by the larger pressure difference between the intake and exhaust port. As the valve overlap duration was increased, the amount of residual gas in the cylinder, the amount of HC emission in the exhaust gas and the variation of power output increased.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2004.03a
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• pp.314-317
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• 2004

On 9/5/2003, the planet probe “HAYABUSA” as MUSES-C project was launched by The Institute of Space and Astronautical Science. “HAYABUSA” has microwave discharge ion engines and these engines are characterized by their high efficiency and specific impulse in comparison with chemical engine. A large ion engine can be used as a planet explorer, while a small ion engine can be used as attitude control of small satellite. We have been developing a high thrust density microwave discharge ion engine using “Multi-Monopole Antenna”. The performance of this engine are: ion cost of 344W/A, propellant utilization efficiency of 52% and thrust density of 0.055mN/$\textrm{cm}^2$ for Kr gas flow rate of 2.5sccm, microwave(2.45㎓) power of 32W and acceleration voltage of l.4㎸.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2009.05a
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• pp.414-416
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• 2009

In order to build a transient simulation program for a high thrust liquid rocket engine(LRE), a static performance simulation program for components were made. The components were the thrust chamber (combustion chamber and supersonic nozzle), centrifugal pump (impeller and volute casing), impulse turbine, and flow control devices (control valve and orifice). Simplified mathematical models based on classical thermodynamic and inviscid theories were used to remove complexity and enhance the utility of the program. We examined the results of each program qualitatively for validate each component modeling.

• Transactions of the Korean Society of Automotive Engineers
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• v.24 no.6
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• pp.619-626
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• 2016

The new 1.4 L turbocharged LPG direct injection (T-LPDI) engine is presented in this paper to improve the fuel efficiency of the vehicles installed with the 2.0 L LPG port fuel injection (LPI) engine, while maintaining the performance as a downsizing concept for the new engine platform development. Firstly, the return type high pressure LPG fuel supply system is designed and mounted in the new 1.4 L T-LPDI engine. As a result, this new engine shows a much better WOT performance and approximately 8 % of improved fuel economy level, as compared to the 2.0 L LPI vehicle. Secondly, the LPDI engine specific optimized design for high pressure fuel components and fuel injection control strategies are proposed and evaluated in order to overcome the restartability problem in a heat-soaked condition called the vapor lock phenomenon. Consequently, these experimental results illustrate a great potential for the developed 1.4 L T-LPDI engine as a possible substitute for the 2.0 L LPI engine.

• Journal of the Korean Society of Industry Convergence
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• v.19 no.1
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• pp.31-38
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• 2016

Since the oil shock of 1970's there was a strong upward tendency for the use of the high viscosity and poorer quality fuels. Therefore the misfiring engine occurs due to the decrease of quantity injected for lean burn and emission control in Compression Ignition Common Rail Direct Injection diesel engine. In this study, it is designed and used the test bed which is installed with fuel injector controller. In addition to equipped engine using CRDI by controlling the injection timing with mapping modulator, it has tested and analyzed the engine performance and combustion characteristics, as it is varied that they are the operating parameters: fuel injected quantity, engine speed and injection timing.

• Transactions of the Korean Society of Automotive Engineers
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• v.19 no.2
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• pp.105-110
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• 2011

Through this study, the performance evaluation on the addition of low-pressure loop EGR(Exhaust Gas Recirculation) in a 6.0 L commercial diesel engine was carried out using WAVE modeling and simulation. Since the key technology of advanced diesel engine combustion such as low-temperature combustion is to steadily supply high rates of EGR in a wide operating range, the current study could be effectively contribute to the design and development processes of up-to-date diesel engine systems as real-world reference data. The current simulation results show that the system in which low-pressure loop EGR is added shows almost 2.3 times increase in maximum EGR rate at 1000 rpm as well as almost 1.6 times increase at 2200 and 1600 rpm in comparison with an engine system employing high-pressure loop EGR only. Also, both turbocharger axis speed and charging pressure level did not deteriorate due to the addition of low-pressure loop EGR at 2200 and 1000 rpm, but they were fairly decreased at 1600 rpm.