• Transactions of the Korean Society of Automotive Engineers
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• v.22 no.1
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• pp.193-201
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• 2014

A numerical study has been carried out to analyze the combustion characteristics in heavy duty diesel engine with post injection for reducing NO emission. For verification of numerical study results, calculated cylinder pressure was matched to experimental data. In this study, post injection timing and amount of post injection were modified as parameters, but the total amount of injection fuel was maintained. As the results, maximum cylinder pressure increases above minimum 2% by post injection and end of pressure curve is decreased rapidly. The more dwell time and amount of post injection fuel are, the more pressure drop occurs. And trade-off relation of NO and soot are appeared. In the results, NO was reduced without deterioration of cylinder pressure under condition of $10^{\circ}$ CA dwell time and main 60%, post 40% fuel portion.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.28 no.1
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• pp.59-65
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• 2004

The configuration of intake port and piston is a dominant factor of inlet air flow and mixture formation in an engine cylinder, resepectively. This study has analyzed intake port and piston characteristics for swirl flow of a heavy-duty LPG engine. As an available technology to optimize intake port, the steady flow rig test has been applied for measuring swirl ratio and mean flow coefficient. And we measured the mean velocity and turbulence intensity of swirl flow under motoring condition in transparent engine cylinder by backward scattering LDV system. From these results, the piston and cylinder head with a good evaluated swirl flow characteristics were developed and adapted fur a 11L heavy-duty engine using the liquid phase LPG injection (LPLI) system. The obtained results are expected to be a fundamental data for developing intake port and piston.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.32 no.5
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• pp.402-410
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• 2008

The heavy duty diesel engine must have a large output for maintaining excellent mobility. In this study, a three dimensional finite element model of a heavy-duty diesel engine was developed to conduct the stress analysis. The FE model of the heavy duty diesel engine main parts consisting with four half cylinder was selected. The heavy duty diesel engine parts includes with cylinder block, cylinder head, gasket, liner, bearing cap, bearing and bolts. The loading conditions of engine were pre-fit load, assembly load, and gas load. As the results of structural analysis, because the stress values of cylinder block and bearing cap did not exceed the basic design can be satisfied. But on the part which contacts with cylinder block and bearing cap the stress value exceeds the allowable strength of material. In order to decrease the stress at that part, it was optimized with parametric study.

• Transactions of the Korean Society of Automotive Engineers
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• v.23 no.2
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• pp.178-184
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• 2015

According to the regulation on the environment and fuel efficiency is becoming strict, many experiments are conducted to improve efficiency and emission in internal combustion engines. LTC (Low temperature combustion) technology is a promised solution for low emissions but there are a few barriers for the commercial engine. This paper includes optimization that applies LTC method to heavy duty diesel engine. Adequate LTC was applied to low and middle load as adaptability in heavy duty diesel engine, and optimization focused on reduction of fuel consumption was proceeded at high load. Through this research, strategy for practical use of LTC was selected, and fuel consumption has improved on the condition that satisfies the emission regulation at systematic viewpoint.

• Transactions of the Korean Society of Automotive Engineers
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• v.14 no.1
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• pp.115-122
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• 2006

EGR system has been widely used to reduce NOx emission in light duty diesel engines, but its application to heavy duty diesel engine is not common yet. In this study, simulation model for EURO-3 engine was developed using commercial code WAVE and then verified by comparison with experimental results in performance and emission. Possibility to meet EURO-4 regulation using modified EURO-3 engine with LPL EGR system was studied. Each components of the engine was modeled using CATIA and WaveMesher. The engine test mode was ESC 13 and injection timing and quantity were changed to compensate engine performances, because applying EGR causes power reduction. As a results of the simulation, it was found that EURO-4 NOx regulation could be achieved by applying LPL EGR system to current EURO-3 engine even with some BSFC deterioration.

• Journal of the Korean Institute of Gas
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• v.27 no.3
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• pp.91-97
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• 2023

Aging construction machinery and vehicles with old diesel engines usually have a long life span, so they continue to emit harmful emissions. Therefore, replacing these older diesel engines with engines that meet the latest emisstion standard is expected to help improve air quality, and engines with propane fuels, which are easily available at construction sites, can be an appropriate alternative. In this study, a propane fueled engine was developed based on a 6.8-liter CNG engine, and technologies such as gas injectors, exhaust gas recirculation (EGR), and enhanced catalysts were applied. As a result, nitrogen oxides achieved half of the emission performance at the Stage-V level, the latest emission standard, while securing diesel engine output and torque in the same class.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2009.11a
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• pp.608-612
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• 2009

Technology demonstration models(TDM) of a 75-$ton_f$ liquid rocket engine(LRE) thrust chamber were manufactured on the basis of development technologies of 30-$ton_f$ LRE. It was confirmed that some machining and welding technologies which were aimed to be verified through the manufacturing of demonstration models could be applied to the thrust chamber 75-$ton_f$-class. New designed mixing head part was manufactured by means of new process. The manufacturing process and technologies established through TDM's will improve the reliability of manufacturing process of large LRE thrust chamber.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2009.11a
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• pp.125-129
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• 2009

The basic design of liquid rocket engine combustion chamber for a large space launch vehicle was described. It has vacuum thrust of 74.8 ton, vacuum specific impulse of 306.9 sec, chamber pressure of 60 bar, mass flow rate of 243.6 kg/s and combustion characteristic velocity of 1730 m/sec. The details of combustion performance and geometrical parameter were also given. The 75 ton combustion chamber consists of the combustor head with injector and the chamber/nozzle with regenerative cooling channels.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2017.05a
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• pp.188-193
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• 2017

USA and Europe are leading a transport airplane industry. In Asia-Pacific region, air transportation and MRO industries are forecasted to be grown up rapidly. Furthermore, Japan and China entered into design and manufacture state of regional airplane, and developing countries entered into severe struggle competition for MRO industry. Global aircraft MRO and engine MRO industries are forecasted 3.4% and 7% growth respectively in next decade. In this paper, authors propose promotion strategy for technology intensive MRO of aircraft engine to create a higher value-added business.

• Journal of the Korean Society of Propulsion Engineers
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• v.22 no.4
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• pp.117-124
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• 2018

USA and Europe are leading the transport airplane industry. In Asia-Pacific region, air transportation and MRO industries are forecasted to be grown up rapidly. Furthermore, Japan and China entered into design and manufacture state of regional airplane, while developing countries entered into severe struggle competition for MRO industry. Global aircraft MRO and engine MRO industries are forecasted 3.4% and 7% annual growth respectively in the next decade. In this paper, authors propose promotion strategy for technology intensive MRO of aircraft engine to create a higher value-added business.