• Transactions of the Korean Society of Mechanical Engineers A
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• v.35 no.10
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• pp.1155-1160
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• 2011

High-strength nickel-based super alloys have been widely used in aircraft engines, vessel engines, and turbine blades because of their high strength and excellent fatigue and oxidation resistance. In this study, tests were carried out to determine the total strain range and temperature for high-strength nickel-based super alloys. Prepared specimens of IN738LC were exposed to temperatures of $871^{\circ}C$ and $982^{\circ}C$ for 1,000.10,000 h. These specimens were subjected to tests of mechanical properties and microstructure observations. The changes in mechanical properties were related to changes in ${\gamma}$ according to the thermal exposure time.

• Journal of Energy Engineering
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• v.6 no.2
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• pp.212-219
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• 1997

The objective of this study is to investigate the effects light diesel-water emulsified fuel on performance and exhaust emissions of the compression ignition engine. The experimental results of light diesel-water emulsified fuel operation with new type ultrasonic emulsification apparatus as compared with light diesel operation are very positive; maximum 28% reduction of SFC (in the case of 30% of water content), maximum 60% reduction of smoke (in the case of 30% of water content), maximum 79% reduction of CO emission (in the case of 30% of water content). However, comparing light diesel-water emulsified fuel and light diesel in the same engine under the same operating conditions, power and torque were lower in the case of emulsified fuel. In view of the results for the above mentioned, the mixing of water into light diesel in the form of emulsification proved to be the best means for reduction of specific fuel consumption and exhaust emissions of C.I. engines.

• Journal of the Korean Institute of Gas
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• v.16 no.3
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• pp.48-53
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• 2012

The purpose of this paper studies the failure cases including with system of liquefied phase injection in liquified petroleum gas vehicle. The first case, resulting with inspection the injector of LPG, it occasionally certified the injection damage phenomenon that the fuel efficiency(km/l) was decreased to 5% by carbon deposit with injector hole when the driver operates the vehicle. The second case, it certified the interference phenomenon of air flow with carbon deposit in ISA system control for idle speed of engine and throttle body suppling air into engine. As a result, the fuel efficiency was decreased 7%. The third case, the outer air during intake stroke was intermittently flowed in this gasket gap because of weaken adhesion power phenomenon for cylinder block by intake manifold gasket tearing. Consequentially, it certified the decrease for fuel efficiency to 3% by risen the amount of fuel injection as the air inflow quantity. These failure examples reduced the power performance of engine and the fuel efficiency of vehicle. It have to minimize of failure phenomenon preparing through quality management.

• Transactions of the Korean Society of Automotive Engineers
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• v.12 no.3
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• pp.51-58
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• 2004

Optimization of engine desist and operation parameters using a genetic algorithm was demonstrated for direct injection diesel engine combustion. A micro genetic algorithm and a modified KIVA-3V code were used for the analysis and optimization of the engine combustion. At each generation of the optimization step the micro genetic algorithm generated five groups of parameter sets, and the five cases of KIVA-3V analysis were to be performed either in series or in parallel. The micro genetic algorithm code was also parallelized by using MPI programming, and a multi-CPU parallel supercomputer was used to speed up the optimization process by four times. An example case for a fixed engine speed was performed with six parameters of intake swirl ratio, compression ratio, fuel injection included angle, injector hole number, SOI, and injection duration. A simultaneous optimization technique for the whole range of engine speeds would be suggested for further studies.

• Transactions of the Korean Society of Automotive Engineers
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• v.13 no.2
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• pp.101-107
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• 2005

In this paper, optimized operating parameters were found using multi-dimensional engine simulation software (KIVA-3V) and micro-genetic algorithm for heavy duty diesel engine. The engine operating condition considered was at 1,737 rev/min and 57 % load. Engine simulation model was validated using an engine equipped with a high pressure electronic unit injector (HEUI) system. Three important parameters were used for the optimization - boost pressure, EGR rate and start of injection timing. Numerical optimization identified HCCI-like combustion characteristics showing significant improvements for the soot and $NO_X$ emissions. The optimized soot and $NO_X$ emissions were reduced to 0.005 g/kW-hr and 1.33 g/kW-hr, respectively. Moreover, the optimum results met EPA 2007 mandates at the operating point considered.

• Electronics and Telecommunications Trends
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• v.23 no.6
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• pp.48-58
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• 2008

에너지 하베스팅 기술은 자연의 빛에너지, 인간 신체 또는 연소형 엔진으로부터의 저온 폐열에너지, 휴대용 기기 탑재/부착장치의 미세 진동에너지, 인간의 신체활동(걷거나 뛰는)으로 인한 소산에너지 등을 흡수하여 에너지 하베스팅 소자 기술을 이용하여 전기에너지로 변환, 전자 기기의 전력으로 사용하는 환경에너지 재생형 에너지원이라 할 수 있다. 유비쿼터스의 정보화 시대에는 휴대형 정보기기 등이 필수적인 기기가 될 것인데 여기에 사용되는 전력 에너지원은 소형.집적화된 기술이 필수적이다. 이때 MEMS 기술은 에너지 하베스팅 기술의 소형.집적화 기술에 크게 기여하고 극복해야 할 기술에 핵심적인 기술로 사용된다. MEMS 기술이 사용되는 대표적인 에너지 하베스터 기술인 마이크로 연료전지, 마이크로 히터 엔진, Piezoelectric MPG 기술 등을 소개하였다.

• Proceedings of the KSME Conference
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• 2001.06d
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• pp.31-36
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• 2001

As a part of micro engine development feasibility estimation was done through fabrication and test of down scaled combustor and MEMS fabricated spark electrode. In an experimental observation of the down scaled combustion phenomena where flame propagation was observed by optical method and pressure change in combustor which gives the information about the reaction generated thermal energy was recorded and analyzed. Optimal combustor scale was derived to be about 2mm considering increased heat loss effect and thermal energy generation capability. Through the fabrication and discharge test of MEMS electrode effects of electrode width and gap was investigated. Electrode was fabricated by thick PR mold and electroplating. From the result discharge voltage characteristic in sub millimeter scale electrode having thickness of $40{\mu}m$ was obtained. From the result base technology for design and fabrication of micro engine was obtained.

• Proceedings of the Korean Vacuum Society Conference
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• 2010.08a
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• pp.83-83
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• 2010

산업이 고도화되는 과정에서 에너지의 고효율화를 위하여 고온, 고압 등의 극한환경 하의 공정이 불가결하며, 이에 따라 초미세분진인 나노 입자가 증가되고 있다. 이에 따라 해당 나노의 입자 처리를 위하여 다양한 용도에서의 고온 필터가 산업적으로 요구되고 있다. 본 연구에서는 디젤엔진 매연저감 후처리 장치, 소각로, 발전소 등의 미세 분진 포집 필터로서의 응용을 위해, 카본 파이버에 SiC 휘스커를 증착하는 실험을 진행하였다. 휘스커 증착 공정은 촉매없이 SiC 휘스커를 카본 파이버 위에 화학증착하였다. 휘스커 성장 시 증착 조건의 변화를 통하여 다양한 휘스커의 증착 형태 및 미세구조를 관찰하였다. 또한 높은 포집 효율 및 기체투과도를 갖추기 위해, 휘스커가 증착된 시편의 포집효율 및 기체투과도 향상을 위한 실험을 진행하였다. 해당 실험의 결과로, 증착된 필터는 70% 이상의 포집효율을 보이면서도 기체 투과도는 현재 상용화되어 있는 코디얼라이트보다 5배 이상 높았다. 또한 필터에 추가적인 SiC 침윤공정을 통하여 시편의 내산화성, 내마모성, 내열성 등의 특성이 향상됨을 확인하였다.

• Journal of the Korean institute of surface engineering
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• v.29 no.1
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• pp.15-25
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• 1996

자동차엔진의 피스톤-링에 응용할 목적으로 플라즈마 용사 기술로 피막한 몰리부덴늄 및 코발트 합금 피막 층의 마모성질을 비교 조사하였다. Ball-on-disc 형태의 마모기를 사용하여 상온 및 대기 중에서의 마모 및 마찰거동에 대하여 조사하였다. 용사 층의 미세경도 시험도 행하였으며, 용사층의 결정구조를 알기 위해 용사층을 x-선 회절 방법으로 분석하였다. 주사전자현미경을 사용하여 마모면의 표면 형상을 관찰하였다. 여러 용사조건으로 만든 용사층의 미세경도치와 마모거동과의 상관관계를 이해하려고 시도하였다. 주사전자현미경과 EDX를 사용하여 마모시 화학반응층과 마모기구를 규명하고자 하였다. 모리부덴늄 및 코발트 합금 분말을 각각 플라즈마 용사층의 단면을 관찰하여 마모기구을 비교하였다.

• Journal of the Korean Society of Marine Environment & Safety
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• v.28 no.7
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• pp.1252-1258
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• 2022

The exhaust gas from the marine engines include a quantity of water vapor and particulate matter. The total particulate matter includes filterable particulate matter (FPM) and condensable particulate matter (CPM) that condense after releasing into the atmosphere. The portion of CPM is higher than that of FPM that is removable through the filter before discharging. An experimental setup for waste heat and water recovery and removal of CPM in the exhaust gas was tested using an industrial gas boiler in the laboratory. The water and CPM in the exhaust gas were removed through the first stage of cooling method and further removed through the second stage of absorption method. The efficiencies of water recovery were 73% after the first stage of cooling method and 90% after the second stage of absorption method. At the same time, the CPM was removed by 80-90% through the processes. The waste heat recovered could be used to process heat, and the water recovered could be used to process water in the ship. Furthermore, the CPM, which is a major source of the particulate matter but not subject to administrative regulation, could be removed effectively.