• 한국추진공학회지
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• 제8권4호
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• pp.102-108
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• 2004

고성능 액체로켓엔진 개발을 위하여 터보펌프를 사용하는 재생냉각형 액체로켓엔진시스템의 배치안을 마련하였다. 엔진시스템을 구성하는 부품들에 대하여 각각의 특성을 고려하고 현실적으로 제작 및 조립이 가능하도록 3차원 디지털 모형을 제작하여 검증하였다. 1단 엔진시스템은 1축 김벌링을 하며 4개의 엔진 조립체로 클러스터링할 수 있도록 설계하였다. 2단용 엔진시스템은 2축 김벌링을 하며 1개의 엔진 조립체로 구성하였다. 1단 및 2단 엔진시스템의 조립 및 분해 공정 그리고 관련 프로그램 또한 개발하였다. 그리고 엔진시스템의 조립 및 분해 공정을 효율적으로 수행하기 위하여 여러 형태의 전용 치/공구 또한 설계하였다.

• 한국추진공학회:학술대회논문집
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• 한국추진공학회 2004년도 제23회 추계학술대회 논문집
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• pp.162-165
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• 2004

고성능 액체로켓엔진 개발을 위하여 터보펌프를 사용하는 재생냉각형 액체로켓엔진시스템의 배치안을 마련하였다 엔진시스템을 구성하는 부품들에 대하여 각각의 특성을 고려하고 현실적으로 제작 및 조립이 가능하도록 3차원 디지털 모형을 제작하여 검증하였다. 1단 엔진시스템은 1축 김발링을 하며 4개의 엔진 조립체로 클러스터링 할 수 있도록 설계하였다. 2단용 엔진시스템은 2축 김발링을 하며 1개의 엔진 조립체로 구성하였다. 1단 및 2단 엔진시스템의 조릴 및 분해 공정 그리고 관련 프로그램 또한 개발하였다. 그리고 엔진시스템의 조져 및 분해 공정을 효율적으로 수행하기 위하여 여러 형태의 전용 치/공구 또한 개발하였다.

• 대한기계학회논문집A
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• 제26권11호
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• pp.2429-2435
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• 2002

The aim of this paper is to investigate the problem of strip down method, which is usually used to evaluate the engine friction level. The validity of strip down method was investigated by theoretical analysis of friction in crank and piston assembly. The friction of cylinder and piston assembly was analyzed under the various test conditions. The measured cylinder pressure was used as boundary conditions of friction torque and loss calculation. The friction loss of crank and piston assembly was influenced by test conditions that resulted from the variation of load condition. From the results, we have known that the strip down method could be possible to distort the friction loss of engine moving components.

• 한국자동차공학회논문집
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• 제3권2호
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• pp.77-85
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• 1995

Among mechanical friction losses in an engine, the piston assembly and cylinder components accounts for the majority of the losses. The movable bore technique has been developed and turned out to be the most reliable technique in measuring the instantaneous friction of piston assembly. The weakness of this system, however, was the presence of the protruded top of movable bore necessary for pressure balancing. Because of the protruded part the piston could not be taken out without disassembling the crankshaft. Present study was carried out with a system of removable top of the movable bore so that it was possible to make frequent piston removals. The effects from engine speed, oil viscosity, engine load and elastic contact pressure of piston rings on the frictional characteristics have been evaluated with the improved equipment. Also, frictions of each member of piston assembly were measured.

• 한국자동차공학회논문집
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• 제24권4호
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• pp.416-424
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• 2016

A robust design of head gasket is pursued by using FEA model of engine assembly. Engine assembly model consists of cylinder head, block, gasket, and head bolt is constructed to understand a complex behavior of this engine compound. Thermal loading is performed on the assembled engine cylinder and block to obtain temperature field. Firing load is added to the results of heat transfer analysis to simulate the engine operation condition. Temperature filed results from heat transfer analysis are mapped into the structural mesh. Contact pressure distribution along the bead has been monitored for the engine operation condition. Based on the results obtained from the analysis, Taguchi method has been adopted for a robust design process of head gasket. Among the control factors, bolt size affects most robustness of head gasket sealing.

• 한국자동차공학회논문집
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• 제14권1호
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• pp.31-38
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• 2006

Cylinder liner rotation is a new concept for reducing piston assembly friction in the internal combustion engine. The purpose of cylinder liner rotation is to reduce the occurrence of boundary and mixed lubrication friction in the piston assembly. This paper reports the results of experiments to quantify the potential of the rotating liner engine. A GM Quad-4 SI engine was converted to single cylinder operation and modified for cylinder liner rotation. The hot motoring method was used to compare the friction loss between the baseline engine and the rotating liner engine. Additionally, tear-down tests were used to measure the contribution of each engine component to the total friction torque. The cycle-averaged motoring torque of the RLE represents a $23\~31\%$ friction reduction compared to the baseline engine for hot motoring tests. Through tear down tests, it was found that the piston assembly friction of the baseline engine is reduced from $90\%$ at 1200 rpm to $71\%$ at 2000 rpm through liner rotation.

• 한국자동차공학회논문집
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• 제12권1호
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• pp.122-129
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• 2004

Finite element analysis was performed to analyze structural safety of a new heavy-duty direct injection diesel engine. A half section of the in-line 6-cylinder engine was selected as a computational domain. A mapping method was used to project heat transfer coefficients from CFD results of engine coolant flow onto the FE model. The accurate setting of thermal boundary condition on the FE model was expected to result in improved prediction of temperature, cylinder bore distortion, and stresses. Characteristics of high cycle fatigue were investigated by assuming the engine was operated under the following five loading conditions repeatedly; assembly force, assembly force with thermal loading, alternating maximum gas pressure loading at each cylinder combined with assembly force and thermal loading. Distribution of fatigue safety factor was calculated by using it Haigh diagram in which the maximum and the minimum stresses were selected from the five loading cases.

• 대한기계학회논문집A
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• 제35권8호
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• pp.965-970
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• 2011

본 연구를 통하여 개발하고자 하는 진단시스템은 자동차 엔진 어셈블리라인에서 발생될 수 있는 특정 조립 불량유형을 검사하는 시스템이다. 대상으로 하는 불량 유형은 엔진 고장의 유형 중 커다란 충격성신호가 발생한 후, 보상적인 작은 충격파가 주기적으로 발생되는 형태이다. 이러한 불량유형을 기존의 시간영역분석 진단, 주파수분석, 통계적분석등에 의해 진단할 경우 한계점이 존재한다. 이에 웨이블릿 잡음 제거 전처리 방법, 피크검지 알고리즘, 불순도 최소값 선택 분할 방법을 이용한 새로운 유형의 이상진단 방법을 개발하는 연구를 진행하였다.

• 산업융합연구
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• 제18권1호
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• pp.17-23
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• 2020

본 연구는 블렌디드 러닝을 위한 자동차 엔진 부품 조립에 대한 증강현실 콘텐츠 개발을 하고 설문을 통해 교육 효과의 유용성을 확인하였다. 자동차 엔진 조립에 대한 커리큘럼을 설계하고, 각 커리큘럼에 따라 조립해야 할 부품의 모양, 위치, 조립 순서 등을 증강현실 콘텐츠로 개발하였다. 개발된 증강현실 시뮬레이션 콘텐츠는 학습자 중심의 협력 활동과 결합하여 학생들이 능동적으로 학습할 수 있도록 하였고, 교사는 촉진자 역할을 수행하도록 설계하였다. 본 콘텐츠와 전통적인 학습을 한 학생들과 비교 실험하여 약 2배의 학습 시간이 절감되는 것으로 나타났다. 본 연구를 통해 학생들의 문제해결, 프로세스 기술, 시스템 기술 및 인지 능력 등이 강화되는 것을 확인할 수 있었다.

• 대한기계학회논문집
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• 제18권6호
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• pp.1510-1519
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• 1994

It is important to understand the friction characteristics between piston-ring assembly and cylinder wall for the friction loss reduction as well as the solution of problem such as scuffing wear and oil consumption. A new system was developed for the piston-ring assembly friction force measurement. This system was applied to the friction force measurement to find its functional relationship with variables such as engine speed, oil viscosity, and engine load. The friction mean effective pressure(fmep) was found to have a linear relationship with$(\vpsilon{U})^{0.42}$ under motering and with$(\vpsilon{U})^{0.45}$ under firing operations, where $\vpsilon$ is the kinematic oil viscosity and U is mean piston speed.