• 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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• 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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• 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.

• 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.

• 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.

• 한국자동차공학회논문집
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• 제5권3호
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• pp.147-158
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• 1997

This paper presents the analysis technique and procedure of main engine components-cylinder block, cylinder liners, gasket and cylinder head-using the finite element method, which aims to assess mainly the potential of lower oil consumption in a view point of engine design and to decide subsequently the accuracy of engine design which was done. The F.E. model of an engine section consisting of one whole cylinder and two adjacent half cylinders is used, whereby the crankcase is cut off at the block bottom deck. By means of a 3-dimensional F.E. model-including cylinder block, liners, gasket, cylinder head, bolts and valve seat rings as separate parts a linear analysis of deformations and stresses was performed for three different loading conditions;assembly, thermal and gas loads. For the analysis of thermal boundary conditions also the temperature field had to be evaluated in a subsequent step.

• 오토저널
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• 제12권4호
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• pp.66-74
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• 1990

Friction between piston-ring assembly and cylinder wall of a spark ignition engine was evaluated under various engine operating conditions utilizing a grasshopper linkage system. The friction force was estimated by the force balance relation at the small end of connecting rod. Three forces were chosen to be measured for the objective. They were gas pressure inside the cylinder, inertia force of the piston-ring assembly, and the force exerted by the connecting rod. These forces were measured by a piezo type pressure sensor, an accelerometer and strain gauges, respectively. Comparisons were made with the frictional force evaluated by the conventional method where the assumption of constant rotational speed of engines was adopted. Due to the variation of rotational speed of engines, the conventional method was found to lead to a large error in the evaluation of the frictional force.

• 한국자동차공학회논문집
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• 제2권3호
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• pp.94-104
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• 1994

In order to improve engine performance and its reliability it is very important to find the friction force between piston-ring assembly and cylinder wall in engine operating conditions. A new system was developed for the piston-ring assembly friction force measurement. This system had a relatively high fundamental frequency at 884 Hz and a fine resolution of 0.5N in friction force measurement. Comparing with existing floating liner systems this systems required small installation space and at the same time alleviated the system noise problem induced by the thrust and slap impulse forces.

• Composites Research
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• 제20권3호
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• pp.63-66
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• 2007

Structural analysis of automotive engine cover under vibration excitation is performed by finite element analysis (FEA) in order to identify the critical area of the structure. Assembly load due to the tightening of the bolts as well as the vibration excitation were considered to describe the actual loading condition. Natural frequencies of the system were extracted considering the damping effect of the structure. Dynamic analysis was performed based on the extracted natural frequency of the system. Experimental modal analysis (EMA) and measurement of strains were performed to verify the results of the analysis. Analysis results correlated closely with the experimental results. Analysis and experiments showed that contribution of the assembly load should not be ignored to predict the structural failure of the engine cover.

• 한국시뮬레이션학회논문지
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• 제19권2호
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• pp.107-118
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• 2010

자동차 제조업은 수천 가지의 다른 구성품 또는 부품의 조립이 필요한 복잡한 생산시스템이다. 엔진과 트랜스미션은 자동차의 동력을 담당하는 주요 구성품이다. 엔진의 경우 생산공정이 대부분 유사한 공정들로 구성되어 있음에도 불구하고 공장별로 생산시스템의 배치안은 상이하다. 그 이유는 각 공장마다 기계들을 어떠한 직렬구조와 병렬구조를 조합하여 배치하는지에 대한 개념이 다르기 때문이다. 이 논문에서는 서로 다른 공장에서 적용하고 있는 세 종류의 엔진 라인을 소개한다. 그리고 시뮬레이션을 이용하여 각 라인의 설계개념이 라인의 성과에 미치는 영향에 대해 비교분석하고자 한다.