• 한국소성가공학회:학술대회논문집
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• 한국소성가공학회 1996년도 자동차부품 제작기술의 진보
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• pp.35-46
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• 1996

The powder forging process offers beneficial material utilization as well as the minimization of finishing operations over that of conventionally forged rods. In the present work, the sintering behavior of Fe-2Cu-0.6C-0.35MnS, optimum preform design and forgeability of various forging conditions were investigated. This data were generated using a newly proposed sub-scaled con-rod specimen developed specifically to simulate the powder forging process. The results of present work, powder perform is so difficult to flow material into die cavity and mass flow has no effect on improving the strength. And, applied force to increase density of the specimen flowed material is greater than that of all repessing mode. On the contrary, the specimen flowed material became increased hardness of inside in contrast with all repressing mode, but the tensile strength were decreased with residual porosity in surface. Due to material flow characteristic of powder preform, the section of lower density in powder preform became also lower density in forged con-rod. So, preform design is very important in manufacturing powder forged connecting rod.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2005년도 창립60주년 기념 추계 학술대회
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• pp.125.2-125.2
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• 2005

• 한국윤활학회:학술대회논문집
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• 한국윤활학회 1993년도 춘계학술대회 및 공장견학
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• pp.39-53
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• 1993

The minimum oil film thickness(MOFT) in the connecting-rod bering of a 1.5 liter, L-4, gasoline engine is measured up to 5500 rpm and calculated to study the dynamically loaded engine bearing. Short bearing approximation and Mobility method are used for theoretical analysis of oil film charactrtistics. And cylinder pressure, crank-pin surface temperature and bearing tenp ture are measured as the input data of theoretical analysis. The MOFT are measured by the total capacitance method(TCM). To improve the reliability of the test results, a reasonable detmuuination method of bearing clearance is introduced and used, and the effects of cavitation and aeration on the test results are neglected. The crankshaft is grounded by means of a slip ring. A scissor type linkage system was developed to measure the MOFT and bearing temperature. The effects of engine speed, load and oil viscosity on the measured and calculated minimum oil film thicknesses are investigated at 1500 to 5500 rpm. From the comparison between the measured and calculated MOFT, it is found that a qualitative similarity exists between them, but in all cases, the measured MOFT are smaller than those calculated.

• Tribology and Lubricants
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• 제10권1호
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• pp.14-26
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• 1994

The minimum oil film thickness(MOFT) in the connecting-rod bearing of a 1.5 liter, L-4, gasoline engine is measured up to 5500 rpm and calculated to study the dynamically loaded engine bearing. Short bearing approximation and Mobility method are used for theoretical analysis of oil film characteristics. And cylinder pressure, crank-pin surface temperature and bearing temperature are measured as the input data of theoretical analysis. The MOFT are measured by the total capacitance method(TCM). To improve the reliability of the test results, a reasonable determination method of bearing clearance is introduced and used, and the effects of cavitation and aeration on the test results are neglected. The crankshaft is grounded by means of a slip ring. A scissor type linkage system was developed to measure the MOFT and bearing temperature. The effects of engine speed, load and oil viscosity on the measured and calculated minimum oil film thicknesses are investigated at 1500 to 5500 rpm. From the comparison between the measured and calculated MOFT, it is found that a qualitative similarity exists between them, but in all cases, the measured MOFT are smaller than those calculated.

• 한국자동차공학회논문집
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• 제13권6호
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• pp.154-162
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• 2005

This study investigates the fatigue life and the damage possibility of connecting rod by the fatigue tool of Ansys workbench. The case of constant fatigue loading variation 'Sine' becomes more stable than that of nonconstant loading but the magnitude of constant load becomes larger than that of nonconstant load. Among nonconstant fatigue loads, the case of 'SAE Bracket History' which is severest at the variation of load tends to be most unstable. The case of 'Sample History2' which becomes a little slow at the variation of load tends to be most stable. The maximum relative damage in case of 'SAE Bracket History' is occurred near the average stress '0' and this case can be shown to have the possibility to take more damage than another case.

• Tribology and Lubricants
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• 제38권6호
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• pp.227-234
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• 2022

Recently, the demand for improving energy efficiency has rapidly increased because of the growing concerns over environmental issues. In this work, the tribo-test and simulation for the initial wear and lubrication performance were performed for the piston pin in the small end system of the connecting rod of a marine engine, to obtain useful data for improving the efficiency of marine engine systems. In addition, a diamond-like carbon (DLC) coating was applied to the piston pin to explore feasibility of eliminating the bush used in the system. The initial wear and lubrication characteristics between the uncoated piston pin and bush were compared with that between the DLC-coated piston pin and connecting rod in the tribo-test. The simulation for the wear and lubrication performance according to the wear progression was conducted based on the data obtained from the test. The wear characteristics were quantitatively assessed by the wear depth and wear volume, and the lubrication performance was characterized with the change of pressure and minimum oil film thickness with respect to the crank angle. It was found that the DLC-coated piston pin may provide better initial wear characteristics and lubrication performance. The results of this work may provide fundamental information for marine engines with improved efficiency.

• 소성∙가공
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• 제20권3호
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• pp.236-242
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• 2011

The two objectives of this study were, first, to determine the optimal friction welding process parameters using finite element simulations and, second, to evaluate the mechanical properties of the friction welded zone for large piston rods in marine diesel engines. Since the diameters of the rod and its connecting part are very different, the manufacturing costs using friction welding are reduced compared to those using the forging process of a single piece. Modeling is a generally accepted method to significantly reduce the number of experimental trials needed when determining the optimal parameters. Therefore, because friction welding depends on many process parameters such as axial force, initial rotational speed and energy, amount of upset and working time, finite element simulations were performed. Then, friction welding experiments were carried out with the optimal process parameter conditions resulting from the simulations. The base material used in this investigation was AISI 4140 with a rod outer diameter of 280 mm and an inner diameter of 160 mm. In this study, various investigation methods, including microstructure characterization, hardness measurements and tensile and fatigue testing, were conducted in order to evaluate the mechanical properties of the friction welded zone.

• 오토저널
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• 제14권2호
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• pp.110-119
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• 1992

Crank pin temperatures were measured and analyzed to find out practical method which can predict the engine bearing reliability. The measuring points were determined to be near the MOFT region and far from that by theoretical calculation. The effect of engine running condition, oil temperature, the change of oil circuit into bearing and crankshaft endplay on crank pin temperature were experimentally tested. The result obtained was as following. The crank pin temperature was dependent on oil film thickness and directly influenced by the change of test condition. Also, the length of the crankshaft endplay was confirmed to be critical to connecting rod bearing failure. In conclusion, we found that the measurement method of crank pin temperature can be used for predicting the engine bearing reliability.

• 센서학회지
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• 제18권5호
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• pp.393-401
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• 2009

This paper describes development of a new displacement sensor for intelligent suspension system in which the damping force has been controlled by MR fluid. Most of the current vehicle height sensors have been installed at external place of the damper and connected to that by mechanical linkages so far. The developed sensor has a new mechanism which detects movement of the sensor rod same as connecting rod in the suspension damper by using a GMR Sensor and converts it to the relative displacement from an initial position.

• 오토저널
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• 제7권1호
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• pp.63-67
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• 1985

KIA는 호평의 Bongo-9을 기본 model로 하여 도시형 다목적 leisure car인 Bongo-town을 개 발하게 되었다. TX엔진은 Bongo-town 탑재용으로 기존 1.3l TC 엔진을 volume-up 하여 전 회전 영역에서 괄목할 성능향상을 보였으며 특히 탑재차량의 특성을 고려하여 저속영역 torque를 강조하였고 부품호환성 및 생산 설비의 공용화에도 주력했다. 주요 개발내용은, 1) Cooling passage 개선 및 full siamese화 2) Piston과 connecting rod의 신설계 3) Piston 조합의 semi floating화 4) Cam shaft profile 선정 및 valve timing 변경 5) Distributor 최적진각특성 결정 6) Carburetor 개발 7) Torque limited fan and fan drive 채용 등이다. 상기내용중 중요한 몇가지를 기술하고자 한다.