• 한국자동차공학회논문집
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• 제2권5호
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• pp.1-10
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• 1994

By applying of total electric capacitance method on engine connecting rod bearing during engine operating, the influence of engine operating conditions and lubricants on bearing oil film thickness was investigated. Minimum oil film thickness increases with kinematic viscosity, but as increasing of viscosity, the increasing ratio of film thickness is reduced. Also minimum oil film thickness increases with engine speed but there is a limit. Above this limit, film thickness decreases in opposition because of crankshaft inertia. As increasing of engine torque and oil temperature, munimum oil film thickness decreases linearly. For non-Newtonian oils, the correlation between $100{\circ}C$ kinematic viscosity and munimum oil film thickness is very poor.

• Tribology and Lubricants
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• 제25권5호
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• pp.318-323
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• 2009

The oil characteristics and wear particles of Diesel engines with a DPF have been investigated as a function of a driving distance. The engine oil of SAE 5W30 with ACEA C3 is used for an oil film lubrication of the engine, which is equipped with Diesel particulate filter. Depending on the oil test results, the kinematic viscosity of used engine oils at 40 is degraded up to 5.1% compared with that of unused engine oils, SAE 5W30. And the kinematic viscosity of used engine oils at 100 is more degraded up to 8.1% compared with that of unused engine oils. The oil characteristic as a function of a mileage is not changed depending on the driving distance because of high quality of engine oils. But the aluminum and copper compounds, which are used as base materials of the engine bearing and a pin bush, are much worn and contaminated for the increased mileage of the car. The oil properties of used engine oils are relatively good except phosphorus and calcium additives, which are heavily engaged in the performance of the oils.

• Structural Engineering and Mechanics
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• 제90권1호
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• pp.97-106
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• 2024

This paper presents a significant contribution to aided design by conducting an analytical examination of geometric links with the aim of establishing criteria for assessing an analogy measure of the extrinsic geometric and kinematic characteristics of the Variable Compression Ratio (VCR) engine with a Geared Mechanism (GBCM) in comparison to the existing Fixed Compression Ratio (FCR) engine with a Standard-Reciprocating Crankshaft configuration. Employing a mechanical approach grounded in projective computational methods, a parametric study has been conducted to analyze the kinematic behavior and geometric transformations of the moving links. The findings indicate that in order to ensure equivalent extrinsic behavior and maintain consistent input-output performance between both engine types, precise adjustments of intrinsic geometric parameters are necessary. Specifically, for a VCR configuration compared to an FCR configuration, regardless of compression ratio and gearwheel radius, for the same crankshaft ratios and stroke lengths, it is imperative to halve lengths of connecting rods, and crank radius. These insights underscore the importance of meticulous parameter adjustment in achieving comparable performance across different engine configurations, offering valuable implications for design optimization.

• Tribology and Lubricants
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• 제21권4호
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• pp.159-164
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• 2005

An experimental study was conducted to evaluate characteristic variation of diluted engine oils in which contains diesel fuels and its tribological effects on engine components. In this study, diluted engine oils with $10\%,\;15\%,\;and\;20\%$ of initial fuel content rate have been used for measuring the viscosity reduction rate, blow-by gas increment rate, main gallery pressure reduction rate, and fuel content rate in engine oils. These parameters are strongly related to the tribological characteristics of key engine components. The kinematic viscosity of engine oils in which is contained by diesel fuels from $10\%\;to\;20\%$ in oils is decreasing to approximately $54\%$ of initial diluted fuel-oil volume ratios. The experimental results show that the distillated engine oil decrease the viscosity of engine oil and its oil film stiffness, and increase the wear rate of rubbing parts of engine components. Thus we recommend that the containing volume rate of fuels in engine oils should be restricted to $3\~4\%$ for a sophisticated Diesel engine and $5\~7\%$ for a standard one.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2001년도 춘계학술대회논문집A
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• pp.901-906
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• 2001

Finite element method is used for the structural analysis of low speed large diesel engine structures, and the kinematic and mechanism analysis is performed to compute loads applied to the engine structures. A typical diesel engine is used as an example and static and dynamic structural analyses are demonstrated. Dynamic stress of engine is measured during the sea-trial operation of the ship.

• 한국농공학회지
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• 제16권4호
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• pp.3617-3621
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• 1974

• 한국자동차공학회논문집
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• 제2권4호
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• pp.9-17
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• 1994

Effect of Newtonian and non-Newtonian oils on minimum ol film thickness in engine journal bearing were investigated at various oil viscosities. The influence of oil viscosity and engine operating conditions on minimum oil film thickness of main bearing and con-rod bearing was examined. Minimum oil film thickness for Newtonian oils increased uniformly with kinematic viscosity. But the correlation between kinematic viscosity and minimum oil film thickness was very poor for non-Newtonian oils. According to the straight-line regression analysis for non-Newtonian oils, high temperature high shear viscosity at 1 $1{\times}10^6Sec^{-1}$, $150^{\circ}C$ increase the coefficient of determination from 0.41 to 0.77. Con-rod bearing showed better correlation between minimum oil film thickness and engine operating conditions than main bearing.

• 한국윤활학회:학술대회논문집
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• 한국윤활학회 1997년도 제26회 추계학술대회
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• pp.152-160
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• 1997

A diesel engine oil which was formulated and a commercial diesel engine oil (API CG4) made from same base oil were tested by car and analyzed of their physical, chemical and mechanical properties. The tested oil to be analyzed were sampled from engine every 1000 km until 8000 km and determined the kinematic viscosity, TAN, TBN, metal content in oil, additive depletion, antiwear property and IR analysis. From the study, both the tested oils were almost same properties for the change of TAN and TBN, but the change of kinematic viscosity of formulated oil was slightly higher than that of commercial oil. But the concentration of metal in the formulated oil, especially iron, were increased much less during test. The iron content of the commercial oil was increase rapidly from 7000 km while the formulated oil was still low. These results were conformed by the antiwear test by 4-ball wear test machine for the samples. Also for the commercial oil, the depletion factor of the Zn-DTP which was added as an antiwear property was not change any more after 7000 km. But the formulated oil was change continuously until 8000 km, which mean that the ability of wear protection of the sliding parts exists for the formulated oil. With the results which were analyzed of the properties of oils by field test, it was found that the commercial oil could be used only within 7000 km, but the formulated oil can use more than 8000 km without severe wear of the sliding parts in the diesel engine.

• 한국자동차공학회논문집
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• 제9권3호
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• pp.51-59
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• 2001

A diesel engine oil formulated in KRICT and a commercial diesel engine oil (API CG-4) were tested by car and their Kinematic Viscosity, TAN, TBN, metal content, additive depletion, anti-wear property and IR analysis were analyzed. From the research, both of the tested oils had almost the same properties f3r the change of TAN and TBN, but the change of Kinematic Viscosity of formulated oil was slightly higher than that of commercial oil. The iron content in the commercial oil increased rapidly from 7000 km while that of the formulated oil was still low. These results were confirmed by the anti-wear test with a 4-ball wear test machine for the each samples. Also, for the commercial oil, the depletion factor of the Zn-DTP which was added as an anti-wear property did not change any more after 7000 km. But, that of the formulated oil changed continuously to 8000 km, which means that the ability to prevent wear of the sliding pairs exists for the formulated oil. From the analysis results of oil properties obtained by field test, it was found that the commercial oil could be used only within 7000 km, but the formulated oil could be used more than 8000 km without severe wear of the sliding parts in the diesel engine.

• 한국농업기계학회:학술대회논문집
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• 한국농업기계학회 1993년도 Proceedings of International Conference for Agricultural Machinery and Process Engineering
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• pp.267-276
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• 1993

A kinetmatic stirling engine with a domed heater was designed, fabricated and test. In designing and fabrication of the engine various problems were confronted and solved. Among various parts of the engine, cooler and main seal needed sophisticated techniques to fabricated in order to prevent leakage of working gas from the parts and to ensure their proper functions in the engine. The engine had a series of experiment at various working gas pressure, heater temperatures and engine speeds to evaluate its performance. Indicated and brake power outputs and indicated and brake thermal efficiencies were determined from the experimental data. The engine resulted a little inferior performance to that of the GPU-3 engine of which performance was well reported . Several recommendations were made to improve the performance of the engine during the evaluation of its performance.