• Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
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• 1996.05a
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• pp.30-35
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• 1996

An elastohydrodynamic lubrication (EHL) analysis for an axially crown profiled cylindrical roller is carried out using a finite difference method and the Newton-Raphson method. Variations of the minimum film thickness with dimensionless parameters show considerably different from those of infinite solutions.

• Tribology and Lubricants
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• v.26 no.4
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• pp.240-245
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• 2010

This paper describes the influence on engine main bearing behavior of the oil film when the fuel is diluted on a diesel engine equipped with DPF system. Oil film pressure and the thickness is calculated in accordance to the fuel dilution. The calculation is based on the numerical analysis of the engine main bearing. As a result, the engine oil viscosity decreased as the fuel dilution increased. This led the increment of the maximum oil thickness pressure. Verification of the minimum oil film thickness settlement by the engine gas pressure and the fuel dilution was confirmed. Destruction possibility of the engine main bearing was foreseen when the engine speed was 2000 rpm with the fuel dilution 15% and the 5W40 engine oil.

• Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
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• 2004.11a
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• pp.275-282
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• 2004

The engine bearing transmits the powers from cylinder to crankshaft with small clearance between con-rod and crankpin. The minimum oil film thickness is a significant parameter in the operation of bearing. The contact pressure of bearing should be considered for the reason that elastic deformation of bearing be caused by contact pressure of bearing. There are important factors which are maintaining of minimum oil film thickness expecting of the length of maximum and minimum oil film thickness with changing of the loads to keep running normally. Furthermore, this study is very crucial to develop the design of engine bearing and crankshaft system.

• Journal of Advanced Marine Engineering and Technology
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• v.22 no.1
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• pp.85-91
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• 1998

In this paper, an influence of inlet pressure on the running characteristics of tilting pad thrust bearing is studied by a numerical analysis. The inlet pressure is obtained from the extended Bernoulli equation including the loss coefficient which is varied with the operating conditions. The running characteristic parameters such as the minimum film thickness, the film pressure and the film thickness ratios are calculated for various runner speeds with constant load in particular two pivot positions. The results are shown that the inlet pressure has a large influence on the minimum film thickness and other running characteristic parameters.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1997.04a
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• pp.578-583
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• 1997

Abstract-Crosshead bearing in two-stroke marine diesel engine is operated under quite severe condition since the load on the bearing is sybject to the loading in a unidirectional and the sliding speed is very slow and oscillatory. So it is very difficult to form oil film and maintain the load. In this paper, two types of bearing are compared. One has large sized oil pocket and the seleted as multi-small oil grooves. Bearing clearance, oil inlet oressure and bearing types are selected as analysis parameters. Loci of journal center are presented to compare several cases. It is found that bearing clearance and shape affect to minimum film thickness.

• Journal of Drive and Control
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• v.10 no.3
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• pp.7-13
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• 2013

Hydraulic vane pumps are widely used in various hydraulic systems because of its compactness and light weight. It is well known that the vanes and cam ring are separated by very thin liquid films which result in the EHL state. Contrary to the case of cylindrical roller bearings, the inlet and side boundary pressures are much higher than the atmospheric pressure. In this paper, a numerical solution of the EHL of finite line contacts between the cam ring and vane tip with profiled ends is presented. Using a finite difference method with non-uniform grids and the Newton-Raphson method, converged solutions are obtained for moderate load and material parameters. The EHL pressure distribution and film shape are considerably affected by pump delivery pressure and the side boundary condition applied. Both the maximum pressure and the minimum film thickness always occurred near the edge regions. The present results can be used in the design of optimum vane profile in hydraulic vane pump.

• Transactions of the Korean Society of Automotive Engineers
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• v.12 no.4
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• pp.36-41
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• 2004

The purpose of this paper is analyzing the oil film pressure distribution and the minimum oil film thickness for a connecting rod bearing using an A VL's EXCITE program. It is very important to understand optimized oil supplying holes and oil groove dimensions for supporting sufficiently inertia forces and gas pressures from the combustion chamber for a Diesel engine. The computed results indicate that the optimized oil groove width of a bearing and oil hole of a journal are recommended for high performance of a connecting rod bearing at the elastohydrodynamic lubrication zone. These results as design parameters are very useful data for a bearing designer as a firm reference of an automotive engine.

• Tribology and Lubricants
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• v.25 no.3
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• pp.157-162
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• 2009

In this paper, the hydrodynamic pressure and minimum oil film thickness of a pin bush bearing for a connecting rod have been analyzed as functions of the number of oil grooves and an arc length of oil grooves. The lubrication characteristic of a pin bush is governed by oil groove design factors, which are considered in this study. The most influential design parameter is a number of oil grooves, which is three oil grooves with an arc length of oil groove, 1/6($60^{\circ}$). This means that oil groove with a long arc length of a pin bush does not contribute to the hydrodynamic pressure development. Thus the optimal design of a pin bush is necessary with an increased number of oil grooves and a reduced arc length.

• Transactions of the Korean Society of Automotive Engineers
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• v.12 no.4
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• pp.34-34
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• 2004

The purpose of this paper is analyzing the oil film pressure distribution and the minimum oil film thickness for a connecting rod bearing using an A VL′s EXCITE program. It is very important to understand optimized oil supplying holes and oil groove dimensions for supporting sufficiently inertia forces and gas pressures from the combustion chamber for a Diesel engine. The computed results indicate that the optimized oil groove width of a bearing and oil hole of a journal are recommended for high performance of a connecting rod bearing at the elastohydrodynamic lubrication zone. These results as design parameters are very useful data for a bearing designer as a firm reference of an automotive engine.

• Tribology and Lubricants
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• v.31 no.6
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• pp.245-250
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• 2015

This study investigates the lubrication characteristics of fuel injection pumps with reference to different fuel oils. Medium-speed diesel engines use fuel oils with various viscosities, such as heavy fuel oil (HFO, which is a high-viscosity fuel oil) and light diesel oil (LDO, which is a low-viscosity fuel oil). When fuel oil with a low viscosity is used, both fuel oil and lubricating oil lubricate the system. Thus, the lubrication of the fuel injection pump is in a multi-viscosity condition when the fuel oil in use changes. We suggest three cases of multi-viscosity models, and divide the fuel injection pump into three lubrication sections: a, the new oil section; b, the mixed oil section; and c, the used oil section. This study compares the lubrication characteristics with variation of the multi-viscosity model, clearance. The volume of Section b does not affect the lubrication characteristics. The lubrication characteristics of the fuel injection pump are poor when high-viscosity fuel oil transfers to low-viscosity fuel oil. This occurs because the viscosity in the new oil section (i.e., Section a) dominates the lubrication characteristics of the fuel injection pump. However, the lubricant oil supply in the used oil section (i.e., Section c) can improve the lubrication characteristics in this condition. Moreover, the clearances of the stem and head significantly influence the lubrication characteristics when the fuel oil changes.