The Effects of Roughness on Piston Ring Lubrication—Part II: The Relationship between Cylinder Wall Surface Topography and Oil Film Thickness

Based on the two-dimensional average flow model and asperity contact model, a theoretical model for the non-axisymmetrical analysis of piston ring lubrication has been suggested in this paper. The two-dimensional distribution of oil-film thickness between the piston rings and cylinder wall is obtained. Results show that the oil-film thickness along the circumference is non-uniform. Starvation is also considered in the model. The effect of secondary motion of piston assemblies on the lubrication property of the piston ring pack has also been studied.

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Analysis of Tribological Performance of Piston Ring Lubrication

ASME 2011 Internal Combustion Engine Division Fall Technical Conference ◽

10.1115/icef2011-60036 ◽

2011 ◽

Author(s):

Yibin Guo ◽

Wanyou Li ◽

Dequan Zou ◽

Xiqun Lu ◽

Tao He

Keyword(s):

Film Thickness ◽

Friction Force ◽

Power Loss ◽

Piston Ring ◽

Design Parameters ◽

Oil Film ◽

Starved Lubrication ◽

Piston Ring Lubrication ◽

Cylinder Bore ◽

Lubrication Conditions

In this paper a mixed lubrication model considering lubricant supply conditions on cylinder bore has been developed for the piston ring lubrication. The numerical procedures of both fully flooded and starved lubrication were included in the model. The lubrication equations and boundary conditions at the end of strokes were discussed in detail. The effects of piston ring design parameters, such as ring face profile and ring tension, on oil film thickness, friction force and power loss under fully flooded and starved lubrication conditions due to available lubricant supply on cylinder bore were studied. The simulation results show that the oil available in the inlet region of the oil film is important to the piston ring friction power loss. With different ring face crown heights and tensions, the changes of oil film thickness and friction force were apparent under fully flooded lubrication, but almost no changes were found under starved lubrication except at the end of a stroke. In addition, the oil film thickness and friction force were affected evidently by the ring face profile offsets under both fully flooded and starved lubrication conditions, and the offset towards the combustion chamber made a large contribution to forming thicker oil film during the expansion stroke. So under different lubricant supply conditions on the cylinder bore, the ring profile and tension need to be adjusted to reduce the friction and power loss. Moreover, the effects of lubricant viscosity, surface composite roughness, and engine operating speed on friction force and power loss were also discussed.

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The Effect of Oil Evaporation From the Cylinder Wall on Oil Consumption of a Gasoline Engine

ASME 2009 Internal Combustion Engine Division Fall Technical Conference ◽

10.1115/icef2009-14051 ◽

2009 ◽

Cited By ~ 2

Author(s):

Yasuo Harigaya ◽

Kazuyoshi Yamasuga ◽

Michiyoshi Suzuki ◽

Naoki Iijima ◽

Masaaki Takiguchi ◽

...

Keyword(s):

Film Thickness ◽

Gasoline Engine ◽

Hydrodynamic Lubrication ◽

Film Surface ◽

Cylinder Wall ◽

Oil Consumption ◽

Oil Film ◽

Evaporation Model ◽

Low Load ◽

The Relationship

A new oil evaporation model was developed, combining a thermo-hydrodynamic lubrication model with a conventional oil evaporation model considering the energy balance on the oil film surface. This model assumed that there was evaporation loss of the oil film on the cylinder wall. In addition, the effects of the oil film thickness and types of lubricant in the evaporated oil from the liner were examined. Moreover, the calculated evaporative oil was compared with the measured oil consumption of a gasoline engine. The relationship between the evaporated oil, the lubricant viscosity, and the oil film thickness were clarified using this model. The results showed that the calculated oil evaporation from the cylinder wall closely corresponded to the measured oil consumption under low load conditions.

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The compression ring profile influence on hydrodynamic performance of the lubricant in diesel engine

Advances in Mechanical Engineering ◽

10.1177/1687814020930845 ◽

2020 ◽

Vol 12 (6) ◽

pp. 168781402093084

Author(s):

Brahim Menacer ◽

Mostefa Bouchetara

Keyword(s):

Diesel Engine ◽

Film Thickness ◽

Piston Ring ◽

Hydrodynamic Lubrication ◽

Operating Conditions ◽

Hydrodynamic Performance ◽

Cylinder Wall ◽

Power Losses ◽

Oil Film ◽

Compression Ring

For different operating conditions of an internal combustion engine, the piston–ring–liner compartment represents one of the largest sources of friction and power losses. The aim of this article is to evaluate the effect of the compression ring profile on the main tribological performance of the lubricant in a four-stroke diesel engine. A one-dimensional analysis was developed for the hydrodynamic lubrication between the compression piston ring and the cylinder wall. A numerical method was applied to analyze the influence of different ring geometrical designs during the working cycle on oil film thickness, frictional force, and power losses. Our predicted results were validated with the Takiguchi data of a previous study, and they have shown a good agreement. The results in the current analysis demonstrated that the ring geometry profile, the engine speed, and load have a remarkable effect on oil film thickness, friction force, and friction power losses between the top ring and cylinder liner. Therefore, it would help in reducing friction as well as making a contribution to the improvement of engine performance such as torque, efficiency, and fuel consumption.

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