Study On Tribological Properties Of Surface Texturing Piston Rings

The property of cylinder liner and piston ring mating, which is the most critical friction pair, determines the internal combustion engine's efficiency and service life. In order to improve it, people make use of surface texturing technology by processing a series of regular arrays of pits to reduce the friction and wear loss of cylinder liner-piston ring friction pair.The application of surface texturing technique in piston liner and ring pair was studied theoretically in this thesis. The lubrication model of a column of micro texturing pits was established considering the dynamic pressure effect and the squeeze effect, without considering the uneven loading distribution, asperity and deformation of contacting area. The influence of surface texture parameters on piston ring lubrication performance was obtained by solving the mathematical model with multi-grid method. The minimum oil film thickness and dimensionless friction between piston ring and cylinder liner were taken as a criterion to estimate the lubricating effect and analyze various parameters of surface texture, such as:the texture appearance, size and depth. It was shown that the texture appearance has little influence on the lubrication, under the pit area ratio of 5%-40% the minimum oil film thickness increased and the dimensionless friction force reduced with the increasing of it. Under the pit area ratio of 40%-60%, the minimum oil film thickness and the dimensionless friction force have changed slightly. Under various pit area ratios the optimum pit depth is about 5μm and a good hydrodynamic lubrication can be gained.This thesis analyzes the impact of surface texturing on the piston liner and ring lubrication, and provides a theoretical basis for surface texturing's application in piston ring.