Variable lubricant supply of a starved hydrodynamic linear contact: Lubricant lateral flow for smooth and laser textured surfaces

Abstract

This article presents the study of a starved hydrodynamic linear contact with a variable lubricant inlet layer. Variable lubricant films are likely to occur in piston rings-cylinder liner contacts. The lubricant layer is assumed to have a sinusoidal shape with a defined wavelength in the direction perpendicular to the direction of movement. The contact is modelled in pure rolling. Two equally large zones can be defined: a severely starved central zone, around the minimum of the sine function, and a lightly starved zone, around the maxima of the sine function. This kind of inlet lubricant distribution affects the pressure and the lubricant distribution: after a passage, a part of the lubricant present in the lightly starved zone is transferred to the severely starved zone. An efficiency parameter ER of the lubricant reflow is defined. First, the results show the evolution of the lubricant reflow as a function of the operating conditions, i.e. speed, load and lubricant film thickness, and the wavelength of the lubricant distribution. Second, the number of passages necessary to reach complete lubricant redistribution is determined. Finally, a textured surface with a cross-hatched pattern is introduced. Such a surface reduces the number of passages necessary to reach the complete redistribution. The choice of an optimized surface pattern can reduce the risk of local contact failure because of local lack of lubricant.