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.

Effect of Initial Cylinder Liner Honing Surface Roughness on Aircraft Piston Engine Performances

“…On the other hand, such a microstructure of the plateau profile results in an increased lube oil consumption and exhaust emission of soot and particles (particulate matter), carbon oxides [carbon monoxide (CO), carbon dioxide (CO 2 )], and hydrocarbons (HC) [6,12]. The oil film thickness, pressure, and oil blow-by volume depend directly on the width and depth of honing scratches, and the distance between them [13]. Some models of friction and oil flow through the liner surface roughness are discussed by Jocsak et al [14], including the gasoline and diesel engine performance parameters as a function of cylinder liner roughness heights, the distribution of their coordinates, honing crosshatch angle, and lubrication oil properties.…”

Determination of fundamental parameters for the cross-hatched cylinder liner micro-geometry

“…Mezghani et al 15 propose hydrodynamic friction calculations under point contact EHL conditions of real cross-hatched surfaces and show no significant influence of the groove depth. A complementary but possibly important aspect concerns the oil redistribution; this aspect is studied using analytical cross-hatched surfaces by Organisciak et al 16 The current work tries to extract groove geometry information and to separate the grooves from the plateau. Since the main grooves are identified, the rest of the surface micro-geometry (not identified small grooves and 'random' roughness) can be accounted for by statistical parameters using the Greenwood and Tripp theory.…”

Finite element method for starved hydrodynamic lubrication with film separation and free surface effects

“…But this kind of flow is unrealistic in the case of film separation, which is more common in non-conformal hydrodynamic contacts like e.g. piston ring lubrication, although it has been applied in a few instances as in (Organisciak et al, 2007) and (Zhang et al, 2016), in the lack of a better approximation. Aim of the present work is to fill this gap, providing a numerical model which combines free surface flow in partially flooded regions with the classical Reynolds equation in the pressurized zone.…”