CAUSES OF DESTRUCTION DURING OIL STARVING IN THE FRICTION COUPLE "PISTON RING - CYLINDER LINER"

Abstract

The study deals with the phenomenon of wear in the friction pair of the piston ring -cylinder liner during bench tests on prototypes. The tribological performance of dry frictionsimulating oil starvation was evaluated using the reciprocating motion of the tribometer. Significantwear was observed on the surface of the sleeve, made of gray cast iron, in contact with the chromesteel surface. This can be explained by a significant gradient in the rigidity of the tribopair inconjugation. With a chrome coating that has a noticeable hardness, extrusion and foaming of thesurface are observed along the edge of the sleeve, which indicates a change in wear. The coefficientof friction in dry sliding with stepped load increases showed an unstable state of friction, which isnot appreciated in the operation of any tribological system.Piston rings are used to seal the exhaust outlet gap between the piston and the liner for efficientoperation of the internal combustion engine. The distribution surface of the cylinder liner and pistonring during reciprocating motion is subject to continuous wear due to constant stresses, hightemperatures and intense loads. Thus, the performance and reliability of such heavy-duty enginecomponents depend on the topography of the conjugate surfaces and the associated tribologicalinteractions. Therefore, it is necessary to study the tribological behavior of conjugates of liners -rings that are subject to wear during oil starvation, and designed to effectively prevent exfoliation.This phenomenon leads to new surface coatings and modifications with significant wear propertiesin difficult operating conditions. Under certain conditions of loading, sliding and lubrication, the temperature rises to a criticalstate, the formation of the lubricating film is stopped and any formed lubricating film is destroyed,which leads to a catastrophic increase in friction. This continuous thermal feedback with the contactzone leads to wear of the friction pair of the piston ring - the cylinder liner. Given the changes in thedesign and materials of the engine, despite the fact that engine performance has increasedsignificantly with reduced emissions, it is impossible to exclude increased performance and enginefailure.