Coupled evolution process of lubrication and wear in piston-liner interface of high-pressure common rail pumps

Abstract

As a pivotal frictional pair of piston pumps, the piston-liner interface is vulnerable to rapid wear in the face of severe environment, triggering a consequent contraction in the piston pump's service longevity. Based on statistical theory, a transient mixed lubrication model has been established in this work, which takes the surface roughness effect, thermal-elastic deformation, as well as the piston micro-movements into account. In conjunction with the wear calculation model, we propose a novel lubrication-wear coupling strategy for the piston-liner interface, enabling a nuanced exploration of the transient interdependency link between lubrication efficiency and wear characteristics. To underscore the robustness of our proposed model, a comparison is drawn with experimental results gleaned from established literature. This investigation not only provides insights into the progression of wear depth and lubrication efficiency throughout a given time frame. but also assesses the impact of varying operational parameters on wear depth Parametric studies reveal that the wear region predominantly occurs at the inlet and outlet positions of the liner. Furthermore, both working pressure and cam rotational speed significantly influence the interface's lubrication characteristics and wear behavior. Consequently, in piston systems operating under high-pressure and high-speed conditions, it is imperative to closely monitor wear patterns and consider the impact of thermal effects.