Tribological study of piston-cylinder interface of radial piston pump in high-pressure common rail system considering surface topography effect

摘要

Based on the theory of thermal fluid dynamic lubrication, the Reynolds equation and energy equation of the average flow of a piston-cylinder interface of a radial piston pump in a high-pressure common rail system are established, considering the surface topography effect. The tribological properties of the piston-cylinder interface are calculated by solving the Reynolds equation and energy equation. A surface wear model is established and the wear distribution and trend of the piston-cylinder interface are studied. The wear characteristics of the piston-cylinder interface are verified through experiment, and the wear lubrication of the piston-cylinder interface is discussed. The surface topography effect has a considerable influence on the characteristics of the piston-cylinder interface film. Different surface morphologies change the film characteristics of the piston-cylinder interface, yielding different wear behaviors on the mating surface. The wear of the piston-cylinder interface first decreases along the film outlet to the inlet and then rises. The cylinder surface mainly exhibits abrasive, cavitation, and micro-convex scratch wear, whereas the piston surface mainly shows cavitation wear. The results obtained in this study are of considerable significance as they reveal the tribological properties of the piston-cylinder interface under the surface topography effect.