Piston Ring Lubrication and Cylinder Bore Wear Analysis, Part I—Theory

Abstract

An analytical method developed for determining the bore wear pattern for a reciprocating piston engine over a complete running cycle is presented. The method includes the considerations of the hydrodynamic lubrication theory between the ring and the cylinder bore wall, piston ring geometric and elastic characteristics, blowby through the piston ring pack, minimum film thickness permitting film lubrication, piston side thrust load and Archard’s wear relation. Since the method is general, it also can be applied to other reciprocating piston devices, such as gas compressor, Rankine cycle engine or Stirling engine. Wear factor data, however, must be available in order to make quantitative predictions of wear. The verification of the present theory is given in a subsequent paper (Part II) which shows good agreement between the predicted bore wear curves and measured ones for actual engines.