Influence of piston ring profiles and oil temperature distribution on cylinder liner lubrication of a marine two-stroke engine

Abstract

In the paper a comprehensive model of a piston-ring-cylinder (PRC) system has been presented. The local thickness of the oil film can be compared to height of the combined surface roughness of a cylinder liner and piston rings. Equations describing the mixed lubri-cation problem based on the empirical mathematical model formulated in works of Patir, Cheng and Greenwood, Tripp have been ap-plied. The main parts of the model have been experimentally verified abroad by the author at the marine engine designing centre. In contrast to the previous papers of the author concerning the PRC system of combustion engines, new calculation results for a ma-rine two-stroke engine have been presented. Firstly the right selection of barrel-shaped sliding surface of piston rings has been analysed. Secondly the influence of oil temperature distribution along the cylinder liner on the lubrication of the PRC system has been assessed. The developed model and software can be useful for optimization of the PRC system design.

Keywords

• marine engines
• piston rings
• gasdynamics
• hydrodynamic lubrication
• mixed friction