Metallurgical and metrological examinations of the cylinder liner-piston ring surfaces after heavy duty diesel engine testing

This paper will discuss results of metallurgical and metrological examinati ons of cylinder liner and piston ring surfaces before and after 150, 1000 a nd 4000 hours of heavy duty diesel engine testing. Three different composit ion coatings and three methods of application were investigated, including electroplating, plasma and HVOF spraying. To examine metallurgical paramete rs such as porosity, microhardness, microstructure and their changes after testing, scanning electron microscopy and energy dispersive X-ray spectrosc opy were used. The cylinder liner and piston ring surface profile and rough ness parameters include Ra, Rz, Rk, Rvk, Rvk, skewness, oil retention volum e, etc. The mechanisms of scuffing origin and final wear were evaluated for different piston ring coatings and methods of application. The paper will show the correlation between metallurgical and metrological parameters and efficiency of the cylinder liner-piston rings tribological system. The data fi om these examinations formulates required performance for transformatio n of abnormal and/or severe type of wear to mild processes.