Effect of liner surface properties on wear and friction in a non-firing engine simulator

Abstract

The performance of a combustion engine is closely related to the friction force and wear between cylinder liner and piston rings. It is believed that this friction force can be significantly reduced by optimizing the surface topography of cylinder liners. Therefore, it is necessary to understand how liner surface topography affects wear, friction and lubricating oil consumption. Several experimental studies have been carried out for evaluating wear and friction in simulated engine conditions using Cameron–Plint wear testers, Pin-on-disk testers, SRV testers, etc. However, these studies do not reflect the true behaviour of inside the engine because of stroke length limitations. In this paper, a non-firing engine simulator has been developed in order to simulate engine conditions to a closer extent compared to these machines. This simulator can operate at similar linear speed, stroke, and load as real engine and can simulate almost all engine operating conditions, except firing pressures. In the present study, a production grade cylinder liner has been used for the experiments conducted using a custom-made non-firing engine simulator. The wear and surface property behaviour were evaluated at several locations in the liner and found that after running-in an engine, surface of cylinder liner exhibits plateau-honed-like characteristic. Energy dispersive analysis (EDS) has been carried out of liner and top ring for evaluating materials transfer. Coefficient of friction between three different liner segments and ring was evaluated using an SRV wear tester. Coefficient of friction in the piston ring–liner interface increases with increasing average surface roughness for liner.