Smoothness and plateaudness contributions to the running-in friction and wear of stratified helical slide and plateau honed cylinder liners

Abstract

Cylinder liner surface has a great influence on frictional and wear performances of combustion engines during the running-in period. Two surface texture anisotropies produced by plateau honing (PH) and helical slide honing (HSH) processes (which consist of 50° and 130° cross-hatched grooves, respectively) are commonly used in automotive industry for thermal combustion engine cylinder liners. They are generated by a three stages process. The first stage, rough honing, removes enough material to obtain the desired cylindricity. The second step, finish honing, generates the honed texture which consists of grooves with a specific cross-hatch angle. The third stage permits to reduce the surface peaks and therefore allows varying plateau superficial roughness amplitude. This paper is devoted to studying the influence of respectively smoothness and plateaudness on honed surface wear and friction performances during running-in. For that, HSH and PH textures are generated using different final honing stage durations in order to obtain different levels of surface peak clipping. Then, friction, wear and surface topography evolution were analyzed during running-in tests on a reciprocating ring-liner tribometer under mixed lubrication regime. The results show that the superficial surface roughness generated by helical slide honing has a very low contribution into friction. This is promising for the honing process optimization, in which the third stage can be significantly reduced or avoided.