TRIBOLOGICAL EVALUATION OF PISTON SKIRT/CYLINDER LINER CONTACT INTERFACES UNDER BOUNDARY LUBRICATION CONDITIONS

摘要

The tribological behavior of skirt specimens that were either uncoated or coated with a graphite/resin coating sliding against cylinder liners was examined. The quick formation of a low friction tribochemical film was evident at temperatures of 120℃ due to the activation of additives in the oil at high temperatures. At lower temperatures viscosity effects were dominant while at 70℃ a friction reduction was achieved due the slow formation of a tribochemical film.rnFinally, use of a graphite/resin coating in piston skirt specimens tested in three different oils did not offer any improvement while it was detrimental for one of the oils as the coating debris may have interacted with the additives or may have prevented the formation of a tribochemical film due to wear. However, the possibility of using a graphite/resin coating when testing with different oils than the oils tested in this work should be considered as in different oil formulations such coating may not have a negative role.