12. Tribological Studies of an Internal Combustion Engine

Industrial lubricants are invariably used with organo-metallic additives [such as complex sulphates and phosphates Zinc dialkyldithiophosphate (ZDDP)] for tribological performance enhancement of machines such as internal combustion (IC) engines. However, these additives are environmentally harmful and they also have damaging effects on the steel components of the engine. Hence, there is an urgent need to find alternative solutions for enhancing the tribological performance of lubricants and components without the application of such harmful additives. Epoxy-based composites are promising tribological coatings, which can provide low friction and high wear life under dry, as well as base-oil lubricated conditions. The present chapter focuses on reviewing the mechanisms of achieving improved mechanical properties with a low coefficient of friction (CoF) in typical demanding applications, such as IC engines. The applications of epoxy composite coatings can be in extreme contact conditions such as engine piston rings and bearings. The best suitable coatings, namely epoxy/graphene/SN150 with DLC and WC as the intermediate hard coatings, were applied on the piston rings of a diesel engine and experiments were performed in order to permit wear analysis of coated rings.