Advanced Military Diesel Engine, High Temperature Tribology Phase II

"In future advanced military diesel engine propulsion systems, the engine's tribological considerations have been limited by the temperature capability of the lubricating fluid. Thermal oxidation resulting in lubricant breakdown and formation of films anddeposits are typical causes of engine failure in the high operating conditions projected for Low Heat Rejection (LHR) type diesel engines. Work in the Phase I program to this proposed effort expounds upon or previous work to develop both solid lubricantcoating and high temperature lubricating fluids. The objective was to eliminate either the need for high temperature oils, or develop a higher operating temperature fluid. Goals for combined material wear rate has been achieved through the use of IronTitanate (Fe2TiO5) cylinder liner coating and sealed plasma sprayed molybdenum coatings operating at 1000F using experimental basestock oils. The friction coefficient goal of f  0.10 was also met, yet not sustainable for longperiods of time. This only was possible through the replacement of the sealed molybdenum plasma spray with a Diamond Like Carbon (DLC) film. The DLC used in previous tests was soft and would wear away rapidly. Phase I work sought to examine other DLCfilms in existence and further develop basestock lubricating fluids with minimal additives. This type of lubricating fluid would have high thermal stability and lower deposit formation tenden