High Temperature Tribological Lubricants for Low Heat Rejection, High Temperature Operation Diesel Engine

The Future Combat System (FCS) military diesel engine propulsion systems tribological considerations are predicted to be compromised primarily by the temperature capability of the lubricating fluid. Thermal oxidation resulting in lubricant work in rigid condition breakdown and formation of deposits are typical causes of engine failure at high temperature operating conditions. Work in the Phase II program seeks to review all sliding wear tribological aspects of an FCS type military diesel engine. A systematic approach to generating a tribology solution for high temperature operation is outlined and proposed for solving this issue. Initially, mathematical modeling equations will be generated to model and predict what adverse tribological phenomenon can be expected at a particular sliding wear interface. Lubricant modeling equations exist and will be used to determine what specific lubricant properties are essential in solving critical tribology issues, such as short and long term thermal stability (especially the goals of 410º TRR and 175ºC sump temperatures), long term viscosity, viscosity at given temperature, lubricant chemical modification temperature, to mention just a few of the complex lubricant chemistry. These equations can be used to select specific basestock oil formulations and additive components. We will use a laboratory Tribology complex test apparatus that will generate eight lubricant performance parameters in real time to assess synthesized lubricants and select the best lubricant components and synthesize a lubricant for small bore single cylinder LHR diesel engine lubricant screening tests. In the end of Phase II work, the best lubricant will be optimally formulated for a full scale LHR 6 cylinder Cummins ISB- 305 engine test that will subject the lubricant to target temperatures and hopefully meet friction coefficient goal of = 0.08 to 0.10 with ring liner wear rate at 0.6 mg/hr. Using this approach, will generate solid results and be repeated for other areas or applications.