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 rigidcondition breakdown and formation of deposits are typical causes of engine failure at high temperature operating conditions. Work in the Phase I program seeks to review all sliding wear tribological aspects of an FCS type military diesel engine. Asystematic 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 phenomenoncan 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 410¿TRR and 175¿C 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 toselect specific basestock oil formulations and additive components. We will use a laboratory bench test apparatus that will generate eight lubricant performance parameters in real time to assess synthesized lubricants and select the best lubricantcomponents and synthesize a lubricant for small bore single cylinder LHR diesel engine lubricant screening tests. For the interim Phase I Option work, the best lubricant will be optimally formulated for a full scale LHR engine test that will subject thelubricant 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. Benefitsof a successful research & development effort are immediate. They will provide a tremendous impact contribution to high temperature diesel engine operation in terms of engine performance, reliability and durability, because a 410¿C TRR, 175¿C sumptemperature capable diesel engine compatible lubricant currently does not exist. The use of mathematical model or modeling equations to generate required tribology parameters will generate a method to determine tribology solutions for other powerplantsand applications. Potential commercial applications would be more in using this method to generate tribology solutions for automotive and industry applications because the modeling equations would be the same.