Development of the minimum-friction adiabatic engine

The Minimum-Friction Adiabatic Engine Program was initiated by Cummins Engine Company and the U.S. Army Tank-Automotive Command to research the feasibility of a significant reduction in an engine's mechanical friction. Basically, three areas are unique to this engine: gas-supported piston assembly; solidlubricated ceramic ball and roller bearings for the crankshaft, crankpin, wrist pin, and turbocharger; and solid-lubricated timing gears, camshaft, and valveand injector-train bearings. Oil lubrication and water cooling of the entire engine, including the turbocharger, are eliminated. Based on computer calculations, a reduction in the engine mechanical friction of approximately 75% is estimated. Rig tests of each component have been completed and a single-cylinder engine has been successfully operated for a limited time.