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The performance of the Common Rail diesel injection system (CRS) is investigated experimentally in a single cylinder engine and a test rig to determine the cycle-to-cycle variation in the injection pressure and its effects on the needle opening and rate of fuel delivery. The engine used is a single cylinder, simulated-turbocharged diesel engine. Data for the different injection and performance parameters are collected under steady state conditions for 35 consecutive cycles. Furthermore, a mathematical model has been developed to calculate the instantaneous fuel delivery rate at various injection pressures. The experimental results supported with the model computations indicated the presence of cycle-to-cycle variations in the fuel injection pressure and needle lift. The variations in the peak-cylinder gas pressure, rate of heat release, cylinder gas temperature and IMEP are correlated with the variation in the injection rate.

Lubrication of advanced high temperature engines has been one of the greatest obstacles in the development of the Adiabatic engine. Liquid lubricants which gave lubricating properties as well as heat removal function can no longer carry out this duty when piston ring top ring reversal temperatures approach 540°C. Solid lubricants offer some hope. Since solid lubricants cannot perform the heat removal function, its coefficient of friction must be very low, at least <0.10, in order to prevent heat build up and subsequent destruction to the piston rings and cylinder liners. The Hybrid Piston concept developed in the U.S. Army Advanced Tribology program offers some hope, since the top solid lubricant ring slides over the bottom hydrodynamic lubricant film section during each stroke. This paper presents the progress made with the solid lubricant top ring in the Hybrid Piston. Four materials have shown promise in the laboratory to fullfil its mission.

New high-temperature lubricants are being developed for future U.S. Army low heat rejection diesel engines. Compared to the best previous low heat rejection diesel engine lubricant, the first new lubricant developed was shown to (1) be less volatile, (2) have 55°C (100°F) greater oxidative stability, and (3) increase high-temperature single cylinder engine life more than five times. The new lubricant successfully completed a 400 hr multicylinder engine test in a U.S. Army 5-ton truck adiabatic engine. Lubricant property changes, engine wear, deposits and oil consumption were all very low. Two additional new liquid lubricants were developed for operation at higher engine temperatures than those of the 5-ton truck. Engine tests of these new lubricants will be conducted in the near future. Hybrid liquid/solid lubricants were formulated and evaluated for potential reduction of wear and friction at high temperature, with mixed results.