Yip-Wah Chung Subproject for Institution # SP0024150

The proposed research aims at developing a novel lubricant formulation scheme for improving the fuel efficiency of light and medium vehicles by at least 2%. We plan to achieve these objectives by reducing friction due to (1) asperity rubbing in starting and low-speed operations during which boundary friction controls energy dissipation and in oil aeration where lubrication breaks down, and (ii) high viscous shear rate at high-speed cruise operations during which viscous loss is the dominant mechanism for energy dissipation. Reducing friction in these two regimes, especially in the former, not only improves fuel efficiency, but also durability of the powertrain. We will achieve these objectives by first incorporating novel cyclophosphazine additives to reduce boundary friction. Cyclophosphazine molecules can bind strongly to metal surfaces to provide sufficient asperity separation at contact stress and ineffective fluid lubrication. We will develop a novel scheme for designing and examining viscosity modifiers with a desired temporary shear-thinning characteristic while maintaining other properties, i.e., the lubricant viscosity decreases with increasing shear rates, thus reducing viscous energy loss in the hydrodynamic regime. Design and syntheses of new additives and analyses and testing of the new lubricants will be conducted. Our major research effort will be focused on engine oils; however, we expect that this novel scheme can be readily extended to the design of transmission fluids as well. The proposed products root in existing technologies, thus immediate implementation is expected once they are successfully developed.