Lubricant surface system for high performance transmissions

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System level adaptations to automotive transmission systems have improved overall efficiency at the cost of increasing the parasitic frictional losses at the tribological conjunction between meshing gear teeth. Frictional losses detract from the efficiency of automotive transmission systems and the vehicles in which they operate. Due to the severity of the contact between the gear teeth the role of lubricant additives and advanced surface coatings has become critical. The focus of the current work is determining how advanced surface coatings, surface finishing procedures and lubricant interactions can be harnessed to improve energy efficiency of automotive transmissions. This work will be completed by conducting a novel experimental approach which investigates the surface topography and frictional behaviour across multiple length scales. The measurements will be conducted using atomic force microscopy, lateral force microscopy, optical interferometry, tribometry and x-ray photoelectron spectroscopy. The experimental work will be complemented by the use of analytical models that will help elucidate the physical phenomena observed during the experimentation. This novel approach allows for identification of advantageous lubricant surface combinations and the physical mechanisms which determine the combination to have low frictional losses. The development in fundamental understanding generated by this research will enable improved selection of surfaces and lubricants for high shear, high temperature and high pressure tribological conjunctions by understanding their dependency.