Effect of bearing preload on the efficiency of automotive manual transmission under RDE driving cycle

The requirements for reduced emissions are forcing automotive manufacturers to design more energy efficient powertrains. Research investigations are focusing on identifying the frictional losses of influencing components, such as gears and bearings. Nevertheless, studying the efficiency of transmissions from a system perspective is a challenging task. In this paper, a dynamic model of a manual transmission system has been developed, including the interactions between its main components. The effect of temperature variation on bearing preload and performance of bearings and gears is considered. The model produces efficiency results for snapshots of the RDE driving cycle, a standard metric of vehicle’s performance.