Investigating the efficiency of automotive manual gearboxes by experiment and simulation

Energy losses in the drivetrain are a steady topic within the automotive industry, be it to lower emissions and fulfill demands by legislation or to stay longer on the track with a single filling of the fuel tank as in motor sport applications. All of these reasons fuel the motivation to reduce these parasitic losses. In this paper, the major sources of the energy losses in a gearbox are discussed. After the discussion of the sources, the losses in a longitudinally installed manual gearbox are investigated by using both experimental measurements as well as simulation. For the simulation, convenient empirical formulas from literature are used to describe the individual loss processes and combined together to describe the friction power losses of the entire gearbox. The comparison between simulation and the extensive experimental data show good agreement.