Modeling and analyzing the power losses in vehicle transmissions

The power losses inside vehicle transmissions are related directly to the efficiency of vehicle systems. Hence, it is worth researching the overall power losses of transmissions, in order to develop the measures to reduce the overall energy consumption in vehicle powertrains. It is then necessary to put forward a general method to estimate the power losses in vehicle transmissions. In this work, a general overall power loss model of vehicle transmissions is established, based on component power loss models in the literature. Furthermore, a methodology concerning the analysis of the power losses inside vehicle transmissions is introduced. One part of the methodology is the calculation of component loads and speeds for the overall power loss model. To improve the estimation of the overall power losses, parameter sensitivity analysis and parameter identification strategy are employed in the methodology, with the help of experimental data from test rigs. Besides, cross validation is also introduced to avoid over-fitting. The overall power loss model and the methodology are applied onto three different transmissions. In comparison with a standard model, the results of the overall power loss model have a better agreement with experimental data. Moreover, with the help of the methodology, accurate power loss distributions of these vehicle transmissions are possible to be obtained. It is expected that by means of the overall power loss model and the methodology in this work, a platform can be set up to investigate and benchmark different vehicle transmissions in terms of their efficiency in the future.