Electric Transmission System Efficiency Simulation: Planetary transmission mechanical efficiency prediction through CAE simulation

Abstract

Accurate prediction of the range of battery electric vehicles is a major challenge for the OEMs. In order to do so, the power loss which occurs in the vehicle driveline in the driving cycle should be predicted. The transmission system is one of the major contributors to these losses. The investigation presented in this report uses power loss models for the individual machine elements (i.e.: bearings, gears, seals and thrust washers) that contribute to the powerloss of the system to effectively predict the transmission efficiency. The evaluation and validation of the power loss models of the individual components is done by setting up analytical models on MATLAB with reference to the literature and comparing with the results from submodels designed in ROMAX. The most suitable models with the closest correlation to the experimental test results are selected for analysis of the system model. The efficiency of the system model is compared with the results from the test bench. The transmission system is also simulated in the WLTP cycle to analyse the operating points on the efficiency map.