Systematic synthesis and multi-criteria evaluation of transmission topologies for electric vehicles

The focus on the expansion of the electrification of vehicles becomes stronger. Thus, the development process of powertrains of those cars needs to be more dynamic to react to the new challenges. One way to accelerate the development is to automate predevelopment and evaluation at an early stage. An automated method to synthesize transmission topologies and pre-design gears for the generated topologies for electric vehicles is presented within this paper. The method contains two internal evaluations—one after the topology synthesis and the second after the initial design of the gears. The results of the method are gear ratios and gear data for the single transmission steps of each topology. The inputs and boundary conditions can be easily changed and fitted to specific requirements for all use-cases. Here, the process is explained, and the methods' results are validated using state-of-the-art passenger vehicle transmission. As for electric trucks, no state-of-the-art electric powertrains exist; the method is subsequently applied to find topologies for a heavy-duty truck. Extracts of the results are presented. The application for trucks is carried out within the publicly funded research project “Concept ELV²”. In general, the method is capable of synthesizing transmissions for any given vehicle and motor combination.