This conference paper was submitted for presentation at the NAFEMS World Congress 2025, held in Salzburg, Austria from May 19–22, 2025.

Abstract

With electric drivetrains becoming more common throughout various markets and territories as an alternative to legacy drivetrain power delivery systems, there has been a significant shift in the underlying needs for development and analysis of solutions. Simulations governing such development range anywhere from systems to electromagnetic to multiphase fluid analyses, and each analysis may have bearing on design choices that affect other analyses and cascade throughout the design process. Thus, combining and leveraging such analyses in tandem is a crucial consideration for effective development. This presentation showcases the engineering of a new electric drive for the Simrod vehicle. Simrod is owned by Siemens and based on a vehicle from Kyburz, a Swiss company that develops and produces high-quality electric vehicles for mobility markets and private individuals. It is a two-seats, 600kg electric vehicle with a maximum speed of 120kmh and an expected range of 180km. Engineering for the Simrod electric drive covers the V-cycle of development for a racing variant of the Simrod drive which considers specific constraints relevant for racing conditions, in particular thermal management. A complete system model for the vehicle is used to translate whole-vehicle requirements down to electric drive specific requirements, which include the motor, inverter, and transmission. Details of thermal management simulations are presented, and comparison of various cooling solutions and their corresponding simulation goals and considerations are given. Particularly, a spray cooling approach for thermal management is considered and analysis is presented. Alternative cooling configurations are discussed and weighed as alternatives to the design. Because fluid and thermal simulations typically incur significant computational cost, special attention is paid to simulation speed-ups while maintaining an adequate level of accuracy; additionally, if significant a significant speed-up can be obtained with a tradeoff of accuracy, such analysis is also shown. Several variations of the thermal analysis approach are compared, with general suggestions for simulation methodology being provided both for fluid and solid thermal systems. An overview of feasible approaches is summarized, and their performance is discussed.