Preliminary design and prototypic assembly of an electric truck drive axle

Authors

S. Köller, R. Uerlich, D. Swierc, G. Witham, M. Gerigk, L. Eckstein - ika, RWTH Aachen University

Summary

The present research gives an overview of the process of designing and building prototypes of electric axles for heavy-duty vehicles at the Institute for Automotive Engineering (ika) of RWTH Aachen University. This overview starts with a brief presentation on the road transport and logistics industry. The expected growth of this market motivates - together with legislative regulations on tailpipe emissions - the development of electrically driven trucks. Thus, future trucks that have a powertrain containing one or more inverters, electric machines, and transmissions. A methodical approach to de-signing and evaluating electric powertrains is explained in the following. Within the developed methodology, powertrain concepts can be evaluated on the vehicle level in longitudinal simulations. By this approach, the energy demand of the vehicle may be derived and compared to different powertrain concepts for the exact vehicle. The presented approach was used to develop and build a prototype of an electric powertrain for a heavy-duty truck. The process and its results are presented, starting with a trans-mission synthesis followed by the validation of thermal simulations with measurement data of a developed prototype. The resulting axle comprises two gears in one trans-mission part and a fixed ratio in the other part. It is propelled by two electric machines, one with a lower power of 125 kW and one with a higher power of 250 kW, which can be used individually or combined. The paper closes with an outlook on current projects at ika concerning the electrification of heavy-duty trucks. The projects have broadened the field of research from focusing on the powertrain level to analyzing alternative power supplies such as overhead-line systems and developing innovative drive systems with purpose-designed chassis to break up historical boundaries of convention-ally propelled trucks such as rigid axle bridges.