Scalable electric powertrain targets utility vehicles

February 03, 2015 //By Christoph Hammerschmidt
While many observers agree that electromobility is gaining traction (at least in the medium term), the development of commercial vehicles with electric powetrain continues to lag behind. Their powertrain is just too expensive, clumsy and heavy. Fraunhofer researchers addressed this problem by developing an optimised axle module with integrated motor for lower weight and development costs.

Within the ESKAM project, eleven research partners led by Fraunhofer Institute for Tool Machines and Forming Technology (IWU) developed an axle module for commercial vehicles. Motor, power electronics and transmission are integrated in a single compact casing. The casing can be incorporated into the target vehicle by means of a frame design, which also has been developed in this context.

The module offers numerous advantages. Besides high power density it offers very high torque which translates into good acceleration. While most motors for electric vehicles offer a rotation speed of 10.000, or 15.000 rpm at the utmost, the ESKAM motor can be driven up to 20.000 rpm. "When we started development some three years ago, we were the only ones that dared to implement such high rotational speeds", remembers IWU project manager Hans Bräunlich.

The most striking advantage of the ESKAM design however is a different one: The consortium did not only develop the axle module but also the technology necessary for series production. "Due to our innovative approach, the modules can be manufactured flexibly", Bräunlich says. "Low quantities are feasible at economic conditions just as good as large quantities".