Powertrain Efficiency

The efficiency of the DE‑REX powertrain was investigated based on test bench measurements of the electric energy consumption.

The comparative results starting from a state of the art fixed-speed transmission BEV (BEV‑1GR) up to the DE-REX with the design boundary conditions of a fixed launch torque (>2500 Nm) and a fixed maximum vehicle speed (180 km/h) are shown in the following.

The results show that a state of the art BEV‑1GR has the highest electric energy consumption. The EM-Downsizing variant with reduced system power and fixed-speed transmission does not meet the requirements concerning launch torque.

Picture: IMS

But it shows in a first step that a significant share (8.3 %) of the overall efficiency advantage of a DE‑REX is due to the substantially lower system power. In order to meet the requirements with reduced system power, at least two speeds are necessary (Multi-Speed-AMT). With the Multi-Speed AMT, however, gear shifts cannot be carried out without interruption of traction force. The DE-REX approach offers an alternative solution to fulfill comfort requirements and further contributes with additional operating modes to an increased overall efficiency of in total 10.7 % compared to the state of the art BEV.