Hyper-high-speed for electric vehicles to achieve maximum ranges.


Speed4E is the follow-up project of the already successfully completed research project Speed2E.
The general goal of Speed2E was the development, optimisation and setup of a high-rev-drivetrain, as well as the examination of its suitability for use in electrified automobiles. Increasing the driving speed of electric machines has the potential to significantly improve their power density and the overall efficiency of the vehicle.
Today’s electric vehicles are powered by machines with maximum driving speeds between around 10,000 rpm and about 15,000 rpm. With the increase in engine speed of up to 30,000 rpm, the volume of the active components, its mass as well as its price, could be reduced by about 30%. Therefore, the power density, the efficiency and the economic viability of electric automobile drivetrains were considerably raised.
The project objectives for Speed2E were accomplished: both sub-transmissions of the drivetrain were operated with a speed of up to 30,000 rpm, driving cycles could  be implemented and tested at the test-rig.


 Figure 1: Speed2E Drivetrain


Figure 1: Speed2E Drivetrain


In Speed4E, the goal is to reach and investigate even higher driving speeds,
in particular, driving speeds of up to 50.000 rpm are to be reached at the two test-rigs in Munich and Hanover, while a maximum motor speed of 30,000 rpm is pursued for safe operation in two vehicles. Hence, while developing a highly integrated, compact and power-dense drivetrain, a great focus will be put onto its NVH-behaviour and, especially, efficiency.

To achieve these ambitious goals, many aspects have to be taken into detailed account and, amongst others, these very challenges have to be faced:

The project goals for the hyper-high-rev drivetrain are in particular: