A Novel Test Bed Setup for Method Verification on the Example of a Shiftable Electric Axis

Power unit (PU) is a collective term for combustion engines, electric motors and their combination (hybrid), as well as with and without transmission connection.

To allow the PU full electric drive application, in addition with a shiftable transmission, on a one axle test bed, IPG provided CarMaker/TestBed with new interfaces for an electric drive motor (full electric PU) and for the load machine (only one brake on the transmission’s output shaft). In the present case further customization became necessary to use the Transmission Control Unit hosted by IPG´s Xpack4-system beside the virtual representations of all missing vehicle components.

For the first time and as one target, the PU full electric drive application has been implemented in CarMaker/TestBed. In addition, a reduced test setup was provided, which is more cost-efficient and at the same time highly flexible. This will also allow further investigations to be carried out in the future (for example a pure electric motor in-the-loop).

In a project cooperation HMETC and IAV have created the full virtual environment simulation model as a basis for the method development for optimizing the driveability to form the branding characteristics of electrified powertrains as one of the central challenges for OEMs.

In the present application example, another target was to verify the developed simulation model in advance. Starting from a full virtual environment using CarMaker in combination with the Simulink-based transmission controls, the virtual PU was therefore replaced by the above-mentioned test setup.
A high correlation between simulation and testing was achieved. This shows that the focus should be on drivability at an early (pure digital) stage in the powertrain (advanced) development. Furthermore, digital real-world representations allow to analyze and optimize holistic systems in the following development stages and also the coherent software and hardware development (X-in-the-Loop) for the complete vehicle development.

The paper will present the test bed setup, our method on an exemplary shift element optimization and the results of early simulations compared to later test bed measurements.