Aachen engineers establish real-time connection between test benches for increased efficiency


In order to achieve significant time and cost reduction in the development process, engineering company FEV and the Institute for Combustion Engines at the RWTH Aachen University (VKA), Germany, have implemented a virtual connection between two test benches.

The test environment consists of spatially separated test benches, which are connected by a real-time deterministic EtherCAT connection.

“The dynamometers in both test benches are controlled in a way that achieves the equivalent system behavior of a real mechanical shaft,” explained Professor Stefan Pischinger, president and CEO of FEV Group and director of the Institute for Combustion Engines at RWTH Aachen University. “With this, an interaction is achieved – for example between engine and transmission – during the prototype phase before both components are able to be adapted, thus saving important development time.”

According to FEV, the test effort of modern hybrid drives is significantly higher when compared to conventional powertrains. The main reason for this, FEV says, lies in the higher number and more complex interactions of the components. At the same time, current trends in powertrain development – for example, road to rig approaches – result in the movement of significant portions of the development process from the vehicle to the test bench and, thus, into earlier project phases. Against this background, a new tool called the virtual shaft was developed in collaboration between FEV and VKA.

As well as saving time, benefits of networking the test cells with the virtual shaft include the provision of a protected test environment and high number of monitoring options for the individual test objects. With this scenario, damage to prototypes can be prevented. In addition, the virtual shaft allows the combination of hybrid powertrains that are not yet mechanically compatible and would otherwise have to be extensively adapted.

“In conventional development processes complexity increases step-wise as we move from a single component up to system testing in the vehicle,” said Dr Albert Haas, group vice president, test systems, at FEV. “First the e-motor, the engine and the transmission are tested separately in single test cells. The real interactions between the different components, though, cannot be evaluated until composite system testing can be accomplished on a full powertrain test bench.

“This step requires not only a change in the test environment, but also mechanical modifications and software changes. Therefore, this is usually performed in a later development phase, where either a vehicle or a complete powertrain is needed. The virtual shaft makes a valuable contribution to handling the increasing complexity of modern hybrid drives and provides the opportunity to make the development process more efficient.”

August 7, 2015


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John joined UKi Media & Events in 2012 and has worked across a range of B2B titles within the company's automotive, marine and entertainment divisions. Currently editor of Automotive Testing Technology International, Crash Test Technology International and Electric & Hybrid Marine Technology International, John co-ordinates the day-the-day operations of each magazine, from commissioning and writing to editing and signing-off, as well managing web content. Aside from the magazines, John also serves as co-chairman of the annual Electric & Hybrid Marine Awards and can be found sniffing out stories throughout the halls of several of UKI's industry-leading expo events.

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