Photo Credit: KIT


MTZ Project Reports. Thermal tests in coupled test bench operation

The development of hybrid electric powertrains requires an increased testing effort. For this reason, a method for testing hybrid electric powertrains with a focus on thermal tests was developed as part of a project at the Karlsruhe Institute of Technology and demonstrated in a setup consisting of two interacting combustion engine and electric motor test benches.

Electrification of conventional powertrains can reduce fuel consumption as well as pollutant emissions in order to comply with increasingly strict emissions legislation. With the upcoming Euro 7 standard, an extended temperature range, probably from -10 to +45 °C [1], will also come into focus for vehicle approval. The associated increase in complexity further increases the development effort for hybrid electric vehicles (HEVs). In addition to tests on the road, a wide range of analyses must be carried out on component, powertrain and vehicle test benches. Here, the virtual coupling of test benches can contribute to the reduction of cost-intensive testing efforts, as demonstrated in [2] and [6].

This approach was further developed in the present project in order to test virtual-physical hybrid powertrains. In addition to developing requirements for the networking of test benches, the thermal behaviour of the individual components was investigated in the project. In this paper, the test benches and the structure of the simulation model are presented and results of the thermal tests from paired operation are shown.

The project presented shows the virtual coupling of two real prime movers (VKM, EM), each installed on a test bench and investigated with regard to their thermal behaviour. With the help of a vehicle simulation environment and detailed simulation models, additionally required components or control units were simulated and the exchange of relevant parameters between the test benches and the simulation was guaranteed. The necessary communication was implemented via UDP/IP with the DCP standard. The results of the thermal tests prove a good interaction of real and virtual components. The test benches coupled in this way offer in particular the possibility to realistically test the latest control strategies taking thermal processes into account.


[1] Advisory Group on Vehicle Emission Standards: Additional technical issues for Euro 7 LDV. Online:, aufgerufen: 28. Mai 2021
[2] Andert, J.; Huth, T.; Savelsberg, R.; Politsch, D.: Testen von Antriebssträngen mit der virtuellen Welle. In: ATZextra Prüfstände und Simulation für Antriebe 20 (2015), S. 30-35
[6] Nickel, D.; Stelter, E.; Mittmann, W.; Heiduczek, T.: Vernetzte Test- und Simulationsumgebungen. In: MTZextra 23 (2018), S. 18-2

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The FVV in the MTZ and ATZ magazine

Results from Industrial Collective Research are accessible to all interested parties and thus final reports of FVV research projects will be presented to the public at our conferences in spring and autumn. In order to further promote the transfer of knowledge and the expansion of the prime movers innovation network, we publish articles on individual projects with particularly interesting new insights in the world's leading specialist magazines for the engine and vehicle industries. MTZ / ATZ and FVV have been working together successfully in this field for many years.

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