Title: On the influence of the thermal demand on the overall efficiency of future drive train architectures for passenger cars

Authors: Claude Bouvy; Thomas Lichius; Peter Jeck

Addresses: Forschungsgesellschaft Kraftfahrwesen mbH Aachen, Steinbachstrasse 7, 52074 Aachen, Germany. ' Institute of Automotive Engineering, RWTH Aachen University, Steinbachstrasse 7, 52074 Aachen, Germany. ' Institute of Automotive Engineering (ika) RWTH Aachen University Steinbachstr. 7 D-52074 Aachen, Germany

Abstract: A new indicator for primary energy to wheel efficiency of different drive train architectures is derived, taking into account the thermal demand for cabin heating and all losses of the overall conversion chain. Battery electric vehicles are chosen as reference. The indicator is applied to an actual and a future scenario for three different car concepts: pure combustion engine, full hybrid and plug-in hybrid. In general, the actual scenario shows higher efficiency of all three car concepts compared to electric mobility. This is mainly due to the benefit of the combustion engine as a decentralised cogeneration unit. With an improved future electricity generation, the efficiency of electric drive is improved, resulting in the best efficiency of the plug-in hybrid. Furthermore, the time dependency of the power to heat ratio for different climatic conditions is analysed for the new European drive cycle and the influence on the new indicator is discussed.

Keywords: battery electric vehicles; decentralised cogeneration; internal combustion engines; electric mobility; holistic dynamic car models; vehicle modelling; hybrid drivetrains; overall efficiency; passenger cars; primary energy; well to wheel analysis; thermal demand; cabin heating.

DOI: 10.1504/IJEHV.2011.043873

International Journal of Electric and Hybrid Vehicles, 2011 Vol.3 No.3, pp.293 - 307

Received: 20 Jun 2011
Accepted: 07 Nov 2011
Published online: 27 Nov 2011 *

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