The influence of mode change penalties on the comparison of hybrid drivetrain topologies

Wilco van Harselaar, Markus Brouwer, Stephan Rinderknecht, Theo Hofman

Research output: Contribution to journalConference articlepeer-review


Hybrid drivetrains are systems with complex behavior of which finding the optimal design is a problem with a large design space. To assess a design on efficiency over a driving cycle, a control strategy is needed. Introducing mode change and engine start penalties in the optimization of the control increases the accuracy of the results at the cost of increased computation time. Yet, due to the large design space of the design problem, computation time is critical. In this work, an extensive case study is presented to analyze the influence of penalizing mode changes and engine starts on the comparison of hybrid drivetrain topologies. Eight different drivetrain topologies are considered, including parallel, series-parallel, and multimode powersplit topologies. For these topologies, the control is optimized over two driving cycles using dynamic programming with and without penalties. The introduction of mode change and engine start penalties reduces the number of mode changes by a factor of three to five, and the number of engine starts by approximately a factor of three. Yet, the influence on the fuel consumption comparison between the topologies is small: the largest change in relative fuel consumption is 0.36 percentage points, with the average absolute change over both cycles being 0.15 percentage points. The computation time is increased by approximately a factor of 26 due to the introduction of the penalties. Therefore, in the context of the system level design of hybrid drivetrains, it can be argued that the additional computation time outweighs the minor increase in accuracy provided by mode change penalties.

Original languageEnglish
Pages (from-to)14141-14146
Number of pages6
Issue number2
Publication statusPublished - 2020
Event21st World Congress of the International Federation of Aufomatic Control (IFAC 2020 World Congress) - Berlin, Germany
Duration: 12 Jul 202017 Jul 2020
Conference number: 21

Bibliographical note

Publisher Copyright:
© 2020 Elsevier B.V.. All rights reserved.

Copyright 2021 Elsevier B.V., All rights reserved.


  • Drivetrain topology
  • Dynamic programming
  • Gear shift
  • Hybrid electric vehicles
  • Mode change
  • Multi-mode
  • Powertrain architecture
  • Powertrain design


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