Virtual Powertrain Simulation: X-in-the-Loop Methods for Concept and Software Development

Due to the increasing pressure on vehicle emission reduction, the development of powertrains is changing considerably. Hybridization offers a significant potential in this context, leading to increasing powertrain complexity, and thus to an increase in the number of the control functions to be developed and tested. Therefore, a seamless validation of the concepts in early development stages is necessary to enable cost and development time optimization. For these reasons, the virtualization of powertrain components has become a necessity in the development process, and simulation methods for concept and testing gained fundamental importance. In this context, this paper proves the potential of X-in-the-Loop (XiL)-based methods. In particular, the role of Model-in-the-Loop (MiL) methods in early stages of the development process is highlighted as a cost-effective way for the definition of the most efficient hardware and software functions and for the development of new hybrid powertrain architectures. As one example, a methodology based on XiL simulation and its heterogeneous model landscape of different powertrain topologies will be presented. Specifically, a MiL setup and the corresponding Engine-in-the-Loop (EiL) platform of a parallel hybrid (P2) powertrain have been successfully used for the development and testing of a new emission-optimized control strategy. The results show improvements of the strategy robustness, and significant benefits in terms of emissions reduction.