Abstract
The legal requirements regarding fuel consumption and exhaust emissions of vehicles have been tightened worldwide during the last years. As a result, those requirements cannot be fulfilled with conventional powertrain systems solely. Plug-in hybrid electric vehicles (PHEVs) offer high fuel saving potentials, because longer distances can be driven purely electrically. Due to the high variety of PHEV topologies and operation strategies, powertrain development is getting considerably more complex. There is a crucial conflict between consumption and emission reductions going along with ambitious requirements regarding driving dynamics and comfort. To manage the complexity and increase the efficiency in powertrain development, a simulation and optimization tool based on the IPEK X-in-the-Loop approach was developed in a research cooperation between IPEK – Institute of Product Engineering at Karlsruhe Institute of Technology (KIT) and the BMW AG. As a basis for computer-aided optimization regarding consumption, emissions and customer value, this article focuses on the development and verification of sub-models for consumption and exhaust emission calculation as well as on the sub-model integration into the existing simulation tool. The suitability of the model for optimization is demonstrated exemplarily by simultaneously minimizing fuel consumption while complying with the emission limits in the FTP72 test cycle.
KEYWORDS – Plug-in hybrid electric vehicles, fuel consumption, exhaust emissions, operation strategy optimization, simulation