6. Internationales Stuttgarter Symposium

Abstract

The electrification of automotive powertrains is one of the key factors of meeting the development targets for fuel consumption and emissions. Both with and without the use of plug-in technology, powertrain hybridization assists the internal combustion engine in operating in optimal conditions and enables the recuperation of kinetic en- ergy during braking. The technology thus helps to increase fuel efficiency and reduce exhaust gas emissions, and – depending on the concept – offers the possibility of run- ning in full electric mode to avoid local exhaust emissions without the range limita- tions of full electric vehicles. Besides these aspects, powertrain electrification offers many possibilities for increasing longitudinal and lateral vehicle dynamics [1]. How- ever, in view of the wide range of variants and concepts of hybrid electric vehicles, finding optimized setups often poses a challenge due to the varying boundary condi- tions, different cases of application, as well as interdependent vehicle subsystems. In this case, optimization processes and tools assist in finding the best compromise, tak- ing into account all the various constraints. Frontloading with early integration of all the relevant subsystems of hybrid electric vehicles (HEV) is one of the key factors of an efficient development process. This process starts with simulation runs to investigate vehicle concepts and operating strat- egies, using different powertrain topologies or components. However, even in this early stage of development, simulation results have to be evaluated and decisions will be made based on the results of this investigation. For this reason, it is crucial to ex- amine the performance of the overall system, as well as the functionality and interac- tion of all relevant subsystems, in realistic scenarios and conditions in order to meet the final development targets. In this paper, an open integration and test platform is used for the multi-objective op- timization of the powertrain concept of a hybrid vehicle. This was done for different driving scenarios and driver types and taking into account longitudinal and lateral ve- hicle dynamics. A comparative study of fuel efficiency and performance for a hybrid- electric powertrain with different battery sizes and operating strategies was made, us- ing the FMI approach to integrate a detailed vehicle powertrain model into a compre- hensive full-vehicle model driven by a virtual driver on a virtual road.