Multiphysic model-based design and fuel consumption optimization of a series-hybrid electric vehicle (SHEV)

The growing interest in the decarbonization process has led to a rapid growth of electrification strategies in the automotive industry. In particular, OEMs are pushing towards the development and production of efficient hybrid vehicles as a transition solution towards the deployment of electric vehicles. Indeed, research on energy management control strategies for hybrid vehicles is exploding in popularity. In this context, this thesis focuses on the development of a high-performance series-hybrid electric vehicle model, developed on Matlab Simulink environment, in order to simulate the powertrain and test and optimize different control strategies with the aim of minimizing fuel consumption. After a careful benchmarking analysis, which was useful for dimensioning the components in an initial map-based modelling phase, the final goal of the thesis was to implement two types of control strategy (SOC rule-based and ECMS optimization-based) for energy management and implementation of the system components. In addition, the vehicle model is able to switch from one driving mode to another: the cruise mode forces the internal combustion engine to operate in such a way as to minimize fuel consumption; during the sport mode, the internal combustion engine is able to operate at torque and RPM values that guarantee the best possible engine sound quality. Based on the demand for sport mode, a virtual gear shift logic has been implemented, considering that the engine is not connected to the traction. Several models, characterized by increasing levels of complexity, are simulated in quasi-dynamic mode, choosing the correct simulation time step to capture all vehicle dynamics. The driving cycle input of such forward simulator are the WLTP homologation cycle, the range driving cycle and the Nϋrburgring track driving cycle. Finally, the selection of the best control strategy is achieved considering the fuel consumption and the vehicle range.