Development of an Equivalent Consumption Minimization Strategy (ECMS) for a High-Performance Hybrid Electric Vehicle

This master thesis, carried out in Powertech Engineering Srl and commissioned by Aston Martin Lagonda Global Holdings plc (AML), concerns an analysis aimed at minimizing the fuel consumption of a high-performance Hybrid Electric Vehicle (HEV). In a HEV one or more Electric Machines (EMs) are added to a conventional Internal Combustion Engine (ICE) in order to save fuel and reduce CO2 emission, but the powertrain complexity is nevertheless increased. Thus, in a hybrid powertrain, the additional energy reservoir introduces an additional degree of freedom, and the benefits provided by the hybridization can be fully exploited only by means of an ad hoc powertrain control strategy. In the literature, several Energy Management Strategies (EMS) have been proposed in order to control the power split among the actuators. The Equivalent Consumption Minimization Strategy (ECMS) is one of the most promising techniques among them. Thus, it can generate results not so far from the optimum but can be, at the same time, theoretically implementable in an Electronic Control Unit (ECU). In this approach, the electrical energy, used by the EMs, is converted into a virtual fuel con-sumption and summed to the real one to obtain an equivalent fuel consumption. For each time-step, the entire range of possible power split between ICE and EMs is examined and the equivalent fuel consumption is computed in each case; then, the scenario which minimizes fuel consumption is chosen. This dissertation is focused on the development of an ECMS control for a high-performance HEV aimed at minimizing fuel consumption and, at the same time, achieve performance close to the optimality. Different ECMS strategies have been proposed and integrated into the virtual prototype performing type approval test cycles - New European Driving Cycle (NEDC) and Worldwide Harmonized Light Vehicles Test Procedure (WLTP) - and highly dynamic racetracks. In conclusion, this disquisition constitutes a feasibility study carried out for the AML on the exploitable power split strategies for a high-performance HEV. Hence, diverse strategies have been tested and the arguments for and against each of them have been scrutinized.