Analytical Methodology to Derive a Rule-Based Energy Management System Enabling Fuel-Optimal Operation for a P24-Hybrid 2021-01-1254

The electric range of plug-in hybrids as well as the installed electric power has steadily increased. With an electric power share of more than half of the overall system power, concepts of hybrid electric vehicles with at least two electric machines come into focus. Especially the concept of adding an individual electric axle to a state-of-the-art parallel hybrid, such as a P2-hybrid, is promising. However, the system complexity of a so-called P24-hybird increases significantly because the number of possible system states rises. This leads to an increased development and calibration effort for an online energy management. Especially a transfer from an optimized operating strategy to a rule-based energy management is challenging. Thus, a development framework for the calibration of an online energy management system (EMS) which is as fuel efficient as possible is needed. This development framework should ideally be applicable to different hybrid configurations because car manufacturers will most likely have different hybrid topologies in their portfolio. Hence, the applicability of a methodology for P2-hybrids is investigated. This paper shows that the same fundamentals for P2-hybrids can be used and that a development framework independent of the hybrid topology can be established to derive a rule-based calibration, which ensures fuel-optimality. Furthermore, the fuel-optimal operating strategies of a P24-, a P2- and a series hybrid is analyzed and compared to each other.