Trip-based control strategy for simple and efficient use of plugin hybrid electric vehicles

The optimal management of plugin hybrid electric vehicles (PHEVs) energy efficiency and range autonomy is strictly dependent on the battery discharge rate which may expressed by its state of charge (SOC) time variation. In fact, vehicle efficiency is strongly influenced by the possibility of controlling the SOC discharge rate as well as of the trip distance and the availability of recharging facilities along the itinerary. In the given scenario, the accurate control of SOC discharge rate to complying with trip-based target values of the SOC (which allow for taking into account the availability of external recharge station opportunities) appears as a key aspect to be investigated. In this paper, we propose a robust and efficient optimised control strategy, implementable in a state of the art ECU. The power-split strategy may be defined for any given trip also taking into proper account the vehicle speed over the route. The main target demonstrated in this paper is the request of reaching a target SOC (SOCL) at the end of the trip although the application to other objectives (e.g., minimisation of emissions) is also theoretically feasible. The proposed strategy is implemented and tested in a PHEV vehicle model designed and realised at the University of Rome Tor Vergata, and validated by using experimental data directly acquired over several standard cycles and real-world routes.