The influences of energy storage and energy management strategies on fuel consumption of a fuel cell hybrid vehicle

A new road vehicle powertrain simulator is presented and applied to vehicle dynamics. The electric motor, the fuel cell, the energy storage system (ESS), the braking rules, and the energy management strategy (EMS) heuristic rules are modelled. The role of the EMS and the ESS in the fuel consumption of a fuel cell hybrid vehicle is analysed, and the influence of the duty cycle on the results is examined. Simplified EMS if-then heuristic rules are used to describe powertrain behaviour. The developed simulator is used in an actual application, a fuel cell hybrid taxi, performing over a standard driving cycle, the NEDC, and over a specific duty cycle, the London DC, both with zero grade but with different dynamics. The results indicate that the EMS can have a significant impact on hydrogen consumption, leading to 7–10% less energy consumption because of the EMS improvements. Additionally, the EMS has less impact on the duty cycle when the vehicle is subjected to a more dynamic profile. The design of the EMS will depend on the particular ESS. The achieved 5% impact in the same duty cycle, especially with the hybrid ESS, clearly indicates the importance of optimizing the EMS according to the ESS components and vehicle usage.