Simultaneous optimisation of fuel consumption and emissions for a parallel hybrid electric SUV using fuzzy logic control

Energy control strategy, especially for the driving power management, is one of the main issues in the design of Hybrid Electric Vehicles (HEVs). In order to reach the target of simultaneously optimizing both fuel consumption and emissions, an environment friendly and efficient Fuzzy Logic Control Strategy (FLCS) for a Parallel Hybrid Electric SUV is depicted in this paper. In this control strategy, an optimal torque provided by the Internal Combustion Engine (ICE) according to the driving conditions is firstly evaluated based on the ICE characteristics through dynamically choosing a set of weights on fuel consumption and emissions. Then, with the consideration of control-state constraints and other power components’ characteristics, the acquired optimal torque is modified/ corrected by a fuzzy logic controller which has three fuzzy inputs: State of Charge (SOC), the driver’s request driving torque and Electric Motor speed. Therefore, the actual required output torques of the ICE under different driving conditions are figured out. The proposed control strategy were modelled in Simulink and incorporated into the vehicle simulation software Advisor. The simulation results demonstrate that the proposed control strategy is more effective in overall comparing to the conventional Electric Assist Control Strategy (EACS).