Energy Management Strategy for A CVT Hybrid Electric Vehicle Based on Dynamic Programming

Hybrid electric vehicles (HEVs) equipped with continuously variable transmission (CVT) show dramatic improvements in fuel economy and driving performance because they can continuously adjust the operating points of the power source. In this paper, the dynamic model of CVT based hybrid electric vehicle is established, and the dynamic programming algorithm is adopted to find the overall minimum of the fuel consumption, the strategy takes the battery SOC as the state variable, the CVT speed ratio and the torque distribution between motor and engine as control variables. In order to verify the effectiveness of the control strategy, Simulation experiments have been performed under 4 different driving cycles. The results show that, compared with the instantaneous optimization, the overall fuel consumption is significantly improved under various standard driving cycles.