Abstract: In order to solve the problems of large motor torque shock and short battery life when the city battery bus starts or accelerates, this paper designs a new dual-shaft parallel electro-hydraulic hybrid system for a certain type of electric bus running in Chengdu to study the improvement of the comprehensive energy utilization rate by adjusting the working state of the motor under typical working conditions. Based on the co-simulation of AMESim and MATLAB/Simulink-stateflow software, the vehicle and control model are established and the rule-based dynamic optimization energy management strategy is set up. The dynamic performance and energy utilization characteristics of Chinese City Bus Cycle(CCBC) and field investigation driving conditions of this kind of bus are analyzed. The core problems of energy coupling of electro-hydraulic hybrid system are studied experimentally, which verifies the correctness of the design thought and the simulation model. The results show that under the premise of satisfying the demand of dynamic performance, the designed electro-hydraulic hybrid system can effectively improve the distribution of the motor’s operating point and greatly reduce the peak torque shock. Under CCBC conditions, the peak torque is reduced by 33.8%, and the driving range is increased by 30.6%; while under field investigation conditions, the peak torque is reduced by 33.0%, and the driving range is increased by 20.0%

Key words: battery bus, electro-hydraulic hybrid, motor working efficiency, torque characteristic, energy efficiency