Abstract: Coordinated optimization for parameters of hybrid electrical vehicle(HEV) powertrain and control strategy is the key to improving overall performance of power-split dual-mode hybrid electric bus. Aiming at the problems of high difficulty and long solution period for the optimization algorithms such as multi-objective genetic algorithm, particle swarm optimization and simulated annealing, the vehicle dynamic performance and battery SOC balance are taken as constraints, and the fuel-electricity conversion factor is introduced into the objective function. An integrated optimization method for design parameters and control parameters using multi-island genetic algorithm(MIGA) is proposed. The simulation have been carried out based on the Isight software, and the results show that on the premise of ensuring the power performance of vehicle and balance of battery SOC,the equivalent fuel consumption of the system is reduced by 0.21 L/100 km in the cycle of typical Chinese city, and the corresponding fuel saving ratio is 1.3%. The engine operating points move to the high load areas, and the working condition is improved. The efficiency of motor MG1 and MG2 is improved to different degrees, which demonstrated the effectiveness of the optimization algorithm in this work.

Key words: vehicle engineering, dual-mode power-split hybrid electric system, Isight software platform, multi-island genetic algorithm, integrated optimization