Abstract: The existing hybrid driving systems are studied. One kind of hybrid four wheel driving system is brought forward that is based on dual-rotor electric motor. This system is composed of mechanical transaxle and electric transaxle. By synthetically controlling of the two transaxles, the vehicle can be driven by either one or both of the two transaxles. The electric transaxle is composed of one dual-rotor electric motor and reducer and rotation direction exchange devices. It has the ability of driving, differencing and energy feedback. On the basis of performance theory of the dual-rotor electric motor, the mathematic model is established. Furthermore, the simulations of load mutation and swerve are carried out. Taking some sport utility vehicle as an example, the comparison simulation between prototype and novel type vehicle is done on the Matlab/Simulation calculating platform. The simulating results show that the driving performance of the novel vehicle is also the same as the prototype vehicle and the fuel economy is better than the pro-totype vehicle. The fuel consumption of the novel vehicle is 10.58% and 21.87% less than the prototype vehicle per 100 km based on the highway and city running cycle.

Key words: Dual-rotor electric motor, Four wheel driving, Hybrid electric vehicle