Abstract: In order to reduce the pollution caused by a normal car at low speeds especially in the urban area, a parallel hybrid car with a metal belt-planetary gear continuously variable transmi-ssion (CVT) is researched. Compared to a normal electric car with gear transmission system it has many advantages such as a larger starting torque a lower power a lighter weight and so on. The simulation equations on the dynamic characteristic of electric car with a DC motor is established using bond graph theory. The control rules of the armature current of motor and ratio of continuously variable transmission are obtained. The design method of a parallelhybrid car is established.

Key words: Bond graph Simulation, Hybrid car Continuously variable transmission