Abstract: In order to reduce production cost, improve control effect of saving fuel and reducing emission, a new super-mild hybrid transmission system is developed to over the limitation of the existing mild hybrid electric vehicle (HEV) which has not the working condition as the pure electric drive. The new one is based on continuously variable transmission (CVT) with reflux power, which features wide speed ratio range, high transmission efficiency and big loading ability. Through adoption of the new transmission mode and match control strategy, the match design theory and control method of hybrid transmission system based on large speed range are researched. The test results show that the super-mild HEV saves fuel by 13.02%, in which 1.88% is contributed by the continuously variable transmission (CVT) with reflux power.

Key words: Continuously variable transmission, Control strategy, Hybrid transmission, Simulation analysis