Development of a Clutch Control System for a Hybrid Electric Vehicle with One Motor and Two Clutches

This paper describes a newly developed hybrid electric vehicle system incorporating one motor and two clutches. The mechanical system is connected in a sequence of the engine, the first clutch, the motor, the second clutch and the mechanical gears. The system can transmit driving torque with high efficiency because the friction and pumping loss of the engine are removed by releasing the first clutch. It is difficult for the system to reach the same level of driving performance as a conventional vehicle with an automatic transmission. The nonlinear characteristics of the first clutch are described along with its stroke control system. Bench test results are presented to show that the nonlinear characteristics are removed to achieve the desired stroke performance. Test results confirm that smooth and fast vehicle acceleration is achieved by controlling the torque capacity of the first clutch using the stroke control system.