Abstract
A clutch actuator pressure control scheme is investigated for a soft-type hybrid electric vehicle which adopts a metal belt CVT to improve the restart response while maintaining the driving comfort. To evaluate the vehicle performance at start, dynamic models of the CVT hydraulic control system, wet clutch pack, CVT variator and drivetrain are obtained. A AMESim vehicle performance simulator is developed based on the dynamic models and validated by comparing the vehicle test results. Using the simulator, performance of the restart delay and driveshaft torque is investigated. It is found from the simulation results that the vehicle restart response depends on the clutch pressure build up time to the point where the clutch torque begins to overcome the vehicle road load and comfort driving comfort at restart is directly related with the rate change of the clutch pressure.
Keywords: CVT, Hybrid Electric Vehicle, Clutch, Restart Respones