Research on drivability control in P2.5 hybrid system

Abstract

The control of drivability in this paper contains the clutch start, the engine and motor anti-jerk control during tip in and tip out. First, the fast clutch start is divided into five phases as well as the smooth clutch start: the gear selection phase, the drag phase, the reduction phase, the injection phase and the gear engage phase. To avoid the jerk caused by the torque loss during the drag phase, the motor torque is defined to reserve in pure electric drive condition and to compensate the clutch torque. Second, the engine fast torque and slow torque anti-jerk control which contains enable conditions and torque ramp control based on overall wheel torque before filtering are presented. Third, the motor lash detection, brake detection, and anti-jerk control are introduced. Finally, the real vehicle tests are performed to show that the drivability system can greatly improve the driver’s comfort and reduce jerk during the clutch start, tip in and tip out process successfully. The fast clutch start time is reduced from 1.27s to 0.56s compared to the smooth clutch start. The smooth clutch start acceleration speed is reduced from 2.9 m/s^2 to 1.5 m/s^2 compared to the fast clutch start. The engine torque after filtering control during full acceleration changes from -0.6 m/s^2 to 1.8 m/s^2 and the motor torque after filtering control during 50% acceleration changes from 1.8 m/s^2 to -0.07 m/s^2 without obvious jerk.