Four-wheel drive switching control device for electric motor type four-wheel drive vehicle

摘要

PPROBLEM TO BE SOLVED: To propose motor torque control at the time of four-wheel drive switching, which reduces play of a decelerator without causing gear rattling noise at the time of four-wheel drive switching and prevents clutch engaging shock. PSOLUTION: In a play reduction period A, a motor torque command value Tm is set to a small value (the upper limit value of a motor torque that causes no problem with gear rattling noise) so that gear rattling noise preventing effects are achieved. A moment t1 when a motor speed Nm is decreased due to a load received on the electric motor in the play reduction is determined as a moment when the play reduction of a decelerator ends, and afterwards, the motor torque command value Tm is set to a large value (the lower limit value of motor torque necessary for engaging clutches) so that clutches are engaged by cam operation. PCOPYRIGHT: (C)2010,JPO&INPIT