Steering control method for a motor vehicle with a differential

Abstract

A steering control method for a motor vehicle with a differential. The quantity and direction of a torque displacement in the state in which restricting means is locked are calculated. When the direction of the torque displacement is from an outside wheel to an inside wheel, a restricting torque is set at zero. On the other hand, when the direction of the torque displacement is from the inside wheel to the outside wheel, the ratio between the load displacement magnitudes of a front axle is calculated. A front axle driving torque is calculated from a transmission gear position, an engine speed and a throttle opening degree. The restricting torque is calculated so that a torque distribution to the inside and outside wheels may become substantially equal to a load distribution to them. The correction amount of a steering assist force is calculated from the restricting torque, and the mass offset of a wheel tire, the diameter of the wheel tire and a steering gear ratio. A hydraulic controller is driven on the basis of the restricting torque calculated above. A steering correction controller is driven on the basis of the correction amount of the steering assist force calculated above.