Abstract: The torque distribution for four wheels is controlled corresponding to the operating conditions of a car. There are provided a plurality of control systems such as a system for controlling the torque distribution for front and rear wheels, a system for controlling the torque distribution for right and left wheels, and the like. When the torque required for predetermined torque distribution exceeds the excess torque of an engine, the priority of the control systems to execute the control is changed depending on a friction coefficient caused between the road and tires.

Abstract: In the case where the driving torque distribution for four wheels of a car is controlled correspondingly to a lateral acceleration of the car, there is selected either an actual lateral acceleration of the car detected by a lateral acceleration sensor or a lateral acceleration calculated on the basis of a steering angle and a car speed, of which absolute value is smaller, in order to execute torque distribution control. Thus, the turning of the car can be enhanced.

Abstract: Disclosed is a four wheel drive vehicle with four wheels drivable, which is provided with a first slip control apparatus for reducing a driving force to the wheels by operating a brake mounted on each of the wheels and with a second slip control apparatus for reducing a driving force to the wheels by reducing the engine output. Operation of only the first slip control apparatus or both the first and second slip control apparatuses is selectively carried out in accordance with the number of wheels which are detected to be slipping in an amount greater than a given degree of slippage. Particularly when such slipping wheels are two, the slip control is conducted by operating only the first slip control apparatus or both the first and second slip control apparatuses in accordance with control modes predetermined on the basis of six combinations in which such two slipping wheels out of the four wheels are combined with each other.

Abstract: The control apparatus eliminates the adverse effects upon a moving vehicle caused by interference between two control operations taking place at the same time. For example, the control of torque applied to the wheels simultaneously subjected to wheel slip control can cause competing contradictory instructions to be issued to control the rotation of the wheel. When a wheel undergoing slip control is instructed by the torque split control to increase torque, the torque split control is cancelled. When the torque split control decreases the torque applied to a wheel and the wheel continues to slip, the wheel is subjected to slip control and the torque applied is reduced to prevent slip. When a wheel undergoing slip control has increased torque applied, the slip of the wheel is monitored and the torque is reudced to bring the slip below a predetermined limit.

Abstract: In a four wheel drive vehicle adapted to drive all of the four wheels, a braking force is applied to the wheel which causes slipping while the output torque of the engine is increased in accordance with brake operation. A braking pressure adjusting unit is preferably provided with each of the four wheels which is arranged so as to separately and individually brake the wheel which slips.