Abstract: An anti-lock braking system is specifically designed for a motor vehicle having four-wheel drive and a device for shifting between two-wheel and four-wheel drive incorporating a lockable central differential. Additional differentials at the front and rear axles may also be locked to avoid wheel spin. The anti-lock braking system produces a brake pressure reduction signal when the wheel speed falls below a reference value. In accordance with the invention the reference value is varied in dependence upon whether the vehicle is shifted into two-wheel or four-wheel drive, in dependence upon the engagement of the central differential lock, and/or in dependence upon the engagement of the other differential lock(s).

Abstract: A method of controlling the brake pressure in an antilock (ABS) vehicle brake system provides for adapting the wheel at which the brake is applied to the optimum course of the coefficient of friction/slip curve by determining the rotational retardation of the braked wheel, upon initiation of a braking action, after given time intervals each and comparing it with the rotational retardation of the preceding time interval. Moreover, the brake pressure is varied in response to the result of the comparison. The renewed acceleration of the retarded wheel also is monitored accordingly so as to effect further lowering of the brake pressure if the renewed acceleration or the gain in acceleration is too small.

Abstract: To counteract the tendency of over-steering when a vehicle operates in a curved path, and one of the wheels--typically the wheel at the inner side of the curve exhibits a tendency to block and, then, braking pressure is reduced to one of the front wheels only, the braking pressure applied to the rear wheel or wheels is reduced. If braking pessure is reduced to both of the front wheels, braking pressure being applied to the rear wheels is controlled, independently, in accordance with anti-brake lock control considerations, which have priority over dropping of braking pressure to prevent over-steering.

Abstract: An automotive engine forming part of a motor vehicle is controlled to avoid slipping or spinning of a driven wheel by controlling the maximum rate of change of fuel which can be supplied to the engine, for example, by limiting the speed of deflection of a throttle flap (6) driven by a servo motor (7). The deflection speed, limited for example by a voltage divider (14) can be controlled as a function of operating parameters of the engine or the vehicle, for example, vehicle speed (V.sub.F), engine speed (n.sub.M), engine loading or a percentage of engine loading, actual wheel slip, actual angle or deflection position of the throttle flap, and the like. Further, non-linearities between deflection of an operator actuated pedal, such as a gas pedal (1) and actual deflection of the control flap (6) can be compensated for, for example, in a difference forming circuit (9) providing an output error signal for the servo motor (7) or by software, e.g.

Abstract: To permit operation of an anti-skid or anti brake-lock system with wheels having dual braking cylinders, controlled by separate braking valves, control signals to control separate brake valves (V.sub.11, V.sub.12) at respective sides of the vehicle are derived for a first braking system (I) in accordance with well known technology, based on wheel acceleration, deceleration and the like, processed in an anti-skid control unit (9), and a second braking system, controlled by a single valve (V.sub.2), is provided connected to the second braking cylinders in both wheels. The control signals for the second valve (V.sub.