Abstract: In order to improve an electronic system for a motor vehicle which comprises an electronic controller which is coupled via an electronic communication system to electronic controllers of other electronic systems of the vehicle in order to co-operate through data exchanges with the other electronic systems of the vehicle, wherein electronic sensor devices for controlling and/or regulating operating states of the vehicle detect quantities which are related to the operating states of the vehicle, so as to obtain cost and functional advantages, it is proposed that at least one of the electronic sensor devices be accommodated in one of the electronic controllers.

Abstract: In order to improve an electronic system for a motor vehicle which comprises an electronic controller which is coupled via an electronic communication system to electronic controllers of other electronic systems of the vehicle in order to co-operate through data exchanges with the other electronic systems of the vehicle, wherein electronic sensor devices for controlling and/or regulating operating states of the vehicle detect quantities which are related to the operating states of the vehicle, so as to obtain cost and functional advantages, it is proposed that at least one of the electronic sensor devices' be accommodated in one of the electronic controllers.

Abstract: A method of controlling the brake pressure in an anti-lock brake system of a dual-track vehicle wherein pressure raising pulse trains are applied to the brakes of the rear wheels of the vehicle provides for modified "select-low" control of a kind with which the brake of the one wheel which first is instable on the rear axle is fed with a pressure raising pulse train having a smaller mark-to-space ratio or pulse duty factor than the pressure raising pulse train applied to the brake of the other, the stable wheel of the rear axle.

Abstract: A method of controlling the brake pressure in an anti-lock vehicle brake system provides for short distances to stop to be reached even with greatly differing mass moments of inertia by calculating the pressure reduction period of a control cycle currently under way as the product of a first factor and a second factor. The first factor depends on the pressure reduction period in the preceding control cycle, and the second factor depends on the maximum re-acceleration of the wheel in the preceding control cycle.

Abstract: In a method of controlling the brake pressure of a vehicle brake system equipped with anti-lock protection it is provided to measure the slip and/or rotational retardation of a wheel whose brake is applied and to compare each measured value with a given threshold value so as to lower the brake pressure if the threshold value proves to have been surpassed. Undesired pressure reductions can be avoided by increasing the threshold value for given periods of time from a basic value (S.sub.G) and subsequently decreasing it again. At a point in time T.sub.1 at which the rotational retardation of the braked wheel is greater than a value corresponding to a physically feasible slowdown of the vehicle the threshold value is increased abruptly, to be decreased thereafter according to a predetermined function of time. During the lowering of the threshold value the change in speed of the retarded wheel is measured over given intervals of time .DELTA.T and compared with the instantaneous higher threshold value.

Abstract: An anti-skid brake control system for a motor vehicle includes wheel sensors for producing signals representative of the rotational speed of each road wheel; an evaluation circuit responsive to the wheel speed signals for determining a reference speed that approaches the speed of the vehicle and for producing brake pressure control signals, in dependence upon the reference speed and the road wheel speeds; and a brake pressure controller responsive to the brake pressure control signals for varying the brake pressure applied to the road wheels. The evaluation circuit includes means for determining the vehicle speed from the average increase of the reference speed and this vehicle speed, so determined, is used to determine an increase in the value of the reference speed during periods of braking instability.

Abstract: In a method of controlling the brake pressure in the rear wheel brakes of a double-track vehicle, wherein the rotational speeds at least of the rear wheels are measured and the brake pressure is lowered, kept constant, or raised, depending on the unstable or stable states arising at the individual rear wheels, the pressure in the brake of a stable rear wheel being approximated at least temporarily to the pressure in the brake of an unstable rear wheel, it is provided that, upon initiating a pressure decrease in the brake of an unstable rear wheel, the pressure in the brake of the stable rear wheel is kept constant for a predetermined period of time (.DELTA.t) and then decreased until the pressure in the brake of the unstable wheel is either kept constant or increased. This guarantees shorter stopping distances and at the same time provides a smaller difference in the braking torques at the rear axle, at good stability of the motor vehicle.

Abstract: For measuring the rotational speed of a wheel in an antilocking protected vehicle brake system a rotational speed sensor is provided in which in accordance with the rotational speed of the wheel signals are electromagnetically induced which have an amplitude and frequency which increase regularly with the rotational speed. When due to error sources the amplitude of the induced signal does not increase with the frequency of the signal a rotational speed measured value is determined by means of the measured amplitude, i.e. not on the basis of the measured frequency. To avoid erroneous measuring signals it may likewise be provided that when the amplitude of the signal does not increase with its frequency the last measured value of the frequency of the induced signal at which the amplitude still increased with the frequency is used to determine the speed of rotation.

Abstract: For measuring the rotational speed of a wheel is an antilocking protected vehicle brake system a rotational speed sensor is provided in which in accordance with the rotational speed of the wheel signals are electromagnetically induced which have an amplitude and frequency which increase regularly with the rotational speed. When due to error sources the amplitude of the induced signal does not increase with the frequency of the signal a rotational speed measured value is determined by means of the measured amplitude, i.e. not on the basis of the measured frequency. To avoid erroneous measuring signals it may likewise be provided that when the amplitude of the signal does not increase with its frequency the last measured value of the frequency of the induced signal at which the amplitude still increased with the frequency is used to determine the speed of rotation.

Abstract: A method of controlling the brake pressure in an antilock vehicle brake system in which rotational velocities of the vehicle wheels are measured and the brake pressure is modulated in dependence upon the retardation and the slip of a wheel on exceeding threshold values provides that for each braked wheel the difference between the vehicle reference velocity and a wheel reference velocity is determined for adjusting the length of the pressure maintaining or pressure diminishing phase in dependence upon the difference.

Abstract: A method of controlling the brake pressure in an anti-lock vehicle braking system provides for determining the deviation of a control magnitude, such as the slip or retardation of a wheel, from a given rated value Sw in the course of a control cycle. A threshold value which is decisive for the pressure decrease at a wheel subject to the risk of becoming locked is changed for the next successive control cycle in response to the amount of the deviation of the control magnitude from the rated value.

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: In an anti-lock vehicle braking system the brake pressure acting at the controlled wheel is controlled in such a manner that the threshold value with respect to the rotational retardation of the wheel at the beginning of a lowering or raising of pressure is increased briefly, during a control cycle, by a constant amount (S.sub.H -S.sub.G) with respect to a threshold base value (S.sub.G) in order to avoid any undesired control operations caused especially by axle vibrations, pot holes, and the like. The threshold value is then decreased in response to the period of time of the pressure reduction in the preceding control cycle. The decreasing of the threshold value is carried on to values S.sub.T below the threshold base value and maintained for a given time interval (t.sub.x -t.sub.y).

Abstract: An anti-locking brake system is described in which pressure drops produced in the event of rapidly succeeding wheel retardations and wheel accelerations are restrained. This is achieved by a summing circuit having a sum to which a numerical value is added; the sum is reduced according to a given function. The sum value present in each case is a measure of how the pressure reduction is to be restrained, for example, by raising thresholds.

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: An anti-locking brake control system for a motor vehicle comprises wheel speed sensors for determining the speeds of the individual vehicle wheels, an evaluation circuit which receives the wheels speed signals and generates brake pressure control signals, and a brake pressure control device responsive to the brake pressure control signals for controlling the brake pressure applied to the wheels. The evaluation (processing) circuit includes a brake pressure control unit which operates in such a manner that, after brake pressure decays, the brake pressure is first increased in a timed build-up with reference to the brake pressure build-up in a preceding control cycle, and thereafter the brake pressure is further increased by a sequence of pulses until an instability is again detected.

Abstract: In a method of controlling the brake pressure in an anti-lock vehicle brake system (ABS system), wherein the rotational behavior of a braked wheel is measured and the brake pressure is lowered in response to the slip and/or rotational retardation of the wheel if threshold values are exceeded, and is subsequently raised again and then kept constant during a phase of steady pressure, it is provided that the duration (t1H, t2H . . . t5H) of the pressure stability phase is adjusted in response to a comparison of the pressure reduction periods (t1DOWN, t2DOWN . . . ) and/or the pressure build-up periods (t1UP, t2UP . . . ) of the instantaneous control cycle (1,2 . . . 5) with those of at least one preceding control cycle in order to obtain shorter stopping distances.

Abstract: To provide an unambiguously representative signal responsive to the speed of a vehicle wheel, an inductive pick-up (1a. . . . 1n) is coupled to a suitable star wheel or the like of each one of the wheels, the pick-ups then providing their signals to amplifiers (3a. . . . . 3n) having hysteresis characteristics. At low speeds, an offset signal is superimposed on the voltage from the inductive pick-ups so that the amplifiers respond and provide output signals only at higher amplitudes of the pick-up signals, thereby eliminating inaccuracies or disturbances occurring in the sensor which might simulate changes in speed of the respective wheel.

Abstract: An anti-skid brake system has a first brake circuit (I) terminating at two wheel brakes and connected to a dual-circuit master cylinder, a brake pressure modulation valve assembly and a recirculating pump. In an anti-skid situation, in order to reduce brake pressure, fluid is withdrawn from the two wheel brakes by the brake pressure modulation valve assembly and then returned to the master cylinder by the recirculating pump. Associated with a second brake circuit (I), which is likewise connected to the master cylinder and which terminates at two other wheel brakes, is a floating piston assembly connected to the first brake circuit (I). In an anti-skid situation, a pressure reduction, which is performed in the first brake circuit (I) by the brake pressure modulation valve assembly brings about a pressure reduction in the second brake circuit (II), via the floating piston assembly.

Abstract: To extend the range of automatic control of a brake anti-lock system, wheel speeds (V.sub.R1 -V.sub.R4) are processed and changed into control signals (12, 15) controlling braking effort of the vehicle. A first predetermined vehicle reference speed (V.sub.REF) is provided, and compared with a computed or actual vehicle speed. If the computed or actual vehicle speed drops below the first reference level (V.sub.REF1), a transfer switch (25) changes over control of the braking pressure control unit (22) from the standard control unit (23) to an auxiliary or additional branch (26) which initially maintains braking pressure, but drops braking pressure if the wheel speed of an individual wheel drops below a minimum level (V.sub.min) and the actual vehicle speed is above a second reference level (V.sub.REF2), which second reference level is below the first reference level (V.sub.REF1). The second reference level (V.sub.REF2) corresponds to a speed in excess of the minimum (V.sub.min).