Abstract: A brake control system is described that maximizes the braking efficiency of an under-damped actuator, such as a motor-driven linear screw. When an incipient lock condition is detected, the system determines the optimal brake pressure, relieves brake pressure and measures the duration of the pressure release. When the wheel is approaching recovery, but has not yet substantially recovered, the system holds brake pressure constant at a value calculated to represent the amount of pressure remaining at the wheel brake. This calculated hold value is based upon the measured optimal pressure and the measured release duration, and allows the wheel to continue to reaccelerate towards recovery while preventing unnecessary pressure relief. Once the wheel recovers, the system reapplies brake pressure to a substantial fraction of the optimal pressure without over-exciting the actuator and over-shooting the desired pressure.

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: The brake system includes a brake pressure generator with a master cylinder connected to wheel brake cylinders through master brake conduits; auxiliary pressure pumps having pump outlets in communication with the master brake conduits and pump inputs in communication with a pressure fluid reservoir through inlet conduits; wheel sensors and electronic circuits for determining the wheel rotating pattern and for generating electrical brake pressure control signals capable of controlling pressure fluid inlet and outlet valves disposed in the conduit system for slip control. The traction slip control system insures, with little effort involved, assembling and disassembling capabilities, and, in disassembled condition, complying with the control principle for a driven front axle and, in assembled condition, complying with the traction slip control mode for a driven rear axle in all speed ranges.

Abstract: A brake control system is described that maximizes vehicle braking efficiency by maximizing the amount of time spent cycling pressure at or near the optimal pressure for the road surface. Upon detecting an incipient wheel lock condition, the system measures the optimal pressure for the road surface and relieves pressure. Once wheel recovery is sensed, the system reapplies pressure to a significant fraction of the optimal pressure and increases pressure gradually from that point. If a change to a higher coefficient surface occurs while the system is modulating brake pressure, the system detects that surface transition and rapidly increases brake pressure to quickly arrive at the new optimal pressure.

Abstract: A braking system of a motor vehicle including an accumulator, being coupled to a to motor-driven pump, for accumulating a hydraulic pressure which is supplied to a braking device to brake a wheel of the motor vehicle and a control valve provided between the accumulator and the braking device for regulating the hydraulic pressure to be applied from the accumulator to the braking device. Also included in the braking system is a control unit for controlling the control valve in accordance with the condition of the wheel. The control unit controls the motor-driven pump on the basis of the control time of the control valve.

Abstract: A testing device tests the brake fluid pressure circuit in an antilock control system for a motor vehicle. The testing device has a pressure switch provided in the line between a pump and a pressure accumulator in the brake fluid pressure circuit and a pressure switch detection adapted to give ON signals after the pressure indication of the pressure switch has risen above a predetermined point and give OFF signals after it has decreased below a predetermined point. If the signals fail to change from ON to OFF within a given time after issuing a command to release the pressure in the accumulator and if they fail to change from OFF to ON within a given time after issuing a command to pressurize the accumulator, the circuit is judged to be in an abnormal state.

Abstract: An electrically-controlled motor vehicle brake system, which responds to fluid pressure supplied from a common source. The system includes an electronic control system to process information and issue brake commands. A brake cylinder, to apply and release brake pressure on each respective wheel brake, receives pressure from at least one solenoid valve, connected to receive pressure from the source. The pressure is communicated to the brake cylinder of each respective wheel brake upon receipt of a control signal from the control system. A brake power selector includes both a pedal-operated brake valve, connected on an input side to receive pressure from the source, and connected on an output side to a ventilation portion of the solenoid valve for modulating the brake pressure, and an electrical frequency selector is connected to provide an input signal to the electronic control system upon actuation by an operator of such vehicle during a brake application.

Abstract: A brake control system for effectively properly performing a braking hydraulic pressure distribution between a front wheel and a rear wheel or a left wheel and a right wheel of a motor vehicle including a master cylinder for generating a hydraulic pressure in response to depression of a brake pedal thereof and applying the hydraulic pressure through first and second braking passages to first and second wheel braking cylinders. This brake control system has first and second pressure control devices respectively coupled to a braking pressure source for allowing the output hydraulic pressures to be regulated independently of each other under control of a control unit. The output of the first pressure control device is coupled through the first braking passage to the first wheel braking cylinder and the output of the second pressure control device is coupled through the second braking passage to the second wheel braking cylinder.

Abstract: A control valve for an anti-lock brake system includes a one-piece valve body having an inlet opening in one end and an outlet opening in an opposite end. The valve body is provided with four other openings extending into the body and defining separate associated chambers for respectively receiving an isolation valve assembly, a pressure differential switch assembly, a dump valve assembly and an accumulator assembly. The inlet, outlet, and the four internal chambers are connected by appropriate internal passageways. The control valve is used to selectively hold, dump, or reapply brake fluid pressure to selected wheel brakes to prevent lock-up of the associated wheels.

Abstract: An anti-lock hydraulic brake system which includes a brake pressure generator composed of a master cylinder, a brake power booster inserted upstream thereof and a pressure modulator interposed between the master cylinder and the brake power booster. A resetting unit is formed by supplementing the pressure modulator with a valve assembly which connects a resetting chamber of the pressure modulator to either a pressure-compensating reservoir or an auxiliary-pressure source. The braking pressure in the wheel brakes is controlled, according to a time-multiplex method, by wheel valves inserted into the pressure-fluid conduits and by the pressure modulator. In order to check the operability of the brake and of the anti-lock control system, a pressure switch is connected to the pressure modulator and a test circuit is provided which, at predetermined points of time, initiates a test cycle, actuates the valves and compares the valves' operation with the reaction of the pressure switch.

Abstract: A dual-circuit hydraulic anti-lock braking system for an automotive vehicle having a first and a second group of wheels, including (a) a dual-circuit hydraulic braking device including a first and a second brake circuit which are independent of each other, (b) a wheel rotating condition detecting device; (c) a vehicle running condition detecting device; (d) a regulating device for regulating each of a first and second braking pressures transmitted by the first and second brake circuits, respectively, by decreasing or increasing the braking pressure for a duration of time, when the detected rotating condition of at least one wheel of each of the first and second wheel groups is brought into a predetermined relationship with the detected running condition of the vehicle so as to apply the regulated pressure to a brake cylinder associated with the wheel whose detected rotating condition is brought into the predetermined relationship with the detected running condition of the vehicle.

Abstract: An anti lock braking system for a vehicle includes transducers acoustically coupled to a non-rotating member of the wheel assembly and adapted to provide an electrical output signal dependent upon the degree of acoustic emission activity in the non-rotating member. A detector is adpated to analyze when the electrical output signal which corresponds to the= acoustic emission activity in the non-rotating member falls to zero when brake pads are in frictional contact with the confronting surface of the wheel. The detector is adpted to send a feedback signal to a control device which controls the pressure applied to the wheel by the brake pads. Preferably the detector measures the instantaneous change of electrical output signal as a funtcion of the pressure applied by the brake pad.

Abstract: A brake system with anti-lock control and traction slip control is disclosed. The system includes a braking pressure generator composed of a master cylinder and a brake power booster. Also provided is an auxiliary-pressure supply system which generates an auxiliary pressure proportional to the pedal force for anti-lock control and generates an uncontrolled predetermined auxiliary pressure for traction slip control. The wheel brakes of the front wheels are connected to the master cylinder. By way of valve assemblies, the auxiliary-pressure supply system is connected to the wheel brakes of the front wheels in the control phases. The rear-wheel brake circuit is designed as a dynamic circuit and is fed directly by the auxiliary-pressure supply system.

Abstract: Disclosed is an anti-skid control system incorporated in the hydraulic pressure braking apparatus of a motor vehicle including a wheel braking cylinder responsive to a hydraulic pressure developed by a master cylinder for braking a wheel of the vehicle. The anti-skid control system comprises a hydraulic pressure supplying device and a directional control valve provided between the wheel braking cylinder and the hydraulic pressure supplying device. The directional control valve is actuated to shut off the communication therebetween and the actuation thereof is controlled in accordance with a duty cycle, which is in turn updated in accordance with the difference between a wheel speed and a target wheel speed so that the slip ratio of the wheel becomes equal to a target slip ratio.

Abstract: The present invention concerns a vehicle anti-lock brake control system which does not require the use of an auxiliary hydraulic pump and, in the preferred embodiment, is adapted to control only the rear brakes of a four-wheel vehicle. The control system includes a normally open solenoid actuated isolation valve connected between the master cylinder and the rear wheel brakes, and a normally closed solenoid actuated dump valve connected between the rear wheel brakes and a fluid accumulator. A computer control is connected to monitor the rear wheel speed and deceleration and, during breaking of the vehicle, functions to control the application of hydraulic pressure to the rear brakes via the isolation and dump valves in order to prevent lock-up of the brakes. In the event excessive rear wheel deceleration is detected during a vehicle stop, the computer control closes the isolation valve to hold pressure to the rear brakes at a relatively constant level.

Abstract: A brake control system is described that prevents a wheel lockup condition by identifying the brake pressure that produces the maximum possible braking effort during each brake pressure application period and applying a predetermined fraction of the identified pressure after an incipient wheel lockup condition is sensed. The predetermined fraction provides for adaptive adjustment of the brake pressure if the identified brake pressure is in error until a pressure is applied that produces substantially the maximum possible braking effort.

Abstract: A system for guarding against the leakage of fluid from a hydraulic system, particularly an aircraft braking system, which employs a flow control valve under the control of an electronic processor. The electronic processor integrates with respect to time a function of the input signal to the flow control valve and the pressure of the output of fluid, compares the value of the integrated function with a predetermined value, and effects closure of the control valve if the comparison indicates a substantial fluid loss.

Abstract: A vehicle braking system having a wheel lock control arrangement with isolation valves for each wheel brake and either three or four solenoid and brake control valves for the system. In one arrangement, each wheel brake and isolation valve has its own solenoid and control valve. In other arrangements two front wheel brakes have separate solenoid controlled operating valves and the two rear wheel brakes have a single solenoid controlling operating valve controlling both isolation valves. Traction control is incorporated into the system so that a wheel brake required braking for traction control purposes may be applied by pump pressure without the vehicle brakes themselves having to be applied through service braking.

Abstract: In order to reapply the fluid operating pressure to the braking members of the wheels after an anti-locking operation has been carried out, a pumping device is provided which are driven by the subatmospheric pressure (vacuum) existing in the inlet manifold of the engine. The application of the braking pressure is controlled by a valve which receives an opening command signal consisting of a train of pulses from a control device. At least one vacuum sensor is provided which generates a monitoring signal indicative of the level of vacuum present in the inlet manifold. The control device causes opening of the valve with a command signal whose average is inversely proportional to the level of the monitoring signal generated by the vacuum sensor.

Abstract: A brake control system is described that prevents a wheel lockup condition by identifying the brake pressure that produces the maximum possible braking effort during each brake pressure application period and applying a predetermined fraction of the identified pressure after an incipient wheel lockup condition is sensed. One criteria for sensing an incipient wheel lockup condition is the decrease in the braking effort from the maximum possible braking effort by a predetermined amount as wheel slip increases from a critical slip value.

Abstract: A wheel lock control system is described for a wheel braking system that includes a motor driven actuator for applying controlled hydraulic pressure to the wheel brake. The component of the motor current representing the brake pressure is determined and the motor current corresponding to the brake pressure producing the maximum possible braking effort during each brake pressure application is identified and reapplied to the motor after an incipient wheel lockup condition is sensed.

Abstract: A braking system having a pressure modulator which, during normal braking operation, delivers a fluid pressure which is a predetermined multiple of a fluid pressure generated by the master cylinder to a wheel cylinder. The pressure modulator has a solenoid actuator which is energized during braking force proportioning and anti-skid operations to reduce the delivery pressure. In a preferred embodiment, the pressure modulator further includes another solenoid actuator for increasing the delivery pressure during braking force proportioning operation and for delivering fluid pressure during traction control operation.

Abstract: A wheel lock control system is described for a wheel braking system in which the brake pressure producing the critical slip value and therefore the peak braking effort is precisely determined. The brake pressure that is reapplied following an incipient wheel lockup condition is determined as a function of (A) the brake pressure and wheel deceleration corresponding in time to the peak calculated tire torque tending to accelerate the wheel during braking prior to the detection of an incipient wheel lockup condition and (B) the brake pressure and wheel acceleration corresponding in time to the peak calculated tire torque tending to accelerate the wheel during wheel speed recovery following an incipient wheel lockup condition. By using these parameters, the precise brake pressure for establishing the critical wheel slip is determined so that the maximum braking effort may be established following a detected incipient lockup condition.

Abstract: An apparatus for monitoring the pressure of an auxiliary energy source (10, 11, 12) of a slip-controlled brake system for motor vehicles comprises at least two switches responding when falling below a pressure limit value(p.sub.1), releasing warning signals and influencing the function of the brake slip control. Through logical operation of the switch functions, failure of a switch (ws1, ws2) will be detected and an error signal derivable therefrom resulting in the partial shut-down or cut-off of the control. The monitoring circuit responds to two different pressure limit values (p.sub.o, p.sub.u). The brake system is partially shut down or cut off by measuring the interval (.DELTA.T) between the response to the upper and lower pressure limit threshold (p.sub.o and p.sub.u, respectively), locking and then switching on the master valves (21, 22), detecting the reaction on turning on again the master valves etc., and by logical operation of the signals.

Abstract: A hydraulic brake-power booster unit is provided for a vehicle having a dual-circuit brake system and an antilock system operating according to the drain principle. When the brake system is intact, the booster unit provides dynamic pressure to one of the two brake circuits and static pressure admission to the other. The pressure to the static brake circuit takes place by the separate-power-assisted shifting of an emergency piston. On one side, the emergency piston delimits an output pressure space to which the brake circuit that can be statically acted upon by pressure is connected. This brake circuit also remains operable in the case of a breakdown of the hydraulic power source only by the operation of the pedal and the resulting possible shifting of the emergency piston. A path transducer generates an electrical signal proportional to the position of the emergency piston.

Abstract: A method for ascertaining an optimal slip value .lambda. at at least one wheel of a vehicle, in order to be able to regulate the braking force optimally. To this end, at least the wheel speed is measured, and the vehicle speed is ascertained. By varying the braking pressure and the slip during driving, signal combinations for the wheel speed, the vehicle speed, the braking pressure and the tire/road contact force are ascertained and inserted into a given function V.sub.R (K+1). For the resultant equation system, the coefficients .alpha..sub.n can then be ascertained from which the coefficients a.sub.n of a general description of the .mu. slip curve can be ascertained. With these coefficients a.sub.n, the .mu. slip curve and its maximum, from which the optimal slip .lambda. can then be ascertained, are then clearly defined.

Abstract: A hydraulic brake booster including, master brake cylinder pistons disposed in telescoping fashion in a short housing structure, and a locking piston for the brake pedal actuation is disposed parallel to the master brake cylinder in axial alignment with the travel simulator and a brake valve. A further parallel disposition of an adjusting piston is acted upon by reservoir pressure and in which the master brake cylinder pistons are supported in a slidably displaceable manner.

Abstract: An overload protection and/or warning arragement for a vehicle brake which is activated by brake pressure so that overload protection and warning indication occurs essentially without any time-delay.In one embodiment of the invention, it is proposed to compare, by means of a comparison apparatus, a design brake pressure P(design) determined on the basis of a regulated variable imparted to an activation apparatus of the vehicle brake and of operating data of the vehicle and/or of the design data of the brakes and of the brake application apparatus with the actual brake pressure P(actual), and to initiate a warning signal if P(actual) differs by a specified amount from P(design).In another embodiment of the invention, it is proposed that the warning signal be initiated if the actual brake pressure produced by the existing brake pressure differs by a specified amount from a design brake force which is determined from the brake pressure and the design data of the brake and the brake-actuating apparatus.

Abstract: A control circuit for adapting slip control of an anti-skid brake system of an automotive vehicle comprising a friction coefficient identification circuit (31, 31'). Upon the instabilization of a wheel the braking pressure control signals controlling the slip by actuating solenoid valves (36-41) are varied by the output signal of the circuit (31, 31') as a function of the momentary deceleration (v.sub.R) of the fastest wheel and/or on the momentary pressure in the hydraulic brake circuits (52, 53, 54) and thus are adapted to the momentary friction coefficient, which in particular depends on the road condition. In one instance, the gradient of the vehicular reference velocity is varied in dependence on the friction coefficient.

Abstract: A brake control system is described that prevents a wheel lockup condition by identifying the brake pressure that produces the maximum possible braking effort during each brake pressure application period and applying the identified pressure after an incipient wheel lockup condition is sensed. Constants in an expression estimating the braking effort are adaptively adjusted to compensate for changes in system parameters over time.

Abstract: In accordance with the present invention, a normally open isolation valve is connected between a master cylinder and the selected wheel brakes, and a normally closed dump valve is connected between the selected wheel brakes and a fluid accumulator. A computer control module is connected to operate the isolation valve and the dump valve. In operation, when a slip condition of the controlled wheels is detected, the computer control module closes the isolation valve to hold fluid pressure to the controlled brakes at a relatively constant level. If the deceleration of the controlled wheels exceeds a predetermined amount, the computer control module will selectively open the dump valve to enable fluid to flow into the accumulator, thereby reducing the deceleration of the associated wheels.

Abstract: The present invention concerns a control valve for use in a vehicle anit-lock braking systm adapted to control the application of pressurized brake fluid to at least one selected vehicle brake. The valve includes an outer housing having an inlet coupled to receive pressurized brake fluid from the vehicle master cylinder and an outlet coupled to supply pressurized brake fluid to the selected vehicle brakes. A passageway is formed in the housing for connecting the inlet to the outlet. A normally open isolation valve is located in the passageway and is utilized to control the flow of fluid through the passageway between the inlet and the outlet. When an incipient wheel lock condition is detected, the isolation valve can be closed to prevent a further increase in pressure to the controlled brakes and to hold the pressure supplied to the controlled brakes at a relatively constant level.

Abstract: A brake control system is described that prevents a wheel lockup condition by identifying the brake pressure that produces the maximum possible braking effort during each brake pressure application period and applying a predetermined fraction of the identified pressure after an incipient wheel lockup condition is sensed. The predetermined fraction provides for adaptive adjustment of the brake pressure if the identified brake pressure is in error until a pressure is applied that produces substantially the maximum possible braking effort.

Abstract: A brake system provided for automotive vehicles comprises a braking pressure generator (3) and a braking pressure modulator (4) which is arranged in the pressure medium conduit leading to the rear wheel brakes (16, 17) and which allows to vary the apportioning of the braking pressure to the wheel brakes of the front and the rear axle to achieve approximation to an ideal brake force distribution in dependence on the instantaneous axle load. The braking pressure modulator (4) contains valve assemblies (5) serving to supply braking pressure alternately to the wheel brakes (16, 17) of the right and the left rear wheel in such a manner that one of the two rear wheels (HR or HL) furnishes the predominant portion of the brake force allotted to the rear axle. The pressure delivery alternates to connect to the other rear wheel on each braking operation or on each brake actuation or according to predetermined time criteria.

Abstract: To maintain stability of operation of a vehicle entering a curve, for example with excessive speed upon entering the curve, and application of the vehicle brakes by the operator, the braking effort (P.sub.HA) applied to the rear wheels or rear axle of the vehicle is controlled to be at a low and constant level, substantially below the braking effort (P.sub.VL, P.sub.VR) applied to the front wheels of the vehicle, and for a limited period of time (t), which may be a predetermined time duration, under control of a timing element (4), or which may depend on counted braking cycling events, of braking effort applied to the front wheels, for example under control of an anti-brake locking or blocking system (ABS). For example, a counter (8) may count two cycles of operation of the ABS and then release the low, constant braking effort phase applied to the rear wheels of the vehicle. Stability of operation of the vehicle, in the curve, is thus maintained.

Abstract: A vehicle brake and wheel anti-lock control system in which an electronically controlled actuator normally provides brake pressure for the vehicle wheel brakes and also acts as a modulator to vary the brake actuating pressures for wheel anti-lock control. The actuator is so arranged that a master cylinder may be used to provide actuating pressure to the wheel brakes, the pressure passing through the actuator pressurizing chamber, if for any reason the actuator does not perform as needed to provide brake actuating pressure to stop the vehicle.

Abstract: A wheel slip controlling system according to the present invention comprises braking actuator operable by a driver of a car for braking rotation of wheels at least including driving wheels, slip detector for detecting a slipping condition of the wheels to output a slip signal indicative of the slipping condition, anti skid controller for receiving the slip signal and for controlling, in response to the slip signal received, the pressure to be imparted from the braking actuator with a self-contained pressure source to control braking slips of said wheels at least including the driving wheels and traction controller responsive to the slip signal during acceleration of the car for controlling the driving wheels with the self-contained pressure source for control acceleration slips at least of the driving wheels.

Abstract: A wheel anti-blocking control system (ABS), in which, subsequent to a brake pressure drop, the first brake pressure rise pulse .DELTA.P.sub.2 is controlled, in dependence on the preceding brake pressure drop (.DELTA.P.sub.1) and on a quotient defined by the relationship: ##EQU1## in which +.omega..sub.m and -.omega..sub.m are representative of maximum angular acceleration/deceleration of the respective wheel being controlled and .alpha. is a factor somewhat less than unity, and which may vary in dependence on the direction of movement of the vehicle, for example whether the vehicle is moving in a straight path or is moving along a curve. If moving along a curve, so that angular acceleration is involved, the factor .alpha. is reduced.

Abstract: A brake force regulating system for motor vehicles has a brake pedal, a brake regulator and transducers for ascertaining driving-situation variables which act upon the brake regulator. A desired value (Z.sub.s) of the deceleration (Z) of the motor vehicle is prespecified by the brake pedal; the actual value is ascertained; and the brake regulator is regulated by the deviation between the desired value and the actual value. Furthermore a regulation is provided in accordance with the slip between the road surface and the wheel.

Abstract: To prevent oscillation of a wheel being intermittently braked in an anti-slip or anti wheel block system, an increase of braking pressure, after a prior decrease, is controlled to occur during a first time interval which is short with respect to an oscillation period of the wheel if subjected to brake pressure pulses, so that the braking pressure increase will be small or short, e.g. about 3 milliseconds, comparable to stepped pressure increases after an initial wheel deceleration and permitted re-acceleration, the pressure then being maintained at an even level for an interval (T.sub.3) which, likewise, is short with respect to the intervals (T.sub.0, T.sub.4) between stepped increases. The respective time intervals can be controlled by individual, special pulse generators, or by suitable programming of microprocessor elements.

Abstract: A control unit (14, 60) controls the braking pressure (P) at the brakes or the wheels, at both right and left sides of an axle, in accordance with "select-low" and/or "select-high" mode. The system is improved by associating a pressure sensor responsive to braking pressure in at least one of the front wheels. The control unit (14, 60) is so arranged that, upon sensing a tendency to skid or block at the rear wheels (FIG. 3: t.sub.3), the pressure at the rear wheels is controlled to a lower level than that at which tendency to block had been sensed, and then a constant pressure maintenance phase is commanded at a predetermined pressure (P.sub.oHA) for an extended period of time (to t.sub.8), for example under control of a timing element (FIG. 2: 19) or until the pressure sensor determines that the braking pressure (P.sub.