Abstract: There is provided a method of energising a solenoid of a valve assembly, comprising the steps of applying a positive over boost voltage to the solenoid to actuate a moveable plunger to open or close a flow path through the valve assembly, and then applying a negative braking voltage to brake the movement of the plunger during movement of the moveable plunger. There is also provided a method of energising a solenoid of a valve assembly, the method comprising the steps of receiving a demand signal to actuate the valve, applying a wait time after receipt of the demand signal, applying a positive over boost voltage across the solenoid to actuate a moveable plunger to open or close a flow path through the valve assembly, monitoring the solenoid closure time, and adjusting one or more input variables in order to control the solenoid closure time.

Abstract: A pedal travel simulator for a hydraulic vehicle power braking system with a cup-shaped cylinder cover in which a piston spring is accommodated, which is held by an orifice disk as a stop for a piston of the pedal travel simulator in the cylinder cover. Recesses are provided in an outer edge of the orifice disk, through which the piston is able to displace brake fluid on its rear side out of a cylinder of the pedal travel simulator through a circumferential groove into a return.

Abstract: A valve module is provided for enabling a vehicle to control an autonomous event of the vehicle. The valve module comprises a relay valve, a first solenoid valve, and a second solenoid valve. A first control pressure can be delivered through the first solenoid valve and applied to a control port of the relay valve. In one embodiment, a second control pressure can be delivered through the second solenoid valve and combined with the first control pressure. The combined first and second control pressures are applied to the control port of the relay valve. In another embodiment, a second control pressure can be delivered through the second solenoid valve only when no first control pressure is delivered through the first solenoid valve.

Abstract: Embodiments relate to a speed sensor device including a sensor element to provide a sensor signal, a status module to provide status information of the speed sensor device; and a processing module to generate an output signal. The output signal is derived from the sensor signal, if the status information is indicative of a non-critical state of the speed sensor device, and the output signal is a safety message signal having signal edges such that time intervals between subsequent congeneric signal edges are equal to or shorter than a preselected threshold, if the status in-formation is indicative of a critical state of the speed sensor device. An Electronic Control Unit (ECU) includes an interface for receiving a signal having signal edges from a speed sensor device and a processing unit to analyze time intervals between subsequent congeneric signal edges.

Abstract: A device for operating a motor vehicle includes a drive unit configured to drive the motor vehicle in order to make available adjustable starting assistance. A sensing unit is configured to sense a brake pressure of a brake arrangement of the motor vehicle, where the brake pressure is adjustable using a brake pedal. A control unit is configured to set a degree of starting assistance that is made available when the brake pressure, which is sensed during a stationary state of the motor vehicle, exceeds a predefined threshold value.

Abstract: A vehicular brake fluid pressure control apparatus includes: normally open and normally closed electromagnetic valves disposed to correspond to plural wheel brakes; and a control unit which controls fluid pressures transmitted to the wheel brakes by controlling drive currents applied to the electromagnetic valves according to plural different fluid pressure control modes. The control unit controls the normally closed electromagnetic valves while switching, according to which of the fluid pressure control modes is effective, between a responsivity priority control in which drive currents applied to the normally closed electromagnetic valves are increased to a target current value instantaneously at a first slope, a silence priority control in which the drive currents are increased at a second slope gentler than the first slope, and an intermediate control in which the drive currents are increased at a third slope gentler than the first slope and steeper than the second slope.

Abstract: A hydraulic brake system includes: a hydraulic pressure source provided for a vehicle, and including a hydraulic-pressure generating device and a reservoir; a plurality of hydraulic brakes provided for respective wheels of the vehicle, and configured to restrain rotations of the respective wheels; and a control valve device including at least one hydraulic-pressure control valve group disposed between the hydraulic-pressure generating device and at least one of brake cylinders of the hydraulic brakes and/or between the reservoir and the at least one of the brake cylinders. Each of the at least one hydraulic-pressure control valve group includes (a) at least one ON/OFF control valve and (b) at least one linear control valve that are disposed in parallel with each other.

Abstract: A brake control method for a hydraulic brake device equipped with an actuator that automatically regulates braking liquid pressure in a wheel cylinder of a vehicle without driver intervention. The method includes: (a) calculating a time period in which holding or decreasing brake hydraulic pressure is continuously performed to the wheel cylinder; and (b) controlling the actuator such that, an increasing pressure and decreasing pressure to the wheel cylinder after the calculated time period has reached a predetermined time, the amount of the pressure increase and the amount of the pressure decrease are the same.

Abstract: An anti-skid braking system for an aircraft having a brake pedal in communication with a master cylinder and fluid reservoir, and a brake caliber engaged with a wheel. The system includes a three way hydraulic valve controlled by a solenoid wherein the hydraulic valve is in fluid communication with and between the master cylinder and fluid reservoir and the brake caliper. A double acting spring loaded accumulator has an accumulator piston wherein the accumulator is in fluid communication with and between the three way hydraulic valve and the brake caliper. A hydraulic pump is in fluid communication with and between the three way hydraulic valve and the brake caliper.

Abstract: A vehicle brake fluid pressure control apparatus includes: a normally open electromagnetic valve which adjusts a differential pressure between an upstream side and a downstream side; and a control unit including a memory part which stores a valve closing map which shows a relationship between the differential pressure between the upstream side and the downstream side of the pressure regulator valve and an output current value for closing the pressure regulator valve and a valve opening map which shows a relationship between the differential pressure and an output current value for opening the pressure regulator valve, wherein when attempting to reduce a fluid pressures, the control unit executes a current value switching control which controls a current flowing to the pressure regulator valve by selecting alternately an output current value of the valve opening map and an output current value of the valve closing map.

Abstract: For a vehicle equipped with a self-braking system (for example, ASR, ESP, FDR, EBS), a service brake, a parking brake, and at least one associated pressure sensor for detecting at least one pressure in the vehicle brake circuit, the brake circuit comprising a compressed-air circuit, a process to prevent the vehicle from rolling away includes determining whether a pressure in the compressed-air circuit from which the parking brake is fed is below a release threshold, and operating the service brake if the pressure in the compressed-air circuit is below the release threshold.

Abstract: Systems and methods disclosed herein may be useful for braking systems for use in, for example, an aircraft. A method is disclosed comprising determining, at a brake controller, an aircraft reference speed for an aircraft having a first wheel and a second wheel, identifying, at the brake controller, a state comprising the first wheel having a different rotational velocity than the second wheel, wherein the difference in rotational velocity sums to about zero, calculating, at the brake controller, a compensation factor for at least one of the first wheel and the second wheel, and adjusting, at the brake controller, a locked wheel trigger velocity in accordance with the compensation factor.

Abstract: An anti-skid control apparatus comprises an anti-skid control means for controlling a pressure reducing valve and a pressure increasing valve, each of which operated for a target wheel when an anti-skid condition is established for the target wheel, the pressure increasing valve controlled in order to linearly change a pressure difference, an estimating means for estimating an occurrence of a factor by which the brake hydraulic pressure is fluctuated at the conduit connecting the master cylinder to the pressure increasing valve for the target wheel while the pressure increasing valve is controlled for the target wheel, and an output means for generating an output for maintaining the pressure difference during a predetermining time period in which the pressure increasing valve is controlled, when the occurrence of the factor is estimated.

Abstract: A vehicle brake fluid pressure control apparatus includes: a controller configured to control fluid pressures in wheel brakes to increase or reduce by controlling normally open electromagnetic valves and normally closed electromagnetic valves, wherein the controller perform: a pressure reducing in a pressure reducing cycle in which a basic pressure reducing control and a gradual pressure control are performed continuously in a case that the controller determines to execute a pressure reducing control with wheel speeds decreasing; a pressure reducing control in a basic pressure reducing amount in the basic pressure reducing control; and a temporary holding control for holding the fluid pressure and a fine pressure reducing control for executing a pressure reducing in an amount smaller than the basic pressure reducing amount in a case that the wheel speeds tend to decrease after the temporary holding control in the gradual pressure reducing control.

Abstract: A method of braking a vehicle which includes ground engaging wheels, and a braking system with ABS capability and including an operator actuated brake control, the ABS becoming operative in response to the operator actuating the brake control, and upon the braking system sensing the slippage or impending slippage of at least one of the ground wheels relative to the ground, to vary the braking force applied to the at least one of the wheels between, in alternative periods, an applied state in which the braking force is applied, and a released state in which the braking force is released, and characterised in that the method includes applying torque to assist acceleration of the wheel at least during periods in which the braking force is released by the ABS.

Abstract: A trailer sway intervention system. The trailer sway intervention system includes a trailer having a plurality of wheels, each wheel having a brake, and a vehicle towing the trailer. The vehicle includes a plurality of sensors configured to sense operating characteristics of the vehicle, and a controller. The controller receives the sensed operating characteristics from the sensors, determines an error based on a difference between an expected yaw rate and a sensed yaw rate, asymmetrically applies braking forces to one or more trailer wheels based on the difference, and symmetrically applies braking forces to the trailer wheels when the absolute value of the difference between the expected yaw rate and the sensed yaw rate is declining.

Abstract: Systems and methods for stabilizing a hybrid electric vehicle (“HEV”) towing a trailer. One system includes a regenerative braking system, a non-regenerative braking system, and a stabilization system. The stabilization system determines a direction of rotation and a speed of the HEV and compares the HEV's speed to a predetermined low speed threshold value and a predetermined high speed threshold value. The stabilization system instructs the regenerative braking system to brake at least one wheel when the speed is less than or equal to the predetermined low speed threshold value and instructs the regenerative braking system to brake at least one wheel opposite the direction of rotation and at least one of the regenerative braking system and the non-regenerative braking system to provide an extra stabilizing braking torque to at least one wheel opposite the direction of rotation when the speed is greater than the predetermined high speed threshold value.

Abstract: A system (10) and method for automatically controlling braking of a train (38). The method includes applying a first degree of braking to the train during a first period of time, and then applying a second degree of braking to the train during a second time period following the first time period so that the train is slowed in a manner effective to limit a peak deceleration rate experienced by the train. The system includes a sensor (36) providing a signal indicative of an operating condition of a locomotive of the train requiring braking of the train, a memory (22) storing a braking schedule, and a processor (18) comprising logic executable for accessing the braking schedule stored in the memory responsive to the signal to automatically control braking of the locomotive according to the schedule.

Abstract: In an active brake pads retraction system, the improvement is a metering check valve which limits the retraction. The metering check valve is interfaced with an anti-lock brake system (ABS), disposed in the hydraulic brake line between the brakes apply system of the ABS and a caliper member of the ABS located at each brake corner. Brake pads are retracted with respect to the brake rotor responsive to predetermined conditions of the motor vehicle in which braking is not required, wherein a retraction volume within the metering check valve limits the amount of brake pads retraction.

Abstract: A control system (11) for a vehicle (10) includes vehicle dynamics sensors (35-47) providing a vehicle dynamics signal. Tire monitoring system sensors (20) in each wheel generate tire signals including temperature, pressure and acceleration data. A controller (26) communicates with the tire monitoring system sensors (20) and at least one vehicle dynamics sensor, and generates a roadway surface condition estimation value as a function of the multi-axis acceleration data of the tire signals. The roadway surface condition estimation value is transmitted to a suspension control system (33) to adjust the vehicle suspension characteristics in response to the roadway surface condition estimation value.

Abstract: A brake control apparatus for a vehicle includes an actuator and a controller that controls the wheel cylinder pressure to a target hydraulic pressure by driving the actuator in response to a braking request. The controller sets a ceiling value for the rate at which the wheel cylinder pressure is changed in accordance with a temperature, and the wheel cylinder pressure is changed at a rate that is equal to or lower than the ceiling value.

Abstract: An active vibration insulator includes an electromagnetic actuator, a controller, and a bad-roads processor. The electromagnetic actuator generates vibrating forces depending on electric-current supplies. The controller carries out vibrating-forces generation control. In the vibrating-forces generation control, the electric-current supplies are made variable so as to actively inhibit vibrations generated by an on-vehicle vibration generating source of a vehicle from transmitting to a specific part of the vehicle based on cyclic pulsating signals output from the on-vehicle vibration generating source. Thus, the controller lets the electromagnetic actuator generate the vibrating forces. The bad-roads processor stops the vibrating-forces generation control effected by the controller when the vehicle travels on bad roads.

Abstract: A spring-actuated parking brake includes a spring brake actuator communicating with a fluid source via a supply line. In brake released condition, the actuator is pressurized via a supply valve; in engaged condition, the actuator communicates with a pressure sink via the supply valve and a pressure-relief line. During brake engagement, the supply valve and a shutoff valve between the supply valve and actuator are switched to flow-enabled position for pressure relief of the actuator placing it in communication with the pressure sink. For brake release, the supply valve is switched to the fluid source and the shutoff valve is switched to fluid-passing position communicating with the fluid source to pressurize the brake cylinder. After brake engagement, the shutoff valve is switched to shut-off position decoupling the actuator from the supply line; the supply valve is switched to flow-enabled position placing the supply line in communication with the pressure sink.

Abstract: A vehicle brake device A is provided with a master cylinder 10, a reservoir tank 12, solenoid valves 46 and 48 for adjustably draining brake oil from outlet ports 10a, 10b of the master cylinder 10 to the reservoir tank 12, a collision detection sensor 68 for detecting a collision of the vehicle, a fluid pressure meter 61 for detecting the master cylinder pressure, and an ECU 70. The ECU 70 detects the pushing-up of the brake pedal 11 based on the occurrence of a collision and the master cylinder pressure, and upon detection of the pushing-up, controls the solenoid valves 46 and 48 to adjust the draining of the brake oil so that the brake pedal 11 is withdrawn. Thus, a time point when the brake pedal 11 begins to be pushed up by the cause of the vehicle collision can be detected accurately and reliably, and the brake pedal 11 can be withdrawn accurately in dependence on the pushing-up.

Abstract: A method for controlling releasing force for a parking brake applies a releasing force based on vehicle speed. Vehicle speed may be divided into several speed ranges between 0 and 5 km/h, each speed range having a releasing force. After applying the calculated releasing force, if the brake has not been released, the method may apply a maximum force. The method may further not engage the brake if the vehicle speed exceeds a predetermined speed.

Abstract: A vehicular brake control apparatus includes a braked member that rotates together with a wheel, a braking member, an electric driving device that presses the braking member against the braked member to apply a braking torque to the wheel, when being supplied with electric current, an operational state detector that detects an operational state of the vehicle and provides a quantity of state representative of the operational state of the vehicle, a braking torque change request determiner that selectively determines that the braking torque is to be increased and that the braking torque is to be reduced, based on the quantity of state, and a current controller that controls supply of electrical current to the electric driving device so that the electric driving device is caused to drive in a predetermined direction if it is determined that the braking torque is to be increased, and so that the electric driving device does not drive in the predetermined direction if it is determined that the braking torque is t

Abstract: In a method of operating a brake assistant system which includes a first mode of operation in which the brake assistant system is not operated, a second mode of operation in which, after recognition of an emergency brake situation, a pressure build-up of wheel brakes is generated, and a third mode of operation which is provided for the transition from the second into the first mode of operation, wherein in the third mode of operation the wheel brake pressure (pWHEEL) is excessively elevated compared to the tandem master cylinder pressure (pTMC) in a controlled way, a particularly safe and user-friendly termination of the brake assistant system results from diminishing the amount of the excess elevation over the course of time.

Abstract: An anti-lock controller controls the brake fluid pressure of a wheel brake to a pressure decreasing mode where a normally-opened electromagnetic valve is closed while a normally-closed electromagnetic valve is opened, a holding mode where the normally-opened electromagnetic valve is closed and the normally-closed electromagnetic valve is closed, and a pressure increasing mode where the normally-opened electromagnetic valve is opened while the normally-closed electromagnetic valve is closed.

Abstract: The Smart Resolution Valve Pressure Control System allows any pressure control system using valve state pulsing to modify airflow at an optimum and consistent range of operation thereby enhancing control accuracy and increasing the useable cycle life of any valve combination used.

Abstract: Noise produced during a supplemental brake apply is reduced eliminated by reducing the quantity of additional brake fluid supplied to the pump during the apply. The prime valve is opened only at the initiation of the supplemental apply to supply a predetermined small quantity of brake fluid to the accumulator and pump inlet and is then closed for the remainder of the apply. The quantity of extra fluid supplied can be retained by the accumulator and does not need to by blown off back to the master cylinder. The apply valve of the non-regulated wheel brake is controlled to regulate pressure to the regulated wheel brake through the apply valve thereof, which is left open while the release valve of the regulated wheel brake is left closed. The release valve of the non-regulated wheel is controlled to maintain a lower pressure at the non-regulated wheel, preferably equal to the master cylinder pressure whenever possible, while permitting fluid flow back to the accumulator.

Abstract: A releasable brake pedal system 10 for a vehicle includes a pedal assembly 12 operatively engageable by the driver of the vehicle and a hydraulic actuator assembly 20 for generating pressurized hydraulic fluid for actuating one or more brakes 44A-44D. The pedal system 10 further includes a pressure release valve 30 or 30′ coupled in fluid communication with the pressurized hydraulic fluid. The pressure release valve 30 or 30′ is operative to reduce the amount of pressure applied to the brakes 44A-44D during a detected vehicle deceleration indicative of a collision event. The pressure release valve 30 is responsive to a deceleration sensor 40 according to one embodiment, and valve 30′ employs a deceleration sensitive inertial mass 76 according to another embodiment. Accordingly, the pedal system 10 reduces forces that may otherwise be transferred to the pedal assembly 12 during a collision.

Abstract: An anti-skid control system for an automotive vehicle includes a hydraulic modulator having electromagnetic solenoid valves for regulating a wheel-brake cylinder pressure at each of road wheels. A skid control unit prevents a wheel lock-up condition by controlling the wheel-brake cylinder pressure via on/off reaction of the solenoid valves in response to a pulse signal based on a wheel speed detected by a wheel speed sensor. The skid control unit has a data processing section that generates a desired wheel speed based on the wheel speed, calculates a desired brake-fluid pressure based on an integrated value of a wheel-speed deviation between the desired wheel speed and the wheel speed, sets a controlled ON pulse width based on the desired brake-fluid pressure, and outputting the pulse signal having the controlled pulse width to the solenoid valves after a lapse of a preset pulse width from a previous pulse signal output.

Abstract: An apparatus for determining a road-wheel vibration for an automotive vehicle comprises wheel-speed sensors for detecting wheel speeds of each of road wheels, and a control unit which is configured to be electrically connected to the wheel-speed sensors for processing a wheel-speed data signal detected from each of the wheel-speed sensors.

Abstract: A vehicular brake control method and apparatus having a controller that controls a pressure of a supplied operating fluid to the wheels. The vehicle brake control apparatus includes brakes that apply braking forces corresponding to the pressure of the operating fluid to the wheels. A pump is provided that force-feeds the operating fluid. A valve is disposed to adjust the pressure of the operating fluid that is force-fed from the pump. The controller performs an operation control of the pump and the valve to control the pressure of the operating fluid to be supplied to the brakes when the controller determines that the braking forces are to be applied to the vehicle. The controller controls a pressure-increasing gradient of a fluid pressure by controlling both the pump and the valve during a pressure-increasing control for increasing the pressure in the brakes.

Abstract: A releasable brake pedal system 10 for a vehicle includes a pedal assembly 12 operatively engageable by the driver of the vehicle and a hydraulic actuator assembly 20 for generating pressurized hydraulic fluid for actuating one or more brakes 44A-44D. The pedal system 10 further includes a pressure release valve 30 or 30′ coupled in fluid communication with the pressurized hydraulic fluid. The pressure release valve 30 or 30′ is operative to reduce the amount of pressure applied to the brakes 44A-44D during a detected vehicle deceleration indicative of a collision event. The pressure release valve 30 is responsive to a deceleration sensor 40 according to one embodiment, and valve 30′ employs a deceleration sensitive inertial mass 76 according to another embodiment. Accordingly, the pedal system 10 reduces forces that may otherwise be transferred to the pedal assembly 12 during a collision.

Abstract: A system and method for ABS stability control is provided, the method comprising the steps of determining whether a first wheel is in an ABS mode; determining whether the first wheel is in an apply mode; determining whether a second parallel wheel is in the release mode; calculating an adjusted wheel slip if the first wheel is in the ABS mode, the first wheel is in the apply mode, and the second parallel wheel is in the release mode; and determining a control mode for the first wheel using the adjusted wheel slip.

Abstract: A system and method for ABS stability control is provided, the method comprising the steps of determining whether a first wheel is in an ABS mode; determining whether the first wheel is in an apply mode; determining whether a second parallel wheel is in the release mode; calculating an adjusted wheel slip if the first wheel is in the ABS mode, the first wheel is in the apply mode, and the second parallel wheel is in the release mode; and determining a control mode for the first wheel using the adjusted wheel slip.

Abstract: An improved anti-lock brake control method adaptively determines exit criteria for terminating anti-lock brake control based on rate of brake pedal release and estimates of the brake torque and road surface coefficient of friction. The brake torque and road surface coefficient of friction are estimated based on a periodically updated characterization of the relationship between brake pedal position and vehicle deceleration.

Abstract: Road wheel accelerations are calculated in a controller from respective road wheel velocity values. Any one of the road wheel velocities, including the road wheel velocity of one of the road wheels that is a controlled system in an anti-lock brake control during a brake operation, is selected on the basis of a predetermined condition, any one of the road wheel accelerations is selected from among results of calculations of the road wheel accelerations which corresponds to one of the road wheel velocities which is selected so as to generate a control-purpose road wheel acceleration, and anti-lock brake control is executed for each road wheel during the brake operation using the selected road wheel velocity and the control-purpose road wheel acceleration so as to prevent a wheel's lock for each road wheel from occurring.

Abstract: An antilock control method wherein during the running of an automotive vehicle on a road surface (&mgr;-split surface) having a different coefficient of friction where one of the right and left wheels of the same axle is on a road surface of the higher coefficient of friction and the other one of the wheels is on a road surface of the lower coefficient of friction, when the brake is operated and an antilock control starts, the wheel that runs on the road surface having the lower coefficient of friction excessively slips in a first cycle of the antilock control, and a predetermined condition is satisfied, 1) a hydraulic braking pressure to the wheel that runs on the road surface having the higher coefficient of friction is progressively decreased during progressively decreasing periods of time, and 2) after the pressure decreasing, another predetermined condition is satisfied, a gentle increasing of the hydraulic braking pressure to the wheel that runs on the road surface having the higher coefficient of frict

Abstract: The present invention is directed to a system for detecting a difference in level on a road, wherein an acceleration sensor is provided for detecting an acceleration of a vehicle, and a wheel speed sensor is provided for detecting a wheel speed of at least one wheel of the vehicle. A wheel acceleration is calculated continuously on the basis of the wheel speed detected by the wheel speed sensor. It is determined if a variation of the signal output from the acceleration sensor is greater than a predetermined range. And, it is determined if the calculated wheel acceleration varied in the same direction as that of the variation of the signal output from the acceleration sensor, and then varied in the reverse direction to exceed a predetermined reference value. On the basis of the result of each determination, it is determined if the wheel ran over the difference in level on the road. If the affirmative result is obtained in each determination, the difference in level on the road can be detected.

Abstract: A moving behavior control device for a vehicle calculates first target braking forces to be applied to the respective wheels for stabilizing the vehicle against a turn instability, second target braking forces to be applied to the respective wheels for stabilizing the vehicle against a roll instability, and target overall braking forces to be applied to the respective wheels by integrating the first and second target braking forces, and applies braking forces to the respective wheels according to the target overall braking forces, wherein the applied braking forces are decreased according to a first rate schedule by which the applied braking forces are decreased at a first rate according to an excess of the applied braking forces relative to the target overall braking forces when the vehicle is running at no probability of rolling beyond a predetermined threshold roll, and according to a second rate schedule by which the braking forces are lowered at a second rate smaller than the first rate according to the

Abstract: A braking force control apparatus adapted to change a magnitude of a braking force produced in response to a braking operation based on a condition of the braking operation, and control a braking force in an appropriate manner meeting an operating feeling of a vehicle operator. The braking force control apparatus performs either a normal control to produce a braking force by a braking operation or a brake-assist control to produce an increased braking force larger than the braking force produced during the normal control. In the apparatus, a stroke sensor (299) detects a stroke amount (L) of a brake pedal (202). When a stroke amount (L) of the brake pedal (202) detected at a predetermined time (TST) after the normal control is changed to the brake-assist control is below a predetermined value (&agr;), the apparatus determines that a brake releasing operation is intended by the operator, and terminates the brake-assist control.

Abstract: An antilock brake control device of this invention includes a electronic control device 30 to operate antilock brake control and the hydraulic unit 20 which operates by a control signal from the electronic control device 30, wherein the maximum target amount of slip is preset, the rate of pressure reduction is determined so as to vary the amount of slip along a quadratic curve which regards the predetermined maximum target amount of slip as a extreme value, and the fluid pressure of the wheel cylinder is reduced at the rate of pressure reduction.

Abstract: An anti-skid control system has a determining device which determines whether no pressure increasing output is scheduled to be generated for any of pressure increasing valves provided for plural wheels for at least a predetermined time period. When no pressure increasing output is scheduled to be generated for any of the pressure increasing valves for at least the predetermined time period, the pressure increasing valves are controlled so that a pressure increasing operation is carried out for at least one wheel cylinder to allow brake fluid to flow from a master cylinder to the wheel cylinder.

Abstract: The solenoid control valves of a solenoid-operated automotive antilock braking system are cyclically controlled to enable the valves to operate in a stable, partially open position that provides a desired fluid flow while minimizing noise associated with acceleration and deceleration of the controlled fluid. After an incipient lock-up condition is detected and the solenoid valve has been energized to hold and/or permit a partial release of the brake pressure, the solenoid is initially de-energized for a defined interval designed to reduce the current to a scheduled value. In this interval, the solenoid current is re-circulated through a free-wheeling diode for a smooth decay, allowing the valve to slowly open in a smooth and stable fashion. Then the solenoid is pulse-width modulated (PWM) at a frequency and duty cycle designed to maintain the solenoid current at the scheduled value. The interval of PWM is relatively brief to avoid any instability associated with the current pulsation.

Abstract: An antiskid braking system for controlling hydraulic braking pressure to alleviate a lock of wheels so as thereby to control a skid of the wheel and alters the hydraulic braking pressure by repeating at least a pressure reducing phase and a pressure increasing phase so as to render the wheels loose to be locked more for a leading period of time from a commencement of antiskid braking control than for a succeeding period of time of antiskid braking control, or otherwise, if the control of hydraulic braking pressure for the gradual alleviation of the wheel lock is performed in consecutive cycles, in the first cycle of antiskid braking control than in any other remaining cycle.

Abstract: A braking force control apparatus for use with an automotive vehicle supported on road wheels each of which has a wheel cylinder for applying a braking force to the corresponding road wheel in response to a fluid pressure introduced thereto. The fluid pressure is controlled by a solenoid valve which is movable between open and closed positions in response to a control signal having a variable duty ratio. The duty ratio of the control signal is changed at predetermined intervals of time to move the solenoid valve in a plurality of steps toward the closed position.

Abstract: The wheel speeds are measured by wheel speed sensors and are fed to an evaluation circuit. By way of the evaluation circuit, brake pressure control signals at least for increasing pressure and for decreasing pressure for a specific duration are then produced for the closed-loop/open-loop control of the wheel movement behavior. Moreover, brake pressure control signals are also usually output by the evaluation circuit in order to keep the brake pressure constant. These brake pressure control signals are fed to brake pressure control units for varying the brake pressure. The core of the invention consists in the fact that the duration at least of the first decrease in brake pressure at the front wheels is selected to be dependent on the speed of the vehicle at the start of braking.

Abstract: A brake pressure controller, responsive to a wheel speed sensor and coupled to a brake, performs a cyclic control of pressure applied to the brake. A brake pressure cycle includes a pressure apply stage and a pressure dump stage having activation conditions based upon a slip threshold parameter. A predetermined base threshold quantity is modified in dependence upon a measured time duration of the pressure dump stage and/or a slip depth error quantity so that a greater amount of slip is added to the base slip threshold when braking on a deformable surface than when braking on a non-deformable surface.