Abstract: A brake system control apparatus comprising: a fluid brake system including a master cylinder containing a hydraulic fluid having a hydraulic pressure, a hydraulic pump having an output hydraulically coupled to the master cylinder, a motor coupled to and providing motive force to the hydraulic pump, a current sensing device coupled to the motor and providing an output signal indicative of electric current through the motor; and an electronic controller coupled to the current sensing device comprising a first sampler taking a first sample of the output signal a first time period after a start up of the motor, a second sampler taking a second sample of the output current a second time period after start up of the motor and a divider for determining a ratio of the first and second samples wherein the ratio is indicative of a hydraulic pressure in the master cylinder at the start up of the motor.

Abstract: According to the present invention, the gradient of duty pressure increase can be adjusted to a best possible value even when an M/C pressure has varied. For example, duty ratio is set to a first set value when a difference between the M/C pressure and a wheel locking pressure is equal to or larger than a predetermined value and to a second set value for a longer pressure increase duration when the difference is smaller than the predetermined value. Then, a brake fluid pressure control valve is operated so that the duty pressure can be increased according to the duty ratio.

Abstract: The present invention is directed to a vehicle motion control system for maintaining vehicle stability by controlling the braking force applied to each wheel of a vehicle. The braking force applied to each wheel is controlled on the basis of outputs of the wheel speed sensors and the vehicle speed estimation unit. A limit value is calculated to a difference between a first estimated vehicle speed calculated for a second wheel located on the right side of the vehicle and a left estimated vehicle speed calculated for a left wheel located on the left side of the vehicle. The calculation of one of the first and second estimated vehicle speeds is limited in response to the limit value, so as to keep the estimated vehicle speed calculated for one of the right and left wheels rotating at a relatively low speed to be greater than a value subtracting the limit value from the second estimated vehicle speed provided for the other one of the right and left wheels rotating at a relatively high speed.

Abstract: A braking control system for a motor vehicle in which various braking controls, including an antiskid braking control and a traction control, are realized comprehensively, accurately and smoothly without being based on the slip factor of a wheel. The actual wheel speed (Wvr) of the rear wheel side is detected, and the desired wheel speed (Wrf) of the front wheel side is set so as to be lower than the actual wheel speed (Wvr). Besides, the actual wheel speed (Wvf) of the front wheel side is detected, and the deviation (ef) between the actual wheel speed (Wvf) and the desired wheel speed (Wrf) is detected. Subsequently, the desired braking torque (Nrf) of the front wheel side is calculated from the deviation (ef) and the actual wheel speed (Wvf). Further, the desired braking torque (Nrr) of the rear wheel side is set on the basis of the desired braking torque (Nrf). The braking pressure of the braking apparatus is controlled so as to establish the desired braking torques (Nrf) and (Nrr).

Abstract: A method for controlling the brakes in an automotive vehicle. The vehicle has a velocity and a plurality of wheels, each wheel having an angular velocity and a brake which is operable by applying a pressure agent to the brake. An amount of the pressure agent to be applied to, or released from, each brake, individually, to implement a desired braking operation is determined. Switching times corresponding to the amounts of the pressure agent are calculated for opening and closing the inlet valve or outlet valve of each respective brake, individually. An estimated vehicle velocity and an estimated wheel angular velocity which result from applying the pressure agent to the brakes are determined. The actual velocity of the vehicle and the actual angular velocity of the wheels are determined by measuring the angular velocity, and determining the velocity based on the measurement.

Abstract: In an antiskid braking system for increasing or decreasing a braking force according to a wheel speed and a vehicle speed, an algorithm applied to the determination of a braking force decrease amount is improved. Once a target braking force decrease amount is determined according to the wheel speed and vehicle speed, this is compared with a predetermined minimum decrease amount, and when the target decrease amount is less than the minimum decrease amount, braking force is decreased according to the minimum decrease amount. The minimum decrease amount is preferably determined according to the braking force immediately before the braking force decrease. In this way, braking force reduction insufficiencies in several conditions are prevented.

Abstract: An adaptive brake control method, for a motor vehicle with first and second front vehicle wheels and third and fourth rear vehicle wheels, is achieved according to the steps of: receiving an operator input brake command; responsive to a brake command function stored in memory and the operator input brake command, developing a rear brake position command; outputting the rear brake position command to a rear brake actuator; monitoring the first and second front wheel speeds and the third and fourth rear wheel speeds; responsive to the monitored first and second front wheel speeds and the monitored third and fourth rear wheel speeds, updating the brake command function stored in memory, wherein the brake position command table is adaptively updated and a front to rear brake proportioning of the vehicle is adaptively controlled to minimize a difference between the front and rear wheel speeds during braking.

Abstract: A method of brake control, comprising the steps of: determining a deceleration of a vehicle; measuring a first wheel rotational velocity of a front wheel of the vehicle; measuring a second wheel rotational velocity of a rear wheel of the vehicle; determining a front wheel normalization value responsive to the deceleration and a front tire deformation constant; determining a rear wheel normalization value responsive to the deceleration and a rear tire deformation constant; determining a front normalized wheel rotational velocity responsive to the front wheel normalization value and the first wheel rotational velocity, wherein the front normalized wheel rotational velocity is responsive to a front tire deformation that occurs during a braking maneuver of the vehicle; determining a rear normalized wheel rotational velocity responsive to the rear wheel normalization value and the second wheel rotational velocity, wherein the rear normalized wheel rotational velocity is responsive to a rear tire deformation that o

Abstract: Methods and systems for detecting aquaplaning of a vehicle both before and during braking in a vehicle anti-lock brake system (ABS) when the front wheels experience deep and substantial slip and tend not to recover. The system includes a wheel speed sensor for measuring the speed of each of the vehicle wheels, and a control unit for determining whether the anti-lock brake system should be activated without the need for applying a test braking pressure.

Abstract: Wheel speed sensor signals are monitored to determine whether physically impossible values of change in wheel speed occur during wheel acceleration. Changes are compared to two different comparison thresholds which are brought into effect alternately depending on whether the wheel is found to be accelerating continuously or not.

Abstract: In an electronically controlled braking system which incorporates anti-lock brake control and includes a plurality of brake pressure control valves having associated local electronic control units which communicate with a master electronic control unit, part of the anti-lock brake control logic for a wheel is performed by the electronic control unit associated with the pressure control valve for that wheel, with the remainder of the anti-lock brake control logic for that wheel being performed by the master electronic control unit. The local valve-associated electronic control unit includes skid detection logic which causes the brake pressure at the associated wheel to be reduced in response to a wheel skid detected thereby, brake pressure at that wheel being controlled thereafter, at least for a defined period, according to demands communicated to the local control unit from the master control unit.

Abstract: A method for estimating hydraulic pressure in a control system that includes hydraulic pressure actuators (28,30) remotely situated with respect to a pressure source (14) wherein pressure at the remote location can be estimated thereby eliminating the need for using pressure transducers to obtain a pressure signal for use in an electronic controller (86,90,142) based on a calibratable relationship between estimated brake pressure and the difference in the volume of fluid flowing toward the pressure actuator and from the pressure actuator. An effective duty cycle for a solenoid operated fluid flow control valve (60,62) in the actuator circuit is determined in accordance with an empirical relationship between the difference between (i) the estimated brake pressure and the supply pressure and (ii) a commanded duty cycle.

Abstract: An antiskid control device which calculates an estimated fluid pressure of each of wheel cylinders under antiskid control in each control cycle so as to adjust a fluid pressure of each of the wheel cylinders on the basis of the estimated fluid pressure and behaviors of the wheels. The device includes a differential pressure detecting member which detects a difference between a fluid pressure of a master cylinder and the fluid pressure of each of the wheel cylinders so as to produce an output signal indicative of the difference between the fluid pressure of the master cylinder and the fluid pressure of each of the wheel cylinders. When the difference between the fluid pressure of the master cylinder and the fluid pressure of each of the wheel cylinders is found to be in the vicinity of zero, the estimated fluid pressure of each of the wheel cylinders is set to a predetermined value by stopping addition in calculation of the estimated fluid pressure.

Abstract: An anti-skid brake control system (9) for a wheeled vehicle has a conventional continuous source of pressurized hydraulic fluid, a hydraulically actuated wheel rotation braking device which responds via a wheel brake valve (11) to applied hydraulic pressure to apply a braking force to a wheel of the vehicle, and an operator actuatable control (10, 12, 39) for varying the supply of hydraulic pressure to the wheel rotation braking device. The system is responsive directly to the operator actuatable control (10, 12, 39) for determining the deceleration (14) currently commanded by the operator and further dynamically determines a maximum permissible wheel deceleration (47) at a given time. The operator controlled supply of hydraulic pressure to the braking device is overridden in the event that the deceleration (14) currently commanded by the operator exceeds the maximum permissible wheel deceleration.

Abstract: An anti-lock braking system of a motor vehicle has at least three road wheels. The system comprises respective hydraulically actuating units for the road wheels. Each actuating unit feeds a brake cylinder of the corresponding road wheel with a brake pressure upon braking.

Abstract: A brake pressure control apparatus for regulating a brake pressure for braking a wheel of a motor vehicle, including a device for obtaining a rotating speed of the wheel, a pressure regulator for regulating the brake pressure, on the basis of the rotary speed of the wheel, a running speed of the vehicle and an optimum slip amount of the wheel, a device for estimating a future speed of the wheel, on the basis of values of the wheel speed which have been obtained by the wheel speed obtaining device, and a device for reflecting the future speed of the wheel on the determination of a point of time at which the wheel brake pressure is regulated by the pressure regulator.