Aisin Seiki Kabushiki Kaisha

Toyota Jidosha Kabushiki Kaisha

Norio Yamazaki

Kenji Tozu

Takayuki Itoh

Yoshiyuki Yasui

Masanobu Fukami

Jun Mihara

Shoji Inagaki

Noriaki Hattori

Seiichi Kojima

Masaki Yamamoto

Shingo Sugiura

Hiromu Kuromitsu

Satoshi Yokoyama

Yoshiharu Nishizawa

The present invention is directed to a hydraulic braking system for an automotive vehicle, wherein a first passage is provided for communicating a master cylinder with first and second wheel cylinders. First and second pressure control devices are disposed in the first passage to control the hydraulic pressure of the brake fluid in the first and second wheel cylinders, respectively. A second passage is provided for communicating the master cylinder with an inlet of an auxiliary pressure source, which introduces the brake fluid from the wheel cylinders, and discharges the pressurized brake fluid to the wheel cylinders through the pressure control devices. A valve device is disposed in the first passage and connected to the second passage to selectively place one of a first operating position for communicating the master cylinder with the pressure control devices and blocking the communication between the master cylinder and the inlet of the auxiliary pressure source, and a second operating position for communicating the master cylinder with the inlet of the auxiliary pressure source and blocking the communication between the master cylinder and the pressure control devices. At least an auxiliary passage is provided for communicating the master cylinder with at least one of the wheel cylinders. And, at least a switching valve is disposed in the auxiliary passage to open and close the auxiliary passage.

Hydraulic braking system for an automotive vehicle

The present invention is directed to a brake control system for a vehicle, which includes a master cylinder for pressurizing the brake fluid to discharge a master cylinder pressure in response to depression of a brake pedal, a modulator disposed between the master cylinder and a wheel brake cylinder for selecting a pressure control mode out of rapid pressure increase, pulse pressure increase, pulse pressure decrease, rapid pressure decrease and hold modes, a hydraulic pressure pump for discharging the pressurized brake fluid to the wheel brake cylinder through the modulator, and a reservoir for storing the brake fluid drained from the wheel brake cylinder through the modulator. A normally open first switching valve is disposed between the master cylinder and the modulator, and a normally closed second switching valve is disposed between the master cylinder and an inlet of the pressure pump. The first switching valve is placed in its closed position when the braking pressure in the wheel brake cylinder is to be pressurized automatically, while the second switching valve is actuated to communicate the master cylinder with the pressure pump only when the braking pressure in the wheel brake cylinder is being increased by the modulator.

Brake control system for a vehicle

The present invention is directed to a vehicle motion control system for maintaining vehicle stability by controlling a braking force applied to each wheel of the vehicle. In the system, a control map setting unit is adapted to set plural control maps with an x-axis of a slip rate deviation between a desired slip rate and an actual slip rate, and a y-axis of a vehicle acceleration deviation between a vehicle acceleration and a wheel acceleration for each wheel, respectively. Each control map has an origin determined by the desired slip rate and the vehicle acceleration provided for each control mode. A pressure mode setting unit is adapted to set a pressure mode for a pressure control apparatus in each control mode. The pressure mode is set according to a location determined by the slip rate deviation and the vehicle acceleration deviation on the control map. A reference map setting unit is adapted to set a reference map with an x-axis of the slip rate and a y-axis of the vehicle acceleration. A pressure mode selection unit is adapted to select one of the plural pressure modes according to a predetermined priority, when the control maps are superimposed on the reference map to set the control modes for each wheel. The pressure control apparatus is adapted to control the hydraulic pressure in the wheel cylinder in accordance with the selected pressure mode.

Vehicle motion control system

The present invention is directed to a braking force control system for an automotive vehicle having a hydraulic braking pressure control apparatus which is provided for applying the braking force to each of front and rear wheels of the vehicle at least in response to depression of a brake pedal. A desired yaw rate is set in accordance with a motion of the vehicle, and an actual yaw rate of the vehicle is measured. A varying rate of the desired yaw rate is calculated, and a varying rate of the actual yaw rate is calculated. Then, a deviation between the varying rate of the desired yaw rate and the varying rate of the actual yaw rate is calculated. And, a limitation unit is provided for actuating the hydraulic braking pressure control apparatus to limit the varying rate of the actual yaw rate by applying the braking force to at least one of the wheels, when the deviation exceeds a predetermined value. The limitation unit may be so constituted as to apply the braking force to a front wheel of the wheels which is located on the outside of a curve in the vehicle's path.

Braking force control system for an automotive vehicle

The present invention is directed to a monitor system for use in an automotive vehicle which includes wheel brake cylinders operatively mounted on wheels, respectively, and which includes a hydraulic pressure control apparatus for generating a hydraulic braking pressure in response to depression of a brake pedal. A difference calculating unit calculates a difference between a wheel speed of a wheel to be determined and a wheel speed of at least one reference wheel which is compared with a predetermined value, when a braking operation detection unit detects a braking operation. Then, a determination unit compares the difference with a predetermined value, and determines that the pressure circuit provided for the wheel to be determined is normal, when the difference is lower than the predetermined value. An output unit may be provided to produce an output signal when a period of time during which the difference continues to be equal to or greater than the predetermined value, exceeds a predetermined time.

Monitor system for hydraulic pressure circuits of vehicles

The present invention is directed to a vehicle motion control system for maintaining vehicle stability by controlling the braking force applied to at least one wheel of a vehicle. A vehicle condition monitor is provided for monitoring a condition of the vehicle in motion. The braking force is applied by a braking apparatus to each wheel in response to depression of a brake pedal, and on the basis of an output of the monitor and irrespective of depression of the brake pedal. A control variable is provided for actuating the braking apparatus and set in accordance with at least a first parameter (e.g., wheel acceleration) and a second parameter (e.g., slip rate) which are provided on the basis of the output of the monitor, respectively, so that the control variable is varied in response to the output of the monitor. The control variable is integrated during the braking apparatus is actuated. The actuation of the braking apparatus starts when the control variable exceeds a predetermined level in magnitude, and is terminated when the control variable is within a predetermined zone provided in accordance with the first parameter and the second parameter, and when the controlled variable is less than a predetermined value.

Vehicle motion control system for immediately terminating braking

The present invention is directed to a vehicle motion control system for maintaining stability of an automotive vehicle when the vehicle is in motion, by controlling a hydraulic braking pressure control apparatus to control a hydraulic braking pressure in each of wheel brake cylinders operatively mounted on each wheel of the vehicle to control a braking force applied thereto. A steering control unit and an anti-skid control unit are provided for actuating the apparatus to control the braking force applied to at least one of the wheels, respectively. A pressure increase compensating unit is provided for controlling a pressure increasing rate for increasing the braking pressure in at least one of the wheel brake cylinders to a desired pressure which is set after the pressure decreasing operation when the braking pressure with respect to at least one of the wheels is controlled in accordance with the control performed by the steering control unit and the control performed by the anti-skid control unit simultaneously, to be greater than a pressure increasing rate for increasing the braking pressure to the desired pressure in accordance with the control performed only by the anti-skid control unit.

The present invention is directed to a vehicle motion control system for maintaining vehicle stability by controlling the braking force applied to at least one of the driven wheels and non-driven wheels of a vehicle. A vehicle motion control is performed by applying the braking force to at least one wheel, on the basis of a condition of the vehicle in motion and irrespective of depression of a brake pedal. The braking force is applied to at least one wheel so as to cause an increase in turning radius, when an excessive oversteer occurs during vehicle motion. Whereas, the braking force is applied to at least one wheel so as to cause a decrease in turning radius, when an excessive understeer occurs during vehicle motion. In the case where an excessive braking to at least one of the driven wheels is detected, when an engine brake is exerted on the vehicle, a correction control is performed to increase the braking force applied to at least one of the non-driven wheels. For example, when an excessive slip rate of at least one of the driven wheels is detected, a desired slip rate of at least one of the non-driven wheels is corrected.

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. For example, the limit value is calculated on the basis of a varying value resulted from at least a change in a coefficient of friction for each wheel of the vehicle, and varied in accordance with one of a plurality of control modes.

The present invention is directed to a vehicle motion control system for maintaining vehicle stability by controlling the braking force applied to at least one of the front and rear wheels of a vehicle. Oversteer restraining control and/or understeer restraining control are performed by applying the braking force to at least one wheel, on the basis of a condition of the vehicle in motion and irrespective of depression of a brake pedal. In the oversteer restraining control, the braking force is applied to at least one wheel so as to cause an increase in turning radius, when an excessive oversteer occurs during vehicle motion. Whereas, in the understeer restraining control, the braking force is applied to at least one wheel so as to cause a decrease in turning radius, when an excessive understeer occurs during vehicle motion. When the excessive oversteer and excessive understeer occur simultaneously or sequentially during vehicle motion, priority is given to the oversteer restraining control over the understeer restraining control with respect to at least one of the front wheels, while priority is given to the understeer restraining control over the oversteer restraining control with respect to at least one of the rear wheels.

Vehicle motion control system involving priority oversteer and

The present invention is directed to a vehicle motion control system for maintaining vehicle stability by controlling the braking force applied to at least one wheel of a vehicle. A vehicle condition monitor monitors a condition of the vehicle in motion. A steering control unit actuates a braking unit to apply the braking force to at least one wheel on the basis of the output of the monitor and irrespective of depression of a brake pedal. An anti-skid control unit actuates the braking unit to control the braking force applied to at least one wheel in response to a rotational condition thereof during braking. A subordinate control unit actuates the braking unit to adjust the braking force control performed by the anti-skid control unit, in accordance with a predetermined relationship between the anti-skid control unit and the subordinate control unit. And, a priority control unit is adapted to give priority the anti-skid control unit over the steering control unit, and give priority the steering control unit over the subordinate control unit, when the condition for starting the braking force control performed by both of the anti-skid control unit and the steering control unit is fulfilled with respect to at least one wheel.

A wheel brake pressure controlling system includes a brake pressure operating circuit for selectively supplying to a wheel brake a primary pressure generated by a vacuum booster in response to the depression of a brake pedal and a secondary pressure generated by a hydraulic pressure pump which is driven by an electric motor, a microcomputer for estimating a turning of vehicle, determining if a turning of the vehicle is in a over- or under-steer region, and for determining a wheel brake, the pressure of which is to be intensified if the turning of the vehicle lies in the over- or under-steer region, and an output controller for supplying the secondary pressure to the wheel brake which has been thus determined, through the brake pressure operating circuit. The microcomputer determines if the turning of a vehicle occurs in a reference region located outside the over- or under-steer region, and whenever the turning of the vehicle occurs in the reference region, drives the second source of pressure for generating the secondary pressure, determines a wheel brake which is to be intensified, and automatically intensifies the wheel brake.

Wheel brake pressure controlling system in which vehicle operating

A brake force distribution control system comprising wheel speed sensing means S1, S3 which detect wheel speeds VWFR, VWRR of a front right wheel FR and a rear right wheel RR respectively, standard speed calculating means M1 calculating first speed value B and second speed value C from each of the wheel speeds VWFR, VWRR, and figuring out front medium value of VWFR, B and C and rear medium value of VWFR, B and C as standard wheel speeds VWSFR, VWSRR respectively, comparison means M2 calculating a difference between the standard wheel speeds VWSRR and VWSFR and driving means M3 operating a pressure control valve unit FV depending on the differences so as to modulate brake force of the rear right wheel RR relative to that of the front right wheel FR.

Distribution system for selectively controlling and supplying brake

In an electric control apparatus for a hydraulic brake control system of a vehicle, a feedback control portion is provided to produce a feedback control pulse signal indicative of a difference between a target slip ratio and an actual slip ratio. A feedforward control portion is provided to successively convert the target slip ratio in relation to a required braking force, a hydraulic braking pressure and an amount of hydraulic braking fluid, in sequence, and to convert the amount of hydraulic braking fluid into a feedforward control pulse signal. A pulse mixing circuit is connected to control portions to mix the control pulse signals for producing a mixed control pulse signal as a distinct control pulse signal. A driving circuit is connected to the pulse mixing circuit to control a hydraulic braking pressure applied to each wheel of the vehicle in accordance with the control pulse signal, regardless of the extent to which a brake pedal of the vehicle is depressed.

Growing community of inventors

Kariya, Japan

Norio Yamazaki