Aisin Seiki Kabushiki Kaisha

Toyota Jidosha Kabushiki Kaisha

Other

Takayuki Itoh

Kenji Tozu

Masanobu Fukami

Norio Yamazaki

Yoshiyuki Yasui

Satoshi Yokoyama

Jun Mihara

Shoji Inagaki

Noriaki Hattori

Seiichi Kojima

Masaki Yamamoto

Yoshiharu Nishizawa

Shingo Sugiura

Toshihisa Kato

Hiroyuki Yamaguchi

Katsuhiro Asano

Akitaka Nishio

Hiromu Kuromitsu

Kenji Tanaka

Akio Sakai

The present invention is directed to a brake control system for a vehicle, which includes a cut-off valve for opening or closing a main passage, which communicates a master cylinder with a wheel brake cylinder, and a pump for discharging the pressurized brake fluid to the wheel brake cylinder, with an outlet of the pump connected to a position between the cut-off valve and the wheel brake cylinder. An inlet valve is provided for opening or closing an auxiliary passage which communicates an inlet of the pump with the master cylinder. And, a controller is adapted to place the cut-off valve in a closed position thereof, place the inlet valve in an open position thereof, and actuate the pump to supply the pressurized brake fluid discharged from the pump into the wheel brake cylinder, when a brake-assist control is to be performed. A detection device such as a pressure sensor is provided for detecting an amount of operation of a brake pedal, so that the controller controls an amount of operation of the pump in response to variation of the amount of operation of the brake pedal detected by the detection device.

Brake control system for a vehicle

The present invention is directed to a brake control system for a vehicle, wherein a first valve device for opening or closing a main passage, a hydraulic pressure pump, and a second valve device for opening or closing an auxiliary passage are disposed in each hydraulic pressure circuit of a dual hydraulic pressure circuit system. At least one of the first and second valve devices is controlled to equalize the slip rates of a pair of wheels, with the wheel brake cylinders operatively mounted thereon and disposed in different hydraulic circuits, and placed at the left side and right side of the vehicle, respectively, when a difference between the slip rates of the wheels placed at the left side and right side exceeds a predetermined value.

A vehicle running condition judgment device for accurately detecting a change in a road surface condition and a vehicle's limit running condition. With substitution of respective tire characteristics and a detected state quantity into a vehicle motion model, vehicle slip angles are estimated for respective assumed road surface conditions. Based on the current state quantity and the last estimated vehicle slip angle, currently estimated vehicle slip angles for the respective assumed road surface conditions are compensated. A differential operation section calculates an estimation value of a vehicle slip angular velocity for each of the assumed road surface conditions based on the compensated vehicle slip angles for the respective assumed road surface conditions. Meanwhile, an operation section calculates a detection value of a vehicle slip angular velocity based on the detected state quantity. By comparing the detection value and the respective estimation values for the assumed road surface conditions, the current road surface condition is determined. Further, a lateral acceleration is calculated based on a vehicle slip angle, and compared with the detection value for determination of the road surface condition, and also with a predetermined limit value for determination of a vehicle's limit running condition.

Vehicle running condition judgement device

The present invention is directed to a vehicle motion control system, which includes a hydraulic braking pressure control apparatus for controlling braking force applied to each wheel of a vehicle at least in response to depression of a brake pedal. A vehicle condition monitor is disposed in the vehicle for monitoring a condition of the vehicle in motion, and a vehicle condition determining device is provided for determining stability of the vehicle in motion, including a turning motion of the vehicle on the basis of the output of the monitor. A braking force controller is provided for controlling the pressure control apparatus in response to the result of determination of the vehicle condition determining device to control the braking force applied to each wheel of the vehicle. A starting reference setting device is provided for setting a starting reference to start the braking force control by the braking force controller in response to the result of determination of the vehicle condition determining device. Then, an error estimating device is provided for estimating an error caused by the monitor, and a correction device is provided for correcting the starting reference set by the starting reference setting device in response to the error estimated by the error estimating device.

Vehicle motion control system

The present invention is directed to a brake control system for a vehicle, wherein a first valve device for opening or closing a main passage, which communicates a master cylinder with wheel brake cylinders, a hydraulic pressure pump for supplying the hydraulic pressure to the main passage, and a second valve device for opening or closing an auxiliary passage, which communicates the inlet of the pressure pump with the master cylinder, are disposed in each hydraulic pressure circuit of a dual hydraulic pressure circuit system. In the case where the slip rate of at least one of the front wheels is smaller than the slip rate of at least one of the wheels belonging to a different hydraulic pressure circuit from the hydraulic pressure circuit to which the one of the front wheels belongs, when the brake pedal is being operated, the hydraulic braking pressure discharged from the pressure pump is applied to one of the wheel brake cylinders operatively mounted on at least one of the front wheels, by controlling the second valve device for example.

A brake control apparatus includes a first valve to open and close a main line between a master cylinder and a wheel cylinder, a pump connected between a first valve and the wheel cylinder to supply pressurized brake fluid to the wheel cylinder, an auxiliary line connecting the inlet side of the pump to a master cylinder, a second valve to open and close the auxiliary line, a pressure sensor to detect the output pressure of the master cylinder and an electronic control unit which controls the first valve, the second valve, and the pump based upon the pressure detected by the pressure sensor so that the wheel cylinder receives a higher pressure than that of the master cylinder. The electronic control unit also closes the second valve while the pressure sensor detects the pressure over a certain pressure determined by the road surface condition.

Brake control apparatus

A brake control apparatus includes a first valve for opening and closing a main line, a pump having an inlet port and an outlet port to supply pressurized brake fluid to a point between the main line and the wheel cylinder, an auxiliary line Mfc connecting the inlet port of the pump to a master cylinder, a second valve for opening and closing the auxiliary line, a brake operation sensor for detecting the operation of a brake pedal, and an electronic controller which controls the first valve, the second valve, and the hydraulic pump. The electronic controller judges the need for brake assist control based on the detection by the brake operation sensor and controls the first valve, the second valve and the pump to perform the brake assist control. The electronic control unit also controls the duty ratio for the second valve based on the detection of the brake operation sensor. According to the present invention, the duty ratio is determined based on the detection of the brake operation sensor when the brake assist control is judged to be necessary. The electronic control unit immediately drives the second valve with the determined duty ratio so that the pressure is promptly increased in the wheel cylinder in accordance with the driver's operation of the brake pedal.

Brake control apparatus including duty controlled valve

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.

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.

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 brake control system, which includes a first pressure circuit and a second pressure circuit for communicating a master cylinder with two sets of wheel cylinders, respectively. In each pressure circuit, a modulator is arranged to modulate the braking pressure in each wheel cylinder, a pressure pump is disposed to supply pressurized brake fluid to each wheel cylinder through each modulator, a normally open first valve is arranged to open or close a first passage for communicating the master cylinder with the modulator, and a normally closed second valve is arranged to open or close a second passage for communicating a reservoir directly with the inlet of each pump, or communicating the reservoir with it through the master cylinder. The pressurized brake fluid is supplied to each pressure circuit including the second valve at the inlet of the pump to perform an auxiliary pressurization. In the case where at least the second valve in the first pressure circuit opens the second passage, and the auxiliary pressurization is performed, the communication between the wheel cylinders in the second pressure circuit is blocked, when the brake pedal is not depressed, and the wheel cylinders in the second pressure circuit is communicated with the master cylinder, when the brake pedal is depressed.

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.

Growing community of inventors

Nagoya, Japan

Takayuki Itoh