Data processing: vehicles – navigation – and relative location – Vehicle control – guidance – operation – or indication – Indication or control of braking – acceleration – or deceleration
Reexamination Certificate
2001-07-24
2002-10-08
Beaulieu, Yonel (Department: 3661)
Data processing: vehicles, navigation, and relative location
Vehicle control, guidance, operation, or indication
Indication or control of braking, acceleration, or deceleration
C701S078000, C303S133000, C303S155000
Reexamination Certificate
active
06463378
ABSTRACT:
This application is based on and claims priority under 35 U.S.C. §119 with respect to Japanese Patent Application No. 2000-222892 filed on Jul. 24, 2000, the entire content of which is incorporated herein by reference.
FIELD OF THE INVENTION
This invention generally relates to a brake control device for a vehicle. More particularly, the present invention pertains to a vehicle brake control device having a hydraulic pressure generating device operable in response to operation of a brake pedal and operable independently of operation of the brake pedal. The present invention is applicable specifically for use in steering control by braking (vehicle slide slip preventing control) and traction control.
BACKGROUND OF THE INVENTION
A known brake control device for a vehicle is disclosed in published European Patent Application No. 0 379 329 A2 which corresponds to a Japanese Patent Application published as Toku-Kai-Hei 2(1990)-241863). This known brake control device includes a master cylinder for generating a hydraulic pressure to be supplied to wheel brake cylinders associated with road wheels of the vehicle, a booster for activating the master cylinder in response to operation of a brake pedal, an electro-magnetic valve device for activating the booster independently of the operation of the brake pedal, and a plurality of modulators interposed between the master cylinder and each of the wheel cylinders for regulating the hydraulic pressure to the corresponding wheel brake cylinder supplied from the master cylinder. When the driving road wheel is spinning, the booster is automatically activated by the electro-magnetic valve device to activate the master cylinder. Braking torque is applied to a controlled road wheel which is spinning, independently of a brake pedal operation, so that traction control is executed. While the traction control is being executed, the non-controlled road wheel, which is not driven, is disconnected from the master cylinder.
According to this known brake control device, the non-controlled road wheel is always disconnected from the master cylinder while the traction control is being executed. When the brake pedal is depressed by a driver when the traction control is being executed, a vehicle deceleration corresponding to the brake pedal depression is not able to be generated. Further, when this known brake control device is applied for use in other automatic brake control devices including steering control by braking, the same drawback occur.
Thus, this known vehicle brake control device is susceptible of certain improvements with respect to generating vehicle deceleration corresponding to the brake pedal depression when the brake pedal is depressed while the automatic brake control is being applied to the controlled road wheel.
Accordingly, a need exists for an improved brake control device which generates vehicle deceleration corresponding to brake pedal depression when the brake pedal is depressed while the automatic brake control is being performed. A need also exists for a an improved brake control device that is able to achieve sufficient brake pedal operation when the brake operation is performed by the driver.
SUMMARY OF THE INVENTION
According to an aspect of the present invention, a brake control device for a vehicle includes a brake pedal, a brake pedal operational condition detecting device for detecting an operational condition of the brake pedal, first and second wheel brake cylinders responsive to supplied hydraulic pressure for applying brake torque to the first and second road wheels, respectively, and a hydraulic pressure generating device for generating hydraulic pressure in response to operation of the brake pedal and for generating hydraulic pressure independently of the operation of the brake pedal. The hydraulic pressure generating device is hydraulically connected to the first and second wheel cylinders. A hydraulic pressure control valve device is disposed between the hydraulic pressure generating device and the first wheel brake cylinder for regulating hydraulic pressure in the first wheel cylinder supplied from the hydraulic pressure generating device, and is disposed between the hydraulic pressure generating device and the second wheel brake cylinder for regulating hydraulic pressure in the second wheel brake cylinder supplied from the hydraulic pressure generating device independently of regulation for hydraulic pressure in the first wheel brake cylinder. A first control device responsive to vehicle motion under the non-operated condition of the brake pedal is provided for activating the hydraulic pressure generating device, and for activating the hydraulic pressure control valve device to supply hydraulic pressure to one of the first and second wheel brake cylinders corresponding to one of the first and second road wheels to be controlled in response to the vehicle motion and to regulate hydraulic pressure in the one wheel brake cylinder, and to inhibit supplying hydraulic pressure to the other of the first and second wheel brake cylinders corresponding to the other of the first and second road wheels to be not controlled in response to the vehicle motion. In addition, a second control device responsive to the brake pedal operational condition detected by the brake pedal operational condition detecting device under the activated condition of the hydraulic pressure control valve device by the first control means controls the operation of the hydraulic pressure control valve device to supply hydraulic pressure to the other wheel brake cylinder without obstructing hydraulic pressure regulating performance of the first control means with respect to the one wheel brake cylinder.
Therefore, when the brake pedal is operated under the automatic brake control by the first control means, a proper response to the brake pedal operation is generated.
The brake control device for the vehicle further includes a vehicle deceleration detecting device for detecting or estimating vehicle deceleration. The second control device includes a target vehicle deceleration calculating mechanism for calculating the target vehicle deceleration on the basis of the brake pedal operational condition detected by the brake pedal operational condition detecting device, a vehicle deceleration comparing mechanism for comparing the target vehicle deceleration calculated by the target vehicle deceleration calculating mechanism with the vehicle deceleration detected or estimated by the vehicle deceleration detecting mechanism, and a valve control device responsive to an output by the vehicle deceleration comparing mechanism for controlling the pressure control valve device so that the vehicle deceleration resembles the target vehicle deceleration by regulating the brake pressure in the other wheel brake cylinders. The brake pedal operational condition detecting device includes a stroke sensor for detecting the operational stroke of the brake pedal. The valve control device controls the operation of the hydraulic pressure control valve device so as to increase hydraulic pressure in the other wheel brake cylinder when the vehicle deceleration becomes equal to the target vehicle deceleration.
Therefore, when the automatic brake control is performed when the brake pedal is being operated, vehicle deceleration corresponding to the brake pedal operation is generated. The wheel brake cylinders associated with all the road wheels are prevented from being cut off from the master cylinder and a sufficient brake pedal operation is thus achieved when the brake operation is performed by the driver.
It is preferable that the first control device performs a steering control by braking or a traction control. The steering control by braking is performed for activating the hydraulic pressure control valve device to supply the brake pressure to the one wheel cylinder in accordance with the vehicle motion under the oversteer restraining control or understeer restraining control when the brake pedal is under the non-controlled operation and for applying braking force to a vehicle portion
Beaulieu Yonel
Donnolly Arthur D.
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