Abstract: A brake control device is provided, which is capable of providing a precise diagnosis on a trouble on a hydraulic pressure valve etc., so as to provide an appropriate output hydraulic pressure corresponding to a stroke amount of a brake pedal. In this device, an electromagnetic valve is provided on a hydraulic pressure passage allowing an auxiliary hydraulic pressure chamber to communicate with an accumulator, and is controlled to open when such a trouble occurs that output hydraulic pressure from the hydraulic pressure valve becomes lower than a predetermined range; and an electromagnetic valve is also provided on a hydraulic pressure passage allowing the auxiliary hydraulic pressure chamber to communicate with a reservoir, and is controlled to open when such a trouble occurs that the output hydraulic pressure from the hydraulic pressure valve becomes insufficiently reduced.

Abstract: A normally closed secondary solenoid opening/closing valve 36 is provided along a secondary branched fluid pipe 35 establishing a communication between an accumulator 11 and a reservoir 8 through a fluid pressure input side to a fluid pressure output side of a regulator valve 3, and in the event that a fluid pressure supplied to the regulator valve 3 decreases down to or lower than a predetermined range due to something abnormal occurring in the accumulator 11, the state of the secondary solenoid opening/closing valve 36 is changed over from a closed state to an opened state, whereby a residual pressure in the accumulator 11 and a residual pressure in the output fluid pressure chamber 15 can be released through the reservoir 8 which is in communication therewith through an output fluid pipe 31 and the secondary branched fluid pipe 35 along which the secondary opening/closing valve 36 is provided.

Abstract: A brake control device is provided, which is capable of providing a precise diagnosis on a trouble on a hydraulic pressure valve etc., so as to provide an appropriate output hydraulic pressure corresponding to a stroke amount of a brake pedal. In this device, an electromagnetic valve is provided on a hydraulic pressure passage allowing an auxiliary hydraulic pressure chamber to communicate with an accumulator, and is controlled to open when such a trouble occurs that output hydraulic pressure from the hydraulic pressure valve becomes lower than a predetermined range; and an electromagnetic valve is also provided on a hydraulic pressure passage allowing the auxiliary hydraulic pressure chamber to communicate with a reservoir, and is controlled to open when such a trouble occurs that the output hydraulic pressure from the hydraulic pressure valve becomes insufficiently reduced.

Abstract: A normally closed secondary solenoid opening/closing valve 36 is provided along a secondary branched fluid pipe 35 establishing a communication between an accumulator 11 and a reservoir 8 through a fluid pressure input side to a fluid pressure output side of a regulator valve 3, and in the event that a fluid pressure supplied to the regulator valve 3 decreases down to or lower than a predetermined range due to something abnormal occurring in the accumulator 11, the state of the secondary solenoid opening/closing valve 36 is changed over from a closed state to an opened state, whereby a residual pressure in the accumulator 11 and a residual pressure in the output fluid pressure chamber 15 can be released through the reservoir 8 which is in communication therewith through an output fluid pipe 31 and the secondary branched fluid pipe 35 along which the secondary opening/closing valve 36 is provided.

Abstract: A brake control apparatus comprising a brake fluid pressure sensor for detecting the brake fluid pressure of the wheel cylinder for a braking system. That is, the brake fluid pressure sensor detects the condition of braking. The brake fluid pressure is controlled. The brake fluid pressure is increased based on a predetermined pressure increase gradient in the initial stage of the automatic braking, and is decreased based on a predetermined pressure decrease gradient in the latter stage of the automatic braking.

Abstract: A first signal is obtained by detecting speed of wheels of a vehicle to indicate the wheel speed. On the other hand, a second signal is obtained by detecting longitudinal acceleration to directly indicate longitudinal acceleration of the vehicle. A third signal indicating the change rate of the wheel speed is obtained by differentiating the first signal by time. The third signal is sensitive to a small convex or concave of the road surface but not sensitive to a longitudinal inclination of the road surface. The second signal is not sensitive to a small convex or concave of the road surface but is sensitive to a longitudinal inclination of the road surface. Then, a fourth signal is obtained from the second signal by filtering low frequency components off therefrom, while a fifth signal is obtained from the third signal by filtering high frequency components off therefrom. Then, a final longitudinal acceleration signal is obtained by composing the fourth and fifth signals together.