Abstract: A brake booster pressure control apparatus is provided for controlling the vacuum pressure of a brake booster, the brake booster assisting a braking operation on a brake pedal by using an intake air pressure. The brake booster pressure control apparatus includes a brake-pedal vibration detecting unit that outputs a signal indicative of occurrence of vibrations of the brake pedal. A pressure control unit controls the pressure of the brake booster based on the signal output by the brake-pedal vibration detecting unit.

Abstract: Hydraulic pressure control apparatus including a hydraulic pressure source device operable according to a control amount, to generate an output pressure thereof on the basis of a fluid pressure corresponding to an operating force of a manually operable operating member, and on the basis of a control pressure controlled by a pressure control actuator according to a control amount, and further including an actuator control device including a final-control-value determining portion operable to determine a final value of the control amount, which is used to control the pressure control actuator, and wherein the final-control-value determining portion determines the final value on the basis of at least two provisional control values selected from (a) at least one first provisional control amount each determined by at least one physical quantity including at least one of (i) an operating-state value representative of an operating state of the operating member and (ii) the output pressure, and (b) at least one secon

Abstract: When the increasing gradient of the operating power is larger than a predetermined gradient, if a master pressure PM2 corresponding to a second predetermined operating power F2 is larger than a second predetermined fluid pressure Pth2, a servo function failure in the brake operation is determined; if it is smaller than the second predetermined fluid pressure Pth2, fluid leakage failure (S23, S26, S27) is determined. Furthermore, if the master pressure PM0 corresponding to the first predetermined operating power F0 is larger than a first predetermined fluid pressure Pth1, small amount fluid leakage failure is determined; if it is smaller than the first predetermined fluid pressure Pth1, large amount fluid leakage failure (S28, S29, S30) is determined.

Abstract: A vehicle braking pressure source device including (a) a master cylinder having a pressurizing piston cooperating with a cylinder housing to define a pressurizing chamber and a back-pressure chamber on front and rear sides of the piston, and an input rod which slidably extending through a rear end wall of the cylinder housing such that the piston is advanced by a brake operating force of a brake operating member transmitted thereto through the input rod, to pressurize a working fluid in the pressurizing chamber, (b) a communication passage for communication between the pressurizing and back-pressure chambers, (c) a control valve device disposed in the communication passage for controlling the communication between the pressurizing and back-pressure chambers through the communication passage, and (d) a control valve control device for controlling the control valve device, on the basis of at least one of an operating state of the brake operating member, a running state of the vehicle and a state of a road surfa

Abstract: Apparatus for diagnosing a booster of a vehicle braking system including a brake pedal, a master cylinder for producing a hydraulic pressure on the basis of an output force of the booster produced by boosting of a brake pedal operating force by the booster, and a wheel brake cylinder activated by the hydraulic pressure to brake a vehicle wheel, wherein a determining device is adapted to make a provisional decision as to whether the booster is abnormal or not, on the basis of a relationship between an input quantity and an output quantity of the booster, and a optimizing device is adapted to determine the provisional decision as a final decision or rectifying the provisional decision.

Abstract: A braking system for braking a wheel of an automotive vehicle, including a brake for braking the wheel and an operating device operable to produce an output corresponding to an input thereof, for activating the brake according to the output, and wherein a change of the output of the operating device is delayed with respect to a change of the input depending upon an operating condition of the braking system. The braking system includes a brake-operating-force increasing device operable on the basis of a delay of the change of the output of the operating device with respect to the change of the input, to increase an operating force of the brake to a value which is larger than a value corresponding to the output of the operating device.