Abstract: A vehicle electro-hydraulic braking system of the type which can operate in a brake-by-wire mode wherein hydraulic pressure is applied to brake actuators (16a, 16b) at the vehicle wheels in proportion to the driver's braking demand (DD) as sensed electronically at a brake pedal (12), wherein the pressure demand (RBD) for the rear brake actuators (16b) is arranged to be delayed until at least one or two conditions has been fulfilled, namely (a) the pressure of at least one front brake actuator (16a) has reached a predetermined pressure (Pmin), and/or (b) a delay threshold (Tmax) of a predetermined level has been exceeded and/or wherein delivery to the fluid to the rearbrake actuators (16b) is limited to a predetermined value that is relatively low with respect to that for the front brakes.

Abstract: A method of detection and identification of pressure sensor faults in an electro-hydraulic braking system of the type comprising a brake pedal, respective braking devices connected to the vehicle wheels and which communicate with electronically controlled proportional control valves in order to apply hydraulic fluid under pressure to the braking devices, respective pressure sensors for measuring the hydraulic pressures at the individual braking devices, a hydraulic pump driven by an electric motor, a high pressure hydraulic pressure accumulator fed by the pump for the provision of hydraulic fluid under pressure which can be passed to the braking devices via the proportional control valves in order to apply hydraulic fluid under pressure to the braking devices in proportion to the driver's braking demand as sensed at the brake pedal, and a supply pressure sensor for monitoring the hydraulic pressure supplied to the electronically controlled proportional control valves.

Abstract: A method of detection and identification of pressure sensor faults in an electro-hydraulic braking system of the type comprising a brake pedal, respective braking devices connected to the vehicle wheels and which communicate with electronically controlled proportional control valves in order to apply hydraulic fluid under pressure to the braking devices, respective pressure sensors for measuring the hydraulic pressures at the individual braking devices, a hydraulic pump driven by an electric motor, a high pressure hydraulic pressure accumulator fed by the pump for the provision of hydraulic fluid under pressure which can be passed to the braking devices via the proportional control valves in order to apply hydraulic fluid under pressure to the braking devices in proportion to the driver's braking demand as sensed at the brake pedal, and a supply pressure sensor for monitoring the hydraulic pressure supplied to the electronically controlled proportional control valves.

Abstract: A method of detection and identification of pressure sensor faults in an electro-hydraulic braking system of the type comprising a brake pedal, respective braking devices connected to the vehicle wheels and which communicate with electronically controlled proportional control valves in order to apply hydraulic fluid under pressure to the braking devices, respective pressure sensors for measuring the hydraulic pressures at the individual braking devices, a hydraulic pump driven by an electric motor, a high pressure hydraulic pressure accumulator fed by the pump for the provision of hydraulic fluid under pressure which can be passed to the braking devices via the proportional control valves in order to apply hydraulic fluid under pressure to the braking devices in proportion to the driver's braking demand as sensed at the brake pedal, and a supply pressure sensor for monitoring the hydraulic pressure supplied to the electronically controlled proportional control valves.

Abstract: A vehicle hydraulic braking system of the brake-by-wire type is disclosed in which proportional solenoid-operated valves (12, 13) are adapted to control the pressure in wheel brake actuators of the brakes (8, 9) on a single axle of a vehicle, and a balance valve (20) is provided to enable individual hydraulic brake circuits to be hydraulically connected so that the pressure applied to each brake is guaranteed to be substantially the same, a first one (13) of the proportional valves (12, 13) is adapted to be isolated so that the hydraulic circuit is fed by a second, single, proportional valve (12). Applying both brakes under the control of a single proportional valve ensures that any fluid leakages are balanced since substantially equal brake-applying pressures are generated.

Abstract: An anti-skid braking system for wheeled vehicles having fluid actuated brakes associated with the vehicle wheels, has speed sensors associated with the vehicle wheels, a control device responsive to speed signals from the speed sensors to actuate a pressure dump device to periodically release the fluid pressure applied to the brake of any wheel which is determined to be about to lock and to later re-apply the actuating pressure to that brake when the tendency of that wheel to lock has reduced, pulsing of the pressure dump device at intervals during the pressure re-apply phase to cause a repeated interruption to the re-application of pressure to that brake. The pulse timing of the pulsing of the pressure dump device is controlled by the occurrence of wheel angular deceleration being determined to be equal to or in excess of a predetermined threshold value, the magnitude of which is dependent upon events from the previous anti-lock braking cycle.

Abstract: An anti-skid braking system for wheeled vehicles having fluid actuated brakes associated with the vehicle wheels. The anti-skid braking system includes speed sensors associated with the vehicle wheels, a scanning control device response to speed signals from the speed sensors to actuate a pressure dump device to periodically release the fluid pressure applied to the brake of any wheel which is determined, by detection of a predetermined level of relative slip between that wheel and the road surface to be about to lock. Later, the system, by detection, can re-apply the actuating pressure to that brake when the tendency of that wheel to lock has been reduced.

Abstract: In a control system, for instance forming part of a vehicle anti-lock brake system, a plurality of control processors provides similar or identical control signals of the system in response to a shared transducer input. An independent data correlation processor compares data generated in the control processors for correlation and, in the absence of proper correlation, provides an indication which may be used to disable anti-lock operation of the brake system. In preferred embodiments, a four wheel vehicle with an anti-lock brake system is monitored by dual microprocessors. Each wheel has a speed sensor which supplies an input to each microprocessor. The data correlation processor compares the outputs of the microprocessors for each wheel and sends and alarm or disables the anti-lock brake system if the difference in the microprocessors output is beyond a limit amount.