Abstract: An electro-hydraulic braking system for motor vehicles. The system includes a brake pedal and a braking device associated with at least one vehicle wheel which is brought into communication with an electronically controlled valve arrangement in order to apply hydraulic fluid under pressure to the braking device. A fluid pressure accumulator fed by the pump provides a pressurized hydraulic fluid which can be passed to the braking device by way of an electronically controlled valve arrangement in order to apply hydraulic fluid in proportion to the driver braking demand as sensed at the brake pedal in the “brake by wire” mode. A first device within the system provides a level of fluid pressure supply within the electro-hydraulic system whose highest value is less than that sufficient for the maximum possible braking demand level which may be required.

Abstract: A vehicle braking system in which a stored volume of working fluid is used by a brake control system to apply the brakes under the control of an electronic control unit. The stored volume is replenished by pumping additional working fluid using a pump driven by an electric motor. The electric motor is periodically energized. An inferred value is established for the accumulator pressure based on an assessment of the motor response during the periods of energization. The electric motor can be arranged to be energized for short periods at predetermined intervals and the motor response during these periods assessed.