Patent ID: 9463780
Filing Date: 2016-10-11
CPC Classification: B60T

Claim Text:
1. A vehicle braking system comprising: a master cylinder configured to receive an input from a brake pedal, the master cylinder having an outlet for a primary circuit including at least one wheel cylinder operable to provide a braking force on a wheel when supplied with pressurized hydraulic fluid, and an outlet for a secondary circuit including at least one wheel cylinder operable to provide a braking force on a wheel when supplied with pressurized hydraulic fluid; a pressure sensor operable to detect an actual, non-boosted driver demand pressure generated at one of the master cylinder outputs from depression of the brake pedal; at least one pump provided in each of the primary circuit and the secondary circuit, the at least one pump defining a pressure side and a suction side of each of the respective primary and secondary circuits; an inlet valve positioned adjacent each wheel cylinder on the pressure side of each of the primary circuit and the secondary circuit; an outlet valve positioned adjacent each wheel cylinder on the suction side of each of the primary circuit and the secondary circuit; a normally open isolation valve positioned between each master cylinder output and the pressure side of the respective primary circuit and the secondary circuit, each isolation valve being movable between an open position that allows fluid communication and a closed position that blocks fluid communication; a pedal feel simulator configured to receive hydraulic fluid from the master cylinder to provide a reaction force to the brake pedal when the isolation valves of the primary and secondary circuits are closed; at least one motor operable to drive the pumps of the primary and secondary circuits to generate hydraulic fluid pressure in the pressure side for supplying to the respective wheel cylinders through the respective inlet valves; a normally closed apply pressure control valve positioned in each of the primary circuit and the secondary circuit between the pressure side and the suction side of the respective circuit, each apply pressure control valve being movable between a closed position in which the full hydraulic fluid pressure at the pressure side is provided to the respective inlet valve and an open position in which the pressure provided to the respective inlet valve is reduced in comparison to that at the pressure side; and a controller operable to receive a signal from the pressure sensor and generate corresponding control signals for the at least one motor and the apply pressure control valves of each of the primary and secondary circuits to produce a hydraulic fluid pressure in the pressure side of each of the primary and secondary circuits equal to the sensed driver demand pressure plus a predetermined boost factor, the actual pressure at each wheel cylinder being configured for individual manipulation by selective opening and closing of the associated inlet and outlet valves.