Patent ID: 8561751

Claim:
A vehicle steering system comprising: a hydraulic pump configured to provide a source of pressurized hydraulic fluid for use in steering a vehicle; an accumulator configured to hold pressurized hydraulic fluid from the hydraulic pump for use in steering the vehicle in case of need; an accumulator charging circuit comprising a charging valve and a hysteresis valve, the charging valve having a first pilot and a second pilot, the charging valve being configured to selectively allow the hydraulic fluid to flow from the hydraulic pump to the accumulator based on a first fluid pressure applied by the first pilot and a second fluid pressure applied by the second pilot, the hysteresis valve being configured to selectively allow the hydraulic fluid to flow from the charging valve to the first pilot of the charging valve; and a charging bypass circuit configured to allow the hydraulic fluid to flow from the hydraulic pump to a steering control unit and to bypass the accumulator charging circuit; wherein the hydraulic pump supplies hydraulic fluid to the accumulator charging circuit and the charging bypass circuit.