Automotive hydraulic steering system

A hydraulic control circuit (30) for a vehicle steering system (10) is provided. The hydraulic control circuit (30) is responsive to the rotational position of a steering wheel (32) and controls the actuation of a steering gear assembly (28) in response thereto. The hydraulic circuit (30) includes a first actuator (66) coupled to the vehicle steering wheel (32) and a second hydraulic actuator (68) coupled to the vehicle steering gear assembly (28). The first and second hydraulic actuators (66,68) are coupled together by a pair of fluid conduits (78). Rotation of the steering wheel (32) selectively causes the first actuator (66) to force hydraulic fluid through one of the plurality of fluid conduits (78) to cause the second hydraulic actuator (68) to produce a corresponding output motion. The corresponding output motion is operable for actuating the steering gear assembly (28) in a predetermined direction. The preferred embodiment includes a control system for improved monitoring and control of the hydraulic circuit, as well as an assist pump and compensation valve for gain control.