Abstract: An electronic traction control system for a vehicle having multiple hydraulic driven wheels includes a plurality of digital displacement pumps, a plurality of drive systems having counterbalance valves and motors used to drive wheels, and electronic flow control valves used in association with each drive assembly. Additionally the system has a steering mechanism that is electrically connected to a digital sensor and a proportional sensor that sends signals to a system controller that operates the functioning of the digital displacement hydraulic pumps.

Abstract: A valve assembly (1) operable to allow or prevent the flow of fluid to or from a working chamber of a fluid-operated machine, comprising radially spaced apart inner and outer annular valve seats (8, 15) defining an annular passage therebetween, a valve member comprising a sealing ring (21), and means (3, 7, 26, 25) for moving the valve member axially between a first position in which the sealing ring (21) is in seating engagement with the annular valve seats to close the annular passage to fluid flow therethrough and a second position in which the sealing ring (21) is spaced from the annular valve seats (8, 15) so that the annular passage is open to fluid flow therethrough. The valve assembly further comprises axially spaced apart first and second valve guide means (6) for guiding the valve member during axial movement between its first and second positions.