A steering system for a work vehicle having a steerable wheel. The steering system includes a steering input device configured to provide a first steering input and a second steering input to move the steerable wheel. A pilot system is operatively connected to the steering input device and includes a first pilot line operatively connected to the first steering input and a second pilot line operatively connected to the second steering input. A piloted system is operatively connected to the pilot system and includes a direction control valve operatively connected to each of the first and second pilot lines and to a steering cylinder. The steering cylinder is coupled to the steerable wheel. The direction control valve responds to each of the pressure signals of the first and second pilot lines to adjust the position of the steering cylinder which in turn moves the steerable wheel.

A method for operating a motor vehicle, wherein the motor vehicle has a steering system for steering at least one wheel of the motor vehicle by means of a drive. In doing so, it is provided that a time span is determined for at least one countermeasure limiting a hazard to a vehicle occupant upon an at least partial failure of the steering system, within which time span the countermeasure deploys an effect, and that a state variable (T) influencing the operating capacity of the steering system is determined and extrapolated over time and a point in time (t.sub.1) is calculated in which the state variable (T) exceeds a limit value (T.sub.1), wherein the countermeasure is introduced when the point in time (t.sub.1) is less than the time span in the future.

A hydraulic steering arrangement (1) is described comprising a supply port arrangement (P, T) having a pressure port (P) and a tank port (T), a working port arrangement having two working ports (L, R), a main flow path (2) having a main orifice (A.sub.1), at least one further orifice (A.sub.2, A.sub.3, A.sub.4) downstream the main orifice (A.sub.1), and a measuring motor (3), the main flow path (2) being arranged between the pressure port (P) and the working port arrangement (L, R), a return flow path (4) arranged between the working port arrangement (L, R) and the tank port (T), an amplification flow path (6) having an amplification orifice (A.sub.U) and being arranged between the pressure port (P) and the working port arrangement (L, R), and an adjustable pressure source (9) connected to the pressure port (P) and having a load sensing port (18), wherein a main drain orifice (A.sub.md) is connected between the main flow path (2) downstream the main orifice (A.sub.1) and the return flow path (4). It should be possible to operate such a steering arrangement with a dynamic flow. To this end a flow divider (19) connects the load sensing port (18) with the main flow path (2) downstream the main orifice (A.sub.1) and the amplification flow path (6) downstream the amplification orifice (A.sub.U).

A system and method for performing a diagnostic on a hydraulic system in a vehicle while the vehicle is at a standstill. The method includes, by means of an electronic processor, moving a plunger at a constant rate, determining a position of the plunger, receiving a pressure of the hydraulic system from a pressure sensor, comparing the determined position and the measured pressure to a position versus pressure graph, and sending a diagnostic to a diagnostic indicator.

A method for use with a vehicle having one or more subsystems includes receiving vehicle health management (VHM) information via a controller indicative of a state of health of the subsystem. The VHM information is based on prior testing results of the subsystem. The method includes determining a required testing profile using the testing results, applying the testing profile to the subsystem to thereby control a state of the subsystem, and measuring a response of the subsystem to the applied testing profile. The method also includes recording additional testing results in memory of the controller that is indicative of a response of the subsystem to the applied testing profile. The vehicle includes a plurality of subsystems and a controller configured to execute the method.

A method for use with a vehicle having one or more subsystems includes receiving vehicle health management (VHM) information via a controller indicative of a state of health of the subsystem. The VHM information is based on prior testing results of the subsystem. The method includes determining a required testing profile using the testing results, applying the testing profile to the subsystem to thereby control a state of the subsystem, and measuring a response of the subsystem to the applied testing profile. The method also includes recording additional testing results in memory of the controller that is indicative of a response of the subsystem to the applied testing profile. The vehicle includes a plurality of subsystems and a controller configured to execute the method.

A method (300) and control arrangement (210) for controlling a vehicle (100) to freewheel with engine off. The vehicle (100) has an engine (260) for propelling the vehicle (100) and a hydraulic power steering system (400). The hydraulic power steering system (400) comprises a primary power steering pump (270a) arranged to be driven by the engine (260) and a secondary power steering pump (270b). The method (300) includes: determining (301) when to start freewheeling the vehicle (100) with its engine off; and prior to starting the freewheeling of the vehicle (100) with engine off, determining (302) to start the secondary power steering pump (270b).

A method (300) and control arrangement (210) for controlling a vehicle (100) to freewheel with engine off. The vehicle (100) has an engine (260) for propelling the vehicle (100) and a hydraulic power steering system (400). The hydraulic power steering system (400) comprises a primary power steering pump (270a) arranged to be driven by the engine (260) and a secondary power steering pump (270b). The method (300) includes: determining (301) when to start freewheeling the vehicle (100) with its engine off; and prior to starting the freewheeling of the vehicle (100) with engine off, determining (302) to start the secondary power steering pump (270b).

A method for controlling a power steering system of a road vehicle includes: after the road vehicle is started, activating only an EPS subsystem; afterward, activating an EHPS subsystem when a speed of the road vehicle is not higher than a predetermined speed threshold; once the EHPS subsystem is activated, controlling the hydraulic motor of the EHPS subsystem to rotate at a rotational speed lower than a pre-set rotational speed when a torque applied to a steering column is smaller than a predetermined torque threshold.

A method for controlling a power steering system of a road vehicle includes: after the road vehicle is started, activating only an EPS subsystem; afterward, activating an EHPS subsystem when a speed of the road vehicle is not higher than a predetermined speed threshold; once the EHPS subsystem is activated, controlling the hydraulic motor of the EHPS subsystem to rotate at a rotational speed lower than a pre-set rotational speed when a torque applied to a steering column is smaller than a predetermined torque threshold.