Patent ID: 6498973
Filing Date: 2002-12-24
Classification: E02F,F15B

Abstract:
A valve control system for a work vehicle having a plurality of actuators coupled to a plurality of mechanical devices to move the devices, the vehicle having an internal combustion engine coupled to at least one hydraulic pump such that there is a total or maximum flow rate available from the at least one pump to be provided to the actuators to move the mechanical devices, the system comprising:a. a first operator input device that provides a first signal indicative of a degree of deflection of the first device; b. a second operator input device that provides a second signal indicative of a degree of deflection of the second device; c. a first proportional flow control valve responsive to a first valve signal and configured to provide a first hydraulic flow at a flow rate proportional to the first valve signal, the first valve being fluidly coupled to a source of hydraulic fluid flow providing the maximum available flow rate; d. a first hydraulic actuator coupled to the first valve and responsive to the first hydraulic flow; e. a second proportional flow control valve responsive to a second valve signal and configured to provide a second hydraulic flow at a flow rate proportional to the second valve signal, the second valve being fluidly coupled to the source of hydraulic fluid flow to providing the maximum available flow rate; f. a second hydraulic actuator coupled to the second valve and responsive to the second hydraulic flow; g. a third proportional flow control valve responsive to a third valve signal and configured to provide a third hydraulic flow at a flow rate proportional to the third valve signal; h. a third hydraulic actuator coupled to the third valve and responsive to the third hydraulic flow; i. at least one valve controller circuit coupled to the first and second operator input devices and configured to: i. retrieve a value indicative of a maximum available hydraulic fluid flow rate, ii. subtract a value indicative of the third valve flow rate from the maximum flow rate value to leave a value indicative of a remaining available flow rate, iii. proportionately scale values indicative of the first and second flow rates such that their sum is less than the remaining available flow rate, and iv. convert the first, second and third values into valve control signals and apply them to the first, second and third hydraulic actuators.