US Patent 9605414 Working vehicle and control method therefor

A transmission requirement setting unit sets a required traction force in a work vehicle based on an accelerator operation amount. A work implement requirement setting unit sets a required flow rate based on a work implement operation amount. An engine requirement setting unit determines the horsepower required based on the horsepower required by the transmission set based on the required traction force and the horsepower required by the work implement set based on the required flow rate. A required throttle setting unit determines a commanded throttle value based on the horsepower required. A pump displacement setting unit sets a target displacement for the hydraulic pump based on the required flow rate. The work implement requirement setting unit sets an upper limit for the required flow rate to a prescribed flow rate limit value when the discharge pressure of the hydraulic pump is at or above a prescribed pressure threshold.