Work vehicle and method for controlling work vehicle

A method for controlling a work vehicle including an engine, a throttle opening degree setting unit for setting a throttle opening degree of the engine, a first hydraulic pump driven by the engine, a travel hydraulic motor driven by hydraulic fluid discharged from the first hydraulic pump, a second hydraulic pump driven by the engine, and a work implement having a bucket and a boom driven by hydraulic fluid discharged from the second hydraulic pump;

• the method comprising:
• determining whether the work vehicle is performing excavation work;
• setting an upper limit of the throttle opening degree in accordance with a determination result as to whether the work vehicle is performing excavation work;
• and
• controlling output of the engine based on the smaller of the throttle opening degree set by the throttle opening degree setting unit and the throttle opening degree set by the setting of the upper limit of the throttle opening degree in accordance with the determination result;
• the setting of the upper limit of the throttle opening degree including setting the upper limit based on throttle upper limit information for specifying the upper limit of the throttle opening degree with respect to vehicle speed, the throttle upper limit information including first throttle upper limit information, second throttle upper limit information for specifying a lower upper limit of the throttle opening degree with respect to the vehicle speed than the first throttle upper limit information, and third throttle upper limit information for specifying a lower upper limit of the throttle opening degree with respect to the vehicle speed than the second throttle upper limit information,
• the setting of the upper limit of the throttle opening degree further including
• setting the upper limit of the throttle opening degree based on the third throttle upper limit information when the determination result indicates that the work vehicle is performing excavation work and when the work implement is not in use,
• setting the upper limit of the throttle opening degree based on the second throttle upper limit information when the determination result indicates that the work vehicle is performing excavation work and when the work implement is in use, and
• setting the upper limit of the throttle opening degree based on the first throttle upper limit information when an angle in a longitudinal direction of the boom, defined so that a value of the angle increases upward, is equal to or greater than a predetermined angle, even when the determination result indicates that the work vehicle is performing excavation work.