Controller and control method for wastegate

A method for controlling a wastegate, the wastegate being provided in an exhaust bypass passage that allows exhaust gas to bypass a turbine wheel of an exhaust turbine-type forced-induction device, a required boost pressure being set in accordance with a running state of an engine, wherein the method comprises:

• controlling a drive force of the wastegate to a magnitude that achieves the required boost pressure when the required boost pressure is higher than a preset pressure, and
• controlling the drive force to a magnitude that achieves a higher boost pressure than the required boost pressure when the required boost pressure is less than or equal to the preset pressure.

A non-transitory computer-readable storage medium that stores a program causing a processor to execute a control process for a wastegate, the wastegate being provided in an exhaust bypass passage that allows exhaust gas to bypass a turbine wheel of an exhaust turbine-type forced-induction device, a required boost pressure being set in accordance with a running state of an engine, wherein the control process comprises:

• controlling a drive force of the wastegate to a magnitude that achieves the required boost pressure when the required boost pressure is higher than a preset pressure, and
• controlling the drive force to a magnitude that achieves a higher boost pressure than the required boost pressure when the required boost pressure is less than or equal to the preset pressure.