CONTROLLER AND CONTROL METHOD FOR ENGINE

An engine includes water injection valves that inject water to intake ports connected to a cylinder. A controller for the engine is configured to selectively execute, for each of the intake ports, a synchronous injection that causes the water injection valve to inject water only during a valve opening period of the intake valve and an asynchronous injection that causes the water injection valve to inject water during a valve closing period of the intake valve. The controller is configured to perform, when executing a synchronous/asynchronous concurrent injection in which the intake ports includes an intake port in which the synchronous injection is executed and an intake port in which the asynchronous injection is executed, a switching process of switching the intake port in which the asynchronous injection is executed.