Controller for internal combustion engine and non-transitory computer-readable storage medium storing program for internal combustion engine

A non-transitory computer-readable storage medium storing a program for an internal combustion engine, the internal combustion engine including an engine main body in which a plurality of cylinders are defined, a plurality of water injection valves respectively provided for the plurality of cylinders and configured to supply water to the plurality of cylinders, an exhaust gas recirculation (EGR) passage configured to draw some of exhaust gas flowing through an exhaust passage into an intake passage as an EGR gas, and an EGR cooler arranged in the EGR passage and configured to cool the EGR gas, wherein

• an amount of condensed water generated in the EGR passage and flowing into one of the plurality of cylinders during a unit period is referred to as an EGR water amount,
• a controller for the internal combustion engine stores information indicating a corresponding relationship between an operation parameter related to an operation state of the internal combustion engine and a water amount parameter related to the EGR water amount for each of the plurality of cylinders,
• when the internal combustion engine is operating, the program causes the controller to:
• execute a first process for each of the plurality of cylinders based on the information, the first process acquiring a target water injection amount of a subject cylinder of the plurality of cylinders by subtracting the EGR water amount of the subject cylinder from a reference water amount that corresponds to the operation state of the internal combustion engine;
• and
• execute a second process that controls the plurality of water injection valves so that the water injection valves each injects the target water injection amount.