Controller and control method for internal combustion engine

A controller for an internal combustion engine, wherein

• the internal combustion engine includes
• a fuel injection valve, which injects fuel,
• an ignition device, which performs spark discharge in a cylinder, and
• a three-way catalyst provided in an exhaust passage,
• the internal combustion engine is configured to ignite air-fuel mixture containing fuel injected from the fuel injection valve by spark discharge of the ignition device to burn the air-fuel mixture in the cylinder, and
• the controller includes circuitry that is configured to:
• when stopping combustion in the cylinder under a situation in which a crankshaft of the internal combustion engine is rotating, select and execute one of a fuel cutoff process of stopping fuel injection of the fuel injection valve and a fuel introduction process of injecting fuel from the fuel injection valve and introducing the fuel from inside the cylinder to the exhaust passage without burning the fuel;
• and
• execute a storing process of executing the fuel cutoff process to store oxygen in the three-way catalyst before starting the fuel introduction process.

A control method for an internal combustion engine, wherein

• the internal combustion engine includes
• a fuel injection valve, which injects fuel,
• an ignition device, which performs spark discharge in a cylinder, and
• a three-way catalyst provided in an exhaust passage,
• the internal combustion engine is configured to ignite air-fuel mixture containing fuel injected from the fuel injection valve by spark discharge of the ignition device to burn the air-fuel mixture in the cylinder, and
• the control method comprises:
• when stopping combustion in the cylinder under a situation in which a crankshaft of the internal combustion engine is rotating, selecting and executing one of a fuel cutoff process of stopping fuel injection of the fuel injection valve and a fuel introduction process of injecting fuel from the fuel injection valve and introducing the fuel from inside the cylinder to the exhaust passage without burning the fuel;
• and
• executing a storing process of executing the fuel cutoff process to store oxygen in the three-way catalyst before starting the fuel introduction process.