Controller for internal combustion engine and method for controlling internal combustion engine

A controller for an internal combustion engine of a spark ignition type, wherein the internal combustion engine includes a fuel injection valve configured to inject fuel and a three-way catalyst provided in an exhaust passage, and the internal combustion engine is configured to burn an air-fuel mixture containing fuel injected from the fuel injection valve in a cylinder,

• the controller comprising circuitry, wherein the circuitry is configured to perform
• selectively executing one of a fuel cut process and a fuel feeding process when stopping combustion in the cylinder in a situation in which a crankshaft of the internal combustion engine is rotating, the fuel cut process including stopping fuel injection of the fuel injection valve, and the fuel feeding process including injecting fuel from the fuel injection valve and discharging the fuel in an unburned state from the cylinder to the exhaust passage,
• executing an enrichment process that controls the fuel injection valve when combustion is resumed in the cylinder in which the combustion has been stopped, so that an air-fuel ratio is set to be richer than a stoichiometric air-fuel ratio, and
• executing the enrichment process when resuming combustion in the cylinder in which the combustion has been stopped, so that in a case in which the fuel feeding process is executed in a period during which combustion is stopped in the cylinder, a decrease amount of an oxygen storage amount of the three-way catalyst is less than in a case in which the fuel feeding process is not executed in the period during which combustion is stopped in the cylinder.

A method for controlling an internal combustion engine of a spark ignition type, wherein the internal combustion engine includes a fuel injection valve configured to inject fuel and a three-way catalyst provided in an exhaust passage, and the internal combustion engine is configured to burn an air-fuel mixture containing fuel injected from the fuel injection valve in a cylinder, the method comprising:

• selectively executing one of a fuel cut process and a fuel feeding process when stopping combustion in the cylinder in a situation in which a crankshaft of the internal combustion engine is rotating, the fuel cut process including stopping fuel injection of the fuel injection valve, and the fuel feeding process including injecting fuel from the fuel injection valve and discharging the fuel in an unburned state from the cylinder to the exhaust passage;
• executing an enrichment process that controls the fuel injection valve when combustion is resumed in the cylinder in which the combustion has been stopped, so that an air-fuel ratio is set to be richer than a stoichiometric air-fuel ratio;
• and
• setting a decrease amount of an oxygen storage amount of the three-way catalyst corresponding to the enrichment process when executing the enrichment process.