Controller and control method for internal combustion engine

A controller for an internal combustion engine, wherein

• the internal combustion engine includes multiple cylinders and an aftertreatment device in an exhaust passage,
• the aftertreatment device includes a catalyst that stores oxygen,
• the controller includes circuitry, the circuitry being configured to execute a temperature increasing process and a scavenging process of the aftertreatment device,
• the temperature increasing process includes:
• a stopping process that stops a combustion operation in a first cylinder of the cylinders;
• and
• a rich combustion process that causes an air-fuel ratio of air-fuel mixture in a second cylinder of the cylinders to be less than a stoichiometric air-fuel ratio, the second cylinder being different from the first cylinder,
• the scavenging process is executed prior to a specific combustion cycle that includes the rich combustion process,
• the scavenging process includes, during one combustion cycle:
• the stopping process;
• and
• a process that causes the air-fuel ratio of the air-fuel mixture in the second cylinder to be greater than or equal to the stoichiometric air-fuel ratio.

A control method for an internal combustion engine, wherein

• the internal combustion engine includes multiple cylinders and an aftertreatment device in an exhaust passage,
• the aftertreatment device includes a catalyst that stores oxygen,
• the control method comprises:
• executing a temperature increasing process of the aftertreatment device;
• and
• executing a scavenging process of the aftertreatment device, the temperature increasing process includes:
• a stopping process that stops a combustion operation in a first cylinder of the cylinders;
• and
• a rich combustion process that causes an air-fuel ratio of air-fuel mixture in a second cylinder of the cylinders to be less than a stoichiometric air-fuel ratio, the second cylinder being different from the first cylinder,
• the scavenging process is executed prior to a specific combustion cycle that includes the rich combustion process, and
• the scavenging process includes, during one combustion cycle:
• the stopping process;
• and
• a process that causes the air-fuel ratio of the air-fuel mixture in the second cylinder to be greater than or equal to the stoichiometric air-fuel ratio.