Controller and control method for internal combustion engine

A control method for an internal combustion engine, the method being performed in a vehicle, the vehicle including:

• an internal combustion engine including cylinders;
• an exhaust passage through which an exhaust gas from the cylinders flows;
• and
• a filter arranged in the exhaust passage to trap particulate matter in exhaust gas, wherein
• the control method comprises:
• executing a first suspending process that, when the vehicle satisfies a predetermined first condition, suspends combustion of air-fuel mixture in a specific one of the cylinders;
• executing a second suspending process that, when the vehicle satisfies a predetermined second condition, suspends combustion of air-fuel mixture in all the cylinders, the second condition being different from the first condition;
• during execution of the first suspending process or the second suspending process, obtaining an integrated value of an intake air amount of the internal combustion engine from when the first suspending process or the second suspending process that is being executed was started;
• and
• when the integrated value is greater than or equal to a threshold, stopping the first suspending process or the second suspending process that is being executed, and resuming combustion of air-fuel mixture in all the cylinders,
• the threshold during the execution of the first suspending process is referred to as a first threshold,
• the threshold during the execution of the second suspending process is referred to as a second threshold,
• the first threshold is greater than the second threshold when an amount of particulate matter deposited in the filter is the same.

A controller configured to be employed in a vehicle, the vehicle including:

• an internal combustion engine including cylinders;
• an exhaust passage through which an exhaust gas from the cylinders flows;
• and
• a filter arranged in the exhaust passage to trap particulate matter in exhaust gas,
• the controller comprising:
• circuitry that is configured to control the internal combustion engine, wherein
• the circuitry is configured to execute:
• a first suspending process that, when the vehicle satisfies a predetermined first condition, suspends combustion of air-fuel mixture in a specific one of the cylinders;
• a second suspending process that, when the vehicle satisfies a predetermined second condition, suspends combustion of air-fuel mixture in all the cylinders, the second condition being different from the first condition;
• an integration process that, during execution of the first suspending process or the second suspending process, obtains an integrated value of an intake air amount of the internal combustion engine from when the first suspending process or the second suspending process that is being executed was started;
• and
• a resumption process that, when the integrated value is greater than or equal to a threshold, stops the first suspending process or the second suspending process that is being executed, and resumes combustion of air-fuel mixture in all the cylinders,
• the threshold during the execution of the first suspending process is referred to as a first threshold,
• the threshold during the execution of the second suspending process is referred to as a second threshold,
• the first threshold is greater than the second threshold when an amount of particulate matter deposited in the filter is the same.