Abstract: When a purge valve opens, a CPU calculates a purge concentration learning value based on an air-fuel ratio detected by an air-fuel ratio sensor. Additionally, under the condition that a temperature increase request of a three-way catalyst is generated, the CPU performs dither control that sets one of a plurality of cylinders as a rich combustion cylinder, which is richer than a theoretical air-fuel ratio, and the remaining cylinders as lean combustion cylinders, which are leaner than the theoretical air-fuel ratio. When the dither control is performed, the CPU forbids the update of the purge concentration learning value.

Abstract: A controller for an internal combustion engine includes processing circuitry configured to execute: a dither control process of operating fuel injection valves to designate at least one of cylinders as a lean combustion cylinder, in which an air-fuel ratio is leaner than a stoichiometric air-fuel ratio, and to designate at least another one of the cylinders as a rich combustion cylinder, in which an air-fuel ratio is richer than the stoichiometric air-fuel ratio; and an idle-time limiting process of causing an absolute value of a difference between the air-fuel ratio in the lean combustion cylinder and the air-fuel ratio in the rich combustion cylinder to be smaller when the internal combustion engine is idling than when the internal combustion engine is not idling.

Abstract: A controller is configured to execute a dither control process of operating fuel injection valves such that at least one of cylinders is a lean combustion cylinder, in which the air-fuel ratio is leaner than the stoichiometric air-fuel ratio, and at least another one of the cylinders is a rich combustion cylinder, in which the air-fuel ratio is richer than the stoichiometric air-fuel ratio, and a limiting process of limiting the dither control process such that the difference in the air-fuel ratio between the cylinders is smaller in a change period, in which a gear ratio of the multi-speed transmission is changed, than in periods except for the change period.

Abstract: A control device for an internal combustion engine includes an electronic control unit configured to determine whether or not cylinder-specific air-fuel ratio processing is being executed in which an air-fuel ratio of at least one of a plurality of cylinders is controlled to be a rich air-fuel ratio and an air-fuel ratio of at least one of the other cylinders is controlled to be a lean air-fuel ratio. The electronic control unit updates a first learning value in which a result of comparison between a knock strength of the internal combustion engine and a first determination value is reflected when the cylinder-specific air-fuel ratio processing is not being executed. The electronic control unit prohibits updating of the first learning value and calculates a target ignition timing of the internal combustion engine based on the first learning value when the cylinder-specific air-fuel ratio processing is being executed.

Abstract: A controller for an internal combustion engine includes processing circuitry. The processing circuitry is configured to execute a dither control process under a condition in which a request for executing a regeneration process of a filter is made. The processing circuitry is further configured to execute a fuel cutting process stopping fuel injection performed by fuel injection valves under a condition in which an accelerator operation amount is zero and a prohibition process prohibiting the fuel cutting process under a condition in which the dither control process is executed.

Abstract: A CPU operates a purge valve to control the amount of fuel vapor that flows into an intake passage from a canister. If there is a requirement for increasing the temperature of a three-way catalyst, the CPU executes dither control in which the air-fuel ratio of one of cylinders #1 to #4 is made richer than the stoichiometric air-fuel ratio, and the air-fuel ratio of the remaining cylinders is made leaner than the stoichiometric air-fuel ratio. The CPU executes the dither control and performs feedforward correction of the distribution variation of the fuel vapor to the cylinders #1 to #4 if the amount of fuel vapor from the canister to the intake passage is greater than zero.

Abstract: A controller for an internal combustion engine includes processing circuitry configured to execute: a dither control process of operating fuel injection valves to designate at least one of cylinders as a lean combustion cylinder, in which an air-fuel ratio is leaner than a stoichiometric air-fuel ratio, and to designate at least another one of the cylinders as a rich combustion cylinder, in which an air-fuel ratio is richer than the stoichiometric air-fuel ratio; and an idle-time limiting process of causing an absolute value of a difference between the air-fuel ratio in the lean combustion cylinder and the air-fuel ratio in the rich combustion cylinder to be smaller when the internal combustion engine is idling than when the internal combustion engine is not idling.

Abstract: When a purge valve opens, a CPU calculates a purge concentration learning value based on an air-fuel ratio detected by an air-fuel ratio sensor. Additionally, under the condition that a temperature increase request of a three-way catalyst is generated, the CPU performs dither control that sets one of a plurality of cylinders as a rich combustion cylinder, which is richer than a theoretical air-fuel ratio, and the remaining cylinders as lean combustion cylinders, which are leaner than the theoretical air-fuel ratio. When the dither control is performed, the CPU forbids the update of the purge concentration learning value.

Abstract: A controller is configured to execute a dither control process of operating fuel injection valves such that at least one of cylinders is a lean combustion cylinder, in which the air-fuel ratio is leaner than the stoichiometric air-fuel ratio, and at least another one of the cylinders is a rich combustion cylinder, in which the air-fuel ratio is richer than the stoichiometric air-fuel ratio, and a limiting process of limiting the dither control process such that the difference in the air-fuel ratio between the cylinders is smaller in a change period, in which a gear ratio of the multi-speed transmission is changed, than in periods except for the change period.

Abstract: A control device for an internal combustion engine includes an electronic control unit configured to determine whether or not cylinder-specific air-fuel ratio processing is being executed in which an air-fuel ratio of at least one of a plurality of cylinders is controlled to be a rich air-fuel ratio and an air-fuel ratio of at least one of the other cylinders is controlled to be a lean air-fuel ratio. The electronic control unit updates a first learning value in which a result of comparison between a knock strength of the internal combustion engine and a first determination value is reflected when the cylinder-specific air-fuel ratio processing is not being executed. The electronic control unit prohibits updating of the first learning value and calculates a target ignition timing of the internal combustion engine based on the first learning value when the cylinder-specific air-fuel ratio processing is being executed.