| 摘要 |
An electronic control unit executes air-fuel ratio control composed of main feedback correction and sub-feedback correction. The main feedback correction uses an output value of an upstream side sensor in upstream side of a catalyst. The sub-feedback correction uses an output value of a downstream side sensor in downstream side of the catalyst. When there are cylinder-to-cylinder variations in a fuel injection amount of each fuel injection valve, the electronic control unit corrects the fuel injection amount. Each time the degree of the cylinder-to-cylinder variations is lower than or equal to a first predetermined value, the electronic control unit stores the sub-learning value at that point in time as a normal value, and, when the degree of the cylinder-to-cylinder variations is higher than or equal to a second predetermined value, the electronic control unit changes the sub-learning value to the stored normal value. |
| 主权项 |
1. A control apparatus for an internal combustion engine, the control apparatus comprising:
fuel injection valves configured to inject fuel; a catalyst that is provided in an exhaust passage, the catalyst being configured to purify gas that is emitted from the internal combustion engine; an upstream-side sensor that is arranged upstream of the catalyst, the upstream-side sensor being configured to output an output value corresponding to an actual air-fuel ratio of gas that is emitted from the internal combustion engine; a downstream-side sensor that is arranged downstream of the catalyst, the downstream-side sensor being configured to output an output value corresponding to an actual air-fuel ratio of gas that is emitted from the catalyst; and an electronic control unit configured to:
(i) execute air-fuel ratio control including main feedback correction and sub-feedback correction, the main feedback correction being correction for a fuel injection amount that is injected from the fuel injection valves such that the output value of the upstream-side sensor becomes an output value corresponding to a target air-fuel ratio, the sub-feedback correction being correction for the fuel injection amount that is corrected through the main feedback correction such that the output value of the downstream-side sensor becomes an output value corresponding to the target air-fuel ratio, a sub-correction value including a learning value that compensates for a steady deviation between the output value of the downstream-side sensor and the output value corresponding to the target air-fuel ratio,(ii) when there are cylinder-to-cylinder variations in the fuel injection amount that is injected from the fuel injection valves, execute a process of correcting the fuel injection amount that is corrected in the air-fuel ratio control,(iii) each time the electronic control unit determines that a degree of the cylinder-to-cylinder variations is lower than or equal to a first predetermined value, store the learning value at that point in time as a normal value, and(iv) when the degree of the cylinder-to-cylinder variations is higher than or equal to a second predetermined value, change the learning value at that point in time to the normal value. |
