Individual cylinder air-fuel ratio control device of internal combustion engine

An individual cylinder air-fuel ratio control device of an internal combustion engine comprising:

• an air-fuel ratio sensor that is provided in an exhaust gas collection part, through which an exhaust gas of an individual cylinder of the internal combustion engine flows together, and that senses an air-fuel ratio of the exhaust gas;
• an air-fuel ratio sensing timing setting part setting an air-fuel ratio sensing timing of the individual cylinder according to at least one of a load and a rotation speed of the internal combustion engine;
• an individual cylinder air-fuel ratio estimation part estimating an air-fuel ratio of the individual cylinder on the basis of a sensed value of the air-fuel ratio sensor, which is sensed at each air-fuel ratio sensing timing of the individual cylinder;
• and
• an individual cylinder air-fuel ratio control part controlling the air-fuel ratio of the individual cylinder on the basis of an estimated air-fuel ratio of the individual cylinder,
• wherein the air-fuel ratio sensing timing setting part corrects the air-fuel ratio sensing timing according to an operation condition of a factor by which an exhaust flow rate of the internal combustion engine is changed.