Air to fuel ratio control device

Abstract

An air-fuel ratio control device of an internal combustion engine is provided. The control device includes a learning section, a correction section, and an inhibiting section. When an execution condition is met, the learning section learns, as a deviation amount learned value, a constant deviation amount between a correction amount and its reference value in different manners between a case in which the lift amount of the intake valve is in a first lift amount region used only when the execution condition is not met and a case in which the lift amount is in a second lift amount region used only when the execution condition is met. The learning section computes and stores the relationship between the deviation amount and the lift amount based on the deviation amount learned value. A correction section computes the deviation amount correction value from the stored relationship based on the lift amount, and corrects the fuel injection amount command value using the deviation amount correction value. When there is no record of completing learning of the deviation amount when the lift amount is in the first lift amount region, an inhibiting section inhibits the lift amount from being shifted from the first lift amount region to other lift amount region.