Control device for internal combustion engine

Abstract

Disclosed is a control device that is used for an internal combustion engine and capable of periodically varying an air-fuel ratio while keeping torque generated by the internal combustion engine at a target torque. The control device can periodically vary a target air-fuel ratio and controls a fuel injection amount in accordance with the target air-fuel ratio which periodically varies. Further, the control device sets an air amount control torque in accordance with the target torque and calculates a target air amount for achieving the air amount control torque at a predetermined virtual air-fuel ratio. The control device then provides air amount control in accordance with the target air amount and calculates an air amount that is estimated to be achieved by the air amount control. Eventually, the control device calculates torque that is estimated to be achieved by the estimated air amount at the target air-fuel ratio, and provides ignition timing control so as to compensate for the difference between the estimated torque and the target torque by correcting ignition timing.