Patent ID: 7273040

Claim:
An air-fuel ratio control apparatus for an internal combustion engine, comprising: an air-fuel ratio sensor to detect an air-fuel ratio of the internal combustion engine having a fuel injection unit; an air-fuel ratio feedback control unit that has a calculation unit to calculate a fuel injection amount of the fuel injection unit to make a detection value of the air-fuel ratio sensor coincident with a previously given target air-fuel ratio and controls the fuel injection unit based on the fuel injection amount; a start-up completion judgment unit to judge whether the internal combustion engine is in a state where start-up has been completed; an engine condition judgment unit to judge whether the internal combustion engine enters a normal condition after the start-up has been completed; and an upper/lower limit clipping unit that limits a maximum output of the calculation unit to an arbitrary first output range until the time when the engine condition judgment unit judges that the internal combustion engine enters the normal condition from the time when the start-up completion judgment unit judges that the start-up has been completed.