Patent ID: 6973926

Claim:
An air-fuel ratio control apparatus for an internal combustion engine, comprising: exhaust component concentration detecting means for detecting the concentration of a specific component in an exhaust gas of said internal combustion engine; heating means for heating said exhaust component concentration detecting means; operating condition detecting means for detecting operating conditions of said internal combustion engine; and control means for receiving a concentration detection signal from said exhaust component concentration detecting means and an operating condition detection signal from said operating condition detecting means, to control said heating means based on said operating condition detection signal and also to output an air-fuel ratio feedback control signal based on said concentration detection signal, wherein said control means: smoothes the concentration detection signal from said exhaust component concentration detecting means, to calculate said air-fuel ratio feedback control signal based on said smoothed concentration detection signal; and also judges whether or not a low temperature condition of said exhaust component concentration detecting means is established, and sets a degree of the smoothing to be a normal value when said low temperature condition is not established but to be a value less than said normal value when said low temperature condition is established.