Patent ID: 8417413

Claim:
An oxygen sensor control apparatus which includes first storage means for storing a correction coefficient used for calibrating a relation between an output value of an oxygen sensor mounted to an exhaust pipe of an internal combustion engine and oxygen concentration of exhaust gas flowing through the exhaust pipe and which detects the oxygen concentration of the exhaust gas using the correction coefficient stored in the first storage means and the output value of the oxygen sensor, the oxygen sensor control apparatus comprising: output value obtaining means for obtaining the output value of the oxygen sensor; representative value determination means for determining a representative value from at least one output value obtained by the output value obtaining means in a fuel cut period during which supply of fuel to the internal combustion engine is stopped, the representative value representing output values in the fuel cut period; first memorization control means for storing in second storage means the representative value in the fuel cut period determined by the representative value determination means; first range judgment means for judging whether or not a latest representative value, which is the latest representative value stored in the second storage means by the first memorization control means, falls outside a predetermined first range; second range judgment means for judging whether or not the latest representative value falls outside a predetermined second range, which contains the first range and is wider than the first range; first representative value judging means for judging whether or not a first judgment count has reached a first number of times equal to or greater than two times, the first judgment count representing a number of times the latest representative value is continuously judged by the first range judgment means to fall outside the first range and the latest representative value is continuously judged by the second range judgment means not to fall outside the second range; first computation means for computing a new value of the correction coefficient when the first representative value judging means judges that the first judgment count has reached the first number of times; second representative value judging means for judging whether or not a second judgment count has reached a second number of times smaller than the first number of times, the second judgment count representing a number of times the latest representative value is continuously judged by the second range judgment means to fall outside the second range; second computation means for computing a new value of the correction coefficient when the second representative value judging means judges that the second judgment count has reached the second number of times; and second memorization control means for storing in the first storage means the new value of the correction coefficient computed by the first computation means or the second computation means.