Oxygen sensor output correction apparatus for internal combustion engine

A correction apparatus for correcting an error in an output of an oxygen sensor installed in an exhaust pipe of an internal combustion engine to measure a concentration of oxygen contained in exhaust gas comprising:

• an oxygen concentration-correlating parameter determining circuit that determines a given parameter correlating with an actual concentration of oxygen contained in the exhaust gas which is emitted from the internal combustion engine into the exhaust pipe after start of a fuel cut event in which the engine undergoes a fuel cut;
• an oxygen concentration-corresponding output determining circuit that determines an oxygen concentration-corresponding output based on the given parameter, as determined by said oxygen concentration-correlating parameter determining circuit, the oxygen concentration-corresponding output being a parameter corresponding to an output of the oxygen sensor which is to represent the actual concentration of oxygen;
• and
• a correction factor determining circuit that, when required to enter a correction mode, samples an output of the oxygen sensor during the fuel cut event and determines a correction factor based on the sampled output of the oxygen sensor and the oxygen concentration-corresponding output, as determined by said oxygen concentration-corresponding output determining circuit for use in correcting an output of the oxygen sensor when the engine is undergoing no fuel cut.