AIR/FUEL RATIO DETECTION DEVICE FOR INTERNAL COMBUSTION ENGINE

摘要

PROBLEM TO BE SOLVED: To carry out a detection of air/fuel ratio with good accuracy by accurately presuming a HC concentration and correcting it based on this not using a HC concentration sensor. SOLUTION: An internal combustion engine is provided with an air/fuel ratio sensor 14 of which an output is varied in proportion corresponding to an exhaust gas concentration of the internal combustion engine; and an air/fuel ratio detection device for detecting an air/fuel ratio based on the output of this air/fuel ratio sensor 14. An operation state of the internal combustion engine is detected and a hydrocarbon concentration at the time of cooling the engine and a hydrocarbon concentration at the time of warming the engine are presumed. The output of the air/fuel ratio sensor 14 is corrected based on a presumed hydrocarbon concentration at the time of cooling/warming the engine selected corresponding to the operation state.