APPARATUS FOR CONTROLLING INTERNAL COMBUSTION ENGINE

摘要

PURPOSE:To enable the calibration of the change of a wide range air/fuel ratio sensor with the elapse of time, by subjecting the relation between an air/fuel ratio and the output of the air/fuel ratio sensor to polynomial approximation with respect to a predetermined air/fuel ratio range. CONSTITUTION:An internal combustion engine has an intake pipe 12 and an exhaust pipe 14 and a fuel feeder 16 like fuel jet valve 24 electrically controlled is provided to the intake pipe 12. A catalyst converter 18 is provided to the exhaust pipe 14 and an air/fuel ratio sensor 20 is provided to the exhaust pipe 14 in order to perform the feedback control of the feeder 16 to detect the air/ fuel ratio of exhaust gas. An electronic control circuit 22 receives the output of the sensor and outputs a control signal to the feeder 16 on the basis of the deviation of an air/fuel ratio to be controlled and a detected air/fuel ratio. The relation between the output of the sensor 20 and the air/fuel ratio is subjected to polynomial approximation and the sensor output at other air/fuel ratio is operated on the basis of the sensor output in an atmospheric state and the output of the sensor 20 is calibrated by the operated output and the sensor output in a theoretical air/fuel ratio.