| 摘要 |
PURPOSE:To detect an air fuel ratio regardless of variance of the characteristics of an oxygen sensor by correcting the output of a sensor part so that the pump current value when the inside of an exhaust pipe is held at a prescribed air fuel ratio is equal to a prescribed reference value. CONSTITUTION:The oxygen sensor 28 is installed in a holder 23. The oxygen sensor 28 consists of a sensor part 26 and a pump part 27. Respective lead wires of the oxygen sensor 28 are connected to a connector 35 through a resistance circuit 41 and further connected a connector 36 to an air fuel ratio detecting means 40. The resistance circuit 41 corrects the output voltage Vs of the sensor part 26 so that the pump current Ip when the inside of the exhaust pipe 33 is held at the prescribed air fuel ratio (e.g. A/F=22) is equal to the prescribed reference value, and outputs the corrected voltage to the air fuel ratio detecting means 40. Consequently, even if the oxygen sensor 28 has variance, the same Ip-A/F characteristics free of variance are obtained and the air fuel ratio is detected accurately. |
