| 摘要 |
PURPOSE:To make such air-fuel ratio control as being highly accurate and excellent in reliability attainable, by installing both of an inclined O2 sensor having an incremental output characteristic at the rarefied side rather than a theoretical air-fuel ratio in regard to the air-fuel mixture and an on-off type O2 sensor which performs on-off operation at a position in close vicinity to the theoretical air-fuel ratio. CONSTITUTION:An inclined O2 sensor 6 having an incremental output characteristic at the rarefied side rather than a theoretical air-fuel ratio in regard to the air-fuel mixture and an on-off type O2 sensor 5 performing on-off operation at a position in close vicinity to the theoretical air-fuel ratio both are installed in an exhaust passage 4 installed in a ternary catalyzer 7 of an engine 1. These outputs are inputted into a computer 9 together with each output of other various sensors 8. Hereat, a fuel injection quantity is regulated according to the output of the inclined O2 sensor 6, and the air-fuel ratio is thus controlled, while the output of the on-off type O2 sensor 5 is set down to a reference signal whereby the output of the inclined O2 sensor 5 is compensated. And, in conformity with this compensated output of the inclined O2 sensor 6, air-fuel ratio control takes place. |
