AIR-FUEL RATIO CONTROLLER FOR ENGINE

摘要

PURPOSE:To make air-fuel ratio control done by a closed loop system performable speedily but with high accuracy, by installing an inclined O2 sensor which has an incremental output characteritic at the rarefied side rather than a theoretical air-fuel ratio in regard to the air-fuel mixture. CONSTITUTION:An inclined O2 sensor 5 having an incremental output characteristic at the rarefied side rather than a theoretical air-fuel ratio in regard to the air-fuel mixture supplied is installed in an exhaust passage 4 installed in a ternary catalyzer 6 of an engine 1, and the output is inputted into a computer 9 together with each output of an air quantity sensor 7 and a knock sensor 8. The computer 9 is provided with an air-fuel ratio control device to control the air- fuel ratio in regulating the fuel injection quantity according to the output of the inclined O2 sensor 5. At this time, a memory device to store a fuel quantity variation corresponding to a difference between the setting air-fuel ratio and such an air-fuel ratio as being detected by the inclined O2 sensor 5 is installed in the air-fuel ratio control device. And, the fuel injection quantity is controlled in accordance with the fuel quantity variation read out of the memory device on the basis of the output of the inclined O2 sensor 5.