摘要 |
An simplified structure of an air-fuel ratio control system for an internal combustion engine includes an upstream and a downstream catalytic device installed in an exhaust pipe of the engine and a first, a second, and a third air-fuel ratio sensor installed in upstream or downstream side of the exhaust pipe. The system also includes a first feedback controller working to bring a value of the air-fuel ratio, as measured by the first air-fuel ratio sensor, into agreement with a target one and a second feedback controller working to sample values of the air-fuel ratios, as measured by the second and third air-fuel ratio sensors, to correct a predetermined controlled parameter in the feedback control of the first feedback controller. |