| 摘要 |
<p>PURPOSE: To prevent deterioration of accuracy of air-fuel ratio controlling by providing plural O2 sensor, detecting activation of a second O2 sensor based on time passage from starting of an engine, and performing air-fuel ratio feedback control by means of a first O2 sensor until the second O2 sensor is activated. CONSTITUTION: A linear O2 sensor 16 is arranged on an upstream side of a catalytic converter 15 inside an exhaust passage 3, whileλO2 sensor 17 is arranged on a downstream side. Output signals therefrom are input to a control unit 18 together with output signals from a crank angle sensor 19, an air-flow meter 11 and the like, for controlling a fuel injection valve 8 and the controlling and air-fuel ratio. After starting an engine, air-fuel ratio feedback control is performed from an output of theλO2 sensor 17 provided in order to detect deterioration of the catalytic converter 15 and failure of the linear O2 sensor 16, until the linear O2 sensor 16 its activated, in place thereof. After activating the linear O2 sensor, control is switched to that based on the linear O2 sensor.</p> |
