| 摘要 |
PURPOSE:To enhance the accuracy of air-fuel ratio control, by providing a judgment means for detecting whether a high air-fuel ratio has lasted over a prescribed time or not, and a gas feed means for supplying a gas of more than a prescribed oxygen concentration into an exhaust pipe. CONSTITUTION:The air-fuel ratio is calculated by an air-fuel ratio detection means b on the basis of the output of an oxygen sensor (a). A control signal for regulating intake air or fuel is sent out from a control means (c). It is found out by a judgment means (e) whether a high air-fuel ratio has lasted over a prescribed time or not. When it is found out by the means (e) that the high air-fuel has lasted over the prescribed time, a feed signal is sent out. A gas of more than a prescribed oxygen concentration is supplied into an exhaust pipe by a gas feed means (f) in response to the feed signal applied thereto, so as to burn up an unnecessary substance clinging to the oxygen sensor (a). The drop in the accuracy of air-fuel ratio detection is thus prevented to enhance the accuracy of air-fuel ratio control. |
