| 摘要 |
PURPOSE:To prevent any erroneous operation by allowing the feedback control to start a certain time after the start of a combustion engine, when an air-fuel ratio is feedback-controlled by means of a sensor which detects the change of an atmospheric oxygen concentration in exhaust gas. CONSTITUTION:In an exhaust tube 22 of an internal combustion engine 21, first and second electrodes 12, 13 are disposed on the surface of an oxygen ion-conductive solid electrolyte 11, and an oxygen sensor 1 is also provided, while this sensor temporarily generates an output according to the difference between the oxygen partial pressure of the first and second electrodes 12, 13 side occuring temporarily when an atmospheric oxygen concentration is varied rapidly. The output of said oxygen sensor 1 is input in an air-fuel ratio feedback circuit 26 and the reset terminal of a flip-flop 21 through a decision circuit 24. A timer (T) is connected to the reset terminal of said flip-flop 21, while this timer sends out an output a certain time after a crank rotation detection sensor 23 sends out its output, and the gate circuit of an air-fuel ratio control circuit 26 is opened and closed. |
