| 摘要 |
PURPOSE:To precisely obtain a correcting factor of an air-fuel ratio, by arranging such that an air-fuel ratio sensor adapted to output a discrepancy from a preset air-fuel ratio is used to compare the preset air-fuel ratio as stored at every operating point of an engine with a value as provided after passage of a variation delaying time of sensor signal. CONSTITUTION:When an engine load varies from theta1 to theta2, an air-fuel ratio control device functions to vary a preset air-fuel ratio to a ratio suitable for an engine load as shown by b, and control a flow of electric current into an air- fuel ratio sensor so as to vary it into c after passage of variation delaying time T, the flow of electric current corresponding with a discrepancy from a preset air-fuel ratio. As the air-fuel ratio control device varies with passage of time, the air-fuel ratio sensor varies its output sharply after passage of delaying time T as shown by (d). The control device continues to renew its air-fuel ratio correcting factor by a method wherein an air-fuel ratio as detected at a certain point is compared with a preset value as stored as it may be before the passage of variation delaying time T, and thereby obtaining a discrepancy as a result of variation with passage of time. |
