| 摘要 |
PURPOSE:To stabilize idle running by gradually increasing the value of a learning item when said value of the learning item at the time of idle running is below a certan value, with the output of an O2 sensor indicating a lean condition, while an air-fuel ratio feedback correction factor being above a certain value. CONSTITUTION:On detecting an idling condition through a throttle switch 6, a control circuit 30 which is constructed with microcomputers, judges whether an air-fuel ratio feedback correction factor FAF is above a certain value. And, only when the FAF is above a certain value, it judges whether the output of an O2 sensor 34 indicates a lean condition, i.e., an air-fuel signal is at a low level and, when a lean condition is indicated, it further judges whether the value of a learning item taug at the time of idling is below a certain value, e.g., a negative value. And, only when the value of the taug is below a certain value, this value of the taug is increased by a certain quantity X at each execution of a main routine, to correct the value so as to gradually approach a reference value. Thereby, an erroneously learned value which is learned under an unusual condition can be corrected, stabilizing the idle running. |
