| 摘要 |
PURPOSE:To stabilize an idle running by setting a lean-correction factor to a constant value during idle running, in a device in which an air-fuel ratio is controlled to the lean side using a lean correction factor determined in accordance with an air intake pipe pressure, etc. under a specified condition. CONSTITUTION:When the engine runs, it is judged in a control circuit 54, as to whether or not the condition where a temperature of cooling water detected by a water-temperature sensor 38 reaches the specified value (for example 75 deg.C) or more, and an air intake pipe pressure detected by a pressure sensor 14 reaches the specified value (for example 450mm.Hg) or more, can be realized, and it is subsequently judged as to whether or not the engine running state is able to lean-control the air-fuel ratio at the time of light-loading after the end of warming up. And when making YES-judgement, it is judged as to whether or not an idle switch 12 is in OFF-position, and the air-fuel ratio is controlled by the lean correction facter determined on the basis of the air intake pipe pressure, etc. when the idle switch 12 opens the off-throttle valve 10. On the other hand, the air-fuel ratio is controlled by setting the lean factor to a constant value during idle running with the switch 12 ON. |
