| 摘要 |
PURPOSE:To prevent the air-fuel mixture from becoming over-ruch, by setting the value of feedback factor alpha for stopping feedback control of the air-fuel ratio at the time of fuel cut at a specific value in an apparatus in which judgement is made from the output of an O2-sensor whether the air-fuel mixture is rich or lean and the value alphais detected from the result of the above judgement. CONSTITUTION:In normal operation of an engine, a base injection pulse width Tp is calculated by an arithmetic circuit 3 from the output signals of an air-flow meter 1 and a rotation sensor 2, and a feedback factor alpha is calculated by an alpha-value calculating circuit 7 on the basis of the result of judgement made by an air-fuel ratio judging circuit 6 to which the output of an O2-sensor 5 is furnished. The final injection pulse width Ti is calculated by correcting the above pulse width Tp by an arithmetic circuit 4 on the basis of the value alpha, etc. On the other hand, in case that the conditions of fuel cut are satisfied at the time of deceleration, changeover circuits 11, 13 are switched respectively to the sides of clamping circuits 12, 14 in response to the fuel-cut signal given from a fuel-cut circuit 15 to clamp the value alpha at a center value alphai based on the valve alpha at the time of idling operation, and the final injection pulse width Ti is calculated by use of the value alphai when supply of fuel is recommenced. |
