| 摘要 |
PURPOSE:To perform accurate theoretical air-fuel ratio control by deciding the air-fuel ratio on the basis of flowing current level if the target air-fuel ratio is lean while through abrupt change of output from O2 sensor if the target air-fuel ratio is at theoretical level. CONSTITUTION:Upon setting of lean air-fuel ratio as target air-fuel ratio by means of an air-fuel ratio setting means 23, lean current LL is fed as flow-in current LS from curent feeding means 12 to O2 sensor 11 to produce voltage signal Vi from current level detecting means 13. Then predetermined level of target air-fuel ratio Vc is subtracted from Vi to obtain a difference DELTAV which is provided to a factor operating means 17 to produce a correction factor (a) thus to control air-fuel ratio. Upon setting of theoretical air-fuel ratio as target level through means 23, constant current I0 is fed from means 12 to sensor 11 to change the output Vs from O2 sensor abruptly at the theoretical air-fuel ratio thus to produce rich or lean signal SR, SL from comparing means 18 and to perform control to accurate theoretical air-fuel ratio. |
