CONTROL DEVICE FOR AIR-FUEL RATIO

摘要

PURPOSE:To enable control of an air-fuel ratio corresponding to the magnitude of the deviation from a target air-fuel ratio by determining a flush current value as a ratio for the value of the flush current when the inside of an exhaust pipe is under atmospheric air and controlling the air-fuel ratio according to said ratio. CONSTITUTION:Atmospheric air is filled in an exhaust pipe when fuel cut is continued for prescribed time (t). When a fuel cut signal F/C is kept outputted for the time (t) from a means 13 for controlling feedback, a means 14 for generating a holding signal outputs a holding signal SH to a holding means 15. The means 15 holds the Vi when the holding signal SH is inputted thereto as Vio and outputs the same to a standardizing means 16. The means 16 calculates the ratio ViN (ViN=Vi/Vio) of Vi with respect to Vio and outputs the same to the means 13. The means 13 determines a correction factor according to the signal ViN indicating the air-fuel ratio standardized in the above-mentioned way and performs feedback control of the air-fuel ratio.