AIR FUEL RATIO CONTROL DEVICE FOR INTERNAL COMBUSTION ENGINE

摘要

PROBLEM TO BE SOLVED: To provide an air fuel ratio control device for an internal combustion engine capable of controlling air fuel ratio optimally and demonstrate good purification performance without receiving influence of individual difference of O2sensor in a downstream side of a catalyst and deterioration of the catalyst.

SOLUTION: Model distribution width ΔA/F0 is established as a changing status of air fuel ration in which purifying performance of the catalyst can be demonstrated at maximum and distribution width ΔA/F is calculated from air fuel ratio frequency distribution. F/B gain based on O2sensor output is reduced when distribution width ΔA/F is larger than the model distribution width ΔA/F0 and F/B gain is increased when distribution width ΔA/F is the model distribution width ΔA/F0 or less. Consequently, distribution width ΔA/F is always controlled near the model distribution width ΔA/F0.

COPYRIGHT: (C)2006,JPO&NCIPI