Dual sensor type air fuel ratio control system for internal combustion engine

U.S. Patent Number: 5335493

Abstract: A learning or updating function which corrects the feedback control correction factor is included in a dual O.sub.2 sensor type control system. Correction related data which is used to modify in response to the output of an upstream sensor or sensor section, is recorded at memory addresses which corresponding to the sub-sections of an engine operation map. When the output of the upstream sensor changes, a sub-region in which the engine operation fell a time .tau. earlier or in which the engine operation has continuously fallen for the time .tau., is selected and the correction related data which is recorded at the corresponding address, read out, updated based in the output of the second sensor or sensor section and re-recorded at the same address.

Inventors: Uchida; Masaaki (Yokosuka, JP), Matsumoto; Mikio (Yokosuka, JP)

Assignee: Nissan Motor Co., Ltd. (Yokohama, JP)

Application Number: 07/645,975

Issued: 1994-08-09

Expired: 2006-08-09

Classes: 60/274 ; 123/674; 123/691; 60/276; 60/285

Field of search: 60/274,276,285 123/674,691

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