The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Jun. 11, 1991
Filed:
Mar. 23, 1990
Hiroshi Sawada, Gotenba, JP;
Tatehito Ueda, Susono, JP;
Kiyoshi Nakanishi, Susono, JP;
Takayuki Demura, Mishima, JP;
Toyota Jidosha Kabushiki Kaisha, Aichi, JP;
Abstract
In an air-fuel ratio feedback control system including at least one air-fuel ratio sensor downstream of a catalyst converter provided in an exhaust gas passage, an actual air-fuel ratio is controlled in accordance with the output of the downstream-side air-fuel ratio sensor. When at least one of the air-fuel ratio feedback control conditions for the downstream-side air-fuel ratio sensor is not satisfied the controlled air-fuel ratio is made an air-fuel ratio by an open loop control, while all the air-fuel ratio feedback control conditions for the downstream-side air-fuel ratio sensor are satisfied the controlled air-fuel ratio is made the stoichometric ratio (.lambda.=1) in accordance with the output of the downstream-side air-fuel ratio sensor. For a period after all the air-fuel ratio feedback control conditions for the downstream-side air-fuel ratio sensor are satisfied, the control by the output of the downstream-side air-fuel ratio sensor is prohibited, but, the controlled air-fuel ratio is made the stoichiometric ratio (.lambda.=1) by an open loop control or by the output of an upstream-side air-fuel ratio sensor.