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:
May. 04, 1993
Filed:
May. 13, 1992
Nobuaki Kayanuma, Gotenba, JP;
Toyota Jidosha Kabushiki Kaisha, Aichi, JP;
Abstract
An air-fuel ratio control device for an engine having two or more cylinder groups, such as a V-type engine or a horizontally opposed engine, wherein the air-fuel ratio control device controls the air-fuel ratio of cylinder groups in accordance with the output of upstream air-fuel ratio sensors and a downstream air-fuel ratio sensor. The upstream air-fuel ratio sensors are disposed in the individual exhaust passage connected to the respective cylinders upstream of the catalyst converter. The downstream air-fuel ratio sensor is disposed in the common exhaust passage downstream of the catalyst converter. The air-fuel control device usually controls the air-fuel ratios of individual cylinder groups in accordance with the output of the respective upstream air-fuel ratio sensor. When a determination of whether or not the catalyst converter has deteriorated is required, the air-fuel ratio control device controls the air-fuel ratio of all cylinder groups in accordance with the output of either one of upstream air-fuel ratio sensors, whereby the air fuel ratio of the exhaust gas flow into the catalyst converter is changed at a predetermined frequency (period). In this condition, the air-fuel ratio control device determines whether or not the catalyst converter has deteriorated by comparing the outputs of the upstream air-fuel ratio sensor and the downstream air-fuel ratio sensor.