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:
Nov. 25, 2014
Filed:
Feb. 15, 2013
Denso Corporation, Kariya, JP;
Denso Corporation, Kariya, JP;
Abstract
An emission control system for an engine includes an upstream sensor provided upstream of a catalyst in a flow direction of exhaust gas, a downstream sensor provided downstream of the catalyst to detect an air-fuel ratio so that the air-fuel ratio approaches a target air-fuel ratio in a sub feedback control, a constant current supply portion which changes an output characteristic of the downstream sensor by applying a constant current on a pair of electrodes thereof. A characteristic control portion controls the constant current supply portion in the sub feedback control to advance a timing of lean detection of the downstream sensor when the air-fuel ratio is richer than the target air-fuel ratio, and to advance a timing of rich detection of the downstream sensor when the air-fuel ratio is leaner than the target air-fuel ratio.