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:
Feb. 05, 2008
Filed:
Feb. 17, 2005
Manabu Miura, Zushi, JP;
Manabu Miura, Zushi, JP;
Nissan Motor Co., Ltd., Yokohama-shi, JP;
Abstract
To determine whether an exhaust gas purification catalyst () of an engine () has deteriorated, a characteristic of exhaust gas on an upstream side of the catalyst () is detected, a characteristic of the exhaust gas on a downstream side of the catalyst () is detected, and when the engine () operates at a lean air-fuel ratio, a value expressing a difference in the oxygen concentration on the upstream side and downstream side of the catalyst () (an average excess air ratio difference) is calculated from the two detected values. When the value expressing the difference in the oxygen concentration is smaller than a deterioration determination threshold calculated in accordance with a quantity of state of the catalyst (), the catalyst () is determined to have deteriorated.