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:
Dec. 28, 2004
Filed:
Dec. 31, 2002
Chul-Soo Yook, Suwon, KR;
Hyundai Motor Company, Seoul, KR;
Abstract
A method and system for diagnosing a failure of a rear oxygen sensor is provided. The sensor is determined to have failed if the difference between a maximum output value and a minimum value of the rear oxygen sensor is less than a first value, and if it is not, it is determined whether the difference is between the first value and a second value. If so, the air/fuel mixture is controlled to be richer than a stoichiometric air/fuel ratio for a predetermined period. Then, an output values of a front oxygen sensor and the rear oxygen sensor are respectively compared to first and second threshold values. If the output value of the front oxygen sensor is greater than the first threshold value, and the output value of the rear oxygen sensor is less than the second threshold value, it is determined that the rear oxygen sensor has failed.