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:
Jan. 19, 1993
Filed:
Nov. 22, 1991
Yukio Miyashita, Wako, JP;
Hiroshi Ohno, Wako, JP;
Kunio Noguchi, Wako, JP;
Hironao Fukuchi, Wako, JP;
Abstract
A method of detecting deterioration of an exhaust gas ingredient concentration sensor for use in controlling an air-fuel ratio of a mixture supplied to an internal combustion engine having an exhaust system in which the sensor is arranged. The sensor has an output characteristic approximately proportional to concentration of a specific ingredient in exhaust gases emitted from the engine. The air-fuel ratio is feedback-controlled to a desired air-fuel ratio by calculating an amount of fuel supplied to the engine by the use of a desired air-fuel ratio coefficient indicative of the desired air-fuel ratio and set in dependence on operating conditions of the engine, and an air-fuel ratio correction coefficient set in dependence on a value of an output from the sensor and the desired air-fuel ratio coefficient. A plurality of average values of the air-fuel ratio correction coefficient are calculated, respectively, when the desired air-fuel ratio falls within a plurality of predetermined ranges. The average values thus calculated are compared with each other. A degree of deterioration of the sensor is determined from results of the comparison. Further, a method of feedback-controlling the air-fuel ratio in the above-mentioned manner, in which the value of the output from the sensor is corrected in response to the degree of deterioration thus determined.