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. 25, 1994
Filed:
Nov. 17, 1992
Akihiro Nakashima, Chiryu, JP;
Toshiaki Mizuno, Kariya, JP;
Nippondenso Co., Ltd., Kariya, JP;
Abstract
A catalyst deterioration detection apparatus having oxygen sensors disposed in the upper stream and the lower stream from a ternary catalyst disposed in the exhaust system of an internal combustion engine, controlling so as to make the air/fuel ratio of the internal combustion engine to be in the neighborhood of a theoretical air/fuel ratio in response to an output signal from at least either of the oxygen sensors, detecting a response delay time from a moment an output signal from the upper stream oxygen sensor has been changed to a moment an output signal from the lower stream oxygen sensor has been changed when the air/fuel ratio of the internal combustion engine is changed from the rich side to the lean side or from the lean side to the rich side, and discrimination that the catalyst has deteriorated if the response delay time is shorter than a predetermined value, the catalyst deterioration detection apparatus including a device for permitting the catalyst deterioration detection apparatus to perform the detection operation if a fact that the internal combustion engine is in a predetermined operation state has been detected and a fact that the air/fuel ration has been converged to the neighborhood of the theoretical air/fuel ratio has been detected.