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:
Apr. 04, 1989
Filed:
Mar. 19, 1987
Masahiko Asakura, Wako, JP;
Tomohiko Kawanabe, Wako, JP;
Minoru Muroya, Wako, JP;
Shin'ichi Kubota, Wako, JP;
Katsuhiko Kimura, Wako, JP;
Yasunari Seki, Wako, JP;
Kouji Matsuura, Wako, JP;
Honda Giken Kogyo Kabushiki Kaisha, Tokyo, JP;
Abstract
An apparatus for sensing the concentration of oxygen in a gas such as engine exhaust gas includes an oxygen concentration sensor formed of an oxygen pump element and a sensor cell element, each based on a solid electrolytic member formed of a material such as ZrO.sub.2, and is provided with a limiter circuit which functions to reduce the level of current supplied to the oxygen pump element when a voltage produced by the sensor cell element indicates that this current level is such as to produce a 'blackening' phenomenon whereby deterioration of the oxygen pump element will occur and oxygen concentration sensing reliability will be lowered. The apparatus also includes a delay circuit which functions such that a reduction of the oxygen pump element current level is delayed by a predetermined time interval, after an increase of the sensor cell element voltage to the 'blanking' region is detected, thereby preventing fluctuations in the oxygen pump element current level due to transient increases in sensor cell element voltage and increasing the sensing reliability.