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:
Jun. 28, 1988
Filed:
Feb. 21, 1986
Tetsusyo Yamada, Aichi, JP;
NGK Spark Plug Co., Ltd., Nagoya, JP;
Abstract
An air/fuel ratio sensor apparatus which is capable of detecting deterioration of the sensing elements and correcting the output of the apparatus accordingly. The apparatus includes two sensing elements and a closed compartment of which the two sensing elements define at least portions. One of the sensing elements is used as an oxygen concentration measuring cell, and the other as an oxygen pump cell. When the internal combustion engine with which the sensor is associated is running without fuel supply, a reference voltage used for controlling the oxygen pumping current is set to a smaller value than that employed when the engine is running with a fuel supply. Deterioration of the sensing elements is then detected by comparing the output air/fuel ratio signal produced at that time with a preset fixed value.