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:
Aug. 20, 1996
Filed:
Jun. 07, 1995
Jun Hasegawa, Kariya, JP;
Shigenori Isomura, Kariya, JP;
Tomomichi Mizoguchi, Nagoya, JP;
Yasutaka Nakamori, Anjo, JP;
Nippondenso Co., Ltd., Kariya, JP;
Abstract
To shorten the time during which oxygen concentration cannot be detected, the temperature of an oxygen concentration sensor is detected by negatively biasing the sensor using a bias control circuit. A microcomputer estimates a saturated current thereof at one time before the current flowing through the sensor section ends rising based on a current detected by a current detecting circuit at that time. Further, the sensor is positively biased right after the elapse of a negative bias voltage application period by the bias control circuit. The microcomputer determines the air-fuel ratio based on the current flowing through the sensor at that time. The period in which the negative bias is applied is variably set appropriately by the microcomputer in response to changes of engine temperature and intake air amount. Furthermore, to activate the sensor quickly, the temperature of the sensor section is detected and a heater is controlled based thereon.