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:
Jul. 21, 1998
Filed:
Jun. 17, 1997
Shinichi Abe, Aichi, JP;
Toyota Jidosha Kabushiki Kaisha, Aichi, JP;
Abstract
An apparatus, for controlling a heater for heating an air-fuel ratio sensor, which is capable of preventing an excessive temperature rise of the heater after the air-fuel ratio sensor has been activated. After engine start-up, power is continuously supplied to the heater 112 until its temperature reaches about 1100.degree. C. A basic power is determined so that the heater temperature is maintained at 1100.degree. C. after reaching 1100.degree. C., and so that the temperature of a sensing element 111 is maintained at 710.degree. C. after the air-fuel ratio sensor has been activated. The basic power is corrected in increasing direction using an auxiliary power calculated as a function of coolant temperature. After the air-fuel ratio sensor has been activated, if the increased power exceeds the 1100.degree. C. basic power, the power is limited below the 1100.degree. C. base power, to prevent the heater being damaged due to an excessive temperature rise of the heater.