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:
Oct. 05, 2010
Filed:
Mar. 02, 2007
Hirofumi Shouda, Toyota, JP;
Eijirou Yamada, Hekinan, JP;
Hirofumi Shouda, Toyota, JP;
Eijirou Yamada, Hekinan, JP;
Denso Corporation, Kariya, JP;
Abstract
An exhaust gas sensor for detecting oxygen concentration in exhaust gas is disposed in an exhaust pipe of an internal combustion engine. The sensor including a heater is controlled by a system that includes an electronic control unit. Water vapor contained in the exhaust gas is condensed on the sensor when the exhaust gas temperature is low. If the water condensation occurs while the sensor is heated by the heater, a sensor element may be cracked due to local cooling by the condensed water. To avoid the water condensation, the exhaust gas temperature is raised by retarding ignition timing of the engine for a certain period after the engine is started. After the exhaust gas is heated to a certain level, the sensor is heated. Alternatively, heating of the sensor is prohibited until the exhaust gas temperature becomes to a level at which no water condensation occurs. Thus, the cracking of the sensor element is avoided while making a delay of sensor activation minimal.