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. 14, 2012
Filed:
Jul. 15, 2010
Akira Umehara, Kariya, JP;
Akira Umehara, Kariya, JP;
Denso Corporation, Kariya, JP;
Abstract
An actual intake air quantity at the time when the intake air quantity is changed compulsorily with an EGR valve is measured with an airflow meter. An oxygen concentration of exhaust gas after combustion in a diesel engine is estimated based on the measured actual intake air quantity and a fuel injection quantity of the diesel engine. The estimated oxygen concentration is compared with an actual oxygen concentration sensed with an A/F sensor, thereby sensing response of the A/F sensor. Even if a response time for causing a change in the intake air quantity with the EGR valve changes, the change of the response time does not affect the estimate of the oxygen concentration since the oxygen concentration is estimated based on the actual intake air quantity. Therefore, the response of the A/F sensor can be sensed with high accuracy.