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:
Sep. 30, 2014
Filed:
Mar. 17, 2011
Stephen Paul Levijoki, Swartz Creek, MI (US);
Rebecca J. Darr, Milford, MI (US);
Steve L. Melby, Howell, MI (US);
Stephen Paul Levijoki, Swartz Creek, MI (US);
Rebecca J. Darr, Milford, MI (US);
Steve L. Melby, Howell, MI (US);
GM Global Technology Operations LLC, Detroit, MI (US);
Abstract
A vehicle includes an engine, an exhaust system, a selective catalytic reduction (SCR) device, a first and a second NOx sensor configured to respectively measure an upstream and a downstream NOx level, and a controller or host machine. The controller, via the present method, calculates a NOx conversion efficiency rate of the SCR device using the NOx levels from the sensors. At the end of a key cycle when an accumulated amount of upstream NOx is less than a calibrated upstream NOx level, the controller determines if the NOx conversion efficiency rate is presently passing or failing. The accumulated upstream NOx is recorded in memory for use in calculating the NOx conversion efficiency rate during a subsequent key cycle only when the NOx conversion efficiency rate is presently passing at the end of the key cycle. A control system for the vehicle uses the controller and sensors as noted above.