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. 20, 2004
Filed:
Jul. 31, 2001
Thomas L. Ting, Troy, MI (US);
John F. Van Gilder, Webberville, MI (US);
General Motors Corporation, Detroit, MI (US);
Abstract
A process for computer based, wholly passive, diagnosis of an automotive vehicle exhaust gas recirculation system is disclosed. Use is made of any suitable math model of the vehicle's air intake system to estimate the absolute pressure in the intake manifold, MAP, assuming both a healthy EGR system, MAP , and a faulty EGR valve, MAP . Both estimated values are compared with the actual normally measured manifold pressure, MAPmeas. Both comparisons are repeated over many calculations and the differences analyzed to reliably determine whether there is a real restriction to recirculated exhaust flow. A preferred math model of the intake system uses as input variables: mass air flow, barometric pressure, the position command for the EGR valve and engine speed.