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:
May. 21, 2002
Filed:
Sep. 13, 2000
Kenneth M. Simpson, Howell, MI (US);
Michael T. Cottrell, White Lake, MI (US);
Stephen F. Majkowski, Rochester Hills, MI (US);
Hallett D. Breidenbach, West Bloomfield, MI (US);
Alton L. Schuessler, Flint, MI (US);
Delphi Technologies, Inc., Troy, MI (US);
Abstract
An improved test method for an EGR system reliably detects debilitating EGR system restrictions without significantly degrading combustion stability and exhaust emissions. The EGR valve test opening for diagnostic purposes is initialized at a relatively low value, which is progressively increased if the resulting change in intake manifold pressure fails to exceed a threshold based on the minimum expected change in intake manifold pressure for an EGR system that is regarded as functioning within acceptable limits. As soon as the measured pressure change exceeds the threshold, the EGR system is deemed to pass the restriction test, and the test method is terminated. If the EGR valve opening reaches a maximum value without the measured pressure exceeding the threshold, the EGR system is deemed to fail the restriction test, and a fault indication is generated. Consequently, the test opening of the EGR valve is adaptively determined based on the measured intake manifold pressure change, and is never larger than required to reliably detect a debilitating EGR restriction. This allows reliable detection of a borderline failing EGR system, while preventing degradation of combustion stability and emissions in a substantially unrestricted EGR system.