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. 11, 1993
Filed:
Jun. 04, 1992
Walter Viess, Schwieberdingen, DE;
Hans Koehnle, Salzgitter, DE;
Robert Bosch GmbH, Stuttgart, DE;
Abstract
An exhaust-gas recirculation system includes means for diagnosing the system based upon temperature values measured in the exhaust-gas return duct when certain conditions exist. A differential value between the actual temperature in the exhaust-gas return duct and a reference temperature, which indicates the possible beginning of diagnosis, is provided for a flow-through test. The differential value is then fed to a low-pass filter. If the conditions for a diagnosis are satisfied, it is determined whether the recirculation system is in order based upon a comparison of the differential value to a threshold value. A leak test of the exhaust-gas return valve can likewise be performed based upon the differential value of the two temperatures.