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. 18, 1992
Filed:
Jul. 01, 1991
Richard S Davis, Romeo, MI (US);
General Motors Corporation, Detroit, MI (US);
Abstract
A system is disclosed for diagnosing faulty check valve operation in an internal combusiton engine having a back flow preventing check valve positioned in each intake air passage leading to an engine cylinder. The system measures the pressure in the engine air induction system, upstream of each check valve and downstream from an air intake throttle valve. The system produces an indication of faulty check valve operation, when an abnormal fluctuation in the measured pressure is detected. Preferably, the diagnostic function is performed when the engine operates in a defined mode, at idle speeds with light engine loading, where the pressure differential appearing across each check valve is essentially maximized. The engine cylinder associated with a faulty check valve is identified based upon the sensed rotational position of the engine when an abnormal fluctuation in pressure is detected.