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. 21, 2009
Filed:
Sep. 08, 2006
Paul D. Perry, Chatham, CA;
Paul D. Perry, Chatham, CA;
Continental Automotive Canada, Inc., Chatham, Ontario, CA;
Abstract
A technique is provided for detecting leaks in a fuel system such as an automotive fuel system. The technique complements an on-board diagnostics evaporative leak monitor that uses natural vacuum leak detection (NVLD). The technique utilizes the same switch and valve utilized by NVLD. Before engine shut-down, the system maintains a vacuum in the fuel tank and also provides a low-level purge flow. Upon engine shut-down, a timer is started and the NVLD switch is monitored to determine how long the vacuum is maintained in the tank. If the vacuum is maintained longer than a predetermined time period, then the system determines that the leak test is passed. If the vacuum decays faster than the predetermined time period, then the NVLD test is performed and system determines that the system passes the leak test if the NVLD test is passed.