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. 03, 2001
Filed:
Dec. 16, 1999
Craig Weldon, Chatham, CA;
Gilles Delaire, Chatham, CA;
Siemens Automotive Inc., Chatham, CA;
Abstract
A system and method for indicating leakage from a contained volume for holding volatile liquid, such as from an evaporative emission space of an automotive vehicle fuel system. A reciprocating pump operates to build pressure in the space toward a nominal test pressure. As the pressure is building toward nominal test pressure, but before nominal test pressure is achieved, measurements of substantially the amount of time required for the pump to execute a defined downstroke are repeatedly taken. These measurements may be referred to as pulse durations, and they are processed by an algorithm to detect when the rate of change in pulse duration changes from positive to negative, thereby defining the inflection point of a logistic curve. Subsequent measurements are taken and processed to predict a value at which substantially the pulse duration will ultimately stabilize. The predicted value is processed to indicate any leakage.