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. 07, 2002
Filed:
Nov. 10, 1999
Stephen F. Majkowski, Rochester Hills, MI (US);
Kenneth M. Simpson, Howell, MI (US);
Delphi Technologies, Inc., Troy, MI (US);
Abstract
An improved method of detecting evaporative emission system leaks, wherein first and second changes in closed-system fuel tank pressure due to vapor generation are measured respectively prior to and after the leak testing, and wherein the larger of the first and second pressure changes is used to adjust the pressure measurements taken during leak testing, or to invalidate the diagnostic if the vapor generation exceeds a threshold. The first vapor generation test occurs at the beginning of the driving cycle when there has been no significant disturbance of the vapor equilibrium in the fuel tank, and thereby provides an indication vapor generation due to volatility of the fuel. The second vapor generation test occurs well into the driving cycle, and provides an indication of vapor generation due to fuel heating and sloshing.