Internal-combustion engines – Charge forming device – Having fuel vapor recovery and storage system
Reexamination Certificate
2003-01-15
2004-12-14
Gimie, Mahmoud (Department: 3747)
Internal-combustion engines
Charge forming device
Having fuel vapor recovery and storage system
Reexamination Certificate
active
06830039
ABSTRACT:
FIELD OF THE INVENTION
The present invention generally relates to systems and methods of purge valve flow control for use with evaporative emissions control systems, and particularly relates to systems and methods for determining purge valve flow tolerance.
BACKGROUND OF THE INVENTION
Variable flow rate purge valves used in evaporative emissions control systems suffer from problems relating to part-to-part tolerance. For example, flow rate at low duty cycle can vary from part-to-part by as much as three-hundred percent, resulting in serious drivability issues at low engine speeds, especially with smaller displacement engines. As a result, past evaporative emissions control systems have not been able to utilize less expensive purge valves with less demanding part-to-part tolerance. As a further result, other solutions have focused on utilizing constant flow rate purge valves to avoid the tolerance issue.
What is needed is a solution that allows evaporative emissions control systems to utilize less expensive purge valves with less demanding part-to-part tolerance. Thus, the need remains for an adaptive system and method of purge valve control that is capable of determining purge valve tolerance and operating accordingly. The present invention fulfills this need.
SUMMARY OF THE INVENTION
In one aspect of the invention, a method for determining purge valve flow tolerance for use with evaporative emissions control systems includes developing an equation based on data relating purge valve duty cycle to flow, wherein the equation describes a flow curve with reference to a first axis and a second axis. The method further includes using the equation as a base equation for flow, and adapting the equation for part-to-part tolerance as a function of an intercept point of the equation with respect to the first axis, wherein the first axis relates to duty cycle.
In another aspect of the invention, a purge valve flow tolerance determination system for use with evaporative emissions control systems includes a memory storing an equation based on data relating purge valve duty cycle to flow, wherein the equation describes a flow curve with reference to a first axis and a second axis. A purge valve operation module is adapted to operate a purge valve based on the equation. An adaptation module adapts the equation for part-to-part tolerance as a function of an intercept point of the equation with respect to the first axis, wherein the first axis relates to duty cycle.
Further areas of applicability of the present invention will become apparent from the detailed description provided hereinafter. It should be understood that the detailed description and specific examples, while indicating the preferred embodiment of the invention, are intended for purposes of illustration only and are not intended to limit the scope of the invention.
REFERENCES:
patent: 5209202 (1993-05-01), Maurer et al.
patent: 5269274 (1993-12-01), Flaetgen et al.
patent: 5469823 (1995-11-01), Ott et al.
patent: 5529047 (1996-06-01), Aota et al.
patent: 6102364 (2000-08-01), Busato
patent: 6253750 (2001-07-01), Duty et al.
patent: 6722347 (2004-04-01), Sanchez et al.
Duty Mark J
Weber Gregory T
Bacon, Jr. Edwin W.
DaimlerChrysler Corporation
Gimie Mahmoud
LandOfFree
System and method for determining purge valve flow tolerance does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with System and method for determining purge valve flow tolerance, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and System and method for determining purge valve flow tolerance will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-3329548