Fuel weathering method for vehicle evaporative emission system

• US 6,435,164 B1
• Filed: 12/07/2000
• Issued: 08/20/2002
• Est. Priority Date: 12/07/2000
• Status: Expired due to Term

• Current Assignee: Ford Global Technologies, LLC (Ford Motor Company)
• Original Assignee: Ford Global Technologies, LLC (Ford Motor Company)
• Inventors: Lehmen, Allen Joseph, Kaiser, Jeffrey, Gernant, Timothy
• Primary Examiner(s): Moulis, Thomas N.
• Application Number:
  US09/732,285
• Publication Number:
  US 20020104516A1
• Time in Patent Office: 621 Days
• Field of Search: 123/1.A, 123/516, 123/518, 123/519, 731/19.A, 731/181
• US Class Current: 123/516
• CPC Class Codes: F02M 25/0809 Judging failure of purge control system
• CPC Class Codes: H04L 12/66 Arrangements for connecting between networks having differing types of switching systems, e.g. gateways
• CPC Class Codes: H04L 67/565 Conversion or adaptation of application format or content adding application control or application functional data H04L67/561
• CPC Class Codes: H04L 67/63 Routing a service request depending on the request content or context
• CPC Class Codes: H04L 69/08 Protocols for interworking; Protocol conversion

Abstract

A fuel weathering method for an evaporative emission system of a motor vehicle includes determining a current temperature of liquid fuel inside the evaporative emission system, determining a fuel residency time representing the amount of time the fuel has resided above the current temperature, and performing a system diagnostic test of the evaporative emission system only if the fuel residency time exceeds a minimum fuel residency time.

Claims

1. A fuel weathering method for an evaporative emission system of a motor vehicle, comprising:

determining a current temperature of liquid fuel inside the evaporative emission system;

determining a fuel residency time representing the amount of time the fuel has resided above the current temperature; and

performing a diagnostic test of the evaporative emission system only if the fuel residency time exceeds a minimum fuel residency time.

2. A fuel weathering method for an evaporative emission system of a motor vehicle, comprising:

determining a current temperature of liquid fuel inside the evaporative emission system;

incrementing at least one fuel residency counter corresponding to a predetermined temperature range of the fuel to maintain a cumulative record of the amount of time the fuel has resided within the predetermined temperature range;

performing a diagnostic test of the evaporative emission system only if the fuel residency counter exceeds a minimum value corresponding to the temperature range.

3. The method according to claim 2, further comprising:

determining, prior to said step of determining the current fuel temperature, whether the vehicle has been recently refueled; and

reinitializing the at least one fuel residency counter if said vehicle has been recently refueled.

4. A fuel weathering system for an evaporative emission system of a motor vehicle, comprising:

a sensor for measuring a current temperature of liquid fuel inside the evaporative emission system; and

a controller coupled to the sensor for determining a fuel residency time representing the amount of time the fuel has resided above the current temperature, and for performing a diagnostic test of the evaporative emission system only if the fuel residency time exceeds a minimum fuel residency time.

5. The system according to claim 4, wherein said controller comprises counter means for incrementing at least one fuel residency counter corresponding to a predetermined temperature range wherein the at least one fuel residency counter is used to maintain a cumulative record of the amount of time the fuel has resided within the predetermined temperature range.

6. An article of manufacture for taking into account fuel weathering in the monitoring of emissions from an evaporative emission system of a motor vehicle, comprising:

a computer usable medium; and

a computer readable program code embodied in the computer usable medium for directing a computer to control the steps of determining a current temperature of liquid fuel inside the evaporative emission system, determining a fuel residency time representing the amount of time the fuel has resided above the current temperature; and

performing a diagnostic test of the evaporative emission system only if the fuel residency time exceeds a minimum fuel residency time.