Apparatus, system and method of establishing a test threshold for a fuel vapor leak detection system

• US 20040255657A1
• Filed: 12/17/2003
• Published: 12/23/2004
• Est. Priority Date: 12/17/2002
• Status: Active Grant

• Current Assignee: Continental Automotive GmbH (Continental AG)
• Original Assignee: Continental Automotive GmbH (Continental AG)
• Inventors: Veinotte, Andre, Perry, Paul D.
• Granted Patent: US 7,004,014 B2
• Time in Patent Office: Days
• US Class Current: 73/118.1
• CPC Class Codes: F02M 25/0809 Judging failure of purge control system
• CPC Class Codes: F02M 25/0836 Arrangement of valves controlling the admission of fuel vapour to an engine, e.g. valve being disposed between fuel tank or absorption canister and intake manifold

Abstract

An apparatus, system and method of establishing a threshold for a leak detection test that is performed on a headspace of a fuel system. A fuel vapor pressure management apparatus includes a housing, a pressure operable device, and a sensor. The housing defines an interior chamber. The pressure operable device separates the interior chamber into first and second portions, and includes a poppet that moves along an axis and a seal that is adapted to cooperatively engage the poppet. A first arrangement of the pressure operable device occurs during the leak detection test when the seal is in a first deformed configuration. A sensor detects the first arrangement of the pressure operable device during the leak detection test. And a processor is coupled to the sensor and reduces sensitivity of the fuel vapor pressure management apparatus during the leak detection test.

Claims

1. An apparatus establishing a threshold for a leak detection test performed on a headspace of a fuel system supplying fuel to an internal combustion engine of a vehicle, the apparatus comprising:

a fuel vapor pressure management apparatus including;

a housing defining an interior chamber;

a pressure operable device separating the interior chamber into first and second portions, the pressure operable device including a poppet movable along an axis and a seal adapted to cooperatively engage the poppet, a first arrangement of the pressure operable device occurs during the leak detection test when the seal is in a first deformed configuration; and

a sensor detecting the first arrangement of the pressure operable device during the leak detection test; and

a processor coupled to the sensor, the processor indicates the presence of a fault in the fuel system based on an evaluation of multiple failures by the sensor to detect the first arrangement.

2. The apparatus according to claim 1, wherein the processor determines that operation of the fuel vapor management apparatus in a pass/fail threshold range of leaks.

3. The apparatus according to claim 2, wherein the pass/fail threshold range of leaks is defined by intermittent passing and failing of the leak detection test.

4. The apparatus according to claim 1, further comprising:

a memory storing previous results of the leak detection test.

5. The apparatus according to claim 1, wherein the processor calculates an average of an accumulated number of times that the sensor detects the first arrangement of the pressure operable device.

6. The apparatus according to claim 1, wherein the first arrangement of the pressure operable device occurs during the leak detection test when there is a first negative pressure level in the first portion relative to the second portion, a second arrangement of the pressure operable device permits a first fluid flow from the second portion to the first portion when the seal is in a second deformed configuration, and a third arrangement of the pressure operable device permits a second fluid flow from the first portion to the second portion when the seal is in an undeformed configuration

7. A system for performing a leak detection test, the system comprising:

an internal combustion engine;

a fuel system supplying fuel to the internal combustion engine, the fuel system including a fuel tank and a headspace within the fuel tank;

a fuel vapor pressure management apparatus including;

a housing defining an interior chamber;

a pressure operable device separating the interior chamber into first and second portions, the pressure operable device including a poppet movable along an axis and a seal adapted to cooperatively engage the poppet, a first arrangement of the pressure operable device occurs during the leak detection test when the seal is in a first deformed configuration; and

a sensor detecting the first arrangement of the pressure operable device during the leak detection test; and

a processor coupled to the sensor, the processor indicating the presence of a fault in the fuel system based on an evaluation of multiple failures by the sensor to detect the first arrangement.

8. The system according to claim 7, further comprising:

a system malfunction indicator being actuated by the processor based on the evaluation of multiple failures by the sensor to detect the first arrangement.

9. The system according to claim 7, wherein the processor determines that operation of the fuel vapor management apparatus in a pass/fail threshold range of leaks.

10. The system according to claim 9, wherein the pass/fail threshold range of leaks is defined by intermittent passing and failing of the leak detection test.

11. The system according to claim 7, wherein the first arrangement of the pressure operable device occurs during the leak detection test when there is a first negative pressure level in the first portion relative to the second portion, a second arrangement of the pressure operable device permits a first fluid flow from the second portion to the first portion when the seal is in a second deformed configuration, and a third arrangement of the pressure operable device permits a second fluid flow from the first portion to the second portion when the seal is in an undeformed configuration

12. The system according to claim 7, wherein the processor comprises a control unit for the internal combustion engine.

13. A method comprising:

performing a leak detection test performed on a headspace of a fuel system supplying fuel to an internal combustion engine;

determining if the leak detection test is being performed at a pass/fail threshold range of leaks; and

decreasing a probability that the leak detection test will detect leaks in a lower portion of the pass/fail threshold range of leaks.

14. The method according to claim 13, wherein the pass/fail threshold range of leaks is defined by intermittent passing and failing of the leak detection test.

15. The method according to claim 13, further comprising:

coupling to the headspace a fuel vapor pressure management apparatus including;

a housing defining an interior chamber;

a pressure operable device separating the interior chamber into first and second portions, the pressure operable device including a poppet movable along an axis and a seal adapted to cooperatively engage the poppet, a first arrangement of the pressure operable device occurs during the leak detection test when there is a first negative pressure level in the first portion relative to the second portion and the seal is in a first deformed configuration, a second arrangement of the pressure operable device permits a first fluid flow from the second portion to the first portion when the seal is in a second deformed configuration, and a third arrangement of the pressure operable device permits a second fluid flow from the first portion to the second portion when the seal is in an undeformed configuration; and

a sensor detecting the first arrangement of the pressure operable device during the leak detection test.

16. The method according to claim 15, wherein the decreasing the probability of leak detection comprises evaluating a historical record of the sensor detecting the first arrangement.

17. The method according to claim 15, wherein the decreasing the probability of leak detection comprises calculating an average of an accumulated number of occurrences of the sensor detecting the first arrangement.

18. The method according to claim 14, further comprising:

indicating a system malfunction if the headspace has a leak at least as great as in an upper portion of the pass/fail threshold range of leaks.