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1. (WO2018045100) FUEL TANK SYSTEM AND METHOD FOR DETECTING AUTOMOTIVE FUEL SYSTEM LEAKS
Anmerkung: Text basiert auf automatischer optischer Zeichenerkennung (OCR). Verwenden Sie bitte aus rechtlichen Gründen die PDF-Version.

CLAIMS

What is claimed is:

1. A fuel tank system comprising:

a fuel tank;

a purge canister;

a valve assembly having an upstream canister valve that moves between an open position and a closed position to open and close an upstream vent line that fluidly connects the fuel tank and the purge canister; and

a controller that (i) conducts a first pressure test that measures a pressure in the fuel tank over a time, (ii) closes the upstream canister valve based on a determination that a leak exists, (iii) conducts a second pressure test that measures a pressure in the fuel tank over a time subsequent to closing the upstream canister valve and (iv) determines a location of the leak based on comparing the first pressure test and the second pressure test.

2. The fuel tank system of claim 1 , further comprising a filler pipe and cap assembly.

3. The fuel tank system of claim 2, wherein the valve assembly further comprises a recirculation line valve that moves between an open position and a closed position to open and close a recirculation line fluidly connected between the fuel tank and the filler pipe and cap assembly.

4. The fuel tank system of claim 3, wherein the controller (i) conducts a third pressure test that measures a pressure in the fuel tank over a time, and (ii) closes the recirculation line valve based on a determination that a leak exists, (iii) conducts a fourth pressure test that measures a pressure in the fuel tank over a time subsequent to closing the recirculation line valve and (iv) determines a location of the leak based on comparing the third pressure check and the fourth pressure check.

5. The fuel tank system of claim 1 , further comprising a pressure sensor that senses a pressure in the fuel tank.

6. The fuel tank system of claim 5, wherein the controller determines a measured pressure over time from the pressure sensor.

7. The fuel tank system of claim 6, wherein the controller compares the measured pressure over time and an expected pressure over time and determines whether a leak exists based on comparing the measured and expected pressures over time.

8. The fuel tank system of claim 1 wherein the fuel canister is adapted to collect fuel vapor emitted by the fuel tank and subsequently release the fuel vapor through a downstream canister vent line to an engine.

9. A fuel tank system comprising:

a fuel tank having a pressure sensor that measures a pressure in the fuel tank;

a filler pipe;

a purge canister;

a valve assembly including:

an upstream canister valve that moves between an open position and a closed position to open and close an upstream vent line that fluidly connects the fuel tank and the purge canister;

a recirculation line valve that moves between an open position and a closed position to open and close a recirculation line that fluidly connects the fuel tank and the filler pipe; and

an inlet check valve that moves between an open position and a closed position to open and close a vapor line that fluidly connects the fuel tank and the filler pipe; and

a controller that (i) conducts a first leak check wherein a first calculated pressure change is compared to a first measured pressure in the fuel tank, (ii) closes one of the upstream canister valve, recirculation line valve and inlet check valve, and (iii) conducts a second leak check wherein a second calculated pressure change is compared to a second measured pressure in the fuel tank, and (iii) determines a potential location of a leak based on the first and second leak checks.

10. The fuel tank system of claim 9 wherein the controller (iv) conducts a third leak check wherein a third calculated pressure change is compared to a third measured pressure in the fuel tank, and (v) determines a potential location of a leak based on the first and third leak check.

1 1. The fuel tank system of claim 10 wherein the third leak check includes closing the recirculation line valve.

12. The fuel tank system of claim 10 wherein the third leak check includes closing the inlet check valve.

13. The fuel tank system of claim 10 wherein the controller (vi) conducts a fourth leak check wherein a fourth calculated pressure change is compared to a fourth measured pressure in the fuel tank, and (v) determines a potential location of a leak based on the first and fourth leak check.

14. The fuel tank system of claim 13 wherein the fourth leak check includes closing the recirculation line valve.

15. The fuel tank system of claim 13 wherein the fourth leak check includes closing the inlet check valve.

16. The fuel tank system of claim 9 wherein the upstream canister valve,

recirculation line valve and inlet check valves are electrically actuated.

17. The fuel tank system of claim 9 wherein the fuel canister is adapted to

collect fuel vapor emitted by the fuel tank and subsequently release the fuel vapor

through a downstream canister vent line to an engine.

18. A method for detecting a leak in a fuel tank system, the method

comprising:

providing a fuel tank system having a fuel tank, a purge canister and a

valve assembly, the valve assembly having an upstream canister valve that moves

between an open position and a closed position to open and close an upstream vent

line that fluidly connects the fuel tank and the purge canister;

performing a first pressure test that measures a pressure in the fuel tank

over a time;

closing the upstream canister valve based on a determination that a leak

exists;

performing a second pressure test that measures a pressure in the fuel

tank over a time subsequent to closing the upstream canister valve; and

determining a location of the leak based on comparing the first pressure

test and the second pressure test.

19. The method of claim 18, wherein the fuel tank system further includes a filler pipe and cap assembly and a recirculation line valve that moves between an open position and a closed position to open and close a recirculation line fluidly connected between the fuel tank and the filler pipe and cap assembly, the method further comprising:

performing a third pressure test that measures a pressure in the fuel tank over a time; and

closing the recirculation line valve based on a determination that a leak exists.

20. The method of claim 19, further comprising:

performing a fourth pressure test that measures a pressure in the fuel tank over a time subsequent to closing the recirculation line valve; and

determining a location of the leak based on comparing the third pressure test and the fourth pressure test.