SYSTEM AND METHOD FOR IMPROVING FUEL VAPOR PURGING FOR AN ENGINE HAVING A COMPRESSOR

• US 20100012099A1
• Filed: 07/18/2008
• Published: 01/21/2010
• Est. Priority Date: 07/18/2008
• Status: Active Grant

• Current Assignee: Ford Global Technologies, LLC (Ford Motor Company)
• Original Assignee: Ford Global Technologies, LLC (Ford Motor Company)
• Inventors: Surnilla, Gopichandra, Cunningham, Ralph Wayne, Kerns, James Michael, Pursifull, Ross Dykstra, Leone, Thomas G.
• Granted Patent: US 7,743,752 B2
• Time in Patent Office: Days
• US Class Current: 123/520
• CPC Class Codes: F02D 41/0007 for control of turbo-charged or super-charged engines control of the pumps per se F02B37/12
• CPC Class Codes: F02D 41/0042 Controlling the combustible mixture as a function of the canister purging, e.g. control of injected fuel to compensate for deviation of air fuel ratio when purging
• 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
• CPC Class Codes: F02M 25/089 Layout of the fuel vapour installation
• CPC Class Codes: F02M 33/04 returning to the intake passage

Abstract

A system and method for storing and purging fuel vapors for an internal combustion engine comprising a compressor is presented. The system allows the canister to be purged even while the engine is operated at high engine load.

Claims

1. A system for purging a vehicle'"'"'s fuel vapor storage canister, the system comprising:

an internal combustion engine;

a throttle for regulating air flow to the internal combustion engine;

a compressor located upstream from the throttle in the engine'"'"'s intake system; and

a fuel vapor canister that is in communication with an engine'"'"'s intake system at a first location that is downstream from the compressor, and the fuel vapor canister also in communication with the engine'"'"'s intake system at a second location that is downstream from the throttle.

2. The system of claim 1 wherein a first valve is placed in ducting that leads from the compressor outlet to the fuel vapor canister and wherein a second valve is placed in ducting that leads from the canister to a location in the engine'"'"'s intake system downstream from the throttle body.

3. The system of claim 2 further comprising a controller to operate the first and second valves such that the canister is purged by flowing air from the outlet of the compressor to the second location downstream from the throttle.

4. The system of claim 1 wherein a duct puts a fuel tank in communication with the fuel vapor canister and wherein a valve blocks flow from the vapor canister to a fuel tank.

5. The system of claim 1 further comprising a controller that adjusts a valve to control the pressure in the fuel canister.

6. The system of claim 1 further comprising a controller that adjusts the compressor and the position of a throttle to adjust the pressure in the fuel vapor canister.

7. The system of claim 1 wherein a pressure relief valve vents the fuel vapor canister if pressure in the fuel vapor canister exceeds a threshold.

8. The system of claim 1 wherein a duct puts a fuel tank in communication with the engine'"'"'s intake system at a location upstream of the compressor.

12. The method of claim 1 I wherein the outlet pressure of a turbocharger is controlled by adjusting the position of a waste gate or variable geometry turbine vanes.

9. A method for purging fuel vapors from a canister to an internal combustion engine having a compressor, the method comprising:

directing a portion of a compressor'"'"'s output to a fuel vapor canister, the compressor in communication with an internal combustion engine'"'"'s intake manifold; and

controlling pressure in the internal combustion engine'"'"'s intake manifold by adjusting the position of a throttle and the flow rate from the fuel vapor canister to the intake manifold.

10. The method of claim 9 wherein a variably controlled valve is used to control the rate of flow from the fuel vapor canister to the intake manifold.

11. The method of claim 9 wherein the rate of flow from the fuel vapor canister to the intake system is controlled by adjusting the outlet pressure of a compressor.

13. The method of claim 9 further comprising venting the fuel tank to a location in the intake system that is upstream from the inlet of the compressor when a pressure in the fuel tank is greater than a threshold.

14. A method for storing and purging fuel vapors in a canister of an internal combustion engine having a compressor, the method comprising:

drawing fuel vapors from a fuel tank to a canister using intake manifold vacuum during a first condition; and

applying a positive air pressure to the canister to push fuel vapors from the canister into an intake manifold during a second condition.

15. The method of claim 14 wherein the first condition is when pressure in the fuel tank is greater than a threshold.

16. The method of claim 14 wherein the second condition is when pressure in the intake manifold is above atmospheric pressure.

17. The method of claim 14 further comprising drawing vapors from the fuel tank to the intake system and bypassing a canister when pressure in the fuel tank is greater than a threshold.

18. The method of claim 17 wherein the vapors are drawn into the intake system upstream from a compressor.

19. The method of claim 14 wherein the fuel vapors are pushed from the canister to a location in the intake system upstream from the compressor.

20. The method of claim 14 wherein the amount of fuel injected to the engine during the second condition is reduced in proportion to the amount of actual or estimated fuel vapor pushed from the canister to the intake system.

21. The method of claim 20 wherein the amount of fuel injected to the engine is adjusted using an oxygen sensor.

22. The method of claim 14 wherein the first condition is when the engine'"'"'s intake manifold pressure is less than barometric pressure.