FUEL OXIDATION REDUCTION FOR HYBRID VEHICLES

• US 20150083089A1
• Filed: 09/24/2013
• Published: 03/26/2015
• Est. Priority Date: 09/24/2013
• Status: Active Grant

• Current Assignee: Ford Global Technologies, LLC (Ford Motor Company)
• Original Assignee: Ford Global Technologies, LLC (Ford Motor Company)
• Inventors: Pearce, Russell Randall, Kuenzel, Kenneth J.
• Granted Patent: US 9,488,136 B2
• Time in Patent Office: Days
• US Class Current: 123/520
• CPC Class Codes: F02M 25/0809 Judging failure of purge control system

Abstract

Systems and methods to control fuel tank pressure to reduce fuel oxidation in plug-in hybrid electric vehicles are disclosed. A method comprises routing vapors from a fuel system canister to the fuel tank to maintain the fuel tank pressure at a desired pressure. In this way, the engine may be maintained off for greater durations while still retaining fuel quality of fuel stored on-board the vehicle.

Claims

1. A method, comprising:

when fuel tank pressure is below a threshold, routing fuel vapors from a fuel system canister to the fuel tank to maintain the fuel tank pressure at a desired pressure.

2. The method of claim 1, wherein routing fuel vapors from the fuel system canister comprises activating a pump to evacuate the fuel system canister.

3. The method of claim 1, wherein routing fuel vapors from the fuel system canister to the fuel tank comprises opening a diverter valve to draw air into the fuel system canister pushing fuel vapors into the fuel tank.

4. The method of claim 3, further comprising sensing hydrocarbon concentration of the fuel vapors exiting the canister and entering the fuel tank, and closing the diverter valve when the hydrocarbon concentration is below a threshold concentration, but maintaining the diverter valve open when the hydrocarbon concentration is above the threshold concentration, the engine maintained at rest and non-combusting during both the open and closed diverter valve operation.

5. The method of claim 3, further comprising, closing the diverter valve when fuel tank pressure increases to above the threshold.

6. The method of claim 1, wherein the routing occurs without concurrently purging any fuel vapors to the engine.

7. A system, comprising:

a fuel tank;

a pressure sensor to sense vapor pressure within the fuel tank;

a vapor canister;

a vapor line between the fuel tank and the vapor canister; and

a pump located in the vapor line.

8. The system of claim 7, further comprising a fuel tank isolation valve in the vapor line.

9. The system of claim 7, further comprising a contractable foam insert within the fuel tank.

10. The system of claim 7, further comprising a contractable inner skin within the fuel tank.

11. The system of claim 7, further comprising a portion of the fuel tank wall comprised of a contractable material.

12. The system of claim 7, further comprising a contractable bladder within the fuel tank.

13. The system of claim 12, wherein the contractable bladder contains an inert gas.

15. The system of claim 7, wherein the vapor canister is part of a non-integrated refueling canister only system.

14. The system of 7, wherein the fuel tank can withstand a 45 kpa positive pressure and a 21 kpa negative pressure.

16. A system, comprising:

a fuel tank;

a pressure sensor to sense vapor pressure within the fuel tank;

a vapor canister;

a vapor line between the fuel tank and the vapor canister; and

a diverter valve.

17. The system of claim 16, wherein the diverter valve is located in a diverter line stemming from the vapor canister.

18. The system of claim 16, further comprising a hydrocarbon sensor in the vapor line.

19. The system of claim 17, wherein the hydrocarbon sensor senses hydrocarbon concentration in the vapor line and reports the hydrocarbon concentration to an engine controller.

20. The system of claim 16, wherein the diverter valve is closed when fuel tank pressure is above a threshold pressure.