Approach for controlling fuel flow with alternative fuels

• US 8,196,567 B2
• Filed: 05/28/2010
• Issued: 06/12/2012
• Est. Priority Date: 05/28/2010
• Status: Active Grant

• Current Assignee: Ford Global Technologies, LLC (Ford Motor Company)
• Original Assignee: Ford Global Technologies, LLC (Ford Motor Company)
• Inventors: Pursifull, Ross Dykstra, Ulrey, Joseph Norman
• Primary Examiner(s): Cronin, Stephen K
• Assistant Examiner(s): NAJMUDDIN, RAZA NEHAL
• Application Number:
  US12/790,676
• Publication Number:
  US 20110168133A1
• Time in Patent Office: 746 Days
• Field of Search: 123575-578, 123/467, 123/525, 123/527, 123/516, 123/518, 123/519, 123/520, 123/514, 123/198.D, 123/198.DB, 701/112
• US Class Current: 123/495
• CPC Class Codes: F02D 19/0605 to adjust the fuel pressure or temperature
• CPC Class Codes: F02D 19/0615 being initiated by automatic means, e.g. based on engine or vehicle operating conditions
• CPC Class Codes: F02D 19/0628 Determining the fuel pressure, temperature or flow, the fuel tank fill level or a valve position
• CPC Class Codes: F02D 19/0647 the gaseous fuel being liquefied petroleum gas [LPG], liquefied natural gas [LNG], compressed natural gas [CNG] or dimethyl ether [DME]
• CPC Class Codes: F02D 19/0676 Multi-way valves; Switch-over valves
• CPC Class Codes: F02D 19/0684 High pressure fuel injection systems; Details on pumps, rails or the arrangement of valves in the fuel supply and return systems
• CPC Class Codes: F02D 19/0694 operating with a plurality of fuels
• CPC Class Codes: F02M 25/089 Layout of the fuel vapour installation
• CPC Class Codes: F02M 37/0064 for engines being fed with multiple fuels or fuels having special properties, e.g. bio-fuels; varying the fuel composition controlling engines working with pluralities of fuels F02D19/06
• CPC Class Codes: Y02T 10/30 Use of alternative fuels, e.g. biofuels

Abstract

Fuel is evacuated from a fuel rail by directing liquid fuel from the fuel rail to a fuel tank and then by directing gaseous fuel from the fuel rail to a fuel vapor canister.

Claims

1. A method for controlling fuel flow in a vehicle comprising:

during a vehicle shut-off condition;

during a first mode of operation, directing liquid fuel from a fuel rail to a fuel tank until fuel rail pressure becomes less than a threshold; and

then

during a second mode of operation, directing gaseous fuel from the fuel rail to a fuel vapor canister, the fuel vapor canister positioned external to the fuel tank.

2. The method of claim 1, further comprising:

after transitioning out of the first mode in response to the fuel rail pressure becoming less than the threshold, operating in the second mode.

3. The method of claim 1, wherein the threshold is a pressure level at which fuel in the fuel rail changes phase from liquid fuel to gaseous fuel.

4. The method of claim 1, further comprising:

after transitioning out of the second mode, directing a different fuel type to the fuel rail.

5. The method of claim 1, wherein directing fuel from the fuel rail to the fuel tank includes opening a first valve located in a return line positioned between the fuel rail and the fuel tank.

6. The method of claim 5, wherein directing fuel from the fuel rail to the fuel vapor canister includes closing the first valve and opening a second valve located in an evaporation line positioned between the fuel rail and the fuel vapor canister.

7. The method of claim 1, wherein a fuel type in the fuel rail includes liquid propane and the fuel rail is evacuated without use of a vacuum pump or a compressor.

8. A system for controlling fuel flow in a vehicle, comprising:

a fuel tank;

a fuel rail positioned downstream of the fuel tank;

a fuel return line positioned downstream of the fuel tank and upstream of the fuel rail;

a first valve located in the return line between the fuel rail and the fuel tank;

a fuel vapor canister positioned external to the fuel tank;

an evaporation line positioned between the fuel rail and the fuel vapor canister;

a second valve positioned in the evaporation line between the fuel rail and the fuel vapor canister; and

a controller for, during a first mode, opening the first valve and closing the second valve to direct liquid fuel from the fuel rail to the fuel tank until fuel rail pressure becomes less than a threshold, and then during a second mode, closing the first valve and opening the second valve to direct gaseous fuel from the fuel rail to the fuel vapor canister,

wherein the controller operates in the first and second modes during a vehicle shut-off condition.

9. The system of claim 8, wherein the return line couples to the fuel rail at a first position and the evaporation line couples to the fuel rail at a second position that is located higher than the first position.

10. The system of claim 8, wherein after transitioning out of the first mode, the controller operates in the second mode.

11. The system of claim 10, wherein the threshold is a pressure level at which fuel in the fuel rail changes phase from liquid fuel to gaseous fuel.

12. The system of claim 11, wherein a type of fuel in the fuel rail includes liquid propane and the threshold is a pressure level at which liquid propane transitions to gaseous fuel.

13. The system of claim 8, further comprising:

a second fuel tank for storing a second fuel type;

a second fuel pump to pump fuel from the second fuel tank;

a fourth valve positioned between the second fuel pump and the fuel rail; and

the controller, after operating in the second mode, opening the fourth valve and operating the second fuel pump to direct the second fuel type to the fuel rail.

14. A system for controlling fuel flow in a vehicle, comprising:

a fuel tank;

a fuel pump operable to pump fuel from the fuel tank;

a fuel rail positioned downstream of the fuel pump;

a fuel return line positioned between the fuel tank and the fuel rail;

a first valve located in the return line between the fuel rail and the fuel tank;

a fuel vapor canister positioned external to the fuel tank;

an evaporation line positioned between the fuel rail and the fuel vapor canister;

a second valve positioned in the evaporation line between the fuel rail and the fuel vapor canister;

a third valve positioned between the fuel pump and the fuel rail; and

a controller for, in a fuel rail evacuation mode during a vehicle shut-off condition, opening the first valve, closing the second valve, and closing the third valve to direct liquid fuel from the fuel rail to the fuel tank when a fuel rail pressure is greater than a threshold pressure level at which fuel in the fuel rail transitions from liquid fuel to gaseous fuel, and closing the first valve, opening the second valve, and closing the third valve to direct gaseous fuel from the fuel rail to the fuel vapor canister after the fuel rail pressure has dropped below the threshold pressure level to thereby evacuate fuel from the fuel rail.

15. The system of claim 14, wherein a fuel type in the fuel rail includes liquid propane and the fuel rail is evacuated without use of a vacuum pump or a compressor.

16. The system of claim 14, wherein the return line couples to the fuel rail at a first position and the evaporation line couples to the fuel rail at a second position that is located higher than the first position.

17. The system of claim 14, further comprising:

a second fuel tank for storing a second fuel type;

a second fuel pump to pump fuel from the second fuel tank;

a fourth valve positioned between the second fuel pump and the fuel rail; and

the controller, after operating in the second mode, opening the fourth valve and operating the second fuel pump to direct the second fuel type to the fuel rail.