APPROACH FOR CONTROLLING FUEL FLOW WITH ALTERNATIVE FUELS

• US 20110168132A1
• Filed: 05/28/2010
• Published: 07/14/2011
• 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
• Granted Patent: US 9,441,597 B2
• Time in Patent Office: Days
• US Class Current: 123/446
• CPC Class Codes: F02M 43/00 Fuel-injection apparatus operating simultaneously on two or more fuels, or on a liquid fuel and another liquid, e.g. the other liquid being an anti-knock additive
• CPC Class Codes: F02M 63/025 from the common rail
• CPC Class Codes: F02M 63/026 Means for reducing the pressure in common rails at power off pressure control F02D41/3845
• CPC Class Codes: F02M 63/027 More than one high pressure pump feeding a single common rail
• CPC Class Codes: Y10T 137/8597 Main line as motive fluid for follower-type feeder

Abstract

Fuel is evacuated from a fuel rail upon vehicle shut-off by directing fuel from a fuel pump to provide a motive flow for an ejector to pump fuel from the fuel rail to a fuel tank.

Claims

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

during a first mode of operation, directing fuel pumped by a fuel pump from a fuel tank to a fuel rail for injection to an engine; and

during a second mode of operation, directing fuel pumped by the fuel pump to an ejector to provide a motive flow for the ejector to pump fuel from the fuel rail to the fuel tank.

2. The method of claim 1, further comprising:

evacuating the fuel rail of fuel during the second mode, and shutting off the fuel pump in response to the fuel rail being substantially evacuated of fuel.

3. The method of claim 1, wherein a first valve is positioned downstream of the fuel pump and upstream of the fuel rail and a second valve is positioned upstream of ejector and downstream of the fuel tank, directing fuel pumped by the fuel pump from the fuel tank to the fuel rail includes opening the first valve and closing the second valve, and directing fuel pumped by the fuel pump to the ejector to provide a motive flow for the ejector to pump fuel from the fuel rail to the fuel tank includes closing the first valve and opening the second valve.

4. The method of claim 1, wherein the first mode is performed during a vehicle in-use condition and the second mode is performed during a vehicle shut-off condition.

5. The method of claim 1, wherein a type of fuel stored in the fuel tank includes liquid propane.

6. The method of claim 5, wherein the liquid propane is returned to the fuel tank in the second mode without use of a vacuum pump or a compressor other than the ejector.

7. 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 first valve positioned downstream of the fuel pump;

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

an ejector positioned in the fuel return line;

a second valve positioned downstream of the fuel tank and upstream of the ejector;

a motive flow line positioned downstream of the fuel pump and upstream of the first valve and connecting to the ejector; and

a controller for closing the first valve and opening the second valve to direct fuel pumped from the fuel pump to the ejector to provide a motive flow for the ejector to pump fuel from the fuel rail to the fuel tank to thereby evacuate fuel from the fuel rail.

8. The system of claim 7, wherein the controller evacuates the fuel rail by closing the first valve and opening the second valve in response a vehicle shut-off condition.

9. The system of claim 8, wherein the controller shuts off the fuel pump in response to evacuation of the fuel rail during the vehicle shut-off condition.

10. The system of claim 7, further comprising:

a first check valve positioned downstream of the fuel pump and upstream of the first valve; and

a second check valve positioned in the fuel return line downstream of the ejector.

11. The system of claim 7, further comprising:

a second ejector positioned in the fuel return line downstream of the ejector, an outlet of the second ejector communicating with an inlet of the ejector; and

the controller closing the first valve and opening the second valve to direct fuel pumped from the fuel pump to the second ejector to provide a motive flow for the ejector to pump fuel from the fuel rail to the ejector.

12. The system of claim 11, further comprising:

a first check valve set to a first actuating pressure positioned in the fuel return line between the outlet of the second ejector and the inlet of the ejector; and

a second check valve set to a second actuating pressure different from the first actuating pressure positioned in the fuel return line downstream of the second ejector.

13. The system of claim 7, wherein a type of fuel stored in the fuel tank includes liquid propane.

14. The system of claim 13, wherein the liquid propane is returned to the fuel tank during evacuation of the fuel rail without use of a vacuum pump or a compressor other than the ejector.

15. The system of claim 7 further comprising:

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

a second fuel tank positioned upstream of the fuel rail, the second fuel tank storing a second fuel type that is different from a fuel type that is stored in the fuel tank; and

the controller adjusting a state of the third valve to direct fuel from the fuel tank to the fuel rail in response to selecting fuel from the first fuel tank for combustion, and adjusting the state of the third valve to direct fuel from the second fuel tank to the fuel rail in response to selecting fuel from the second fuel tank for combustion.

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

a fuel rail;

a first fuel stage comprising;

a first fuel tank for storing a first fuel type;

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

a first valve positioned downstream of the first fuel pump;

a first fuel return line positioned upstream from the fuel rail and downstream from the first valve;

an ejector positioned in the first fuel return line;

a second valve positioned downstream of the first fuel tank and upstream of the ejector; and

a motive flow line positioned downstream of the first fuel pump and upstream of the first valve and connecting to the ejector;

a second fuel stage comprising;

a second fuel tank for storing a second fuel type different from the first fuel type; and

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

a third valve positioned upstream of the fuel rail between the first fuel stage and the second fuel stage.

17. The system of claim 16, further comprising:

a controller for, in a first mode, adjusting the third valve to direct fuel from the first fuel stage to the fuel rail based on selection of the first fuel type for combustion, and adjusting the third valve to direct fuel from the second fuel stage to the fuel rail based on selection of the second fuel type for combustion, and in a second mode, adjusting the third valve to direct fuel from the fuel rail to the first fuel stage, closing the first valve, and opening the second valve to direct fuel pumped by the first fuel pump to the ejector to provide a motive flow for the ejector to pump fuel from the fuel rail to the first fuel tank to thereby evacuate fuel from the fuel rail.

18. The system of claim 17 wherein the controller operates in the first mode during a vehicle in-use condition and operates in the second mode during a vehicle shut-off condition.

19. The system of claim 16, wherein the first fuel type includes liquid propane and the second fuel type includes gasoline.

20. The system of claim 16, wherein fuel is returned to the first fuel tank in the second mode without use of a vacuum pump or a compressor other than the ejector.