System and method for emptying a tank

• US 9,624,844 B2
• Filed: 07/22/2015
• Issued: 04/18/2017
• Est. Priority Date: 03/27/2012
• Status: Active Grant

• Current Assignee: Ford Global Technologies, LLC (Ford Motor Company)
• Original Assignee: Ford Global Technologies, LLC (Ford Motor Company)
• Inventors: Ulrey, Joseph Norman, Pursifull, Ross Dykstra, Lewis, Donald J.
• Primary Examiner(s): MOULIS, THOMAS N
• Application Number:
  US14/806,145
• Publication Number:
  US 20150322870A1
• Time in Patent Office: 636 Days
• Field of Search: 123525, 123527, 123575, 123198 D, 123198 DB
• CPC Class Codes: F02D 13/0234 changing the valve timing only
• CPC Class Codes: F02D 19/027 Determining the fuel pressure, temperature or volume flow, the fuel tank fill level or a valve position
• 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 19/0642 at least one fuel being gaseous, the other fuels being gaseous or liquid at standard conditions
• 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 19/08 simultaneously using pluralities of fuels F02D19/12 takes precedence
• CPC Class Codes: F02D 19/081 Adjusting the fuel composition or mixing ratio; Transitioning from one fuel to the other
• CPC Class Codes: F02D 2200/0406 Intake manifold pressure
• CPC Class Codes: F02D 2200/0602 Fuel pressure
• CPC Class Codes: F02D 41/0027 the fuel being gaseous non-electrical control F02D19/02
• CPC Class Codes: F02D 9/00 Controlling engines by throttling air or fuel-and-air induction conduits or exhaust conduits
• CPC Class Codes: Y02T 10/30 Use of alternative fuels, e.g. biofuels

Abstract

A system for method for emptying a gas storage tank of a vehicle is presented. In one example, engine valve timing is adjusted to facilitate reducing pressure within the gas storage tank. The system and method may extend the use of the gas stored in the gas storage tank.

Claims

1. A method for emptying a tank, comprising:

solely supplying a gaseous fuel to an engine when a pressure of the gaseous fuel is greater than a threshold pressure;

supplying the gaseous fuel and a liquid fuel when the pressure of the gaseous fuel is less than the threshold pressure; and

deactivating the supply of gaseous fuel to the engine when engine intake manifold pressure is greater than the pressure of the gaseous fuel.

2. The method of claim 1, further comprising deactivating the supply of gaseous fuel to the engine when engine intake manifold pressure is greater than ambient pressure.

3. The method of claim 2, further comprising deactivating the supply of gaseous fuel to the engine when a pressure of the gaseous fuel is substantially at ambient pressure.

4. The method of claim 3, where a fuel injector that is supplied with gaseous fuel injects the gaseous fuel into an intake manifold.

5. The method of claim 3, where the pressure of the gaseous fuel is within a storage tank.

6. The method of claim 3, where the pressure of the gaseous fuel is within a passage between a storage tank and the engine.

7. A method for emptying a tank, comprising:

supplying a gaseous fuel to an engine via a tank;

operating the engine with the gaseous fuel and a first valve timing at a first condition when a pressure of the gaseous fuel is greater than a first threshold;

operating the engine with the gaseous fuel and a second valve timing at the first condition when the pressure of the gaseous fuel is less than the first threshold; and

deactivating the gaseous fuel at each of intake manifold pressure greater than the pressure of the gaseous fuel and pressure of the gaseous fuel substantially at ambient pressure.

8. The method of claim 7, where the first condition is an engine speed and load.

9. The method of claim 7, where an intake valve of the engine opens later relative to a crankshaft position when the pressure of the gaseous fuel is less than the first threshold as compared to when the intake valve opens when the pressure of the gaseous fuel is greater than the first threshold.

10. The method of claim 7, further comprising injecting the gaseous fuel to a cylinder of the engine during an intake stroke of the cylinder when the pressure of the gaseous fuel is less than the first threshold.

11. The method of claim 10, further comprising injecting the gaseous fuel to the cylinder of the engine during a compression stroke of the cylinder when the pressure of the gaseous fuel is greater than the first threshold.

12. The method of claim 7, further comprising directly injecting the gaseous fuel into a cylinder of the engine via an injector.

13. A method for emptying a tank, comprising:

supplying a gaseous fuel to an engine via a tank;

operating the engine with a first gaseous fuel injector when a pressure of the gaseous fuel is greater than a first threshold;

operating the engine with a second gaseous fuel injector when the pressure of the gaseous fuel is less than the first threshold; and

deactivating each of the first and second injectors in response to the pressure of the gaseous fuel reaching different thresholds, respectively.

14. The method of claim 13, where the first gaseous fuel injector injects the gaseous fuel directly into a cylinder, and where the second gaseous fuel injector injects the gaseous fuel into an intake manifold.

15. The method of claim 14, where the first gaseous fuel injector is deactivated when the pressure of the gaseous fuel is less than the first threshold.

16. The method of claim 14, where the second gaseous fuel injector is deactivated when the pressure of the gaseous fuel is substantially ambient pressure.

17. The method of claim 16, further comprising activating a liquid fuel injector when the pressure of the gaseous fuel is less than a second threshold.

18. The method of claim 16, further comprising adjusting an engine air-fuel ratio in response to an output of an oxygen sensor via adjusting injection timing of a liquid fuel injector.

19. The method of claim 13, further comprising retarding opening timing of an intake valve of the engine in response to the pressure of the gaseous fuel while the first gaseous fuel injector is activated and while the second gaseous fuel injector is not activated.

20. The method of claim 13, further comprising deactivating the second gaseous fuel injector when a pressure of an intake manifold is greater than ambient pressure.