SYSTEM AND METHOD FOR IMPROVING OPERATION OF A FUEL INJECTOR AT LOWER TEMPERATURES

• US 20080127951A1
• Filed: 12/05/2006
• Published: 06/05/2008
• Est. Priority Date: 12/05/2006
• Status: Active Grant

• Current Assignee: Ford Global Technologies, LLC (Ford Motor Company)
• Original Assignee: Ford Global Technologies, LLC (Ford Motor Company)
• Inventors: Maranville, Clay, Elie, Larry, Gale, Allan
• Granted Patent: US 7,690,354 B2
• Time in Patent Office: Days
• US Class Current: 123/549
• CPC Class Codes: F02D 2041/2065 the control being related to the coil temperature
• CPC Class Codes: F02D 41/20 Output circuits, e.g. for controlling currents in command coils
• CPC Class Codes: F02M 53/04 Injectors with heating, cooling, or thermally-insulating means

Abstract

A system and method to heat a fuel injector is described. Resistive heating may be selectively applied to improve the performance of a fuel injector. Specifically, current can be supplied to an electrically operable mechanical valve to improve the operation of the valve at lower temperatures. The method can improve engine performance and lower emissions, at least under some conditions.

Claims

1. A method for reducing the variation in the amount of fuel delivered by a fuel injector to a cylinder of an internal combustion engine, the method comprising:

adjusting current flow to a coil of a fuel injector, said current flow being varied between first and second frequencies, said first and second frequencies being non-zero, said current not acting to change the operating state of said fuel injector.

2. The method of claim 1 wherein said first and second frequencies are related to an operating condition.

3. The method of claim 1 wherein said current is used to heat said coil.

4. The method of claim 1 further comprising adjusting the duration that said first or second frequency is delivered to said coil as engine temperature changes.

5. The method of claim 1 wherein said coil is a closing coil.

6. The method of claim 1 wherein said current flows to said first coil of said fuel injector during a predetermined interval.

7. The method of claim 1 wherein the amplitude of current delivered to said coil at said first frequency is different than the amplitude of current delivered to said coil at said second frequency.

8. A method for reducing the variation in the amount of fuel delivered by a fuel injector to a cylinder of an internal combustion engine, the method comprising:

starting and stopping a current flowing to a coil of a fuel injector that provides fuel to a cylinder of an internal combustion engine a plurality of times, during at least a portion of a time when said internal combustion engine is being prepared for a start, said current supplied while maintaining the operating state that said fuel injector assumed prior to starting and stopping said current flow; and

varying the duration of said starting and stopping of said current flow as a state of a charging system varies.

9. The method of claim 8 further comprising regulating said current to control the temperature of said coil.

10. The method of claim 8 wherein said coil is a closing coil.

11. The method of claim 8 wherein said operating state is an “

open”

or “

closed”

state.

12. The method of claim 8 wherein said engine is prepared to start by activating at least a glow plug that heats at least a cylinder of said internal combustion engine.

13. The method of claim 8 wherein said method is used to supply current in a sequential manner to a plurality of fuel injectors.

14. The method of claim 13 wherein said method continues to heat said plurality of fuel injectors after said engine has started.

15. The method of claim 8 wherein said engine is prepared to start in response to an operator request or in response to a request of another system of a vehicle.

16. The method of claim 8 wherein said fuel injector injects diesel fuel.

17. The method of claim 8 wherein an amount of said current is varied as engine operating conditions vary or as operating conditions of said injector vary.

18. A method for reducing the variation in the amount of fuel delivered by a fuel injector to a cylinder of an internal combustion engine, the method comprising:

starting and stopping current flow at a first non-zero frequency to a closing coil of a fuel injector that provides fuel to a cylinder of an internal combustion engine when an engine is being prepared for a start, said current supplied while maintaining the operating state of said fuel injector; and

starting and stopping current flow at a second non-zero frequency to said closing coil of said injector after said internal combustion engine is started, said current supplied while maintaining the operating state of said fuel injector, said starting and stopping of current done during an interval of a cylinder cycle wherein fuel flow is stopped to said cylinder.

19. The method of claim 18 wherein said operating state is a closed state.

20. The method of claim 18 further comprising regulating said current to control the temperature of said coil.

21. A system for reducing the variation in the amount of fuel delivered by a fuel injector to a cylinder of an internal combustion engine, the method comprising:

a fuel injector having an opening coil and a closing coil, said fuel injector capable of injecting fuel directly into a cylinder of an internal combustion engine; and

a controller for starting and stopping current flow a plurality of times to said closing coil of said injector while maintaining a rate that fuel is being injected to a cylinder, during a cycle of said cylinder.

22. The system of claim 21 further comprising a glow plug that increases the temperature of said cylinder during at least a portion of the time that current flow is started and stopped to said closing coil.

23. The system of claim 21 wherein said rate is zero.

24. The system of claim 21 wherein said rate is non-zero.

25. The system of claim 21 further comprising varying said rate as a demanded engine torque varies.

26. A system for reducing the variation in the amount of fuel delivered by a fuel injector to a cylinder of an internal combustion engine, the method comprising:

a fuel injector having an opening coil and a closing coil, said fuel injector capable of injecting fuel directly into a cylinder of an internal combustion engine; and

a controller for starting and stopping current flow a plurality of times at a first non-zero frequency and at a second non-zero frequency to said closing coil of said fuel injector while maintaining the operating state of said injector.