Method for operating a direct fuel injector

Patent metadata

Field	Value
Publication number	US-8997714-B2
Application number	US-201313852824-A
Country	US
Kind code	B2
Filing date	Mar 28, 2013
Priority date	Mar 28, 2013
Publication date	Apr 7, 2015
Grant date	Apr 7, 2015

Abstract

A method, comprising: operating an engine cylinder with fuel from a first injector and not a second injector and activating the second injector in response to a rail pressure increase of a fuel rail, the fuel rail coupled to the second injector. In this way, degradation of the second injector may be reduced by activating the second injector and allowing fuel flow through the second injector to reduce the pressure and temperature of the fuel rail.

First claim

The invention claimed is:

1. A method, comprising:
operating an engine cylinder with fuel from a first injector and not a second injector; and
activating the second injector in response to a rail pressure increase of a fuel rail, the fuel rail coupled to the second injector.

2. The method of claim 1 wherein the second injector is activated in response to rail pressure increasing above a threshold, the rail pressure increase corresponding to a temperature increase, the threshold corresponding to a maximum temperature threshold.

3. The method of claim 2 , further comprising deactivating the second injector when the rail pressure decreases below the threshold.

4. The method of claim 1 wherein fuel is trapped in the fuel rail while monitoring the pressure increase, the method further comprising activating a fuel pump coupled to the fuel rail in response to the rail pressure increase.

5. The method of claim 4 further comprising adjusting injection of the first injector responsive to activation of the second injector.

6. The method of claim 1 wherein the second injector activation is further based on a fuel rail rigidity.

7. The method of claim 1 , wherein the injector activation is further based on a fuel coefficient of thermal expansion.

8. The method of claim 1 , further comprising adjusting a parameter of a cooling system coupled to the fuel rail in response to the rail pressure increase of the fuel rail.

9. The method of claim 8 , where the parameter is a flow rate of a coolant.

10. The method of claim 8 , where the parameter is a temperature of a coolant.

11. A fuel system for an internal combustion engine, comprising:
a group of direct fuel injectors in communication with a group of cylinders;
a first fuel rail in communication with the group of direct injectors;
a higher-pressure fuel pump in communication with the first fuel rail; and
a control system configured with instructions for: during a first condition, increasing a flow of fuel through the first fuel rail when a temperature change in a fuel included in the first fuel rail exceeds a threshold, the temperature change based on a rail pressure change.

12. The system of claim 11 , where the first condition includes a bulk fuel flow through the group of direct fuel injectors being substantially equal to zero.

13. The system of claim 12 , further comprising: a group of port fuel injectors in communication with the group of cylinders.

14. The system of claim 13 , further comprising: a second fuel rail in communication with the group of port fuel injectors; and
a lower-pressure fuel pump in communication with the second fuel rail.

15. The system of claim 14 , where the group of port fuel injectors is in use during the rail pressure change.

16. The system of claim 11 , where increasing the flow of fuel through the first fuel rail includes activating the higher-pressure fuel pump.

17. The system of claim 11 , where allowing fuel flow through a direct fuel injector system includes activating the group of direct fuel injectors.

18. The system of claim 11 , where the temperature change is determined as a function of the change in pressure over conditions with the group of injectors deactivated, the increasing of fuel flow including reactivating at least one injector from the group.

19. A method, comprising:
operating an engine cylinder with fuel from a first injector and not a second injector; and
activating a fuel pump coupled to the second injector in response to a rail pressure increase of a fuel rail, the fuel rail coupled between the second injector and the pump.

20. The method of claim 19 wherein the second injector is activated in response to rail pressure increasing above a threshold, the rail pressure increase corresponding to a temperature increase, the threshold corresponding to a maximum temperature threshold.

Assignees

• Ford Global Tech Llc

Inventors

• Rumpsa Todd Anthony

Classifications

• F02M53/043

  with cooling means other than air cooling · CPC title

• F02M63/0265 Primary

  Pumps feeding common rails · CPC title

• F02D2200/0606

  Fuel temperature · CPC title

• F02D2200/0602

  Fuel pressure · CPC title

• F02D41/3863 Primary

  by controlling the flow out of the common rail, e.g. using pressure relief valves · CPC title