System and method for operating a fuel injector

Patent metadata

Field	Value
Publication number	US-10907567-B2
Application number	US-201816022559-A
Country	US
Kind code	B2
Filing date	Jun 28, 2018
Priority date	Jan 3, 2018
Publication date	Feb 2, 2021
Grant date	Feb 2, 2021

Abstract

Methods and systems for operating a direct fuel injector of an internal combustion engine are described. In one example, a nozzle needle is moved in two directions to maintain fuel flow through the direct fuel injector and to reduce the possibility of the nozzle needle impacting a piezoelectric actuator. The method and system may permit long fuel injection times without causing undesirable impacts between components of a fuel injector.

First claim

The invention claimed is:

1. A fuel injector operating method, comprising:
moving a nozzle needle into contact with a nozzle needle seat by commanding a fuel injector open a plurality of times during a cycle of a cylinder,
wherein the fuel injector is commanded open each of the plurality of times by applying a first current to a piezoelectric actuator of the fuel injector via an electronic engine controller, and
wherein a timing for commanding the fuel injector open the plurality of times is based on a predetermined fuel injection pulse width that has been partitioned into sections.

2. The fuel injector method of claim 1 , further comprising moving the nozzle needle into contact with the nozzle needle seat by commanding the fuel injector closed a plurality of times via the controller before the nozzle needle is moved into contract with the nozzle needle seat.

3. The fuel injector method of claim 2 , where the nozzle needle is commanded closed each of the plurality of times before the nozzle needle is moved into contact with the nozzle needle seat by applying a second current to the actuator in a second direction via the controller.

4. The fuel injector method of claim 2 , where the controller commands the fuel injector closed via applying a second current to the actuator of the fuel injector, wherein the first current is applied in a first direction, and wherein the second current is applied in a second direction.

5. The fuel injector method of claim 1 , where the nozzle needle is in an open state when the nozzle needle is not contacting the nozzle needle seat.

6. The fuel injector method of claim 1 , where contacting the nozzle needle with the nozzle needle seat substantially stops fuel flow through the fuel injector, and further comprising:
adjusting timing of commanding the fuel injector in response to output of a position sensor.

7. The fuel injector method of claim 1 , where commanding the fuel injector open the plurality of times causes diesel fuel to flow directly into an engine cylinder, and where an injected fuel quantity is proportional to or a function of a sum of the closing command times minus a sum of the opening command times for a plurality of fuel injector commands.

8. A fuel injector operating method, comprising:
lifting a nozzle needle from a nozzle needle seat via a piezoelectric actuator and changing a direction of motion of the nozzle needle a plurality of times before contacting the nozzle needle with the nozzle needle seat during a cycle of a cylinder, wherein the plurality of times is three or fewer times, and wherein the piezoelectric actuator is supplied current by the electronic engine controller.

9. The fuel injector method of claim 8 , further comprising maintaining a position of the nozzle needle above a position where flow through the fuel injector is throttled to less than a rated flow rate of the fuel injector between an initial opening command of the fuel injector and a final closing command of the fuel injector, the initial opening command and the final closing command defining a duration of a fuel injection pulse during the cylinder cycle.

10. The fuel injector method of claim 8 , where the changing direction of motion of the nozzle needle includes flowing current to the fuel injector in a first direction and in a second direction.

11. The fuel injector method of claim 10 , further comprising changing the direction of motion of the nozzle needle without impacting the nozzle needle to a piezoelectric actuator or a device that is between the nozzle needle and the piezoelectric actuator.

12. The fuel injector method of claim 8 , where the nozzle needle is lifted via output of a controller.

13. A fuel injection system, comprising:
a direct fuel injector including a nozzle needle and a nozzle needle seat; and
an electronic engine controller including executable instructions stored in non-transitory memory that cause the nozzle needle to transition from moving in an opening direction to moving in a closing direction without fully closing the direct fuel injector before moving the nozzle needle in the opening direction again, the direct fuel injector transitioned from moving in the opening direction to moving in the closing direction based on a needle position rate of change to prevent the nozzle needle from impacting a piezoelectric actuator or a device that is between the nozzle needle and the piezoelectric actuator.

14. The fuel injection system of claim 13 , where the direct fuel injector is fully closed when the nozzle needle is in contact with the nozzle needle seat, and further comprising:
additional instructions to change a direction of motion of the nozzle needle a plurality of times after opening the direct fuel injector and before fully closing the direct fuel injector.

15. The fuel injection system of claim 14 , where the direction of motion of the nozzle needle is changed via changing a direction of current flow to the direct fuel injector.

16. The fuel injection system of claim 14 , further comprising additional instructions to lift the nozzle needle in response to a position of an engine.

17. The fuel injection system of claim 13 , further comprising additional instructions to seat the nozzle needle in response to a desired amount of fuel being injected to an engine.

Assignees

• Ford Global Tech Llc

Inventors

• Pohlkamp Kyle
• Kurtz Eric

Classifications

• F02D41/403

  with pilot injections · CPC title

• F02D41/2096

  for controlling piezoelectric injectors (drive and control circuit for piezoelectric devices in general H10N30/802) · CPC title

• F02D41/405

  with post injections · CPC title

• F02D2041/389

  for injecting directly into the cylinder · CPC title

• F02D41/402 Primary

  Multiple injections · CPC title