Fuel injector having dry-running protection valve and fuel system using same

Patent metadata

Field	Value
Publication number	US-11280306-B1
Application number	US-202117150159-A
Country	US
Kind code	B1
Filing date	Jan 15, 2021
Priority date	Jan 15, 2021
Publication date	Mar 22, 2022
Grant date	Mar 22, 2022

Abstract

A fuel injector includes an injector housing, a check control valve assembly within the injector housing, a direct-operated check, a valve biaser supported on the injector housing, and a dry-running protection valve trapped between the valve biaser and the injector housing. The dry-running protection valve limits expelling drained actuation fluid from the fuel injector to enable filling a low-pressure volume therein in advance of filling a low pressure drain line common to a plurality of fuel injectors in an internal combustion engine system.

First claim

What is claimed is:

1. A fuel injector comprising:
an injector housing defining a longitudinal axis and having formed therein an actuation fluid inlet and an actuation fluid outlet, and including a nozzle having formed therein a nozzle supply passage and a plurality of spray outlets;
a check control valve assembly within the injector housing;
a direct-operated check movable between a closed position blocking the plurality of spray outlets from the nozzle supply passage, and an open position;
a valve biaser supported outside of the injector housing on an outer surface of the injector housing having the actuation fluid outlet formed therein;
a dry-running protection valve trapped between the valve biaser and the injector housing and movable, in opposition to a biasing force of the valve biaser, from a closed position blocking the actuation fluid outlet to an open position; and
a check control chamber is formed in the injector housing, and the check control valve assembly includes a check control valve fluidly between the check control chamber and the actuation fluid outlet.

2. The fuel injector of claim 1 wherein:
the actuation fluid inlet is a pressurized fuel inlet fluidly connected to the nozzle supply passage;
a check control chamber is formed in the fuel injector, and the direct-operated check includes a closing hydraulic surface exposed to the check control chamber; and
the check control valve assembly includes a control valve movable between a closed position, blocking the check control chamber from the actuation fluid outlet, and an open position.

3. The fuel injector of claim 1 wherein the valve biaser includes a spring band at least partially circumferential of the injector housing.

4. The fuel injector of claim 3 wherein the spring band is fully circumferential of the injector housing and has a relief split formed therein.

5. The fuel injector of claim 3 wherein the injector housing includes a wet seat forming the actuation fluid outlet and contacted by the dry-running protection valve at the closed position.

6. The fuel injector of claim 5 wherein the valve biaser includes a dry seat, and the dry-running protection valve is in contact with the dry seat at each of the closed position and the open position.

7. The fuel injector of claim 3 wherein the dry-running protection valve includes a ball valve.

8. The fuel injector of claim 1 wherein the injector housing forms an outside groove extending circumferentially around the longitudinal axis, and the valve biaser is within the outside groove.

9. The fuel injector of claim 8 wherein:
the injector housing includes an outside housing surface defining an injector boundary; and
the outside groove is formed radially inward of the outside housing surface and the valve biaser is within the injector boundary at each of the closed position and the open position of the dry-running protection valve.

10. An engine head assembly comprising:
an engine head having an injector bore formed therein;
a fuel injector within the injector bore and including an injector housing defining a longitudinal axis and having formed therein an actuation fluid inlet and an actuation fluid outlet, and including a nozzle having formed therein a nozzle supply passage and a plurality of spray outlets;
a check control valve assembly within the injector housing;
a direct-operated check movable between a closed position blocking the plurality of spray outlets from the nozzle supply passage, and an open position;
a valve biaser within the injector bore, the valve biaser being located outside of the injector housing between the injector housing and the engine head and supported on an outer surface of the injector housing exposed to the injector bore and having the actuation fluid outlet formed therein; and
a dry-running protection valve trapped between the valve biaser and the injector housing and movable, in opposition to a biasing force of the valve biaser, from a closed position blocking the actuation fluid outlet to an open position.

11. The engine head assembly of claim 10 wherein:
the injector housing forms an outside groove extending circumferentially around the longitudinal axis, and the valve biaser is within the outside groove; and
the injector housing includes an outside housing surface defining an injector boundary, and the outside groove is formed radially inward of the outside housing surface and the valve biaser is within the injector boundary at each of the closed position and the open position of the dry-running protection valve.

12. The engine head assembly of claim 10 wherein the valve biaser includes a spring band.

13. The engine head assembly of claim 12 wherein the dry-running protection valve includes a ball valve.

14. The engine head assembly of claim 13 wherein the spring band has a relief split formed therein.

15. The engine head assembly of claim 12 wherein the spring band is circumferential of the injector housing and supported on the injector housing.

16. The engine head assembly of claim 10 further comprising:
a first fuel seal between the injector housing and the engine head within the injector bore and positioned upon a first axial side of the actuation fluid outlet; and
a second fuel seal between the injector housing and the engine head within the injector bore and positioned upon a second axial side of the actuation fluid outlet.

17. The engine head assembly of claim 10 wherein the engine head has a second injector bore formed therein, and further comprising a second fuel injector having a second dry-running protection valve and a second valve biaser, and a fuel return conduit, and wherein each of the first dry-running protection valve and the second dry-running protection valve is fluidly between the fuel return conduit and the respective first fuel injector or second fuel injector.

18. A method of operating a fuel system for an engine comprising:
operating check control valve assemblies in each of a plurality of fuel injectors in the fuel system to open and close outlet checks in the plurality of fuel injectors;
draining actuation fluid from check control chambers in the plurality of fuel injectors based on the operation of the check control valve assemblies;
limiting expelling the drained actuation fluid through an actuation fluid outlet in each respective one of the plurality of fuel injectors with dry-running protection valves of each of the plurality of fuel injectors;
filling low-pressure volumes in each of the plurality of fuel injectors with the drained actuation fluid in advance of filling a low pressure return conduit common to the plurality of fuel injectors, based on the limiting of the expelling of the drained actuation fluid;
expelling actuation fluid through the actuation fluid outlets, based on operation of the check control valve assemblies, after the filling of the low-pressure volumes in each of the plurality of fuel injectors; and
the expelling actuation fluid in each respective fuel injector further including expelling the actuation fluid in opposition to a bias of a valve biaser within an injector bore between an outer surface of an injector housing and an engine head.

19. The method of claim 18 wherein the actuation fluid is pressurized fuel.

20. The method of claim 19 wherein the limiting of the expelling of the drained actuation fluid includes limiting expelling the drained actuation fluid with dry-running protection valves each including a ball valve biased toward a closed position blocking an

Assignees

• Caterpillar Inc

Inventors

• Bannur Nagaraja Manjunath
• Tatikonda Venkata R
• Tower Benjamin R

Classifications

• F02M69/383

  the fuel passing through different passages to injectors or to a drain, the pressure of fuel acting on valves to close or open selectively these passages · CPC title

• F02M63/0054 Primary

  Check valves (F02M59/462, F02M59/464 take precedence) · CPC title

• F02M47/027

  Electrically actuated valves draining the chamber to release the closing pressure · CPC title

• F02M47/022

  Mechanically actuated valves draining the chamber to release the closing pressure · CPC title

• F02M61/14

  Arrangements of injectors with respect to engines; Mounting of injectors · CPC title