Fuel injector

Patent metadata

Field	Value
Publication number	US-11629679-B2
Application number	US-202117354699-A
Country	US
Kind code	B2
Filing date	Jun 22, 2021
Priority date	Jun 22, 2021
Publication date	Apr 18, 2023
Grant date	Apr 18, 2023

Abstract

A configuration is provided for a fuel injector for a common rail fuel system. In one example, the fuel injector may include a housing, an inner chamber enclosed by the housing, and a flow limiting valve. The flow limiting valve may be arranged at a downstream end of the inner chamber and also enclosed by the housing. This configuration may allow the fuel injector housing to have sufficient wall strength to withstand high pressure fuel injection and may allow effective fuel supply cut off when fuel cut off is demanded.

First claim

The invention claimed is:

1. A fuel injector, comprising:
a housing;
an inner chamber enclosed by the housing wherein the inner chamber has a first portion situated within a fuel injector head and a second portion situated within a fuel injector body; and
a flow limiting valve arranged at a downstream end of the inner chamber and also enclosed by the housing, wherein the flow limiting valve is positioned between the downstream end of the inner chamber and a solenoid valve.

2. The fuel injector of claim 1 , wherein an inlet of the fuel injector is located at a first, upstream end of the fuel injector and wherein fuel flows through the fuel injector from the first end, to a second end of the fuel injector, opposite of the first end.

3. The fuel injector of claim 1 , wherein the housing has a head at a top end of the housing, the head arranged upstream of a body of the housing, and wherein an outer diameter of the housing is reduced at the head relative to an outer diameter of the body.

4. The fuel injector of claim 3 , wherein a first thickness of the housing at the head is less than a second thickness of the housing at the body by an amount equal to or less than a threshold difference.

5. The fuel injector of claim 4 , wherein the threshold difference is between 5 to 25%.

6. The fuel injector of claim 3 , wherein a filter is enclosed by the head of the housing and the inner chamber, the flow limiting valve, and the solenoid valve are enclosed by the body of the housing.

7. The fuel injector of claim 1 , wherein the flow limiting valve is spaced away from a filter of the fuel injector by a length of the inner chamber, the length defined along a central axis of the fuel injector.

8. The fuel injector of claim 1 , wherein fuel is stored in the inner chamber, upstream of the flow limiting valve.

9. A common rail fuel system for an engine, comprising:
a high pressure fuel rail; and
a fuel injector configured to inject fuel from the high pressure fuel rail into a cylinder, the fuel injector including:
a filter positioned at an inlet of the fuel injector, the inlet located at a first end of the fuel injector, wherein the filter is upstream of an internal accumulator with a first portion of the internal accumulator situated within the fuel injector head and a second portion of the internal accumulator situated with the fuel injector body;
a flow limiting valve arranged in a mid-region along a length of the fuel injector, upstream of a solenoid valve, the flow limiting valve configured as a fuel cutoff during an overfueling event; and
an accumulator extending between the filter and the flow limiting valve.

10. The common rail fuel system of claim 9 , wherein the flow limiting valve is configured to close when the overfueling event is detected and wherein when closed, the flow limiting valve blocks flow of fuel from the accumulator to the cylinder.

11. The common rail fuel system of claim 9 , wherein fuel is not stored downstream of the flow limiting valve, between the flow limiting valve and the solenoid valve.

12. The common rail fuel system of claim 9 , wherein the flow limiting valve is spaced away from the filter by a length of the accumulator, the length parallel with a central axis of the fuel injector, and wherein the length of the accumulator is greater than either of a length of the filter and a length of the flow limiting valve.

13. The common rail fuel system of claim 9 , wherein the flow limiting valve is positioned closer to a second end of the fuel injector than the first end, the second end opposite of the first end and wherein the second end includes a nozzle.

14. The common rail fuel system of claim 13 , wherein the flow limiting valve is fluidly coupled to the nozzle by high pressure fuel passages and wherein fuel flow to the nozzle is adjusted based on a position of an orifice plate arranged in a path of the fuel flow between the solenoid valve and the nozzle.

15. The common rail fuel system of claim 14 , wherein the solenoid valve includes an electromagnetically actuated solenoid and a control valve plate coupled to the orifice plate and wherein the solenoid is configured to vary a position of a piston-like rod along a central axis of the fuel injector to create a pressure drop in a control volume above a nozzle needle and wherein creating the pressure drop causes the nozzle needle to lift from its seat and initiate fuel injection into the cylinder.

16. The common rail fuel system of claim 13 , wherein the flow limiting valve is configured to block fuel flow from the accumulator to the nozzle, independent of the position of the orifice plate, when the overfueling event is detected.

17. A fuel injector for a common rail fuel system, comprising:
a housing enclosing a plurality of inner components of the fuel injector, the plurality of inner components including a flow limiting valve arranged in between an accumulator and a solenoid valve of the fuel injector, wherein a thickness of a wall of the housing is thinner at a head of the fuel injector than at a body of the fuel injector by an amount equal to or less than a threshold difference, wherein the accumulator has a first portion situated within a fuel injector head and a second portion situated within a fuel injector body, and wherein the first portion has a length that is less than the length of the second portion.

18. The fuel injector of claim 17 , wherein the head of the fuel injector is circumferentially surrounded by a clamp, the clamp configured to maintain a position of the fuel injector in a cylinder head and wherein an outer diameter of the head of the fuel injector is reduced relative to an outer diameter of the body of the fuel injector.

19. The fuel injector of claim 17 , wherein the head of the fuel injector extends between an inlet of the fuel injector and the body of the fuel injector and wherein the thickness of the wall of the housing at the head is configured to withstand a high pressure of the common fail fuel system communicated to the fuel injector at the inlet of the fuel injector.

20. The fuel injector of claim 17 , wherein fuel is stored in the fuel injector entirely upstream of the flow limiting valve during operation of the fuel injector and during an overfueling event when the flow limiting valve is actuated to cut off fuel injection at a cylinder, and wherein during the overfueling event, an excess of fuel is injected relative to a target fueling quantity.

Assignees

• Transp Ip Holdings Llc

Inventors

• Leute Pisey
• Brumberg Justin Thomas
• Brigden Jesse

Classifications

• F02M63/0225

  Fuel-injection apparatus having a common rail feeding several injectors (F02M63/0003 takes precedence); Means for varying pressure in common rails; Pumps feeding common rails · CPC title

• F02M61/165 Primary

  Filtering elements specially adapted in fuel inlets to injector · CPC title

• F02M61/10 Primary

  Other injectors with elongated valve bodies, i.e. of needle-valve type · CPC title

• F02M47/027 Primary

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

• F02M2200/40

  Fuel-injection apparatus with fuel accumulators, e.g. a fuel injector having an integrated fuel accumulator · CPC title