WO2016099507A1

WO2016099507A1 - Fuel injector nozzle

Info

Publication number: WO2016099507A1
Application number: PCT/US2014/071138
Authority: WO
Inventors: Frank HUSMEIER
Original assignee: Cummins Inc.
Priority date: 2014-12-18
Filing date: 2014-12-18
Publication date: 2016-06-23

Abstract

A fuel injector nozzle is provided comprising a needle valve bore having a distal end, an upper sac section extending from the distal end of the needle valve bore, an intermediate sac section extending from the upper sac section, a bottom sac section extending from the intermediate sac section, the upper sac section, intermediate sac section and bottom sac section defining a sac volume, and a plurality of metering holes extending from the sac volume to outlet openings of the nozzle. At least one of the metering holes including an inlet opening formed partially in the upper sac section and partially in the intermediate sac section.

Description

FUEL INJECTOR NOZZLE

TECHNICAL FIELD

[0001] The present invention relates to fuel injectors and more particularly to fuel injector nozzles that provide high fuel flow with low sac volume and low cavitation.

BACKGROUND

[0002] For fuel injectors, sac volume is a critical parameter to control to reduce, among other things, soot generation which is regulated by government authorities. For larger engines, emissions due to sac volume is especially important during engine idle. The smaller the sac volume, generally speaking, the lower the soot. For large engines such as locomotive engines which may idle 80% or more of the time, sac volume is particularly important because only so much DPF may be used to permit efficient operation. As is generally known in the art, to control emission efficiency especially in such large engines, it is desirable to provide a large cup flow while reducing the sac volume. In prior art systems, large cup flow is accomplished by providing large spray holes in the nozzle of the fuel injector, which generally required a larger sac volume. Moreover, placement of the fuel delivery holes in the fuel injector can, in some instances, increase cavitation of the fuel, which over time degrades the performance of the fuel injector.

SUMMARY

[0003] According to the principles of the present disclosure, a fuel injector configuration is provided that enables large fuel delivery holes with low sac volumes. The configurations of the present disclosure also include placement of the fuel delivery holes at a location relative to the overall sac volume that permits improved fuel flow into the holes with reduced cavitation. Finally, the configuration of the present disclosure includes a large radius or an entirely flat bottom wall of the sac volume that creates high pressure which pushes fuel into the fuel delivery holes.

[0004] According to one embodiment of the present disclosure, a fuel injector nozzle is provided comprising: a needle valve bore having a distal end, an upper sac section extending from the distal end of the needle valve bore; an intermediate sac section extending from the upper sac section; a bottom sac section extending from the intermediate sac section, the upper sac section, intermediate sac section and bottom sac section defining a sac volume; and a plurality of metering holes extending from the sac volume to outlet openings of the nozzle, the plurality of metering holes each including an inlet opening formed partially in the upper sac section and partially in the intermediate sac section.

[0005] In one aspect of this embodiment, the upper sac section is formed by a cylindrical wall that defines a cylindrical upper volume of the sac volume. In another aspect, the upper sac section is formed by a conical wall that defines a conical upper volume of the sac volume. In yet another aspect, the intermediate sac section is formed by a conical wall that defines a conical intermediate volume of the sac volume. In still another aspect of this embodiment, the upper sac section has a maximum diameter and the bottom sac section is formed by a bottom wall that has a radius which is greater than one -half the maximum diameter. Another aspect further comprises a transition radius between the upper sac section and the intermediate sac section. Yet another aspect further comprises a transition radius between the intermediate sac section and the bottom sac section. In still another aspect, the plurality of metering holes each include a longitudinal axis that extends into the sac volume at a location below a transition between the upper sac section and the intermediate sac section. In a variant of this aspect, the conical wall of the upper sac section forms an angle with a longitudinal axis of the needle valve bore of up to 15 degrees. In another variant, the conical wall of the intermediate sac section forms an angle with a wall forming the upper sac section of between 90 and 180 degrees. In yet another aspect, the bottom wall radius is at least 100 percent greater than one-half the maximum diameter of the upper sac section.

[0006] In another embodiment, the present invention provides a fuel injector, comprising: a needle valve having a tip and configured for reciprocal movement along a longitudinal axis between an opened and a closed position, and a valve body including a needle valve bore configured to receive the needle valve and having a seat that engages the needle valve tip when the needle valve is in the closed position and a distal end, an upper sac section extending from the distal end of the needle valve bore, an intermediate sac section extending from the upper sac section, a bottom sac section extending from the intermediate sac section, the upper sac section, intermediate sac section and bottom sac section defining a sac volume, and a plurality of metering holes extending from the sac volume to outlet openings of the valve body, at least one of the plurality of metering holes including an inlet opening formed partially in the upper sac section and partially in the intermediate sac section. In one aspect of this embodiment, the upper sac section is formed by a cylindrical wall that defines a cylindrical upper volume of the sac volume. In another aspect, the upper sac section is formed by a conical wall that defines a conical upper volume of the sac volume. In yet another aspect, the intermediate sac section is formed by a conical wall that defines a conical intermediate volume of the sac volume. In another aspect of this embodiment, the upper sac section has a maximum diameter and the bottom sac section is formed by a bottom wall that has a radius which is greater than one-half the maximum diameter. Another aspect further comprises a transition radius between the upper sac section and the intermediate sac section. Yet another aspect further comprises a transition radius between the intermediate sac section and the bottom sac section. In still another aspect, the plurality of metering holes each include a longitudinal axis that extends into the sac volume at a location below a transition between the upper sac section and the intermediate sac section. In another aspect at least one of the plurality of metering holes includes an inlet opening formed partially in the intermediate sac section and partially in the bottom sac section.

[0007] According to another embodiment, the present disclosure provides a method, comprising: providing fuel through a needle valve having a tip and configured for reciprocal movement along a longitudinal axis between an opened and a closed position, routing the fuel into an upper sac section of a needle valve bore when the needle valve is in an opened position, routing the fuel into an intermediate sac section extending from the upper sac section, routing the fuel into a bottom sac section extending from the intermediate sac section, the upper sac section, intermediate sac section and bottom sac section defining a sac volume, and routing the fuel through a plurality of metering holes extending from the sac volume to outlet openings of the valve body, the plurality of metering holes each including an inlet opening formed partially in the upper sac section and partially in the intermediate sac section. In one aspect of this embodiment, the upper sac section is formed by a conical wall that defines a conical upper volume of the sac volume. In another aspect, the intermediate sac section is formed by a conical wall that defines a conical intermediate volume of the sac volume. In yet another aspect, the upper sac section has a maximum diameter and the bottom sac section is formed by a bottom wall that has a radius which is greater than one -half the maximum diameter. BRIEF DESCRIPTION OF THE DRAWINGS

[0008] Embodiments of the present invention will now be described, by way of example only, with reference to the accompanying drawings, in which:

[0009] Figure 1 is a schematic side view of a nozzle according to one embodiment of the disclosure overlaid onto a prior art nozzle;

[0010] Figure 2 is a sectional side view of a nozzle according to one embodiment of the disclosure overlaid onto a prior art nozzle;

[0011] Figure 3 is a sectional side view of one embodiment of a nozzle according to the present disclosure;

[0012] Figure 4 is an enlarged sectional side view of a portion of the nozzle of Figure 3;

[0013] Figure 5 is side view, partly in section, of the nozzle of Figure 3 with a needle valve in a closed position;

[0014] Figure 6 is a sectional side view of another embodiment of a nozzle according to the present disclosure;

[0015] Figure 7 is an enlarged sectional side view of a portion of the nozzle of Figure 6; and

[0016] Figure 8 is a side view, partly in section, of the nozzle of Figure 6 with a needle valve in a closed position.

DETAILED DESCRIPTION OF EMBODIMENTS OF THE DISCLOSURE

[0017] The embodiments described below are merely exemplary and are not intended to limit the invention to the precise forms disclosed. Instead, the embodiments were selected for description to enable one of ordinary skill in the art to practice the invention.

[0018] Referring now to Figure 1, a schematic representation of portions of a prior art fuel injector nozzle 10 is shown in dashed lines. The portion depicted is the internal volume of the distal end or tip portion of the nozzle. More specifically, nozzle 10 includes a valve seat 12, a cylindrical sac section formed by a cylindrical wall 14 and a bottom sac section formed by a bottom wall 16. As shown, nozzle 10 is centered on a longitudinal axis 18 and cylindrical wall 14 has a diameter 20. [0019] Nozzle 22 of the present disclosure which is superimposed on nozzle 10 in solid lines includes a valve seat 24, an upper sac section formed by a conical wall 26 which extends from valve seat 24, an intermediate sac section formed by a conical wall 28 which extends from conical wall 26 of upper sac section, and a bottom sac section formed by a bottom wall 30 which extends from conical wall 28. As shown, conical wall 26 and conical wall 28 intersect at a transition 32 and conical wall 28 and bottom wall 30 intersect at a transition 34. As is further described below, transitions 32, 34 may be either angular transitions or radius transitions or a combination of both. It should be noted that conical wall 26 may be replaced by a cylindrical wall (as described below). As such, wall 26 may form an angle with axis 18 of the needle valve bore of up to 15 degrees. Additionally, conical wall 28 may form an angle with wall 26 of between 90 and 180 degrees. Conical wall 26 has a maximum diameter 36 and bottom wall 30 has a radius 38 which is greater than one-half of maximum diameter 36. In certain embodiments, radius 38 may be between at least 100 percent greater than one -half the maximum diameter 36.

[0020] Referring now to Figure 2, a larger portion of nozzle 10 is shown with portions of nozzle 22 superimposed thereon. A plurality of metering holes 40 extend from bottom wall 16 through the body 42 of nozzle 10. Nozzle 22 also includes a plurality of metering holes 44.

[0021] As shown in the enlarged view of Figure 3, metering holes 44 of nozzle 22 extend from inlet openings 48 to outlet openings 50 of body 46. In this embodiment of nozzle 22, the upper sac section is formed by a cylindrical wall 52 (instead of a conical wall 26). Nozzle 22 further includes an intermediate conical wall 28 which transitions into bottom wall 30. In this embodiment of the present disclosure, nozzle 22 includes a single row of eight holes 44, each of which extends from within nozzle 22 through body 46 of nozzle 22 as described below with reference to Figure 4.

[0022] As shown in Figure 4, openings 48 of holes 44 extend through each of cylindrical wall 52 and conical wall 28. In this embodiment, as depicted by the dotted lines corresponding to cylindrical wall 52 and conical wall 28, the walls 52, 28 intersect at an angular transition 32. Holes 44 are oriented such that a longitudinal axis 54 of holes 44 passes through walls 52, 28 below transition 32. Additionally, an uppermost point 56 of each opening 48 of each hole 44 is disposed above transition 32 and a lowermost point 58 of each opening 48 of each hole 44 is disposed below transition 32. Figure 5 shows nozzle 22 of Figures 3 and 4 with a needle valve 60 positioned therein and shown in closed position with an outer surface 62 of needle valve 60 engaging valve seat 24.

[0023] Figure 6 depicts another embodiment of a nozzle according to the present disclosure. As shown, nozzle 64 includes many of the same components as nozzle 22, and the same reference designations are used for like components. Nozzle 64 includes a conical wall 26 forming the upper sac section instead of the cylindrical wall 52 of nozzle 22.

[0024] As shown in Figure 7, openings 48 of holes 44 extend through each of conical wall 26 and conical wall 28. In this embodiment, as depicted by the dotted lines corresponding to conical wall 26 and conical wall 28, the walls 26, 28 intersect at an angular transition 32. Holes 44 are oriented such that a longitudinal axis 54 of holes 44 passes through walls 26, 28 below transition 32. Additionally, an uppermost point 56 of each opening 48 of each hole 44 is disposed above transition 32 and a lowermost point 58 of each opening 48 of each hole 44 is disposed below transition 32. Figure 8 shows nozzle 64 of Figures 6 and 7 with a needle valve 60 positioned therein and shown in closed position with an outer surface 62 of needle valve 60 engaging valve seat 24.

[0025] In another embodiment, holes 44 can all be positioned in the same plane. In still another embodiment, at least one opening 48 can at least partially extend from walls 26, 52 and/or at least one opening 48 can at least partially extend from intermediate conical wall 28 and/or bottom wall 30.

[0026] While this invention has been described as having an exemplary design, the present invention may be further modified within the spirit and scope of this disclosure. This application is therefore intended to cover any variations, uses, or adaptations of the invention using its general principles. Further, this application is intended to cover such departures from the present disclosure as come within known or customary practice in the art to which this invention pertains.

Claims

CLAIMS: What is claimed is:

1. A fuel injector nozzle, comprising:

a needle valve bore having a distal end;

an upper sac section extending from the distal end of the needle valve bore;

an intermediate sac section extending from the upper sac section;

a bottom sac section extending from the intermediate sac section, the upper sac section, intermediate sac section and bottom sac section defining a sac volume; and

a plurality of metering holes extending from the sac volume to outlet openings of the nozzle, the plurality of metering holes each including an inlet opening formed partially in the upper sac section and partially in the intermediate sac section.

2. The fuel injector nozzle of claim 1, wherein the upper sac section is formed by a cylindrical wall that defines a cylindrical upper volume of the sac volume.

3. The fuel injector nozzle of claim 1, wherein the upper sac section is formed by a conical wall that defines a conical upper volume of the sac volume.

4. The fuel injector nozzle of claim 1, wherein the intermediate sac section is formed by a conical wall that defines a conical intermediate volume of the sac volume.

5. The fuel injector nozzle of claim 1, wherein the upper sac section has a maximum diameter and the bottom sac section is formed by a bottom wall that has a radius which is greater than one-half the maximum diameter.

6. The fuel injector nozzle of claim 1, further comprising a transition radius between the upper sac section and the intermediate sac section.

7. The fuel injector nozzle of claim 1, further comprising a transition radius between the intermediate sac section and the bottom sac section.

8. The fuel injector nozzle of claim 1, wherein the plurality of metering holes each include a longitudinal axis that extends into the sac volume at a location below a transition between the upper sac section and the intermediate sac section.

9. The fuel injector nozzle of claim 3, wherein the conical wall of the upper sac section forms an angle with a longitudinal axis of the needle valve bore of up to 15 degrees.

10. The fuel injector nozzle of claim 4, wherein the conical wall of the intermediate sac section forms an angle with a wall forming the upper sac section of between 90 and 180 degrees.

11. The fuel injector nozzle of claim 5, wherein the bottom wall radius is at least 100 percent greater than one-half the maximum diameter of the upper sac section.

12. A fuel injector, comprising:

a needle valve having a tip and configured for reciprocal movement along a longitudinal axis between an opened and a closed position; and

a valve body including

a needle valve bore configured to receive the needle valve and having a seat that engages the needle valve tip when the needle valve is in the closed position and a distal end;

an upper sac section extending from the distal end of the needle valve bore;

an intermediate sac section extending from the upper sac section; a bottom sac section extending from the intermediate sac section, the upper sac section, intermediate sac section and bottom sac section defining a sac volume; and

a plurality of metering holes extending from the sac volume to outlet openings of the valve body, at least one of the plurality of metering holes including an inlet opening formed partially in the upper sac section and partially in the intermediate sac section.

13. The fuel injector of claim 12, wherein the upper sac section is formed by a cylindrical wall that defines a cylindrical upper volume of the sac volume.

14. The fuel injector of claim 12, wherein the upper sac section is formed by a conical wall that defines a conical upper volume of the sac volume.

15. The fuel injector of claim 12, wherein the intermediate sac section is formed by a conical wall that defines a conical intermediate volume of the sac volume.

16. The fuel injector of claim 12, wherein the upper sac section has a maximum diameter and the bottom sac section is formed by a bottom wall that has a radius which is greater than one -half the maximum diameter.

17. The fuel injector of claim 12, further comprising a transition radius between the upper sac section and the intermediate sac section.

18. The fuel injector of claim 12, further comprising a transition radius between the intermediate sac section and the bottom sac section.

19. The fuel injector of claim 12, wherein the plurality of metering holes each include a longitudinal axis that extends into the sac volume at a location below a transition between the upper sac section and the intermediate sac section.

20. The fuel injector of claim 12, wherein at least one of the plurality of metering holes includes an inlet opening formed partially in the intermediate sac section and partially in the bottom sac section.

21. A method, comprising :

providing fuel through a needle valve having a tip and configured for reciprocal movement along a longitudinal axis between an opened and a closed position;

routing the fuel into an upper sac section of a needle valve bore when the needle valve is in an opened position;

routing the fuel into an intermediate sac section extending from the upper sac section; routing the fuel into a bottom sac section extending from the intermediate sac section, the upper sac section, intermediate sac section and bottom sac section defining a sac volume; and routing the fuel through a plurality of metering holes extending from the sac volume to outlet openings of the valve body, the plurality of metering holes each including an inlet opening formed partially in the upper sac section and partially in the intermediate sac section.

22. The method of claim 21, wherein the upper sac section is formed by a conical wall that defines a conical upper volume of the sac volume.

23. The method of claim 21 , wherein the intermediate sac section is formed by a conical wall that defines a conical intermediate volume of the sac volume.

24. The method of claim 21, wherein the upper sac section has a maximum diameter and the bottom sac section is formed by a bottom wall that has a radius which is greater than one-half the maximum diameter.