NOZZLE FOR A FUEL INJECTOR

Abstract

A nozzle for a fuel injector the nozzle having a pivotably symmetrical nozzle member with a hollow space for introducing a nozzle needle, a nozzle tip at a longitudinal end of the nozzle member, at least one opening channel extending in a straight line for the discharge of fuel, and a nozzle needle arranged in the hollow space for selectively blocking an fuel inflow to the at least one opening channel. The nozzle is characterized in that the at least one opening channel has a center axis that is skewed with respect to the longitudinal axis of the nozzle member.

Claims

1. A nozzle for a fuel injector comprising: a pivotably symmetrical nozzle member having a hollow space for introducing a nozzle needle; a nozzle tip at a longitudinal end of the nozzle member, wherein the nozzle member has at least one opening channel extending in a straight line for discharging fuel: and a nozzle needle arranged in the hollow space, wherein the nozzle needle is configured to selectively block of a fuel supply to the at least one opening channel, wherein the at least one opening channel has a center axis that is skewed with respect to a longitudinal axis of the nozzle member.

2. The nozzle in accordance with claim 1, wherein a plurality of opening channels are provided, wherein each opening channel of the plurality of opening channels has a center axis that is respectively skewed with respect to the longitudinal axis of the nozzle member and wherein each of the plurality of center axes are also skewed with respect to one another.

3. The nozzle in accordance with claim 2, wherein inflow openings of the plurality of opening channels and squirt openings of the plurality of opening channels are each arranged on a circle that defines an inner surface that is perpendicular to the longitudinal axis of the nozzle member, and wherein the inflow openings are arranged equidistantly from one another and/or the squirt openings are arranged equidistantly from one another.

4. The nozzle in accordance with claim 3, wherein the circle on which the inflow openings are arranged has a smaller diameter than the circle on which the squirt openings are arranged.

5. The nozzle in accordance with claim 2, wherein the hollow space of the nozzle member tapers in a funnel form at an end section facing the at least one opening channel and has a jacket surface in a shape of a truncated cone standing on its head.

6. The nozzle in accordance with claim 5, wherein the funnel form end section defines a circle at the tapered end to which an associated inflow opening of the at least one opening channel is adjacent.

7. The nozzle in accordance with claim 5, wherein, the funnel form end section defines a circle at the tapered end whose inner surface is planar or whose inner surface rises in a direction of the hollow space.

8. The nozzle in accordance with claim 7, wherein the inner surface defined by the circle at the tapered end of the funnel form end section has a conical elevated portion, a cylindrical elevated portion, and/or a frustoconical elevated portion toward the hollow space has an axis of rotation that is identical to the longitudinal axis of the nozzle member.

9. The nozzle in accordance with claim 1, wherein the nozzle needle has a distal end contour that is adapted to a geometry of a distal end section of the nozzle member, and has a shape complementary thereto.

10. The nozzle in accordance with claim 5, wherein the nozzle needle has a frustoconically tapering end section whose angle of inclination, that is an angle from the jacket surface to the cone axis, is greater than that of the funnel form end section of the nozzle member.

11. The nozzle in accordance with claim 1, wherein a space from which the at least one opening channel starts is provided beneath the nozzle needle between the nozzle needle and the nozzle member in a closed state of the nozzle in which the nozzle needle contacts the nozzle member at a seat surface.

12. The nozzle in accordance with claim 10, wherein the center axes of the plurality of opening channels define a one sheet hyperboloid whose reference line is identical to the longitudinal axis of the nozzle member.

13. The nozzle in accordance with claim 12, wherein the angle of inclination of the opening channels, that is the angle of inclination of all generatrices of the one sheet hyperboloid differs by less than 45°, or less than 25°, or less than 10°, or by less than 4°, from a complementary angle of the angle of inclination of the funnel form end section, that is the angle from the jacket surface to a conical axis.

14. The nozzle in accordance with claim 1, wherein the hollow space is a blind hole, with a separate component.

15. A fuel injector having a nozzle, wherein the nozzle comprises: a pivotably symmetrical nozzle member having a hollow space for introducing a nozzle needle; a nozzle tip at a longitudinal end of the nozzle member, wherein the nozzle member has at least one opening channel extending in a straight line for discharging fuel; and a nozzle needle arranged in the hollow space, wherein the nozzle needle is configured to selectively block a fuel supply to the at least one opening channel, wherein the at least one opening channel has a center axis that is skewed with respect to the longitudinal axis of the nozzle member.

16. The nozzle in accordance with claim 14, wherein the separate component of the hollow space is a sphere arranged at a base of the blind hole to produce a structure projecting into the hollow space.

Description

BRIEF DESCRIPTION OF THE FIGURES

[0029] The disclosure additionally relates to a fuel injector having a nozzle in accordance with one of the variants described above.

[0030] Further features, details of the disclosure will become clear with reference to the following description of the Figures. There are shown:

[0031] FIG. 1A: a sectional view along an axis A-A of FIG. 1B of the nozzle in accordance with an embodiment of the disclosure;

[0032] FIG. 1B: a plan view of the nozzle in accordance with the disclosure;

[0033] FIG. 2A: a sectional view along an axis B-B through the first embodiment of the nozzle as shown in FIG. 2B;

[0034] FIG. 2B: a plan view of an embodiment of the nozzle in accordance with the disclosure;

[0035] FIG. 3: a sectional view with hidden elements showing through of a second embodiment of the nozzle in accordance with the disclosure;

[0036] FIG. 4A: a sectional view with hidden elements showing through of a third embodiment of the nozzle in accordance with the disclosure;

[0037] FIG. 4B: a sectional view with hidden elements showing through of a fourth embodiment of the nozzle in accordance with the disclosure;

[0038] FIG. 5A: a sectional view through the center axis of the nozzle with hidden elements showing through a further embodiment of the nozzle in accordance with the disclosure;

[0039] FIG. 5B: a plan view of the nozzle member of FIG. 5A with hidden elements showing through;

[0040] FIG. 6: a single sheet hyperboloid with the associated family of straight lines; and

[0041] FIG. 7: a halved sectional view through a distal region of a fuel nozzle in accordance with the prior art.

DETAILED DESCRIPTION

[0042] FIGS. 1A-B shows schematic views of the distal end region of a nozzle 1 in accordance with the disclosure. The nozzle member 2 can be recognized here that has a nozzle tip 5 at its distal end that has a plurality of opening channels 6 for discharging fuel (partially hidden). The nozzle member 2 here has a hollow space 3 for receiving a nozzle needle 4 that is movably received therein. The nozzle needle 4 can be moved along its longitudinal axis in accordance with the known principles for the raising and lowering of a nozzle needle 4 that are not restrictive for the present disclosure.

[0043] In a closed state of the nozzle 1, a tapering distal end section of the nozzle needle 4 lies on a seat surface 7 such that a fluid connection from an opening channel 6 arranged beneath the seat surface 7 to a space fillable with fuel above the seat surface 7 is interrupted. If the nozzle needle 4 contacts the seat surface 7 of the nozzle member, the nozzle 1 is in a closed state.

[0044] If, in contrast, the nozzle needle 4 is raised from the seat surface 7, there is an outflow of fuel from the opening channels 6.

[0045] It can furthermore be seen from FIG. 1A that the base of the blind hole-like hollow space 3 has a conical elevated portion 34 that projects into the hollow space 3 and that cooperates with a tip of the nozzle needle 4 shaped complementary thereto. The nozzle needle 4 has a W shape at its distal end in the section through the center axis of the nozzle 1 shown in FIG. 1A. The two outer strokes of the W shape here contact the seat surface 7, whereas the two inner strokes of the W shape cooperate with the conical elevated portion of the base of the blind hole.

[0046] The hollow space 3 of the nozzle member 2 has a cylindrical section 31 which the funnel-like end section 31 adjoins. The surface connecting the tapering end can adopt different designs in accordance with the disclosure.

[0047] FIG. 1B shows a plan view of the nozzle member of FIG. 1A in which hidden elements such as the opening channels 6 show through. It can be recognized that the opening channels 6 that extend in a straight line and that can be produced, for example, by bores, are skewed with respect to the longitudinal axis of the nozzle member 2. It can additionally be recognized that the inlet openings of the opening channels are adjacent to the jacket surface of a truncated cone 32, 33.

[0048] FIG. 2A is a second sectional view of the first embodiment of the disclosure. The sectional line B-B can here be seen from FIG. 2B that indicates a section along an opening passage 6.

[0049] It can thus be seen in FIG. 2A that the opening channel is arranged at the base of the blind hole or hollow space 3 directly adjacent to the jacket surface of the funnel-like end section 32, 33 at the same inclination as the funnel-like end section so that an outflowing fluid does not have to perform any deflection on the transition from the hollow space 3 into the opening channel 6.

[0050] An inflow opening into the opening channel 6 is characterized by the reference numeral 61, whereas the reference numeral 62 shows an outlet opening.

[0051] It can be seen from FIG. 2B that there is a total of eight different opening channels that are skewed both with respect to one another and with respect to the longitudinal axis of the nozzle.

[0052] In this respect, however, the inflow openings 61 and/or the outlet openings 62 of the respective opening channels 6 are all disposed on a circle 33.

[0053] FIG. 3 shows a sectional view of the nozzle member 2 identical to that of FIG. 1A, with, in contrast to the preceding views, the hidden opening channels 6, that can actually not be seen in a sectional view, being shown for a better understanding of the disclosure.

[0054] FIGS. 4A and B show a further embodiment of the disclosure that, in contrast to the first embodiment shown in FIGS. 1 to 3, differs in its design of the distal tip section.

[0055] The base of the hollow space 3 or of the blind hole is now no longer provided with a conical elevated portion projecting into the hollow space 3, but rather adopts a design different therefrom. In the present case, the elevated portion is represented by a relatively flat truncated cone 342. The distal tip of the nozzle needle 4 also has a shape complementary thereto.

[0056] FIGS. 4A and B show a further embodiment of the disclosure that, in contrast to the preceding embodiments, differs in its design of the distal tip section.

[0057] The base of the hollow space 3 or of the blind hole is now no longer provided with a conical elevated portion projecting into the hollow space 3, but rather adopts a design different therefrom. In the present case, the elevated portion is formed by a flat plane 341. The distal tip of the nozzle needle 4 also has a shape complementary thereto and is now likewise planar. The hollow space 3 in this embodiment has a flat base.

[0058] FIGS. 5A and 5B show a sectional view through the center axis of the nozzle or a plan view into the hollow body 3 of the nozzle member 2. The embodiment shown here corresponds to the previous embodiment, with a few modifications with respect to the opening channels.

[0059] It can be recognized that the outlet openings 62 of the opening channels 6 are arranged on a circle that has a greater radius than the circle on which the inflow openings 61 are arranged. It is thereby achieved that a larger jet angle is covered on discharging fuel into a combustion space.

[0060] FIG. 6 shows a single sheet hyperboloid that is produced in that a straight line 12 skewed with respect to the reference line 11 is rotated about the reference line 11. The skewed straight lines 11 stand on a circular ring 14, 15 on a normal plane to the reference lines 11.

[0061] In the present disclosure, the arrangement of the straight-line opening channels with their respective center axes can adopt the shape of a single sheet hyperboloid. It is naturally not necessary here that the inlet and outlet openings of the opening channels are arranged on circles having the same diameters. They can, for example, be different as shown in FIG. 5A.

[0062] FIG. 7 shows a nozzle 1 in its region of the tip in accordance with the prior art. The nozzle member 2 has a cutout 8 into which a nozzle needle 4 is introduced. This nozzle needle 4 is—unlike in accordance with the disclosure—not provided with a planar distal end section or even with an inwardly projecting arch.

[0063] A blind hole 12 from which the openings 6 start for the outlet of fuel from the nozzle 1 radially to the longitudinal axis of the nozzle 1 is provided beneath the seat surface 10. A multiple deflection of fuel is necessary due to this design, which promotes the occurrence of cavitation damage.