NOZZLE FOR A FUEL INJECTOR

Abstract

The present disclosure relates to a nozzle for a fuel injector that comprises a pivotably symmetrical nozzle member having a hollow space for introducing a nozzle needle, a nozzle tip that is provided at a longitudinal end of the nozzle member, and at least one opening for discharging fuel, and a nozzle needle arranged in the hollow space for a selective blocking of a fuel inflow to the at least one opening, wherein the nozzle needle is designed as tubular in the region of the nozzle tip and is adapted to conduct fuel in the interior of the tubular region to the at least one opening.

Claims

1. A for a fuel injector comprising: a pivotably symmetrical nozzle member having a hollow space for introducing a nozzle needle; a nozzle tip that is provided at a longitudinal end of the nozzle member and has at least one opening for discharging fuel: and a nozzle needle arranged in the hollow space for selective blocking of a fuel supply to the at least one opening, wherein the nozzle needle is designed as tubular in a region of the nozzle tip and is adapted to conduct fuel in an interior of a tubular region toward the at least one opening.

2. The nozzle in accordance with claim 1, wherein a fluidic connection from the at least one opening to a reservoir for reception of pressurized fuel only runs through the tubular region of the nozzle needle.

3. The nozzle in accordance with claim 1, wherein the nozzle needle interrupts a fluidic connection of the at least one opening to a reservoir for receiving pressurized fuel by placing onto a seat surface of the nozzle member.

4. The nozzle in accordance with claim 1, wherein the nozzle tip has a conical elevated portion toward the hollow space for the nozzle needle, in the form of a right circular cone whose tip penetrates into the interior of the tubular region of the nozzle needle in a closed state of the nozzle.

5. The nozzle in accordance with claim 4, wherein the at least one opening for the discharge of fuel is adjacent to a jacket surface of the conical elevated portion, such that a fuel from the tubular region of the nozzle needle can flow out of the at least one opening in a straight line by a single deflection at the conical elevated portion in a state of the nozzle needle raised from the conical elevated portion.

6. The nozzle in accordance with claim 4, wherein the conical elevated portion and the nozzle needle are arranged coaxially to one another.

7. The nozzle in accordance with claim 5, wherein a region of the jacket surface of the conical elevated portion that surrounds the tip of the conical elevated portion represents a seat region for the nozzle needle that is contacted by the nozzle needle in a closed state of the nozzle.

8. The nozzle in accordance with claim 3, wherein the nozzle needle has rounded edges in its end section facing the nozzle tip.

9. The nozzle in accordance with claim 1, wherein the at least one opening for discharging fuel is not connected to a blind hole.

10. The nozzle in accordance with claim 7, wherein the at least one opening for discharging fuel is directly directed with its opening channel onto the seat region of the nozzle needle and/or starts directly from the seat region.

11. The nozzle in accordance with claim 1, wherein the tubular region of the nozzle needle extends up to its distal tip so that the nozzle needle has a tubular outlet there.

12. The nozzle in accordance with claim 1, wherein the tubular region of the nozzle needle is pivotally symmetrical.

13. The nozzle in accordance with claim 1, wherein an outer periphery of the nozzle needle is constant in its third facing the nozzle tip.

14. The fuel injector having a nozzle in accordance with claim 1.

15. The fuel injector in accordance with claim 14, further comprising a reservoir for receiving pressurized fuel, with a fluidic connection of the reservoir to the at least one opening for discharging fuel only extending through the interior of the tubular region of the nozzle needle.

16. The nozzle needle in accordance with claim 8, wherein the end section facing the nozzle tip-contacts the seat surface with the rounded edges.

17. The nozzle needle in accordance with claim 12, wherein the region of the nozzle needle facing the nozzle tip is rotationally symmetrical.

Description

BRIEF DESCRIPTION OF THE FIGURES

[0029] Further features, details of the disclosure will become clear with reference to the following description of the Figures. There are shown:

[0030] FIG. 1: a schematic view of a nozzle in accordance with the disclosure in a partially shown fuel injector;

[0031] FIG. 2: a schematic view of the distal end region of the nozzle in accordance with the disclosure; and

[0032] FIG. 3: a halved sectional view through a front region of a fuel nozzle in accordance with the prior art.

DETAILED DESCRIPTION

[0033] FIG. 1 shows a schematic view of a nozzle 1 in accordance with the disclosure in a partially shown fuel injector 20. The nozzle member 2 can be recognized here that has a nozzle tip 5 at its distal end that has a plurality of openings 6 for discharging fuel. 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 axes in accordance with the known principles for the raising and lowering of a nozzle needle 4 that are not restrictive for the present disclosure.

[0034] It can likewise be recognized that the nozzle needle 4 has a tubular region 7 that is adapted to conduct fuel from a proximal region of the nozzle 1 to a distal region (that is toward the tip) of the nozzle 1. The nozzle needle 3 can here be formed as a tubular needle nozzle. It is also conceivable that the tubular region 7 is formed by a bore that extends coaxially to the longitudinal direction of the nozzle needle 4.

[0035] FIG. 2 represents an enlarged view of an end region of the nozzle 1 in accordance with the disclosure.

[0036] It can be recognized that the nozzle tip 5 of the nozzle member 2 has a conical elevated portion 9 at the side facing the tubular region 7 of the nozzle need 4, the tip of said conical elevated portion 9 projecting into the interior of the tubular region 7.

[0037] In a closed state of the nozzle 1, the front surfaces of the nozzle needle 4 contact the conical elevated portion 9 at the so-called seat surface 10 and seal the interior of the nozzle needle 4 with respect to the at least one discharge opening 6. The front sides of the nozzle needle 4 are rounded here (cf. reference numeral 11) so that a small contact surface with the conical elevated portion 9 already achieves the desired sealing. It is additionally thereby possible to achieve a sealing in a reliable manner despite production tolerances.

[0038] If the nozzle needle 4 is raised from the seat surface 10, highly pressurized fuel can exit the nozzle 1 through the openings 6. In this process, the fuel is only deflected once, namely on the impact with the elevated portion 9, so that a little to absolutely no cavitation damage occurs.

[0039] FIG. 3 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—designed as solid and contacts an inner section of the nozzle member 2 in the region of the seat surface 10 in a peripheral region.

[0040] A blind hole 12 from which the openings 6 start for the exiting of fuel from 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.

[0041] Provision is additionally made in accordance with the prior art that the fuel flowing out through the openings 6 flows around the solid nozzle needle 4.