Injector for injecting a gaseous medium

Abstract

The present invention relates to an injector (1) for injecting a gaseous medium, in particular a gaseous fuel, preferably hydrogen, into a combustion chamber (20) of an internal combustion engine. The injector (1) comprises, inter alia, an axially movable valve-closing element (5) for opening and closing at least one opening at a sealing seat (7), an actuator (21) for actuating the valve-closing element (5), and a flow-influencing geometry (10) arranged downstream of the sealing seat (7) in terms of flow. According to the invention, the flow-influencing geometry (10) is designed in such a way that it is formed in an attachment body (8) downstream of the sealing seat (7), wherein the attachment body (8) has a hollow-cylindrical portion in the region of the sealing seat (7), which hollow-cylindrical portion is adjoined by an outflow region (16) with at least one outflow opening (17) which has an inner contour (9) and opens out in an end side (25) which faces the combustion chamber (20), wherein the end side (25) is equipped, in an inclined manner facing the outflow opening (17), with an at least partially encircling beveled region (26) which improves the flushing behaviour from the outflow opening (17).

Description

[0001] R. 414725

[0002] - 1 -

[0003] Description

[0004] title

[0005] Injector for injecting a gaseous medium

[0006] State of the art

[0007] The present invention relates to an injector for injecting a gaseous medium, in particular a gaseous fuel, into a combustion chamber of an internal combustion engine. Specifically, the invention relates to an injector with which hydrogen can be injected directly into the combustion chamber of a mixture-compressing, spark-ignition internal combustion engine.

[0008] Gas injectors are known in various designs from the prior art. Due to cost advantages and improved environmental compatibility, gaseous fuels have become increasingly popular recently. A problem compared to injectors for liquid fuels is that the amount of gas to be injected occupies a much larger volume than an equivalent amount of liquid fuel. This results in an increased stroke requirement for a closing element, which is usually actuated by a magnetic actuator. Designing the magnetic circuit with standard materials is very difficult or sometimes impossible due to the limited installation space. Materials with higher magnetic strength are very expensive and some are hazardous to health (e.g., FeCo). R. 414725

[0009] - 2 -

[0010] From DE 10 2021 206 438 A1, a gas nozzle for a gas valve is already known, comprising a nozzle body that is at least partially hollow and cylindrical, forming a sealing seat over which a gas flow path leads. The gas valve also has a movable valve closing element, partially integrated into the nozzle body, with an end section located outside the nozzle body and having a sealing contour that interacts with the sealing seat. Furthermore, the gas valve has a sleeve surrounding the nozzle body and the end section of the valve closing element, which limits the gas flow path downstream of the sealing seat. The gas flow path downstream of the sealing seat has a cross-sectional constriction to achieve the Venturi effect, in the region of which at least one intake channel opens. The sleeve is designed in the form of a blow-off cap that can be attached to the nozzle body.

[0011] Another injector for injecting a gaseous medium is also known from WO 2023 / 001384 A1. The blowing cap, which can be mounted on a nozzle body, has a sleeve-shaped base with a circumferential outer surface that transitions into a bottom section at the downstream end. The bottom section is designed such that at least one obliquely or asymmetrically blowing outlet opening is provided, and furthermore, the bottom section incorporates a flow-guiding section directed inwards towards the valve closing element, opposite to the flow direction, which deflects the flow of the gas to be blown out.

[0012] Disclosure of the invention

[0013] The injector according to the invention for injecting a gaseous

[0014] Medium, in particular a gaseous fuel in a combustion chamber of an internal combustion engine, with the features of claim 1, R. 414725

[0015] - 3 - in contrast, the advantage is that optimized gas flow in the injector is made possible by the geometric design of a flow control geometry downstream of the sealing seat, so that the internal flow of the gaseous medium is designed with as little loss as possible via the inner contour of the cap-shaped attachment body, so that the back pressure below, i.e. downstream of the valve closing element is reduced and at the same time the jet can be introduced into the combustion chamber in a targeted manner.

[0016] Furthermore, the forces acting on the valve closing element are reduced to a minimum in a special way. This reduces the magnetic force of an actuator that must be selected to keep the injector open, thus enabling the use of cost-effective materials in the actuator's magnetic circuit.

[0017] According to the invention, this is achieved by the injector having a valve closing element for opening and closing at least one opening at a sealing seat. The valve closing element is preferably an axially movable valve needle with a disc-shaped end section. Furthermore, an actuator for actuating the

[0018] A valve closing element is provided. The actuator is preferably a magnetic actuator, but can also be, for example, a mechanically or (piezo-)electrically operated actuator. More preferably, the actuator is configured to actively open and hold the valve closing element open by means of a stroke movement, while the valve closing element is closed by a spring force.

[0019] The flow control geometry, which is housed in particular in a cap-shaped attachment body, or in short, a blow cap, is characterized according to the invention in that the attachment body has a hollow cylindrical section in the area of ​​the sealing seat, to which an outflow area with at least one outflow opening R. 414725 having an inner contour is attached.

[0020] - 4 - connects, which opens into an end side facing the combustion chamber, wherein the end side facing the outflow opening is chamfered and equipped with a chamfered area that is at least partially circumferential.

[0021] This improves mixture formation and the purging behavior of any remaining residual gas, especially hydrogen, from the exhaust port. This effectively prevents pre-ignition of the hydrogen.

[0022] The dependent claims describe preferred embodiments of the invention.

[0023] The flow control geometry according to the invention is integrated into a relatively open mounting structure following the sealing seat. Such attachment bodies have the advantages of a very simple design and simple, easily reproducible manufacturing. Furthermore, no blocked dead volume is created inside the attachment body, which could adversely lead to premature pre-ignition.

[0024] The concept according to the invention allows for particularly high flexibility in the design of the spray pattern. The gas flow can be distributed very evenly throughout the entire combustion chamber, which improves mixture formation and increases efficiency.

[0025] It is particularly advantageous to design the chamfer area with a total chamfer angle of less than 180°, so that the chamfer forms, in a sense, a conically widening continuation of the outflow opening.

[0026] Preferably, the flushing behavior in the attachment body downstream of the valve closing element can be further improved by means of a flow shaper formed on the valve closing element and directed towards at least one discharge opening. R. 414725

[0027] - 5 -

[0028] The highly variable internal contour allows for very flexible use of sleeves or attachment bodies on injectors in various combustion chamber geometries of internal combustion engines.

[0029] The present invention is preferably used in injection systems that inject hydrogen directly into a combustion chamber. In particular, the injector is suitable for the direct injection of hydrogen into a combustion chamber of an internal combustion engine.

[0030] drawing

[0031] Preferred embodiments of the invention are described in detail below with reference to the accompanying drawing. The drawing shows:

[0032] Figure 1 shows a schematic sectional view of an injector for injecting a gaseous medium according to the prior art.

[0033] Figure 2 shows a sectional view of a known cap-shaped attachment body for an injector according to Figure 1.

[0034] Figure 3 shows a schematic sectional view of a cap-shaped attachment body for an injector for injecting a gaseous medium according to a first embodiment.

[0035] Figure 4 shows a schematic sectional view of a cap-shaped attachment body for an injector for injecting a gaseous medium according to a second embodiment, R. 414725

[0036] - 6 -

[0037] Figure 5 shows a schematic sectional view of a cap-shaped attachment body for an injector for injecting a gaseous medium according to a third embodiment.

[0038] Figure 6 shows a schematic sectional view of a cap-shaped attachment body for an injector for injecting a gaseous medium according to a fourth embodiment and

[0039] Figure 7 shows a schematic sectional view of a cap-shaped attachment body for an injector for injecting a gaseous medium according to a fifth embodiment.

[0040] Preferred embodiments of the invention

[0041] For a better understanding of the invention, the basic structure of an injector for injecting a gaseous medium and a known structure of a flow control geometry downstream of the valve seat are described below with reference to Figures 1 and 2.

[0042] Figure 1 shows a schematic cross-sectional view of the known injector 1 for injecting a gaseous medium. Since the invention relates to the flow control geometry 10, which is downstream of the valve seat 3, only this assembly of the known injector 1 will be described in detail here. For example, a magnetic actuator 21 is provided for actuating the injector 1, allowing the injector 1 to be controlled selectively. R. 414725

[0043] - 7 -

[0044] The injector 1 also has a nozzle body 2 which, on the injection side, forms a valve seat 3 at its end, for example, a conically shaped one, for an outwardly opening valve closing element 5, i.e., opening towards a combustion chamber 20. The valve closing element 5 is guided axially within the nozzle body 2 by a guide 18. Furthermore, the valve closing element 5 has an end section 6 in the form of a valve disc, which, corresponding to the valve seat 3, forms a sealing seat 7. Both sealing seat components, valve seat 3 and valve closing element 5, are made of metal. The geometric and material design is such that sufficient sealing is ensured during the operation of a hydrogen engine.In the event of a malfunction, a shut-off system (not shown here), installed upstream of injector 1 for safety reasons, would interrupt the supply of the gaseous medium, particularly the highly volatile hydrogen. The sealing contour of the end section 6 of the valve closing element 5 is, for example, rounded, while the valve seat 3 on the nozzle body 2 has a conical shape. However, other contours are also conceivable.

[0045] The nozzle body 2 and the end section 6 of the valve closing element 5 are surrounded by a sleeve 8 for jet shaping. In the following, and particularly with regard to the invention, a flow-control geometry 10 downstream of the sealing seat 7 is generally referred to. This can either be formed directly as a single piece on the nozzle body 2, which, however, requires considerable manufacturing effort, or be integrated into an additional component, which, with reference to the embodiments according to the prior art shown in Figures 1 and 2, is generally referred to as the sleeve 8. The sleeve 8 has a large overlap length with the nozzle body 2 in order to be able to securely and reliably fasten the sleeve 8. However, it can also be described as a cap-shaped attachment body 8, which, with reference to the embodiments of the invention, is also defined as the blow cap 8. R. 414725

[0046] - 8 -

[0047] The sleeve 8 and the end section 6 of the valve closing element 5 together define a gas flow path 4 into which at least one intake channel 15 formed in the sleeve 8 opens. Air from the environment can be drawn into the gas flow path 4 via one or more intake channels 15.

[0048] If the valve closing element 5 is in an open position lifted from the valve seat 3, the gas flow path 4 then leads via the valve seat 3 into an interior of the sleeve 8, which is characterized by a special shape with an inner contour 9. Starting from a cylindrical section 11 of the sleeve 8 and following the flow direction of the valve closing element 5, a reduction in cross-section occurs at a large axial distance from the valve closing element 5 in a central cylindrical axial region 13 of the flow control geometry 10 of the sleeve 8, whereby the narrowing is achieved via a conically extending section 12 in the inner contour 9 of the sleeve 8. The intake channels 15 open precisely into the inner contour 9 of the sleeve 8 in the central axial region 13.

[0049] The reduction in cross-section within the gas flow path 4 creates the effect that, as the gas flows out through the gas flow path 4 towards an outlet 19, ambient air is drawn into the gas flow path 4 via the intake channels 15 (“Venturi effect”). This means that air is mixed with the gas even before it reaches the outlet 19, thus improving the mixture preparation.

[0050] The reduction in cross-section is reversed by the fact that the central axial area 13 is followed by a conically extending section 1, in this case widening conically in the flow direction, with this section 1 extending to the outlet 19. The reduction in cross-section in the inner contour 9 of the sleeve 8 is thus intended to achieve the Venturi effect, which is optimized together with the air mixture. R. 414725

[0051] - 9 -

[0052] Experience has shown that such a solution, or other known geometries or internal contours of cap-shaped attachment bodies, does not achieve sufficiently good results regarding the introduction of the jets into the combustion chamber 20, nor their guidance and shaping for optimal combustion. Furthermore, there is a risk of engine pre-ignition due to insufficient purging, particularly of the hydrogen remaining in the attachment body.

[0053] Therefore, the object of the invention is to provide an inner contour 9 of a cap-shaped attachment body 8 with a flow-influencing geometry 10 downstream of the sealing seat 7, with which optimal combustion results are achieved due to the flow guidance according to the invention, wherein an improved purge behavior of hydrogen remaining in the attachment body 8 is to be achieved by means of an outer contouring of the attachment body 8 in conjunction with the flow-influencing geometry 10 defined by the inner contour 9 in order to avoid pre-ignition.

[0054] Injection systems for the direct injection of a gaseous medium, in particular hydrogen, but also CNG, methane, ammonia, or mixtures of the aforementioned gases, have the task of precisely controlling the metering and the injection direction of the gas jet(s) into the combustion chamber 20 via injection valves or, more generally, injectors 1. For this purpose, corresponding sleeves or injection caps 8 can be used on the injector 1, as previously explained. Furthermore, injection systems for the (hydrogen)-

[0055] Direct injection inherently requires a large stroke of the valve needle with the valve closing element 5. Designing the magnetic circuit (magnetic actuator 21) with known standard materials is very difficult or even impossible due to the limited installation space. Materials with higher magnetic force and thus better B / H characteristics are very suitable. R. 414725

[0056] - 10 - expensive and in some cases also harmful to health (e.g., FeCo). Therefore, improved beam guidance should also be used to reduce magnetic force.

[0057] The core of the invention lies in shaping the internal flow of the gaseous medium with minimal loss via the inventive inner contour 9 of the cap-shaped attachment body 8, so that the back pressure located below, i.e., downstream of the disc-shaped end section 6 of the valve closing element 5, is reduced and, at the same time, the jet can be directed precisely into the combustion chamber 20. This defined inner contour 9 is particularly aimed at improving mixture formation. Due to the highly variable contouring of the inner contour 9, a very flexible use of sleeves or attachment bodies 8 on injectors 1 in various combustion chamber geometries of internal combustion engines is enabled.In particular, in combination with an external contour 9 provided in at least one outflow opening 17, which is downstream of the internal contour 9 in terms of flow characteristics and is located on an end face 25 facing the combustion chamber 20 and is chamfered with a chamfered area 26 that is at least partially circumferential, the scavenging behavior from the outflow opening 17 can be significantly improved. The chamfered area 26 does not necessarily have to be exactly inclined, i.e., exactly conical, but can also have a large radius and thus be slightly convex or concave.

[0058] Overall, the optimized jet-shaping cap and needle geometry allows for improved charge movement with increased purging of residual gas and hydrogen in the internal volume of the attachment body 8. This results in a robustness measure against pre-ignition even with increased seat leakage for the hydrogen injector during engine operation.

[0059] The following describes, with reference to Figures 3 to 7, injectors 1 with flow-optimized valve seat 3 according to the invention. R. 414725

[0060] - 11 - downstream flow-influencing geometries 10 according to preferred embodiments of the invention are described in detail. As mentioned previously, these flow-influencing geometries 10 can be formed directly as a single piece on the nozzle body 2 or, as shown in all figures, integrated into an additional component, which can be referred to as a cap-shaped attachment body 8 (or simply blow cap 8). The attachment body 8 will typically have a significantly shorter overlap with the nozzle body 2 than shown in Figure 1. The only essential requirement is a secure and reliable attachment to the nozzle body 2, enabling perfect and axially parallel alignment with the injector 1. Known joining methods such as pressing, welding, brazing, gluing, or combinations thereof can be used.

[0061] Figure 3 shows a first embodiment of a flow-control geometry 10 located downstream of the valve seat 3 in a cap-shaped attachment body 8 and generated by an inner contour 9 according to the invention. The valve closing element 5 with its disc-shaped end section 6 is shown schematically and in a highly simplified cross-section as a chamfered rectangle. However, the end section 6 can also have further chamfers or rounded edges on its outer contour or be completely rectangular.

[0062] The injection-side end with the flow-influencing geometry 10 of the injector 1 is arranged facing the combustion chamber 20 of the internal combustion engine. The flow-influencing geometry 10, generated by the inner contour 9 according to the invention and the outer chamfered area 26, has a key geometric characteristic that primarily generates a deflection of the gas flow radially inwards in a downstream direction within the attachment body 8, in order to then direct the gas to be expelled, R. 414725

[0063] - 12 - in particular hydrogen, into which at least one outflow opening 17 is discharged. It should be expressly emphasized at this point that more than one outflow opening 17 can also be provided. However, the measures according to the invention are particularly effective with the outer chamfered area 26 if, as shown in the exemplary embodiments, only a single outflow opening 17 is provided. In the case of the example shown in Figure 3, the outflow opening 17 is cylindrically parallel to the axis and coaxial.

[0064] For all described and shown embodiments according to Figures 3 to 7, it generally applies that the flow control geometry 10 is formed downstream of the sealing seat 7 in an attachment body 8, wherein the attachment body 8 has a hollow cylindrical section in the area of ​​the sealing seat 7, to which an outflow area 16 with at least one outflow opening 17 having the inner contour 9 is connected, which opens into an end side 25 facing the combustion chamber 20, wherein the end side 25 facing the outflow opening 17 is chamfered and equipped with an at least partially circumferential chamfer area 26, which improves the scavenging behavior from the outflow opening 17.

[0065] The thin-walled sleeve contour of the overlap area for attachment to the nozzle body 2 initially continues largely in the downstream direction, although variations in wall thickness along the axial length of the attachment body 8 are conceivable. In the axially subsequent outflow area 16, a significantly greater wall thickness is provided, depending on the number of outflow openings 17.

[0066] The flow control geometry 10 generated by the inner contour 9 has several essential aspects and geometric specifications. Downstream of the valve closing element 5, the inner contour 9 of the attachment body 8 is shaped such that a tapered, R. 414725

[0067] - 13 - in particular, a conically shaped section adjoins the conical section, which ensures a significant narrowing of the inner contour 9 over a short axial length, thus advantageously contributing to the desired optimized flow result. The jet guidance from the sealing seat 7 is achieved via the inner contour 9 in the conically shaped section, which is designed with an inclination angle of 60° > a > 30°, preferably with an inclination angle of > 45°. With this relatively large angle of the conically shaped section, a strong radially inward-directed flow component is generated over a very short axial length, so that in this area, immediately downstream of the valve closing element 5, flow guidance advantageously occurs in the form of an "S-curve". Instead of the conical shape of the section, this section can also be slightly convex or slightly concave.The inner contour 9 ensures that a supercritical flow is guaranteed and that back pressures below the valve closing element 5 are limited.

[0068] The end face 25 of the attachment body 8 is understood to be its downstream end face, which slopes towards the outflow opening 17 and is directed towards the combustion chamber 20. In the example of Figure 3 with a coaxial outflow opening 17, this transitions into a chamfered area 26, which spans a total chamfer angle α of 45° to 170°, and preferably a chamfer angle α of 100° to 170°.

[0069] Figure 4 shows a schematic sectional view of a cap-shaped attachment body 8 for an injector 1 for injecting a gaseous medium according to a second embodiment. This differs from the example shown in Figure 3, in particular, in that the outflow opening 17 is inclined. Accordingly, the radial width of the chamfer area 26 is smaller. However, the chamfer area 26 can also extend over a total chamfer angle of 45° to R. 414725

[0070] - 14 -

[0071] 170° can be defined, in particular preferably via a chamfer angle a of 100° to 170°.

[0072] The chamfered area 26 of the downstream end face 25 of the attachment body 8 is defined in each case such that the outflow opening 17 opens at a greater than a right angle in cross-section, since the chamfered area 26, with a total chamfer angle α of less than 180°, ultimately always forms a conically widening continuation of the outflow opening 17. This at least partially circumferential chamfered area 26 ensures an improvement in the scavenging behavior of the gas injected into the combustion chamber 20 from the outflow opening 17.

[0073] Such attachment bodies 8 have the advantages of a very simple design and simple, easily reproducible manufacturing. Furthermore, no blocked dead volume is created inside the attachment body 8, which could adversely lead to premature pre-ignition. Arrows 4 indicate the gas flow, while arrows 40, pointing in the opposite direction into the attachment body 8, indicate a purge flow from the combustion chamber 20, whereby the purge flow 40 effectively and additionally prevents pre-ignition. The chamfered area 26 particularly favorably facilitates this improved purge behavior.

[0074] Figures 5 and 6 each show a cap-shaped attachment body 8, in which a modified valve closing element 5 is present. The end section 6 of this modified element has an additional flow shaper 27, which, unlike the actual disc-shaped element, has a downstream contour. The flow shaper 27 can, for example, be a needle tip formed centrally on the valve closing element 5, either conically or with a stepped conical shape, with a flow angle of, for example, 10° to 40°, or cylindrically shaped. The diameter of the R. 414725

[0075] - 15 -

[0076] The flow former 27 at the upstream end can be equal to, but also larger or smaller (Figures 5 and 6) than the diameter of the valve needle shaft. The flow former 27 can, for example, also extend from the radially outer contour of the disc-shaped valve closing element 5. The embodiments shown in Figures 5 and 6 differ only in that the base of the valve disc of the end section 6 of the valve closing element 5 is either largely flat (Figure 5) or has an annular trough-like depression (Figure 6), which can deflect the purge flow 40 particularly effectively to further prevent pre-ignition. Instead of a circumferential depression of the "flow rocker," flow grooves can also be provided on the base of the valve disc of the end section 6 of the valve closing element 5 to stabilize the tumble flows.

[0077] In all the aforementioned cases, for the chamfer area 26, the overall angle of the chamfer a is between 45° and 170°, and preferably a chamfer angle a of 100° to 170°.

[0078] Figure 7 shows a schematic sectional view of a cap-shaped attachment body 8 for an injector 1 for injecting a gaseous medium according to a fifth embodiment. This differs only slightly from the first embodiment shown in Figure 3.

[0079] The end face 25 of the attachment body 8, as its downstream end face, has a transition with a radius R, i.e., facing the outflow opening 17, there is not only a chamfered section directed towards the combustion chamber 20, but also, for example, a radially outer section that runs at a right angle to the longitudinal axis of the valve. In the example of Figure 7 with a coaxial outflow opening 17, the outflow opening 17 also transitions into a chamfered area 26, R. 414725

[0080] - 16 - which spans a total chamfer angle a of 45° to 170°, in particular preferably a chamfer angle a of 100° to 170°. The radius R at the transition on the end face 25 is, for example, between 0.5 mm and 2.0 mm. The radius R can ensure improved inflow of the flushing flow 40 into the inner contour 9.

[0081] The geometries of figures 3 and 5 to 7 on the end side 25 can also be combined with an inclined outflow opening 17 according to figure 4.

[0082] The design features described above define an optimized attachment body 8 as a largely open blow cap. The advantages of the illustrated embodiments are that a targeted jet guidance downstream of the sealing seat 7 is achieved via the geometry of the inner contour 9 in conjunction with the subsequent chamfered area 26, while simultaneously ensuring the purge of the gaseous medium, in particular hydrogen.

[0083] In addition to the optimized jet guidance made possible by the attachment body 8 according to the invention, further advantages of the attachment body 8 designed in this way are the increased strength and improved thermal conductivity. By avoiding back pressure downstream of the sealing seat 7, a high degree of pressure independence prevails in this area, so that optimized flushing from the attachment body 8 is possible at all times.

[0084] The concept according to the invention allows for particularly high flexibility in the design of the spray pattern. The gas flow can be distributed very evenly throughout the entire combustion chamber 20, which improves mixture formation and increases efficiency.

Claims

R. 414725 - 17 - Claims 1. Injector (1) for injecting a gaseous medium, in particular a gaseous fuel, preferably hydrogen, into a combustion chamber (20) of an internal combustion engine, comprising an axially movable valve closing element (5) for opening and closing at least one opening on a sealing seat (7), an actuator (21) for actuating the valve closing element (5), and a flow-influencing geometry (10) downstream of the sealing seat (7), characterized in that the flow-influencing geometry (10) is formed downstream of the sealing seat (7) in an attachment body (8), wherein the attachment body (8) has a hollow cylindrical section in the region of the sealing seat (7), to which an outflow region (16) with at least one outflow opening (17) having an inner contour (9) is connected, which opens into an end face (25) facing the combustion chamber (20),wherein the end side (25) facing the outflow opening (17) is chamfered and equipped with at least a partially circumferential chamfered area (26) which improves the flushing behavior from the outflow opening (17).

2. Injector according to claim 1, characterized in that the chamfer area (26) of the downstream end side (25) of the attachment body (8) is defined such that the outflow opening (17) opens at a greater than a right angle in cross-section. R. 414725 - 18 - 3. Injector according to claim 1 or 2, characterized in that the chamfer area (26) with a total chamfer angle a less than 180° forms a conically widening continuation of the outflow opening (17).

4. Injector according to one of the preceding claims, characterized in that the total angle a of the chamfer area (26) is 45° to 170°, in particular preferably between 100° and 170°.

5. Injector according to one of the preceding claims, characterized in that the chamfered area (26) completely surrounds the downstream end side (25) of the attachment body (8).

6. Injector according to one of the preceding claims, characterized in that the outflow opening (17) in the outflow area (16) of the attachment body (8) is either coaxial or inclined.

7. Injector according to one of the preceding claims, characterized in that the valve closing element (5) has a flow former (27) directed towards at least one outflow opening (17).

8. Injector according to one of the preceding claims, characterized in that the flow control geometry (10) downstream of the sealing seat (7) is realized in a blow cap (8).

9. Injector according to one of the preceding claims, characterized in that the cap-shaped attachment body (8) can be attached to a spray-side end of the injector (1), in particular to a nozzle body (2).

10. Injector according to one of the preceding claims, characterized in that the valve closing element (5) is part of an axial R. 414725 - 19 - movable valve needle, wherein the valve closing element (5) has an end section (6) which is largely disc-shaped.

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