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, among other things, 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 control geometry (10) downstream of the sealing seat (7), wherein the flow control geometry (10) is designed such that it 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 two outflow openings (17) having an inner contour (9) is connected, which open into an end side (25) facing the combustion chamber (20).According to the invention, the outflow area (16) downstream of the sealing seat (7) has a trough-like section (22) to which the at least two outflow openings (17) are connected downstream, wherein an insert part (30) between the at least two outflow openings (17) acts as a jet splitter and performs jet shaping of the individual gas flow paths (4) in the outflow openings (17).

Description

State of the art 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. 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). 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. 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. Disclosure of the invention The injector according to the invention for injecting a gaseous medium, in particular a gaseous fuel, into a combustion chamber of an internal combustion engine, with the features of claim 1, has the advantage that an optimized gas flow in the injector is enabled 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 located 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. 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. 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 is provided for actuating the valve closing element. The actuator is preferably a magnetic actuator, but can also be, for example, a mechanically or (piezo-)electrically operated actuator. 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. 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 two outflow openings, each having an inner contour, is connected, in particular openings in an end side facing the combustion chamber, wherein the outflow area has a trough-like section downstream of the sealing seat, to which the at least two outflow openings are connected downstream, wherein an insert part between the at least two outflow openings acts as a jet splitter and performs jet shaping of the individual gas flow paths in the outflow openings. In this way, mixture formation and the purging behavior of remaining residual gas, especially hydrogen, from the exhaust port are improved. This effectively prevents pre-ignition of the hydrogen. Optimal combustion results can be achieved with the flow control geometry provided according to the invention, through the corresponding internal contour design and the resulting flow guidance. This also allows for maximum flexibility in the jet design. Furthermore, no blocked dead volume is created inside the attachment body, which could adversely lead to premature pre-ignition. The dependent claims describe preferred embodiments of the invention. The inventive attachment bodies offer the advantages of an extremely wide variety of variants and a very high degree of flexibility with regard to the shaping of the insert components integrated into the attachment body. Furthermore, simple and easily reproducible manufacturing is possible. The attachment body is preferably manufactured using MIM (Metal Injection Molding) or 3D printing, in particular 3D metal printing. The insert is a self-contained component integrated into the mounting body. Advantageously, the insert has an axially elongated shape resembling a contoured pin or bolt. It is positioned along a central axis of the mounting body in a central installation position. The insert is designed to be symmetrically arranged coaxially, which is particularly advantageous and enables cost-effective mass production. 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. 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. 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. drawing Preferred embodiments of the invention are described in detail below with reference to the accompanying drawing. In the drawing: Fig. 1 is a schematic sectional view of an injector for injecting a gaseous medium according to the prior art; Fig. 2 is a sectional view of a known cap-shaped attachment body for an injector according to Fig. 1; Fig. 3 is a schematic sectional view of a cap-shaped attachment body for an injector for injecting a gaseous medium according to a first embodiment; Fig. 4 is a schematic sectional view of a cap-shaped attachment body for an injector for injecting a gaseous medium according to a second embodiment; Fig. 5 is a schematic sectional view of a cap-shaped attachment body for an injector for injecting a gaseous medium according to a third embodiment.Fig. 6 a schematic sectional view of a cap-shaped attachment body for an injector for injecting a gaseous medium according to a fourth embodiment, Fig. 7 a schematic sectional view of a cap-shaped attachment body for an injector for injecting a gaseous medium according to a fifth embodiment, Fig. 8 a schematic sectional view of a cap-shaped attachment body for an injector for injecting a gaseous medium according to a sixth embodiment, Fig. 9 a schematic sectional view of a cap-shaped attachment body for an injector for injecting a gaseous medium according to a seventh embodiment, and Fig. 10 a schematic sectional view of a cap-shaped attachment body for an injector for injecting a gaseous medium according to an eighth embodiment. Preferred embodiments of the invention 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 Fig. 1 and Fig. 2. 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 in a targeted manner. 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. 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 according to the invention, is also defined as the blow cap 8. 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. 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. 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, air from the surroundings 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. The reduction in cross-section is reversed by the fact that the central axial area 13 is followed by a conically extending section 14, in this case widening conically in the flow direction, with this section 14 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. 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. 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 located downstream of the sealing seat 7, with which optimal combustion results are achieved due to the inventive inner contour design and the resulting flow guidance. Maximum flexibility in the spray pattern design is desirable. Injection systems for the direct injection of a gaseous medium, especially 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 (hydrogen) direct injection inherently require 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 expensive and, in some cases, also hazardous to health (e.g., FeCo).Therefore, improved beam guidance should also be used to achieve a reduction in magnetic force. The core of the invention lies in shaping the internal flow of the gaseous medium with minimal loss via the inventive internal 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, several gas jets can be selectively introduced into the combustion chamber 20 in a desired, jet-shaped manner. This defined internal contour 9 is aimed in particular at improved mixture formation and optimized jet penetration in the combustion chamber 20. Due to the highly variable contouring of the internal 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. Overall, the optimized jet-shaping cap 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. The following section describes injectors 1 with flow-influencing geometries 10 according to the invention, which are located downstream of the valve seat 3, in preferred embodiments of the invention, with reference to Figures 3, 4, 5, 6, 7, 8, 9 to 10. These flow-influencing geometries 10 are integrated into a cap-shaped attachment body 8 (hereinafter referred to as the blow cap 8). The attachment body 8 typically has 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. Attachment with a snap ring is also conceivable. Figure 3 shows a first embodiment of a flow-influencing 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. 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 internal contour 9 according to the invention has a key geometric characteristic that primarily deflects the gas flow radially inwards in a downstream direction within the attachment body 8, in order to then discharge the gas to be blown out, in particular hydrogen, into at least two outlet openings 17. For the described and illustrated embodiments according to Figs. 3, 4, 5, 6, 7, 8, 9 to 10, it generally applies that the attachment body 8 has a hollow cylindrical section in the region of the sealing seat 7, to which an outflow area 16 with at least two outflow openings 17 is connected. These openings generally open onto the outer contour of the attachment body 8, in particular onto an end face 25 facing the combustion chamber 20. According to the invention, the outflow area 16 has a trough-like section 22 immediately downstream of the sealing seat 7. Due to the specific inner contour 9, the medium flowing into the attachment body 8 from the sealing seat 7 is guided stably, and the flow velocity is largely maintained up to the inlet cross-sections of the outflow openings 17.Such an adaptation, in conjunction with different shapes of outflow openings 17, enables targeted shaping of the gas jets as well as optimized mixture formation in the combustion chamber 20. The resulting increased flow rate also reduces the back pressure in the internal volume of the attachment body 8, thus improving scavenging and reducing the forces acting on the underside of the end section 6 of the valve closing element 5. 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 the tapered, in particular conical or trough-like section 22 follows, which ensures a significant tapering 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 trough-like section 22, which is designed with an inclination angle of 30° to 80°.With this relatively large angle of section 22, a strong radially inward 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". The inner contour 9 ensures that a supercritical flow is maintained and that back pressures below the valve closing element 5 are limited. The thin-walled sleeve contour of the overlapping area for attachment to the nozzle body 2 initially extends 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 to stably accommodate the at least two outflow openings 17. In all illustrated embodiments, two cut-out outflow openings 17 are shown. The measures according to the invention are particularly suitable for attachment bodies 8 with two to ten outflow openings 17. According to the invention, the at least two outlet openings 17 are separated by a radially interposed insert 30. The insert 30 between the at least two outlet openings 17 acts as a jet splitter and shapes the individual gas flow paths 4 in the outlet openings 17. In the eight embodiments shown in Figs. 3, 4, 5, 6, 7, 8, 9 to 10, the inserts 30 between the outlet openings 17 have been varied in particular to produce desired jet patterns. The jet-splitting and ultimately jet-shaping insert 30 inside the attachment body 8 can be manufactured in a highly customized manner. The insert 30 is a self-contained component manufactured independently and inserted into the attachment body 8. Ideally, the insert 30 is pin-shaped and positioned along a central axis of the attachment body 8 in a central installation position. Typically, the insert 30 is coaxially symmetrical. The insert 30 is a metallic insert component, although materials such as plastic or ceramic are also conceivable. Manufacturing the insert 30 using MIM (Metal Injection Molding) or 3D printing, particularly 3D metal printing, is possible. Manufacturing the insert 30 as a turned part is also feasible. Overall, the insert 30 has an axially elongated shape resembling a contoured pin or bolt. The insert 30 is inserted into the attachment body 8, particularly from the upstream side, specifically via the trough-shaped section 2. For secure and reliable fastening of the insert 30 within the attachment body 8, the insert 30 has, for example, a circumferential annular collar 34 with a sawtooth cross-section. This collar prevents the insert 30 from slipping relative to the attachment body 8 and, via its outer contour, contributes to flow shaping in the outlet openings 17. The insert 30 forms the upstream first section of the outlet openings 17 on their radial inner surfaces with its own outer contour. If the attachment body 8 is manufactured, for example, as a plastic cap, the insert 30, made of metal or ceramic, can also be inserted into a plastic injection mold as a plunger or like a slide.Alternatively, the insert part 30 can also be firmly connected to the attachment body 8 by screwing it in, pressing it in, using an additional snap ring or by welding. It is particularly interesting to first direct the outflow openings 17 radially towards each other from the trough-like section 22 and then, via a reversing arc, to generate a radially outward flow towards the combustion chamber 20 through outflow openings 17 that diverge in the flow direction. The outflow openings 17 thus terminate in a radial outer area of ​​the end face 25 of the attachment body 8. The inner insert 30 projects, for example, upstream beyond the inlet planes of the outflow openings 17 by a certain amount. In this area, the insert 30 functions as a classic jet splitter. In cross-section, the insert 30 in this section resembles an anvil, dome, or mushroom cap. The upper surface of the insert part 30 facing the end section 6 of the valve closing element 5 can be either flat and even (Fig. 3, Fig. 4) or beveled or convex (Fig. 5, Fig. 6). In addition to jet splitting via the insert 30, this also contributes to jet shaping, as the contours of the outlet openings 17 can be designed very individually. Jet shaping can also be achieved by a specific shaping of the end section 6 of the valve closing element 5. Thus, in the embodiments according to Fig. 4 and Fig. 6, the end sections 6 of the valve closing element 5 are each shaped such that an annular bead 31 is formed on the underside facing the outlet openings 17, which allows optimized flow of the gas coming from the sealing seat 7 into the outlet openings 17. In the embodiments shown in Figs. 7, 8 to 9, the insert part 30 is shortened in the axial direction. There is no overhang as described above. Instead, the now web-like end section of the insert part 30 terminates axially either downstream of the inlet planes of the outlet openings 17 (Fig. 7) or almost exactly in the region of the inlet planes of the outlet openings 17 (Figs. 8 and 9) in the transition area from the trough-like section 22. As the figures show, embodiments of end sections 6 of the valve closing elements 5 with contours of the outlet openings 17 can be combined with one another in all conceivable variations. Fig. 9 shows an end section 6 of the valve closing element 5, which instead of an annular bead 31 has a cone-shaped flow former 32 on its underside to ensure optimized flow of the gas coming from the sealing seat 7 into the outflow openings 17.The cone-shaped flow shaper 32 can, as shown, also have a concave outer contour. A special feature is present in the embodiment shown in Fig. 7. While in all other illustrated embodiments the insert parts 30 extend to the end face 25 of the attachment body 8, here the insert part 30 is chosen as a very short insert that ends in a blind hole bore of the insert part 30, so that it is enclosed by the attachment body 8 towards the end face 25 and therefore does not itself extend to the end face 25. Figure 10 shows an embodiment as the eighth example, characterized on the one hand by an anvil-shaped insert 30 with an overhang and on the other hand by branching outflow openings 17. In this specific case, each outflow opening 17 gives off a branch opening 17a. The branch openings 17a do not necessarily open at the end 25 of the attachment body 8 facing the combustion chamber 20, but, for example, at its outer side 33. This allows for the desired jet spreading or fanning. In all described embodiments, the at least two exhaust openings 17 are arranged symmetrically or in reverse around the centrally installed insert 30. Theoretically, the insert 30 can also be positioned off-center in the attachment body 8, for example to create special one-sided jet patterns towards the combustion chamber 20. 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. 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. QUOTES INCLUDED IN THE DESCRIPTION This list of documents cited by the applicant was automatically generated and is included solely for the reader's convenience. The list is not part of the German patent or utility model application. The DPMA accepts no liability for any errors or omissions. Cited patent literature DE 10 2021 206 438 A1

[0003] WO 2023 / 001384 A1

[0004]

Claims

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), wherein 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 is located on an outer contour of the attachment body (8), in particular on an end face (25) facing the combustion chamber (20), flows into, characterized by this,that the outflow area (16) downstream of the sealing seat (7) has a trough-like section (22) to which at least two outflow openings (17) are connected downstream, wherein an insert part (30) between the at least two outflow openings (17) acts as a jet splitter and performs jet shaping of the individual gas flow paths (4) in the outflow openings (17). Injector according to claim 1, characterized in that the insert part (30) is a manufacturing-technically independent individual component that is integrated in the attachment body (8). Injector according to claim 1 or 2, characterized in that the insert part (30) has an axially elongated shape of a contoured pin or bolt. Injector according to one of the preceding claims, characterized in that the insert part (30) is inserted along a central axis of the attachment body (8) in a central installation situation. Injector according to one of the preceding claims, characterized in that the insert part (30) 30 is symmetrically designed with a coaxial course. Injector according to one of the preceding claims, characterized in that the insert part (30) is an insert component made of metal, plastic or ceramic. Injector according to one of the preceding claims, characterized in that the inner insert part (30) between the at least two outflow openings (17) facing the valve closing element (5) has a cross-sectional shape of an anvil, dome or mushroom head. Injector according to one of claims 1 to 6, characterized in that the inner insert part (30) extends in a web-like manner between the at least two outflow openings (17) towards the valve closing element (5). Injector according to one of the preceding claims, characterized in that the inner insert part (30) projects in the upstream direction beyond the inlet planes of the outflow openings (17) by a protrusion dimension. Injector according to one of claims 1 to 8, characterized in that the inner insert part (30) ends axially either downstream of the inlet planes of the outflow openings (17) or at the level of the inlet planes of the outflow openings (17) in the transition area from the trough-like section (22). Injector according to one of the preceding claims, characterized in that the upper surface of the insert part (30) facing the valve closing element (5) is either flat and even or beveled or convex. Injector according to one of the preceding claims, characterized in that the insert part (30) has a circumferential ring collar (34), in particular a ring collar (34) with a sawtooth cross-section, which ensures a secure and reliable fastening of the insert part (30) in the attachment body (8). Injector according to one of the preceding claims, characterized in that the at least two outflow openings (17) are aligned divergingly in the attachment body (8). Injector according to one of the preceding claims, characterized in that the insert part (30) can be provided as an insert in a plastic injection molding tool or that the insert part (30) can be firmly connected to the attachment body (8) by screwing in, pressing in, via an additional snap ring or via a weld connection.

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