Injector for blowing in gaseous medium

Abstract

The invention relates to an injector (1) for blowing a gaseous medium, in particular a gaseous fuel, preferably hydrogen, into a combustion chamber (20) of an internal combustion engine. Here, the injector (1) comprises in particular: an axially movable valve closing element (5) for releasing 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) arranged hydrodynamically downstream of the sealing seat (7). According to the invention, the flow-influencing geometry (10) is embodied in such a way that the following relationship is satisfied when the needle stroke (lh) of the valve closing element (5) is maximum: 5 * lhs 1.5 * lh, (s) is the distance between the radial outer contour of the valve closing element (5) at the downstream edge region thereof and an annular line on a section (12) of the flow-influencing geometry (10) which is located below in the axial projection and which contracts in the flow direction, in order to produce a substantially lossless flow downstream of the valve closing element (5).

Description

TECHNICAL FIELD

[0001] The present invention relates to an injector for blowing a gaseous medium, in particular a gaseous fuel, into a combustion chamber of an internal combustion engine. In particular, the present invention relates to an injector with which it is possible to directly blow hydrogen into a combustion chamber of an externally ignited internal combustion engine with compressed mixture. BACKGROUND

[0002] Gas injectors are known from the prior art in different configurations. In recent years, gaseous fuels are gaining in popularity for cost advantages and improved environmental compatibility. Here, the problem compared to injectors for liquid fuels is that the volume of gas to be blown in occupies a very large volume compared to the same amount of liquid fuel. This leads to an increased stroke requirement for the closing element, which is usually actuated by an electromagnetic actuator. Due to the limited installation space, a magnetic circuit design with standard materials is very difficult or partially not possible. Materials with higher magnetic force are very expensive and partially harmful to health (e.g. iron-cobalt alloys).

[0003] A gas nozzle for a gas valve is known from DE 102021206438 A1, which comprises a nozzle body which is embodied at least partially in a hollow-cylindrical manner, which constitutes a sealing seat via which a gas flow path is guided. Furthermore, the gas valve comprises a reciprocating valve closing element which is sectionally accommodated in the nozzle body, which has an end section which is arranged outside the nozzle body and which has a sealing contour which cooperates with the sealing seat. Furthermore, the gas valve has a sleeve which surrounds the nozzle body and the end section of the valve closing element, which delimits the gas flow path downstream of the sealing seat, wherein the gas flow path downstream of the sealing seat has a cross-sectional constriction in order to achieve a Venturi effect, at least one suction channel opening into the region of the cross-sectional constriction. The sleeve is embodied in the form of a spray cap which can be mounted onto the nozzle body.

[0004] A further injector for blowing in a gaseous medium is also known from WO 2023 / 001384 A1. Here, a blow cap which can be placed onto the nozzle body has a sleeve-shaped main body which has a surrounding peripheral surface which transitions into a bottom region at a downstream end. Said bottom region is embodied with at least one obliquely or asymmetrically blown out outflow opening, wherein in the bottom region a flow guiding section is also configured which points inwardly toward the valve closing element against the flow direction, which flow guiding section makes a flow deflection to the gas to be blown in. SUMMARY

[0005] In contrast thereto, the injector according to the application for blowing a gaseous medium, in particular a gaseous fuel, into a combustion chamber of an internal combustion engine according to Claim 1 has the advantage that, by means of the geometric design of the flow-influencing geometry arranged downstream of the sealing seat, an optimized gas flow in the injector can be achieved, such that the internal flow of the gaseous medium is configured as loss-free as possible by the inner contour of the cap-shaped sleeve body, so that the back pressure downstream of the valve closing element can be reduced and at the same time the jet can be introduced into the combustion chamber in a targeted manner.

[0006] Furthermore, the forces acting on the valve closing element are reduced to a minimum in a special manner. Thereby, the magnetic force of the actuator selected for keeping the injector open is reduced, and thus a low-cost material can be used in the magnetic circuit of the actuator.

[0007] According to the application, this is achieved in that the injector has a valve closing element for opening and closing at least one opening on the sealing seat. The valve closing element is preferably a valve needle which can be moved in the axial direction, which has a disc-shaped end section. Furthermore, an actuator for actuating the valve closing element is provided. The actuator is preferably an electromagnetic actuator, but can also be an actuator which operates in a mechanical or (piezo-) electric manner, for example. Further preferably, the actuator is designed to actively open the valve closing element by means of a reciprocating movement and to keep it open, whereas the valve closing element is closed by means of a spring force.

[0008] According to the application, the flow-influencing geometry, in particular installed in the cap-shaped sleeve body (in short: injector cap), is characterized in that, at a maximum needle stroke l h of the valve closing element, the following relationship applies: 5 x l h s 1.5 x l h in order to produce a virtually loss-free flow downstream of the valve closing element, wherein s is the distance between the radially outer contour of the valve closing element at its downstream edge region and the annular line lying below it in the axial projection on the constricted section of the flow-influencing geometry in the flow direction.

[0009] The dependent claims define preferred refinements of the application.

[0010] It is particularly advantageous if the constricted section of the flow-influencing geometry extends approximately conically downstream of the valve closing element. It is advantageous here if the angle of inclination a of the inner contour in the region of this constricted section is 85° a 30°, preferably greater than 45°.

[0011] In an advantageous manner, by virtue of this geometry, a strong flow deflection from a large diameter in the region of the sealing seat to a significantly smaller diameter along the constricted section of the inner contour is achieved over a short axial path length in the region of the valve closing element, so that the flow deflection is achieved in the form of an "S-shaped bend" in an advantageous manner in the region immediately downstream of the valve closing element.

[0012] The inner contour defined according to the application can be installed in an advantageous manner in a sleeve body having a reduced outer dimension, on account of its particularities in terms of shape and design. This in turn enables very flexible use of the sleeve or sleeve body on the injector in different combustion chamber geometries of internal combustion engines.

[0013] The application is preferably used in a blow-in system which blows in directly into a combustion chamber. In particular, the injector is suitable for blowing in hydrogen directly into a combustion chamber of an internal combustion engine. BRIEF DESCRIPTION OF DRAWINGS

[0014] In the following, preferred embodiments of the application are explained in detail with reference to the drawings. In the drawings, Figure 1 is a schematic sectional view of an injector for blowing in a gaseous medium according to the prior art; Figure 2 is a sectional view of a known cap-shaped sleeve body for an injector according to Figure 1 ; Figure 3 is a schematic sectional view of a cap-shaped sleeve body for an injector for blowing in a gaseous medium according to the first embodiment; Figure 4 is a schematic sectional view of a cap-shaped sleeve body for an injector for blowing in a gaseous medium according to the second embodiment; Figure 5 is a schematic sectional view of a cap-shaped sleeve body for an injector for blowing in a gaseous medium according to the third embodiment; Figure 6 is a schematic sectional view of a cap-shaped sleeve body for an injector for blowing in a gaseous medium according to the fourth embodiment; Figure 7 is a schematic sectional view of a cap-shaped sleeve body for an injector for blowing in a gaseous medium according to the fifth embodiment; Figure 8 is a schematic sectional view of a cap-shaped sleeve body for an injector for blowing in a gaseous medium according to the sixth embodiment; and Figure 9 is a schematic sectional view of a cap-shaped sleeve body for an injector for blowing in a gaseous medium according to the seventh embodiment. DETAILED DESCRIPTION

[0015] For a better understanding of the present application, in the following, the basic structure of an injector for blowing in gaseous media is described, as well as the known structure of the flow-influencing geometry arranged downstream of the valve seat in terms of fluid mechanics. Figure 1 and Figure 2 , the basic structure of an injector for blowing in gaseous media is described, as well as the known structure of the flow-influencing geometry arranged downstream of the valve seat in terms of fluid mechanics.

[0016] Figure 1 A schematic sectional view of a known injector 1 for blowing in gaseous media is shown in Fig. 1. Since the present application is directed to the flow-influencing geometry arranged downstream of the valve seat 3 in terms of fluid mechanics, only this structural assembly is described in detail here in the known injector 1. For the actuation of the injector 1, for example, an electromagnetic actuator 21 is provided, by means of which the injector 1 can be actuated in a targeted manner.

[0017] The injector 1 also has a nozzle body 2 which, on the blowing side, constitutes a valve seat 3 in the form of a conical shaping at the end, for a valve closing element 5 which opens outwards, i.e. in the direction of the combustion chamber 20. The valve closing element 5 is axially movably guided in the nozzle body 2 by means of a guide 18. Furthermore, the valve closing element 5 has an end section 6 in the form of a valve disc which forms a sealing seat 7 in cooperation with the valve seat 3. The two sealing seat partners, valve seat 3 and valve closing element 5, are embodied here as metal. The design in terms of geometry and material technology is carried out here in such a way that sufficient sealing is ensured during operation of the hydrogen engine. In the event of a fault, a shut-off system (not shown here) connected upstream of the injector 1 in terms of fluid mechanics is responsible for interrupting the supply of gaseous media, in particular of the volatile hydrogen, for safety reasons. The sealing contour of the end section 6 of the valve closing element 5 is embodied, for example, as rounded, while the valve seat 3 on the nozzle body 2 has a taper. However, other contours are also conceivable.

[0018] The nozzle body 2 and the end section 6 of the valve closing element 5 are surrounded by a sleeve 8 for beam shaping. In the following, the flow-influencing geometry 10 arranged downstream of the sealing seat 7 in terms of fluid mechanics is generally discussed, in particular also with regard to the present application. This flow-influencing geometry can be embodied on the one hand directly integrally on the nozzle body 2, but this requires high manufacturing outlay, or can be integrated in an additional component, wherein this component is generally referred to as sleeve 8 in terms of the prior art according to Figure 1 and Figure 2 . The sleeve 8 has a large overlap length with the nozzle body 2 in order to be able to fix the sleeve 8 safely and reliably. However, in principle, a hat-shaped sleeve 8 can also be discussed, which is also defined as a blow-off cap 8 in terms of embodiments of the present application.

[0019] The sleeve 8 and the end section 6 of the valve closing element 5 jointly delimit a gas flow path 4, into which at least one suction channel 15 configured in the sleeve 8 opens. Air from the surroundings can be sucked into the gas flow path 4 via the one or more suction channels 15.

[0020] If the valve closing element 5 is in an open position lifted from the valve seat 3, the gas flow path 4 extends via the valve seat 3 into an interior space of the sleeve 8, which is characterized by a special shape of the inner contour 9. Following the valve closing element 5 in the flow direction from the cylindrical section 11 of the sleeve 8, a cross-sectional reduction takes place in a flow-influencing geometry 10 of the sleeve 8 with a large axial distance from the valve closing element 5 in a cylindrical intermediate axial region 13 of the sleeve 8, wherein the constriction is effected by a tapering extending section 12 in the inner contour 9 of the sleeve 8. The suction channel 15 opens into the inner contour 9 of the sleeve 8 just in the intermediate axial region 13.

[0021] The cross-sectional reduction within the gas flow path 4 is responsible for the following effect: When gas flows out in the direction of the outlet 19 via the gas flow path 4, air from the surroundings is sucked into the gas flow path 4 via the suction channel 15 (Venturi effect). This means that the gas is also mixed with air before it reaches the outlet 19, thus improving the production of the mixture in this way.

[0022] The cross-sectional reduction is in turn cancelled by the fact that a tapering extending section 14 follows the intermediate axial region 13, however in this case the section widens conically in the flow direction, wherein the section 14 extends up to the outlet 19. The cross-sectional reduction in the inner contour 9 of the sleeve 8 is thus provided for realizing the Venturi effect, which is optimized together with the air mixture.

[0023] According to the invention, with such a solution or with other known geometries or inner contours of the cap-shaped sleeve, insufficiently good results cannot be achieved for optimizing the combustion in terms of the introduction of the jet into the combustion chamber 20 or in terms of the jet guidance and jet shaping.

[0024] The task of the present invention is therefore to provide an inner contour 9 of a cap-shaped sleeve 8, which has a flow-influencing geometry 10 arranged downstream of the sealing seat 7 in terms of fluid mechanics, with which an optimized combustion result is achieved on the basis of the flow guidance according to the invention.

[0025] The task of the injection system for direct injection of gaseous media, in particular hydrogen, but also compressed natural gas, methane, ammonia or mixtures of the aforementioned gases, is to control the metering and the injection direction of the gas jet into the combustion chamber 20 through the injection valve or generally through the injector 1 with pinpoint accuracy. For this purpose, as already mentioned, a corresponding sleeve or injection cap 8 can be used on the injector 1. In addition, the injection system for (hydrogen) direct injection has a large stroke requirement on the valve needle with the valve closing element 5 depending on the principle. Due to the limited installation space, it is very difficult and even partially impossible to design the magnetic circuit of the known standard material design (electromagnetic actuator 21). Materials with a higher magnetic force and thus better B / H characteristics are very expensive and partially harmful to health (e.g. iron-cobalt alloys). In this regard, a reduction in the magnetic force should also be achieved by an improved jet guidance.

[0026] The core of the invention is that by means of the inner contour 9 of the cap-shaped sleeve 8 according to the invention, the internal flow of the gaseous medium is configured as loss-free as possible, thereby reducing the back pressure downstream, i.e. below the disc-shaped end section 6 of the valve closing element 5, and at the same time the jet can be introduced into the combustion chamber 20 with pinpoint accuracy. This defined inner contour 9 can be advantageously designed in its uniqueness in shape and design in the sleeve 8 with reduced outer dimensions. This in turn enables the sleeve or sleeve 8 to be used very flexibly on the injector 1 in different combustion chamber geometries of internal combustion engines.

[0027] In the following, the injector 1 according to the preferred embodiment of the invention is described in detail with reference to Figures 3 to 9 , which has a flow-influencing geometry 10 according to the invention arranged downstream of the valve seat 3 in terms of fluid mechanics. As already mentioned, this flow-influencing geometry 10 can be formed together directly integrally on the nozzle body 2, but can also be integrated as shown in all the figures in an additional component which can be referred to as a cap-shaped sleeve 8 (short: injection cap 8). Here, the overlap length of the sleeve 8 with the nozzle body 2 is generally significantly shorter than shown in Figure 1 . Important is in particular the secure and reliable fixing of the sleeve 8 on the nozzle body 2, which enables a perfect and axis-parallel orientation of the injector 1. Known joining methods such as press fitting, fusion welding, brazing, adhesive bonding or combinations thereof can be used.

[0028] A first embodiment of the flow-influencing geometry 10, which is arranged downstream of the valve seat 3 in terms of fluid mechanics in the cap-shaped sleeve 8 and is generated by the inner contour 9 according to the invention, is shown in Figure 3 . Here, the valve closing element 5 and its disc-shaped end section 6 are only shown schematically and simplified. However, the end section 6 can also have a chamfer or a rounding on its outer contour.

[0029] The flow-influencing geometry 10 produced with the inner contour 9 according to the application has a number of important aspects and geometric specifications, wherein the ratio of two areas to one another is an important criterion of the application, specifically, for this, the two areas A s and Al are examined, which are obtained with the maximum needle stroke 1 h , i.e. with the maximum opening of the sealing seat 7 and thus with the maximum lifting of the valve closing element 5. Here, the area A s is the annular seat cross-sectional area obtained between the contact line of the valve seat 3 and the end section 6 of the valve closing element 5; while the area Al is determined by the distance obtained as the shortest path between the oppositely disposed walls of the outer contour and the inner contour 9 on the edge region of the valve closing element 5 downstream thereof. In other words, the area Al reflects the narrowest cross section under the valve closing element 5 with the maximum opening of the sealing seat 7. This area Al also extends annularly and as an imaginary area here approximately at right angles to the constricted, in particular conically extending section 12 in the inner contour 9 of the sleeve 8; this section is responsible for the pronounced constriction of the inner contour 9 over a short axial extension, which in an advantageous manner also contributes to achieving the desired optimized flow result. According to the application, the ratio of the areas A s and Al should satisfy: Al 2.5 x A s .

[0030] The jet from the sealing seat 7 is guided here via the inner contour 9 in the conically extending section 12, which is embodied with a 60° α 30° inclination angle a, preferably greater than 45°. With this comparatively large inclination angle a of the conically extending section 12, a strong flow component directed radially inwards is produced over a very short axial extension length. The lines of the flow path 4 make this clear.

[0031] A further characteristic variable of the configuration of the inner contour 9 is the distance s, which is obtained between the radial outer contour on the edge region of the valve closing element 5 downstream thereof and the annular line on the conically extending section 12 lying thereunder in axial projection with the maximum needle stroke 1 h . Here, it should satisfy: 5 x 1 h s 1.5 x 1 h , in order to produce a virtually loss-free flow around the end section 6 of the valve closing element 5. In particular, for an optimized flow result, 4 x 1 h s 2.5 x 1 h is satisfied. The maximum needle stroke 1 hextends over an axial extension of 100 μm to 2 mm, wherein the maximum needle stroke l h Ideally it will be between 0.15 mm and 0.5 mm.

[0032] Thus, by these geometrical provisions, over a short axial path length in the region of the valve closing element 5, a flow turnaround from a large diameter in the region of the sealing seat 7 to a significantly smaller diameter with the internal area A2 at the end of the constricted, in particular conically extending section 12 is achieved, so that in this region, immediately downstream of the valve closing element 5, the flow deflection is advantageously achieved in the form of an "S-shaped turn". Instead of a conical course of this section 12, it can also be slightly convexly arched or slightly concavely arched. Thus, in addition to the proportion of the flow cross section corresponding to A1 2.5 x A s , the flow cross sections for the areas A s and A2 should additionally also satisfy the following: 5 x A s A2 2 x A s , so as to ensure supercritical flow and to achieve a limitation of the back pressure below the valve closing element 5.

[0033] Furthermore, the flow acceleration into the actual outlet opening, which is characterized by an axial region 13 following the conically extending section 12 in the flow direction, is relevant in the case of a reduction of the losses or eddy currents in the wall region and an effective flow cross section close to the geometrical cross section area A2. These measures allow a reduction of the outlet area of the inner bore given by the inner contour 9 in the region of the outlet 19 without influencing the back pressure below the valve closing element 5. In the present embodiment according to Figure 3 , the diameter d2 of the internal flow path at the inlet into the axial region 13 and the diameter d3 of the outlet at the exit from the axial region 13 in the region of the outlet 19 are chosen to be approximately the same size, so that there is an approximately cylindrical outlet opening with the axial region 13.

[0034] A reduction of the diameter d3 in the region of the axial region 13 of the outlet opening in the direction of the outlet 19 increases the hole length L, i.e. the proportion of the axial length of the axial region 13 to the outlet diameter d3, which improves the beam stability and, above all, the beam speed. With regard to the aforementioned parameters, the following relationships should be satisfied: L / d2 0.2; L / d3 0.2; but ideally L / d3 > 1.

[0035] In the case of a conical course of the section 12, the diameter d2 of the inlet into the axial region 13 and the diameter d3 of the outlet at the exit from the axial region 13 in the region of the outlet 19 are chosen to be approximately the same size, so that there is an approximately cylindrical outlet opening with the axial region 13. Figures 4 to 9Six further embodiments of the flow-influencing geometry 10 are shown, which, in terms of fluid dynamics, is arranged downstream of the valve seat 3 in the cap-shaped sleeve 8 and is generated by the inner contour 9 according to the invention. Here, modifications in the regions of sections 12 and 13 of the cap-shaped sleeve 8 are presented first, which achieve the aforementioned advantageous effects.

[0036] exist Figure 4 One solution is shown where a hole taper exists in the axial region 13 of the inner contour 9. Here, the angle k of the hole taper is 20°. k 2°. Therefore, corresponding to the hole length L, the diameter d3 can be reduced by 5% to 50% compared to the diameter d2.

[0037] exist Figure 5 The image shows a hat-shaped suit body 8, in which a very large tilt angle α is selected in the tapered extension section 12, wherein this angle α can be, for example, up to 85°. Here, it should also be satisfied again: 5×l h s 1.5×l h This allows for virtually lossless flow around the end section 6 of the valve closing element 5. This relationship can be achieved through the large angle α of the tapered extension section 12, moving towards 3×l. h s 1.5×l h The axial region 13 of the inner contour 9 can extend in a cylindrical or conical shape.

[0038] Figure 6 and Figure 7 Two embodiments are shown, in which the outlet orifice is further divided within the axial region 13. According to... Figure 6 In this embodiment, the initially cylindrical axial region 13 abruptly transitions to an end region 13a with a spherical arch. This spherical arch extends convexly when viewed from the inside and is responsible for anchoring the flow, which may be desirable for given installation conditions and combustion chamber structure. The radius R of the spherical arch in the end region 13a is not necessarily constant.

[0039] According to Figure 7 In this embodiment, the initially tapered axial region 13 transitions into an end region 13b upon bending. This end region also extends taperedly, but here has an angle k smaller than that of the axial region 13. As shown, the tapered axial region 13 can also transition into a cylindrical end region 13b. For the areas A2 and A3 in the regions with diameters d2 and d3, the following condition should be met: 0.8 × A2 A3 0.5×A2.

[0040] According to Figure 8 In one embodiment, a division of the outlet hole is also provided in the axial region 13. According to... Figure 8 In this embodiment, the initially cylindrical axial region 13 transitions with a bend into a tapered, tapering end region 13c that tapers along the flow direction. The relationship between areas A2 and A3 can also be correspondingly described for... Figure 6 and Figure 7 As explained, it applies.

[0041] exist Figure 9 The diagram shows a cap-shaped assembly 8 containing a modified valve closing element 5, the end section 6 of which has an additional flow-forming portion 22. This flow-forming portion, unlike the actual disc-shaped configuration, has a downstream-facing profile. The flow-forming portion 22 can be, for example, a needle tip formed in a conical or cylindrical shape on the valve closing element 5. For a cylindrical or tapered flow-forming portion 22, the following proportional relationship should be satisfied with respect to the diameter d2 at the inlet in the axial region 13: 2 / 3 × d2 b 1 / 3×d² (cylindrical); 2 / 3×d² b1; b2 1 / 3 × d² (conical). The illustrated embodiment shows a flow-forming section 22, the diameter of which b1 begins at the end section 6 of the valve closing element 5 and corresponds to the diameter of the valve needle rod upstream of the end section 6. However, this is only one possible configuration variation. However, the diameter b1 can also be larger or smaller than the diameter of the valve needle rod. The flow-forming section 22 can also extend downstream, for example, from the radial outer contour of the end section 6 of the valve closing element 5.

[0042] Generally, the flow shaping section 22 can be described as providing an additional, downstream-direction axial component assembly on the downstream bottom side of the end section 6 of the valve closing element 5, which is different from the generally disc-shaped configuration, and the component assembly is thus part of the geometry 10 that affects the flow.

[0043] according to Figures 3 to 8 The configurational variation of the embodiment with respect to the inner contour 9 of the outlet hole with axial region 13 can be readily adapted to the embodiment. Figure 9 The configuration of the valve closing element 5 with the flow forming part 22 is combined. When the sealing seat 7 is fully open, and thus at the maximum valve needle stroke l... h In this case, the axial length of the flow forming section 22 should be less than the distance between the valve disc and the inlet in the axial region 13.

[0044] The flow shaping 22 at the bottom side downstream of the valve closing element 5 enables flow stabilization of the internal flow immediately downstream of the valve disc and reduces the forces acting there. By the respective dimensions of the flow shaping 22 shown above, the influence on the valve needle in terms of stiffness is limited.

[0045] Furthermore, a more flexible configuration of the hole design is achieved with the proposed solution, which can be required, for example, in the case of limited installation space. Thus, an increased degree of freedom is provided for different dimensions of the cap-shaped sleeve 8, wherein the outer diameter of the sleeve 8 in the region fixed on the nozzle body 2 is, for example, in the range of 8 mm to 15 mm, while the outer diameter of the sleeve 8 in the region of the outlet 19 is, for example, in the range of 6 mm to 12 mm. In general, these configurations can be supplemented or combined in different sub-variant solutions with transitions with corners and with sharp edges by means of radii R in the form of rounding (see, for example, Fig. 6). Figure 5 ​

Claims

1. An injector (1) for injecting a gaseous medium, particularly a gaseous fuel, preferably hydrogen, into the combustion chamber (20) of an internal combustion engine, said injector comprising: A valve closing element (5) capable of axial movement is used to release and close at least one opening at the sealing seat (7); Actuator (21) for manipulating the valve closing element (5); and a flow-influencing geometry (10) arranged downstream of the sealing seat (7) in a hydrodynamic manner, characterized in that, during the needle stroke (l) of the valve closing element (5) h In the maximum case, the following ratio is satisfied: 5×l h s 1.5×l h , where (s) is the distance between the radial outer contour of the valve closing element (5) at its downstream edge region and the annular line located below it in the axial projection on the flow-direction contracting section (12) of the flow-influencing geometry (10) to produce almost lossless flow downstream of the valve closing element (5).

2. The injector according to claim 1, characterized in that, The preferred ratio is 4×l h s 2.5×l h .

3. The injector according to claim 1 or 2, characterized in that, At the maximum valve needle stroke (l h In the case of ), an annular seat cross-sectional area (A) is obtained between the contact line of the valve seat (3) and the valve closing element (5). s ), and the additional annular area (A1) is determined by the following distance: this distance is obtained as the shortest path between the outer contour of the valve closing element (5) at its downstream end and the opposite wall of the flow-influencing geometry (10) in the section (12) that contracts in the flow direction, wherein, for the area (A1) s In terms of the ratio of A1 to A1, the following condition is met: 2.5×A s .

4. The injector according to claim 3, characterized in that, At the end of the section (12) that contracts along the flow direction, there follows an outlet orifice with at least one axial region (13), thus defining the entire inner contour (9) of the flow-influencing geometry (10) up to the outlet (19), wherein an internal area (A2) is defined at the beginning of the axial region (13), and with respect to the cross-sectional area of ​​the annular seat (A2). s For example, 5×A satisfies the following: s A2 2×A s .

5. The injector according to claim 4, characterized in that, The outlet hole has an axial region (13) that is divided into multiple sub-segments.

6. The injector according to claim 4 or 5, characterized in that, The axial region (13) following the section (12) that contracts along the flow direction of the outlet hole extends either cylindrically or in a similarly contracting manner.

7. The injector according to any one of claims 4 to 6, characterized in that, The outlet orifice has downstream end regions (13a, 13b, 13c) leading to the outlet (19), which are constructed either cylindrically, conically contracted, or spherically arched and contracted.

8. The injector according to any one of claims 4 to 7, characterized in that, The diameter (d3) of the axial region (13) of the outlet hole in the region of the outlet (19) is less than or equal to the diameter (d2) at the beginning of the axial region (13).

9. The injector according to any one of the preceding claims, characterized in that, The flow-influencing geometry (10) extends in a generally tapered shape in the section (12) downstream of the valve closing element (5) that contracts in the flow direction.

10. The injector according to any one of the preceding claims, characterized in that, The flow-influencing geometry (10) is implemented in the section (12) downstream of the valve closing element (5) that contracts along the flow direction, with an angle of 85°. α An inclination angle α of 30° is preferred, and an inclination angle α of more than 45° is preferred.

11. The injector according to any one of the preceding claims, characterized in that, The flow-influencing geometry (10) arranged downstream of the sealing seat (7) in terms of fluid dynamics is realized in the cap-shaped suit (8), especially in the blow cap.

12. The injector according to claim 11, characterized in that, The cap-shaped sleeve (8) can be installed on the ejection side end of the injector (1), especially on the nozzle body (2).

13. The injector according to any one of the preceding claims, characterized in that, The valve closing element (5) is part of a valve needle capable of axial movement, wherein the valve closing element (5) has an end section (6) which is generally disc-shaped.

14. The injector according to claim 13, characterized in that, A flow forming part (22) is provided on the downstream bottom side of the end section (6) of the valve closing element (5), which provides an additional axial component assembly in the downstream direction for a generally disc-shaped configuration, and the component assembly is thus part of the flow-influencing geometry (10).

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