Injector that sprays 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) in this case, in particular, has an axially movable valve closing member (5) for opening and closing at least one opening in a seal seat (7), an actuator (21) for operating the valve closing member (5), and a flow-influencing geometry (10) located downstream of the seal seat (7) in a flow-technically manner. According to the present invention, the flow-influencing geometry (10) is the needle stroke (I h When ) is at its maximum, the following relationship holds: 5 × I h ≥s ≥ 1.5 × I h The following holds true, in which case (s) is the distance between the radially outer contour of the valve closing member (5) in the downstream edge region of the valve closing member and the annular line at the tapered portion (12) in the flow direction of the flow-influencing geometry (10) located below it in the projection view in the axial direction, thereby generating a flow with virtually no loss downstream of the valve closing member (5).

Description

[Technical Field]

[0001] Background technology The present invention relates to an injector for injecting a gaseous medium, particularly a gaseous fuel, into the combustion chamber of an internal combustion engine. In particular, the present invention relates to an injector capable of directly injecting hydrogen into the combustion chamber of a fuel-air-compression type spark-ignition internal combustion engine.

[0002] Gas injectors are known in various configurations through prior art. Due to cost advantages and improved environmental compatibility, gaseous fuels have been continuously preferred in recent years. In this case, the problem compared to liquid fuel injectors is that the amount of gas to be injected occupies a significantly larger volume compared to the equivalent amount of liquid fuel. As a result, the required stroke of the closing member, usually operated by a magnetic actuator, becomes higher. Designing magnetic circuits using standard materials is extremely difficult, or even partially impossible, due to limited structural space. Materials with higher magnetic force are extremely expensive and, in part, harmful to health (e.g., FeCo).

[0003] A gas nozzle for a gas valve, already known from German Patent Application Publication No. 102021206438, has a nozzle body formed at least partially in a hollow cylindrical shape, the nozzle body forming a seal seat, and a gas passage passing beyond the seal seat. Furthermore, the gas valve has a stroke-movable valve closing member partially housed within the nozzle body, the valve closing member having an end section located outside the nozzle body, the end section having a seal contour cooperating with the seal seat. Furthermore, the gas valve has a sleeve surrounding the nozzle body and the end section of the valve closing member, the sleeve defining a gas passage downstream of the seal seat, in which case the gas passage has a cross-sectional reduction downstream of the seal seat to obtain a Venturi effect, and at least one suction passage is open in the region of this cross-sectional reduction. The sleeve is configured in the form of a blow cap that can be mounted on the nozzle body.

[0004] Another injector for ejecting a gaseous medium is also known from International Publication No. 2023 / 001384. A blow cap mountable on a nozzle body has, in this case, a sleeve-shaped base with an annular circumferential surface, the annular circumferential surface transitioning to a bottom region at the downstream end. The bottom region is configured to have at least one outlet opening that blows out obliquely or asymmetrically, and in this case the bottom region is further formed with a flow guide section directed inward toward a valve closing member in the opposite direction to the flow direction, the flow guide section deflects the flow of the gas to be ejected.

[0005] Disclosure of the invention In contrast, the injector according to the present invention, having the features of claim 1, for injecting a gaseous medium, particularly a gaseous fuel, into the combustion chamber of an internal combustion engine, enables optimal gas flow within the injector through the geometric design of flow-influencing geometry located downstream of the seal seat, thereby forming the internal flow of the gaseous medium through the inner contour of the cap-shaped mounting body with as little loss as possible, thereby reducing the dynamic pressure located below, i.e., downstream of, the valve closing member, and simultaneously having the advantage of introducing the jet into the combustion chamber as intended.

[0006] Furthermore, the force acting on the valve closing member is reduced to a minimum in a special manner. This reduces the magnetic force of the actuator that must be selected to hold the injector open, and therefore allows for the use of low-cost materials in the actuator's magnetic circuit.

[0007] This is achieved according to the present invention by the injector having a valve closing member for opening and closing at least one opening in the seal seat. The valve closing member is preferably an axially movable valve needle having a disc-shaped end section. Furthermore, an actuator is provided for operating the valve closing member. The actuator is preferably a magnetic actuator, but may be, for example, a mechanically or (piezo)electrically operated actuator. More preferably, the actuator is configured to actively open and hold the valve closing member in the open state by stroke motion, and on the other hand, to close the valve closing member by spring force.

[0008] In particular, the geometry that affects the flow, provided on the cap-shaped mounting body, or blow cap for short, according to the present invention, is the needle stroke I of the valve closing member. h When is at its maximum, the following relationship holds: 5 × I h ≥s ≥ 1.5 × I h The following holds true, in which case s is the distance between the radially outer contour of the valve closing member in the downstream edge region of the valve closing member and the annular line in the flow direction tapering portion of the flow-influencing geometry located below it in the axial projection view, which is superior in that it generates a virtually lossless flow downstream of the valve closing member.

[0009] The dependent claims describe other preferred configurations of the present invention.

[0010] Particularly advantageous is that the tapered portion in the flow direction of the flow-influencing geometry extends in a substantially conical shape downstream of the valve closing member. In this case, advantageously, the inclination angle α of the inner contour in the tapered region is 85° ≥ α ≥ 30°, and preferably greater than 45°.

[0011] Advantageously, this geometric setting allows for strong flow back along the inner contour in the valve closing member region, over short axial lengths, from a large diameter in the seal seat region to an extremely small diameter in the tapered section. As a result, in this region, flow deflection immediately downstream of the valve closing member occurs, advantageously in the form of an "S-shaped twist."

[0012] The internal contour defined by this invention, due to its shape and design characteristics, can be provided in an advantageous form on a mount having a reducible external dimension. This further enables extremely flexible use of the sleeve or mount in the injector in various combustion chamber geometries of internal combustion engines.

[0013] The present invention is preferably used in an injection system that injects directly into the combustion chamber. In particular, this injector is suitable for directly injecting hydrogen into the combustion chamber of an internal combustion engine.

[0014] Preferred embodiments of the present invention will be described in detail below with reference to the accompanying drawings. [Brief explanation of the drawing]

[0015] [Figure 1] This is a schematic cross-sectional view showing a conventional injector that sprays a gaseous medium. [Figure 2] Figure 1 is a cross-sectional view showing a known cap-shaped mounting body for an injector. [Figure 3] This is a schematic cross-sectional view showing a cap-shaped mounting body for an injector that sprays a gaseous medium, according to the first embodiment. [Figure 4] This is a schematic cross-sectional view showing a cap-shaped mounting body for an injector that sprays a gaseous medium, according to a second embodiment. [Figure 5] This is a schematic cross-sectional view showing a cap-shaped mounting body for an injector that sprays a gaseous medium, according to a third embodiment. [Figure 6]Schematic cross-sectional view of a cap-shaped carrier for an injector for injecting a gaseous medium according to a fourth embodiment. [Figure 7] Schematic cross-sectional view of a cap-shaped carrier for an injector for injecting a gaseous medium according to a fifth embodiment. [Figure 8] Schematic cross-sectional view of a cap-shaped carrier for an injector for injecting a gaseous medium according to a sixth embodiment. [Figure 9] Schematic cross-sectional view of a cap-shaped carrier for an injector for injecting a gaseous medium according to a seventh embodiment.

[0016] Preferred embodiments of the invention For a better understanding of the present invention, the basic structure of an injector for injecting a gaseous medium and the known structure of a geometry affecting the flow, which is arranged downstream of the valve seat in terms of flow technology, will be described below with reference to FIGS. 1 and 2.

[0017] In FIG. 1, a known injector 1 for injecting a gaseous medium is shown in a schematic cross-sectional view. Since the present invention is directed to a geometry 10 affecting the flow, which is arranged downstream of the valve seat 3 in terms of flow technology, only this group of components will be described in detail here for the known injector 1 as well. To operate the injector 1, for example, a magnetic actuator 21 is provided, by means of which the injector 1 can be accurately controlled via this.

[0018] Furthermore, the injector 1 has a nozzle body 2, which at the end of the nozzle body on the injection side forms a valve seat 3, for example, shaped like a cone, for a valve closing member 5 that opens outward, i.e., toward the combustion chamber 20. The valve closing member 5 is guided axially movable within the nozzle body 2 via a guide 18. Furthermore, the valve closing member 5 has an end section 6 in the form of a valve disc, which forms a seal seat 7 corresponding to the valve seat 3. Both sealing surface partners, the valve seat 3 and the valve closing member 5, are formed from metal in this case. In this case, the geometric and material-technical design is carried out so as to ensure sufficient sealing during the operation of the hydrogen engine. In the event of a failure, for safety reasons, a shut-off system, not shown here, connected to the flow-technically upstream side of the injector 1, works to cut off the supply of gaseous medium, particularly easily volatile hydrogen. The seal contour of the end section 6 of the valve closing member 5 is formed, for example, rounded, whereas the valve seat 3 in the nozzle body 2 has a cone. However, other contours are also possible.

[0019] The nozzle body 2 and the end section 6 of the valve closing member 5 are surrounded by a sleeve 8 for jet formation. Hereinafter, particularly in relation to the present invention, a flow-influencing geometry 10, generally located downstream of the seal seat 7 in flow technology, will be described. This flow-influencing geometry may, on the one hand, be directly molded integrally with the nozzle body 2, but this would require significant manufacturing effort. Alternatively, the flow-influencing geometry may be incorporated into an additional component, in which case such a component is generally referred to as the sleeve 8 in relation to the prior art configurations shown in Figures 1 and 2. The sleeve 8 has a large overlap length with the nozzle body 2 to allow for secure and reliable mounting. However, it may also be referred to as a cap-shaped mounting body 8, which, in relation to embodiments of the present invention, is also defined as a blow cap 8.

[0020] The sleeve 8 and the end section 6 of the valve closing member 5 together define a gas flow path 4, into which at least one suction passage 15 formed within the sleeve 8 opens. Air can be drawn into the gas flow path 4 from the surroundings through one or more suction passages 15.

[0021] If the valve closing member 5 is in an open position, lifted from the valve seat 3, then the gas passage 4 extends beyond the valve seat 3 into the chamber of the sleeve 8, which is distinguished by the special shaping provided by the inner contour 9. Starting from the cylindrical section 11 of the sleeve 8, and following the valve closing member 5 in the flow direction, the passage reaches a reduction in cross-section in the intermediate cylindrical axial region 13 of the geometry 10 that affects the flow of the sleeve 8, at a large axial distance from the valve closing member 5. In this case, the reduction in diameter is reached via a conical extension 12 in the inner contour 9 of the sleeve. The suction passage 15 opens into the inner contour 9 of the sleeve 8, precisely in the intermediate axial region 13.

[0022] The reduced cross-sectional area on the inside of the gas flow path 4 creates an effect ("Venturi effect") in which air is drawn into the gas flow path 4 from the surroundings via the intake passage 15 as the gas flows out towards the outlet 19 through the gas flow path 4. In other words, air is mixed with the gas before it reaches the outlet 19, thereby improving the adjustment of the mixture.

[0023] The cross-sectional reduction is again eliminated by a conical extension 14 that continues in the intermediate axial region 13, although in this case it expands conically in the flow direction, and this section 14 extends to the outlet 19. Thus, the cross-sectional reduction in the inner contour 9 of the sleeve 8 is provided to obtain a Venturi effect that is optimized with air mixing. Empirically, such solutions, or other known geometries or inner contours of cap-shaped mounts, do not yield sufficiently good results with respect to the introduction of the jet into the combustion chamber 20 for optimal combustion or to jet guiding and jet shaping in the combustion chamber.

[0024] Therefore, the object of the present invention is to provide an inner contour 9 of a cap-shaped mounting body 8 having a flow-influencing geometry 10 that is positioned downstream of the seal seat 7 in a flow-technically manner, and that yields optimal combustion results based on the flow guide according to the present invention.

[0025] Injection systems for directly injecting gaseous media, particularly hydrogen, as well as CNG, methane, ammonia, or mixtures thereof, face the challenge of controlling both the metering of the gas jet and the injection direction into the combustion chamber 20 as desired, via an injection valve or generally an injector 1. For this purpose, a suitable sleeve or injection cap 8 can be used in the injector 1, as already described above. Furthermore, due to the principle, injection systems for direct (hydrogen) injection require a large stroke for the valve needle equipped with a valve closing member 5. Designing magnetic circuits (magnetic actuators 21) using known standard materials is extremely difficult or partially impossible due to limited structural space. Materials with higher magnetic force and thus better B / H characteristics are extremely expensive and partially harmful to health (e.g., FeCo). Therefore, it is desirable that magnetic force reduction be achieved with respect to the improved jet guide as well.

[0026] The core of the present invention lies in forming an internal flow of a gaseous medium with as little loss as possible through the internal contour 9 of the cap-shaped mounting body 8 according to the present invention, thereby reducing the dynamic pressure located below, i.e., downstream of, the disc-shaped end section 6 of the valve closing member 5, while simultaneously allowing the jet to be introduced into the combustion chamber 20 as intended. Due to its shape and design, this defined internal contour 9 can be provided in an advantageous form on a mounting body 8 having a reducible external dimension. This further enables extremely flexible use of the sleeve or mounting body 8 in the injector 1 in various combustion chamber geometries of internal combustion engines.

[0027] Below, with reference to Figures 3 to 9, an injector 1 having flow-influencing geometry 10 according to the present invention, which is flow-technically positioned downstream of the valve seat 3, will be described in detail according to a preferred embodiment of the present invention. As already mentioned above, this flow-influencing geometry 10 may be directly and integrally molded together with the nozzle body 2, or it may be incorporated into an additional component that can be called a cap-shaped mount 8 (abbreviated as blow cap 8), as shown in the full figures. In this case, the mount 8 may have an overlap length with the nozzle body 2 that is usually significantly reduced than that shown in Figure 1. The important thing is a secure and reliable attachment to the nozzle body 2 that allows for perfect and axially parallel orientation with respect to the injector 1. Known joining methods such as press fitting, welding, brazing, bonding, or a combination thereof can be used.

[0028] Figure 3 shows a first embodiment of the flow-influencing geometry 10 generated via the inner contour 9 according to the present invention, which is flow-technically positioned downstream of the valve seat 3 in the cap-shaped mounting body 8. In this case, the valve closing member 5 is only schematically and simply illustrated with its disc-shaped end section 6. However, the end section 6 may have chamfered or rounded portions on its outer contour.

[0029] The flow-influencing geometry 10 generated by the inner contour 9 according to the present invention has several important aspects and geometrical definitions, in which case the ratio of two surfaces to each other is an important criterion for the present invention. That is, for this purpose, the maximum valve needle stroke l h Under these conditions, that is, under the fully open seal seat 7, and consequently under the fully raised valve closing member 5, two areas A are generated. s And A1 is taken into consideration. In this case, area A sis the annular seat cross-sectional area that occurs between the valve seat 3 and the contact line of the end section 6 of the valve closing member 5, whereas the area A1 is defined by the interval that occurs as the shortest distance between the outer contour of the valve closing member 5 in the edge region on the downstream side of the valve closing member and the confronting wall of the inner contour 9. In other words, the area A1 forms the narrowest cross-section on the lower side of the valve closing member 5 when the seal seat 7 is fully opened. This area A1 also extends in an annular shape and, as a virtual area, extends here approximately at a right angle to the tapered, particularly conical extension 12 in the inner contour 9 of the carrier 8. This conical extension serves to significantly narrow the inner contour 9 in a short axial extension, which also suitably contributes to the optimized desired flow result. According to the invention, the ratio of the area A s to A1 is preferably such that A1 ≧ 2.5 × A s holds.

[0030] In this case, the jet guide coming from the seal seat 7 is effected via the inner contour 9 in the conical extension 12 that is configured with an inclination angle α of 60° ≧ α ≧ 30°, preferably an inclination angle α greater than 45°. This very large angle α of the conical extension 12 gives rise to a strong flow component directed radially inward in a very short axial extension length. The lines of the flow path 4 clearly show this.

[0031] Another characteristic value of the configuration of the inner contour 9 is the interval s that occurs between the radially outer contour of the valve closing member 5 in the edge region on the downstream side of the valve closing member and the annular line in the conical extension 12 that is located below it in the axial direction as seen in the projection view when the needle stroke l h is at its maximum. In this case, 5 × I h ≧ s ≧ 1.5 × I h is preferably satisfied. Thereby, a flow with substantially no loss can be generated around the end section 6 of the valve closing member 5. In particular, for an optimal flow result, 4 × I h ≧ s ≧ 2.5 × I h holds. The maximum needle stroke I hIn this case, it extends over an axial length of 100 μm to 2 mm, and in this case, the maximum needle stroke I h Ideally, this should be between 0.15mm and 0.5mm.

[0032] In other words, with this geometric setting, in the region of the valve closing member 5, over a short axial section length, flow is redirected from a large diameter in the region of the seal seat 7 to a tapered, particularly small diameter with an internal area A2 at the end of the conical extension 12. This results in flow deflection in this region, immediately downstream of the valve closing member 5, preferably in an "S-shaped twist" configuration. Instead of a conical extension of section 12, this section 12 may extend in a slightly convex or slightly concave curve. Thus, A1 ≥ 2.5 × A s In addition to the ratio of the flow cross-sections corresponding to the area A, further supplementary information is provided. s And the flow cross section of A2 is as follows, namely, 5 × A s ≥A² ≥ 2 × A s It is desirable that this condition be met, which guarantees supercritical flow and achieves limitation of the dynamic pressure below the valve closing member 5.

[0033] Consequently, while further reducing losses or vortices in the wall region and approximating the effective flow cross-section to the geometric cross-sectional area A2, an acceleration of the flow into the original outlet hole, characterized by the axial region 13 that continues in the flow direction to the conical extension 12, occurs. By taking such measures, the outflow area of ​​the inner hole defined by the inner contour 9 in the outlet 19 region can be reduced without affecting the dynamic pressure below the valve closing member 5. In this embodiment shown in Figure 3, the diameter d2 of the inner flow path in the inflow portion into the axial region 13 and the diameter d3 of the outflow portion from the axial region 13 in the outlet 19 region are selected to be approximately the same size, so that a substantially cylindrical outlet hole with an axial region 13 exists.

[0034] When the diameter d3 of the outflow hole in the axial region 13 toward the outlet 19 is reduced, the ratio of the hole length L, i.e., the axial length of the axial region 13, to the outflow diameter d3 increases, and in this case, the jet stability, especially the jet velocity, increases. The following relationships are desirable for the above parameters: L / d2 ≥ 0.2; L / d3 ≥ 0.2; however, ideally, L / d3 ≥ 1.

[0035] Figures 4 to 9 show six other embodiments of flow-influencing geometry 10 generated via the inner contour 9 according to the present invention, which is flow-technically positioned downstream of the valve seat 3 in the cap-shaped mount 8. In this case, modifications in the regions of sections 12 and 13 of the cap-shaped mount 8 are proposed, in particular, to achieve the advantageous effects described above.

[0036] Figure 4 shows a solution in which the conicity of the hole exists in the axial region 13 of the inner contour 9. In this case, the angle k with respect to the conicity of the hole is 20°≧k≧2°. This allows the diameter d3 to be reduced by 5% to 50% relative to the diameter d2, corresponding to the hole length L.

[0037] Figure 5 shows a cap-shaped mounting body 8 in which an extremely large inclination angle α is selected for the conical extension portion 12. In this case, the angle α may be up to, for example, 85°. In this case as well, 5×I h ≥s ≥ 1.5 × I h It is desirable that the following relationship holds: This allows for virtually lossless flow around the end section 6 of the valve closing member 5. Due to the large angle α of the conical extension 12, this relationship is 3 × I h ≥s ≥ 1.5 × I h It can be shifted in that direction. The axial region 13 of the inner contour 9 may extend in a cylindrical or conical shape.

[0038] Figures 6 and 7 show two embodiments in which the outflow port is divided again in the axial region 13. In the configuration according to Figure 6, the initially cylindrical axial region 13 transitions abruptly to an end region 13a having a spherical bulge. The spherical bulge, which extends convexly when viewed from the inside, helps to form a flow that may be desired for certain integration characteristics and combustion chamber structure. The radius R of the spherical bulge in the end region 13a does not necessarily have to be constant.

[0039] In the configuration shown in Figure 7, the conical axial region 13 initially transitions below the bend to a similarly conical end region 13b, in which case the end region 13b has an angle k smaller than the angle k of the axial region 13. The conical axial region 13 may also transition to a cylindrical end region 13b, as shown in the figure. For areas A2 and A3 in the regions of diameters d2 and d3, it is desirable that 0.8 × A2 ≥ A3 ≥ 0.5 × A2 holds.

[0040] In the embodiment shown in Figure 8, the outflow hole is divided in the axial region 13. In this configuration shown in Figure 8, the cylindrical axial region 13 initially extends in a conical shape at the bend, and in this case transitions to an end region 13c that tapers in the direction of flow. The relationship between areas A2 and A3 can be similar in this case as well, corresponding to that described for Figures 6 and 7.

[0041] Figure 9 shows a cap-shaped mounting body 8 on which a modified valve closing member 5 is located. Its end section 6 has an additional flow-formed body 22 having a contoured portion directed downstream, which differs from the original disc-shaped shape. The flow-formed body 22 may be, for example, a needle tip formed into a conical or cylindrical shape at the center of the valve closing member 5. In order to form the flow-formed body 22 in a cylindrical or conical shape, it is desirable that the following conditions hold with respect to the diameter d2 at the inflow portion into the axial region 13: 2 / 3 × d2 ≥ b ≥ 1 / 3 × d2 (cylindrical); 2 / 3 × d2 ≥ b1; b2 ≥ 1 / 3 × d2 (conical). The illustrated configuration shows a flow-formed body 22 where the diameter b1 starting from the end section 6 of the valve closing member 5 corresponds to the diameter of the valve needle shaft upstream of the end section 6. However, this is only one possible configuration. Rather, the diameter b1 may be larger or smaller than the diameter of the valve needle shaft. The flow-formed body 22 may extend downstream, for example, starting from the radially outer contour of the end section 6 of the valve closing member 5.

[0042] In general, the flow-formed body 22 can be described as follows: On the lower surface of the downstream end section 6 of the valve closing member 5, an additional axial component element, which is not substantially disc-shaped, is attached to the valve closing member toward the downstream side. Thus, this additional axial component element is part of the geometry 10 that affects the flow.

[0043] The modified embodiments of the embodiments shown in Figures 3 to 8 relating to the inner contour 9 of the outflow hole having an axial region 13 may at any time be combined with the configuration of the valve closing member 5 with the flow-formed body 22 shown in Figure 9. The axial length of the flow-formed body 22 is such that the seal seat 7 is maximally open and thus the valve needle stroke l h When this is at its maximum, it must be shorter than the distance between the valve discs and the inflow portion into the axial region 13.

[0044] The flow-formed body 22 on the lower surface downstream of the valve closing member 5 enables flow stabilization of the internal flow immediately downstream of the valve disc, thereby reducing the force acting there. The influence on the valve needle in terms of rigidity is limited by the corresponding dimensions of the flow-formed body 22 as described above.

[0045] Furthermore, the proposed solution achieves a more flexible configuration of the hole design, which may be required, for example, in limited structural space. Thus, a greater degree of freedom is provided for various dimensions of the cap-shaped mounting body 8, in which case the outer diameter of the mounting body 8 in the area of ​​attachment to the nozzle body 2 is, for example, in the range of 8 mm to 15 mm, while the outer diameter of the mounting body 8 in the area of ​​the outlet 19 is, for example, in the range of 6 mm to 12 mm. These configurations can generally be supplemented or combined in various sub-embodiments with a radius R in the form of a rounded portion (see, for example, Figure 5) instead of a sharp, angular transition.

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, In an injector (1) having an axially movable valve closing member (5) for opening and closing at least one opening in a seal seat (7), an actuator (21) for operating the valve closing member (5), and a flow-influencing geometry (10) located downstream of the seal seat (7) in a flow-technically manner, Needle stroke (I ｈ When ) is at its maximum, 5 × I ｈ ≥ s ≥ 1.5 × I ｈ The following holds true, in which case (s) is the distance between the radially outer contour of the valve closing member (5) in the downstream edge region of the valve closing member and the annular line at the tapered portion (12) in the flow direction of the geometry (10) that affects the flow and is located below it in the projection view in the axial direction, thereby generating a virtually lossless flow downstream of the valve closing member (5), the injector (1).

2. The ratio is preferably 4 × I ｈ ≥ s ≥ 2.5 × I ｈ The injector according to claim 1, characterized in that it is the same as the injector according to claim 1.

3. The valve needle stroke (I ｈ ), when it is maximum, an annular seat cross-sectional area (A ｓ ) occurs between the valve seat (3) and the contact line of the valve closing member (5), and another annular area (A １ ) is defined by the interval resulting from the shortest distance between the outer contour of the valve closing member (5) at the downstream end of the valve closing member and the opposing wall of the tapered portion (12) in the flow direction of the geometry (10) that affects the flow, and in the ratio of the areas (A ｓ and A １ ), A １ ≧ 2.5 × A ｓ holds, and the injector according to claim 1 or 2 is characterized thereby.

4. At the end of the tapered portion (12) in the flow direction, there is an outflow hole that includes at least one axial region (13), thereby defining the entire inner contour (9) of the geometry (10) that affects the flow up to the outlet (19), and at the beginning of the axial region (13) the inner area (A ２ ) is defined, and the cross-sectional area of ​​the annular seat (A ｓ Regarding the following, namely, 5 × A ｓ ≧A ２ ≥ 2 × A ｓ The injector according to claim 3, characterized in that the following holds true.

5. The injector according to claim 4, characterized in that the outflow hole has an axial region (13) divided into a plurality of subsections.

6. The injector according to claim 4 or 5, characterized in that the axial region (13) of the outflow hole, which continues downstream of the tapered portion (12) in the flow direction, extends in a cylindrical shape or similarly tapers and extends.

7. The injector according to any one of claims 4 to 6, wherein the outflow hole has downstream end regions (13a, 13b, 13c) leading to the outlet (19), and the end regions are formed in a cylindrical shape, or are formed to taper to a conical shape or curved to a spherical shape.

8. The diameter (d) of the axial region (13) of the outflow hole in the region of the outlet (19) ３ ) is the diameter (d) at the starting portion of the axial region (13). ２ The injector according to any one of claims 4 to 7, characterized in that it is less than or equal to the following.

9. The injector according to any one of claims 1 to 8, characterized in that the tapered portion (12) in the flow direction of the geometry (10) that affects the flow extends in a substantially conical shape downstream of the valve closing member (5).

10. The injector according to any one of claims 1 to 9, characterized in that the tapered portion (12) in the flow direction of the geometry (10) that affects the flow has an inclination angle α downstream of the valve closing member (5) of 85° ≥ α ≥ 30°, preferably an inclination angle α greater than 45°.

11. The injector according to any one of claims 1 to 10, characterized in that the flow-influencing geometry (10), which is positioned downstream of the seal seat (7) from a flow technology perspective, is realized in the cap-shaped mounting body (8), particularly in the blow cap.

12. The injector according to claim 11, characterized in that the cap-shaped mounting body (8) can be attached to the injection-side end of the injector (1), particularly to the nozzle body (2).

13. The injector according to any one of claims 1 to 12, characterized in that the valve closing member (5) is a portion of an axially movable valve needle, and the valve closing member (5) has an end section (6) that is formed in a substantially disc shape.

14. The injector according to claim 13, wherein a flow-molded body (22) is formed on the lower surface of the downstream end section (6) of the valve closing member (5), and the flow-molded body has a substantially disc-like shape with additional axial component elements attached downstream, wherein the additional axial component elements are parts of the geometry (10) that affect the flow.

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