INJECTOR FOR INJECTING A FLUID AND MANUFACTURING METHOD FOR SUCH AN INJECTOR

Description

State of the art

[0001] The present invention relates to an injector for injecting a fluid, in particular a so-called vortex injector, and to a method for producing such an injector.

[0002] The injector according to the invention is preferably a fuel injector, in particular a gasoline injector, or a water injector or a urea injector.

[0003] Injectors are known in the art in various designs. For example, DE 10 2006 057 279 A1 shows an injector with a spray hole plate that is electroformed. Particularly in gasoline injectors or water injectors in the low-pressure range (up to 100 x 105 Pa), injectors with multiple spray holes are used to ensure the best possible atomization of the fluid to be injected. However, this can result in a complex injector geometry. The different geometric parameters, however, significantly influence the flow rate and angle of the spray generated in the injection chamber, particularly the combustion chamber of an internal combustion engine. The best possible atomization of the injected fluid should be enabled for the most complete combustion possible and to comply with emissions regulations.The documents DE 10 2013 202 784 A1, JP 2012 077665 A and EP 3 273 049 A1 describe fuel injection valves with a spray hole component which has swirl chambers on the inside and recesses on the spray holes on an outside. Disclosure of the invention

[0004] The injector according to the invention for injecting a fluid with the features of claim 1 has the advantage that a very fine atomization of the fluid to be injected, in particular gasoline or water, is reliably possible. This is particularly preferably possible in a low-pressure range of less than 100 x 105 Pa. According to the invention, a very good atomization of the fluid to be injected is made possible without an increase in the injection pressure. The injector according to the invention can be manufactured very simply and cost-effectively. Furthermore, a target angle of a substantially conical spray in the injection chamber can be made possible in a simple and reliable manner. This is achieved according to the invention in that the injector has a closing element which opens and closes a fluid passage at a valve seat. Furthermore, a spray hole component with a plurality of spray holes is provided.The spray hole component is, for example, a spray hole plate or a pot-shaped component, each of which has a plurality of, in particular cylindrical, spray holes, for example four or six. Vortex chambers are formed around the spray holes on an inner side of the spray hole component facing the closing element. The vortex chambers on the inner side of the spray hole component can impart a predetermined swirl to the emerging spray. On an outer side of the spray hole component facing away from the closing element, a material reduction region is formed on each spray hole to reduce the thickness of the spray hole component. This allows a precise adjustment of the length of the spray hole, in particular a cylindrical length.By precisely maintaining the axial length of the spray hole, particularly with minimal tolerance, compliance with the predetermined angle of a spray cone and particularly fine atomization of the fluid to be injected can be ensured. The spray hole is preferably completely cylindrical. Since the spray hole length is adjusted on the outside of the spray hole component, the inside of the spray hole component, which has the swirl chambers and optionally channels or the like, can be provided, for example, in a single step using a forming process. The spray hole length can then be adjusted exclusively on the outside of the spray hole component. The internal geometry of the spray hole component is not affected by the adjustment of the spray hole length. The material reduction area is provided as a machined area.The material reduction area is provided by a machining process, for example milling or grinding or the like.

[0005] The spray hole component is preferably a spray hole plate or a pot-shaped spray hole component. The valve seat of the injector is preferably also arranged on the spray hole component. The swirl chambers are produced on the inside of the spray hole component by a forming process, in particular by stamping or pressure forming. Further preferably, the spray hole component has channels extending from a point through which a central axis of the injector runs, which channels lead to the individual swirl chambers at the spray holes. The channels are preferably linear.

[0006] The subclaims show preferred developments of the invention.

[0007] Preferably, the material reduction region is formed partially or completely around the spray hole. A material reduction region that completely surrounds the spray hole can be manufactured very easily. However, it has also been found that improved atomization can also be achieved by providing the material reduction region only partially around the spray hole, for example, in a circumferential area of ​​50% or more of the total circumference, in order to achieve significant improvements in spray atomization.

[0008] The injector is preferably a gasoline injector or a water injector or a urea injector.

[0009] Furthermore, the present invention relates to a method for producing a spray hole component of an injector for introducing a fluid with the features of claim 3.

[0010] The method according to the invention can be carried out very simply and cost-effectively, so that the manufacturing costs for such a spray hole component can be kept very low. The method comprises the steps of producing a plurality of, in particular cylindrical, spray holes in the spray hole component with a swirl chamber formed on an inner side of the spray hole component. In a subsequent step, an outer side of the spray hole component is then machined at an outlet region of the spray holes on the outside in such a way that a length of the spray holes is adjusted by material reduction. The final length of the spray holes is thus determined exclusively by machining on the outer side of the spray hole component. This eliminates the need for machining on the inner side of the spray hole component, on which the swirl chambers and any supply channels or the like are formed.This avoids the risk of damage to the sometimes complex geometry on the inside of the injection hole component, since, according to the invention, the length of the injection hole is determined exclusively by machining on the outside. The length of the injection holes is preferably adjusted in a single process step. The outside of the injection-molded component is machined using a machining process to adjust the length of the injection holes. The machining process can be, for example, milling or grinding or the like.

[0011] Preferably, the spray holes at the outlet area on the outside of the spray hole component are machined only on a partial circumference of the outlet area or alternatively on the entire circumference of the outlet area.

[0012] According to an alternative embodiment of the invention, an expanding region is formed at the outlet region of the spray hole, in particular a conically expanding region, whereby a length of the spray holes is adjusted.

[0013] Particularly preferably, the injection hole component is manufactured in a first step by deep drawing to produce a swirl path, in particular supply channels, as well as to form a basic internal geometry of the injection hole component. In a second, subsequent step, the swirl chambers are formed. The injection holes are then introduced, for example, by a machining process such as drilling or using a laser. In the final step, the outer side of the injection hole component is machined to create the material reduction areas at the exit areas of the injection holes.

[0014] The injection-hole component produced by the method according to the invention has, in particular, no negative impact on the flow rate through the injection holes, since no changes are made to the injection holes themselves, in particular the diameter, or to the internal geometry of the injection-hole component. In particular, an existing tool for forming the internal geometry of the injection-hole component does not need to be modified. Short description of the drawing

[0015] Preferred embodiments of the invention are described in detail below with reference to the accompanying drawings. In the drawing: Figure 1 shows a schematic sectional view of an injector with a spray hole component according to a first preferred embodiment of the invention, Figure 2 shows a schematic representation of an inside of the spray hole component of Figure 1, Figure 3 a schematic representation of an outer side of the spray hole component of Figure 1 , Figure 4 a schematic partial sectional view of the injection hole component of Figure 1 , Figure 5 is a schematic external view of a spray hole component according to a second embodiment of the invention, and Figure 6 is a schematic partial sectional view of the spray hole component of Figure 5 . Preferred embodiments of the invention

[0016] The following is based on the Figures 1 to 4 an injector 1 according to a first preferred embodiment of the invention is described in detail.

[0017] The injector 1 of this embodiment is a fuel injector.

[0018] The injector 1 comprises a magnetic actuator 20 and a closing element 2 in the form of a closing needle. A ball 21 is provided at the free end of the closing needle, which opens and closes a fluid passage at a valve seat 5 in a known manner.

[0019] In this embodiment, the valve seat 5 is formed on a component connected to a spray hole component 3. The spray hole component 3 has a plurality of cylindrical spray holes 4. In this embodiment, exactly four spray holes 4. Furthermore, the spray hole component 3 is designed as a disk. As can be seen from Figure 1 As can be seen, the spray hole component 3 is connected to a valve housing 21.

[0020] Figure 2shows a view of an inner side 6 of the spray hole component 3. In this case, vortex chambers 40 are formed around the spray holes 4, which impart a swirl to the fluid to be injected, so that when the fluid to be injected exits, the spray cone produced spreads with swirl or vortex-like in the injection chamber.

[0021] Furthermore, linear channels 41 are formed on the inner side 6, which extend from a central axis XX of the injector. Each channel 41 leads to a swirl chamber 40, which, as can be seen from Figure 2 as can be seen, is slightly bent at a predetermined angle in the circumferential direction of the injector.

[0022] The spray holes 4 are formed in the middle of the swirl chambers 40.

[0023] Figure 3shows an outer side 7 of the injection hole component according to the first embodiment of the invention. On the outer side 7, the channels and swirl chambers produced by stamping are formed from the inside in negative form. Furthermore, a material reduction region 8 is formed at an outlet area of ​​each injection hole 4. The material reduction region 8 is shown in detail in the sectional view of Figure 4 visible.

[0024] As shown in detail Figure 4 As can be seen, a normal thickness of the spray hole component is designated by reference numeral 9. In the area of ​​the spray hole 4, the spray hole component 3 has a reduced thickness, which is reduced by the material reduction 11. The spray hole 4 is arranged in this area. This allows a cylindrical length 10 of the spray hole 4, which is cylindrical, to be adjusted.

[0025] A predetermined cylindrical length of the spray hole 4 is thus produced exclusively by machining the spray hole on the outer side 7.

[0026] The material reduction region 8 is a region produced by a machining process, an eroding process, or an etching process. Preferably, all material reduction regions 8 at the injection holes 4 are produced simultaneously in one step.

[0027] As from Figure 4 As can be seen, the material reduction 11 in this embodiment is approximately 20% of the thickness 9 of the injection hole component.

[0028] The spray hole component 3 can thus be manufactured by the method according to the invention such that, in a first step, the inner side 6 of the spray hole component 3 and the cylindrical spray holes 4 are manufactured, and in a final step, the outer side 7 is machined in order to adjust a cylindrical length 10 of the spray hole 4 in one step by reducing material at the material reduction region 8. The inner side 6 can, for example, first be manufactured by deep-drawing the spray hole component 3 to produce a basic internal geometry 43 and a subsequent forming step, for example by embossing on the inner side 6 to produce the swirl chambers 14 and the channels 41.Subsequently, the spray holes 4 can be introduced into the center of the swirl chambers 40 and, in a final, individual step, the outer side 7 of the spray hole component 3 can be machined in order to produce the exact length 10 of the spray holes by reducing the material on the outer side 7.

[0029] The method according to the invention can be implemented very simply and cost-effectively. The spray hole component 3 produced in this way enables excellent atomization of the fluid to be injected by precisely maintaining the length 10 of the spray hole 4, without negatively affecting the flow rate through the spray holes 4. By precisely maintaining the length 10 of the spray holes 4, a cone angle of the fluid to be injected in the injection chamber, for example, a combustion chamber of an internal combustion engine with a direct injection injector, can also be precisely maintained.

[0030] Figures 5 and 6show a spray hole component 3 according to a second embodiment of the invention. Identical or functionally identical parts are designated by the same reference numerals as in the first embodiment.

[0031] As is particularly evident from Figure 6 As can be seen, the spray hole component 3 of the second exemplary embodiment has a different material reduction region 8. In this second exemplary embodiment, the material reduction region 8 is formed by a conically widening region 42 at the outlet region of the spray hole 4. The conically widening region 42 does not have to be formed completely around the outer region of the spray hole 4; rather, to achieve the objectives of the invention, it is sufficient if the conical region 42 is only partially produced around the spray hole at the outlet region.

Claims

1. Injector for injecting a fluid, comprising: a closing element (2), which opens up and closes a fluid passage on a valve seat (5), and - an injection-hole component (3) having a multiplicity of injection holes (4), - wherein, on an inner side (6) of the injection-hole component (3) directed towards the closing element (2), vortex chambers (40), which are provided by a forming process, are formed on the injection holes (4), - the injector is characterized in that, on an outer side (7) of the injection-hole component (3) facing away from the closing element (2), a material reduction region (8) for reducing a thickness (9) of the injection-hole component (3) is formed on the injection hole (4) in order to adjust a length (10) of the injection hole (4), and - in that the material reduction region (8) is designed as a machined region, which is provided by a machining process.

2. Injector according to Claim 1, wherein the material reduction region (8) is formed partially or completely around the injection hole (4).

3. Method for producing an injection-hole component (3) of an injector for injecting a fluid, comprising the steps of: - producing a multiplicity of injection holes (4) with vortex chambers (40) formed on an inner side (6) of the injection-hole component (3), wherein the vortex chambers (40) on the inner side of the injection-hole component (3) are produced by a forming process, the method is characterized in that an outer side (7) of the injection-hole component (3) at the outlet region of the injection holes (4) is machined in such a way that a length (10) of the injection hole (4) is adjusted by material reduction, - wherein the outer side (7) of the injection-hole component (3) is machined by a machining process in order to adjust the length (10) of the injection holes (4).

4. Method according to Claim 3, wherein the injection holes (4) at the outlet region are machined only on a partial circumference of the outlet region or wherein the injection holes at the outlet region are machined on the full circumference of the injection holes.

5. Method according to Claim 3 or 4, wherein an expanding region (42), in particular a conically expanding region, is in each case formed at the outlet region of the injection holes (4).