EP0694124A1

EP0694124A1 - Venturi filter and fuel injection valve with a venturi filter

Info

Publication number: EP0694124A1
Application number: EP95903245A
Authority: EP
Inventors: Martin Maier; Jürgen Buchholz; Jörg HEYSE; Michael Klaski; Edwin Liebemann; Klaus Wirth; Mathias Thomas; Klaus-Henning Krohn; Jutta Straetz; Stefan Lauter; Christof Dennerlein; Anwar Abidin
Original assignee: Robert Bosch GmbH
Current assignee: Robert Bosch GmbH
Priority date: 1993-12-21
Filing date: 1994-12-20
Publication date: 1996-01-31
Anticipated expiration: 2014-12-20
Also published as: DE59407970D1; US5707012A; CN1118181A; JP3512807B2; WO1995017595A1; BR9406147A; ES2131299T3; EP0694124B1; JPH08507118A; CN1050649C

Abstract

Fuel injection valves with venturi filters (50) for supplying fuel or fuel/gas mixtures to internal combustion engines are characterised in that they ensure a particularly high spray quality and remarkable fuel conditioning. In addition, the venturi filter (50) forms a protection screen against icing, plugging and deposits of chemical substances inside the fuel injection valve. The venturi filter (50), which has a shell-shaped, concave bulging form, is mounted downstream of at least one injection hole (15), seen in the fuel flow direction. The outer circumferential area (60) of the venturi filter (50) is cast into the protective cap (40) provided at the downstream end of the fuel injection valve. The protective cap (40) has protective teeth (62) that extend further downstream than the deepest area (56) of the venturi filter (50), in order to protect it against mechanical influences. When fuel is injected, a partial amount of fuel gathers in said deepest area (56) and forms a relatively still amount of liquid, to which new fuel is added. This arrangement allows ideal spraying of fuel in smallest droplets.

Description

Atomizing screen and fuel injector with one atomizing screen

State of the art

The invention is based on an atomizing sieve or a fuel injection valve with an atomizing sieve according to the type of patent claim 1 or of patent claim 10.

From DE-OS 23 06 362 a device for

Fuel preparation for an internal combustion engine is known, in which fuel is metered in with at least one injection valve, which in turn strikes a strainer arranged there in an intake pipe downstream of the injection valve or a branch nozzle of the intake pipe. This device is intended to produce an easily ignitable fuel-air mixture, especially during the cold start and warm-up phase of the internal combustion engine, without having to significantly increase the fuel quantity. Good pre-evaporation of the fuel occurs when the strainer is designed to be electrically heated. The large distance of the sieve from the injection valve does not allow precisely targeted jet shapes, but rather the Fuel sprayed widely.

Also known from EP-OS 0 302 660 is a fuel injection valve, at the downstream end of which an adapter is provided, into which an adapter is provided

Coming fuel outlet comes, which in turn meets at the downstream end of the adapter on a flat, meshed metal disc to break up the fuel. The flat metal disc is arranged so that an air flow through holes in the adapter upstream of the metal disc and downstream of the metal disc ensures that fuel drops stuck to the metal disc are torn away. A better atomization quality is only achieved when the fuel is surrounded by an air stream near the metal disc, but through which an accurate spray geometry cannot be achieved.

In addition, it is already known from DE-OS 27 23 280, one downstream of a fuel injector

Dosing opening to perform a fuel breaker in the form of a flat thin disc having a plurality of curved narrow slots. The arcuate slots, which are made by etching in the disk, ensure with their geometry, that is to say with their radial width and their arc length, that a fuel veil is formed which breaks up into small droplets. The etching process for producing the slots is very cost-intensive. In addition, the individual slot groups must be introduced very precisely in order to achieve the desired breakdown of the fuel. Advantages of the invention

The atomizing screen according to the invention with the characterizing features of claim 1 has the advantage that it is very simple and easy to assemble on fuel injection valves, very inexpensive and in a variety of

Design variants can be produced quickly and safely and ensures excellent atomization of the sprayed fuel.

Advantageous further developments and improvements of the atomizing sieve specified in claim 1 are possible through the measures listed in the subclaims.

It is particularly advantageous to design the atomizing sieve to be curved in the form of a bowl. It is also advantageous to manufacture the atomizing sieve from a rustproof metal, a plastic, Teflon or PTC, i.e. a material with a positive resistance-temperature coefficient. Teflon is particularly suitable as a material for the atomizing sieve when the atomizing sieve is to be used under extreme temperature conditions. A Teflon atomizing sieve is hydrophobic and therefore prevents icing at temperatures down to -40 ° C.

A particularly advantageous embodiment of the atomizing sieve results if a mesh size of approximately 0.2 mm of the sieve is provided. It can also be advantageous for special applications to produce the meshes of the atomizing sieve in two or more layers in addition to a single-layer variant, the multiple fabric layers being interlaced with one another. The mesh density can advantageously be used to adjust the area Atomization quality can be designed variably. The fabric of the atomizing sieve can have a constant mesh size, but can also become denser towards the outer zone of the sieve or, conversely, can also be compressed towards the center of the atomizing sieve.

Furthermore, it is advantageous to design the atomizing sieve as a bimetal sieve, consisting of two metals with different coefficients of thermal expansion, by introducing the mesh openings, for example by means of a laser. A bimetal sieve has the advantage that the geometry of the sieve, that is, for. B. the bulge shape, can be changed at different operating temperatures in a desired manner to the atomization quality and the jet shape

Adapt the requirements of the respective operating conditions.

A heatable atomizing sieve for fuel vaporization is also advantageous. Temperature-dependent sieve materials ensure that the resistance is variable. So z. B. in PTC materials with a positive resistance-temperature coefficient of resistance when heated. As a result, better evaporation of the fuel can be achieved by electrical heating, in particular when the internal combustion engine is cold started.

Another advantage is a circumferential clamping ring that limits the atomizing sieve in the circumferential direction and in which the sieve blade is clamped, clamped or cast around. This clamping ring enables a very simple assembly of the atomizing screen on a fuel injector, which can be done in one process step by clamping.

The fuel injector according to the invention with the Characteristic features of claim 10 has the advantage that an atomizing screen is very easy to mount on the fuel injector at very low cost, which contributes to a further improvement in the atomization quality even without gas containment, since the fuel striking the atomizing screen is particularly fine on the mesh of the atomizing screen is atomized into tiny droplets, which further reduces the exhaust gas emission of an internal combustion engine and also reduces fuel consumption. The fuel is extremely slowed down by the impact on the atomizing sieve and diverted into the respective mesh. The collision causes the fuel to tear apart or dismember. An energy conversion of the kinetic energy stored in the fuel therefore takes place in the area of the atomizing sieve. Vibrations and turbulence occur in the now finely shredded fuel due to the collision. The prerequisite for this is at least an impulsive fuel jet, which can emerge, for example, from a nozzle opening or from a plurality of spray openings of an orifice plate. By tearing the fuel on the atomizing sieve and passing the fuel through the fine mesh of the atomizing sieve, a fine droplet mist is created downstream of the atomizing sieve. The

Fuel droplets now have a significantly larger surface area than the fuel jets before they hit the atomizing screen, which in turn is an indication of good atomization.

In addition to an optimized atomization and a reduction in the exhaust gas emission and the fuel consumption of the internal combustion engine associated therewith, the characteristic features of claim 10 result in further advantages and positive effects. So that offers atomization Sie downstream of the nozzle opening or the spray hole disk increased security against icing inside the fuel injection valve, especially the spray hole disk. With a fuel injection valve according to the invention, fuel can be sprayed off at significantly lower temperatures (even with high air humidity) than is the case with fuel injection valves without an atomizing sieve. The atomizing sieve acts as an "ice trap". In addition, the atomizing sieve on the fuel injector

The risk of so-called plugging on the spray nozzle is considerably reduced. Bad quality fuel has namely. a. also heavy-boiling components that lead to tar residues on the fuel injector in known fuel injection valves in contact with the intake manifold atmosphere. The consequences are cross-sectional reductions in the fuel outlet openings, which can even lead to clogging. With the downstream arrangement of the atomizing sieve, this disadvantageous process is excluded, since the

Intake manifold atmosphere is kept away from the fuel outlet openings and therefore these components of the fuel are already deposited on the atomizing screen. A possibly added atomizing sieve can be exchanged very easily. In addition to preventing plugging, lead sulfate is also prevented from being deposited on the nozzle orifice or spray plate. Sulfur-containing fuels have the disadvantage that when they hit colder components, sulfur condenses, which means that layers of

Deposit lead sulfate on metallic components. Similar to plugging, these layers cause openings on the fuel injection valve to become clogged, for example the spray openings of the spray nozzle. The atomizing sieve effectively ensures that no lead sulfate layers are formed upstream of the atomizing sieve in the interior of the fuel injector, since the chemical intake pipe atmosphere is not effective there.

The atomizing screen attached to the fuel injector is therefore both a

Atomizing improver of the fuel emerging from the fuel injection valve and also a protective element against numerous influences of a mechanical and chemical nature.

Advantageous further developments and improvements of the fuel injector specified in claim 10 are possible through the measures listed in the subclaims.

It is particularly advantageous to design the atomizing sieve to have a concave, dish-shaped configuration as seen in the flow direction of the fuel. The concave bulge of the atomizing sieve ensures that part of the deposited fuel can converge in at least one deepest area. The collected

For a short time, fuel represents a comparatively static amount of liquid, which is then hit by new fuel. This configuration contributes to a particularly high atomization quality. In addition, no fuel can collect on the outer sieve rim.

It is also advantageous if the atomizing sieve is cast into a protective cap with an outer peripheral region. The atomizing sieve is embedded in the protective cap with a backward measure, ie the downstream cap end of the protective cap delimits the fuel injector downstream, while the deepest region of the atomizing sieve lies further upstream and thus does not protrude from the fuel injector. This spatial arrangement offers one adequate protection against mechanical damage. The protective cap is advantageously designed as a protective crown, which results in advantages in the dripping behavior of the fuel injector compared to a protective cap with a circumferential protective ring.

The formation of several bulges on the atomizing screen results in further advantages, since very specific jet geometries or jet images can be generated for different applications. The jet angles of the fuel specified by the spray hole arrangement or inclination are advantageously retained even when the atomizing sieve is connected downstream. One through the spray openings z. B. Predetermined double radiation is not negatively influenced by the atomizing sieve, but can be increased by expensive upstream or downstream of the atomizing sieve arranged jet.

A gas containment of the fuel which is additional to the atomizing sieve is particularly advantageous. The gas supply can be arranged so that the gas is directed towards the fuel both upstream and downstream of the atomizing sieve. Ideally, the gas supply channels are introduced downstream of the atomizing sieve in the protective cap and are aligned in such a way that their imaginary extensions tangentially touch the bulge of the atomizing sieve downstream. The treatment quality is further increased by the gas enclosure. In addition to improving the atomization of the fuel by a downstream gas supply, there is also the advantage of very low costs, since the supply channels can be introduced very easily into the protective cap and on a gas which is difficult to adjust with regard to the accuracy of the gas quantity. annular gap can be dispensed with. Desired fuel jet angles are largely retained despite the gas enclosure, since the fuel is not fully encompassed by the gas emerging from the supply channels.

The very simple and good handling is of great advantage, since the atomizing sieve forms, together with the protective cap, a preparation attachment which can be placed on the most varied types of valves and can therefore also be used independently of valve closing element shapes.

It is particularly advantageous to arrange the atomizing screen downstream with a clear spatial distance from the at least one spray opening of the injection valve. The aim is namely to place the point of fuel atomization in the ideal position in the air flow of the intake manifold of the internal combustion engine with an atomizer attachment consisting of a spacer and the atomizing sieve when the injection valve is in a fixed installation position, so that the wall film formation of the fuel in the intake manifold is reduced or increased prevent, as a consequence of which a significant reduction in the exhaust gas emission, in particular the proportion of HC, is achieved. The spacer body with the atomizing sieve, which is advantageously attached to its downstream end, thus ensures a spatial separation of metering and preparation of the fuel. 5 - 50 mm (without gas) or 5 - 100 mm (with gas) have proven to be ideal distances between the spray opening and the atomizing sieve. Ideally, the dimensions (diameter, length) of the best sleeve-shaped spacer can be easily changed and adapted to differently shaped suction tubes that the atomization and Processing of the fuel, for example, can always take place in the middle of the intake manifold flow, thus largely avoiding the aforementioned wall film formation in the intake manifold.

In order to prevent disturbing wetting of the inner wall of the spacer body, the injection valve must spray a fuel jet with the smallest possible opening angle, that is to say a so-called pencil jet-shaped jet. It is advantageous if openings are therefore provided in the spacer near the spray opening, through which gas is introduced in order to leave the fuel jet in the form of a cord over the length of the spacer. According to the principle of the water jet pump, namely because of the

Fuel jet through the openings z. B. intake manifold air sucked. The sucked-in air surrounds the cord-shaped fuel jet, so that disadvantageous wetting of the inner wall of the spacer body is avoided. The dripping of fuel with the injector switched off can be largely prevented by this measure. A gas flow generated by an additional gas inlet also ensures an improved discharge behavior of the fine fuel droplets.

Advantageously, a large number of atomizer arrangements can be created by combining differently shaped atomizing sieves and spacers having different dimensions in connection with or without gas introduction, with or without gas enclosure on the atomizing sieve, with or without a beam splitter, which can be connected upstream or downstream of the atomizing sieve are each matched to the specific conditions of the intake manifold and the internal combustion engine. With the help of this Atomizer attachments on the injection valves are also very easy to achieve special forms of fuel spraying (e.g. elliptical spray patterns, asymmetrical quantity distribution, spraying onto several intake valves).

Further advantages are mentioned below in the description of the exemplary embodiments.

drawing

Embodiments of the invention are shown in simplified form in the drawing and explained in more detail in the following description. 1 shows a first exemplary embodiment of a fuel injection valve with an atomizing sieve, FIG. 2 shows a second exemplary embodiment of a fuel injection valve with an atomizing sieve, FIG. 3 shows a third exemplary embodiment of a fuel injector with an atomizing sieve, FIG. 4 shows a schematic diagram of a atomizing sieve with a bulge, 5 shows a schematic diagram of an atomizing sieve with four bulges, FIG. 6 shows a schematic diagram of a atomizing sieve with two symmetrical bulges, FIG. 7 shows a schematic diagram of a atomizing sieve with two asymmetrical bulges, FIG. 8 shows a schematic diagram of an atomizing sieve with two annular bulges fourth exemplary embodiment of a fuel injection valve with an atomizing sieve and a jet splitter, FIG. 10 shows an atomizing sieve with an integrated jet part FIG. 11 shows a fifth exemplary embodiment of a fuel injector with an atomizing sieve with upstream gas supply via an annular gap, FIG. 12 shows a sixth exemplary embodiment of a fuel injector with an atomizing sieve 13 shows a seventh exemplary embodiment of a fuel injector with an atomizing sieve with downstream gas supply via supply channels, FIG. 14 shows a first schematic diagram of the arrangement of the supply channels, FIG. 15 shows a second schematic diagram of the arrangement of the supply channels, FIG. 16 shows a third 17 shows an eighth exemplary embodiment of a fuel injection valve with two atomizing sieves and an interposed gas supply, FIG. 18 shows an atomizing sieve with a square mesh, FIG. 19 shows an atomizing sieve with a multi-layer fabric pattern, FIG. 20 shows an atomizing sieve with tissue compressed towards the center, FIG. 21 an atomizing sieve with tissue compressed toward the outer sieve zone, FIG. 22 an atomizing sieve in the form of a perforated body, FIG. 23 an atomizing sieve with tightly tensioned wires in a groove Figure 24 shows a first example of a spacer body with atomizing screen attached to the fuel injection valve, Figure 25 shows an enlarged view of the atomizing screen from Figure 24, Figures 26 and 27 positive and negative conical atomizing screens, Figure 28 shows a second example of a spacer body, Figure 29 shows a third example a spacer, Figure 30 shows a section along the line XXX-XXX in Figure 29, Figure 31 shows a fourth example of a spacer, Figure 32 shows a section along the line XXXII-XXXII in Figure 31, Figure 33 shows a fifth example of a spacer, Figure 34 shows a Section along the line XXXIV-XXXIV in Figure 33, Figure 35 shows a sixth example of a spacer, Figure 36 shows a seventh example of a spacer, Figure 37 shows an eighth example of a spacer with a Venturi nozzle, Figure 38 shows a ninth example of a spacer, Figure 39 only a little convex atomizing sieve, Figure 40 a two-part atomizing sieve, FIG. 41 an atomizing sieve with partial change in mesh size, FIG. 42 a tenth example of a spacer body with two atomizing sieves, FIG. 43 an eleventh example of a spacer body and FIG. 44 a twelfth example of a spacer body with a Venturi nozzle.

Description of the embodiments

1 shows, as a first exemplary embodiment, a valve in the form of an injection valve for fuel injection systems of mixed-compression spark-ignition internal combustion engines with an atomizing sieve according to the invention. The injection valve has a tubular valve seat support 1, in which a longitudinal opening 3 is formed concentrically with a valve longitudinal axis 2. In the longitudinal opening 3 is a z. B. tubular valve needle 5 arranged at its downstream end 6 with a z. B. spherical valve closing body 7, on the circumference of which, for example, five flats 8 are provided, is connected.

The injection valve is actuated in a known manner, for example electromagnetically. An indicated electromagnetic circuit with a magnet coil 10, an armature 11 and a core 12 is used for the axial movement of the valve needle 5 and thus for opening against the spring force of a return spring (not shown) or closing the injection valve. The armature 11 is connected to the valve needle 5 and aligned with the core 12. The magnetic coil 10 surrounds the core 12, which represents the end of an inlet connection, not shown in more detail, which serves to supply fuel.

To guide the valve closing body 7 during the Axial movement is provided by a guide opening 15 of a valve seat body 16. In the downstream end of the valve seat carrier 1 facing away from the core 11, the cylindrical valve seat body 16 is tightly mounted in the longitudinal opening 3, which is concentric to the longitudinal axis 2 of the valve, by welding. On its one, the valve closing body 7 facing away from the lower end face 17, the valve seat body 16 with a z. B. cup-shaped spray plate 21, for example, by a laser-formed first weld 22 concentrically and firmly connected so that the spray plate 21 abuts with its upper end face 19 on the lower end face 17 of the valve seat body 16. At least one, for example four, spray openings 25 formed by eroding or stamping are located in the central region 24 of the spray orifice plate 21.

A circumferential holding edge 26 of the spray plate 21, which extends away from the valve seat body 16 in the axial direction, is conically bent outwards up to its end. This means that there is only radial pressure between the longitudinal opening 3 and the slightly conically outwardly bent retaining edge 26 of the spray-perforated disk 21. At its end, the holding edge 26 of the spray plate 21 with the wall of the longitudinal opening 3, for example, by a circumferential and dense, for. B. connected by a laser formed second weld 30.

The insertion depth of the existing valve seat body 16 and cup-shaped spray orifice plate 21

The valve seat part in the longitudinal opening 3 determines the presetting of the stroke of the valve needle 5, since the one end position of the valve needle 5 when the solenoid 10 is not energized due to the valve closing body 7 resting on a valve seat surface 29 of the valve seat body 16 is set. The other end position of the valve needle 5 is determined when the solenoid 10 is excited, for example by the armature 11 resting on the core 12. The path between these two end positions of the valve needle 5 thus represents the stroke.

The spherical valve closing body 7 interacts with the valve seat surface 29 of the valve seat body 16 which tapers in the shape of a truncated cone, which is formed in the axial direction between the guide opening 15 and the lower end face 17 of the valve seat body 16. The fuel enters the valve seat body 16 from a valve interior 35 which is delimited in the radial direction by the longitudinal opening 3 of the valve seat carrier 1 and flows along in the guide opening 15 up to

Valve seat surface 29. In order that the flow of the fuel also reaches the spray openings 25 of the spray orifice plate 21, for example five flats 8 are introduced on the circumference of the spherical valve closing body. The five circular flats 8 allow the fuel to flow through in the open state of the injection valve from the valve interior 35 to the spray openings 25 of the spray plate 21.

A protective cap 40 is arranged on the periphery of the valve seat support 1 at its downstream end facing away from the solenoid 10 and is connected to the valve seat support 1 by means of, for example, a snap-in connection. A sealing ring 41 is used to seal between the circumference of the injection valve and one, not shown

Valve recordings, for example the intake line of the internal combustion engine.

An atomizing sieve 50a according to the invention is arranged downstream of the spray perforated disk 21 is arched out, for example, in the form of a bowl, a bulge 51 being provided in a concave manner as seen in the flow direction of the fuel. The atomizing sieve 50a, which is preferably made of a stainless metal, is delimited in the circumferential direction by a circumferential clamping ring 52, in which the metallic fabric of the atomizing sieve 50a is clamped, clamped or molded.

The clamping ring 52 enables the atomizing sieve 50a to be assembled very easily, since the entire sieve arrangement comprising the atomizing sieve 50a and the clamping ring 52 can be clamped between the valve seat carrier 1 and the protective cap 40 in one process step. For this purpose, either the atomizing sieve 50a with the clamping ring 52 can be pressed with a tool against the downstream end of the valve seat carrier 1 and the protective cap 40 can be pushed over the clamping ring 52 onto the valve seat carrier 1 until the locking connection between the protective cap 40 and the valve seat carrier 1 is established or the atomizing sieve 50a with the clamping ring 52 is inserted directly into an inner groove 53 of the protective cap 40 and fastened together with the protective cap 40 to the valve seat support 1, the clamping ring 52 being completely between the downstream end of the valve seat support 1 and the when the locking connection between the protective cap 40 and the valve seat support 1 is reached Protective cap 40 is clamped.

That from the at least one spray opening 25 of the spray plate 21, for example from four

Spray openings 25, emerging fuel jets collide downstream of the spray orifice plate 21 on an inner screen surface 55 of the bulging atomizing screen 50a. The collision or impact of the fuel on the atomizing sieve 50a represents a particular problem effective treatment method, in which atomization takes place in particularly small droplets. The impact of the fuel on the inner screen surface 55 has the consequence that the fuel is extremely slowed down and deflected into the respective meshes of the atomizing screen 50a. Just the collision on the atomizing sieve .50a causes the fuel to tear or dice apart. Inevitably, an energy conversion takes place in the region of the atomizing sieve 50a in the form of a jet from the spray openings 25

Spray plate 21 emerging fuel stored kinetic energy instead, in which now finely torn vibrations and turbulence due to the collision occur.

The aim of this type of treatment is to spray particularly finely atomized fuel in the form of tiny droplets from the injection valve in order, for example, to achieve very low exhaust gas emissions from the internal combustion engine and to reduce fuel consumption. With the

Atomizing sieve 50a can meet this requirement in a particularly advantageous manner. This is because a fine droplet mist is created downstream of the atomizing sieve 50a by tearing the fuel on the atomizing sieve 50a and passing the fuel through the fine meshes of the atomizing sieve 50a. These particularly small fuel droplets forming the droplet mist now have a substantially larger surface area than the fuel jets before they hit the atomizing sieve 50a, which in turn is an indicator of good atomization. It can also be said that countless "jet spikes" consisting of the finest droplets are formed by the mesh shape downstream of the atomizing sieve 50a. This mode of operation just described also draws all of the following listed embodiments.

In the first exemplary embodiment of the atomizing sieve 50a according to the invention shown in FIG. 1 and its arrangement on the injection valve, the atomizing sieve 50a is concavely shaped in the form of a shell or a cup in the direction of flow of the fuel. This concave bulge 51 of the atomizing sieve 50a ensures that part of the fuel can converge in the direction of a deepest region 56 of the bulging atomizing sieve 50a. The fuel collected in this middle deepest area 56 represents a comparatively static amount of liquid for a short time, to which the armature 11 or the valve needle 5 and the associated opening of the valve body 5 are then drawn

Injector emerging from the spray openings 25 of the spray plate 21 hits new fuel. Thus, while fuel is collected in the central region 56 of the bowl-shaped atomizing sieve 50a by the bulge 51, the atomizing sieve 50a is only wetted continuously in the regions facing the bowl edge or the clamping ring 52. A particularly high atomization quality is thus achieved by the processing directly on the mesh of the atomizing sieve 50a and by the fuel impinging on the amount of liquid at rest, through which the processing takes place in this central region 56.

A minimum distance between the spray orifice plate 21 and the atomizing sieve 50a in the direction of the longitudinal valve axis 2 is particularly important for the quality of the preparation or atomization of the fuel. If this minimum distance is undershot, it can happen that between the spray orifice plate 21 and the atomizing sieve 50a formed volume with a too large Amount of fuel is filled and atomization no longer occurs or only to a limited extent. In the first exemplary embodiment, the atomizing sieve 50a is therefore arranged in such a way that it is clamped between the protective cap 40 and the valve seat carrier 1 only downstream of the valve seat carrier 1. In addition to the factor of the minimum distance between the spray orifice plate 21 and the atomizing sieve 50a, the mesh size of the atomizing sieve 50a also plays a decisive role, which decisively determines the spraying quantity per unit of time. The mesh size ultimately represents the size of each hole in the atomizing sieve 50a. Mesh sizes from approximately 0.1 mm are useful; however, the best atomization results are achieved at> = 0.2 mm mesh size.

In the arrangement according to FIG. 1, in which the atomizing sieve 50a is clamped with its clamping ring 52 between the valve seat support 1 and the protective cap 40, a cap end 58 of the protective cap 40 forms the downstream end of the entire injection valve. The

Atomizing sieve 50a is not bulged out so far that it protrudes downstream from the injection valve. Consequently, the atomizing sieve 50a cannot be destroyed by external mechanical influences on the injection valve. Instead, the atomizing sieve 50a itself forms a protective shield for the spraying orifice disk 21. The atomizing sieve 50a downstream of the spraying orifice disk 21 in fact considerably reduces the risk of icing, so-called plugging and lead sulfate deposits on the spraying orifice disk 21, since this keeps the suction pipe atmosphere away from the spraying orifices 25 becomes. These positive effects, which can be achieved in addition to optimal atomization, have already been discussed in detail. In the further exemplary embodiments of the following figures, the parts that remain the same or have the same effect as the exemplary embodiment shown in FIG. 1 are identified by the same reference numerals. Although the atomizing sieves 50 are additionally identified by letters, all further atomizing sieves 50 are distinguished by the mode of operation already described in the first exemplary embodiment. The different labeling is only intended to indicate various constructive training options.

The second exemplary embodiment shown in FIG. 2 differs mainly from the exemplary embodiment shown in FIG. 1 by the shape of the protective cap 40 and the attachment of the atomizing sieve 50b to the injection valve. The atomizing sieve 50b is also concave in the shape of a bowl in the flow direction and z. B. made of a stainless metal. The metallic fabric, for example, which is angled like a plate edge in its outer radial circumferential region 60, is poured into the protective cap 40 with this circumferential region 60. When the peripheral region 60 of the atomizing sieve 50b is poured into the protective cap 40, plastic residues naturally also enter the mesh of the atomizing sieve 50b immediately outside the peripheral region 60, which is indicated by an uneven plastic edge 61 in the fabric of the atomizing sieve 50b.

The atomizing sieve 50b is similar to that

Atomizing sieve 50a is recessed into the protective cap 40, ie the cap end 58 of the protective cap 40 delimits the injection valve downstream, while the deepest region 56 of the atomizing sieve 50b lies further upstream. This spatial arrangement offers adequate protection against mechanical damage. The protective cap 40 is designed as a protective crown. Averted from the valve closing body 7, for example, six protective tines 62 form the downstream end of the injection valve, similar to a crown turned upside down. The number of protective tines 62 can be made variable, that is, for. B. with two, four or six protective tines 62 on the protective cap 40th

The protective cap 40 in the form of a protective crown has advantages in the drip behavior of the injection valve over a closed, that is to say all-round protective ring. The fuel swirls downstream of the atomizing sieve 50b are weaker, as a result of which less fuel is deposited as a wall film on a protective cap inner wall 63. The slightly wetted protective cap 40 significantly reduces the risk of drops forming. In principle, however, it is of course also possible to pour the atomizing sieve 50b into a protective cap 40, which has only a one-piece, circumferential protective ring.

The atomizing sieve 50b, which in turn is concavely curved in the direction of flow, ensures that the fuel flows into the sieve center, that is to say into the central deepest region 56, and collects there briefly. In this central region 56, the fuel is best processed into very fine droplets with a large surface area. A convex curvature of the atomizing sieve 50 would result in a considerable wall film of fuel being formed on the inner wall 63 of the protective cap 40, since the fuel would flow onto the protective cap 40 radially outwards.

In accordance with the desired characteristics of the processed fuel, the atomizing sieve 50b can Mesh size and its radius of curvature can be varied. The production costs of the atomizing sieves 50 are comparatively low, so that different embodiments can also be produced without great effort. It should also be noted in the case of the exemplary embodiment in FIG. 2 that a minimum distance between the spray orifice plate 21 and atomizing sieve 50b is maintained, as a result of which a sufficiently large volume is created which cannot be completely filled with fuel when sprayed off. Falling below the minimum distance would significantly reduce the quality of the atomization.

FIG. 3 shows a third exemplary embodiment, in which the atomizing sieve 50c in the protective cap 40 downstream of the spray orifice plate 21

Double shell is poured. In this case, the atomizing sieve 50c has two bulges 51 which are concave in the direction of flow of the fuel, the bulges 51 not necessarily having to have a constant radius. As shown in FIG. 3, the cup-shaped bulges 51 can also be flat in their deepest areas 56. The embodiments of the bulges 51 of the atomizing sieve 50c are dependent on the tools for deforming the sieve and can accordingly be influenced by these tools.

Starting from a flat screen leaf, for example, the shaping process of the atomizing sieve 50 takes place, both to achieve a single bulge 51, as with the atomizing sieves 50a and 50b, and with several desired bulges 51, such as with the atomizing sieve 50c and further examples below. The sieve sheet, which is flat in the initial state, is shaped, for example, by deep drawing or embossing with tool stamps in such a way that the desired bulges 51 arise. The decisive factor for the selection of a specific deep-drawing variant is the deformability of the screen fabric or the complexity and desired quality of the bulges 51 of the atomizing screen 50 to be formed.

The two bulges 51 of the atomizing sieve 50c are shaped in such a way that, in the case of a spray-hole disk 21 with four spray openings 25, the fuel from two spray openings 25 in each case hits a bulge 51 in the double shell of the atomizing sieve 50c. The fuel is thus atomized and processed in two jet halves on the atomizing screen 50c. The bulges 51 can be formed, for example, with a circular or elliptical flat deepest area 56 or with a continuous radius of curvature.

FIGS. 4 to 8 show schematic, not to scale, basic sketches of atomizing sieves 50 with one or more sieve bulges and their assignment to the individual spray openings 25 of a spray orifice plate 21 with four spray orifices 25. The spray openings 25 of the spray orifice plate 21 are projected as spray openings 25 ' shown on the bulges 51 of the atomizing sieves 50 to illustrate the spraying of the fuel onto the atomizing sieves 50.

The atomizing sieve 50b shown schematically in FIG. 4 corresponds to that of the second exemplary embodiment shown in FIG. The fuel of all four spray orifices 25 of the spraying orifice plate 21 thus strikes a single bulge 51 of the atomizing sieve 50b, collides with the atomizing sieve 50b, partly converges in the direction of the deepest region 56 and is optimally atomized. The atomizing sieve 50d in FIG. 5, on the other hand, has four bulges 51, so that the fuel is one each spray opening 25 in exactly one bulge 51 of the atomizing sieve 50d. It is thus possible to process the amount of fuel sprayed into quarters. Sieve webs 65 which arise between the bulges 51 and which spatially separate the bulges 51 extend, for example, axially in the region of the peripheral region 60 of the atomizing sieve 50d. In FIG. 3, an exemplary embodiment with the atomizing sieve 50c, on which two bulges 51 are provided and in each of which one half of the beam is aimed, has already been shown and described in the associated text. FIG. 6 again illustrates this fact schematically.

Arrangements are also conceivable in which the bulges 51 of the atomizing sieve 50e according to FIG. 7 are divided asymmetrically for special purposes. The deep-drawing tools must be selected in accordance with a desired asymmetrical beam distribution in order to precisely shape the atomizing sieve 50e. By using stamps of different sizes for deep drawing, bulges 51 of different sizes are also achieved. For example, as can be seen in FIG. 7, it is possible to create two bulges 51 which differ from one another, the fuel emerging from three spray openings 25 meeting in one bulge 51, while only one fuel jet from a spray opening 25 is directed into the second bulge 51 . The deep-drawing tools can be used in such a way that a) a screen web 65 remains between the two bulges 51 and thus separates them spatially, that b) the two bulges 51 touch and thus merge into one another if they are at the same axial depth, that c) touch both bulges 51 at one point, but do not have the same extent in the axial direction, or that d) both of them Partially overlap bulges 51.

In FIG. 8, the atomizing sieve 50f is shown schematically, which is characterized by a circular and an annular bulge 51. Seen radially from the outside, the atomizing sieve 50f is likewise delimited by the peripheral region 60, which is ultimately cast in the protective cap 40. Following inwards, the peripheral region 60 is followed by the circumferential annular bulge 51, which has corresponding annular ones

Thermoforming tools is easy to manufacture. The annular bulge 51 is followed by the likewise annular sieve web 65 towards the central region of the atomizing sieve 50f, which thus also limits the inner circular bulge 51 to the outside. The circular

Bulge 51 and annular bulge 51 may have different widths in the radial direction. Seen in the axial direction of the built-in atomizing sieve 50f, both bulges 51 have their deepest region 56, for example at the same height, while the sieve web 65 extends, for example, exactly to the height of the peripheral region 60. With this arrangement, different beam patterns can be controlled in a targeted manner. A variant of this design is such that the sieve web 65, as shown in dashed lines in Figure 8, is formed in the center of the atomizing sieve 50f and is surrounded by only an annular bulge 51, so that a cross section of the atomizing sieve 50f results corresponds to atomization sieve 50c shown in FIG. This results in a particularly favorable uniform fuel quantity distribution.

A further exemplary embodiment for the use of the atomizing sieve 50 according to the invention is shown in FIG. 9. The atomizing sieve 50 is in the form of the Atomizing sieve 50b, that is to say configured with a single bulge 51 which is concave in the direction of flow. The outer circumferential region 60 of the atomizing sieve 50b is in turn cast into the protective cap 40, specifically in an inwardly projecting cap region 66 which bears against the valve seat carrier 1 immediately downstream thereof. Directly adjacent to the circumferential inner cap region 66, four protective prongs 62 of the protective crown, for example, extend in the axial direction downstream

Protective cap 40. The four protective tines 62 are arranged, for example, on the circumference of the protective cap 40 in such a way that they are always at the same distance from one another, that is to say they are each 90 ° apart. This results in the possibility of attaching a so-called beam splitter in the form of a separating web 68a, for example having a circular cross section. The separating web 68a is mounted in such a way that it runs downstream of the deepest region 56 of the atomizing sieve 50b from a protective prong 62 to the exactly opposite protective prong 62, which is 180 ° away, transversely through the valve longitudinal axis 2 and symmetrically the spray chamber enclosed by the protective prongs 62 divides. The at least two spray openings 25 are also symmetrical to the separating web 68a, so that at least one fuel jet is directed to the right and at least one fuel jet to the left of the separating web 68a. The assembly of the separating web 68a on the protective tines 62 is very simple, for example by pressing in, pouring or the like. The separating web 68a has the function of generating, maintaining or reinforcing a desired double spray of the injection valve.

FIG. 10 shows a detail in the area of the atomizing sieve 50b from FIG. 9, the beam splitter being shown differs in shape and arrangement from the embodiment shown in Figure 9. This is because the beam splitter is designed upstream of the atomizing sieve 50b in the form of a separating cone 68b. The separating cone 68b is arranged in the deepest region 56 of the atomizing sieve 50b, the cone tip extending toward the spray hole disk 21. It is possible both to subsequently place the beam splitter, for example the separating cone 68b, on the atomizing sieve 50b which has already been produced and is cast in the protective cap 40, and also to be formed directly in the same process of casting in the atomizing sieve 50b. In addition to the conical beam splitter 68b, beam splitters with completely different cross-sectional shapes, for example as tetrahedra, can also be arranged upstream and / or downstream on the

Sieve surface 55 are used. The use of several cones is also conceivable. For modern ones

Internal combustion engines, to which demands for variable and asymmetrical jet profiles are placed, it is expedient to provide beam splitters, such as separating webs 68a and separating cones 68b, which run asymmetrically in the injection valve, i.e. are not symmetrical to the longitudinal axis 2 of the valve, and can even run axially inclined. These arrangements also depend, for example, on a desired inclination of the atomizing screen 50b in the injection valve with respect to the longitudinal axis 2 of the valve.

FIG. 11 shows an injection valve for injecting a fuel-gas mixture with an embodiment of the atomizing sieve 50 according to the invention. At its downstream end, the valve seat support 1 is therefore at least partially surrounded radially and axially by a stepped concentric gas-enclosing body 70. The gas containment body 70 made of a plastic includes, for example, the actual gas containment downstream end of the valve seat support 1 as well as a gas inlet channel, not shown, which serves to supply the gas into the gas enclosing body 70 and is, for example, formed in one piece with the gas enclosing body 70. The formation of the gas enclosing body 70 can be varied in accordance with the spatial conditions of a valve receptacle, not shown. In the axial region of the extension of the spray perforated disk 21, the gas encasing body 70 is formed with an axially extending tubular section 71. The axial section 71 surrounds the downstream end of the valve seat support 1 at a radial distance from the supply of the gas up to the fuel emerging from the spray openings 25 of the spray plate 21. The radial distance of the gas enclosing body 70 in section 71 has the result that an annular

Gas inlet channel 72 is formed between the valve seat support 1 and the gas enclosing body 70.

The axially extending section 71 has at its downstream end a radially outwardly facing circumferential shoulder 74 which arises from the fact that the outer circumference of the gas encasing body 70 is partially radially recessed to form an annular groove 75. The sealing ring 41 arranged in this annular groove 75 serves for sealing between the circumference of the injection valve with the gas encasing body 70 and a valve receptacle (not shown), for example the intake line of the internal combustion engine or a so-called fuel and / or gas distribution line.

A stepped insert part 78, for example made of plastic, has a radially extending section 79 at a plurality of circumferential points on a downstream end face 76 of the valve seat support 1. In order for the gas to flow into a metering cross section ensure, adjoin the axially extending gas inlet channel 72, for example, three to six radially extending flow channels 80, which arise between the radially extending section 79 of the insert part 78 and the downstream end face 76 of the valve seat support 1 after the installation of the insert part 78 or the gas encasing body 70 and the gas flows radially through them. The gas then flows, as indicated by the arrows in FIG. 11, axially upstream into an annular channel 82 between a concentric section 83 of the insert part 78 tapering upstream in the shape of a truncated cone and the wall of the longitudinal opening 3 in the valve seat carrier 1 until the flow on the spray-hole disk is deflected 21 in the radial direction.

The gas enclosing body 70 presses with an annular section 84 extending inwards from the annular groove 75 in the direction of the longitudinal valve axis 2 via a concentric and cup-shaped sleeve 86 inserted between the insert part 78 and the gas enclosing body 70, which sleeve is firmly connected to the valve seat carrier 1 and thus for fixing the Insert part 78 with its radial section 79 ensures against radial section 79 of insert part 78, so that the inflowing gas can only enter flow channels 80 via openings 87 in sleeve 86 and a downstream escape between gas-containing body 70 and insert part 78 is excluded. With the aid of the insert part 78 and the sleeve 86, which at least partially engages under the insert part 78, the gas is ultimately metered in for improved preparation of the fuel emerging from the spray openings 25 of the spray nozzle disc 21. In the insert part 78 there is, for example, a conical, downstream widening mixture spray opening 89 that runs centrally and concentrically to the valve longitudinal axis 2 brought in.

Due to the exact clamping of the insert part 78, an axial distance between the spray plate 21 and an upper spray plate 21 facing

The end face 90 of the insert part 78, which corresponds to the axial extent of a gas ring gap 91 formed thereby, is fixed. The axial dimension of the extent of the gas ring gap 91 forms the metering cross section for the gas flowing in from the ring channel 82, for example treatment air. The gas ring gap 91 serves to supply the gas to the fuel discharged through the spray openings 25 of the spray plate 21 and to meter the gas. The gas supplied through the gas inlet channel 72, the openings 87 of the sleeve 86, the flow channels 80 and the ring channel 82 flows through the narrow gas ring gap 91 to the mixture spray opening 89 and meets the fuel discharged through the four spray openings 25, for example. Due to the small axial extension of the

Gas ring gap 91 accelerates the supplied gas and atomizes the fuel particularly fine. For example, the suction air branched off by a bypass in front of a throttle valve in the intake manifold of the internal combustion engine, air conveyed by an additional blower, but also recirculated exhaust gas from the internal combustion engine or a mixture of air and exhaust gas can be used as gas.

The mixture spray opening 89 in the insert part 78 has such a large diameter that the upstream from the

Spray openings 25 of the spray orifice plate 21, fuel that meets the gas coming vertically from the gas ring gap 91 for better processing, can escape unhindered through the mixture spray opening 89 of the insert part 78. The fuel-gas mixture emerging from the mixture spray opening 89 of the insert part 78 strikes an atomizing sieve 50 g immediately downstream, which, for example, with its circumferential circumferential region 60 is cast or cast on a lower side 93 of the insert part 78. This ensures that the fuel already processed by the gas hits the atomizing sieve 50g completely and the processing quality is further increased. The diameter of the mixture spray opening 89 at the lower end of the insert part 78 is, for example, the same size as the largest diameter of the bulge 51 of the atomizing sieve 50g, which is located exactly in the plane of the peripheral region 60. The bowl-shaped atomizing sieve 50g is again concave in the direction of flow and projects in the axial direction in the interior of the gas enclosing body 70 with its deepest area 56, for example, up to the shoulder 74 of the gas enclosing body 70. However, the shoulder 74 forming the downstream end of the gas enclosing body 70 also lies in this exemplary embodiment with its shoulder end 94, similar to the cap end 58 of the previous exemplary embodiments, further downstream than the atomizing sieve 50g, so that protection against mechanical influences is ensured.

FIG. 12 shows a next exemplary embodiment of a gas enclosure with a downstream atomizing sieve 50h, which is only to be understood as a schematic diagram. As in the previous exemplary embodiments, the valve seat support 1 is at least partially radially and axially enclosed at its downstream end by the stepped concentric gas-enclosing body 70. The axial section 71 of the gas enclosing body 70 surrounds the downstream end of the valve seat carrier 1 at a radial distance from the supply of the gas, so that the annular one Gas inlet channel 72 is formed. A stepped insert part 78 'is arranged at least partially in the interior of the valve seat carrier 1 downstream of the spray orifice disk 21 and is clamped or welded onto the inner wall of the valve seat carrier 1, for example, in the longitudinal opening 3. In order to ensure that the gas flows in as far as the fuel emerging from the orifice plate 21, an axially extending, radially extending flow channel 80 adjoins the axially extending gas inlet channel 72, which flow channel 80 is located between the lower, radially extending section 79 of the insert part 78 ′ and the downstream end face 76 of the valve seat carrier 1 after the installation of the insert part 78 'or the gas-enclosing body 70 is formed and the gas flows radially through it. The gas then flows, as shown by the arrows in FIG. 12, axially upstream in, for example, four intermediate channels 82 'between a concentric axial insert section 95 of the insert part 78' and the wall of the longitudinal opening 3 in the valve seat carrier 1 up to an annular space 96 which between of the spray perforated disk 21, the frustoconical section 83 of the insert part 78 'and the axial insert section 95 is formed. Outside of the four intermediate channels 82 ', the insert part 78' lies with its axial insert section 95 against the wall of the longitudinal opening 3, for example by means of clamping.

The gas encircling body 70 presses with the ring section 84 against the insert part 78 ', which in turn presses with its upper end face facing the spray hole disk 21 against the spray hole plate 21, so that the insert part 78' has an additional fixation in addition to the securing of the position on the wall of the longitudinal opening 3. This also ensures that the gas coming from the gas inlet channel 72 only enters the space 96 via the flow channel 80. In itself For example, four obliquely radially extending feed channels 98 for the gas are arranged at the same distance from one another, that is to say after 90 ° in each case, in the shape of a truncated cone tapering. These feed channels 98 connect the annular space 96 to the conically shaped mixture injection opening 89 which extends in the center and concentrically to the valve longitudinal axis 2 in the insert part 78 '. The axial section of the radial section 79 of the insert part 78' has a smaller outside diameter Insert part 78 ″ is introduced into a recess 99 provided at the downstream end of insert part 78 ′, for example by latching or clamping. The atomizing sieve 50h can now be clamped in the recess 99 between the insert part 78 'and the insert part 78''.

The insert part 78 ″ likewise has, in the center and concentrically with the valve longitudinal axis 2, an opening 100 which continues the conicity of the mixture spray opening 89 and in which the atomizing sieve 50h with its bulge 51 is located. Consequently, only the peripheral region 60 of the atomizing sieve 50h is clamped between the two insert parts 78 'and 78' '.

The supply channels 98 serve to supply the gas to the fuel dispensed through the at least one, for example four, spray openings 25 of the spray plate 21 and to meter the gas. The gas supplied is accelerated in the feed channels 98 and strikes the fuel in the mixture spray opening 89. The feed channels 98 are aligned in such a way that their imaginary extensions meet in the center of the atomizing sieve 50 h, that is to say in the deepest region 56. On the 56 collecting in the deepest area Fuel thus impinges on the fuel emerging from the spray openings 25, and moreover the gas flows precisely into this impact region. The fuel is therefore atomized particularly finely. The fuel jets emerging from the spray openings 25 can be directed both directly into the center of the atomizing screen 50h as well as parallel fuel jets at areas outside the deepest area 56 or as divergent fuel jets at edge areas of the bulge 51 of the atomizing screen 50h. The supplied gas does not necessarily have to flow towards the center of the atomizing sieve 50h, but can also be directed towards other areas of the bulge 51, for example towards the impact areas of the fuel on the atomizing sieve 50h. The atomizing sieve 50h is, for example, with its

Curvature 51 is formed so that it does not protrude from the insert parts 78 'and 78' 'downstream. The construction with two insert parts 78 'and 78' 'has the advantage that the atomizing sieves 50, which differ for example in the shape of the bulge or the mesh size, can be exchanged in a very short time.

Another exemplary embodiment, which is shown in FIG. 13, is characterized by a gas supply downstream of the atomizing sieve 50i.

Similar to the exemplary embodiment shown in FIG. 2, the protective cap 40 is also provided here, which forms the downstream end of the injection valve. The protective cap 40 is also attached, for example, via a snap-in connection on the valve seat support 1, which is effective when the protective cap 40 with its circumferential inner cap region 66, in which the atomizing sieve 50i is also cast with its peripheral region 60, on the downstream end face 76 of the valve seat carrier 1 abuts. That in the protective cap 40 cast-in atomizing sieve 50i is also concavely curved in the shape of a bowl in the direction of flow and is made, for example, of a rustproof metal.

The atomizing sieve 50i is embedded in the protective cap 40 with a retardation dimension, i.e. the cap end 58 of the protective cap 40 delimits the injection valve downstream, while the deepest region 56 of the atomizing sieve 50i lies further upstream. The protective cap 40 is also designed in the form of a protective crown, which has, for example, four axially extending protective tines 62. In the case of a symmetrical arrangement of the protective tines 62, they are each 90 ° apart. The protective crown in turn offers the advantage of an improved drip behavior of the injection valve.

The protective cap 40 in the exemplary embodiment shown in FIG. 13 no longer forms a radial wall of the annular groove 75 for receiving the sealing ring 41, but rather partially delimits the annular gas inlet channel 72 for supplying the gas. At its downstream end, the valve seat support 1 and the protective cap 40 are at least partially enclosed radially and axially by the stepped concentric gas-enclosing body 70. In the axial area of the extension

The perforated gas body 70 is formed with the axially extending tubular section 71. The axial section 71 surrounds an annular cap end part 102, with which the locking on the valve seat support 1 takes place and which is exactly opposite the protective prongs 62 in the axial direction, with a radial distance from the supply of the gas to the fuel atomized on the atomizing sieve 50i. The radial distance of the gas encasing body 70 in the section 71 from the protective cap 40 has the result that the annular gas inlet channel 72 is formed. The axially extending section 71 has at its downstream end the radially outwardly pointing shoulder 74, which arises from the fact that the outer circumference of the gas encasing body 70 is partially recessed radially to form the annular groove 75 for the sealing ring 41, namely in an axial extent exactly where the gas inlet channel 72 extends within the gas containment body 70. The gas enclosing body 70 and the protective cap 40 are firmly and tightly connected to one another, for example by welding or gluing in the region of the shoulder 74. This ensures that no gas escapes between the gas enclosure body 70 and the protective cap 40 in the direction of the intake line of the internal combustion engine.

Between the cap end part 102 or the cap area 66 with the cast-in peripheral area 60 of the atomizing sieve 50i and the protective tines 62 of the protective cap 40, for example, four obliquely radially extending supply channels 98 'for the gas are provided, which start at the downstream end of the gas inlet channel 72, to the atomizing screen 50i are directed towards and end on the protective cap inner wall 63 on the side of the atomizing screen 50i facing away from the spray orifice plate 21. The feed channels 98 'formed, for example, at a distance of 90 ° from one another are oriented such that their imaginary extensions, preferably those of the center lines of the feed channels 98', meet approximately in the center of the atomizing sieve 50i, that is to say in the deepest region 56 of the atomizing sieve 50i. Another possibility of aligning the feed channels 98 ′ is that the imaginary extensions meet the atomizing sieve 50i exactly at the points at which the individual fuel jets coming from the spray openings 25 of the spray plate 21 hit the inner sieve surface 55 the bulge 51 of the atomizing sieve 50i, which for example equates to a tangential contact. The gas flowing through the gas inlet duct 72 is accelerated in the feed ducts 98 'and then at least partially hits the outer sieve surface of the domed one

Atomizing sieve 50i. The gas is swirled on impact on the atomizing sieve 50i, on the one hand partially passes through to the inner sieve surface 55 and on the other hand flows outside the atomizing sieve 50i in the direction of the deepest region 56 of the atomizing sieve 50i. The

Feed channels 98 'can also be oriented such that the gas only hits the fuel mist emerging from the atomizing sieve 50i downstream of the atomizing sieve 50i.

With this gas supply downstream of the atomizing sieve 50i, a further improvement in fuel atomization is achieved. In addition, this variant is particularly cost-effective since the feed channels 98 ′ can be introduced very easily into the protective cap 40 and a gas ring gap is completely dispensed with. Desired fuel jet angles are largely retained despite the gas enclosure, since the fuel is not fully encompassed by the gas emerging from the supply channels 98 '.

FIGS. 14, 15 and 16 are only schematic sketches, the possible variants of the course of the feed channels 98 ′ shown in FIG. 13 for the gas relative to the projected spray openings 25 ′ of FIG

Show spray plate 21. In the exemplary embodiment shown in FIG. 14, the feed channels 98 'are designed as two channel pairs which differ in their cross-sectional size, as a result of which a gas feed with different intensity is achieved, which in turn a targeted spray pattern control of the fuel enables. Each pair of channels is formed by two supply channels 98 'exactly opposite one another by 180 °, with all supply channels 98' running between two projected spraying openings 25 '. The channel pairs can differ not only in their cross-sectional size, but also in their cross-sectional shapes, which can be circular, square or oval, for example. The arrows indicate the directions of flow of the gas and the fuel. With the help of the asymmetrical

The gas quantity distribution can be generated, maintained or amplified very well in two-jet valves. The two pairs of ducts can also be replaced by supply ducts 98 'which are introduced asymmetrically in the protective cap 40 in the circumferential direction and which can also be variable in their inclination to the longitudinal axis 2 of the valve. A further exemplary embodiment is shown in FIG. 15, in which the feed channels 98 'are oriented in such a way that they have imaginary extensions on the projected spray openings 25' or on the

Hit the collision points of the fuel on the atomizing sieve 50i.

A conical, for example, resulting from the inclination of the spray openings 25 of the spray orifice plate 21

The fuel jet can be split up into two fuel jets by the gas supply channels 98 ', so that the single fuel jet existing directly on the atomizing sieve 50 is advantageously divided into two fuel jets, for example each fuel jet representing half the fuel quantity of the originally individual fuel jet. The arrows on the projected spray ports 25 'indicate that the fuel is split away from the feed channels 98'. A further exemplary embodiment of a fuel injection valve with an atomizing sieve arrangement according to the invention is shown in FIG. 17. There are in fact several for a further improvement of the atomization quality or an optimal spray pattern control

Atomizing sieves, here the atomizing sieves 50i and 50j connected in series. The atomizing sieves 50i and 50j can be formed, for example, at a constant distance from one another, that is to say largely parallel. The circumferential areas 60 are poured into the protective cap 40, for example, in one method step. Instead of pouring the peripheral areas 60 of the individual atomizing sieves 50i, 50j, the atomizing sieves 50i, 50j can be individually provided with clamping rings 52, e.g. shown in FIG. 1 and stacked one above the other or with the aid of insert parts 78, similar to the insert parts 78 ″ shown in FIG. 12, inserted one behind the other in the protective cap 40. For this purpose, the protective cap 40 can expediently be made in several parts. In all of the exemplary embodiments, the atomizing sieve 50 can be used together with the protective cap 40 as an exchangeable preparation attachment which can be placed on the most varied types of injection valves.

The peripheral region 60 of the atomizing sieve 50i can be provided upstream and the peripheral region 60 of the atomizing sieve 50j downstream of the feed channels 98 ', so that the gas supply takes place exactly between the two atomizing sieves 50i and 50j. Further exemplary embodiments, not shown, result from the variation of the fabric widths, the number of

Atomizing sieves 50 and the arrangement of the feed channels 98 'in relation to the atomizing sieves 50. The feed channels 98' can be designed such that the gas flows downstream of the last atomizing sieve 50 and / or upstream of the first atomizing sieve 50 and / or between the two.

FIGS. 18 and 19 illustrate, by way of example, possible types of braiding of the atomizing sieves 50. The atomizing sieve 50 shown schematically in FIG. 18 has square meshes, while the atomizing sieve 50 in FIG. 19 provides two-layer or multilayer, interlaced fabric patterns. From Figures 20 and 21 it is clear that the mesh size can be designed variable. Thus, in order to adjust the atomization quality in terms of area, the fabric of the screen leaf of the atomization screen 50 is compressed towards the center in FIG. 20, while in FIG. 21 the fabric of the atomization screen 50 becomes denser towards the screen outer zone. However, it must be ensured that the mesh size does not fall below 0.1 mm, since otherwise too much fuel collects in the at least one bulge 51 of the atomizing sieve 50, which in turn leads to a deterioration in the

Atomization quality occurs. The best atomization results are achieved at> = 0.2 mm mesh size.

FIG. 22 shows an atomizing sieve 50 in the form of a perforated body which has small holes or openings over the entire surface and which have the same or different cross-sectional sizes. The atomizing sieve 50 shown in FIG. 23 has only longitudinal meshes which are limited at their edges only by the circumference of the atomizing sieve 50. This design is characterized by very tight wires z. B. stainless steel. The advantages of these special sieve shapes lie in addition to the very good atomization in the generation of completely new spray patterns. The atomizing sieves 50 can also be made from a semiconductor material, for example as Silicon wafers into which meshes or holes are etched according to FIGS. 18 to 23.

In addition to variations in the types of braiding and mesh sizes, there are other design options for the screen mesh or

Sieve leaves that are not recognizable from the figures. For example, fabric material with a circular, oval or square cross section can be used depending on the requirements. Particularly suitable as fabric material are stainless metal or Teflon, which is hydrophobic and thus prevents icing at temperatures down to -40 ° C, or PTC materials, i.e. materials with positive resistance-temperature coefficients, the resistance of which increases when heated. Bimetal screens have the advantage that the geometry of the atomizing screen, e.g. the shape of the bulge can be changed at different operating temperatures in the desired manner for the operating point-dependent beam angle variation.

Not shown in the figures are atomizing sieves which are not installed at right angles to the longitudinal axis 2 of the valve in the injection valve, that is to say have an inclined position, in order to generate asymmetrical spray patterns or to be able to optimally inject them into curved intake pipes of internal combustion engines. In order to achieve an optimal atomization quality of the fuel, the atomization sieves 50 have at least one concave bulge 51 when viewed in the direction of flow of the fuel. But especially with regard to the prevention of icing, so-called plugging and lead sulfate deposits on the spray nozzle 21 and on other components inside of the injection valve it may be expedient to use largely flat, pyramid-shaped atomizing sieves, which are also convex in the direction of flow. In FIG. 24 and in the subsequent figures, valves in the form of injection valves for fuel injection systems of mixed-compression spark-ignition internal combustion engines with atomizing sieves 50 according to the invention are at least partially shown as further exemplary embodiments, which are in the form of training, particularly in the areas of valve needle 5, of the valve closing body 7 and the valve seat body 16 differ from the previously explained and particularly shown in FIGS. 1 to 17, which, however, in no way give an indication of an exclusive use of the various atomizing screens 50 according to the invention in the valve types shown in each case. All of the mentioned and shown designs of the atomizing sieves 50 can therefore be used or attached to a wide variety of injection valves. The injection valve partially shown in FIG. 24 is already known per se and will therefore not be explained in more detail.

All of the exemplary embodiments shown below in FIG. 23 are particularly distinguished by the fact that a clear spatial separation of metering and preparation of the fuel is provided, which is achieved constructively with an extension element designated as atomizer attachment 105. The atomizer attachment 105 consists largely of a sleeve-shaped, elongated spacer 106 and the z. B. concavely curved atomizing sieve 50 at its downstream end, the spray orifice plate 21 with the at least one spray opening 25. The aim is to use the atomizer attachment 105 when the injection valve is in a fixed installation position to atomize the fuel in the ideal position in the air flow of the intake manifold Lay the internal combustion engine so that a wall film formation of the fuel in the intake manifold or manifold is reduced or prevented, as a result of which a significant reduction in the exhaust gas emission, in particular the proportion of HC, is achieved.

As part of a valve housing, the injection valve has a nozzle body 108 which extends at the downstream end, the downstream end of the nozzle body 108 representing the valve seat body 16. The stepped guide opening 15 is formed in the nozzle body 108, which extends concentrically to the longitudinal valve axis 2 and in which the valve needle 5 is arranged together with the valve closing body 7. The guide opening 15 of the nozzle body 108 has that on its

The end facing the atomizer attachment 105 has the fixed valve seat surface 29, which tapers in the shape of a truncated cone in the direction of the fuel flow, which together with the valve closing body 7, which also tapers in the shape of a truncated cone, forms a seat valve. At that

The spray orifice plate 21 bears against the atomizer attachment 105 facing the lower end face 17 of the nozzle body 108 and is fixedly connected to the nozzle body 108, for example, by means of a weld seam produced by means of laser welding. The spray plate 21 has z. B. a spray opening 25 through which the fuel flowing past the valve seat surface 29 when the valve closing body 7 is lifted off is sprayed into the atomizer attachment 105.

The sleeve-shaped spacer 106 is, for example, stepped, so that it surrounds the end of the nozzle body 108 designated as valve seat body 16 in the axial direction, in part directly and z. B. also to a small extent by a radially extending shoulder 109 on the Spray plate 21 is present. The shoulder 109 that reduces the cross section of the spacer body 106 results in a diameter of the spacer body 106 downstream of the spray hole disk 21 that is smaller than the outer diameter of the valve seat body 16. Starting from the shoulder 109, the spacer body 106 extends into the suction pipe (not shown), that is to say in the downstream direction, for example with a constant diameter. At the end of the spacer 106 facing away from the atomizing sieve 50, the spacer 106 is shaped such that it extends radially and thereby forms an annular groove in which the sealing ring 41 used for sealing against the suction tube is accommodated. Suitable attachment options for the spacer body 106 on the nozzle body 108 are, for. B. releasable locking, snap or clip connections, for which 108 grooves or ridges are provided on the nozzle body.

In order to prevent disruptive wetting of the inner wall 110 of the spacer body 106, the injection valve must spray off a fuel jet which is narrow in radial expansion and has the smallest possible opening angle, that is to say a so-called cord jet. With a spray plate 21 having a central spray opening 25 and the valve type shown in FIG

Cord rays can be generated, for example. Downstream of the spray plate 21, but in the upper part of the spacer 106 facing it, openings 111 are provided which, for. B. are arranged symmetrically on the circumference of the spacer 106. The air jets entering through the openings 111 are directed so that they do not aim at the atomizing sieve 50. In particular, the openings 111 are closer to the spray opening 25 than to the atomizing sieve 50. The two to eight, for example, as elongated holes, slots or circular bores formed openings 111 in the spacer 106 subsequently allow an air flow parallel to the fuel jet in the interior of the spacer 106. Because of the fuel jet emerging from the spray opening 25, intake manifold air is sucked in through the openings 111 according to the principle of the water jet pump. As a result, the vacuum which otherwise arises in the spacer body 106 downstream of the spray orifice plate 21 and thus also the backflow of air within the spacer body 106 from the atomizing sieve 50 to the injection valve or

Swirling of the fuel jet avoided. A backflow of air in the spacer 106 would lead to a very disadvantageous wetting of the inner wall 110 with fuel. The dripping of fuel with the injector switched off can now be done by this

Measure largely prevented. The exemplary embodiment shown in FIG. 24 is particularly advantageous since the atomizer attachment 105 with the spacer body 106 can be produced inexpensively due to its simple construction and can be mounted on the injection valve and nevertheless fulfills all the desired functions.

FIGS. 25, 26 and 27 show various exemplary embodiments of atomizing sieves 50 fastened to spacers 106, with FIG. 25 only one

24 shows an enlargement of the atomizing sieve area. In the case of spacers 106 made of plastic, the atomizing sieve 50 is expediently injected directly into the manufacturing process of the injection molding of the spacer 106. Depending on the materials used (eg also metal) for the spacer 106 and the atomizing sieve 50, other joining methods, such as welding, soldering or gluing, can also be used. As shown in FIGS. 25 to 27, there is, for example, a slight axial overlap of Spacer 106 and atomizing sieve 50, the spacer 106 partially surrounding the atomizing sieve 50.

FIGS. 26 and 27 show exemplary embodiments in which the spacer body 106 does not have a constant diameter, but rather has a positive or negative taper, that is to say it has an expansion or taper towards the atomizing sieve 50. These cross-sectional changes over the axial length of the spacer body 106 are possible at any time if an impact of the fuel on the inner wall 110 is avoided. The atomizing sieve 50 can be used to form the fuel spray to be sprayed in different geometrical configurations with differently shaped bulges 51, three of which are shown by way of example in FIGS. 25 to 27. According to the geometry of the spacer 106, the atomizing sieve 50 has z. B. a fairly tapered bulge 51 (Figure 26) or two bulges 51, which are separated by a central inner sieve web 65 (Figure 27). The latter variant is particularly suitable for spraying onto two intake valves of the internal combustion engine. In addition, according to the exemplary embodiment shown in FIG. 27, the bulge 51 can be designed in a ring shape, which completely surrounds the inner sieve web 65.

The spatial separation of metering and preparation is therefore essential in these exemplary embodiments. The metering takes place through the spraying orifice plate 21, the preparation by means of the atomizing sieve 50. The fuel leaves the spraying orifice plate 21 as a line jet at high speed and becomes typical at Distances of 5 - 50 mm to the atomizing sieve 50 are not significantly braked or deflected, so that the good preparation of the fuel by the atomizing sieve 50 already described is retained. Thanks to the spacer body lengths, which can be adjusted within wide limits, the ideal preparation position can be found for the same injection valve types for every internal combustion engine and each intake manifold. The consumption and emission-increasing cold start and acceleration enrichment of fuel can be greatly reduced with the same driving quality, since the wall film formation in the intake manifold is greatly reduced or even prevented due to the atomizer attachment 105.

FIG. 28 shows a further exemplary embodiment of an injection valve which corresponds to the injection valve shown in FIG. 24 in terms of its structure and technical principle and which also has an atomizer attachment 105, by means of which the atomizing sieve 50 according to the invention, with a is formed a clear spatial distance from the metering point. The exemplary embodiment shown represents in simplified form an experimental set-up, which is primarily intended to explain the technical principle and can also be designed in a structurally different manner from this arrangement.

The atomizer attachment 105 is used in this

Embodiment not only formed by the spacer 106 and the atomizing sieve 50, but also by a radially surrounding the valve seat body 16

Gas introduction element 113, which extends in the axial direction both upstream and downstream of the spray plate 21. The gas introduction element 113 is particularly characterized in that an annular gas supply from the at least one spray opening 25 escaping fuel in the spacer 106 is ensured. In the exemplary embodiment shown in FIG. 28, this gas supply looks such that outside air, which may be heated by waste heat from the internal combustion engine or an active heater, or exhaust gas flows into an upper annular gas distributor 116 via a gas connection 115, from there via an axially extending narrow one Flow channel 117 parallel to the longitudinal axis 2 of the valve into a second lower, annular, z. B. gas distributor 118 lying downstream of the spray plate 21, from where the gas enters, for example, obliquely running radial bores 119 into the spacer 106 (gas introduction). The two gas distributors 116 and 118 are only optionally provided. In this version of the experimental setup, the gas introduction element 113 has two internal threads, into which the injection valve with an external thread provided on the nozzle body 108 is screwed from one side and the spacer 106 from the other side, so that the gas introduction element 113 also acts as a connecting element between the injection valve and the spacer 106 serves.

The fuel is sprayed into the spacer 106 as a cord jet (jet angle <= 10 °) through the metering injection valve. This sleeve-shaped

Spacer 106 is dimensioned (length, diameter) such that the inner wall 110 is not directly wetted by the fuel jet. From the lower gas distributor 118, gas is thus either into the radial bores 119 or through tubes or orifices (not shown)

Spacer 106 initiated that a defined and stable gas flow is created.

A part of the gas can also enter the part of the spacer body on the intake manifold side facing the atomizing sieve 50 106 e.g. B. by a double wall, not shown here, of the spacer 106 so that the gas acts in the form of a gas atomizing which improves the atomization of the fuel (reduction of the droplet size). The gas flow in the

Spacer 106 enclosed fuel jet is atomized on impact on the atomizing screen 50. The gas flowing through the atomizing sieve 50 takes any remaining fuel with it (blowing out the atomizing sieve 50) and thus leads to a significantly improved discharge and processing behavior, especially at low intake manifold pressures. By means of an appropriately designed gas supply, the fuel jet can be additionally shaped before and after the processing by the atomizing sieve 50 (e.g. elliptical jet pattern, asymmetrical quantity distribution).

For optimal guidance of the gas emerging from the radial bores 119 in the spacer body 106, a gas guide insert 120 can optionally be provided, which serves for the flow deflection and the axial outflow of the gas due to an axially extending sleeve 122. The axial sleeve 122 of the gas guide insert 120 goes at its upstream end z. B. in a radially extending edge region 123, which is at least partially by the

Spacer 106 is pressed against the spray orifice plate 21, which prevents the gas guide insert 120 from slipping. The length and diameter of the gas guide insert 120 are dimensioned such that, on the one hand, no wetting of the inner wall 110 by the fuel emerging from the orifice plate 21 can occur and, on the other hand, the gas flowing in through the radial bores 119 is guided. In contrast to the exemplary embodiments shown in FIGS. 24 to 27, the atomizing sieve 50 can be shown in FIG an outer recess 125 at the lower end of the spacer 106 by z. B. glued, welding or snapping attached to this or be cast.

With the gas introduction element 113 shown in FIG. 28, it is possible to arrange the atomizing sieve 50 at a distance of significantly more than 50 mm (for example up to 100 mm) from the spray hole disk 21 and still have the same positive effects as with the injection valve of the figure To reach 24. Due to the gas flow, the fuel jet is not slowed down or less. The higher kinetic energy thus results in better atomization. When using hot gas, e.g. B. exhaust gas, air heated by waste heat from the internal combustion engine or gas heated by an additional electrical heater, the atomizing screen 50, the wall 110 of the spacer 106 and the fuel jet are heated. The evaporation of the fuel that results in this leads to an additional improvement in the treatment.

All of the exemplary embodiments following FIG. 28 are variations, modifications or improvements to the injection valves with atomizer attachments 105 shown in FIGS. 24 to 28. The functional principles described with reference to FIGS. 24 to 28 are essentially retained. Therefore, a detailed description of the injection valves and the spacers 106 is omitted here. The separation of metering and preparation of the fuel, which is caused by the atomizer attachment 105, is a decisive feature

Spacer 106 and atomizing sieve 50 is reached by all other embodiments. The various arrangements can be provided both with and without gas introduction. In addition, beam-shaping elements such as B. beam splitter 68 with involved. In this way, particularly in the case of four-valve engines, the distribution of the fuel can be adapted to the given intake manifold geometry.

The atomizer attachment 105 of the one shown in FIG

Embodiment is particularly characterized in that the spacer 106 is double-walled. Between the inner and outer walls of the spacer 106 there are, for example, two semicircular, axially elongated spaces 127, which extend to the atomizing sieve 50 and, directly downstream of the atomizing sieve 50, cause gas to surround the fuel by escaping gas, so that the droplet size is further reduced and so an improved atomization is achieved. Similar to the separating web 68a in FIG. 9, in the interior of the spacer body 106 there is a cross-wise, z. B. arranged a circular cross-section having beam splitter 68 upstream of the deepest region 56 of the atomizing sieve 50. The beam splitter 68 with the fuel tearing function in various directions, which has already been described several times, can also have other cross sections, not shown. FIG. 30 is a sectional illustration along the line XXX-XXX in FIG. 29 and illustrates the course of the beam splitter 68, which is fastened, for example, in the areas 128 of the spacer 106 formed between the spaces 127. The jet shapes of the fuel can ultimately be influenced by varying the dimensions (arc length, width) of the intermediate spaces 127.

In addition to the gas enclosure on the atomizing sieve 50, a gas inlet is also provided, which corresponds to the already explained improvement in the discharge behavior of the Serves fuel. The atomizer attachment 105 is designed in such a way that the inner wall of the spacer body 106 does not reach directly to the spray orifice plate 21, but rather a defined inflow ring gap 130 between it and the

Spray plate 21 forms. From the lower gas distributor 118, the gas can flow both axially into the interstices 127 and largely radially into the inflow ring gap 130 directly downstream of the spray orifice plate 21. The gas flowing through the inflow gap 130 ultimately also represents a certain gas enclosure of the fuel, which, however, only acts within the sleeve-shaped spacer 106 and exists in addition to the gas enclosure on the atomizing sieve 50.

The exemplary embodiment in FIGS. 31 and 32 differs from the fact that, instead of the double-walled spacer 106 and the gaps 127 formed thereby for gas containment, an elongated gas tube 131, largely having the length of the spacer 106, is provided directly on the inner wall 110. Starting from the gas distributor 118, the gas is introduced again via the inflow gap 130 directly into the sleeve of the spacer 106, while the gas encapsulation on the atomizing sieve 50 is made possible by the fact that from the gas distributor 118 two partial tubes 131 ', which are inclined to the longitudinal axis 2 of the valve, are formed unite to the gas tube 131 which extends axially up to the atomizing sieve 50. FIG. 32 as a section along the line XXXII-XXXII in FIG. 31 illustrates the course of the gas tube 131 near the atomizing sieve 50. At the end facing away from the partial tubes 131 ', the gas tube 131 is U-shaped. It extends into the deepest area 56 of the bulge 51 and is arched on the opposite side to a small extent pointing axially in the direction of the spray orifice plate 21 upwards. This end region 132 of the gas tube 131 is closed and has an axial length which corresponds to the axial extent of a cutting-shaped, flat, transverse to the

Bulge 51 of the atomizing sieve 50 corresponds to the beam splitter 68. In its deepest area 134, the gas tube 131 has outflow openings 135 for the gas. The gas tube 131 is in some way embedded in the beam splitter 68 in the region of the bulge 51 of the atomizing sieve 50. The fuel, which is divided by the beam splitter 68 and processed, among other things, by the atomizing sieve 50, is hit immediately downstream of the atomizing sieve 50 by the gas emerging from the gas tube 131 and atomized particularly finely into the smallest droplets. The gas also has the effect of further dispersing the two-beam radiation specified by the beam splitter 68.

Figures 33 and 34 illustrate a slightly modified embodiment. Here, the gas tube 131 also extends axially along the inner wall 110, e.g. B. until the beginning of the atomizing sieve 50 and then z. B. bent at right angles across the spacer 106 to the opposite side of the spacer 106. The end portion 132 of the gas tube 131 is thus horizontal or perpendicular to the longitudinal axis 2 of the valve, directly in the form of a beam splitter 68. The otherwise z. B. formed with a circular cross-section gas tube 131 therefore has in its end region 132 a triangular cross-section, which enables a beam distribution. On the lower side facing away from the spray hole disk 21, the end region 132 is in turn designed such that gas can flow out downstream through outlet openings 135. In this case it serves the gas already in contact with the fuel upstream of the atomizing sieve 50 does more to improve the discharge behavior of the fuel than to reduce the droplet size of the fuel.

The exemplary embodiment shown in FIG. 35 of a valve with spacer 106 and atomizing sieve 50 largely corresponds to the valve shown in FIG. 29. This figure 35 is only intended to illustrate the variety of variants that is possible by adding or omitting individual small components on the atomizer attachment 105. Therefore, only the differences from FIG. 29 are mentioned in the following. The gas is introduced via the radial bores 119 as connections between the lower gas distributor 118 and the interior of the spacer 106. No inflow ring gap 130 is provided in the area of the spray orifice plate 21. B. by installing the gas guide insert 120 of the atomizer attachment 105 close to the spray plate 21. Gas also flows axially from the gas distributor 118 between the two walls of the spacer body 106 in the direction of the atomizing sieve 50. This arrangement can be implemented either with or without a beam splitter 68.

In the atomizer attachment 105 shown in FIG. 36, just as in FIG. 29, two different gas flows, running approximately over the length of the spacer 106, are provided. Starting in turn from the gas distributor 118, part of the gas flows via the inflow ring gap 130 into the interior of the spacer body 106 directly on the

Spray plate 21 and another part on the two spaces 127, for example, which are formed by the double wall. The gaps 127, however, already end upstream of the atomizing sieve 50. This is particularly possible because the Atomizing sieve 50 is attached to the outer wall of the spacer 106 this time. The gas flowing into the spacer 106 from the gaps 127 before the atomizing sieve 50 has a different speed than the gas flowing inside the spacer 106, so that turbulence occurs when they meet because of the different flow directions. This solution is particularly suitable for improving the atomization of the fuel if no beam splitting is desired.

With the known radial bores 119 in the wall of the spacer 106 and the gas guide insert 120, it is also ensured in the embodiment in FIG. 37 that over a large part of the

Spacer 106 no wetting of the inner wall 110 takes place. A venturi nozzle 137 is provided in the downstream end of the spacer 106 facing the atomizing sieve 50. The Venturi nozzle 137 has the task of ensuring a very good mixing of fuel and gas before atomization and preparation of the fuel on the atomizing screen 50. This fuel-gas mixture accelerated in the Venturi nozzle 137 increases the processing quality of the fuel. The one, for example, is conical or pyramidal

Beam splitter 68 in the bulge 51 of the atomizing sieve 50 can optionally be arranged.

FIG. 38 shows a very simple embodiment of the atomizer attachment 105. The essential features of this exemplary embodiment are summarized: no gas introduction, but only suction of suction pipe air according to the principle of the water jet pump through the openings 111 and thus pressure equalization with the surroundings and avoiding wall wetting in the spacer 106 ; Beam splitter 68 web-like, for example at the end of the spacer 106 facing the atomizing sieve 50, extending transversely through it.

In Figures 39, 40 and 41 are some conceivable

Variants of atomizing sieves 50 are shown which differ from the bowl-shaped atomizing sieves 50 which have been described up to now in connection with the atomizer attachments 105 and have a uniform mesh size. The one shown in FIG. 39

Atomizing sieve 50 is characterized by a bulge 51 which does not have a constant radius. The bulge 51 is now much flatter. The z. B. having a sharp cutting edge beam splitter 68 is directly in the atomizing sieve 50, z. B. incorporated in its deepest area 56. FIG. 40 shows an example of a two-part atomizing sieve 50, in which e.g. B. a different sieve material is used in the deepest area 56 than in the rest of the bulge 51. By injection molding the various sieve parts in one

Operation, the multi-part atomizing sieve 50 is very easy to manufacture. The top view of an atomizing sieve 50 with a partial change in the mesh size, the same sieve material being used throughout, for example, is shown in FIG. 41. The atomizing sieve 50 here has a central, web-like sieve region 139, which, for. B. extends through the entire bulge 51 in a narrow strip. This inner sieve region 139 is surrounded on both sides by outer sieve regions 140, so that the atomizing sieve 50 is formed from three segments. It is particularly advantageous to design the inner sieve region 139 to have a coarser mesh than the outer sieve regions 140. Simply by using different mesh sizes in the atomizing sieve 50 and one of them resulting different atomization behavior, a certain jet shaping of the fuel can already be achieved. In addition, the variation of the mesh size proves to be favorable if boiling residues of the fuel are to be retained on the atomizing sieve 50 in view of the plugging problem already mentioned. These deposits can e.g. B. are bound very well in the fine-meshed outer sieve regions 140, while the middle sieve region 139 remains free.

FIGS. 42 and 43 show two further special cases of a desired jet division of the fuel. For spraying onto, for example, two intake valves of the internal combustion engine, it makes sense to use two separate, bowl-shaped atomizing sieves 50 (FIG. 42) which are attached directly to the downstream end of the spacer body 106 and are separated from one another by the beam splitter 68. The beam splitter 68 emerges directly from the wall of the spacer 106 and thus also gives the required stability in the area of the atomizing sieves 50. In addition to the spacer 106 in the exemplary embodiment in FIG. 43, the spacer 106 extends mainly downstream of the atomizing sieve 50 firmly connected, sleeve-shaped beam splitting element 141 is arranged. The beam splitting element 141 again has at its downstream end the actual, e.g. B. cutting-shaped beam splitter 68, which thus has a clear distance from the atomizing sieve 50. The length of the beam splitting element 141 can be made variable in accordance with the installation conditions and the geometry of the intake manifold and can thus be optimally adapted. The jet splitter 68 connected downstream of the atomizing sieve 50 ensures that the fuel spray which has already been atomized and prepared is directed in different directions (for example in two directions Inlet valves) is sprayed. This arrangement can be combined with a gas inlet at any time.

The valve shown in FIG. 44 with the atomizer attachment 105 is particularly characterized by the Venturi nozzle 137 built into the spacer body 106, which is already known from FIG. 37. However, the Venturi nozzle 137 is now arranged such that intake pipe air drawn in according to the water jet pump principle flows in via the openings 111 directly at the narrowest point of the Venturi nozzle 137. A cylindrical nozzle insert body 143 containing the Venturi nozzle 137 has the same outer diameter as the diameter of the inner wall 110 of the spacer body 106. This nozzle insert body 143 is, for example, in the

Spacer 106 is pressed. According to the number of openings 111 z. B. the same number of transverse openings 144 are provided in the nozzle insert body 143, through which direct connections from the openings 111 to the narrowest cross section of the Venturi nozzle 137 are formed. The formation of the openings 111 in the spacer 106 in the axial extent of the narrowest cross section of the Venturi nozzle 137 advantageously enables the greatest possible suction effect on the gas.

Claims

claims

1. Atomizing sieve for use in fuel injection valves for fuel processing, with a sieve leaf, characterized in that the sieve leaf has a shape deviating from a flat leaf shape.

2. atomizing sieve according to claim 1, characterized in that the atomizing sieve (50) is formed bowl-shaped curved.

3. Atomizing sieve according to claim 2, characterized in that the atomizing sieve (50) has more than one bowl-shaped bulge (51).

4. Atomizing sieve according to claim 1, characterized in that the atomizing sieve (50) is made of stainless metal, plastic, Teflon, PTC material or silicon.

5. atomizing sieve according to claim 1, characterized in that the sieve sheet of the atomizing sieve (50) has a mesh size of> = 0.1 mm.

6. Atomizing sieve according to claim 1, characterized in that the atomizing sieve (50) is made in one or more layers.

7. atomizing sieve according to claim 5, characterized in that the mesh size of the sieve sheet of the atomizing sieve (50) is not constant.

8. Atomizing sieve according to claim 1, characterized in that the atomizing sieve (50) is made of bimetal.

9. atomizing sieve according to claim 1, characterized in that the atomizing sieve (50) is arranged at least partially on the circumference in a clamping ring (52).

10. Fuel injection valve for supplying an internal combustion engine with fuel or with one

Fuel-gas mixture, with a longitudinal valve axis, with a valve closing part which cooperates with a valve seat surface, with at least one spray opening and with an atomizing sieve arranged on the fuel injection valve downstream of the at least one spray opening, characterized in that the atomizing sieve (50) at least has a sieve leaf which has a shape deviating from a flat leaf shape.

11. Fuel injection valve according to claim 10, characterized in that the atomizing sieve (50) is arranged at least partially on the circumference in a clamping ring (52) which is fitted between a valve seat carrier (1) and a protective cap (40) on the valve seat carrier (1) of the fuel injector. is clamped.

12. Fuel injection valve according to claim 10, characterized in that the atomizing sieve (50) with a peripheral region (60) in one at the downstream end of the Fuel injection valve attached protective cap (40) is cast.

13. Fuel injection valve according to claim 11 or 12, characterized in that the protective cap (40) has the shape of a protective crown with protective tines (62) directed away from the fuel injection valve.

14. Fuel injection valve according to claim 13, characterized in that the protective tines (62) of the protective cap

(40) project further downstream than a deepest area (56) of the atomizing sieve (50).

15. Fuel injection valve according to claim 10, characterized in that the atomizing sieve (50) has at least one bulge (51).

16. Fuel injection valve according to claim 15, characterized in that the atomizing sieve (50) has at least two bulges (51) which are arranged symmetrically to the longitudinal axis of the valve (2).

17. Fuel injection valve according to claim 15, characterized in that the atomizing sieve (50) has at least two bulges (51) which are arranged asymmetrically to the longitudinal axis of the valve (2).

18. Fuel injection valve according to claim 15, characterized in that the atomizing sieve (50) has at least one bulge (51) which is annular.

19. Fuel injection valve according to claim 10, characterized in that on the atomizing sieve (50) on its upstream and / or downstream surface (55) a beam splitter (68) is integrated.

20. Fuel injection valve according to claim 10, characterized in that a beam splitter (68) runs downstream of the atomizing sieve (50).

21. Fuel injection valve according to claim 10, characterized in that a gas ring gap (91) is provided between the at least one spray opening (25) and the at least one atomizing sieve (50) and the fuel emerging from the at least one spray opening (25) with that from the Gas ring gap (91) emerging gas collides so that a fuel-gas mixture hits the atomizing sieve (50).

22. Fuel injection valve according to claim 10, characterized in that between the at least one spray opening (25) and the at least one atomizing sieve (50) in an in a valve seat carrier (1) projecting insert part (78 ') supply channels (98) are formed, via which a gas can be supplied and the fuel emerging from the at least one spray opening (25) collides with the gas emerging from the supply channels (98) so that a fuel-gas mixture hits the atomizing sieve (50).

23. Fuel injection valve according to claim 10, characterized in that supply channels (98 ') for a gas are arranged on the fuel injection valve such that they end on the side of the atomizing sieve (50) facing away from the at least one spray opening (25).

24. Fuel injection valve according to claim 23, characterized in that the feed channels (98 ') are aligned so that their imaginary extensions to a deepest Target area (56) of the atomizing sieve (50).

25. Fuel injection valve according to claim 23, characterized in that the feed channels (98 ') are aligned so that their imaginary extensions tangentially touch the surface of the atomizing sieve (50).

26. Fuel injection valve according to claim 10, characterized in that at least two atomizing screens (50) connected in series on

Fuel injector are attached.

27. Fuel injection valve according to claim 11 or 12, characterized in that the atomizing sieve (50) together with the protective cap (40) forms an interchangeable preparation attachment.

28. Fuel injection valve according to claim 10, characterized in that between the at least one spray opening (25) and the at least one

Atomizing sieve (50) a spacer (106) is arranged so that there is a clear spatial separation of metering in the region of the at least one spray opening (25) and processing in the region of the atomizing sieve (50).

29. Fuel injection valve according to claim 28, characterized in that the spacer body (106) together with the atomizing sieve (50) forms an atomizer attachment (105).

30. Fuel injection valve according to claim 28, characterized in that the atomizing sieve (50) is arranged at a distance of 5 to 100 mm from the at least one spray opening (25).

31. Fuel injection valve according to claim 28, characterized in that the spacer body (106) is sleeve-shaped and has openings (111) on its side facing the at least one spray opening (25) for sucking in a gas.

32. Fuel injection valve according to claim 28, characterized in that the spacer body (106) is double-walled at least over most of its circumference and spaces (127) are provided between the two walls through which a gas can flow.

33. Fuel injection valve according to claim 28, characterized in that in the spacer (106)

Beam splitter (68) is integrated.

34. Fuel injection valve according to claim 28, characterized in that in the spacer body (106) has a smaller cross section than the spacer body (106) having gas tube (131) largely axially, which only near the atomizing sieve (50) has outflow openings (135).

35. Fuel injection valve according to claim 28, characterized in that in the interior of the spacer body (106) a Venturi nozzle (137) is provided with a cross-sectional reduction compared to the spacer body (106).

36. Fuel injection valve according to claim 28, characterized in that a gas guide insert (120) is arranged in the interior of the spacer body (106) downstream of the at least one spray opening (25), which has at least one largely axially extending outflow surface for a gas.

37. Fuel injection valve according to claim 28, characterized in that a defined inflow ring gap (130) for inflowing a gas is formed downstream of the at least one spray opening (25) by the geometry of the spacer body (106).