DE102012021664A1 - Injector for reducing agent - Google Patents

Abstract

Injector (1) for reducing agent, in particular for exhaust gas aftertreatment, further in particular for a motor vehicle, wherein the injector (1) comprises: - an injector housing (10) with at least one inlet channel (36) for reducing agent, which enters a nozzle chamber (34) of the Injector (1) opens; - A nozzle arrangement (16) and a nozzle valve (30) formed by means of a valve member (26) and a valve seat (28), via which a flow path from the nozzle space (34) to the nozzle arrangement (16) can be selectively released for the discharge of reducing agent; - A valve actuation assembly (40) for the axial displacement of the valve member (26) in a valve actuation direction (A) for a selective opening of the flow path; wherein the injector (1) furthermore has a displacement element (20), the displacement element (20) being received in the injector housing (10) such that it is displaceable in the valve actuation direction (A) and urged in the valve closing direction (-A) by an elastic element (60) is that when the displacement element (20) is displaced, in particular in the course of freezing of the reducing agent, the nozzle space volume is varied.

Description

The present invention relates to an injector for reducing agent according to the preamble of claim 1, in particular for an exhaust gas aftertreatment.

Generic Reduktionsmittelinjektoren are intended to reductant, for example in the form of aqueous urea solution (HWL) to supply to an exhaust gas stream, i. e. to be used in the context of exhaust aftertreatment devices. By injected into the exhaust reducing agent pollutant emissions from internal combustion engines in a known per se environment can be gently reduced.

Problematic in connection with the use of reducing agents is regularly that they can freeze in the injector and damage it in the course of the associated increase in volume. In the prior art, therefore, means have been proposed to prevent such damage. The publication DE 10 2010 045 509 A1 uses a compensation element in the supply line to the injector, which is disadvantageous in terms of the additional space required. In addition, the document shows DE 10 2009 032 488 A1 a generic injector for reducing agent with a nozzle housing, which is partially resilient, in particular designed as a bellows. However, this results in a disadvantageously twistable and thus generating significant tolerances construction.

From the publication DE 10 2009 032 487 A1 Furthermore, an injector for reducing agent is known which makes use of a pressure compensation valve in a peripheral wall of the injector. The disadvantage here is that a potential source of error is created by this additional opening in the wall of the injector body.

Proceeding from this, the present invention has the object to provide an injector, which overcomes the disadvantages of the prior art, high functional reliability in a compact space and effective protection against damage during freezing of the reducing agent guaranteed.

This object is solved by the features of claim 1. Advantageous developments and embodiments are specified in the further claims.

According to the invention, an injector for reducing agent, in particular for a motor vehicle, is proposed. The injector is intended in particular for use with reducing agent in the form of urea-water solution (HWL), z. B. AdBlue ^® , ie for an exhaust aftertreatment.

The injector according to the invention comprises an injector housing with at least one inlet (channel) for reducing agent, which opens into a nozzle chamber of the injector, a nozzle assembly (with at least one injection hole) and a nozzle valve formed by a valve member and a valve seat, via which a flow path from the nozzle chamber to the nozzle assembly for dispensing reducing agent is selectively releasable. The valve member is preferably designed as a valve needle (nozzle needle) or valve piston, i. e. essentially rod-shaped or bar-shaped.

The injector further includes a valve actuation assembly for axially displacing the valve member in a valve actuation direction for selectively releasing the flow path, i. e. for a valve opening and closing. According to the invention, the injector is characterized by a displacement element or a displacement body, the displacement element being displaceable in the valve actuation direction and being urged by an elastic element in the valve closing direction in the injector housing such that upon displacement of the displacement element, in particular in the course of freezing of reducing agent, the nozzle chamber volume varies, in particular increases, with a freezing of reducing agent in the nozzle chamber is.

By the displacement element, which is preferably guided over its outer surface to an injector housing inner wall, in particular against this sealing, in a number of embodiments also against rotation, advantageously an increase in volume of the nozzle chamber is possible with a freezing of the reducing agent, d. H. by (axial) displacement of the displacement element, whereby damage to the injector due to icing can be effectively prevented. At the same time, a robust, reliable and low-tolerance reductant injector is provided.

For sealing against the inner wall of the injector housing preferably (ring) sealing elements are introduced into the lateral surface of the displacement element, in particular at a nozzle near end.

In the context of the present invention, in particular the valve actuating assembly is accommodated on the displacement element, furthermore preferably also the valve member. As a result, the injector can be made particularly space-saving, insofar as the displacement element simultaneously acts as a component carrier for a plurality of components of the injector. The valve member can preferably be taken in a guide on the displacement element guided on the displacement element.

A valve actuating assembly accommodated on the displacement element can in particular comprise an actuator, preferably with a solenoid or an (electric) magnet arrangement and an armature, which latter can be arranged in particular on the valve member. About the armature, the magnet assembly when energized with the valve member to lift it or to a valve opening magnetically cooperate (magnetaktuatorbetätigtes valve). In the preferred embodiment, an elastic return element of the valve actuating assembly (or actuator system) for the valve member is attached or received on the displacement element, in particular in the form of a helical compression spring (nozzle spring) which exerts a force in the closing direction on the valve member, ie. H. for a valve closing.

In the context of the present invention, it is further preferred that the displacement element is urged by means of the elastic element, in particular in the form of a helical compression spring, against a nozzle-side spacer element in the injector housing. The spacer element acting as a stop is preferably formed by a spacer or adjusting ring introduced into the injector housing at the end of the nozzle. By selecting a - suitably formed - in terms of its axial extent or height - trained spacer element advantageously the valve member enabled valve lift can be easily adjusted insofar as formed by the displacement element stroke stop for the valve member in its distance to the nozzle near end can be varied.

In a first preferred structural embodiment of the displacement element or the injector, the displacement element has a substantially H-shaped body in cross-section with in particular substantially cylindrical lateral surface. The H-shape, in which the legs extend axially, makes it possible to provide a first, nozzle-remote chamber and a second chamber closer to the nozzle for receiving the valve actuating assembly and sealing it in a simple manner.

The first chamber, which is remote from the nozzle, may be provided on the base body for receiving the magnet arrangement together with the armature cooperating therewith, while the second, chamber-near chamber serves to receive the elastic return element. In this embodiment, the valve member preferably extends from the first chamber into the second chamber, d. H. through the crosspiece of the H-profile, wherein the valve member connects the nozzle distant anchor with the nozzle-near closure head (rigid). The elastic return element may in this case be trapped between the closure head of the valve member and the displacement element.

For sealing on the valve member and the peripheral wall of the first chamber (opposite an armature and magnetic space in the first chamber) may be provided a diaphragm seal, which is guided radially from the valve member to the chamber wall, in particular between the nozzle distal end of the guide of the valve member and a Is arranged near the nozzle end portion of the armature. The membrane seal allows expansion upon ice formation (freezing of reductant entering the first chamber via the guide of the valve member) and thus "draining" of the magnet and armature space (in the first chamber). As a result, the magnet assembly and the armature is protected from the aggressive reducing agent.

In order to hold the magnet assembly in the first chamber, in particular advantageously inexpensive, and at the same time to perform the chamber in a media-tight manner at the end, a cover element, which also preferably carries the magnet arrangement, can be mounted at the nozzle-distal end of the base body.

The second chamber on the displacement element is preferably open towards the nozzle, wherein the second chamber also provides or forms a nozzle chamber volume. An inner side of the second chamber can also form a stroke stop for the valve member.

In particular, in order to control the expansion of the ice upon freezing of the reducing agent in the axial or longitudinal direction, it is provided to form the nozzle chamber by means of the displacement element, in particular the second chamber, such that an expansion of the ice in the opening direction of the nozzle valve is channeled. For this purpose, for example, the cross section of the second chamber from the nozzle near end to the crosspiece of the H-profile taper, for example, have a conical or frusto-conical cross-section.

In preferred embodiments of the reducing agent injector according to the invention according to the first embodiment described above, the injector further comprises at least one phase transition compensation element, by means of which a force in the opening direction is exerted on the valve member during a phase transition from liquid to solid on the same, in particular in the course of freezing, in particular, the flow path from the nozzle chamber to the nozzle arrangement is released. The phase transition compensation element is suitably operatively connected in particular with the valve member, z. B. via a pull rod. It is proposed that the phase transition compensating element contains a liquid or a filling medium whose phase transition from liquid to solid takes place when it freezes before the phase transition of the reducing agent used with the injector, ie first in time.

In particular, if the filling medium of the phase transition compensation element is selected such that the phase transition of the phase transition compensating element takes place at a first temperature and the phase transition of the reducing agent at a freezing at a second, compared to the first temperature lower temperature, wherein the solidification temperature difference between the first and second temperature is preferably in the range of 1 to 3 degrees Celsius, it can be ensured that the intended operating range of the injector with the proposed reducing agent is available almost unrestricted. As a filling medium can, for. As water can be selected, in particular z. For example, by selecting a suitable filling liquid, the freezing point can be set to -10 ° C, that is to say the freezing point. H. z. B. to a degree Celsius above the freezing point of HWL.

The phase transition compensating element may be provided as a diaphragm cell, e.g. B. as a single or double-acting, medium-filled diaphragm cell, and has the general task of lifting the valve member upon freezing of the injector from the valve seat, i. e. to open the nozzle valve. As a result, the nozzle chamber can be relieved of pressure advantageously, so that the still liquid reducing agent can drip out before freezing, i. e. can escape through the nozzle assembly. Thus, a pressure equalization valve provided separately on the injector in addition to the nozzle valve is advantageously dispensable.

Preferably, the phase transition compensating element (together with its active composite components) is arranged or attached to the displacement element, in particular at its nozzle-distal end, wherein it is in particular axially displaceable together with this. In this case, the phase transition compensating element can act on the valve member via an (axially displaceable) pull rod. The pull rod may be bolted or otherwise secured to the valve member.

The phase transition compensation element may further allow to pull the valve member in a freeze of the injector in a stop, z. B. against the sliding element, s. o., So that a seal of the nozzle chamber is ensured with respect to a guide for the valve member, d. H. in such a way that penetration of reducing reducing agent into cavities on the displacement element is largely avoided.

In particular, an injector, which further comprises a phase transition compensating element in addition to a displacement element as explained above according to the first embodiment, is capable of a multi-stage pressure relief of the nozzle chamber. In a first stage, z. B. the valve member can be raised via the phase transition compensation element, so that the nozzle valve opens, z. B. by 0.5 mm to 1 mm. Upon further freezing, the displacement element can subsequently provide additionally required compensation volume in the course of a displacement.

In second preferred embodiments of the injector, an armature space of the valve actuating assembly is formed on the displacement element, wherein the armature space is separated from an adjacent magnet space of the valve actuating assembly, in particular at the nozzle-distal end of the armature space, by means of a compensation element (to compensate for icing pressure), in particular, however, also sealed. It is provided that the armature space communicates with the nozzle chamber via an (axial) guide formed in the displacement element for the valve member.

In this embodiment of the injector is advantageously allows on the one hand "dry" the magnetic space and thus the magnet assembly received therein and thus to protect and on the other hand, allow in the armature space freezing reducing agent volume increase. In particular, in this case an advantageously simple assembly can be achieved. For example, the magnet assembly may be provided at the nozzle distal end of the armature space provided with the compensation element or sealed by means of a union element, e.g. B. a union nut on the main body of the displacement element are attached inexpensively.

Preferably, the compensation element comprises a membrane (seal), which is provided for the arrangement between the armature and the magnet space (first expansion element). The membrane seal or the compensating element may be an elastomeric seal, which is arranged at the nozzle-near end of the magnet arrangement. Preferred for their expansion, i. e. in the course of icing in the anchor space, a compensation space, in particular annular space, formed at the adjacent end of the magnet assembly, in which it can dive. Alternatively, a corresponding gap spacing may be provided between the compensation element or the membrane and the magnet arrangement, with the aim of making the membrane seal as thin as possible (disk-shaped).

Preferred embodiments of the injector or of the compensation element provide an expandable element in addition to the membrane (second expansion element). The expandable element may be formed by a (pleated) bellows which preferably forms a central portion of the compensation element, in particular extending axially away from the (radially extending) membrane seal (towards the nozzle-distal end of the injector). Like the diaphragm, the bellows can be made of elastomer (material), in particular advantageously increasing the compensation potential. The bellows can communicate with the anchor space via an open end.

Preferably, the elastically expandable element extends from the nozzle near end of the magnetic space between or in the magnet assembly, for. B. in an iron core and / or z. B. potting the same inside, in particular in a compensation room, z. B. an (opening) bore, preferably towards a nozzle remote end of the magnetic space. Thus, the expandable element can advantageously be accommodated or arranged in a space-saving manner within the magnet arrangement.

The elastically expandable element may in this case be spring-loaded in the direction of the nozzle arrangement, preferably in particular such that an expansion of the same is only made possible after exceeding a pressure threshold value at the armature space above an operating pressure of the injector. This avoids that the expandable element always performs a movement at applied injection pressure, i. e. extend its life. As the pressure threshold value, a pressure level corresponding to 1.5 to 2 times the injection pressure may be provided.

In general, the use of metal, in particular sheet metal sections, is provided for the compensation element in addition to the use of elastomer. For example, a support ring made of sheet metal can be vulcanized into an elastomer body, for. B. also be provided a sheet membrane with elastomeric coating.

In the second embodiment of the injector is further provided to form ventilation channels in the displacement element, in particular the base body, which allow a circulation of the reducing agent between the armature space and the nozzle chamber, i. e. each communicate with both the anchor and the nozzle space.

In particular, the ventilation channels are preferably designed such that upon opening of the nozzle valve, a pressure imbalance between the mouths thereof, in particular at the armature space is generated. This can be accomplished by having a ventilation duct, which communicates with the armature and the nozzle space, with a nozzle space orifice in the vicinity of the nozzle assembly is guided (high suction effect from the nozzle assembly when opening the nozzle valve), while another ventilation channel communicates with the armature and the nozzle space, with a corresponding nozzle space mouth of the nozzle assembly is relatively further away (low suction effect from the nozzle assembly).

The use of such ventilation channels, z. B. formed by means of at least two tubes, further allows advantageous that the injector can operate independently of position. When the injector freezes from the nozzle-distal end to the nozzle-near end, the forming ice can press a part of the reducing agent to be displaced through the ventilation channels into the nozzle chamber.

With increasing ice pressure, the displacement element can now allow by its displacement compensation.

A displacement element according to the second embodiment of the injector may have a main body whose shape allows both the guide on the inner surface of the injector and the formation of the armature space at a nozzle distal end of the same. Furthermore, the displacement element or its base body preferably comprises an axial guide, in particular bore, for receiving the nozzle needle and the nozzle spring or the return element. The return element can be trapped in the guide at a nozzle-distal end of the guide by means of a sleeve (pressed, screwed, or the like).

It is generally provided in the context of the present invention that the elastic element, in particular in the form of a helical compression spring, acts against a nozzle-distal end of the displacement element. In the first embodiments of the injector, the elastic element may on the one hand be supported against a housing element on the injector housing, i. H. on the other hand be urged against the nozzle remote end, on the other hand against a cover element on the displacement element.

In the second embodiments of the injector can be provided that the elastic element is supported on the one hand as against a housing element on the injector, on the one hand. H. at the nozzle-remote end, on the other hand against a closure element on the displacement element, for. B. on the magnet assembly or against the Verspannelement (union nut).

About the - so caught - elastic element is preferably a force on the Displacement element exerts in the valve closing direction, which is greater than a predetermined maximum operating pressure force on the displacement element in the valve opening direction, corresponding to a pressure level about 1.5 to 2 times higher than the injection pressure. This ensures that the displacement element is not moved inadvertently during an injector operation or at an applied operating pressure, that is, a shift can only take place when the injector freezes, accompanied by higher pressure levels than the operating pressure.

In the injector, in particular the second embodiment, it can be provided to flow reducing agent tangentially via an inlet channel to the nozzle (ring) chamber and to allow tangential discharge from the nozzle (ring) chamber via an outlet channel. A swirl flow generated in this way allows good cooling during operation by the fluid flowing through. Furthermore, it can preferably be provided to form an inlet channel (and an outlet channel) depending on the nozzle-near end of the injector. In this way, an injector can be supplied via a slot in a receiving plate together with other injectors, in particular without a lead or tubeless with reducing agent, in particular in series with multiple injectors.

Furthermore, it is generally provided to manufacture the base body of non-magnetic material, for. As aluminum or alloys thereof.

The injector can be used with an exhaust aftertreatment device, in particular in a motor vehicle, in particular a passenger car, a ship or a utility vehicle. An exhaust aftertreatment device may further comprise, in addition to the injector, a delivery pump which delivers reductant, in particular HWL, via a line to the injector inlet, preferably from a reducing agent tank of the exhaust aftertreatment device. Via an electrical control of the valve actuation assembly, in particular the magnet arrangement of the injector, the nozzle valve can be selectively actuated and reducing agent can be injected as needed into an exhaust tract, z. B. upstream of a catalyst.

Further features and advantages of the invention will become apparent from the following description of embodiments of the invention, with reference to the figures of the drawings, which show details essential to the invention, and from the claims. The individual features can be realized individually for themselves or for several in any combination in a variant of the invention.

Preferred embodiments of the invention are explained below with reference to the accompanying drawings. Show it:

1 exemplary and schematically a sectional view of an injector with a displacement element according to a first possible embodiment;

2 to 4 exemplary and schematically each a sectional view of embodiments of an injector according to the first embodiment and further each a phase transition compensation element;

4a by way of example, a lever element on the phase transition compensation element to form a functional composite;

4b exemplary and schematically the lever element of 4a in the plan view;

5 exemplary and schematically a sectional view of an injector with a displacement element according to a second embodiment of the injector;

6 to 10 exemplary and schematic each details of possible embodiments of an injector according to the second embodiment; and

11 an example and schematically an illustration of the flow through the nozzle chamber of an injector with tangential inflow / outflow.

In the following description and the drawings, the same reference numerals correspond to elements of the same or comparable function.

The 1 to 4 such as 5 show one injector each 1 for reducing agent for use with an exhaust aftertreatment device, especially in a motor vehicle. The reducing agent injector 1 has an injector housing 10 on which a substantially hollow cylindrical interior 12 defined, in 5 with a stepped profile. At a first end 14 of the housing 10 is a nozzle arrangement 16 of the injector 1 formed, via which the dispensing of reducing agent, in particular in the form of urea-water solution (HWL) is possible.

In the interior 12 of the injector 1 is a displaceable body or displacement element 20 arranged, which in an axial displacement direction A relative to the injector 10 is displaceable. Obvious is the sliding element 20 here on the inner surface 22 of the injector housing 10 by means of corresponding lateral surface cross section of its outer jacket 24 guided axially displaceable. On the sliding element 20 is a valve member 26 in an operating direction, which corresponds to the axial displacement direction A of the displacement element A, axially displaceably received. The valve member 26 works with one at the first end 14 formed valve seat 28 to form a nozzle valve 30 of the injector 1 together, ie via a closure head 32 ,

Via the nozzle valve 30 can the nozzle space 34 , which via a reducing agent inlet channel 36 of the injector 1 can be flowed on, be relieved when opening.

To the nozzle valve 30 by means of the valve member 26 to selectively open or close, ie a flow path from the nozzle chamber 34 to the nozzle assembly 16 to selectively release, the injector points 1 furthermore a valve actuating assembly 40 on, which in the context of the present invention advantageously space-saving on the sliding element 20 is included, ie the sliding element 20 is a component carrier for the valve actuation assembly (and valve member 26 ). The valve actuator assembly 40 includes a solenoid or a magnet arrangement 42 , an anchor 44 , which at the nozzle distal end of the valve member 26 is arranged and further a return spring 46 ,

A simple and space-saving recording of the valve actuator assembly 40 (and the valve member 26 ) is in the injector according to the 1 to 4 , ie according to the first embodiment, in particular achieved by the fact that the displacement element 20 by means of a basic body 50 is formed, which has a substantially H-shaped cross section, z. B. 1 , Due to the design with H-shaped cross section are on the body 50 a first 52 and a second 54 Chamber partitioned, which for arranging or receiving the components of the valve operating assembly 40 be available.

In the nozzle-distant first chamber 52 are next to the anchor 44 the magnetic package 42 received, ie on a cover element 56 the sliding element 20 , which end with the main body 50 is screwed. Through the lid element 56 is still a supply line 57 for energizing the magnet package 42 guided.

In the second chamber close to the nozzle 54 which is a nozzle chamber volume 34 represents, is the return spring or nozzle spring 46 added. Evidently, the second chamber 54 in the direction of the nozzle near the nozzle-distal end tapered cross section, which channels the expansion of the ice in the direction of displacement A in the event of icing of reducing agent to a displacement of the displacement element 20 along with a pressure relief of the nozzle chamber 34 reliable effect.

Continue in an axial bore or guide 58 from the first 52 in the second 54 Chamber extending the valve member 26 at the base body 50 led recorded. The valve member 26 has here at the nozzle distal end of the anchor 44 on, at the nozzle-near end a ring collar 59 , by means of which the return spring 46 in the second chamber 54 is caught. About the anchor 44 can the valve member 26 for opening the valve 30 when the magnet is energized 42 be raised magnetically, via the return spring 46 which the valve member 26 acted upon by a force in valve closing direction -A, be moved back for a valve closing.

The sliding element 20 is by means of an elastic element 60 in the form of a helical compression spring, which at the other end against a housing (screw) use 62 of the injector housing 10 , z. B. also a cover element 63 , is supported, against a spacer element 64 urged, which at the nozzle end 14 in the injector housing 10 is arranged. This exceeds that of the compression spring element 60 generated compressive force in valve closing direction -A, which on the sliding element 20 acts, the maximum intended operating pressure, which in the valve opening direction + A on the sliding element 20 can work. On the one hand, this ensures that the sliding element 20 during operation of the injector 1 is not moved unintentionally, while on the other hand ensures that an icing pressure exceeding the operating pressure advantageous to an intended displacement of the displacement element 20 leads (in opening direction + A). In addition, can via targeted selection of the spacer element 64 In a simple way, the stroke can be adjusted, which the valve member 26 is possible in operation. The allowed stroke is limited by a stop surface 65 in the second chamber 54 , against which a shoulder surface 66 on the valve member 26 can get to the plant.

For sealing on the valve member 26 and the chamber wall of the first chamber 52 opposite the anchor and magnet space, ie against the guide 58 entering reducing agent, the injector 1 furthermore a membrane seal 68 which extends radially around the valve member 26 to the peripheral wall of the first chamber 52 extends, sa 1 to 4 ,

In preferred embodiments of the injector according to the invention 1 according to the first embodiment, below with reference to 2 to 4b explained in more detail, the injector 1 Farther at least one phase transition compensation element 70 on, which in particular with the valve member 26 is operatively connected, and by means of which a self-day opening of the nozzle valve 30 during freezing or icing of the injector 1 and thus a discharge of the nozzle chamber 34 can be effected, in particular before / immediately before reducing agent in the injector 1 freezes. Relieving the nozzle space 34 via the phase transition compensation element 70 this can be advantageous regardless of a discharge of the nozzle chamber 34 via the sliding element 20 take place, ie in addition to or z. B. instead of such.

The phase transition compensation element 70 includes a filling medium 72 or a liquid which undergoes a phase transition from liquid to solid in the course of a freezing, wherein the liquid is selected such that its phase transition at a slightly higher temperature, ie present z. B. -10 ° C than those, z. B. -11 ° C, a corresponding phase transition of the reducing agent takes place. Such becomes the possible operating range of the injector 1 not unnecessarily restricted. As a liquid, for example, a salt-water solution or a water-antifreeze solution can be used, but woneben also a variety of other suitable solutions are conceivable.

In the following, in particular, the active compound of the phase transition compensation element 70 with the valve member 26 described: The end of the sliding element at the nozzle end 20 arranged phase transition compensation element 70 , s. 2 to 4 which is nozzle-facing on the lid 56 is arranged, is formed as a diaphragm box, which via a pull rod 74 connected to the valve member 26 is rigidly connected to the valve member 26 can work. This is on the drawbar 74 an attack surface 76 for the introduction of force on the part of the membrane 78 or the phase transition compensation element 70 provided, ie present by means of a countered annular disc 80 , A compression spring 82 acts as a pressure element to the continuous installation of the annular disc 80 at the diaphragm can 70 to ensure.

When the filling medium freezes 72 ie, in a phase transition from liquid to solid, the membrane bulges 78 due to the increase in volume of the filling medium 72 outward, ie in the direction + A, shown in dashed lines, and acts in this case against the attack surface 76 , The drawbar 74 thus experiences a force in the opening direction + A of the valve 30 , which via the axially displaceable pull rod 74 also on the valve member 26 acts and lifting it from the valve seat 28 leads. About the now open valve 30 Reducing agent can thus escape from icing and in this case the nozzle chamber 34 relieve.

The advantage here is that when lifting the valve member 26 via the phase transition compensation element 70 the valve member 26 also against the stop surface 65 is crowded, allowing the penetration of icing reducing agent into the lead 58 or the first chamber 52 is avoided. To pass through the phase transition compensation element 70 if necessary, or if necessary to be able to translate caused stroke, in particular to be able to increase, the active compound (phase transition compensation element / valve member) or the injector 1 in the context of the present invention also a lever or translation element or a lever mechanism 75 provide, for. B. a slotted sheet metal disc, which between the phase transition compensation element 70 and the attack surface 76 the drawbar 74 is arranged, s. 4a and 4b , The z. B. annular plate 75 can edge of the phase transition compensation element 70 be attached, z. B. by forming, with edge-mounted lever arms 77 the sheet metal disc 75 which is on the membrane 78 rest, with free ends at volume expansion of the phase transition compensation element 70 or curvature of the membrane 78 by providing a leverage (I2 / I1 corresponds to the gear ratio) against the attack surface 76 Act.

To also a flow of reducing agent through the inlet 36 at discharge of the nozzle chamber 34 To prevent the use of a retaining valve may be provided in a HWL inlet. To increase a capillary action on the nozzle assembly 16 can a suitable nozzle inner mold or a lubricious coating, for. As Teflon contribute.

The following will cursory on different ways to form the Injektoreinlasses 36 received. According to 1 and 2 can be provided, the reducing agent via an inlet channel 36 at the nozzle end 14 of the injector housing 10 in the nozzle chamber 34 to bring in, ie in the area of the (this broken through) spacer 64 , This represents an advantageous, inexpensive solution which can provide a retention valve to avoid secondary flows. According to three can be provided, the inlet (channel) 36 to form such that an automatic shut-off of the inlet during displacement of the displacement element 20 takes place, insofar as the lateral surface 24 the sliding element 20 in this case an inlet opening 84 in the injector housing 10 closes. A plurality of sealing elements 86 , which are in depressions on the mantle 24 taken as a ring seals performed, this prevents leakage of leakage at the adjacent lateral surfaces 22 and 24 , Furthermore, z. B. be provided, an inlet connection 88 with the sliding element 20 mitzuschieblich train, why in the injector housing wall 10 a corresponding recess 90 is formed, 4 ,

5 shows an injector 1 according to the second embodiment, wherein the displacement element 20 an approximately cupped body 50 with a nozzle-distant chamber 52 which, as in the first embodiment of the injector 1 - Made of non-magnetic material, in this case aluminum. By means of the chamber 52 becomes an anchor space 92 formed, in which the anchor 44 , which at the nozzle distal end of the valve member 26 is arranged, is included. The anchor room 92 communicates via the bore or guide 58 in which the valve member 26 is guided axially displaceable, with the nozzle chamber 34 at the nozzle-near end 14 of the cavity 12 , In the hole 58 is still the return spring 46 taken up, ie between one in the main body 50 pressed sleeve 94 and a shoulder surface 96 on the valve member 26 captured. At the base of the cup form becomes the basic body 50 over its outer surface 24 on the inner circumferential surface 22 of the injector housing 10 guided.

The sliding element 20 is by means of an elastic element 60 in the form of a helical compression spring, which at the nozzle distal end in the injector 10 is trapped, against a spacer element 64 urged, which as before according to the embodiment according to 1 to 4 at the nozzle end 14 in the injector housing 10 is arranged. The elastic element 60 pushes against the nozzle-distal end of the displacement element 20 , in the present case against a closure plate 98 on the magnetic packet or the magnet arrangement 42 which (s) to the anchor space 92 at the nozzle distal end of the same is adjacent thereto or adjacent thereto. This exceeds that of the compression spring element 60 generated compressive force in valve closing direction -A, which on the sliding element 20 acts, in turn, the maximum intended operating pressure, which in the valve opening direction + A on the sliding element 20 acts. The valve member 26 allowed stroke is limited by a stop surface 65 at the nozzle-near end of the body 50 , against which a shoulder surface 66 on the valve member 26 can get to the plant.

Obvious, s. 5 , is the magnetic package 42 or the magnet arrangement, which (s) at the nozzle distal end of the armature space 92 is arranged adjacent to this, in this embodiment of the injector 1 via a sealing compensating element 100 from the anchor room 92 (Media) separately. This is a union nut 102 the sliding element 20 in an advantageously simple way to the magnet assembly 42 on the body 50 to attach and at the same time the sealing compensation element 100 between the anchor space 92 and the magnet assembly 42 or the magnetic space 104 to catch or fix. This easy-to-install design allows maintenance on the injector 1 effortlessly succeed, z. B. for the purpose of replacing the magnet assembly 42 , next to it is the magnet space 104 protected against the entry of aggressive reducing agent.

The compensation element 100 comprises a membrane section in the form of an elastomeric membrane seal 106 , which extends radially and peripherally on the base body 50 ie at the open end of the chamber 52 , sealingly resting. In a (central) bore 108 of the magnetic package 42 (The iron core) into it, extends adjacent, ie axially in the opening direction + A, an elastically expandable section or element 110 of the compensation element 100 , which is formed as a (pleated) bellows. To an extension of the compensation element 100 in the intended manner with freezing of reducing agent in the armature space 92 to allow for an increase in volume is between the magnet assembly 42 , ie its nozzle-near end, and the membrane seal 106 still a compensation room 112 formed, in which these under pressure from the armature space 92 can dive (in 5 Not shown). Next to it is the bellows 110 at the nozzle-distal end, a space for a corresponding elastic expansion in icing conceded, ie in the bore 108 ,

The 6 to 10 , which will be discussed in more detail below, show further details with regard to possible variants of a design and arrangement of the compensation element 100 ,

According to an embodiment according to 6 is provided that the compensation room 112 for an expansion of the elastomeric membrane 106 at the nozzle near end of the magnet assembly 42 is formed as an annular space, in particular by the same in the potting compound of the magnetic packet 42 , The annulus 112 communicates with the environment, allowing a retraction of the elastomeric membrane 106 when putting the injector out of operation 1 in any case is possible. Obvious here is the nozzle-distal end of the bellows 110 further spring-loaded (spring 140 with support disk 142 ), which causes the bellows 110 does not move in an injection mode. The feather 140 However, allows expansion of the bellows 110 from 1.5 to 2 times the injection pressure, ie corresponding to the pressure level at icing.

7 shows a modification of the compensation element 100 to the effect that between the elastomer bellows 110 and the elastomeric membrane 106 a support ring 144 introduced from sheet metal, in particular vulcanized, is.

8th illustrates a variant of the injector 1 in which the compensation element 100 a membrane 106 which is made using sheet metal. This - also in 9 shown compensation element 100 - points in areas 114 the membrane 106 , which are intended for investment, a slip-resistant and well-sealing elastomeric coating, while the sheet-metal diaphragm shafts 116 just lie. The elastomer bellows 110 is vulcanised onto the membrane sheet.

10 further shows a variant in which the bellows 110 eliminated. Instead, the membrane 106 relatively large compensation spaces 112 conceded, wherein the membrane 106 preferably completely made of elastomer. In order to be able to form the magnetic circuit or the magnetic flux (arrows) as intended, there are flux-conducting elements 117 in the form of an intermediate ring 118 made of magnetic material and a magnetic bridge 120 used. ventilation holes 122 in the anchor plate 44 allow the reductant displacement for the operation of the injector 1 , It should be noted that another ventilation hole 146 in the closure plate 98 can be provided.

The injector 1 according to the second embodiment, s. 5 , a number, in particular two, (tubular) ventilation channels 124 . 126 on which ever communicates with these, from the anchor room 92 to the nozzle room 34 through the main body 50 extend. Here is at least one ventilation channel 124 with a nozzle-side mouth 128 near the needle seat 28 led - in such a way that this end 128 when opening the nozzle valve 30 experiences a significant suction effect - while the nozzle space mouth 130 the further channel 126 relatively further from the nozzle seat 28 is removed and experiences no such or a weaker suction effect. Due to the suction effect at the first mouth 128 becomes reducing agent via the ventilation channel 124 from the anchor room 92 discharged, but to compensate for the pressure imbalance generated over the other ventilation channel 126 from the nozzle room 34 in the anchor room 92 tracked. This advantageously allows a circulation of the reducing agent and an undesired aging of reducing agent in the armature space 92 avoided, the same in operation also cooled advantageous. At the same time can advantageously a penetration of the ice in freezing of the reducing agent from the armature space 92 towards the nozzle room 34 over the channels 124 . 126 followed, whereupon its increasing pressure load an intended relief by moving the sliding element 20 can cause.

The injector 1 according to 5 also has leakage lines 132 on to inadvertently into the internal cavity 12 or in the magnet room 104 allowed to drip occurred reducing agent can. The injector 1 according to 5 , also conceivable for the injector 1 According to the first embodiment, optionally an outlet 134 from the nozzle room 34 have, so that a cooling flushing in operation is possible with constant flow. The near the jet end 14 formed inlet channel 36 and the outlet 134 can to form a swirl flow in the nozzle chamber 34 be guided for improved cooling of the same tangential to this, in particular with parallel, but radially offset arrival and Abströmrichtungen B and C, 11 ,

General is for the embodiments according to three and 4 - Also conceivable for the other embodiments according to 1 . 2 and 5 - Provided the sliding element 20 secured against rotation in the injector housing 10 to arrange, for. B. by means of corresponding engagement elements (not shown).

LIST OF REFERENCE NUMBERS

1

injector

10

injector

12

inner space

14

first end 10

16

Nozzle assembly / nozzle

20

Displacement member / member

22

Inner surface area 10

24

Outer casing surface 20

26

valve member

28

valve seat

30

nozzle valve

32

bolt head 26

34

nozzle chamber

36

inlet channel

40

Valve operating structure

42

magnet assembly

44

Anchor (plate)

46

Return spring

50

body

52

(first) chamber

54

second chamber

56

cover element

57

supply line

58

guide

59

collar

60

elastic element

62

Housing (screw) for use

63

housing cover 10

64

spacer

65

stop surface

66, 96

shoulder surface 26

68

diaphragm seal

70

Phase transition compensation element

72

filling medium 70

74

pull bar

75

translation element

76

attack surface

77

lever arm

78

membrane

80

washer

82

pressure spring

84

opening 10

86

Seal (ring)

88

Intake

90

opening 10

92

armature space

94

shell

96

shoulder surface 26

98

closing plate

100

compensation element

102

Nut

104

magnetic space

106

Membrane (gasket)

108

Opening (sbohrung) 42

110

expandable element

112

compensation chamber

114

Area 106

116

diaphragm shaft

117

flux collector

118

intermediate ring

120

bridge

122

ventilation hole

124

ventilation channel

126

ventilation channel

128

muzzle 124

130

muzzle 126

132

leakage line

134

outlet

140

feather

142

support disc

144

support ring

146

ventilation hole

A

Valve actuation direction / axial direction

+ A

Valve closing direction

-A

Valve opening direction

B

flow direction

C

outflow

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• DE 102010045509 A1 [0003]
• DE 102009032488 A1 [0003]
• DE 102009032487 A1 [0004]

Claims (20)

Injector ( 1 ) for reducing agents, in particular for an exhaust gas aftertreatment, furthermore in particular for a motor vehicle, wherein the injector ( 1 ) comprises: - an injector housing ( 10 ) with at least one inlet channel ( 36 ) for reducing agent, which in a nozzle chamber ( 34 ) of the injector ( 1 ) opens; A nozzle arrangement ( 16 ) and by means of a valve member ( 26 ) and a valve seat ( 28 ) formed nozzle valve ( 30 ), via which a flow path from the nozzle chamber ( 34 ) to the nozzle assembly ( 16 ) is selectively releasable for application of reduction agent; A valve actuation assembly ( 40 ) for the axial displacement of the valve member ( 26 ) in a valve operating direction (A) for selectively releasing the flow path; characterized in that the injector ( 1 ) a displacement element ( 20 ), wherein the displacement element ( 20 ) in the valve actuation direction (A) displaceable and by an elastic element ( 60 ) in the valve closing direction (-A) urged in the Injektorgehäuse ( 10 ) is received such that upon displacement of the displacement element ( 20 ), in particular in the course of a freezing of reducing agent, the nozzle chamber volume is varied. Injector ( 1 ) according to claim 1, characterized in that on the displacement element ( 20 ) the valve actuator assembly ( 40 ) is received, and / or the valve member ( 26 ) on the displacement element ( 20 ) is received and / or guided. Injector ( 1 ) according to one of the preceding claims, characterized in that the displacement element ( 20 ) by means of the elastic element ( 60 ) against a nozzle-side spacer element ( 64 ) in the injector housing ( 10 ) is urged. Injector ( 1 ) according to one of the preceding claims, characterized in that the elastic element ( 60 ) a force on the displacement element ( 20 ) in the valve closing direction (-A) which is greater than a predetermined maximum operating pressure force on the displacement element ( 20 ) in the valve opening direction (+ A), especially 1.5 to 2 times. Injector ( 1 ) according to one of the preceding claims, characterized in that the nozzle space ( 34 ) by means of the displacement element ( 20 ) is formed such that when ice formation in the nozzle chamber ( 34 ) an expansion of the ice in the opening direction (+ A) of the nozzle valve ( 30 ) is channeled, in particular by means of decreasing opening cross-section of the nozzle chamber ( 34 ) in the valve opening direction (+ A). Injector ( 1 ) according to one of the preceding claims, characterized in that the injector ( 1 ) further comprises at least one phase transition compensation element ( 70 ), by means of which in a phase transition at the same from liquid to solid, in particular in the course of freezing, a force in the opening direction (+ A) on the valve member ( 26 ) is exercised, in particular the flow path from the nozzle chamber ( 34 ) to the nozzle assembly ( 16 ) is released. Injector ( 1 ) according to claim 6, characterized in that the phase transition compensating element ( 70 ) a filling medium ( 72 ), whose phase transition from liquid to solid during freezing before the phase transition of a with the injector ( 1 ) performs reducing agent. Injector ( 1 ) according to one of claims 6 to 7, characterized in that the phase transition compensation element ( 70 ) on the displacement element ( 20 ) is received and / or fixed, in particular with this in the injector housing ( 10 ) is taken together axialverschieblich. Injector ( 1 ) according to one of the preceding claims, characterized in that the phase transition compensation element ( 70 ), in particular in the form of a membrane can, with the valve member ( 26 ) is operatively connected, in particular via a pull rod ( 74 ) on the valve member ( 26 ) acts. Injector ( 1 ) according to one of claims 6 to 9, characterized in that by means of the phase transition compensation element ( 70 ) the valve member ( 26 ) when freezing into a stop ( 65 ), in particular for a seal on a guide ( 58 ) for the valve member ( 26 ). Injector ( 1 ) according to one of claims 6 to 10, characterized in that the phase transition of the phase transition compensation element ( 70 ) at a first freezing temperature and the phase transition of one with the injector ( 1 ) reducing agent at a second, compared to the first temperature lower freezing temperature, wherein the solidification temperature difference between the first and second temperature in the range of about 1 to 3 degrees Celsius. Injector ( 1 ) according to one of claims 1 to 5, characterized in that on the displacement element ( 20 ) an anchor space ( 92 ) of the valve actuator assembly ( 40 ), the armature space ( 92 ) in particular via a sliding element ( 20 ) formed leadership ( 58 ) for the valve member ( 26 ) with the nozzle space ( 34 ) communicates with the anchor space ( 92 ) of an adjacent magnetic space ( 104 ) of the valve actuator assembly ( 40 ), especially at the nozzle distal end of the anchor space ( 92 ), by means of a compensation element ( 100 ), in particular, however, is also sealed. Injector ( 1 ) according to claim 12, characterized in that the compensation element ( 100 ) a membrane ( 106 ) and / or an elastically expandable element ( 110 ), in particular a bellows, further in particular in combination. Injector ( 1 ) according to claim 13, characterized in that a nozzle-near end portion of a in the magnetic space ( 104 ) received magnet assembly ( 42 ) a compensation space ( 112 ), in particular annular space ( 112 ) into which the membrane (in which 106 ) when pressurized by the armature space ( 92 ) can expand. Injector ( 1 ) according to one of claims 13 and 14, characterized in that the elastically expandable element ( 110 ) of the compensation element ( 100 ) from the nozzle-near end of the magnet space ( 104 ) within the magnet assembly ( 42 ), in particular in a compensation opening ( 108 ), to a nozzle-remote end of the magnetic space ( 104 ). Injector ( 1 ) according to one of claims 12 to 15, characterized in that the elastically expandable element ( 110 ) is spring-loaded, such that an expansion of the same only after exceeding a pressure threshold above an operating pressure of the injector ( 1 ) is possible. Injector ( 1 ) according to one of claims 12 to 16, characterized in that in a basic body ( 50 ) of the displacement element ( 20 ) Ventilation channels ( 124 . 126 ) in communication with both the nozzle space ( 34 ) as well as the anchor space ( 92 ) are formed, in particular such that when opening the nozzle valve ( 30 ) a pressure imbalance between armature space mouths of the ventilation channels ( 124 . 126 ) is produced. Injector ( 1 ) according to one of claims 12 to 17, characterized in that the compensation element ( 100 ) with the magnet arrangement ( 42 ) with a tensioning element ( 102 ) against a base body ( 50 ) of the displacement element ( 20 ), in particular screwed. Injector ( 1 ) according to one of the preceding claims, characterized in that the magnetic space ( 104 ) via a radially extending membrane ( 68 ; 106 ) and / or an axially extending elastically expandable element ( 110 ) sealed against ingress of reducing agent and / or from the armature space ( 92 ) is disconnected. Exhaust after-treatment device with an injector ( 1 ) for reducing agent according to any one of the preceding claims.

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