DE102020201727A1 - System and procedure for exhaust gas aftertreatment - Google Patents

Abstract

An exhaust gas aftertreatment system comprises an exhaust pipe for guiding an exhaust gas flow; and a reducing agent injector which protrudes into the exhaust pipe and is designed to inject a reducing agent into the exhaust gas flow via an injection nozzle; wherein the injection nozzle comprises a nozzle pin which is arranged within a nozzle housing such that an injection channel is formed between an outer surface of the nozzle pin and an inner surface of the nozzle housing through which the reducing agent is ejected into the exhaust gas stream, the injection channel being shaped such that the Reducing agent is accelerated by it.

Description

Technical area

The present invention relates to a system and a method for exhaust gas aftertreatment and a motor vehicle which comprises such a system.

background

A catalytic converter is an exhaust gas purification device that converts toxic gases and pollutants in the exhaust gas of an internal combustion engine into less toxic or non-toxic substances and / or filters such substances from the exhaust gas flow. Catalysts are used in particular in internal combustion engines that run on either gasoline, diesel or another suitable fuel.

Selective Catalytic Reduction (SCR) is a well-known technique used in catalytic converters, in which nitrogen oxides, known as NOx, are converted into diatomic nitrogen and water with the help of a catalytic converter. A gaseous and / or liquid reducing agent, e.g. anhydrous ammonia, aqueous ammonia or urea, is added to an exhaust gas stream and adsorbed on the catalyst.

Traditionally, in the ammonia injection of an SCR system, a single injector protruding into the exhaust gas flow and a gas mixer arranged further downstream in the exhaust gas flow were used to distribute the injected ammonia in the exhaust gas, see eg the publication WO 2014/154936 A1 .

In order to reduce the back pressure generated by such a gas mixer and thus to increase fuel economy, multi-pipe injectors were introduced, in which each injector is provided with a fork-like geometry with a large number of injection holes in order to distribute the reducing agent during the injection, see e.g. the printed matter DE 2009 030 927 A1 . Due to the improved distribution of the reducing agent, a gas mixer is no longer required in this case. However, it is difficult to achieve pressure equality across the individual prongs of the fork geometry, which can impair the distribution performance of such a system.

Summary of the invention

Thus, there is a need to find more effective and flexible solutions for the operation of a reducing agent injection system of an exhaust gas aftertreatment system.

To this end, the present invention provides a system according to claim 1, a motor vehicle according to claim 10 and a method according to claim 11.

According to one aspect of the invention, a system for exhaust gas aftertreatment comprises an exhaust pipe for guiding an exhaust gas flow; and a reducing agent injector which protrudes into the exhaust pipe and is designed to inject a reducing agent into the exhaust gas flow via an injection nozzle; wherein the injection nozzle comprises a nozzle pin which is arranged within a nozzle housing such that an injection channel is formed between an outer surface of the nozzle pin and an inner surface of the nozzle housing through which the reducing agent is ejected into the exhaust gas stream, the injection channel being shaped such that the Reducing agent is accelerated by it.

According to a further aspect of the invention, a method for exhaust gas aftertreatment comprises injecting reducing agent with an injection nozzle of a reducing agent injector into an exhaust gas flow guided through an exhaust pipe, the reducing agent being ejected and accelerated through an injection channel into the exhaust gas flow, the injection channel being between an inner surface of a nozzle housing of the Reducing agent injector and an outer surface of a nozzle pin of the reducing agent injector is formed, which is arranged within the nozzle housing.

According to a further aspect of the invention, a motor vehicle comprises an internal combustion engine and a system for exhaust gas aftertreatment according to the invention.

One idea of the present invention is to eliminate the simple injection holes commonly used by a more sophisticated construction based on the principle of a jet nozzle. In the case of a jet nozzle, a fluid is accelerated to high speeds shortly before it emerges into a surrounding medium in order to generate a coherent and widely distributed fluid flow. This is achieved by guiding the fluid through a channel section with a reduced cross-sectional area. In addition, turbulence effects can further increase the spread of the injected reducing agent. By using relatively high pressures, a uniform distribution of the reducing agent at the inlet of the injection nozzle can be achieved, which leads to a uniform pressure distribution at the nozzle outlet. As a result, the mass flow and the mass distribution of the reducing agent in the exhaust gas flow can be significantly improved compared to conventional systems. Thus, the Performance of the entire exhaust aftertreatment system can be improved.

Advantageous refinements and developments result from the subclaims.

According to a further development of the invention, the nozzle pin can be designed to be movable within the nozzle housing in order to adapt a shape of the injection channel in accordance with an operating mode. In this way, injection parameters of the reducing agent injector can be set. Accordingly, the method can include moving the nozzle pin within the nozzle housing in order to adapt a shape of the injection channel in accordance with an operating mode.

For example, the nozzle pin can be moved between several discrete operating positions, each defining a particular operating mode by determining the shape of the injection channel based on the interaction between the outer shape of the nozzle pin and the inner shape of the nozzle housing. In another example, however, the nozzle pin can be moved continuously so that a gradual adjustment of the injection parameters can be possible.

In a first operating position of a specific example, the nozzle pin can completely close the injection channel and / or an inlet of the injection channel, so that no reducing agent is injected into the exhaust gas flow. This first operating position can thus represent an “off” mode of the reducing agent injector. In a second operating position of this example, the nozzle pin can be positioned in such a way that a laminar flow of the reducing agent through the injection channel is achieved. In a third operating position of the nozzle pin, the injection channel can be shaped in such a way that a turbulent flow of the reducing agent is achieved. In a fourth operating position the reducing agent can form stable flow eddies within a generally turbulent flow, i.e. the liquid can have regions in which the flow rotates about an axis which can be straight or curved. These circulating areas can spread along the injection channel and can be controlled in terms of shape and / or behavior, e.g. by adapting the geometry of the injection channels. Such eddies can be used to adapt the reducing agent distribution according to the respective application, e.g. different operating and / or driving conditions, different engine sizes, etc.

According to a development of the invention, the injection parameters can include a reducing agent injection angle, a reducing agent flow rate and / or a reducing agent flow type.

The reductant injection angle defines the angle at which the reductant is expelled relative to the exhaust gas stream. For example, high injection angles can lead to a wide spread and thus to a uniform distribution of the reducing agent in the exhaust gas. A higher flow rate of the reducing agent, on the other hand, can also lead to good distribution in the exhaust gas, since the reducing agent can penetrate better into the exhaust gas. The flow rate of the reducing agent during the injection can also influence the injection angle, e.g. a higher speed can lead to a smaller injection angle. The reducing agent flow types can include, without limitation, various forms of turbulent flow with or without unstable and / or stable eddies, but also laminar flow.

According to a further development of the invention, the injection channel can have a swirl chamber which is formed between an inner radius defined by the outer surface of the nozzle pin and an outer radius defined by the inner surface of the nozzle housing. The vortex chamber can be shaped in such a way that it generates flow vortices within the reducing agent by guiding the reducing agent at different flow speeds between the inner radius and the outer radius. Correspondingly, in a further development of the method, flow vortices can be generated within the reducing agent by passing the reducing agent through a vortex chamber in the injection channel at different flow speeds between an inner radius defined by the outer surface of the nozzle pin and an outer radius defined by the inner surface of the nozzle housing.

Vortices describe a special type of flow in which the particles of a fluid move in a circle along a defined axis in a virtual center. The rotation of the eddies can support their own stability, ie the circulating fluid structure can remain more or less constant. In the opposite case, the particles flow in undefined directions and thus do not form any coherent structures within the flow of the fluid. The appearance and behavior of the eddies can be calculated and predicted on the basis of the underlying mathematical description of the partially solved Navier-Stokes equation, e.g. on the basis of the Lamb-Oseen solution or the Lamb-Oseen model, which is a technically detailed Description of the vortex behavior and the possibility opens up the necessary conditions for the modification of its To determine the appearance. In other words, this allows the shape and / or behavior of a vortex to be controlled, for example its size / radius, focus and direction of propagation.

According to a further development of the invention, the nozzle pin can be designed to adapt a shape of the swirl chamber by movement within the nozzle housing. As a result, a vortex shape and / or a vortex flow behavior of the flow vortices generated can be adapted. Correspondingly, in a further development of the method, a shape of the vortex chamber can be adapted by moving the nozzle pin within the nozzle housing, whereby a vortex shape and / or a vortex flow behavior of the flow vortices generated is adapted.

By moving the nozzle pin relative to the nozzle housing, the size, diameter and general geometry of the swirl chamber or, more generally, that of the injection channel and thus of the volume through which the reducing agent flows can be varied and adapted in order to set certain vortex flow properties or, more generally, different injection parameters for the reducing agent that affect the injection angle of the Reducing agent, the flow rate of the reducing agent and / or the type of reducing agent flow include.

According to a further development of the invention, the nozzle pin can be designed to adapt a shape of a nozzle outlet to the injection nozzle by movement within the nozzle housing. Accordingly, in a further development of the method, a shape of a nozzle outlet of the injection nozzle can be adapted by moving the nozzle pin within the nozzle housing.

The injection angle of the reducing agent can be changed, for example, by partially moving the nozzle pin at the nozzle outlet out of the nozzle housing, so that the nozzle pin forms a projection opposite the nozzle housing, which then deflects the reducing agent jet away from a central axis of the injection nozzle.

According to a development of the invention, the injection nozzle can be arranged along a central axis of the exhaust pipe and aligned downstream with respect to the exhaust gas flow.

This design combines a high mixing quality of the reducing agent with a very low counter pressure of the reducing agent injector, since a single centralized jet nozzle with a minimal cross-section is provided, which is nevertheless able to generate a uniform flow of reducing agent over the entire cross-section of the exhaust pipe. Pressure fluctuations, as they are known from conventional fork-shaped systems, are thus avoided. In addition, no gas mixer is required.

According to a development of the invention, the reducing agent injector can further comprise a nozzle actuator which is designed to cause the nozzle pin to move.

For example, an electromechanical and / or electromagnetic actuator can be used, e.g. on the basis of a magnetic drive. However, other actuator technologies can be used, which include, without limitation, mechanical variants, e.g. on the basis of a screw (similar e.g. to the setting of a carburetor), hydraulic actuators, pneumatic actuators or other pressure-regulated devices, etc.

According to a development of the invention, the nozzle actuator can be arranged along a central axis of the exhaust pipe and aligned upstream with respect to the exhaust gas flow relative to the injection nozzle.

The actuator can thus be arranged directly behind the injection nozzle relative to the exhaust gas flow in such a way that the smallest possible cross-sectional area is generated in order to minimize the back pressures of the injection system.

The present invention is explained in more detail below with reference to the exemplary embodiments specified in the schematic figures.

Figure list

• 1 zeigt schematisch ein System zur Abgasnachbehandlung gemäß einer Ausführungsform der Erfindung in einem ersten Betriebsmodus.
• 2 zeigt das System aus 1 in einem zweiten Betriebsmodus.
• 3 zeigt ein Flussdiagramm eines Verfahrens zur Abgasnachbehandlung unter Verwendung des Systems aus 1 und 2.\
• 4 zeigt schematisch ein Kraftfahrzeug umfassend das System zur Abgasnachbehandlung von 1 und 2.
• 5 zeigt schematisch eine Querschnittsansicht einer Einspritzdüse, wie sie in dem System aus 1 und 2 in dem ersten Betriebsmodus verwendet wird.
• 6 zeigt schematisch die Einspritzdüse aus 5 in dem zweiten Betriebsmodus.
• 7 zeigt schematisch eine detaillierte Querschnittsansicht der Einspritzdüse aus 5.
• 8 zeigt schematisch eine detaillierte Querschnittsansicht der Einspritzdüse aus 6.
• 9 zeigt schematisch eine weitere detaillierte Querschnittsansicht der Einspritzdüse aus 5.
• 10 zeigt schematisch eine weitere detaillierte Querschnittsansicht der Einspritzdüse aus 6.

The accompanying figures are intended to provide a further understanding of the invention and form part of the present disclosure. They illustrate embodiments of the invention and, together with the description, serve to explain principles and concepts of the invention. Other embodiments of the invention and many of the recited advantages of the invention will become apparent in view of the following detailed description. The elements of the drawings are not necessarily shown to scale with one another. In the figures, the same reference symbols denote the same or functionally identical elements, unless stated otherwise.

• 1 shows schematically a system for exhaust gas aftertreatment according to an embodiment of the invention in a first operating mode.
• 2 shows the system 1 in a second operating mode.
• 3 FIG. 13 shows a flow diagram of a method for exhaust gas aftertreatment using the system from FIG 1 and 2 . \
• 4th shows schematically a motor vehicle comprising the exhaust gas aftertreatment system from 1 and 2 .
• 5 FIG. 11 shows schematically a cross-sectional view of an injection nozzle as used in the system of FIG 1 and 2 is used in the first mode of operation.
• 6th shows schematically the injection nozzle from 5 in the second mode of operation.
• 7th FIG. 11 shows schematically a detailed cross-sectional view of the injection nozzle from FIG 5 .
• 8th FIG. 11 shows schematically a detailed cross-sectional view of the injection nozzle from FIG 6th .
• 9 FIG. 11 schematically shows a further detailed cross-sectional view of the injection nozzle from FIG 5 .
• 10 FIG. 11 schematically shows a further detailed cross-sectional view of the injection nozzle from FIG 6th .

Although specific exemplary embodiments are illustrated and described herein, it will be apparent to those skilled in the art that a variety of alternative and / or equivalent implementations can be substituted for the specific exemplary embodiments illustrated and described without departing from the scope of the present invention. In general, the application covers any adaptations or variations of the specific exemplary embodiments described herein.

Detailed description of the exemplary embodiments

1 shows schematically a system 10 for exhaust gas aftertreatment according to an embodiment of the invention in a first operating mode. The system is in 2 shown in a second operating mode.

In detail, the system includes 10 an exhaust pipe 1 for guiding an exhaust gas flow 3 and a reducing agent injector 2 , which with an injection body 15th into the exhaust pipe 1 protrudes and is designed to be a reducing agent 8th via an injection nozzle 4th into the exhaust gas flow 3 inject that at a distal end of the injection body 15th is arranged. The injector 4th is along a central axis 3 of the exhaust pipe 1 arranged and in relation to the exhaust gas flow 3 aligned downstream.

The system 10 is designed to control the exhaust gas flow 3 to clean, which for example from an internal combustion engine 101 , for example a diesel engine, a motor vehicle 100 , e.g. as in 4th represented, is ejected. To this end, the system can 10 furthermore comprise a sequence of exhaust gas aftertreatment devices, to which in particular a device for selective catalytic reduction (SCR) belongs (not shown). The reducing agent injector 2 is arranged upstream of the SCR device in order to introduce reducing agents, for example in liquid form, into the exhaust gas flow 3 injected, which is used in the catalytic process within the SCR device in the usual way as a reducing agent.

The injector 4th includes a nozzle pin 5 in a rotationally symmetrical configuration around one in the direction of the exhaust gas flow 3 pointing axial direction. The nozzle pin 5 is inside a nozzle housing 6th positioned so that an injection port 7th between an outer surface 5a of the nozzle pin 5 and an inner surface 5b of the nozzle housing 6th is formed. This is in detail in 5 until 10 to see the schematic cross-sectional views of the in the system of FIG 1 and 2 used injector 4th along the axial direction of the nozzle pin 5 show. As can be seen here, the nozzle housing encloses 6th the nozzle pin 5 in the circumferential direction.

A reducing agent 8th is at a nozzle inlet 16 into the injection port 7th directed, the combined arrangement of nozzle pin 5 and nozzle housing 6th fulfills the function of a jet nozzle. The injection port is concrete 7th shaped so that it contains the reducing agent 8th accelerated by increasing the flow area of the reducing agent 8th reduced, ie the cross-sectional area that the reducing agent 8th when entering the injector 4th flows through. The reducing agent 8th is from the nozzle inlet 16 through the injection port 7th and at a nozzle outlet 12th from the injector 4th into the exhaust gas flow 3 pushed out. Thereby the reducing agent 8th through the nozzle housing 6th around the nozzle pin 5 around, i.e. through the injection port 7th flushed.

By using the principle of a jet nozzle, it is possible to achieve a very even and broad distribution of the reducing agent 8th in the exhaust stream 3 to reach. The reducing agent can do this 8th with a high pressure of, for example, approx. 9 bar to 15 bar into the nozzle inlet 16 be pumped to ensure an even distribution of the reducing agent 8th at the nozzle inlet 16 and at the nozzle outlet 12th to guarantee.

Further is the nozzle pin 5 inside the nozzle housing 6th designed to be movable to a shape of the injection channel 7th adapt accordingly to different operating modes and thereby the injection parameters of the reducing agent injector 2 as explained below.

As an example, in 1 and 2 two modes of operation of the system 10 shown, a first operating mode ( 1 ) and a second operating mode ( 2 ). 5 , 7th and 9 show detailed views of the injection nozzle 4th for the first operating mode while 6th , 8th and 10 the injector 4th show in the second operating mode.

The first operating mode is referred to below as “focused mode”, while the second operating mode is referred to as “defocused mode”. In the focused operating mode, the reducing agent 8th at a negative reductant injection angle α ejected, which means that the flow of the reducing agent 8th to the central axis 13th of the exhaust pipe 1 is focused or collapsed (cf. 1 ). In the defocused mode, however, the reducing agent is 8th at a positive reductant injection angle α in the direction of the exhaust pipe 1 pushed out. The reductant injection angle α can be varied (cf. 2 ).

Both operating modes correspond to different positions of the nozzle pin 5 inside the nozzle housing 6th . In the first mode of operation, the nozzle pin 5 inside into the nozzle housing 6th moved, ie downstream with respect to the direction of flow of the reducing agent 8th and thus the exhaust gas flow 3 . In the second mode of operation, the nozzle pin 5 compared to the first operating mode from the nozzle housing 6th moved out. The nozzle pin 5 and the nozzle housing 6th are shaped so that the injection port 7th when moving the nozzle pin out 5 from the nozzle housing (left side in 6th ) is expanded in some sections. This has the consequence that the flow behavior of the reducing agent 8th inside the injection channel 7th opposite the position of the nozzle pin 5 in 5 changes. In addition, the geometry of the nozzle outlet is also determined 12th adapted (right side in 6th ).

Due to the different shapes and arrangements of the injection channel 7th and the nozzle outlet 12th In both operating modes, the flow behavior and thus the injection parameters are different in both cases. By appropriately configuring the outer surface 5a of the nozzle pin 5 and the inner surface 6a of the nozzle housing 6th the injection parameters including the reducing agent injection angle α, the reducing agent flow rate v1-v3 and the reducing agent flow type can be varied. This enables the injection process to be carried out by simply moving the nozzle pin 5 inside the nozzle housing 6th can be adjusted in a convenient way. This can occur during the operation of the exhaust aftertreatment system 10 , ie while the vehicle is in operation 100 , respectively.

About the movement of the nozzle pin 5 To facilitate, includes the reductant injector 2 furthermore a nozzle actuator 14th , which is designed to control the movement of the nozzle pin 5 to cause. In the embodiment described here as an example, the nozzle actuator is 14th along the central axis 13th of the exhaust pipe 1 arranged and in relation to the exhaust gas flow 3 upstream of the injector 4th aligned to increase the cross-sectional area of the reductant injector 2 and thus to avoid the flow resistance.

The illustrated exemplary embodiment of the injection nozzle 4th also consists of a vortex chamber 9 as a recess inside the nozzle housing 6th is formed and in the axial direction around the nozzle pin 5 all around the inner surface 6a of the nozzle housing 6th runs (the vortex chamber 9 this version thus has an annular shape). The vortex chamber 9 serves to further modify the reducing agent flow 8th through the injection port 7th . The vortex chamber is for this purpose 9 between an inner radius passing through the outer surface 5a of the nozzle pin 5 is defined, and an outer radius passing through the inner surface 6a of the nozzle housing 6th is defined, arranged and shaped such that they flow vortices 11 within the reducing agent 8th generated by using the reducing agent 8th leads at different flow velocities between the inner radius and the outer radius.

It goes without saying that the embodiment shown is merely an example and that the person skilled in the art can provide vortex chambers with other shapes. In addition, more than one vortex chamber can be advantageous in certain applications, for example several annular vortex chambers which are arranged one behind the other in the axial direction. In addition, the injection port 7th be divided into several separate channels, which are located at the nozzle inlet 16 and / or nozzle outlet 12th may or may not unite.

The vortex chamber of the present exemplary embodiment is shown in FIG 7th and 9 for the focused mode in which the reducing agent 8th the vortex chamber 9 runs along an outer radius at a first speed v1 which is higher than a second speed v2 of the reducing agent 8th moving along an inner radius. The inner radius corresponds to a much shorter flow path than the path along the outer radius. When these different flow paths at the end of the vortex chamber 9 are brought together again, the different speeds induce a rotary movement within the stream of reducing agent 8th whereby under certain Conditions stable flow vortices 11 develop. These vortices 11 can then move along the injection channel 7th spread out and at the nozzle outlet 12th be expelled (cf. 9 ). The flow vortices 11 can occur during the flow process of the reducing agent 8th expand (cf. 9 ). The shape of the nozzle outlet 12th can also be used to determine the direction of the flow vortex 11 and define their focus.

By moving the nozzle pin 5 relative to the nozzle housing 6th the conditions of vortex generation can be changed. So can the nozzle pin 5 are moved in order to adapt various properties of the eddy current, for example a vortex shape and / or a vortex flow behavior of the flow vortices generated 11 .

This can be used to further adapt the process of discharging the reducing agent 8th be used.

In the defocused mode of the 2 , 6th , 8th and 10 generates the reducing agent 8th no stable eddies because of the difference in speeds v1-v3 inside the vortex chamber 9 is not large enough to produce stable flow vortices 11 to induce. Vortices can be created, but they are unstable and eventually collapse. The flow of the reducing agent 8th however, it can still be turbulent. By gradually moving the nozzle pin 5 inside the nozzle housing 6th and appropriate configuration of the inner surface 6a of the nozzle housing 6th and the outer surface 5a of the nozzle pin 5 can be the behavior of the flow vortex 11 can be varied. Variations from "sharp" and stable eddies to normal turbulent flow with unstable eddies up to laminar flow are possible.

In the focused mode, a suitable configuration of the nozzle outlet 12th used to be the collision / focus point of the reductant 8th inside the exhaust pipe 1 to adjust. More generally speaking, the nozzle outlet 12th also in the defocused mode for adjusting the reducing agent injection angle α be used. In general, the reducing agent injection angle becomes α a function of the diameter of the exhaust pipe 1 and the flow rate of the exhaust gas stream 3 , the shape of the nozzle outlet 12th and the flow behavior of the reducing agent 8th inside the injection channel 7th This in turn is due to the differences in speed of the various flow paths within the injection channel 7th is determined.

As a result, a reducing agent injector based on the jet principle is available, which achieves a uniform expansion of the injected reducing agent over the cross section of the exhaust pipe and thus the SCR device and thus effectively improves the SCR efficiency compared to conventional systems. The system can use a single nozzle in a central position with minimal cross-sectional area and thus minimal flow resistance. In other embodiments, however, a plurality of injection nozzles can also be used, each of which is configured as a jet nozzle.

In addition, the system offers improved control over the injection parameters through the use of a vortex principle within a jet nozzle. This enables the nozzle design to be adapted for different applications (e.g. different pipe diameters or motor sizes) and for different operating points by actively moving the nozzle pin during operation.

A corresponding procedure M. for exhaust aftertreatment is in 3 shown schematically. The procedure M. includes moving the nozzle pin under M0 5 inside the nozzle housing 6th to find a shape of the injection port 7th adapt according to an operating mode, whereby injection parameters of the reducing agent injector 2 can be set. The procedure M. further comprises under M1 injection of reducing agent 8th with the injector 4th of the reducing agent injector 2 into the through the exhaust pipe 1 guided exhaust gas flow 3 . Here is the reducing agent 8th through the injection port 7th into the exhaust gas flow 3 ejected and accelerated. Vortex 11 can within the reducing agent 8th can be generated by the reducing agent 8th through the vortex chamber 9 in the injection port 7th with different flow rates between one through the outer surface 5a of the nozzle pin 5 defined inner radius and one through the inner surface 6a of the nozzle housing 6th defined outer radius is performed.

In the preceding detailed description, various features for improving the stringency of the presentation have been summarized in one or more examples. It should be clear, however, that the above description is merely illustrative, but not restrictive in nature. It serves to cover all alternatives, modifications and equivalents. Many other examples will be immediately apparent to those skilled in the art on the basis of their technical knowledge in view of the above description. The exemplary embodiments were selected and described in order to be able to illustrate the principles on which the invention is based and its possible applications in practice so that those skilled in the art will be able to understand the invention and its various To optimally modify and use exemplary embodiments in relation to the intended purpose.

List of reference symbols

1

Exhaust pipe

2

Reducing agent injector

3

Exhaust gas flow

4th

Injector

5

Nozzle pin

5a

Outer surface of the nozzle pin

6th

Nozzle housing

6a

Inner surface of the nozzle housing

7th

Injection port

8th

Reducing agent

9

Vortex chamber

10

Exhaust aftertreatment system

11

Vortex

12th

Nozzle outlet

13th

central axis

14th

Nozzle actuator

15th

Injection body

16

Nozzle inlet

v1-v3

Reductant flow rates

α

Reduction injection angle

100

Motor vehicle

101

Internal combustion engine

M.

procieedings

M0-M1

Process step

QUOTES INCLUDED IN THE DESCRIPTION

This list of the documents listed by the applicant was 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.

Patent literature cited

• WO 2014/154936 A1 [0004]
• DE 2009030927 A1 [0005]

Claims (15)

System (10) for exhaust gas aftertreatment comprising: an exhaust pipe (1) for guiding an exhaust gas flow (3); and a reducing agent injector (2) which protrudes into the exhaust pipe (1) and is designed to inject a reducing agent (8) into the exhaust gas flow (3) via an injection nozzle (4); wherein the injection nozzle (4) comprises a nozzle pin (5) which is arranged within a nozzle housing (6) in such a way that an injection channel (7) between an outer surface (5a) of the nozzle pin (5) and an inner surface (6a) of the nozzle housing ( 6), through which the reducing agent (8) is ejected into the exhaust gas flow (3), the injection channel (7) being shaped in such a way that the reducing agent (8) is accelerated through it. System (10) according to Claim 1 , wherein the nozzle pin (5) is movably designed within the nozzle housing (6) to adapt a shape of the injection channel (7) according to an operating mode and thereby to set injection parameters of the reducing agent injector (2). System (10) according to Claim 2 wherein the injection parameters include at least one of the following parameters: a reductant injection angle (α), a reductant flow rate (v1-v3), and a reductant flow type. System (10) according to one of the Claims 1 until 3 , wherein the injection channel (7) has a swirl chamber (9) which is formed between an inner radius defined by the outer surface (5a) of the nozzle pin (5) and an outer radius defined by the inner surface (6a) of the nozzle housing (6), the Vortex chamber (9) is shaped in such a way that it generates flow vortices (11) within the reducing agent (8) in that the reducing agent (8) is guided at different flow speeds between the inner radius and the outer radius. System (10) according to Claim 4 wherein the nozzle pin (5) is designed to adapt a shape of the vortex chamber (9) by movement within the nozzle housing (6) and thereby adapt a vortex shape and / or a vortex flow behavior of the flow vortices (11) generated. System (10) according to one of the Claims 1 until 5 wherein the nozzle pin (5) is designed to adapt a shape of a nozzle outlet (12) of the injection nozzle (4) by movement within the nozzle housing (6). System (10) according to one of the Claims 1 until 6th wherein the injection nozzle (4) is arranged along a central axis (13) of the exhaust pipe (1) and is oriented downstream with respect to the exhaust gas flow (3). System (10) according to one of the Claims 1 until 7th wherein the reducing agent injector (2) further comprises a nozzle actuator (14) which is designed to cause a movement of the nozzle pin (5). System (10) according to Claim 8 wherein the nozzle actuator (14) is arranged along a central axis (13) of the exhaust pipe (1) and is oriented upstream with respect to the exhaust gas flow (3) relative to the injection nozzle (4). Motor vehicle (100) with an internal combustion engine (101) and a system (10) for exhaust gas aftertreatment according to one of the Claims 1 until 9 . Method (M) for exhaust gas aftertreatment, comprising: Injection (M1) of reducing agent (8) with an injection nozzle (4) of a reducing agent injector (2) into an exhaust gas flow (3) guided through an exhaust pipe (1), the reducing agent (8) through an injection channel (7) into the exhaust gas flow ( 3) is ejected and accelerated, the injection channel (7) between an inner surface (6a) of a nozzle housing (6) of the reducing agent injector (2) and an outer surface (5a) of a nozzle pin (5) of the reducing agent injector (2) is formed, which is arranged inside the nozzle housing (6). Procedure (M) according to Claim 11 , further comprising: moving (M0) the nozzle pin (5) within the nozzle housing (6) in order to adapt a shape of the injection channel (7) according to an operating mode, whereby injection parameters of the reducing agent injector (2) are set. Method (M) according to one of the Claims 11 and 12th , wherein flow vortices (11) are generated within the reducing agent (8) by the reducing agent (8) defined by a vortex chamber (9) in the injection channel (7) with different flow velocities between one defined by the outer surface (5a) of the nozzle pin (5) Inner radius and an outer radius defined by the inner surface (6a) of the nozzle housing (6). Procedure (M) according to Claim 13 , wherein a shape of the vortex chamber (9) is adjusted by moving the nozzle pin (5) within the nozzle housing (6), whereby a vortex shape and / or a vortex flow behavior of the generated flow vortices (11) is adapted. Method (M) according to one of the Claims 12 until 14th wherein a shape of a nozzle outlet (12) of the injection nozzle (4) is adjusted by moving the nozzle pin (5) within the nozzle housing (6).

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