Exhaust gas aftertreatment system and method

Abstract

The invention relates to an exhaust gas aftertreatment system, comprising an exhaust pipe for conducting an exhaust gas stream, and a reductant injector configured to protrude into the exhaust pipe and to inject reductant into the exhaust gas stream through an injector nozzle, wherein the injector nozzle comprises a nozzle pin arranged within a nozzle housing such that a jet channel is formed between an outer side surface of the nozzle pin and an inner side surface of the nozzle housing through which the reductant is discharged into the exhaust gas stream, the jet channel being formed such that the reductant is accelerated.

Description

Technical Field

[0001] This invention relates to an exhaust gas aftertreatment system and method, as well as a vehicle including the system. Background Technology

[0002] A catalytic converter is an emissions control device that converts toxic gases and pollutants in the exhaust gas from an internal combustion engine into less toxic or non-toxic substances, and / or filters these substances out of the exhaust gas stream. Catalytic converters are particularly suitable for internal combustion engines that use gasoline, diesel, or other suitable fuels.

[0003] Selective catalytic reduction (SCR) is a well-known technology used in catalytic converters, in which nitrogen oxides, known as NOx, are converted into nitrogen and water with the help of a catalyst. Gaseous and / or liquid reducing agents, such as anhydrous ammonia, ammonia solution, or urea, are added to the exhaust gas stream and adsorbed onto the catalyst.

[0004] Traditionally, ammonia injection in SCR systems typically uses an injector that extends into the exhaust gas flow and a gas mixer located further downstream in the exhaust gas flow to diffuse the injected ammonia into the exhaust gas (see, for example, WO2014 / 154936A1).

[0005] To reduce the back pressure generated by the gas-air mixer and thus improve fuel economy, a multiple-pipe injector was introduced. Each injector in a multiple-pipe injector has a fork-shaped structure with multiple injection holes to distribute the reducing agent during injection (see, for example, DE2009030927A1). Due to the improved reducing agent distribution, a gas-air mixer is no longer needed in this case. However, achieving pressure uniformity across the individual forks of the fork-shaped structure can be difficult and may affect the system's distribution performance. Summary of the Invention

[0006] (a) Technical problems to be solved

[0007] Therefore, there is a need to find a more efficient and flexible solution for the reductant injection system in the operation of exhaust gas aftertreatment systems.

[0008] Therefore, the present invention provides an exhaust gas aftertreatment system, a vehicle including the exhaust gas aftertreatment system, and an exhaust gas aftertreatment method.

[0009] (II) Technical Solution

[0010] According to one aspect of the invention, an exhaust gas aftertreatment system includes: an exhaust pipe for guiding an exhaust gas flow; and a reducing agent injector configured to protrude into the exhaust pipe and inject a reducing agent into the exhaust gas flow through an injector nozzle, wherein the injector nozzle includes a nozzle pin disposed 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, the reducing agent being discharged into the exhaust gas flow through the injection channel, the injection channel being configured to accelerate the reducing agent.

[0011] According to another aspect of the present invention, the exhaust gas aftertreatment method includes the following steps: injecting a reducing agent into an exhaust gas flow guided through an exhaust pipe via an injector nozzle of a reducing agent injector, wherein the reducing agent is accelerated through an injection channel and discharged into the exhaust gas flow, the injection channel being formed between the inner surface of the nozzle housing of the reducing agent injector and the outer surface of the nozzle pin of the reducing agent injector disposed within the nozzle housing.

[0012] According to another aspect of the invention, the vehicle includes: an internal combustion engine; and an exhaust aftertreatment system according to the invention.

[0013] The idea behind this invention is to eliminate the commonly used simple injector orifice through a more complex design based on the principle of a jet nozzle. When using a jet nozzle, the fluid is accelerated to high speed before being injected into the surrounding medium, generating a continuous and widely diffused fluid flow. This is achieved by guiding the fluid according to a channel section with a reduced cross-sectional area. Furthermore, turbulence effects can further increase the diffusion of the injected reducing agent. By utilizing relatively high pressure, a uniform distribution of the reducing agent can be achieved at the inlet of the injector nozzle, thereby achieving a uniform pressure distribution at the nozzle outlet. Therefore, compared to conventional systems, the mass flow and mass distribution of the reducing agent in the exhaust gas stream can be significantly improved, thereby enhancing the performance of the entire exhaust gas aftertreatment system.

[0014] Advantageous embodiments and improvements of the invention can be found in the dependent claims.

[0015] According to embodiments of the present invention, the nozzle pin can be configured to be movable within the nozzle housing to adjust the shape of the injection channel according to the operating mode, thereby adjusting the injection parameters of the reducing agent injector. Therefore, the above method may include the step of moving the nozzle pin within the nozzle housing to adjust the shape of the injection channel according to the operating mode.

[0016] For example, the shape of the injection channel is fixed based on the interaction between the outer shape of the nozzle pin and the inner shape of the nozzle housing, allowing the nozzle pin to move between several individual operating positions, each defining a specific operating mode. However, in another embodiment, the nozzle pin can move continuously, allowing for gradual adjustment of injection parameters. In a first operating position of a particular embodiment, the reducing agent is not injected into the exhaust gas flow because the nozzle pin can completely close the injection channel and / or the inlet of the injection channel. Therefore, the first operating mode position can represent the "off" mode of the reducing agent injector. In a second operating position of this embodiment, the nozzle pin can be positioned such that the reducing agent achieves laminar flow through the injection channel. In a third operating position of the nozzle pin, the injection channel can be configured to achieve turbulent flow of the reducing agent. In a fourth operating position, the reducing agent can form stable flow vortices in general turbulence, where the fluid has a region of rotation about a straight or curved axis. This rotational region can propagate along the injection channel, and its shape and / or behavior can be controlled, for example, by adjusting the shape of the injection channel. The distribution of the reducing agent can be adjusted using this vortex according to specific usage conditions, such as different operation and / or operating conditions, different engine sizes, etc.

[0017] According to embodiments of the present invention, the injection parameters may include the reducing agent injection angle, the reducing agent flow velocity, and / or the reducing agent flow type.

[0018] The reducing agent injection angle is defined as the angle at which the reducing agent is injected relative to the exhaust gas flow. For example, a larger reducing agent injection angle can lead to extensive diffusion of the reducing agent in the exhaust gas and thus a more uniform distribution of the reducing agent. On the other hand, a higher reducing agent flow velocity allows the reducing agent to penetrate the exhaust gas more effectively, so a higher reducing agent flow velocity can also lead to better distribution of the reducing agent within the exhaust gas. Furthermore, the flow velocity of the reducing agent during injection can also affect the reducing agent injection angle. For example, a higher flow velocity can result in a smaller injection angle. The type of reducing agent flow can include, but is not limited to, different forms of turbulence with or without unsteady and / or steady eddies, and can include laminar flow.

[0019] According to one embodiment of the invention, the injection channel may include a vortex chamber formed between an inner diameter defined by an outer surface of the nozzle pin and an outer diameter defined by an inner surface of the nozzle housing. The vortex chamber may be configured to guide the reducing agent at different flow velocities between the inner and outer diameters, thereby generating a flow vortex in the reducing agent. Therefore, in one embodiment of the method, a flow vortex in the reducing agent can be generated by guiding the reducing agent at different flow velocities through the vortex chamber within the injection channel between the inner diameter defined by the outer surface of the nozzle pin and the outer diameter defined by the inner surface of the nozzle housing.

[0020] A vortex represents a special type of flow in which fluid particles move in a circular path along an axis defined from a virtual center. The rotation of a vortex can support its own stability; that is, the rotating fluid structure can remain constant. Conversely, in the opposite case, particles flow in undefined directions, thus failing to form a coherent structure within the fluid flow. For example, the shape and behavior of vortices can be calculated and predicted based on the Lamb-Oseen scheme / model, according to the fundamental mathematical description of the partially solved Navier-Stokes equations. The Lamb-Oseen scheme / model provides a technically detailed description of vortex flow behavior and offers the possibilities for modifying vortex shapes. In other words, vortices can be controlled, for example, through their morphology and / or behavior, such as vortex size / radius, focus, and propagation direction.

[0021] According to one embodiment of the invention, the nozzle pin can be configured to adjust the shape of the vortex chamber by moving the nozzle pin within the nozzle housing, thereby adjusting the vortex shape and / or vortex flow behavior of the generated flow vortex. Therefore, in embodiments of the method, the shape of the vortex chamber can be adjusted by moving the nozzle pin within the nozzle housing, thereby adjusting the vortex shape and / or vortex flow behavior of the generated flow vortex.

[0022] By moving the nozzle pin relative to the nozzle housing, the size, diameter, and general geometry of the vortex chamber can be changed and adjusted, or more generally, the size, diameter, and general geometry of the injection channel and the resulting volume through which the reducing agent passes, to set specific vortex flow characteristics, or more generally, to set various injection parameters for the reducing agent, including the original agent injection angle, the reducing agent flow velocity, and / or the reducing agent flow type.

[0023] According to one embodiment of the invention, the nozzle pin can be configured to adjust the shape of the nozzle outlet of the injector nozzle by moving the nozzle pin within the nozzle housing. Therefore, in embodiments of the method, the shape of the nozzle outlet of the injector nozzle can be adjusted by moving the nozzle pin within the nozzle housing.

[0024] The reducing agent injection angle can be changed, for example, by partially moving the nozzle pin from the nozzle outlet toward the outside of the nozzle housing, so that a protrusion is formed by the nozzle pin opposite to the nozzle housing, which changes the direction of the reducing agent flow so that the reducing agent flow is away from the central axis of the injector nozzle.

[0025] According to one embodiment of the invention, the injector nozzle may be arranged along the central axis of the exhaust pipe and oriented downstream relative to the exhaust gas flow.

[0026] This embodiment employs a single, centrally located jet nozzle with a minimal cross-section, which provides high reductant mixing quality and low reductant counter pressure. Furthermore, this nozzle generates a uniform reductant flow across the entire cross-section of the exhaust pipe. Therefore, pressure fluctuations in conventional fork-type systems are avoided, and a gas mixer is not required.

[0027] According to one embodiment of the invention, the reducing agent injector may further include a nozzle actuator configured to drive movement of a nozzle pin.

[0028] For example, electromechanical and / or electromagnetic actuators based on solenoid actuators can be used. However, different actuator technologies can be used, including but not limited to mechanical variations, such as screw-based (similar to carburetor adjustment), hydraulic actuators, pneumatic actuators, or other pressure regulating devices.

[0029] According to one embodiment of the invention, the nozzle actuator can be arranged along the central axis of the exhaust pipe. Furthermore, the nozzle actuator can be oriented upstream relative to the exhaust gas flow.

[0030] Therefore, in order to minimize the back pressure of the injector system, the actuator can be arranged immediately behind the injector nozzle relative to the exhaust gas flow to form a minimum cross-section.

[0031] The invention will be explained in more detail with reference to the exemplary embodiments shown in the accompanying drawings. Attached Figure Description

[0032] The accompanying drawings, which are included in and constitute a part of this specification, are provided to better understand the invention. The drawings illustrate embodiments of the invention and, together with the description, serve to explain the principles of the invention. Other embodiments of the invention and the various advantages contemplated by the invention will be readily understood, as they can be better appreciated by referring to the following detailed description. The dimensions of the components in the drawings need not be precisely relative to each other. Unless otherwise stated, similar reference numerals denote similar or functionally similar components.

[0033] Figure 1An exhaust gas aftertreatment system according to an embodiment of the present invention is schematically shown during a first operating mode.

[0034] Figure 2 Shown during the second operating mode Figure 1 The system.

[0035] Figure 3 Showing the use Figure 1 and Figure 2 The flowchart shows the waste gas after-treatment method of the system.

[0036] Figure 4 Schematic illustration including Figure 1 and Figure 2 Vehicles with exhaust gas after-treatment systems.

[0037] Figure 5 The schematic diagram illustrates the operation during the first operating mode. Figure 1 and Figure 2 A cross-sectional view of the injector nozzle used in the system.

[0038] Figure 6 The schematic diagram illustrates the operation during the second mode. Figure 5 The injector nozzle.

[0039] Figure 7 schematically shown Figure 5 Detailed cross-sectional view of the injector nozzle.

[0040] Figure 8 schematically shown Figure 6 Detailed cross-sectional view of the injector nozzle.

[0041] Figure 9 schematically shown Figure 5 Other detailed cross-sectional views of the injector nozzle.

[0042] Figure 10 schematically shown Figure 6 Other detailed cross-sectional views of the injector nozzle.

[0043] Although specific embodiments of the invention have been shown and described herein, it will be apparent to those skilled in the art that various substitutions and / or equivalents may be used instead of the specific embodiments shown and described without departing from the scope of the invention. Generally, this application is intended to cover any modifications or variations of the specific embodiments discussed herein.

[0044] Explanation of reference numerals in the attached figures

[0045] 1: Exhaust pipe 2: Reducing agent injector

[0046] 3: Exhaust gas flow 4: Injector nozzle

[0047] 5: Nozzle pin 5a: Outer surface of the nozzle pin

[0048] 6: Nozzle housing 6a: Inner surface of the nozzle housing

[0049] 7: Injection channel; 8: Reducing agent

[0050] 9: Vortex chamber; 10: Exhaust gas after-treatment system

[0051] 11: Flowing vortex 12: Nozzle outlet

[0052] 13: Central shaft 14: Nozzle actuator

[0053] 15: Injector body 16: Nozzle inlet

[0054] v1-v3: Reducing agent flow velocity; α: Reducing agent injection angle

[0055] 100: Vehicle; 101: Internal Combustion Engine

[0056] M: Method M0-M1: Steps Detailed Implementation

[0057] Figure 1 The exhaust gas aftertreatment system 10 according to an embodiment of the present invention is schematically shown during a first operating mode. During a second operating mode, the exhaust gas aftertreatment system 10... Figure 2 As shown in the image.

[0058] Specifically, the exhaust gas aftertreatment system 10 includes: an exhaust pipe 1 for guiding the exhaust gas flow 3; and a reducing agent injector 2 configured to protrude into the exhaust pipe 1 together with the injector body, and to inject reducing agent 8 into the exhaust gas flow 3 through an injector nozzle 4 located at the end of the injector body 15. The injector nozzle 4 is arranged along the central axis 13 of the exhaust pipe 1 and faces downstream relative to the exhaust gas flow 3.

[0059] For example, the exhaust gas aftertreatment system 10 is configured to purify the exhaust gas from... Figure 4 The exhaust gas stream emitted by the internal combustion engine 101 (e.g., a diesel engine) of the vehicle 100 shown. For this purpose, the exhaust aftertreatment system 10 may further include a series of exhaust aftertreatment devices, including a selective catalytic reduction (SCR) device (not shown). A reducing agent injector 2 is arranged upstream of the SCR device to inject a reducing agent, for example, a liquid reducing agent, into the exhaust gas stream 3, which functions as a reducing agent in the conventional manner during the catalytic process within the SCR device.

[0060] The injector nozzle 4 includes a nozzle pin 5, which has a shape that is rotationally symmetrical about an axis pointing in the direction of the exhaust gas flow 3. The nozzle pin 5 is located within the nozzle housing 6, such that an injection channel 7 is formed between the outer surface 5a of the nozzle pin 5 and the inner surface 6a of the nozzle housing 6. This allows for... Figures 5 to 10 See in detail, Figures 5 to 10 schematically shown Figure 1 and Figure 2 The system uses a cross-sectional view of the injector nozzle 4 along the axial direction of the nozzle pin 5. It can be seen from this that the nozzle housing 6 surrounds the nozzle pin 5 circumferentially.

[0061] The reducing agent 8 moves from the nozzle inlet 16 into the injection channel 7, thereby enabling the combined arrangement of the nozzle pin 5 and the nozzle housing 6 to function as a jet nozzle. Specifically, the injection channel 7 has the ability to accelerate the shape of the reducing agent by reducing the flow area of ​​the reducing agent, i.e., the cross-sectional area through which the reducing agent flows as it enters the injector nozzle 4. The reducing agent 8 is guided from the nozzle inlet 16 through the injection channel 7 and is injected from the injector nozzle 4 into the exhaust gas stream 3 at the nozzle outlet 12. Thus, the reducing agent 8 flows through the nozzle housing 6 around the nozzle pin 5, i.e., the injection channel.

[0062] By employing the principle of jet nozzles, a wide and uniform distribution of the reducing agent in the exhaust gas stream 3 can be achieved. To this end, the reducing agent can be pumped into the nozzle inlet 16 at a high pressure of, for example, approximately 9 bar to 15 bar, to ensure uniform distribution of the reducing agent at the nozzle inlet 16 and the nozzle outlet 12.

[0063] Furthermore, the nozzle pin 5 is configured to move within the nozzle housing 6 to adjust the shape of the injection channel 7 according to various operating modes, thereby changing the injection parameters of the reducing agent injector 2 as described below.

[0064] For example, Figure 1 and Figure 2 Two operating modes of the exhaust gas aftertreatment system 10 are shown, namely, the first operating mode ( Figure 1 ) and second operating mode ( Figure 2 ). Figure 5 , Figure 7 and Figure 9 A detailed view of the injector nozzle 4 in the first operating mode is shown, while Figure 6 , Figure 8 and Figure 10 The injector nozzle 4 is shown in the second operating mode.

[0065] Hereinafter, the first operating mode is referred to as the "focused mode," and the second operating mode is referred to as the "defocused mode." In focused mode, the reducing agent 8 is injected at a negative reducing agent injection angle (α), which means that the reducing agent 8 flows towards the central axis of the exhaust pipe 1 and concentrates or contracts (see...). Figure 1 Conversely, in dispersion mode, the reducing agent is injected into exhaust pipe 1 at a positive reducing agent injection angle (α). The reducing agent injection angle (α) can be varied (see [link to relevant documentation]). Figure 2 ).

[0066] The two operating modes correspond to different positions of the nozzle pin 5 within the nozzle housing 6. In the first operating mode, the nozzle pin 5 moves inward toward the nozzle housing 6, meaning the reducing agent 8 moves downstream relative to the flow direction of the exhaust gas 3. In the second operating mode, compared to the first operating mode, the nozzle pin 5 moves outward toward the nozzle housing 6. The nozzle pin 5 and the nozzle housing 6 are configured such that when the nozzle pin 5 moves outward toward the nozzle housing 6, some portions of the injection channel 7 (…) Figure 6 The left side of the channel widens. The effect is that the flow behavior of the reducing agent within the injection channel 7 is relative to... Figure 5 The position of nozzle pin 5 has changed. Furthermore, the geometry of nozzle outlet 12 has also been adjusted. Figure 6 (Right side).

[0067] In the two operating modes, the flow behavior and injection parameters differ due to the different shapes and arrangements of the injection channel 7 and the nozzle outlet 12. Injection parameters, including the reducing agent injection angle (α), reducing agent flow velocity (v1-v3), and reducing agent flow type, can be varied according to the appropriate shapes of the outer surface 5a of the nozzle pin 5 and the inner surface 6a of the nozzle housing 6. Therefore, the injection process can be conveniently adjusted by simply moving the nozzle pin 5 within the nozzle housing 6. This can be performed during the operation of the exhaust aftertreatment system 10, i.e., during the operation of the vehicle 100.

[0068] To facilitate the movement of the nozzle pin 5, the reducing agent injector 2 further includes a nozzle actuator 14 configured to move the nozzle pin 5. In the embodiment described herein, the nozzle actuator is arranged along the central axis 13 of the exhaust pipe 1 and is upstream of the injector nozzle 4 relative to the exhaust gas flow 3 to avoid increasing the cross-sectional area and flow resistance of the reducing agent injector 2.

[0069] The illustrated embodiment of the injector nozzle 4 further includes a vortex chamber 9, which is formed as a recess within the nozzle housing 6 extending circumferentially along the inner surface 6a of the nozzle housing 6 in the axial direction surrounding the nozzle pin 5 (therefore, in this embodiment, the vortex chamber 9 is formed as annular). The vortex chamber 9 is used to further regulate the flow of the reducing agent 8 through the injection channel 7. For this purpose, the vortex chamber 9 is arranged between the inner diameter defined by the outer surface 5a of the nozzle pin 5 and the outer diameter defined by the inner surface 6a of the nozzle housing 6, guiding the reducing agent 8 at different flow velocities between the inner and outer diameters, thereby generating a flow vortex 11 in the reducing agent 8.

[0070] It should be understood that the illustrated embodiments are provided merely as examples, and those skilled in the art will readily conceive of vortex chambers with different shapes. Furthermore, more than one vortex chamber, for example, several annular vortex chambers arranged continuously along the axial direction, has significant advantages in certain applications. Moreover, the injection channel 7 can be divided into several separate channels, joined or unjoined, at the nozzle inlet 16 and / or nozzle outlet 12.

[0071] exist Figure 7 and Figure 9 The concentrated mode of the vortex chamber in this embodiment is shown in more detail. In the concentrated mode, the reducing agent 8 moves along the outer diameter through the vortex chamber (9) at a first velocity (v1), which is greater than the second velocity v2 of the reducing agent 8 moving along the inner diameter. The flow path corresponding to the inner diameter is shorter than the path along the outer diameter. When the different flow paths recombine at the end of the vortex chamber 9, the different velocities cause rotational behavior in the flow of reducing agent 8, thereby generating stable flow vortices 11 under certain conditions. These flow vortices 11 can then propagate along the injection channel 7 and be ejected from the nozzle outlet 12 (see [reference]). Figure 9 During the flow of reducing agent 8, the flow vortex 11 can expand (see...). Figure 9 The shape of the nozzle outlet 12 can be further used to define the flow vortex 11 and its concentration direction.

[0072] By moving the nozzle pin 5 relative to the nozzle housing 6, the vortex generation conditions can be altered. Therefore, the nozzle pin 5 can be moved to adjust various characteristics of the vortex, such as the vortex shape and / or vortex flow behavior of the generated flow vortex 11. This can be used to further adjust the injection process of the reducing agent 8.

[0073] exist Figure 2 , Figure 6 , Figure 8 and Figure 10In the dispersed mode, because the velocity (v1-v3) difference in the vortex chamber 9 is insufficient to induce a stable flow vortex 11, the reducing agent 8 will not generate a stable vortex. Although vortices can be generated, they are unstable and eventually decay. However, the flow of the reducing agent 8 may still be turbulent. By gradually moving the nozzle pin 5 within the nozzle housing 6 and altering the behavior of the flow vortex 11 according to the appropriate shapes of the inner surface 6a of the nozzle housing 6 and the outer surface 5a of the nozzle pin 5, the flow vortex 11 can be transformed from a "clear" and stable vortex into a normal turbulent flow with vortices that are unstable even in laminar flow.

[0074] In concentrated mode, the appropriate shape of the nozzle outlet 12 can be used to adjust the impact point / concentration point of the reducing agent 8 within the exhaust pipe 1. Generally, also in dispersed mode, the nozzle outlet 12 can be used to adjust the reducing agent injection angle (α). Typically, the reducing agent injection angle (α) is a function of the diameter of the exhaust pipe 1, the flow velocity of the exhaust gas 3, the shape of the nozzle outlet 12, and the flow behavior of the reducing agent 8 within the injection channel 7, which in turn depends on the velocity difference between different flow paths within the injection channel 7.

[0075] Therefore, this invention provides a reducing agent injector based on the jet principle, which achieves uniform expansion of the reducing agent injected across the cross-section of the exhaust pipe and the SCR device, thereby effectively improving the SCR performance compared to conventional systems. The system can use a single nozzle at the center location where the cross-sectional area is smallest, thus minimizing flow resistance. However, in other embodiments, multiple injector nozzles composed of jet nozzles can also be used.

[0076] Furthermore, this system utilizes the vortex principle within the jet nozzle to enhance control over injection parameters. Thus, by actively moving the nozzle pin during operation, the nozzle design can be adjusted to different application areas (e.g., different pipe diameters or different motor sizes) and different operating points.

[0077] Figure 3 The corresponding exhaust gas aftertreatment method M is schematically shown. The exhaust gas aftertreatment method M includes step M0, in which the nozzle pin (5) is moved within the nozzle housing (6) to adjust the shape of the injection channel (7) according to the operating mode, thereby adjusting the injection parameters of the reducing agent injector 2. The exhaust gas aftertreatment method (M) further includes step M1, in which the reducing agent 8 is injected through the injector nozzle 4 of the reducing agent injector 2 into the exhaust gas flow 3 guided through the exhaust pipe 1. Here, the reducing agent 8 is accelerated through the injection channel 7 and discharged into the exhaust gas flow 3. The reducing agent 8 is guided through the vortex chamber 9 within the injection channel 7 at different flow velocities between the inner diameter defined by the outer surface 5a of the nozzle pin 5 and the outer diameter defined by the inner surface 6a of the nozzle housing 6, thereby generating a flow vortex 11 in the reducing agent 8.

[0078] In the detailed description above, various features have been grouped into more than one example for the purpose of simplifying the invention. It should be understood that the above description is illustrative and not restrictive. It is intended to cover all alternatives, variations, and equivalents of different features and embodiments. Various other examples will be apparent to those skilled in the art from the above description. The embodiments were chosen and described to explain the principles of the invention and its practical application, thereby enabling others skilled in the art to utilize various modified embodiments suitable for the invention and specific uses conceivable.

Claims

1. An exhaust gas aftertreatment system (10) comprising: an exhaust pipe (1) for guiding an exhaust gas flow (3); and a reductant injector (2) configured to protrude into the exhaust pipe (1) and to inject a reductant (8) into the exhaust gas flow (3) through an injector nozzle (4), the injector nozzle (4) comprising a nozzle pin (5) arranged within a nozzle housing (6) such that a jet channel (7) is formed between an outer side surface (5a) of the nozzle pin (5) and an inner side surface (6a) of the nozzle housing (6), the reductant (8) being discharged through the jet channel (7) into the exhaust gas flow (3), the jet channel (7) being formed such that the reductant is accelerated, wherein the jet channel (7) comprises a swirl chamber (9) formed between an inner diameter defined by the outer side surface (5a) of the nozzle pin (5) and an outer diameter defined by the inner side surface (6a) of the nozzle housing (6), the swirl chamber (9) being formed to guide the reductant (8) between the inner diameter and the outer diameter at different flow velocities, thereby generating flow swirls (11) in the reductant (8), wherein the swirl chamber (9) is formed as a recess within the nozzle housing (6) extending circumferentially along the inner side surface (6a) of the nozzle housing (6) around an axial direction of the nozzle pin (5), wherein the injector 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), wherein the different flow swirls (11) propagate along the jet channel (7) after recombining at an end of the swirl chamber (9) and are ejected from a nozzle outlet (12), the flow swirls (11) uniformly expanding during the flow of the reductant (8), the reductant injector (2) further comprising a nozzle actuator (14) configured to move the nozzle pin (5), wherein the nozzle actuator (14) is arranged along the central axis (13) of the exhaust pipe (1) and is oriented upstream with respect to the exhaust gas flow (3) compared to the injector nozzle (4) to form a minimum cross section, wherein several annular swirl chambers are arranged in axial succession.

2. The exhaust gas aftertreatment system (10) according to claim 1, wherein the nozzle pin (5) is configured to be movable within the nozzle housing (6) to adjust a shape of the jet channel (7) and thereby an injection parameter of the reductant injector (2) depending on an operating mode.

3. The exhaust gas aftertreatment system (10) according to claim 2, wherein the injection parameter comprises at least one of a reductant injection angle (a), a reductant flow velocity (vi-v3) and a reductant flow type.

4. The exhaust gas aftertreatment system (10) according to claim 1, wherein the nozzle pin (5) is configured to adjust a shape of the swirl chamber (9) by moving within the nozzle housing (6) and thereby adjust a swirl shape and / or a swirl flow behavior of the generated flow swirls (11).

5. The exhaust gas aftertreatment system (10) according to any one of claims 1 to 3, wherein ​ The nozzle pin (5) is configured to adjust the shape of the nozzle outlet (12) of the injector nozzle (4) by moving the nozzle pin (5) within the nozzle housing (6).

6. A vehicle (100), comprising: - an internal combustion engine (101); and and The exhaust gas aftertreatment system (10) according to claim 1.

7. An exhaust gas aftertreatment method (M), comprising the steps of: injecting a reducing agent (8) into an exhaust gas stream (3) guided through an exhaust pipe (1) through an injector nozzle (4) of a reducing agent injector (2) (M1), accelerating the reducing agent (8) through an injection channel (7) and discharging it into the exhaust gas stream (3), the injection channel (7) being formed between an inner side surface (6a) of a nozzle housing (6) of the reducing agent injector (2) and an outer side surface (5a) of a nozzle pin (5) of the reducing agent injector (2) arranged within the nozzle housing (6), wherein the reducing agent (8) is guided through a swirl chamber (9) within the injection channel (7) at different flow velocities between an inner diameter defined by the outer side surface (5a) of the nozzle pin (5) and an outer diameter defined by the inner side surface (6a) of the nozzle housing (6), thereby generating flow swirls (11) in the reducing agent (8), wherein the swirl chamber (9) is formed as a recess within the nozzle housing (6) extending circumferentially along the inner side surface (6a) of the nozzle housing (6) around an axial direction of the nozzle pin (5), wherein the injector nozzle (4) is arranged along a central axis (13) of the exhaust pipe (1) and downstream with respect to the exhaust gas stream (3), wherein the different flow swirls (11) propagate along the injection channel (7) after recombining at the end of the swirl chamber (9) and are injected from a nozzle outlet (12), the flow swirls (11) expanding uniformly during the flow of the reducing agent (8), the reducing agent injector (2) comprising a nozzle actuator (14) configured to move the nozzle pin (5), wherein the nozzle actuator (14) is arranged along the central axis (13) of the exhaust pipe (1) upstream with respect to the exhaust gas stream (3) compared to the injector nozzle (4) to form a minimum cross section, wherein several annular swirl chambers are arranged in axial succession.

8. The exhaust gas aftertreatment method (M) according to claim 7, further comprising the step of: moving the nozzle pin (5) within the nozzle housing (6) to adjust the shape of the injection channel (7) and thereby the injection parameters of the reducing agent injector (2) depending on an operating mode (M0).

9. The exhaust gas aftertreatment method (M) according to claim 7, wherein the shape of the swirl chamber (9) is adjusted by moving the nozzle pin (5) within the nozzle housing (6) to adjust the swirl shape and / or the swirl flow behavior of the generated flow swirls (11).

10. The exhaust gas aftertreatment method (M) according to claim 7 or 8, wherein the shape of the nozzle outlet (12) of the injector nozzle (4) is adjusted by moving the nozzle pin (5) within the nozzle housing (6).

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