Chamber mixer for automotive exhaust aftertreatment systems

Abstract

The present invention relates to a chamber mixer (10) for an exhaust aftertreatment system of an automotive vehicle, the chamber mixer (10) having an internal volume (18) of the chamber mixer in a throughflow direction (26), the internal volume being bounded by a housing (16) having at least one housing side that is double-walled and has an outer wall (30) and an inner wall (32) that divides the internal volume (18) into an inner chamber (34) and an outer chamber (36), and the first fluid (12) can flow through an inlet opening (22). The fluid being passed through can be separated into a main flow (38) flowing through the inner chamber (34) and a secondary flow (40) flowing through the outer chamber (36), and the main flow (38) can be acted upon by a flow device (48) having a double swirl (50) and a fluid introduction device (56) having an introduction end (58) that is disposed within the outer chamber (36) and through which a second fluid (14) can be injected into the inner chamber (34) through an introduction opening (60) in the inner wall (32).

Description

[Technical field]

[0001] The invention relates to a chamber mixer for an exhaust aftertreatment system of a motor vehicle according to claim 1. [Background technology]

[0002] Exhaust aftertreatment systems are used to purify the combustion gases of an internal combustion engine of a motor vehicle. In particular, the motor vehicle may be a car or a truck. The internal combustion engine may be designed as a diesel engine. Its combustion gases or exhaust gases usually contain nitrogen oxides such as nitric oxide and nitrogen dioxide. During exhaust aftertreatment of a diesel engine, selective catalytic reduction is used in particular to reduce the nitrogen oxides. For this purpose, a reducing agent such as a urea solution is injected as a second fluid into the exhaust gas, which represents a first fluid. The first and second fluids mix with each other and flow into the SCR catalytic converter. The urea solution decomposes in the exhaust gas into ammonia and water. A reaction takes place in the SCR catalytic converter, the products of which are water and nitrogen.

[0003] US Patent No. 10,024,217 and US Patent No. 10,408,110 both show a chamber mixer. A reducing agent is added to the exhaust gas in the chamber mixer and mixed. Furthermore, Chinese Patent No. 110,337,324 shows another chamber mixer for an aftertreatment system. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] U.S. Pat. No. 10,024,217 [Patent Document 2] U.S. Patent No. 10,408,110 [Patent Document 3] Chinese Patent No. 110,337,324 Summary of the Invention

[0005] The object of the invention is to provide a chamber mixer for an exhaust aftertreatment system of a motor vehicle which is particularly compact and furthermore allows particularly good mixing of exhaust gas and reducing agent for a high efficiency of exhaust aftertreatment.

[0006] This object is achieved by the subject matter of the independent patent claims. Advantageous and advantageous embodiments of the invention are the subject matter of the dependent patent claims, the description and the drawings.

[0007] The chamber mixer according to the invention is provided for an exhaust aftertreatment system of a motor vehicle, which is used for exhaust aftertreatment of an internal combustion engine, in particular a diesel engine, and the motor vehicle can be, for example, a car or a truck.

[0008] The chamber mixer has an internal volume delimited by a housing. A first fluid can flow through the internal volume from an inlet opening arranged on or in the housing at one end of the internal volume along the through-flow direction to an outlet opening arranged on or in the housing at the other end of the internal volume. In the chamber mixer according to the invention, at least the second housing side is double-walled with an outer wall and an inner wall, dividing the internal volume into an inner chamber and an outer chamber located between the inner and outer walls. Furthermore, in particular due to the design of the inlet opening, the first fluid flowing through the inlet opening, in particular in gaseous form, can be divided into a main flow flowing through the inner chamber and an auxiliary flow flowing through the outer chamber. Furthermore, in accordance with the invention, a flow device is provided in which the main flow can undergo a double swirl, in particular a symmetrical double swirl, in the through-flow direction. Furthermore, the chamber mixer comprises a fluid introduction device with an introduction end arranged in the outer chamber and therefore able to flow around, in particular by an auxiliary flow. A second liquid, in particular a liquid fluid such as a reducing agent, can be injected into the inner chamber at the introduction end via the introduction end or via an introduction opening in the inner wall. Furthermore, downstream in the throughflow direction a merging device can be provided, through which the main and auxiliary flows can be guided into one another, in particular before reaching the outlet opening.

[0009] "Arranged at one end of the internal volume" is to be understood in particular as "arranged upstream in the direction of flow". "Arranged at the other end of the internal volume" means in particular "arranged downstream". Thus, in particular, the outlet opening is arranged downstream in the direction of flow on the chamber mixer or on the internal volume formed by the inner and outer chambers.

[0010] In other words, a chamber mixer according to the invention is presented which can be designed as a decomposition reactor, which has a flow device in the inlet opening, where the fluid flow is split into two parts or two partial main flows when passing through the flow device. In particular, the main flow is converted into a bidirectional flow by the double swirl plate of the flow device. The auxiliary flow passes between the inner and outer walls, in particular around the area near the inlet end of the fluid introduction device. At the downstream end of both the inner and outer chambers, the main and auxiliary flows converge again and can exit the chamber mixer via the outlet opening.

[0011] For example, the design of the inner chamber and / or inner wall in the form of a deflection element of the flow device displaces the main flow or supports a symmetric double turn along the throughflow direction.

[0012] The effect of the double swirl on the main flow means that two partial flows can or are formed along the throughflow direction as two vortices of the first fluid flowing side by side. Their respective rotation axes are essentially oriented along the throughflow direction. The two vortices describing the double swirl are formed by the flow device, in particular at one end, each extending in particular along the longitudinal extension direction of the chamber mixer, which essentially coincides with the throughflow direction. The respective vortices located within the respective air vortex or the fluid of the first fluid move along the throughflow direction and also move essentially circularly around their respective rotation axes, thus essentially describing a helical path. The two vortices each have a different direction of rotation, so that one rotates clockwise and the other counterclockwise.

[0013] The introduced second fluid, in particular a liquid fluid, evaporates into the gas phase in this double swirl formed in the main flow, whereby the evaporation can be advantageously improved by injection using the fluid introduction device and / or by, for example, applying heat. The second fluid can in particular be a reducing agent, whereby the fluid introduction end can therefore introduce the reducing agent into the internal volume, in particular by injection. The first fluid, in particular in the form of exhaust gases, which may contain nitrogen oxides due to the combustion of diesel fuel, can be mixed with the reducing agent in the chamber mixer, whereby the mixture of the first and second fluids can be reacted in the SCR catalytic converter.

[0014] For example, when urea is used as a reactant, a pyrolysis and subsequent hydrolysis reaction can take place in the chamber mixer, whereby ammonia is released from the urea to neutralize the nitrogen oxides. The pyrolysis and hydrolysis take place in the interior volume, particularly on a path along the chamber mixer in the throughflow direction.

[0015] One advantage of the chamber mixer according to the invention is that no complex mixer design is required for atomizing and / or vaporizing the second fluid. In this way, the mixing and vaporization, and thus the atomization, of the second fluid can be achieved in a particularly advantageous manner by the chamber mixer according to the invention. It is therefore also possible to design the chamber mixer particularly compact and / or with few components.

[0016] Due to the double swirl, a particularly advantageous mixing between the first and second fluid takes place here, whereby exhaust aftertreatment can be carried out in a particularly advantageous manner.

[0017] Thus, the chamber mixer can be used to advantageously bring the injected liquid reducing agent - the second fluid - into contact with the exhaust gas, i.e. the first fluid. The chamber mixer according to the invention has the advantage that a particularly high mixing uniformity of the two fluids can be achieved. As a result of this mixing uniformity, the catalytic reduction of the exhaust gas (first fluid), in particular of the nitrogen oxides contained therein, can also be carried out in a particularly advantageous manner. Furthermore, the chamber mixer is designed in such a way that a particularly low counter pressure against the direction of flow of the first fluid is expected. Another advantage is that due to the division into a main and an auxiliary flow and the application of a double swirl to the main flow, the growth of deposits on the walls or housing of the chamber mixer can be avoided or is at least particularly low.

[0018] In an advantageous embodiment of the invention, the flow device comprises a double swirl plate arranged in or at the first partial inlet opening of the inlet opening. In other words, an element influencing the flow of the incoming first fluid, i.e. exhaust gas, is provided, the double swirl plate of the flow device, whose task is to influence the flow in such a way that the application of double swirl to the main flow according to the invention can take place in a particularly advantageous manner. The double swirl plate at least partially closes the inlet opening, whereby the lamella represents an obstacle to the flow of the first fluid. In order to achieve a symmetric double swirl, the orientation of the lamella with respect to the inlet opening is also symmetric. This brings the advantage that it is particularly easy to influence the incoming exhaust gas or first fluid to generate a double swirl.

[0019] In another advantageous embodiment of the invention, the flow device has at least one deflection element arranged in the inner chamber and / or on the inner wall. Additionally or alternatively, at least a part of the inner wall is designed as a deflection element. In particular, the deflection element has an advantageous shape for forming a double swirl or for reinforcing the double swirl and / or for maintaining the double swirl. The deflection element can therefore also represent an obstacle to the flow of the first fluid. In other words, the flow device comprises a deflection element arranged in the inner chamber to convey the double swirl of the main flow, preferably formed on and / or through the inner wall. In this way, the deflection element can be, for example, a curvature of the inner wall with a radius of double swirl, whereby the first fluid or the exhaust gas flowing towards the deflection element can flow along the inner wall and thus form a part of the double swirl or a vortex. This gives the advantage that the flow device can be used particularly advantageously to generate, amplify and / or maintain the double swirl of the main flow.

[0020] In a further advantageous embodiment of the invention, the merging device has at least one through-hole opening in the part of the inner wall that is assigned to the outlet opening. In other words, the downstream part of the inner wall is provided with a through-hole opening through which, for example, the first fluid of the auxiliary flow can flow in order to merge with the main flow. Thereby, the inner wall is designed, for example, as a perforated metal sheet, in particular with a wing bead. This has the advantage that the auxiliary flow can be merged with the main flow or they can be guided against each other in a particularly simple and therefore fail-safe manner. This allows, in particular, the auxiliary flow to be guided into the main flow.

[0021] In a further advantageous embodiment of the invention, a heating device is provided which can heat the inner wall and / or at least one further inner wall at least in a respective sub-region in order to vaporize the second fluid. In other words, at least a part of the wall delimiting the inner chamber can be heated or warmed, thereby at least supporting the vaporization of the second fluid introduced into the internal volume by the fluid introduction device. This provides the advantage that the mixing of the first and second fluids and thus the efficiency of the exhaust aftertreatment can be improved in a particularly advantageous manner.

[0022] In a further advantageous embodiment of the invention, the fluid introduction device is designed to inject a urea solution, in particular an aqueous urea solution. In other words, a urea solution that can be conveyed or injected into the internal volume by the fluid introduction device is advantageously used as the second fluid. In other words, an embodiment of the fluid introduction device, which can in particular have a nozzle, in particular its introduction end, is adapted to convey and inject the urea solution. For this purpose, for example, the nozzle, the line and / or the at least one pump of the fluid introduction device can be adapted to the viscosity of the urea solution in order to operate in a particularly advantageous manner. This provides the advantage that the chamber mixer can be used particularly advantageously for exhaust aftertreatment.

[0023] In a further advantageous embodiment of the invention, beading is incorporated into the inner wall, which is oriented in the throughflow direction so as to promote the mixing of the second fluid with the first fluid. If the inner wall is preferably a metal sheet, it can be embossed with beading. This brings the advantage that the mixing of the second fluid with the first fluid can be improved in a particularly simple and / or cost-effective manner in addition to the double swirl, since for example the injected second fluid can be particularly well introduced into the main flow colliding with the double swirl when it hits the beading.

[0024] In a further advantageous embodiment of the invention, the chamber contour or the chamber cross section of the inner chamber tapers downstream, which promotes mixing of the first and second fluids, which has the advantage that mixing of the first and second fluids, and thus exhaust aftertreatment, can be performed particularly efficiently.

[0025] Furthermore, the chamber walls of the inner chamber, i.e. the inner wall and / or the at least one further inner wall, advantageously have no edges and / or obstacles, so that a particularly low back pressure can be achieved when the main flow, and in particular also the auxiliary flow, flows through the chamber, for example in the flow direction.

[0026] In a further advantageous embodiment of the invention, the inlet opening and the outlet opening are arranged on one side of the housing, in other words the two openings face towards the same side of the housing, which has the advantage that the housing can be designed particularly compactly.

[0027] Further advantages, features and details of the invention are evident from the following description of preferred embodiments and the drawings. Without departing from the scope of the invention, the features and combinations of features mentioned above in the description, as well as the features and combinations of features mentioned below in the description of the drawings and / or the features and combinations shown alone in the drawings, can be used not only in the combinations shown in each case, but also in other combinations or alone.

[0028] The drawings show: [Brief description of the drawings]

[0029] [Figure 1] 1 is a schematic perspective view of a chamber mixer for an exhaust aftertreatment system of an automotive vehicle; [Diagram 2] FIG. 2 is a schematic top view of the chamber mixer according to FIG. 1; [Diagram 3] FIG. 2 is a side cross-sectional view of the chamber mixer according to the previous figures. [Figure 4]FIG. 2 is a cross-sectional front view of the chamber mixer according to the previous figures. [Diagram 5] FIG. 2 is a schematic side view of the chamber mixer according to the previous figures. [Figure 6] FIG. 2 is a cross-sectional top view of the chamber mixer according to the previous figure. [Figure 7] 13 is a further cross-sectional side view of another embodiment of the chamber mixer. [Figure 8] FIG. 8 is a schematic top view of the inner wall and double pivot plate of the chamber mixer according to FIG. [Figure 9] FIG. 8 is a schematic front cross-sectional view of the chamber mixer according to FIG. 7. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0030] 1 shows a schematic perspective view of a chamber mixer 10 for an exhaust aftertreatment system of an automotive vehicle. The exhaust aftertreatment system is used for exhaust aftertreatment to purify combustion gases from an internal combustion engine of the automotive vehicle. In this way, emissions can be reduced during use of the automotive vehicle, which may be a car or truck, among others.

[0031] In particular, if the internal combustion engine is a diesel engine, the exhaust aftertreatment system can operate on the basis of selective catalytic reduction. The exhaust aftertreatment can thus reduce, in at least one SCR catalytic converter, the nitrogen oxides, in particular nitric oxide and nitrogen dioxide, from the exhaust gases that can flow through the chamber mixer 10 as the first fluid 58. The exhaust aftertreatment in the chamber mixer 10 is advantageously started by contacting the exhaust gases, i.e. the first fluid 58, with a reducing agent that is injected into the chamber mixer 10 as the second fluid 38. The mixture of the first and second fluids flows from the chamber mixer 10 into the at least one SCR catalytic converter, in which a selective catalytic reaction, known per se, then takes place.

[0032] Prior art has shown that poor mixing uniformity between the fluids results in low exhaust aftertreatment value or the use of chamber mixers in which the fluids can only flow at high counter pressure, which promotes the growth of deposits and therefore deposition from the fluids in the previous chamber mixer.

[0033] These shortcomings of the prior art are avoided by the chamber mixer 10 according to the present invention as shown.

[0034] For this purpose, the chamber mixer 10 has an internal volume 14 bounded by a housing 12. As indicated by a first arrow P1 shown in FIG. 1, a first fluid 58 flows into the internal volume 14 through an inlet opening 18 arranged at one end of the internal volume 14 on the first housing side 16. Together with the mixed second fluid 38, the first fluid 58 flows through the internal volume 14 along a throughflow direction 22 to an outlet opening 20 arranged at the other end of the (same) first housing side 16 of the internal volume 14 and exits from the outlet opening 20 to the outside of the internal volume 14 and thus from the housing 12 of the chamber mixer 10, as indicated by a second arrow P2.

[0035] In the chamber mixer 10, at least the second housing side 80 of the housing 58 is double-walled with the outer wall 24 and the inner wall 26 shown in Figures 3, 4, 6, 7 and 9, dividing the interior volume 14 into an inner chamber 28 and an outer chamber 30 located between the inner wall 26 and the outer wall 24, which is visible for example in Figure 3. The second housing side 80 of the housing 12 is preferably designed opposite the inlet opening 18 and the outlet opening 20.

[0036] The chamber mixer 10 is further designed in such a way that a first fluid 58 - exhaust gas of the internal combustion engine - entering, in particular in gaseous form, through the inlet opening 18 can be or is in particular divided through the inlet opening 18 into a main flow 54 flowing through the inner chamber 28 and an auxiliary flow 56 flowing through the outer chamber 30. For this purpose, the inlet opening 18 has a first partial inlet opening 42 for the inner chamber 28 with its main flow 54 and a second partial inlet opening 62 for the outer chamber 30 with its auxiliary flow 56. When the first fluid 58 enters the housing 12 through the inlet opening 14 and the first and second partial inlet openings 60 and 62, the first fluid 58 is diverted in the through-flow direction 22 into the main flow 54 and the auxiliary flow 56, respectively. The outer chamber 30 firstly extends along a third housing side starting from the inlet opening 18 and merging at an angle with the second housing side 80.

[0037] Furthermore, a flow device 32 is provided, by means of which the main flow 54 can undergo a double swirl 70, in particular a symmetrical double swirl, in the throughflow direction 22. This means that, when the first fluid 58 flows downstream through the inner chamber 28 transversely to the throughflow direction 22, it is divided downstream of the first partial inlet opening 42 in the inner chamber 28 into a first partial main flow 66 which swirls clockwise of the main flow 54 and a second partial main flow 68 which swirls counterclockwise. In each of the two partial main flows 66 and 68, the first fluid 58 or the mixed fluid of the first and second fluids 58 and 38 essentially moves in a spiral as it flows through the inner chamber 28.

[0038] Also provided on the third housing side is a fluid introduction device 34 with an introduction end 36. The introduction end 36 is arranged in the outer chamber 30 and can therefore flow around by the auxiliary flow 56. A second fluid 38, in particular a liquid fluid - a reducing agent such as a urea solution - can be injected into the inner chamber 28 through the introduction opening 40 of the inner wall 26 via the fluid introduction device 34. Furthermore, downstream in the throughflow direction 22, a merging device 42 is provided, by means of which the main flow 54 and the auxiliary flow 56 with two partial main flows 66 and 68 can be guided to each other and thus mixed with each other. The merging device 42 is essentially provided upstream of the outlet opening 20 in the internal volume 14. The mixed fluids 58 and 38 are deflected in the internal volume 14 in the region of the merging device 42 at the fourth housing wall 64 and then flow out of the outlet opening 20 of the housing 12 and thus out of the chamber mixer 10. The flow confluence device 42 has at least one through-hole opening 48 through which the auxiliary flow 56 enters the inner chamber 28. Thus, the fourth housing wall 64 extends from the second housing side 80 to the outlet opening 20.

[0039] FIG. 2 shows a schematic top view of the chamber mixer 10 according to FIG. 1, and is particularly useful for illustrating the portions shown in FIGS. 3 and 4 along lines A1-A1 and A2-A2.

[0040] Thus, Fig. 3 shows the chamber mixer 10 according to the two aforementioned figures in a schematic cross-sectional side view along the line A1-A1, whereby the two chambers formed from the internal volume 14, the inner chamber 28 and the outer chamber 30 are particularly advantageously recognizable here. According to Fig. 3, the through-flow direction 22 essentially extends along the longitudinal extension direction of the chamber mixer 10, whereby the respective fluids 58 and 38 can deviate from the longitudinal extension direction of the chamber mixer 10 in the respective transverse extension direction, in particular in the vicinity of the inlet opening 18 and the outlet opening 20. In the illustrated embodiment, the first fluid 58 is deflected downstream of the inlet opening 18 by an angle of about 90 ° in the through-flow direction 22, and the first fluid 58 and the second fluid 38 mixed with the first fluid 58 are also deflected upstream of the outlet opening 20 by an angle of 90 ° to the through-flow direction 22. It goes without saying that deflection angles are also possible. The mixed first fluid 58 and second fluid 38 exit the chamber mixer 10 through the exit opening 20 as a mixed fluid.

[0041] For example, the flow device 32 may include a double swirl plate 44 arranged at the first partial inlet opening 60 of the inlet opening 18. In the first embodiment according to Figs. 1 to 6, the double swirl plate 44 has a plurality of lamellae 72 oriented in the longitudinal or throughflow direction 22 and configured to correspondingly generate a clockwise swirl of a first partial main flow 66 and a counterclockwise swirl of a second partial main flow 68 with respect to the first fluid 58 flowing towards the inlet opening 18. The first fluid 58 enters the chamber mixer 10 through the openings 50 between the lamellae 72 and is deflected there accordingly. The second partial inlet opening 62 is free of flow devices. Furthermore, as shown in the schematic front cross-sectional view of Fig. 4 along A2-A2, the flow device 32 may have at least one deflection element 46 arranged in the inner chamber 28 and / or on the inner wall 26. The deflection element 46 is used in particular to apply a double swirl 70 to the main flow 54 or to reinforce or maintain it, and can also be guided downstream towards the outlet opening 20. The deflection element 46 has an essentially triangular cross section, with one edge 78 of the deflection element 46 facing the inlet opening 18. The edge 78 of the deflection element 46 starts essentially in the central region of the inlet opening 18 and extends in the internal volume 14 to the outlet opening 20. The deflection element 46 is formed by a recess 76 of a second housing side 80 which leads into the essentially triangular cross section of the inner wall 26 and which projects into the internal volume 14. In particular in Figures 3 and 4 it can be seen that the outer wall 24 also has a triangular cross section, and therefore also the outer chamber 30, in the region of the edge 78.

[0042] FIG. 5 shows a schematic side view of the chamber mixer 10, marking the cross section A3-A3 shown in FIG.

[0043] FIG. 6 shows a schematic top view of the chamber mixer 10. The inclined lamella 72 of the double-swivel plate 44 is particularly clearly visible, as is the web 74 of the double-swivel plate 44, which is arranged centrally between the lamella 72. The web 74 ensures an improved stability of the double-swivel plate 44. Between the web 74 and the lamella 72, there are also openings 50 to the left and right of it. Furthermore, it can be seen that, in contrast to the first partial inlet opening 60 with the double-swivel plate 44, the second partial inlet opening 62 has no flow device, and the first fluid 58 can flow into the outer chamber 30 without being deflected. In particular, as from FIG. 2, as can also be seen from FIG. 6, the internal volume 14 of the chamber mixer 10 has a cross section that decreases along the throughflow direction 22 from the inlet opening 18 to the outlet opening 20. Overall, the housing 12, and therefore the internal volume 14, tapers from the inlet opening 18 towards the outlet opening 20, such that the velocities of the first fluid 58 and the second fluid 38 increase within the internal volume 14 of the chamber mixer 10 from the inlet opening 18 towards the outlet opening 20, thereby achieving improved mixing of the first fluid 58 and the second fluid 38.

[0044] 7 to 9 show a further embodiment of the chamber mixer 10, in which FIG. 7 shows the chamber mixer 10 in a cross-sectional view similar to that of FIG. 3. Identical components or components with the same effect are provided with the same reference numbers as in the embodiment shown in FIGS. 1 to 6. FIG. 7 shows how the second fluid 38 can be introduced into the inner chamber 28 by the fluid introduction device 34 through the introduction opening 40 via the introduction end 36. In particular, the introduction can be carried out in liquid form so that the liquid second fluid 38 can come into contact with the inner wall 26. In order for the second fluid 38 to be advantageously used for exhaust aftertreatment, it should advantageously mix with the first fluid 58 - exhaust gas - in the gas phase in the double swirl 70. For this purpose, a heating device, not shown in more detail, can be advantageously provided which heats the inner wall 26 at least in a small area 64, in particular in the area where the second fluid 38 comes into contact with the inner wall 26, whereby the evaporation of the second fluid 38 and thus the transition from the liquid to the gas phase is at least promoted.

[0045] 7 also shows beading 52 formed on the inner wall 26. The beading 52 is oriented essentially transverse to the flow-through direction 22 to promote mixing of the first fluid 58 and the second fluid 38. This is because, for example, in addition to the double swirl 70, turbulence can be formed in the fluid or mixture of the first and second fluids 58 and 38 at the beading 52 within the inner chamber 34.

[0046] The fluid introduction device 34 is advantageously designed to inject a second fluid 38, in particular an aqueous urea solution. The urea solution can be converted into ammonia in a chemical reaction in the chamber mixer 10, so that the ammonia can advantageously bind or neutralize the nitrogen oxides in the exhaust gas in the SCR catalytic converter downstream of the chamber mixer 10. Furthermore, the merging device 42 has a number of through-hole openings 48 so that the first fluid 58 can enter the inner chamber 34 from the outer chamber 30 through the through-hole openings 48 and mix with the first and second fluids 58 and 38 in the inner chamber 34, thereby further improving the mixing of the first and second fluids 58 and 38.

[0047] 8 shows a schematic top view of the double pivot plate 44 in the second embodiment according to FIGS. 7 to 9 at a first partial inlet opening 60 of the inlet opening 18, which in the viewing direction of the figure is arranged above the inner wall 26 in which the through-hole openings 48 are provided. Thereby, in particular, a single opening 50 can be seen here, which tapers downstream in the through-flow direction 22 towards the outlet opening 20 and is arranged symmetrically transversely thereto in the alternative flow arrangement.

[0048] Figure 9 shows the cross section A4-A4, the position of which in the chamber mixer 10 is shown in Figure 7, with the arrows indicating the first and second partial main flows 66, 68 of the first fluid 58 and the double swirl 70 of the fluid mixture, respectively. To advantageously maintain or increase the double swirl 70 or to promote mixing of the first fluid 58 with the second fluid 38, the cross section of the inner chamber 28 may be smaller, particularly downstream. This may, for example, allow at least the inner chamber 28 to be tapered downstream.

[0049] The first partial main flow 66 and the second partial main flow 68 of the double swirl 70 of the first fluid 58 or fluid mixture are generated by the lamellae 72 in the opening 50 of the double swirl plate 44 that are bent inwards towards the inner chamber 28 and the inner wall 26 that has a concave shape at least at its edges. As shown in the cross section A4-A4, the two lamellae 72 of the opening 50 do not extend all the way into the inner chamber 34 as in the direction of the outlet opening 20 of the chamber mixer 10, as can be seen in FIG.

[0050] Through the chamber mixer 10 shown in the figure it is possible in a particularly advantageous manner to contribute to the exhaust aftertreatment by means of an exhaust aftertreatment system.

[0051] This leads to several advantages. For example, the chamber mixer 10 can be designed to be particularly compact, with a particularly small installation volume. Furthermore, further openings and / or holes can be omitted as blockage points, which can reduce, for example, the deposition growth of the urea solution on the surfaces of the housing 12 in contact with the inner chamber 28 and the outer chamber 30. Furthermore, the overall robustness of the chamber mixer 10 can be increased, for example, by eliminating the need for additional mixing devices in the internal volume 14. Furthermore, the internal volume can be formed essentially without edges and / or obstacles, which allows a particularly low back pressure when flowing in the throughflow direction 22. The chamber mixer 10 shown here therefore leads to a particularly advantageous exhaust aftertreatment. [Explanation of symbols]

[0052] 10 Chamber Mixer 12. Housing 14 Internal volume 16 Housing side 18 Inlet opening 20 outlet opening 22 Through flow direction 24 Exterior Wall 26 Inner wall 28 Inner Chamber 30 Outer Chamber 32 Flow Device 34 Fluid introduction device 36 Introductory end 38 Second Fluid 40 Introduction opening 42 Merging device 44 Double Swivel Plate 46 Deflection element 48 Through-hole opening 50 Opening 52 Beading 54 Main stream 56 Auxiliary flow 58 First Fluid 60 first partial inlet opening 62 Second partial inlet opening 64 small area 66 First partial main stream 68 Second partial main stream 70 Double Swivel 72 Lamella 74 Web 76 Recess 78 Edge 80 Second housing side P1 Arrow P2 Arrow

Claims

1. A chamber mixer (10) for an exhaust aftertreatment system of a motor vehicle, wherein a first fluid (58) can flow in a throughflow direction (22) through an internal volume (14) bounded by a housing (12) from an inlet opening (18) located at one end of the internal volume (14) within the housing (12) to an outlet opening (20) located at the other end of the internal volume (14) within the housing (12), at least a second housing side (80) of the housing (12) being of a double-wall design having an outer wall (24) and an inner wall (26) that divides the internal volume (14) into an inner chamber (28) and an outer chamber (30) located between the inner wall (26) and the outer wall (24), and wherein a first fluid (58) can flow through the inlet opening (18). a flow device (32) for subjecting the main flow (54) to a double swirl (70) in the throughflow direction (22); a fluid introduction device (34) having an introduction end (36) disposed within the outer chamber (30) through which a second fluid (38) can be injected into the inner chamber (28) through an introduction opening (40) in the inner wall (26); and a confluence device (42) disposed downstream in the direction of flow (22) for guiding the main flow (54) and the auxiliary flow (56) to each other.

2. 2. The chamber mixer (10) of claim 1, wherein the flow device (32) comprises a double swivel plate (44) disposed in a first partial inlet opening (60) of the inlet opening (18).

3. 3. The chamber mixer (10) according to claim 1 or 2, characterized in that the flow device (32) has at least one deflection element (46) arranged in the inner chamber (28) and / or on the inner wall (26), and / or at least a part of the inner wall (26) is designed as a deflection element (6).

4. 4. The chamber mixer (10) according to claim 1, wherein the confluence device (42) comprises at least one through-hole opening (48) in a portion of the inner wall (26) associated with the outlet opening (20).

5. 5. The chamber mixer (10) according to claim 1, further comprising a heating device capable of heating the inner wall (26) at least in each small area (64) to vaporize the second fluid (38).

6. The fluid introduction device (34) is specifically designed to inject an aqueous urea solution. A chamber mixer (10) according to any one of claims 1 to 5, characterized in that

7. 7. The chamber mixer (10) of claim 1, wherein beading (52) is incorporated into the inner wall (26), the beading being oriented with respect to the throughflow direction (22) to promote mixing of the first fluid (58) and the second fluid (38).

8. 8. The chamber mixer (10) of claim 1, wherein the one chamber contour of the inner chamber (28) tapers downstream to promote the mixing of the first fluid (58) and the second fluid (38).

9. 9. The chamber mixer (10) according to any one of claims 1 to 8, characterized in that the inlet opening (18) and the outlet opening (20) are arranged on a first housing side (16).

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