Mixing tube

Abstract

The present invention relates to a mixer for an exhaust gas system for mixing additives into the exhaust gas stream of an internal combustion engine, the mixer having a first housing and at least a second housing continuously arranged in a circumferential direction relative to a central axis, each housing having at least two housing edges offset in a circumferential direction and each forming a flow edge, wherein the flow edges of two circumferentially adjacent housing edges of the two different housings define an inflow opening, such that at least one pipe end arranged coaxially with the central axis is provided with a circumferential pipe profile having a nominal radius for connection to an exhaust pipe, the pipe end being formed by the circumferentially adjacent housing.

Description

Technical Field

[0001] The present invention relates to a mixer for an exhaust gas system for mixing additives into the exhaust gas stream of an internal combustion engine, the mixer having a first housing and at least a second housing arranged continuously in a circumferential direction relative to a central axis, each housing having at least two housing edges arranged offset in a circumferential direction and each forming a flow edge, wherein the flow edges of two circumferentially adjacent housing edges of the two different housings define an inflow opening.

[0002] The present invention relates to a system comprising a mixer integrated into an exhaust gas treatment section and a syringe for metering additives into the mixer. Background Technology

[0003] A hybrid tube formed by two half-shells is known from WO 2016 / 180244 A1. The two half-shells have the same cross-sectional shape along their entire length. The hybrid tube wall is located at the ends to which the two half-shells are fastened. Summary of the Invention

[0004] The purpose of this invention is to design and arrange the mixing pipe to ensure optimal connection to the exhaust gas system while reducing material usage.

[0005] According to the invention, the objective is achieved by having at least one pipe end arranged coaxially with the central axis provided with a circumferential pipe profile having a nominal radius Rn and for connection to an exhaust pipe, the pipe end being formed by a circumferentially adjacent housing.

[0006] This ensures that the mixer can be directly connected to the exhaust pipe to be connected via the provided pipe end. This is typically done by welding. The two housings are preferably designed as half-housings and have the same geometry, so that the entire mixer can be constructed with a half-housing geometry. The pipe profile is preferably circular. However, cylindrical or elliptical profiles are also provided. In the case of an elliptical profile, the nominal radius Rn corresponds to the radius of the half-axis, as explained in more detail in the exemplary embodiments. To construct the mixer, two identical half-housings are placed abutting against each other, with one half-housing rotated 180° relative to the other.

[0007] For this purpose, it may also be advantageous for at least two housings to be directly form-fitted and / or integrally and / or force-fitted connected to each other at the pipe ends. Form-fitting, integral, and / or force-fitting connections at the pipe ends ensure sufficient stability of the mixer formed by two or more housings. Additionally, fastening the housings to each other at the ends ensures that the pipe ends form a pipe profile or connection profile for connection to the exhaust pipe or mixer housing.

[0008] Furthermore, it can be advantageous if at least one housing edge of at least one housing has a radially extending notch with a guide radius Re < Rn in the region of the flow edge. The notch in the region of the housing edge ensures its radial offset, such that a corresponding inflow opening is formed or enlarged relative to the adjacent housing edge. The notch preferably extends from 20° to 60°, and starting from the flow edge, continuously decreases from the guide radius Re to the nominal radius Rn. Thus, an orienting component is given to the inflow opening or its normal vector in the circumferential direction, such that the exhaust gas flowing in the circumferential direction can enter the inflow opening in a simplified manner and eddies are formed inside the mixer due to the tubular basic shape of the mixer. The notch is preferably provided on only one housing edge.

[0009] It can also be advantageous if at least one housing edge of at least one housing has a radially extending protrusion with a guide radius Ra > Rn in the region of the flow edge. By using the protrusion in the region of the housing edge, the exhaust gas flow flowing into the inflow opening in the circumferential direction is thus improved, or the normal vector N of the inflow opening is oriented relative to the circumferential direction. The protrusion also decreases from its guide radius Ra to the nominal radius Rn in an angular range between 20° and 60°. This helps to form eddies inside the mixer. The radial offset between the housing edge with the protrusion and the adjacent housing edge defines the inflow opening. This advantage has been achieved by forming the protrusion on only one housing edge.

[0010] Advantageously, it can be provided that the housing edge with the notch of one housing is arranged directly adjacent in the circumferential direction to the housing edge with the protrusion of another housing. The radial offset between the housing edge with the notch and the housing edge with the protrusion defines the maximum inflow opening size. By using two housings with the same geometry and the corresponding relative position between the two housings (i.e., pivoting one housing by 180°), according to the present invention, the notch of one housing is placed adjacent to the protrusion of the adjacent housing, such that the maximum inflow opening size described above is ensured.

[0011] What may be particularly important for the present invention is that the second tube end is provided with a tube profile, and the axial length of each flow edge is defined by the two tube ends. The tube profile of the second tube end is preferably the same as the tube profile of the first tube end, i.e., also circular or also elliptical. In the case of forming the second tube end, the stability of the mixer formed by at least two half - housings is significantly improved. Thus, the two tube ends define the axial length of the available flow edges, which define the inflow opening. The tube ends are also formed by two half - housings; thus, the two half - housings have corresponding axial edges, and the two edges together form the tube end. The two housings or all housings are properly form - fitted and / or integrally connected at the tube ends to fasten the housings to each other.

[0012] In combination with the design and arrangement according to the invention, it is advantageous that each housing is designed as a semi-shell and extends 180° to 190° in the circumferential direction.

[0013] Furthermore, it is advantageous for each housing to have a component edge at least in a region at one end of the tube and at at least one housing edge, each component edge abutting against and / or connecting to the housing edge of an adjacent housing in the radial direction. The component edge is preferably located only on one housing edge of a particular housing, such that when a pair of housings are used, both component edges can thus be used to connect adjacent housing edges. The component edge is preferably curved in the radial direction, such that although the two housing edges overlap in the circumferential direction, the two half-housings or housings may be coaxially aligned relative to a common central axis. The component edge is rigidly connected to the adjacent housing edge to which it abuts by means of form fit and / or integral connection. The component edge extends at least above the portion of each housing where a corresponding connection to an adjacent housing is required. Alternatively, the component edge may also be arranged, in principle, in the region of the housing edge forming the boundary of a flow edge or inflow opening.

[0014] Additionally, it is advantageous that at least one or all of the housings are designed as a single-piece, single-layer sheet metal section. Therefore, simple sheet metal sections that can be produced during deep drawing can be used.

[0015] Furthermore, it is advantageous that Rn-Re <=> Ra-Rn. Preferably, the difference between the nominal radius Rn and the guide radius Re of the notch is equal to the difference between the nominal radius Rn and the guide radius Ra of the protrusion. Other ratios are possible. Attached Figure Description

[0016] Further advantages and details of the invention are set forth in the claims and description, and are illustrated in the drawings. In the drawings:

[0017] Figure 1 This is a perspective view of the mixer;

[0018] Figures 2a-2c Different tube profiles are shown;

[0019] Figure 3 This is a schematic diagram of the exhaust gas system;

[0020] Figure 4 An alternative embodiment of the mixer is shown. Detailed Implementation

[0021] Figure 1The mixer 1 shown is composed of two identical half-shells 2 and 3. Each half-shell 2 and 3 has component edges 4.2, 4.2', 4.3, and 4.3', which are positioned radially relative to the central axis 1.5 of the mixer 1 against the shell edges 2b and 3b of an adjacent shell. One component edge 4.2 or 4.3 of each half-shell 2 and 3 is curved in the radial direction, while the other component edge 4.2' or 4.3' is not curved. Each half-shell 2 and 3 is defined circumferentially by two shell edges 2a, 2b, 3a, and 3b, respectively. The axial end portions of the shell edges 2a, 2b, 3a, and 3b form component edges 4.2, 4.2', 4.3, and 4.3', respectively.

[0022] In the regions of each tube end 1.1, 1.3, the two assembled half-shells 2, 3 form tube profiles 1.2, 1.4 with a central axis 1.5 and a circular cross-section. In the connection region of the two half-shells 2, 3, the tube profiles 1.2, 1.4 are formed by the axial end assembly edges 4.2, 4.3.

[0023] Between the two tube ends 1.1, 1.3, each housing 2, 3 has a notch 2.1, 3.1 and a protrusion 2.2, 3.2. Each pair of notches and protrusions 2.1, 2.2, 3.1, 3.2 establishes a radial offset of size Ra-Re between the relevant housing edges 2a, 2b, 3a, 3b in the region of the housing edges 2a, 2b, 3a, 3b. Ra is the guide radius of the protrusion 2.2, 3.2, and Re is the guide radius of the notch 2.1, 3.1. The guide radius Ra of the protrusion 2.2, 3.2 is greater than the nominal radius Rn of the tube profile 1.2, 1.3 at the end. The guide radius Re of the notch 2.1, 3.1 is less than the nominal radius Rn. If the protrusion 2.2, 3.2 and / or the notch 2.1, 3.1 are omitted in at least one housing, then the guide radius Ra or the guide radius Re is equal to the nominal radius Rn.

[0024] Each protrusion, 2.2 and 3.2, gradually narrows in the circumferential direction and approaches the nominal radius Rn. According to... Figure 1 In an exemplary embodiment, this method is performed at a circumferential angle of approximately 30°. This applies to notches 2.1 and 3.1. The notches widen in the circumferential direction and also approach the nominal radius Rn at a circumferential angle of approximately 30°. The maximum values ​​of protrusions 2.2 and 3.2 and notches 2.1 and 3.1 are in the regions of the relevant shell edges 2a, 2b, 3a, and 3b. The previously described approach toward the nominal radius Rn proceeds from the shell edges 2a, 2b, 3a, and 3b.

[0025] In the regions of the protrusions and recesses 2.1, 2.2, 3.1, and 3.2, the corresponding shell edges 2a, 2b, 3a, and 3b form flow edges 2c and 3c that define the inflow openings 23. Each inflow opening 23 is defined by a protrusion 2.2 or 3.2 of one shell 2 or 3 and a corresponding recess 2.1 or 3.1 of the other shell 3 or 2. Therefore, two inflow openings 23 are formed by shell edges 2a, 2b, 3a, and 3b.

[0026] The inlet opening 23 has a normal vector N that is approximately tangent to the circumferential direction. Exhaust gas flowing in from the outside enters the mixer 1 through the inlet opening 23 with velocity and directional components guided substantially in the circumferential direction, and is subsequently guided forward in the vortex with an axial component due to the basic cylindrical shape of the mixer 1.

[0027] according to Figures 2a to 2c In the exemplary embodiment shown, the pipe profile 1.2 can be circular or elliptical. Starting from the inflow opening 23 arranged on the side, the radius of the ellipse on the side is referred to as the nominal radius Rn. The same result is produced when the inflow opening 23 is shifted upward or downward in the circumferential direction.

[0028] Figure 3 An exemplary embodiment relates to an exhaust system 5 connected to an internal combustion engine 6. The exhaust system 5 has an exhaust treatment section 5.1 or a mixer housing in which a mixer 1 is disposed. The exhaust treatment section 5.1 is connected to the internal combustion engine 6 or another exhaust treatment device via an exhaust pipe 5.2. Furthermore, the exhaust treatment section 5.1 has a syringe 5.3, which is placed at a second end 1.3 of the mixer 1, and an additive is injected into the mixer 1 through the syringe. The mixer 1 is connected to the exhaust pipe 5.2 via a first end 1.1.

[0029] In the regions 2a, 2b, 3a, 3b at each shell edge, Figure 4 An alternative embodiment of the mixer 1 shown has only notches 2.1, 3.1 and no protrusions. However, additional notches 2.3, 3.3 and additional protrusions 2.4, 3.4 are provided in each region between each pair of housing edges 2a, 2b, 3a, 3b.

[0030] Component Symbol List

[0031] 1. Mixer

[0032] 1.1 Pipe end

[0033] 1.2 Pipe Profile

[0034] 1.3 Second pipe end

[0035] 1.4 Pipe Profile

[0036] 1.5 Central Axis

[0037] 2. Shell, First Shell, Half Shell

[0038] 2a Shell edge

[0039] 2b Shell edge

[0040] 2c Flow Edge

[0041] 2.1 Notch

[0042] 2.2 Protrusion

[0043] 2.3 Other notches

[0044] 2.4 Other protrusions

[0045] 3. Shell, Second Shell, Half Shell

[0046] 3.1 Notch

[0047] 3.2 Protrusion

[0048] 3.3 Other notches

[0049] 3.4 Other protrusions

[0050] 3a Shell edge

[0051] 3b Shell edge

[0052] 3C Flow Edge

[0053] 4.2 Component Edges

[0054] 4.2' Component edge

[0055] 4.3 Component Edges

[0056] 4.3' Component Edge

[0057] 5. Exhaust Gas System

[0058] 5.1 Exhaust gas treatment section and mixer housing

[0059] 5.2 Exhaust Gas Pipe

[0060] 5.3 Syringe

[0061] 6. Internal Combustion Engine

[0062] 23 Inflow Opening

[0063] The normal vector of N 23

[0064] Ra, the guiding radius of the protrusion

[0065] Re: Guide radius of the notch

[0066] Rn nominal radius

Claims

1. A mixer (1) for mixing additives into the exhaust gas stream of an internal combustion engine, the mixer having a first housing (2) and at least a second housing (3), the first and second housings (2, 3) being continuously arranged in the circumferential direction relative to a central axis (1.5), each housing (2, 3) having at least two housing edges (2a, 2b, 3a, 3b), the at least two housing edges being offset in the circumferential direction and each forming a flow edge (2c, 3c), wherein the flow edges (2c, 3c) of two circumferentially adjacent housing edges (2a, 3b) of the two different housings (2, 3) define an inflow opening (23). Its features are: At least one first pipe end (1.1) arranged coaxially with the central axis (1.5) is provided with a circumferential pipe profile (1.2) having a nominal radius Rn and is used to connect to an exhaust pipe (5.2). The first pipe end (1.1) is formed by a circumferentially adjacent housing (2, 3).

2. The mixer (1) according to claim 1. Its features are: The at least two housings (2, 3) are directly and / or integrally and / or forcefully connected to each other at the first tube end (1.1).

3. The mixer (1) according to claim 1 or 2. Its features are: At least one shell edge (2a, 3a) of at least one shell (2, 3) has a radially extending notch (2.1, 3.1) with a guiding radius Re < Rn in the region of the flow edge (2c, 3c).

4. The mixer (1) according to claim 3. Its features are: At least one shell edge (2a, 3a) of at least one shell (2, 3) has a radially extending protrusion (2.2, 3.2) with a guiding radius Ra > Rn in the region of the flow edge (2c, 3c).

5. The mixer (1) according to claim 4. Its features are: The shell edge (2a, 3a) of one shell (2) having the notches (2.1, 3.1) is arranged in the circumferential direction directly adjacent to the shell edge (2a, 3a) of another shell (3) having the protrusions (2.2, 3.2).

6. The mixer (1) according to claim 1 or 2. Its features are: The second pipe end (1.3) is provided with a pipe profile (1.4), and the axial length of each flow edge (2c, 3c) is defined by the first pipe end (1.1) and the second pipe end (1.3).

7. The mixer (1) according to claim 1 or 2. Its features are: Each shell (2, 3) is designed as a semi-shell and extends 180° to 190° in the circumferential direction.

8. The mixer (1) according to claim 1 or 2. Its features are: Each housing (2, 3) has an assembly edge (4.2, 4.3) in at least one region of a pipe end (1.1, 1.3) and at at least one housing edge (2a, 3a), each assembly edge (4.2, 4.3) abutting against the housing edge (2a, 2b, 3a, 3b) of the adjacent housing (2, 3) and / or connected in the radial direction to the housing edge (2a, 2b, 3a, 3b) of the adjacent housing (2, 3).

9. The mixer (1) according to claim 1 or 2. Its features are: At least one housing (2, 3) or all of the housings are designed as a one-piece, single-layer metal plate portion.

10. The mixer (1) according to claim 4. Its features are: The difference between the nominal radius Rn and the guide radius Re of the notch is equal to the difference between the nominal radius Rn and the guide radius Ra of the protrusion.

11. The mixer (1) according to claim 3. Its features are: Each housing (2, 3) has an additional radially extending notch (2.3, 3.3) in the region between the two housing edges (2a, 2b, 3a, 3b).

12. The mixer (1) according to claim 4. Its features are: Each housing (2, 3) has an additional radially extending protrusion (2.4, 3.4) in the region between the two housing edges (2a, 2b, 3a, 3b).

13. An exhaust gas system comprising a mixer (1) according to any one of the preceding claims integrated into an exhaust gas treatment section (5.1) and a syringe (5.3) for metering an additive into the mixer.

14. The exhaust gas system according to claim 13, Its features are: The exhaust gas treatment section (5.1) and the mixer (1) are integrated into the exhaust gas system (5) of the internal combustion engine (6).

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