DE112013004008T5 - Method for mixing an exhaust gas stream - Google Patents

Abstract

One for mixing an exhaust gas stream with a fluid injected into an exhaust conduit comprises a first mixing element having a base connecting a first sidewall to a second sidewall spaced therefrom and a deflector disposed so that the injected fluid impinges thereon and a downstream of Baffle arranged mixing blade. A second mixing element includes first and second spaced apart mounting flanges attached to inner surfaces of the first and second sidewalls. Alternatively, the mixer includes first and second mixing elements disposed between circumferentially spaced apart slots extending axially from an open end of a tubular housing.

Description

BACKGROUND OF THE INVENTION

1. Field of the invention

The invention relates to a method for using a mixer and a mixer.

2. State of the art

According to the closest related art, several single stage mixers are known.

In the DE 10 2006 024 778 B3 a mixer is described in which a wall structure is provided for flow guide, which substantially fills the profile of a housing and thereby causes a relatively high dynamic pressure loss. The wall structure consists of several layers of a corrugated strip material, which are aligned parallel to the flow direction. The individual layers each extend transversely to the flow direction and are arranged stacked one another transversely to the flow direction. In this case, the strip material in the individual layers is stacked in such a way that between the strip material of adjacent layers a plurality of cells are formed, which can each be flowed through in the flow direction.

In addition to a round corrugation, the corrugations of the strip material can also be formed in a rectangular or trapezoidal shape, so that rectangular, hexagonal or honeycomb-shaped profiles for the individual cells can be obtained. The strip material forms a carrier, are formed in pairs on the flow guide as mixing blades. For this purpose, the carrier alternately has a region with a mixing blade and an area which is connected thereto and has no mixing fins, so that a mixing blade extends into each cell.

In the DE 20 2006 017 848 U1 a device for mixing of exhaust gases is described, wherein a lamella unit, which consists of directly successively arranged lamellae, causes a mixing of the exhaust gas. The lamella units are arranged side by side transversely to the flow direction and one behind the other in the flow direction. The lamellae are connected directly to each other without a support and arranged mirror-symmetrically with respect to a center plane.

10 2005 059 971 A1 describes an apparatus for mixing a fluid with a large gas flow rate flowing in a gas channel, in particular for admixing a reducing agent with an exhaust gas containing nitrogen oxides. For this purpose, a nozzle lance is used with a nozzle for supplying the fluid whose axis is aligned at an angle to the flow direction of the gas flow rate. The nozzle is associated with a flat mixing element at a distance which is aligned at an angle to the flow direction of the gas flow rate. At the mixer element flow vortex form, and at least a portion of the fluid enters into this flow vortex. In order to prevent deposit formation, it is provided that when a liquid is used as a fluid, the nozzle lance has at least two atomizer nozzles, which are inclined with respect to the flow direction of the gas flow and in opposite directions to each other. The atomizer nozzles are associated with a disc-shaped mixer element, so that a separation of vaporized gaseous components and non-vaporized droplet-shaped portions is possible.

In the DE 10 2006 043 225 A1 For example, an exhaust system for an internal combustion engine with an exhaust gas line leading to the exhaust gas and an injection device for injecting a liquid into the exhaust line are described. Downstream of the injector, an evaporation unit is provided in the exhaust conduit having at least one tubular plate body extending in a longitudinal direction of the exhaust conduit and providing for improved vaporization of the injected fluid. Furthermore, a clamping device of the spring type is provided, which fixes the evaporation device in the exhaust pipe or clamped against the exhaust pipe.

As the technology most closely related to the prior art is in the DE 10 2005 052 064 A1 an exhaust system with a reducing agent injection device is described in which downstream of the injection device, a plate body is arranged, which has at least one wall which extends in the longitudinal direction of the exhaust pipe and is exposed to the exhaust gas flow on both sides. The reducing agent is at least partially sprayed onto the wall, resulting in conversion of the liquid reducing agent to a vapor or gaseous state.

BRIEF DESCRIPTION OF THE INVENTION

It is an object of the invention to provide a method by which the degree of mixing between the exhaust gas and the fluid is increased depending on the shape of the exhaust pipe.

• a) der Abgasstrom wird im Bereich der Einspritzvorrichtung in einer sich parallel zur Abgasleitung erstreckenden Strömungsrichtung in der Abgasleitung geführt,
• b) das Fluid wird bezüglich einer mittigen Einspritzrichtung, die sich unter einem Winkel se zur Strömungsrichtung erstreckt, direkt auf ein in der Abgasleitung angeordnetes Ablenkelement gespritzt,
• c) mit Hilfe mindestens eines Blechteils, das auf dem Ablenkelement angeordnet und bezüglich der Strömungsrichtung mindestens teilweise unter einem Winkel sv angestellt ist, wird der Abgasstrom von seiner Strömungsrichtung teilweise in eine mittige Verteilrichtung abgelenkt,
• d) das Fluid wird vor und nach dem Auftreffen auf das Ablenkelement durch den abgelenkten Teil des Abgasstroms mindestens teilweise in die Verteilrichtung transportiert und durch das angestellte Blechteil in die Verteilrichtung abgelenkt. Hierbei ist es wesentlich, dass der Abgasstrom durch das Blechteil vor dem Mischer in die Verteilrichtung abgelenkt wird, die wesentlich von der Strömungsrichtung abweicht. Der Winkel se der Richtung, in die das Fluid eingespritzt werden kann, kann hierbei zwischen 270° und 360° variieren.

This object is achieved by a method for mixing an exhaust gas stream with a fluid in an exhaust pipe of an exhaust system in which the Fluid is injected through an injection device in the exhaust pipe, characterized by the following process steps:

• a) the exhaust gas flow is guided in the region of the injection device in a direction of flow extending parallel to the exhaust gas line in the exhaust gas line,
• b) the fluid is sprayed directly onto a deflecting element arranged in the exhaust pipe with respect to a central injection direction, which extends at an angle se to the flow direction,
• c) with the help of at least one sheet metal part, which is arranged on the deflecting element and is at least partially set at an angle sv with respect to the flow direction, the exhaust gas flow is deflected from its flow direction partially in a central distribution direction,
• d) the fluid is at least partially transported in the distribution direction before and after hitting the deflecting element by the deflected part of the exhaust gas flow and deflected by the employed sheet metal part in the distribution direction. It is essential that the exhaust gas flow is deflected by the sheet metal part in front of the mixer in the distribution direction, which differs substantially from the flow direction. The angle se of the direction in which the fluid can be injected, in this case vary between 270 ° and 360 °.

As a result, the fluid injected on one side is transported towards the center and over the entire profile of the exhaust pipe, and therefore impinges on the mixer over the entire profile of the mixer and can then be mixed with the exhaust gas stream. Even if, for reasons of installation space, the exhaust pipe is not straight, but curved, it is advantageous if the direction of movement of the fluid can be influenced by the deflection with respect to the course of the exhaust pipe.

In addition, it is provided that the fluid impinges at least partially on a correction plate which is arranged with respect to the injection direction in front of the sheet metal part, and at least partially undergoes a deflection in the flow direction and then deflected by a static mixer with at least one mixing element in a plurality of mixing directions and thus is mixed further. The correction plates are arranged above the sheet metal part substantially parallel to the sheet metal part and distributed on the side of the sheet metal part from which the fluid is injected. The distribution of the fluid in front of the mixer can be improved if further portions of the fluid stream are already deflected by the correction plate from the injection direction in the flow direction before they reach the sheet metal part.

Advantageously, the adjustment of the sheet metal part is achieved by means of a plurality of fins, which are provided on the sheet metal part and extend at equal or different angles sv; where the angle sv is between 0 ° and 85 °. The fact that the blades are employed, the sheet metal part may be arranged even parallel to the flow direction, so that only the fins provide the required deflection of the exhaust stream and thus the fluid.

In addition, it is advantageous if the correction plate has a plurality of boreholes, which extend in a drilling direction, wherein the drilling direction extends with respect to the flow direction at an angle bs between 45 ° and 135 °. As a result, a portion of the fluid may be redistributed through one or more correction plates across the profile of the mixer. The fluid may therefore partially flow further into the injector and is partially deflected by the correction plates. The accumulated part of the flow is further deflected and transported along the flow direction, while the non-accumulated part of the flow passing through the wells reaches the next correction plate in the injection direction or the sheet metal part.

The correction plate is arranged parallel to the flow direction and has a plurality of correction fins, which are employed with respect to the flow direction at an angle sk, wherein the angle sk is between 95 ° and 265 °. The correction blades are punched out of the correction plate, so that the fluid that is not accumulated, the correction plate can flow through the openings formed by the punching. At the same time, the fluid is stabilized by the correction blades, so that the fluid, unlike the flow conditions described above, is deflected more slowly by the exhaust flow in the flow direction.

On the mixing element a plurality of mixing blades are formed, which are employed with respect to the flow direction at an angle ms and with respect to the distribution direction at an angle mv, wherein the angle ms is a maximum of 70 ° and the angle mv is greater than 1 °. For the mixing process, it is advantageous if the fluid is further deflected by the mixing blades and not further guided in the same direction, which is determined by the blade or the correction blade.

For this method, a baffle is provided which is arranged to be disposed in an exhaust pipe of an exhaust system that carries an exhaust gas flow, and to deflect a fluid that is injected into the exhaust system by an injector, wherein the Deflection element in the flow direction can be arranged in front of a static mixer with at least one mixing element and at least one sheet metal part, which can be arranged in the exhaust stream, wherein the sheet metal part is at least partially employed with respect to the flow direction at an angle sv in a distribution direction, whereby the exhaust gas flow the fluid is deflected at least partially from the flow direction in the distribution direction. An employed at an angle sv slat is formed on the sheet metal part. The sheet metal part is arranged in the flow direction immediately in front of the mixer in order to obtain a symmetrical distribution of the fluid, which has already partly gone into a gaseous state, via the profile of the exhaust pipe and thus over the entire mixer profile. The smaller the gaseous portion, the greater the effect of the deflector on the mixing action by the mixer. On at least a part of the sheet metal part, a lamella is set in a distribution direction with respect to the flow direction at an angle sv, so that the exhaust gas flow with the fluid is deflected at least partially from the flow direction in the distribution direction. The influence of the sheet metal part arranged parallel to the flow direction, even on the deflection, can be neglected.

On the sheet metal part are formed at the angle sv extending lamellae. With multiple fins a deflection of the fluid is achieved such that it is distributed over the profile of the exhaust pipe. With several fins arranged one behind the other in the flow direction, the deflection of a flow element is greater because the deflection realized by the fins is partially accumulative in the flow direction.

The deflection element may be arranged in an exhaust pipe such that the fluid impinges on the deflection element to a great extent. As a result, the velocity of the fluid is first reduced by the deflector, so that the flow direction can be changed more easily.

Depending on the exhaust gas mass flow and the exhaust gas temperature, the penetration depth of the fluid into the exhaust pipe and the impact surface of the fluid on the deflector change.

The deflection element has one or more correction plates, which are arranged parallel to the flow direction or parallel to the sheet metal part. The correction plates brake the fluid and allow for early deflection of the fluid through the exhaust flow. The correction plates may have different lengths or may be constructed with equal lengths.

The correction plate has one or more correction fins, which are set at an angle sk between 95 ° and 265 °, and a plurality of openings, which are formed transversely to the flow direction by the correction fins, and / or a plurality of boreholes, which extend in a drilling direction, wherein the drilling direction extends at an angle bs between 45 ° and 135 ° with respect to the flow direction. Alternatively, a plurality of bores are provided, which extend in a drilling direction, wherein the drilling direction extends at an angle bs between 45 ° and 135 ° with respect to the flow direction. As a result, a portion of the fluid may flow directly into the fluid injection direction through an opening or well bore without being decelerated. Correction plates provide flow correction and stabilization.

The sheet metal part protrudes in the direction opposite to the flow direction over all the correction plates, and the sheet metal part is arranged with respect to the central injection direction behind the last correction plate. Due to the fact that the sheet metal part is thereby arranged directly adjacent to the wall of the exhaust pipe opposite the injection point, the sheet metal part can influence the total amount of the injected fluid.

The deflection element is mirror-symmetrical with respect to a center plane which is arranged at right angles to the flow direction, or the lamellae and / or the correction lamellae are arranged mirror-symmetrically with respect to the center plane. As a result of this symmetry, the center flow area in the exhaust conduit, into which the fluid is also injected, can be influenced to a much greater extent because the central mixing elements or flow elements have the same orientation.

Also advantageous is a multi-stage distributor which consists of a Ablenklenkelement as described above and a static mixer which is attached to the deflector or arranged indirectly behind the baffle and at least one mixing element, wherein the mixing element at least one carrier for mixing blades or a flow element having. The combination of the baffle and mixer allows a highly effective mixing process.

The sheet metal part or the correction plate is arranged on the carrier or on the flow element parallel or diagonal to the flow direction. As a result, the mixer and the deflector are at least partially or completely formed as a single part and made of the same material.

The mixing blades or the flow elements are employed with respect to the flow direction at an angle ms of up to 70 ° and with respect to the distribution direction at an angle mv of more than 1 °.

The mixing element is mirror-symmetrical with respect to the center plane, which is arranged at right angles to the flow direction, or the mixing blades and / or the carriers are arranged mirror-symmetrically with respect to the center plane.

Depending on the application, it may be advantageous if the mixing element is point-symmetrical with respect to the flow direction, or if the mixing blades and / or the carriers are arranged point-symmetrically with respect to the flow direction. Due to this arrangement, counter-rotating vortices are generated behind the mixer in the exhaust pipe.

For the assembly or retrofitting it could be advantageous if in addition a parallel to the exhaust pipe and parallel to the flow direction of the exhaust gas extending housing is provided, on which the carrier or the flow elements are arranged, wherein the housing can be arranged on or in the exhaust pipe. As a result, the mixing elements or flow elements of the mixer can be preassembled in the housing before they are inserted into the exhaust pipe.

Advantageously, the static mixer has a plurality of mixing elements for the exhaust gas, which are arranged side by side transversely to the flow direction, wherein each mixing element has a plurality of mixing blades and each mixing blade with respect to the flow direction has a rear boundary surface and two side boundary surfaces. Each mixing element has a carrier oriented parallel to the flow direction, on which the mixing blades are arranged over their rear boundary surfaces and are set relative to the carrier. Each carrier has two end surfaces, via which the respective carrier is attached to the exhaust pipe. At least three mixing elements are provided, the carriers of which are arranged in the region between the end surfaces transversely to the flow direction in each case at a distance of at least 5 mm adjacent to each other. All mixing blades are arranged with all side interfaces and with the front interface at a distance from the exhaust pipe. Preferably, the adjacent supports have a spacing between 5 mm and 100 mm, preferably between 12 mm and 15.5 mm. As a result, the mixing elements can be welded via the carriers to the exhaust pipe or to a separate housing, and the stability of the mixing element is maintained by means of the carrier and the mixing blades arranged thereon, also during an increased exhaust gas flow rate and an increased heat input. Due to the separate mounting of each mixing element and due to the mixing fins, which are arranged on the corresponding support at a distance from each other and the exhaust pipe wall, an improved flow around the fins and thus improved mixing is achieved.

A static mixer or manifold could also be advantageous if the static mixer has a plurality of mixing elements arranged side by side transverse to the flow direction, and if the respective mixing element has a parallel to the flow direction oriented carrier and a plurality of mixing blades disposed on the carrier and with respect the carrier are employed. Each carrier has two end surfaces and two connection surfaces disposed between the two end surfaces and facing each other in the direction of the carrier and spaced from the end surfaces. The end surface and the first connection surface of the respective carrier are connected to each other, so that a portion of the carrier forms a closed cell, wherein at least two mixing fins are arranged on the carrier on the portion of the carrier which encloses the cell. Thereby, the corresponding cell is not closed by a portion of a carrier on which no mixing blade is arranged, and arranged in front of the mixing blade, which extends into the cell.

For a static mixer or a distributor, it could also be advantageous if the mixer has a plurality of flow elements for the exhaust gas, which are arranged side by side transversely to the flow direction. The respective flow element is formed from a metal sheet having a wave-shaped cross-sectional profile which has a plurality of channels which extend in the direction of parallel profile axes adjacent to each other. The profile axis of the respective flow element is aligned with respect to the flow direction at an angle ms of up to 70 ° or at an angle ms of up to -70 °. The profile axes of at least two adjacently disposed flow elements are aligned at an angle ms, which are equal in direction and size. As a result, a fluid flow which reaches the center of the mixer and flows transversely to the flow direction is substantially trapped by the two central flow elements having the same orientation and can be deflected in a different direction. The cross-sectional profile is preferably regularly wave-shaped, and the profile axes are all arranged parallel to one another.

A mixer for mixing an exhaust stream with a fluid injected into an exhaust conduit includes a first mixer element having a base connecting a first sidewall to a second sidewall spaced therefrom. The first and second sidewalls are sized and shaped to conform to an inner surface of the exhaust conduit so that the sidewalls are adapted to be secured to the exhaust conduit. The first mixing element has a baffle disposed to impinge the injected fluid thereon and a mixing fin disposed downstream of the baffle for mixing the exhaust gas with the injected fluid. A second mixing element has a base connecting a first and a second mounting flange spaced therefrom. The first and second mounting flanges are secured to the inner surfaces of the first and second side walls. The second mixing element has a mixing blade for changing a flow direction of the exhaust gas flow.

Another mixer for mixing an exhaust stream with a fluid injected into an exhaust conduit comprises a tubular housing having circumferentially formed, spaced apart slots extending from an open end of the housing. A first mixing element has a central portion connecting a first peripheral region to a second peripheral region spaced therefrom. The first peripheral region is disposed within one of the slots. The second peripheral region is disposed within another of the slots. The flanges are attached to the housing. A second mixing element has a central portion connecting a third and a fourth peripheral portion spaced therefrom. The third and fourth peripheral portions are disposed in other of the slots and fixed to the housing. The second mixing element is spaced from the first mixing element.

Further advantages and details of the invention are explained in the patent claims and in the description and illustrated in the figures.

BRIEF DESCRIPTION OF THE DRAWINGS

1 shows a view of a part of an exhaust system with an exhaust pipe and an injector, in which a mixer is arranged with a deflector which is employed with respect to the flow direction;

2 shows one 1 corresponding view with a mixer and a deflector with correction plates;

3 shows one 1 corresponding view with a mixer and a deflector, which is constructed in a similar manner as a mixer;

4 shows a mirror-symmetrical mixer;

5 shows a point-symmetrical mixer with a mixing element with a cell;

6 shows a arranged in an exhaust pipe mixer according to 4 ;

7 shows a point-symmetrical mixer with carriers, which are arranged at a distance from each other;

8th shows a side view of a carrier with mixing blades, which are employed alternately;

9 shows a side view of a mixer according to 7 with a deflector with correction fins;

9a shows a side view of a mixer according to 7 with a baffle with boreholes;

10 shows a view of a mixer with flow elements which are in contact with each other;

11 shows three flow elements for a mixer according to 10 which are arranged differently with respect to their respective profile axis;

12 shows a side view of a mixer according to 10 in an exhaust pipe with a preactivated deflecting element;

13 shows an angle diagram for the deflection element and the injection device;

14 shows an angle diagram for the mixing blade with respect to the deflecting element;

15 shows a perspective view of an alternative mixer;

16 shows another perspective view of the alternative mixer;

17 shows an end view of the alternative mixer;

18 shows a cross-sectional view of the mixer through the line 18-18 in 17 ;

19 shows a partial cross-sectional view through the line 19-19 in 18 ;

20 shows a side view of the mixer;

21 shows a perspective view of another alternative mixer;

22 shows a perspective view of another alternative mixer;

23 shows a partial perspective view of another alternative mixer;

24 shows a partial end view of the in 23 shown mixer;

25 shows a perspective view of another alternative mixer;

26 shows a perspective view of the in 25 shown mixer viewed at a different angle;

27 shows an exploded perspective view of the in the 25 and 26 shown mixer; and

28 shows a partial cross-sectional view of a portion of an exhaust treatment system with another alternative mixer.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

1 shows an exhaust pipe 40 as part of an exhaust system 4 in which a fluid as a reducing agent via a on the exhaust pipe 40 arranged flange 50 is injected in an injection direction E, and one on the flange 50 arranged injection device 5 , For the sake of clarity, the figures show the central injection direction E and not the real, conical flow conditions, which in 3 are represented by the two dashed lines forming a V-shape.

In the exhaust pipe 40 an exhaust gas flows substantially parallel to the exhaust pipe 40 in the flow direction S. For the purpose of the description of the invention, it is assumed for the sake of simplicity that the flow direction S is located in front of a deflecting element 6 over the entire pipe cross-section of the exhaust pipe 40 extends parallel.

Depending on the mass flow of the reducing agent, the reducing agent flows in the direction of injection E in the exhaust pipe 40 , more or less distracted by the exhaust flow. Downstream of the injector 5 in the flow direction S is a manifold, which consists of a mixer 1 with a deflector 6 consists. The distributor is over the mixer 1 and a flange connection 41 in the exhaust pipe 40 arranged.

The reducing agent is largely incident on the deflector 6 so that the flow impulse of the reducing agent is reduced. The deflection element 6 is set at an angle SV with respect to the flow direction S, so that the exhaust gas flow through the deflecting element 6 is deflected from the flow direction S in a distribution direction V. Due to this deflected exhaust gas flow, the reducing agent along the distribution direction V entrained, partly before, but especially after it on the deflection 6 impinges, and gets into the middle of the exhaust pipe 40 guided.

2 shows a part of an exhaust system 4 as it is referring to 1 was described, with a mixer here 1 with mixing blades 31 is integrated as generally in the 4 to 7 is shown in more detail. The deflection element 6 for such mixers 1 with mixing blades 31 is in 9 shown in more detail and has as part of the deflection 6 a sheet metal part arranged parallel to the flow direction 60 with a lamella 61 , which is employed at the angle sv, and also correction plates 62 with correction blades 64 on.

The mixers 1 according to the 4 . 6 and 7 have three mixing elements 3 , which are arranged transversely to the flow direction S and adjacent to each other, and one to two additional mixing elements 3a on. The mixing element 3 . 3a basically consists of a carrier 30 . 30a and one or more mixing blades arranged thereon 31 . 31a , The respective mixing blade 31 . 31a is at its interface hR with respect to the flow direction S on the carrier 30 . 30a attached. Side boundaries sR and a front boundary vR with respect to the flow direction S form free flow margins and are not associated with any other mixing blade 31 . 31a , still with a housing 2 or an exhaust pipe 40 connected.

The carrier 30 has at its two ends in each case an end face 34 on, in which no mixing blade 31 is arranged, and according to 7 is angled. The carrier 30 is how in 7 is exemplified over the two end surfaces 34 on a housing 2 or, as in 6 is shown on an exhaust pipe 40 attached. Between the two end surfaces 34 the carrier hangs 30 free in the housing 2 or in the exhaust pipe 40 that is, it is not supported or held by any other structural element, nor does it support or hold any other structural element. In addition, the carriers extend 30 in the areas between the end faces 34 in the Essentially parallel to each other and at a distance 35 of about 13.5 mm from each other.

The housing 2 is a cylindrical tube part, on the inner wall surface 20 mixing elements 3 and, depending on the exemplary embodiment, the additional mixing elements 3a are attached. A mixer 1 This type comes with the housing 2 in an exhaust pipe 40 an exhaust system 4 used as in 2 is shown, and the exhaust gas flows through it in a flow direction S, which is parallel to the central axis 23 of the housing 2 extends.

The carrier 30 consists of a band-shaped sheet metal material with an in 8th defined width 32 and is aligned parallel to the flow direction S. The flow direction S denotes the main flow direction of the exhaust gas within the mixer 1 and extends parallel to the central axis 12 of the mixer and to the central axis 23 of the housing 2 , Due to the fact that the carrier 30 parallel to the flow direction S and thus parallel to the wall of the exhaust pipe 40 extends, the mixer can 1 simply across the flow direction in the exhaust pipe 40 to be assembled.

In the exemplary embodiments according to 7 with three mixing elements arranged substantially parallel and adjacent to each other and point-symmetrical, each of the mixing elements becomes 3 through a carrier 30 and four mixing blades 31 educated. Therefore, the entire mixing element exists 3 from a carrier 30 and four mixing blades 31 ,

The carrier 30 can be between the end faces 34 in three subareas 36 to 38 be shared. Outer parts 37 . 38 each border on opposite sides to a central portion 36 at. Each of the outer sections 37 . 38 extends at an angle with respect to the central portion 36 , ie, the middle portion 36 forms an angle α with each of the two outer portions 37 . 38 , Regarding a first axis 11 , which extends parallel to the flow direction S, cut the two outer portions 37 . 38 hence the middle part 36 at an angle α of about 12 °. The outer parts 37 . 38 are angled opposite to the central axis, so that the carrier 30 with respect to a central axis 12 , which extends parallel to the flow direction S, is point-symmetrical, ie, the carrier 30 and the mixing blades 31 are formed point symmetrical to each other and arranged.

Like the three mixing elements 3 are also the three additional mixing elements 3a in the areas near the mixing elements 3 arranged. The additional mixing element 3a is by a carrier 30a and a mixing blade 31a educated. The additional mixing element 3a is over its two end faces 34a on an inner wall surface 30 of the housing 2 and in a free-floating manner between the two end surfaces 34a attached.

With the exemplary embodiment of 4 can the carrier 30 according to the exemplary embodiment of 7 in three subareas 36 to 38 be shared. The outer parts 37 . 38 each border on opposite sides to a central portion 36 at. Each of the outer sections 37 . 38 extends at an angle with respect to the central portion 36 , ie, the middle portion 36 forms an angle α with each of the two outer portions 37 . 38 , Regarding a first axis 11 , which extends parallel to the flow direction S, cut the two outer portions 37 . 38 hence the middle part 36 at an angle γ of about 9 °. The outer parts 37 . 38 are with respect to the central axis 36 angled in the same direction, leaving the carrier 30 with respect to a plane parallel to the flow direction S extending center plane 10 is mirror symmetric.

Due to the point symmetry, the flow becomes on one side of the midplane 10 deflected upwardly and outwardly in a direction transverse to the flow direction S, inversely as the flow on the other side of the median plane 10 , The flow is in 7 represented by arrows.

In the in the 4 to 9a illustrated exemplary embodiments form the mixing blades 31 an angle β with respect to the direction of the carrier 30 and an angle ms with respect to the flow direction S. The mixing fins 31 are shown alternately. As in the 8th and 9 is shown in more detail, the angle β + 135 ° or -135 °, and the angle ms is + 45 ° or -45 °. In addition, have mixing blades 31 partially directly adjacent to each other, such as in particular 7 is shown a regular distance 33 of at least 1 mm from each other.

In an exemplary embodiment, not shown, the adjacent end surfaces 34 by two adjacent carriers 30 connected with each other. In addition, each is an end face 34a the additional mixing elements 3a each with an end surface 34 of the adjacent mixing element 3 connected. This is achieved by the three mixing elements 3 and the two additional mixing elements 3a be made from a single sheet metal strip.

On an outside 21 of the housing 2 is a security element 24 arranged as in the 7 and 9 is shown. The fuse element 24 is formed as a knob and faces the outside 21 out. With the help of the fuse element 24 can the mixer 1 in the exhaust pipe 40 against a rotational movement about the central axis 23 be fixed. In addition, the fuse element serves 24 at the same time also, in the fixed state, the rotational position of the mixer 1 with respect to the central axis 23 in the exhaust system 4 set. For this purpose, a holder, not shown, is provided at a certain position, in which the securing element 24 in the direction of the central axis 23 is pressed.

According to 9 is the mixer 1 with the housing 2 between two exhaust pipes 40 . 40 ' assembled. For this purpose, the two exhaust pipes 40 . 40 ' on both sides of the case 2 attached. For welding the two exhaust pipes 40 . 40 ' with each other and for the welded joint of the exhaust pipes 40 . 40 ' with the mixer 1 is a gap 42 between the exhaust pipes 40 . 40 ' intended. The gap 42 is generated as a result of the fact that the exhaust pipes 40 . 40 ' in the direction of the central axis 12 by adjusting elements distributed around the circumference 22 spaced from each other, on which the respective exhaust pipe 40 . 40 ' on one side in the direction of the central axis 12 adjoin one another.

The mixer 1 according to the 4 and 6 is with respect to a parallel to the flow direction S aligned center plane 10 formed mirror-symmetrical, ie, the carrier 30 and the mixing blades 31 are mirror-symmetrical to each other and arranged. These mixers 1 have three mixing elements 3 on, which are arranged parallel and adjacent to each other, wherein each of the mixing elements 3 through a carrier 30 and one or three on the carrier 30 arranged mixing fins 31 is formed.

The carrier 30 can be between the end faces 34 in three subareas 36 to 38 be shared. Outer parts 37 . 38 each border on opposite sides to a central portion 36 at. Each of the outer sections 37 . 38 extends at an angle with respect to the central portion 36 , ie, the middle portion 36 forms an angle γ with each of the two outer portions 37 . 38 , Regarding a first axis 11 , which extends parallel to the flow direction S, cut the two outer portions 37 . 38 hence the middle part 36 at an angle γ of about 9 °. The outer parts 37 . 38 are relative to the middle portion 36 angled in the same direction, leaving the carrier 30 with respect to a center axis extending parallel to the flow direction S. 12 is formed mirror-symmetrically.

The central mixing blade 31 has a slot 39 in their midst, whose length LS between 50% and 80% of the length LM of the mixing blade 31 is. Because of the slot 39 vortex formation is reduced because the flow in the central region is deflected to a lesser extent. Moreover, it is exactly in the middle of the mixer 1 in which the mass flow is greatest, the flow resistance of the mixer 1 reduced.

Except for the three mixing elements 3 is also an additional mixing element 3a under the three mixing elements 3 arranged. The additional mixing element 3a is by a carrier 30a and a mixing blade 31a formed, which also has a slot 39 having. The additional mixing element 3a is over its two end faces 34a on the inner wall surface 20 of the housing 2 and in a free-floating manner between the two end surfaces 34a attached.

5 shows a point-symmetrical mixer 1 with two identical mixing elements 3 . 3 ' , The mixing elements 3 . 3 ' each have two end surfaces 34 . 340 and two between the end faces 34 . 340 arranged connection areas 370 . 380 on. The endface 34 and the first connection area 370 of the respective carrier 30 are connected to each other, leaving a subarea 301 of the carrier 30 a closed cell 300 forms. In the subarea 301 of the carrier 30 who is the cell 300 encloses are two mixing blades 31 on the carrier 30 arranged. The mixing element 3 is over the endface 340 and the second connection area 380 at the exhaust pipe 40 attached.

The point-symmetrical mixer 1 according to the exemplary embodiments in the 5 and 7 can also work with a deflector 6 The same applies to the mirror-symmetrical mixer 1 according to the exemplary embodiments in the 4 and 6 , The deflection element 6 points, as in the 9 and 9a is shown, a sheet metal part 60 with one or more fins 61 on, which are employed at an angle sv of about 20 °. Through the slats 61 the exhaust gas flow is deflected upward in a distribution direction V, so that the reducing agent is entrained upwards. The sheet metal part 60 is right on the carrier 30 . 30a arranged and forms according to the illustrated exemplary embodiments with the mixing element 3 . 3a a structural element which is a one-piece part made of the same material.

The deflection element 6 has several correction plates 62 . 62 ' . 62 '' on, parallel to the flow direction S and parallel to the sheet metal part 60 are arranged and cause the reducing agent immediately before the mixer 1 is distributed. The correction plate 62 is right on the carrier 30 . 30a arranged and forms according to the illustrated exemplary embodiments with the mixing element 3 . 3a a structural element which is a one-piece part made of the same material.

The correction plates 62 . 62 ' . 62 '' according to 9 several correction blades 64 on, which are employed with respect to the flow direction S at an angle sk of 155 °. The correction blades 64 are, as in 14 is shown in detail, partially from the correction plate 62 punched out and stand by the correction plate 62 in the direction of the adjacent correction plate 62 and / or in the direction of the sheet metal part 60 out. As a result, under the correction lamella 64 an opening 63 in the respective correction plate 62 formed the area of the correction lamella 64 corresponds to that of the correction plate 62 protrudes. The correction lamella 64 can on one or both sides of the correction plate 62 protrude.

Likewise, the slat is 61 on the sheet metal part 60 punched out so that the sheet metal part 60 an opening 63 under the respective lamella 61 which is the area of the sheet metal part 60 protruding lamella 61 equivalent. As in 14 is shown, is the correction blade 64 from the correction plate 62 on both sides and stands the lamella 61 on one side of the sheet metal part 60 out.

The correction plates 62 . 62 ' . 62 '' according to 9a have several holes instead of correction lamellae 65 on, which are aligned in a drilling direction B, which extends at an angle bs of 90 ° to the flow direction S, and through which the exhaust gas flow with the reducing agent at least partially through the deflector 6 in the direction of the central axis 12 can flow.

3 also shows part of an exhaust system 4 as it relates to the 1 and 2 however, in this exemplary embodiment is a mixer 1 with a deflector 6 combined, in a similar way as the mixer 1 self-constructed. A mixer 1 this type is according to 10 from several adjacent flow elements 7 . 7 ' educated.

11 shows in detail that the mixer 1 from several flow elements 7 . 7 ' . 7 '' is constructed, which adjoin one another. The respective flow element 7 . 7 ' . 7 '' is from a metal sheet 70 with a wave-shaped cross-sectional profile 71 Trained, the one front 73 and several channels 72 which are adjacent to each other in the direction of parallel profile axes 74 extend. The profile axes 74 . 74 ' the two adjacent flow elements 7 . 7 ' extend with respect to the flow direction S alternately at an angle ps of + 40 ° and -40 °. As a result, the flow in through the two flow elements 7 . 7 ' trained channels simultaneously deflected upwards and downwards.

According to the invention, the profile axes extend 74 ' . 74 '' the two central flow elements 7 ' . 7 '' concerning the median plane 10 are adjacent, but parallel, ie at an angle PS of -40 °, which is equal in direction and size, so that they do not adjoin one another. As a result, as indicated by the arrows in 10 Clarifies the flow within the channels through the two flow elements 7 ' . 7 '' are formed, only upwards, ie deflected in the same direction. The angle ps corresponds to the angle ms in the exemplary embodiments described above.

Due to the same orientation of the profile axes 74 ' . 74 '' the two flow elements 7 ' . 7 '' concerning the median plane 10 opposite and at the same time adjacent to each other, is a mirror-symmetrical geometry of the mixer 1 with respect to the median plane 10 receive. The proportion of the exhaust stream and the reducing agent, in the middle of the mixer 1 flows, thus becomes within these two flow elements 7 ' . 7 '' distracted in one direction.

12 shows a cross section of a mixer 1 in which the profile axes 74 . 74 ' at an angle of ± 30 °. In front of the mixer 1 is a deflector 6 arranged in a similar manner as the mixer 1 , With the deflector 6 are also several sheet metal parts 60 with a cross-sectional profile 66 arranged directly adjacent to each other. profile axes 67 . 67 ' the deflecting element 6 adjacent sheet metal parts 60 are not employed with respect to the flow direction S, ie they extend parallel to the flow direction S. The deflection element 6 therefore forms individual channels between the individual sheet metal parts 60 in accordance with the two central flow elements 7 ' . 7 '' of the mixer 1 in which the exhaust gas flow and the reducing agent are guided in only one direction, which extends parallel to the flow direction S.

13 FIG. 12 is an angle diagram showing the above-described angles and angular relationships for the correction blade. FIG 64 and the injection direction E together with the distribution direction V and the flow direction S represents. 14 shows such an overview of the mixing blades 31 and the metal sheets 70 and the distribution direction V and the flow direction S.

The 15 - 20 show one by a reference numeral 400 designated alternative mixer. The mixer 400 has a first mixing element 402 , a second mixing element 404 , a third mixing element 406 and a fourth mixing element 408 on. The mixing elements 402 . 404 . 406 . 408 are attached to each other to a mixer 400 as an integral unit. The first mixing element 402 works as a holder or as a housing as well as a mixing element. To achieve this function, the first mixing element points 402 a first arcuate side wall 412 on, by a second arcuate sidewall 414 is spaced. An essentially flat basis 416 connects the first side wall 412 with the second side wall 414 to define a "U" shape. The base 416 may be curved or have small bends around bends 415 . 417 to provide, as shown in the figures. The first side wall 412 has a distal end 418 on, from a distal end 419 the second side wall 414 is spaced. The mixer 400 is inside the exhaust pipe 40 arranged such that the gap between the ends 418 . 419 with the injector 5 is aligned. A reagent that runs along an upper inner surface of the exhaust pipe 40 can flow, is not hindered by the presence of a mixer wall, but is between the ends 418 . 419 to flow downstream.

An integrally formed deflecting element 420 extends axially from the base 416 substantially parallel to the flow direction S. The deflection element 420 has several correction blades 422 on, which are employed with respect to the flow direction at an angle A of 30 °. A mixing blade 426 extends at an angle B of 45 ° with respect to the flow direction S. A slot 428 extends into the mixing blade 426 , so that the lamella is partially fork-shaped.

The second mixing element 404 has a first flange 430 on top of a second flange 432 is spaced. One Base 434 connects the first flange 430 and the second flange 432 , The base 434 extends substantially parallel to and offset from the base 416 , The first flange 430 has an outer surface 438 on, which engage with an inner surface 440 the first side wall 412 is arranged. The first flange 430 is on the first sidewall using a process such as welding, riveting, or other mechanical fastening technique 412 attached. Similarly, the second flange 432 an outer surface 442 on, which engage with an inner surface 444 the second side wall 414 is arranged.

The second flange 432 is on the second side wall 414 attached. The second mixing element 404 also has one or more correction blades 450 which extend at an angle C of 40 ° with respect to the flow direction S. A mixing blade 452 extends at an angle D of 40 ° in a respect to the correction blade 450 opposite direction. In the in the 15 to 20 illustrated embodiment is a single correction blade 450 upstream of two laterally spaced mixing blades 452 arranged. Another partially bifurcated mixing blade 454 extends parallel to the lamella 426 , External mixing blades 456 and 458 extend at an angle E of 45 ° with respect to the flow direction S. It should be noted that the angle E does not have to equal the angle B, and that it is often advantageous when the mixing blade 454 in a non-parallel way to the lamella 426 extends. These angles can be changed to the mixer 400 within such a system, to "adjust" so as to obtain the most uniform reductant distribution possible.

The third mixing element 406 is the second mixing element 404 essentially similar. The third mixing element 406 has a first and a second flange 464 . 468 on. One Base 470 connects the first flange 464 with the second flange 468 , The base 470 is arranged so as to be substantially parallel to the flow direction S and to the base 434 extends. The first flange 464 and the second flange 468 are shaped and arranged so that they on the inner surfaces 440 . 444 of the first mixing element 402 can be attached. In a similar way as the second mixing element 404 has the third mixing element 406 a correction lamella 474 , a pair of laterally spaced mixing blades 476 , a bifurcated mixing blade 478 and outer mixing blades 480 . 482 on. The slats of this mixing element 406 extend substantially parallel to the similar blades of the second mixing element 404 , It should be noted that this relationship is merely exemplary and other angles may be defined.

The fourth mixing element 408 is the second mixing element 404 and the third mixing element 406 essentially similar. The fourth mixing element 408 has a first and a second flange 486 . 488 on. One Base 490 connects the first flange 486 with the second flange 488 , The base 490 is arranged so as to be substantially parallel to the flow direction S and to the base 470 extends. The first flange 486 and the second flange 488 are shaped and arranged so that they on the inner surfaces 440 . 444 of the first mixing element 402 can be attached. In a similar way as the second mixing element 404 has the fourth mixing element 408 a correction lamella 494 , a pair of laterally spaced mixing blades 496 , a bifurcated mixing blade 498 and outer mixing blades 500 . 502 on.

The fifth mixing element 610 has a ninth and a tenth flange 684 . 686 on that in the slots 688 . 690 arranged and at a seventh and an eighth lip 692 . 694 are attached.

After each component under the second mixing element 404 , the third mixing element 406 and the fourth mixing element 408 at the first mixing element 402 has been attached, the mixer assembly 400 within an exhaust pipe, such as in the exhaust pipe described above 40 , to be ordered. It should be noted that the first side wall 412 and the second side wall 414 is dimensioned and shaped to fit with an inner surface of the exhaust pipe 40 come into contact or are arranged in the immediate vicinity. The mixer 400 gets inside the exhaust pipe 40 arranged at a desired axial position and at a desired angular orientation and then attached thereto by any process, such as welding, mechanical fastening, clamping or the like.

21 shows a by the reference numeral 400a designated alternative mixer. The mixer 400a is the mixer described above 400 essentially similar except that a first sidewall 412a a substantially flat section 413 which is between the arcuate sections 415 and 417 is arranged. The essentially flat section 413 is from an inner surface of the exhaust pipe 40 spaced, while the sections 415 and 417 are adapted to the inner surface and attached thereto by a process such as welding. Similarly, a second sidewall 414a a substantially planar central portion 419 on that between a curved section 421 and another curved section 423 is arranged. The essentially flat middle section 419 is from an inner surface of the exhaust pipe 40 spaced.

In the 22 to 24 denotes reference numeral 600 another alternative mixer. The mixer 600 has a plurality of spaced-apart mixing elements in the transverse direction 602 . 604 . 606 . 608 and 610 on. The mixer 600 has a housing 612 on top of each of the mixing elements 602 to 610 receives. The housing 612 may be a separate element and disposed within an exhaust pipe, or the element 612 may alternatively represent the exhaust pipe itself.

The housing 612 has an open end 614 on, starting from which several pairs of slots extend axially. A first pair of slots 616 . 618 extend axially parallel to each other from the open end 614 over a given distance and ends at stop surfaces 617 . 619 , The slots 616 . 618 can be formed as part of a stamping process, in which through the housing 612 extending incisions are formed, whereupon the inwardly projecting lips, such as a first lip 620 and a second lip 622 to be formed by a tool. The first lip 620 extends substantially parallel to the second lip 622 ,

The first mixing element 602 has a first peripheral portion or flange 624 and a second peripheral portion or flange spaced therefrom and substantially parallel 626 on. One Base 628 connects the first and second flange 624 . 626 together. The first flange 624 extends adjacent to the first lip 620 in a slot 618 , Likewise, the second flange extends 626 adjacent to the second lip 622 in a slot 616 , The first and the second flange 624 . 626 are by welding or brazing on the first and second lips 620 . 622 attached. The outer ends of the flanges 624 . 626 are under one through most of the case 612 defined cylindrical surface 632 lowered. That way, the mixer can 600 easily inserted into an exhaust pipe with a circular cross-section. The base 628 is substantially planar and has a pair of axially extending ribs 636 . 638 shown. Ribs 636 . 638 Make bending points ready for the first mixing element 602 can bend to compensate for an increase in element size caused by thermal expansion. It should be understood that any number of geometric features may be provided to achieve the desired flow and mixing characteristics. For example, it is contemplated that any of the mixing elements 602 . 604 . 606 . 608 . 610 may have one or more bends or protruding noses, similar to the correction blade 450 and / or the mixing blades 476 . 478 respectively. 480 ,

The second mixing element 604 is the first mixing element 602 is substantially similar and has a third and a fourth flange 642 . 644 on, which extend axially. A second pair of slots 646 . 648 extend through the housing 612 and take the third or the fourth flange 642 . 644 on. The second mixing element 604 is at a third and at a fourth lip 647 . 649 of the housing 612 attached.

A pair of opposite recesses 650 . 652 are in the case 612 educated. slots 654 . 656 extend through the housing 612 in the wells 650 . 652 , Inwardly extending lips, such as the lips 620 . 622 , are not from the case 612 next to the slots 654 . 656 educated. Rather, the slot 654 between end surfaces 657 . 659 of the housing 612 arranged, which are spaced apart and facing each other. The third mixing element 606 has a fifth and a sixth flange 660 and 662 on, which are essentially radial in the slots 654 . 656 extend.

The third mixing element 606 has a base section 664 on, of radially extending peripheral portions or flanges 660 . 662 is offset. The base section 664 is with the radially extending flanges 660 . 662 through angled walls 668 . 670 connected to ensure that the mixer 600 withstand repeated heating and cooling events and is not affected by the thermal expansion of the mixing elements. Each mixing element has a bend or geometric shape disposed radially outward of the central planar base portion to provide a bend location. During heating, as the width of the central, substantially planar base portions increases, a bend of each mixing element will occur, if necessary, to relieve stress and strain on the housing 612 to minimize the load applied. It is also contemplated that one or more of the mixing elements may have a central base portion and peripheral portions which are coplanar. The housing will have a spring element to account for thermal expansion, such as a portion of a depression 650 , In this configuration, no bends are provided on the mixing elements.

With regard to the embodiment of the 22 - 24 It should be noted that the peripheral sections or flanges 660 . 662 are not directed upwards, but substantially parallel to the base section 664 extend. Therefore, a surface of the flange 660 adjacent to the endface 657 arranged while the opposite surface of the flange 660 adjacent to the endface 659 is arranged. A similar arrangement exists for the flange 662 and the the slot 656 limiting end surfaces.

The fourth mixing element 608 is the second mixing element 604 essentially similar except that its seventh and eighth flange 674 . 676 which are spaced apart, in an opposite direction as the third and fourth flanges 642 . 644 extend to the outside. For this arrangement, a fifth and a sixth lips extend 678 . 680 inside to the third and fourth lip 647 . 649 out.

Each of the mixing elements may be made of sheet metal using a stamping or molding process. The size and shape of the mixing elements may be standardized or individually adapted to a particular application. In addition, although the figures show a mixer with five mixing elements, it is to be understood that other mixers may be considered which have fewer or more mixing elements than the illustrated mixers. For example, the show 23 and 24 a mixer 600a , The mixer 600a is the mixer 600 essentially similar. Therefore, similar elements are denoted by like reference numerals with an appended suffix "a". The mixer 600a has a first mixing element 604a , a second mixing element 606a and a third mixing element 608a on. The housing 612a has only the required number of slots to accommodate these mixing elements.

The 25 - 27 show an alternative mixer 700 with first to sixth mixing elements 702 . 704 . 706 . 708 . 710 and 712 , The mixing elements of the mixer 700 are the mixing elements of the mixer 400 and the mixing element 606 of the mixer 600 substantially similar, except that a body part of each of the mixing elements is formed as a substantially flat flat plate with fins extending at an angle thereto. Each of the mixing elements 702 - 710 has upwardly directed mixing fins indicated by a suffix "a". The mixing element 712 has an outwardly extending deflector 716 with correction blades 712a which point in the opposite direction as the mixing blades 702a - 710a , The mixing elements 704 to 712 also have a plurality of rear mixing blades, which are arranged in a central portion of the mixing element and denoted by a suffix "b". The Elements 704 to 710 also have rear, laterally spaced outer mixing blades, indicated by a suffix "c". It should be understood that the number of each type of mixing fin and the angle at which they extend from the substantially planar base portion may be specifically adapted to optimally distribute the injected reagent within a particular exhaust treatment system.

Each blending element has a tab portion of reduced width, indicated by the reference numeral of the blending element with an appended suffix "d", coplanar with a body portion having a full width and designated by a suffix "e". The width of the tongue is reduced to an inner, essentially cylindrical surface 718 of a ring 720 leave out.

The ring 720 has a plurality of radially inwardly extending recesses 724 on. Each recess has a slot extending through the recess 726 on. The pits and slots are provided in pairs and are indicated by suffixes "a" through "I". The slots are designated according to the paired position with the corresponding suffix. The reduced-width tongue portions with the suffix "d" are first inserted into the ring 720 introduced. The peripheral portions of the wider body portion with a suffix "e" extend through a corresponding pair of slots. For example, the peripheral portions of the body portion extend 702e laterally in slots 726a and 726b , As above with respect to the third mixing element 606 has been described, the axial position of each of the mixing elements 702 to 712 is defined by the length of the corresponding slots and an axial position of the transition between the tongue sections with the suffix "d" and the body sections indicated by the suffix "e".

On one side of each slot 726 is a spring element 730 arranged, and another spring element 732 is on the opposite side of the slot 726 arranged. For the sake of clarity are in the 26 and 27 only spring elements 730b and 732b shown. The spring elements 730 . 732 bend during a thermal event in which the temperature of the mixing element 702 increases and its width correspondingly increases due to the linear thermal expansion, radially outward. The remaining spring elements function similarly when the dimension of their associated mixing element changes with a change in temperature.

28 shows an alternative mixer 800 , The mixer 800 has a mixer 802 which is substantially similar to one of the mixers described above, such as the mixer 1 , the mixer 400 , the mixer 600 or the mixer 700 , In the mixer 800 is the mixer 802 with a secondary mixer 804 combined to the reagent distribution in the exhaust pipe 40 to improve.

The mixer 802 has a top rear mixing blade 806 on, the one in 18 illustrated mixing blade 500 or the in 9a illustrated mixing blade 31 is essentially similar. In the mixer 800 are the mixing characteristics of the mixer 802 with a secondary mixer 804 combined to solve the problem that the injected reagent on or near a top surface 810 the exhaust pipe flows 40 , The upper surface 810 is as a portion of the inner surface of the exhaust pipe 40 which extends approximately at the position downstream at which the injector 5 angled from the exhaust pipe. The secondary mixer 804 modifies the flow characteristics of the exhaust stream to improve downstream reagent distribution.

The secondary mixer 804 is as a substantially spherical projection 814 represented by the upper surface 810 protrudes radially inward. The lead 814 has a job 816 a maximum radially inner position, with respect to the diameter of the exhaust pipe 40 about 10 percent deepened. The secondary mixer 804 is arranged such that it matches the output current of the mixer 802 interacts. In particular, one is from the mixing blade 806 downstream construction line 820 shown. The construction line 820 cuts the secondary mixer 804 at a position where the projection 814 extends further radially inward. That is, the construction line 820 cuts the lead 814 at a point downstream of the site 816 , In the specific example shown in the figure, the construction line intersects 820 the lead 814 at a point where 25 percent of the projection 814 lie upstream of the intersection, while 75 percent of the projection 814 downstream from the intersection of the construction line 820 and the lead 814 lie.

Advantageously, the secondary mixer delivers 804 with its minimally inward projection little to no back pressure contribution. The exhaust gas velocity distribution remains substantially the same, while the uniformity of the reagent shows an improvement of 7 to 12% over an arrangement which simply blends the mixer 802 used. A calculated fluid dynamics modeling shows that the reagent concentration and the gradient of the reagent distribution through the use of the mixer 802 in combination with the secondary mixer 804 are diffused. It comes into consideration that the lead 814 is arranged axially such that the construction line 820 the secondary mixer 804 at a location in the range of 10 percent to 50 percent of the axial length of the projection. In this way, exhaust and reagent flowing along the top surface 810 flow, deflected radially inward, while exhaust and reagent flowing along the mixing fins 806 flow, be deflected radially outward.

In the discussion above, only exemplary embodiments of the present invention have been illustrated and described. It will be apparent to those skilled in the art from this discussion and from the accompanying drawings and claims that various changes, modifications and variations are possible within the scope of the invention as defined by the appended claims.

Claims (54)

A mixer for mixing an exhaust stream with a fluid injected into an exhaust conduit, the mixer comprising: a first mixing element having a base connecting a first sidewall to a second sidewall spaced therefrom, the first and second sidewalls each having a free distal end spaced apart from each other, wherein portions of the first and second sidewalls are sized and shaped are that they are adapted to an inner surface of the exhaust pipe, so that the side walls are adapted to be attached to the exhaust pipe, wherein the first mixing element, a deflector which is arranged so that the injected fluid impinges thereon, and a downstream of the deflector arranged mixing blade for mixing the exhaust gas stream with the injected fluid; and a second mixing element having a base interconnecting a first and a second mounting flange spaced therefrom, the first and second mounting flanges being secured to inner surfaces of the first and second sidewalls, and wherein the second mixing element comprises a mixing fin for changing the exhaust gas flow direction. The mixer of claim 1, further comprising a third mixing element having a base interconnecting a third and a fourth spaced therefrom, said third and fourth flanges being attached to inner surfaces of said first and second sidewalls, and wherein said third mixing element comprises a Has mixing blade for changing the exhaust gas flow direction. A mixer according to claim 2, wherein the base of the second mixing element extends substantially parallel to the base of the third mixing element. A mixer according to claim 3, wherein the mixing blades of the second and third mixing elements extend substantially parallel to each other. The mixer of claim 1, wherein the bases of the first and second mixing elements extend substantially parallel to each other. The mixer of claim 1, wherein the distal ends of the first and second sidewalls are circumferentially spaced at an angle of less than 90 ° as measured from a center of the exhaust conduit. The mixer of claim 1, wherein the first and second sidewalls extend over an axial length, the deflector protruding from the first and second sidewalls by being located outboard of the axial length. A mixer according to claim 7, wherein the mixing blades are arranged outside the axial length on a side of the first and the second side wall opposite the deflection element. The mixer of claim 1, wherein the deflector has a substantially planar portion extending parallel to the exhaust gas flow direction and a correction fin extending at an angle to the exhaust gas flow direction. The mixer of claim 1, wherein the portions of the first and second side walls have arcuate portions. The mixer of claim 1, wherein the mixing fins extend at an angle substantially in the range of 40 ° to 45 ° with respect to the exhaust gas flow direction upstream of the mixer. The mixer of claim 11, wherein the baffle extends at an angle of substantially 30 ° with respect to the exhaust gas flow direction upstream of the mixer. The mixer of claim 1, wherein a gap between the distal ends of the first and second sidewalls is aligned with the injected fluid under a common angular orientation. The mixer of claim 1, wherein the first sidewall has a first curved portion and a second curved portion interconnected by a substantially planar portion, the planar portion adapted to be spaced from an interior surface of the exhaust conduit. The mixer of claim 14, wherein the second sidewall has a first curved portion and a second curved portion interconnected by a substantially planar portion, the planar portion of the second sidewall extending substantially parallel to the planar portion of the first sidewall. A mixer for mixing an exhaust stream with a fluid injected into an exhaust conduit, the mixer comprising: a housing having a first sidewall and a second sidewall spaced therefrom, the first sidewall and the second sidewall each having a free distal end spaced apart from each other and portions of the first and second sidewalls adapted to be secured to the exhaust conduit to become; a first mixing element having a substantially planar baffle disposed to impinge the injected fluid thereon and a plurality of correction fins protruding from the baffle at an angle; and a second mixing element interconnecting the first and second sidewalls and extending substantially parallel to the first mixing element, the second mixing element having a mixing fin for changing an exhaust gas flow direction. The mixer of claim 16, wherein the first and second sidewalls extend over an axial length, the deflector protruding from the first and second sidewalls by being located outboard of the axial length. The mixer of claim 17, wherein the baffle extends upstream of the first and second sidewalls substantially parallel to the exhaust gas flow direction. The mixer of claim 18, wherein a gap between the distal ends of the first and second sidewalls is aligned with the injected fluid under a common angular orientation. The mixer of claim 16, wherein the first sidewall has a substantially planar portion that extends perpendicular to the deflector and is disposed between the first sidewall portions and that is adapted to be attached to the exhaust conduit. The mixer of claim 16, wherein the correction blades comprise upwardly directed portions of a common one-piece plate from which the deflection member and the first mixing element are formed, the correction blades having free edges and a fixed portion. A mixer according to claim 21, wherein the first mixing element has an upwardly directed mixing blade at its rear end. A mixer for mixing an exhaust stream with a fluid injected into an exhaust conduit, the mixer comprising: a tubular housing having circumferentially spaced slots extending axially from an open end of the housing; a first mixing element having a central portion connecting a first peripheral portion to a second peripheral portion spaced therefrom, the first peripheral portion disposed within one of the slots, the second peripheral portion disposed within another of the slots, and the peripheral portions secured to the housing; and a second mixing element having a central portion interconnecting a third and a fourth circumferential portion spaced therefrom, the third and fourth circumferential portions disposed within and secured to the housing; and wherein the second mixing element is spaced from the first mixing element. The mixer of claim 23, wherein the center portions of the first and second mixing elements are substantially planar and extend substantially parallel to each other. The mixer of claim 23, wherein each of the first and second peripheral portions extends along a plane other than a plane containing the center portion of the first mixing element so that the first mixing element bends upon heating, thereby causing the housing applied load is reduced. The mixer of claim 23, wherein the first and second peripheral portions lie in a common plane with the center portion of the first mixing element. The mixer of claim 26, wherein the housing has spring portions arranged and dimensioned to flex in response to a size increase of the first mixing element caused by heating. The mixer of claim 23, wherein the first mixing element does not project beyond a cylindrical shape of an outer surface of the housing. The mixer of claim 23, wherein the housing has first and second inwardly projecting lips, wherein the first lip extends along one side of one of the slots and is secured to the first peripheral portion and the second lip extends along one side of another of the slots and attached to the second peripheral portion. The mixer of claim 29, wherein the first and second peripheral portions extend substantially perpendicular to the center portion of the first mixing element. The mixer of claim 29, wherein the first lip overlaps the first peripheral portion. The mixer of claim 23, wherein the first and second peripheral portions extend in the opposite direction with respect to the third and fourth peripheral portions. The mixer of claim 23, wherein the housing has circumferentially spaced recesses, the slots being disposed within the recesses. The mixer of claim 32, wherein the housing has first and second opposing end surfaces on opposite sides of one of the slots, the first peripheral portion being disposed between the first and second end surfaces. A mixer according to claim 23, wherein the first and second mixing elements each comprise a metal sheet. The mixer of claim 23, wherein the housing is adapted to be at least partially disposed within and secured to the exhaust conduit. The mixer of claim 23, wherein the first mixing element has a rib extending substantially parallel to the exhaust gas flow direction. The mixer of claim 23, wherein the slots receiving the first mixing element terminate at abutment surfaces, the position of the first and second peripheral portions being limited by the abutment surfaces. A mixer for mixing an exhaust stream with a fluid injected into an exhaust conduit, the mixer comprising: a primary mixer having a first mixing element having a mixing blade for mixing the exhaust gas with the injected fluid; and a secondary mixer disposed downstream of the primary mixer, the secondary mixer having an exhaust flow deflector integrally formed with the exhaust conduit and having an inwardly extending surface with a maximum inner protrusion point, the secondary mixer being disposed such that a the mixing blade extending construction line intersects the inwardly extending surface upstream of the maximum inner projection point. The mixer of claim 39, wherein the primary mixer includes a second mixing element having a mixing fin for changing an exhaust gas flow direction, the first mixing element being radially spaced from the second mixing element and located closer to a fluid injection point than the second mixing element. The mixer of claim 40, wherein the first mixing element extends substantially parallel to the second mixing element. Mixer according to claim 41, wherein the mixing blade of the first mixing element deflects the exhaust gas flow substantially radially outward. The mixer of claim 39, further comprising a baffle disposed upstream of the mixing element at a location where the injected fluid impinges thereon. The mixer of claim 43, wherein the deflector has a substantially planar portion extending substantially parallel to the exhaust gas flow direction and a correction fin extending at an angle to the exhaust gas flow direction. The mixer of claim 44, wherein the deflector extends at an angle of substantially 30 ° to the exhaust gas flow direction upstream of the mixer. The mixer of claim 39, wherein the mixing fin extends at an angle in the range of substantially 40 ° to 45 ° with respect to the exhaust gas flow direction upstream of the mixer. The mixer of claim 39, wherein the radially inwardly extending surface is a spherical recess of the exhaust conduit. The mixer of claim 39, wherein the construction line intersects the inwardly extending surface at an axial position that is substantially equal to half the distance between the maximum inner protrusion point and a forward edge of the spherical recess. The mixer of claim 39, wherein the maximum inner protrusion point extends radially inward over a distance equal to about ten percent of the exhaust conduit diameter. A mixer for mixing an exhaust stream with a fluid injected into an exhaust conduit, the mixer comprising: a tubular housing having circumferentially spaced slots extending axially from an open end of the housing; a first mixing element having a substantially planar body having a first peripheral portion and a second peripheral portion, wherein the first peripheral portion is disposed within one of the slots, the second peripheral portion is disposed within another of the slots, and the peripheral portions are fixed to the housing; and a second mixing element having a substantially planar body having third and fourth peripheral portions, the third and fourth peripheral portions disposed within and secured to the housing, and wherein the second mixing element is spaced from the first mixing element. The mixer of claim 50, wherein the tubular housing has an inwardly extending spring member coupled to the first mixing element that moves to receive a size increase of the first mixing element caused by a temperature increase. A mixer according to claim 50, wherein the first mixing element has a tongued portion of reduced width in the housing. A mixer for mixing an exhaust stream with a fluid injected into an exhaust conduit, the mixer comprising: a tubular housing having an open upstream end and an open downstream end, the housing being sized to fit into and be secured to the exhaust conduit; a first mixing element having a planar portion having a first edge and an opposite second edge, the first and second edges secured to the housing, the first mixing element having mixing fins extending at an angle from the planar portion, and wherein adjacent mixing blades extend in opposite directions relative to each other, the mixing blades extending beyond the downstream end of the housing; and a second mixing element having a planar portion having a third edge and an opposing fourth edge spaced therefrom, the third and fourth edges being secured to the housing, the second mixing element being spaced from and extending parallel to the first mixing element; second mixing element having mixing fins extending at an angle from the planar portion, and wherein adjacent mixing fins extend in opposite directions relative to each other, wherein the mixing fins of the second mixing element extend beyond the downstream end of the housing The mixer of claim 53, wherein the fluid is injected along an injection axis and the mixer is arranged such that the fluid injection axis intersects the first and / or second mixing elements.

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