DE102014102798A1 - Exhaust treatment device - Google Patents

Abstract

An exhaust gas treatment device has a first substrate (14) through which exhaust gas flows, with an inflow-side and outflow-side end face (26) and a lateral surface (22) and a second exhaust gas-flowed substrate (16), which is arranged downstream of the first substrate (14) and with its inflow-side end face (28) facing the lateral surface (22) of the first substrate (14), so that the substrates (14, 16) lie at an angle to one another. The second substrate (16) adjoins the first substrate (14) at a small distance. Exhaust gas exiting the first substrate (14) is deflected back on the outside adjacent to its lateral surface (22) and deflected further in the direction of the inflow-side end face (28) of the second substrate (16). Between the two substrates (14, 16) there are provided a urea solution injection device (32) and a static mixing device (38). The mixing device (38) has a first deflector (40) and a second deflector (42) following in the direction of flow, which each have at least one deflecting surface (47, 64) arranged in the exhaust gas stream. The deflection surfaces (47, 64) each have, at least in sections, a spacing of approximately 10 to 30 mm, in particular approximately 18 to 25 mm, from the inflow-side end face (28) of the second substrate (16).

Description

The invention relates to an exhaust gas treatment device with two mutually angled, through which exhaust gas flowed through substrates.

Such an arrangement is known from near-engine diesel particulate filters in which, for example, an oxidation catalyst is arranged upstream of a particulate filter. Due to the structural conditions in the vicinity of the engine block, the exhaust gas flow between the outlet of the oxidation catalytic converter and the inlet of the particle filter is deflected by, for example, 90 ° here.

For the purification of exhaust gases from diesel engines, it is also beneficial for NO _x reduction to introduce an aqueous urea solution from which NH _{3 is} released, which reduces the nitrogen oxides. The urea solution and the resulting NH ₃ must be distributed as evenly as possible in the exhaust gas flow. For this purpose static mixing devices are known, which are arranged in the exhaust gas flow downstream of a urea solution injection device.

The object of the invention is to provide a compact exhaust treatment device, in which a good mixing of the urea solution or of the NH ₃ generated therefrom with the exhaust gas takes place.

According to the invention, this is an exhaust gas treatment device having a first substrate through which exhaust gas flows, which has an inflow-side and an outflow-side end face and a jacket surface, and a second substrate through which exhaust gas flows, which is arranged downstream of the first substrate and which with its inflow-side end face of the lateral surface of the first Substrate facing, so that the substrates are angled to each other and the second substrate adjoins the side of the first substrate at a small distance, provided. Exhaust gas exiting from the first substrate is deflected back on the outside adjacent to its lateral surface and deflected further in the direction of the inflow-side end face of the second substrate. Between the two substrates, a urea solution injection device and a static mixing device are provided. The mixing device has a first deflector and a second deflector following in the direction of flow, each having at least one deflecting surface arranged in the exhaust gas flow. The deflection surfaces each have, at least in sections, a distance of approximately 10 to 30 mm from the inflow-side end face of the second substrate. In particular, the distance is about 18 to 25 mm. Due to the spatial arrangement and the design of the mixing device results in a good mixing on a very short distance. In a preferred example, the distance is about 22 mm. It has been found that with this distance value, a particularly good mixing of the exhaust gas with the introduced urea solution can be achieved.

The first and the second substrate are preferably aligned between 60 and 90 °, in particular between 80 and 90 ° to each other. The outflow-side end face of the first substrate preferably lies in a plan view on the surface of the inflow-side end face of the second substrate. The substrates are cylindrical bodies, for example cordierite.

The first and the second substrate are advantageously surrounded by a common housing, so that, for example, an oxidation catalyst, a particle filter, an intermediate injection device for an aqueous urea solution and a mixing element can be combined as a compact unit. Between the inside of the housing and the substrates results in a cavity in which exhaust gas flowing out of the first substrate is deflected to the second substrate.

It is favorable if the deflecting surfaces of the first and the second deflector are seen in plan view of the inflow-side end face of the second substrate spaced from each other so as not to hinder the outflow of the exhaust gas to the second substrate.

The deflectors can lie laterally over the lateral surface of the first substrate and be attached by means of a holding arm, for example, to an inner housing surrounding the first substrate or to the common housing. Preferably, at least one angled from the support arm freely projecting wings is provided at each deflector. It is possible to produce the deflectors each from an angled sheet metal. Preferably, the first and the second deflector are separate components, each having its own holding arm. In each of the deflectors, the support arm may be disposed between two wings that may extend away from the support arm in different directions and inclinations.

In a preferred embodiment, the wing or the retaining arm of the second deflector defines a deflecting surface facing the first deflector. It extends from near the inflow-side end face of the second substrate to the side of a substantially cylindrical inner housing surrounding the first substrate. The extension of the wing or support arm along the inner housing may extend to about the axial center of the inner housing.

In order to concentrate the gas flow on the area of the mixing device, in particular on the area between the two deflectors, an outer edge of the wing facing the inside of the housing of the common housing of the two substrates can extend directly to the inside of the housing up to a free end. In this way, a flow between the wing of the second deflector and the inside of the housing is minimized.

The first deflector may have a second deflection surface which extends adjacent to the support arm between the inner housing of the first substrate and the housing inner side of the common housing to about half the diameter of the inner housing. Preferably, this second deflection surface is located on the opposite side of the first substrate as the wing of the second deflector. The second deflection surface may, for example, be aligned perpendicular to the axis of the first substrate. Among other things, it serves to concentrate the gas flow to the area of the mixing device.

A deflection surface of the second deflector, for example, an underside of the wing just described, which is directly flowed by exhaust gas coming from the first deflector, is preferably at an angle of approximately 30 to 55 ° to the inflow side end face of the underside of the wing just described second substrate inclined. The angle of inclination is in particular 44-48 ° and particularly preferably about 46 °.

Deflection surfaces of the first and second deflectors are preferably at least partially substantially in an imaginary plane extending layer of a maximum thickness of 10 mm, which runs parallel to the inflow-side end face of the second substrate.

A deflection surface of the first deflector is advantageously inclined at an angle of about 0 to 10 ° against the inflow-side end face of the second substrate. In particular, the angle of inclination is about 3 to 5 °, particularly advantageous is an angle of about 4 ° has been found.

It is possible to provide at least one opening in at least one of the deflection surfaces through which an exhaust gas NH ₃ mixture can flow to the inflow-side end face of the second substrate.

The first deflector can be used mainly for the flow control, while the second deflector can be used mainly for mixing NH ₃ with the exhaust gas.

The inflow-side end face of the second substrate may, for example, be oval. In this case, advantageously, the first deflector is disposed at one end of the long axis while the second deflector is placed at the other end of the long axis. The long axis of the inflow-side end face of the second substrate may coincide approximately in a plan view with the longitudinal axis of the first substrate.

The injection device is preferably arranged such that it injects the urea solution in particular at an acute angle to the outflow-side end face of the first substrate into a gap between the outflow-side end face of the first substrate and a housing inner side of the common housing upstream of the first deflector.

The second deflection surface of the first deflector preferably has the effect that the exiting exhaust gas flow flows approximately perpendicular to the axis of the first substrate in the direction of the second substrate and only through the gap between the inner housing and the deflection surface of the first deflector in the region between the inflow-side end face of second deflector and the inner housing of the first substrate can pass.

Viewed in plan view, the regions of the two deflectors, which are each seen outside along the axis of the first substrate, can be adapted to the contour of the inflow-side end face of the second substrate. It is favorable if in this area the smallest possible gap exists between the deflector and the inside of the common housing. In particular, it is advantageous if a substantially parallel to the inflow-side end face of the second substrate extending edge of the deflection of the first deflector, at least partially maximum at a distance of about 1 to 7 mm and in particular from 4.5 to 5.5 mm to the inside of the housing runs. This is advantageous above all on the part of the inside of the common housing which is near the outflow-side end face of the first substrate in order to guide the gas flow through the mixing device.

The invention will be described in more detail below with reference to an embodiment with reference to the accompanying drawings. In the drawings show:

1 a schematic side view of an exhaust gas treatment device according to the invention;

2 a schematic perspective view of a first substrate, a mixing device and, in sections, a second substrate of the exhaust gas treatment device from 1 ;

3 a schematic sectional view of the exhaust treatment device from 1 in a sectional plane along the axis of the first substrate;

4 a schematic perspective view of the exhaust treatment device from 1 wherein the common housing of the first and second substrates is partially removed; and

5 a schematic sectional view of the exhaust treatment device from 1 in a sectional plane transverse to the axis of the first substrate.

1 shows an exhaust treatment device 10 , here in the form of a combination of an oxidation condenser to be mounted close to the engine, a particle filter and a device for nitrogen oxide reduction.

Exhaust gas, for example from the engine block of a diesel engine, flows into an inlet opening 12 the exhaust treatment device 10 a sequentially passes through a first substrate 14 (see eg 3 ) and a second substrate 16 (see eg 4 ) and leaves the exhaust treatment device 10 through an exit opening 18 ,

The entrance opening 12 and the exit port 18 are in a common housing 20 formed, all the components of the exhaust treatment device 10 encloses. Except for the openings 12 . 18 is the case 20 formed substantially gas-tight.

The first substrate 14 which forms, for example, an oxidation catalyst is along its lateral surface 22 from a cylindrical inner casing 24 surround. The inner case 24 directs the exhaust gas from the inlet opening 12 through the first substrate to an outflow-side end face 26 of the first substrate 14 , The outflow-side end face 26 is here perpendicular to a longitudinal axis A _{1 of} the first substrate 14 aligned.

The second substrate 16 , which forms a particle filter, is angled to the first substrate 14 , wherein the longitudinal axes A _{1 of} the first substrate 14 and the longitudinal axis A _{2 of} the second substrate 16 Here are aligned at an angle of about 80 to 90 ° to each other.

The two substrates 14 . 16 are arranged and selected in their sizes so that in a plan view of the lateral surface 22 of the first substrate 14 mostly over an inflow-side end face 28 of the second substrate 16 lies. The outflow-side end face 26 of the first substrate 14 However, in plan view is a piece from the edge of the inflow-side end face 28 moved back.

The inflow-side end face 28 of the second substrate 16 here has an approximately oval contour 30 , wherein the long axis L of the oval in plan view with the longitudinal axis A _{1 of} the first substrate 14 coincides.

An injection device 32 for an aqueous urea solution in the form of a known injection nozzle is on the common housing 20 directly after the outflow-side end face 26 of the first substrate 14 arranged. The injection of the urea solution takes place here at an acute angle in a gap 34 between the outflow-side end face 26 of the first substrate 14 and the inside of the common housing 20 , The injection cone 36 , which the injected urea solution occupies, is in 3 clarified.

The one from the first substrate 14 Exiting exhaust gas flow is through the inside of the housing 20 as well as the outflow-side end face 26 of the first substrate 14 deflected by 90 °.

The exhaust gas flow hits a mixing device 38 (please refer 2 and 4 ) with a first deflector 40 and a second deflector 42 ,

The two deflectors 40 . 42 are formed as separate elements and are each bent from a one-piece piece of sheet metal. Both deflectors 40 . 42 each have a holding arm 44 on, with which they on the inner housing 24 , which is the first substrate 14 surrounds, are attached.

The first deflector 40 has a first from the support arm 44 protruding wings 46 , with a to the inner housing 24 directed first deflection 47 ,

The first deflection surface 47 lies here completely in an imaginary, flat layer of about 10 mm thickness parallel to the inflow-side end face 28 of the second substrate 16 , In the example shown, the first deflection surface 47 by 1 to 10 °, in particular by about 4 ° relative to the inflow-side end face 28 inclined.

An outer edge 48 the first deflection surface 47 runs at a maximum distance d ₁ to the inside of the housing 20 , The distance d ₁ is here a maximum of 1 to 7 mm, in particular from 4.5 to 5.5 mm, but it is also possible, the gap completely through the first deflection 47 to close.

The first deflector 40 has a second wing in this example 52 up here, roughly perpendicular to both the first wing 46 as well as the support arm 44 is aligned. The second wing 52 but also the attachment of the deflector 40 serve and act as a support arm.

The second wing 52 extends to the in 4 rear side of the inner housing 24 approximately parallel to the outflow-side end face 26 of the first substrate 14 , ie perpendicular to the longitudinal axis A _{1 of} the first substrate 14 , The second wing 52 closes the gap between the inner housing 24 and the inside of the case 20 essentially, to about half the diameter of the first substrate 14 (please refer 5 ).

The second wing 52 is opposite the outflow-side end face 26 of the first substrate 14 set back slightly to create a sufficient flow gap.

A section of the first wing 46 also extends between the second wing 52 and the edge of the upstream side face 28 in the region of the end of its long axis L.

As in 5 can be seen, thus remains on the left side in the figure, a gap between the first wing 46 and the inner housing 24 through which the first substrate 14 outgoing exhaust gas is passed.

The second deflector 42 has a first flat wing 54 , which is approximately parallel to the inflow-side end face 28 of the second substrate 16 is aligned and its outer edge 56 in the area of the end of the long axis L of the contour 30 the inflow-side end face 28 follows.

The first wing 54 is also located in the imaginary, about 10 mm high layer parallel to the inflow-side end face 28 ,

In addition, the second deflector points 42 an obliquely upward along the inner housing 24 protruding second wing 58 on, its inner contour 60 on the course of the outside of the inner housing 24 is adjusted and its outer edge 62 on the inside of the case 20 can be present. Again, the second wing 58 act as a holding arm.

The wing 58 extends here along the axis A _{1 of} the first substrate approximately to the middle of the first substrate 14 ,

The wing 58 is on the other side of the inner housing 24 like the second wing 52 of the first deflector 40 arranged.

The inflow-side end face 28 of the second substrate 16 facing side of the wing 58 forms a first deflection surface 64 of the second deflector 42 , The angle of inclination of the deflection surface 64 opposite the inflow-side end face 28 of the second substrate 16 here lies between about 44 and 48 °, in particular at about 46 °.

The lower end of the deflection surface in the figures 64 is also located in the imaginary, about 10 mm high layer parallel to the inflow-side end face 28 ,

The deflection surfaces 47 . 64 have a distance of about 10 to 30 mm, in particular from about 18 to 25 mm, from the inflow-side end face 28 , In the example shown, the distance d _{2 of} the first deflection surface 47 of the first deflector 40 about 22 mm, as well as the distance d _{3 of} the lower end of the deflection 64 of the second deflector 42 ,

The one from the first substrate 14 Exiting exhaust gas flow is through the injector 32 mixed with aqueous urea solution, which is split in the hot exhaust gas and releases NH ₃ . This mixture will be along the inside of the case 20 and the outflow-side end face 26 of the first substrate 14 as well as the second wing 52 of the first deflector 40 and the first deflection surface 47 of the first deflector 40 deflected by about 90 ° and hits the deflection 64 of the grand piano 58 of the second deflector 42 , The result is a turbulence, which ensures thorough mixing of the NH ₃ with the exhaust gas.

After mixing in the blender 38 the exhaust gas flows through the second substrate 16 and leaves the exhaust treatment device 10 through the exit opening 18 ,

Claims (13)

Exhaust treatment device with a first substrate through which exhaust gas flows ( 14 ) with an inflow-side and an outflow-side end face ( 26 ) and a lateral surface ( 22 ) and a second exhaust gas flow through substrate ( 16 ) located downstream of the first substrate ( 14 ) is arranged and with its inflow-side end face ( 28 ) of the lateral surface ( 22 ) of the first substrate ( 14 ) so that the substrates ( 14 . 16 ) are angled to each other and the second substrate ( 16 ) at a small distance to the side of the first substrate ( 14 ) and from the first substrate ( 14 ) exiting exhaust gas on the outside adjacent to its lateral surface ( 22 ) and further in the direction of the inflow-side end face (FIG. 28 ) of the second substrate ( 16 ), whereby between the two substrates ( 14 . 16 ) an injection device ( 32 ) for a urea solution and a static mixing device ( 38 ) are provided, wherein the mixing device ( 38 ) a first deflector ( 40 ) and a downstream in the flow direction second deflector ( 42 ), respectively at least one deflecting surface arranged in the exhaust gas flow ( 47 . 64 ), and the deflection surfaces ( 47 . 64 ) each at least in sections a distance (d ₂ , d ₃ ) of about 10 to 30 mm, in particular from about 18 to 25 mm from the inflow-side end face ( 28 ) of the second substrate ( 16 ) exhibit. Exhaust treatment device according to claim 1, characterized in that the first and the second substrate between 60 and 90 °, in particular 80 to 90 ° are aligned with each other. Exhaust treatment device according to one of the preceding claims, characterized in that the first and the second substrate ( 14 . 16 ) of a common housing ( 20 ) are surrounded. Exhaust treatment device according to one of the preceding claims, characterized in that the deflection surfaces ( 47 . 64 ) of the first and the second deflector ( 40 . 42 ) in plan view of the inflow-side end face ( 28 ) of the second substrate ( 16 ) are spaced apart from each other. Exhaust treatment device according to one of the preceding claims, characterized in that the deflectors ( 40 . 42 ) laterally of the lateral surface ( 22 ) of the first substrate ( 14 ) and a holding arm ( 44 ), with which it preferably at a the first substrate ( 14 ) surrounding inner housing ( 24 ) are mounted, and at least one of the support arm ( 44 ) Angled free projecting wings ( 46 . 58 ), in particular wherein the deflectors ( 40 . 42 ) consist of an angled sheet metal. Exhaust treatment device according to one of the preceding claims, characterized in that a wing ( 58 ) or a holding arm of the second deflector ( 42 ) a first deflector ( 40 ) facing deflection surface ( 64 ) and from near the upstream end face ( 28 ) of the second substrate ( 16 ) to the side of a first substrate ( 14 ) surrounding, substantially cylindrical inner housing ( 24 ), wherein the inner housing ( 24 ) near the end of the wing ( 58 ) or holding arms until approximately in the axial center of the inner housing ( 24 ). Exhaust treatment device according to claims 3 and 5 or 3 and 6, characterized in that an outside, the inside of the housing facing edge ( 48 . 62 ) of the wing ( 46 . 58 ) extends to a free end immediately along the inside of the housing. Exhaust treatment device according to one of the preceding claims, characterized in that the first deflector ( 40 ) has a second deflection surface which extends between the inner housing ( 24 ) and the inside of the housing of a common housing ( 20 ) to about half the diameter of the inner housing ( 24 ). Exhaust treatment device according to one of the preceding claims, characterized in that a deflection surface ( 64 ) of the second deflector ( 42 ) of exhaust gas from the first deflector ( 40 ) is impinged directly at an angle of about 30 to 55 °, in particular at an angle of 44-48 ° against the inflow-side end face ( 28 ) of the second substrate ( 16 ) is inclined. Exhaust treatment device according to one of the preceding claims, characterized in that the deflection surfaces ( 47 . 64 ) of the first and the second deflector ( 40 . 42 ) are in sections substantially in an imaginary, flat layer of maximum 10 mm thickness, which are parallel to the inflow-side end face ( 28 ) of the second substrate ( 16 ) runs. Exhaust treatment device according to one of the preceding claims, characterized in that a deflection surface ( 47 ) of the first deflector ( 40 ) at an angle of about 0 to 10 °, in particular at an angle of 3-5 ° to the inflow-side end face ( 28 ) of the second substrate ( 16 ) is inclined. Exhaust treatment device according to one of the preceding claims, characterized in that the injection device ( 32 ) the urea solution in a space ( 34 ) between the outflow-side end face ( 26 ) of the first substrate ( 14 ) and a housing inner side of a common housing ( 20 ) of the first and second substrates ( 14 . 16 ) and upstream of the first deflector ( 40 ) injects. Exhaust treatment device according to one of the preceding claims, characterized in that a substantially parallel to the inflow-side end face ( 28 ) of the second substrate ( 16 ) running edge ( 48 ) of the deflection surface ( 47 ) of the first deflector ( 40 ) extends at least in sections at a distance of about 1 to 7 mm, in particular from 4.5 to 5.5 mm to the inside of the housing, in particular on the outflow-side end face ( 26 ) of the first substrate ( 14 ) near part of the inside of the housing.

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