RING CATALYST

Abstract

A catalytic converter for the aftertreatment of exhaust gases from an internal combustion engine, with a first tubular central flow section, with a deflecting device for deflecting the flow direction and with an annular flow section which has at least one catalytically active matrix. The tubular flow section is formed by an inner jacket and the annular flow section is formed by an outer jacket surrounding the inner jacket, wherein the deflecting device is formed by a flat half-shell.

Claims

1. A catalytic converter for the aftertreatment of exhaust gases from an internal combustion engine, comprising: an inner jacket; an outer jacket; a first tubular central flow section formed by the inner jacket; an annular flow section which has at least one catalytically active matrix, the annular flow section is formed by the outer jacket surrounding the inner jacket; and a deflecting device for deflecting the flow direction of exhaust gases; wherein the deflecting device is formed by a flat half-shell, and the deflecting device is connected to the outer jacket.

2. The catalytic converter of claim 1, wherein the inner jacket and the outer jacket have an identically long extent in the axial direction or the main flow direction in the tubular central flow section.

3. The catalytic converter of either of claim 1, further comprising: an at least partially circumferentially encircling confusor arranged on the end region of the inner jacket facing the deflecting device; wherein the at least partially circumferentially encircling confusor bundles the exhaust-gas flow.

4. The catalytic converter of claim 3, wherein the confusor extends in the axial direction over a length m.

5. The catalytic converter of claim 4, wherein m assumes values in the range of 0.015≤m/D≤0.44, wherein D is the inner diameter of the outer jacket.

6. The catalytic converter of one of claim 1, wherein the catalytically active matrix is arranged in the annular flow section, such that the inflow side of the catalytically active matrix ends flush with the outer jacket.

7. The catalytic converter of one claim 1, the deflecting device further comprising a first region which is arranged centrally above the central axis of the catalytic converter and is dome-shaped.

8. The catalytic converter of claim 1, the deflecting device further comprising a second region which is formed by an annular depression.

9. The catalytic converter of claim 8, wherein the second region is arranged radially outside the inner jacket.

10. The catalytic converter of claim 1, the deflecting device further comprising a third region which is arranged in the radial direction on the outer edge of the catalytic converter and is formed by an annular bulge.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0023] In the following, the invention is explained in detail using exemplary embodiments with reference to the drawings. In the drawings:

[0024] FIG. 1 shows a plan view of the deflecting device;

[0025] FIG. 2 shows a sectional view through a ring catalytic converter according to the invention; and

[0026] FIG. 3 shows a further sectional view through a ring catalytic converter with a detailed illustration of the deflecting device.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0027] The following description of the preferred embodiment(s) is merely exemplary in nature and is in no way intended to limit the invention, its application, or uses.

[0028] FIG. 1 shows a deflecting device formed by a half-shell 1. The half-shell has a first central depression 2 which is formed in the half-shell, for example by deep-drawing. In the radial direction, the first depression 2 is surrounded by a second annular depression 3. The annular depression 3 is adjoined in the radial direction by a bulge 4 which was formed in the half-shell 1 in the opposite direction to the depressions 2 and 3.

[0029] The half-shell 1 is connected to the outer jacket in a manner comparable to a cover in such a way that the inner surface of the half-shell 1 serves as a flow-directing element for the from the tubular flow section and the exhaust gas is thereby transferred into the annular outer flow section.

[0030] FIG. 2 shows a sectional view through a ring catalytic converter. The tubular central flow section 5 through which the exhaust gas flows along the arrows 6 is shown. A confusor 7 is arranged in the axial direction at the end of the flow section 5, the confusor 7 bundling the exhaust gas flowing in the flow section 5 and directing same in a targeted manner into the deflecting device formed by the half-shell 1.

[0031] FIG. 2 also shows that the inner jacket 8 forming the flow section 5 extends in the axial direction precisely as far as the outer jacket 9. There is no protrusion of the inner jacket 8 beyond the outer jacket 9 in the flow direction.

[0032] A catalytically active matrix 10 is arranged in the annular gap formed between the inner jacket 8 and the outer jacket 9. The inlet side of the catalytically active matrix 10 is preferably arranged flush with the end of the outer jacket 9 and the inner jacket 8 facing the deflecting device 1.

[0033] The exhaust gas flowing through the flow section 5 is diverted radially outward in the deflecting device 1 and finally by a further 90 degrees and is thus directed through the annular flow channel 14 between the inner jacket 8 and the outer jacket 9. After flowing through the catalytically active matrix 10, the exhaust gas may finally flow on via suitable flow paths.

[0034] FIG. 3 shows a sectional view through a ring catalytic converter according to the invention, wherein the illustration in FIG. 3 shows an embodiment of the design of the deflecting device 1. According to the invention, the different radii of the depressions and bulges follow specific size ratios, as a result of which a desired flow deflection is achieved.

[0035] The deflecting device has a first region 11 which is arranged centrally in an extension of the tubular flow section 5. This first region 11 is dome-shaped and has a central circular depression 2. The depression 2 is described by a first radius R1, which describes the inner radius of the depression 2, and by a second radius R2, which describes the radius at the transition from the dome-shaped structure to the depression 2.

[0036] The upper right region of FIG. 3 shows a detailed view of the depression 2, which reveals in detail the ratio that is between the radii R1 and R2 and the further dimensions a, b, c, e and f.

[0037] For the radius R1, the latter is in a value range of 0.005≤R1/D≤0.33. The preferred value range of 0.005≤R2/D≤0.33 applies analogously for the radius R2. For the other dimensions a, c, e and f, which each describe lengths and distances between the points shown, the preferred value ranges are between 0.005≤a/D≤0.33; 0.005≤c/D≤0.33; 0.005≤e/D≤0.33; 0.01≤f/D≤0.25. For the dimension b, 0.005≤b/D≤0.33 applies.

[0038] Reference sign D denotes the diameter of the outer jacket 9 and reference sign d denotes the diameter of the inner jacket 8.

[0039] The dome-shaped region 11 of the deflecting device 1 is furthermore determined by the outer radius R3, which is in the value range 0.01≤R3/D≤0.14. The distance g in the radial direction between the central axis of the deflecting device and the beginning of the curvature with the radius R3 is determined via the relationship 0.13≤g/D≤0.27.

[0040] If this size specification for the geometry is adhered to, the result is a rotationally symmetrical division of the exhaust gas flow into a plurality of partial flows. The central depression facilitates the rotationally symmetrical division of the exhaust gas flow and thus contributes to the improved uniform distribution of flow on the inlet side of the catalytically active matrix 10.

[0041] The first region 11 is spaced from the end of the inner jacket 8 along the axial main flow direction in the flow section 5 by the distance h. The greatest length of the deflecting device along the central axis of the catalytic converter is determined via the value resulting from the dimension h and the radius R3. The value range for h is in the range of 0.016≤h/D≤0.16.

[0042] The width of the region 11 is determined by the dimension g and the radius R3 (2g+2R3) and is greater than the diameter d of the inner jacket 8, wherein d is in the range of 0.36≤d/D≤0.55.

[0043] The deflecting device 1 furthermore also has a second region 12, which adjoins the first region 11 in the radial direction and is formed by an annular depression. The radius R3 is adjoined by the radius R4, which is in the value range of 0.01≤R4/D≤0.11. The depression of the second region 12 primarily serves to produce a constriction of the annular cross section between the end region of the inner jacket 8 and the radially outer partial contour of the deflecting device 1. This constriction ensures an improved flow guidance toward the inlet side of the catalytically active matrix 10.

[0044] The deflecting device 1 also has a third region 13 which is located on the radial outer edge region. The third region is defined by the radius R5, which is in a value range of 0.01≤R5/D≤0.16. The beginning of the outer radius R5 is spaced from the axial end region of the outer jacket 9 or from the inlet side of the catalytically active matrix 10 by the distance j, which is in the value range 0.005≤j/D≤0.15. In the radial direction, the radius R5 is spaced from the central axis of the catalytic converter by the distance i+R4+R3+g.

[0045] From the annular depression with the radius R4 to the third region 13 and the radius R5, the outer contour of the deflecting device 1 increases along the extent i, which is in the value range of 0.05≤i/D≤0.25, by the angle α, wherein the angle α is in the range of 0.5°α25°.

[0046] This gradient of the contour achieves an expansion of the flow cross section, which serves to ensure that the flow forced in the regions 11 and 12 reaches the entire cross section of the catalytically active matrix 10 in the annular outer flow channel 14.

[0047] FIG. 3 also shows the confusor 7 in the inner jacket 8. The confusor 7 has a radial extent k, wherein the value range of k is defined as 0.01≤k/D≤0.11. Furthermore, the confusor 7 has an axial extent m, wherein m is in the value range of 0.015≤m/D≤0.44.

[0048] The confusor 7 thus tapers the inner cross section of the inner jacket 8 over the length m, starting from a radial extent from zero to the value k. The confusor 7 thus protrudes into, and tapers, the flow cross section of the inner jacket 8, as a result of which an improved uniform distribution of flow over the cross section of the catalytically active matrix 10 is achieved.

[0049] The exemplary embodiments in FIGS. 1 to 3 are not of a restrictive nature and serve to illustrate the inventive concept.

[0050] The description of the invention is merely exemplary in nature and, thus, variations that do not depart from the gist of the invention are intended to be within the scope of the invention. Such variations are not to be regarded as a departure from the spirit and scope of the invention.