SE520350C2 - Container arrangement is for incorporation in exhaust gas system of internal combustion engine and comprises outer casing enclosed by tubular body and passage for conducting exhaust gases through container - Google Patents

Abstract

The container arrangement is for incorporation in the exhaust gas system of an internal combustion engine and comprises an outer casing (1) enclosed by a tubular body (4) and a passage for conducting exhaust gases through the container. The passage has a first part extent (17a) located externally around the tubular body, a second part extent (17b) located inside the tubular body and a third part extent (17c) which handles the flow of exhaust gases between the first and second part extents. The third part extent incorporates at least one flow path, which constitutes an extended flow extent for exhaust gases in relation to a straight-line radial flow between the first and second part extents.

Description

520 350 through the container device, which in itself provides a relatively good sound attenuation of low frequency sound. With a suitably shaped passage, a reciprocating fate is provided in the container device with a relatively small flow resistance.

With a suitably shaped passage, the flow resistance need not be much greater than with a conventional container device with a substantially straight continuous passage for the exhaust gases. The introduction of a path of fate which provides an extended flow distance for the exhaust gases in relation to a substantially rectilinear radial flow between the externally located first section and the internally located second section means that the passage is further extended without having to increase the length of the container device. The container device according to the present invention thus provides a long passage for the exhaust gases in a short and compact construction which provides a very good attenuation of low-frequency engine noise.

According to a preferred embodiment of the present invention, the path of fate has a location so as to connect a first space and a second space of the passage.

A basic principle for attenuating low-frequency sound is to create a long exhaust line between two relatively large spaces. An efficient low-frequency muffler with a conventional straight fl fate path between two such spaces for the exhaust gases has a considerable length and thus occupies a large space. With a suitable placement of the path of fate between two such spaces in the container device, a container device is obtained with a short and compact construction which at the same time exhibits good sound-absorbing properties.

According to another preferred embodiment of the invention, the path of fate has a helical stretch. Such a helical path can have a relatively large outer diameter and the path of fate thus obtains a considerable elongation in relation to a substantially rectilinear radial flow distance between the first section which is located outside the pipe and the second section which is arranged inside the pipe. A spiral-shaped path of fate can be made very compact and can be given a main stretch in a radial plane. With such a helical path of fate, the container device can be made very short and compact, even though it comprises a passage for the exhaust gases of a considerable length. A helical fate path also provides a substantially optimal smooth control of the exhaust fate. Thus, the flow losses in the fl fate path can be kept at a low level.

According to another preferred embodiment of the present invention, the path of fate has a helical elongation of 180 ° to 1080 °. A helical path of destiny, for example, needs to extend only one revolution in order to obtain a significant length and provide good sound attenuation. The flow path may have at least one portion with a varying cross-sectional area. The cross-sectional area of the flow path can be varied to obtain a controlled attenuation of the exhaust sound and the flow resistance. The cross-sectional area may, for example, comprise an increasing cross-sectional area in the direction of flow of the exhaust gases. An increasing cross-sectional area in the flow direction reduces the velocity of the exhaust gases. The flow resistance through the path of fate thus becomes low.

According to another preferred embodiment of the present invention, the path of fate is formed by at least one profile having a helical stretch. Such a profile can be elongated and have a length corresponding to the length of the path of fate. The profile thus forms a wall surface at the fl path of fate. The third section may comprise n number of fl paths of fate formed by n number of profiles which are offset 360 ° / n in relation to each other. Advantageously, at least two fl fate paths are used to facilitate the flow of the exhaust gases. Preferably, the two fl pathways have their respective inlets and outlets offset 180 ° relative to each other. This results in a substantially uniform distribution of the exhaust gases between the two fl fate paths. To further facilitate the distribution of the exhaust gases between different fl lanes, the number fl lanes can be further increased. Three or sådana such fl fate flow paths advantageously have their inlets and outlets offset from each other according to the formula above in order to distribute the exhaust gases evenly between the different fl fate paths. In addition, the length of the third section can be increased in this way.

According to another preferred embodiment of the present invention, the exhaust gases are arranged to be passed through the passage in a direction so that they first flow through the first section which is located radially outside the pipe before they flow through the second section which is located inside the pipe. Such a flow direction of the exhaust gases through the passage has fl your advantages. It gives bla. a relatively simple assembly of the constituent parts of the container device, facilitates the design of the path of fate so that an effective sound attenuation is obtained and explains the arrangement of a possible burner at the inlet of the passage. Such a burner is, if necessary, arranged to raise the temperature of the exhaust gases before they reach the particulate filter. In order for the soot particles in the exhaust gases to ignite and burn in the particulate filter, it is required that the exhaust gases have reached a specific temperature.

According to another preferred embodiment of the present invention, said fate path is included in a detachable module. With such a module, the path of fate can be easily mounted and disassembled in the container device. Advantageously, such modules 1 () 15 20 25 520 350 can be manufactured in different designs and sizes. Thus, modules that include fl fate paths of different lengths and numbers can be adapted to internal combustion engines of different types and sizes. Preferably, said detachable module comprises a gable wall of the housing.

Such a module essentially forms a side cover which is very easy to assemble and disassemble.

BRIEF DESCRIPTION OF THE DRAWINGS In the following, a preferred embodiment of the invention is described by way of example with reference to the accompanying drawings, in which: Fig. 1 shows a container device according to the present invention, Fig. 2 shows a section along the line AA in Fig. 1, Figs. 3 shows a section along the line BB in FIG. Fig. 4 shows a section along the line C-C in Fig. 1 and Fig. 5 shows only a module comprising a helical path of fate.

DETAILED DESCRIPTION OF A PREFERRED EMBODIMENT OF THE INVENTION FIG. 1 shows a container device which is arranged to be arranged in an exhaust system for a diesel-powered vehicle. Container device comprises an outer casing 1 which has a substantially cylindrical shape. In Fig. 1, the part of the housing 1 directed towards the viewer is removed to show the parts arranged inside the housing 1. The housing 1 forms a closed outer surface except at the places where an inlet 2 and an outlet 3 are arranged for the exhaust gases. A tube 4 formed in cross-section is arranged inside the housing 1 so that a central axis through the housing 1 and the pipe 4 coincide. The tube 4 has a length so that it extends from a first 5 up to a module M which comprises a second end wall of the housing 1.

The container device comprises exhaust gas cleaning components for purifying the exhaust gases flowing in a passage extending between the inlet 2 and the outlet 3. A first exhaust gas cleaning component in the form of a particle filter 7 is arranged outside the pipe 4.

Fig. 2 shows a section along the line AA in Fig. 1. Here it is shown that the particle filter 7 extends 520 350 30 5 520 350 næf ~: z fi h ". radial stretching so that it completely fills the radial space between the tube 4 and the housing 1. The particle filter 7 comprises elongate channels which have a stretch in a first direction 8. The elongate channels are arranged to direct the exhaust gases through the particle filter 7. The particle filter 7 has The exhaust gases are thus led substantially in the first direction 8 through the particle filter 7. The particle filter 7 comprises stop surfaces 9 which are arranged in suitable places along the length of the elongate channels. channels in the particle filter The soot particles stick to this and are burned in the particle filter 7.

Inside the tube 4 a second exhaust gas purifying component in the form of a catalyst purifier 10 is arranged. The catalyst purifier 10 is arranged radially inside the particle filter 7. The catalyst purifier 10 also comprises elongate channels which are arranged to guide the exhaust gases in a substantially different direction II through the catalyst purifier 10. The catalyst purifier 10 has a constant cross-sectional shape in the flow direction of the exhaust gas purifier 10. is arranged to provide a catalytic purification of the exhaust gases in particular to reduce the content of nitrogen oxides in the exhaust gases flowing through. The particle filter 7 has a larger cross-sectional area than the catalyst purifier 10 in the plane A shown in Fig. 2.

Thus, the exhaust gases obtain an even lower velocity through the particle filter 7 than through the catalyst purifier 10. The flow resistance of the exhaust gases is related to the flow rate. Depending on the stop surfaces 9, the flow resistance of the exhaust gases is substantially greater in the particle filter 7 than in the catalyst purifier 10. By lowering the flow rate through the particle filter 7, the total flow resistance through the passage can be considerably reduced. Preferably, the cross-sectional area of the particle filter 7 is about twice as large as that of the catalyst purifier 10.

A basic principle for attenuating low-frequency sound is to create a long exhaust line between two spaces. An efficient low-frequency muffler with a straight such exhaust line takes up a very large space. Low frequency sound is the dominant part of the sound from an internal combustion engine. The container device comprises sound-absorbing means which are designed according to this basic principle. The container device therefore comprises two profiles 12a, b, which extend in a spiral line format. Each of the probes 12a, b here extends about 1.5 turns, i.e. 540 °. The two profiles 12a, b form wall surfaces of two helical pathways 13a, b, the inlet and outlet of which are offset 180 ° relative to each other. The helical paths 13a, b are arranged inside the module M.

The exhaust gases are led radially inwards, via a third section 17c of the passage which comprises said helical paths 13a, b from a first section 17a of the passage 10 located outside the tube 4 to a second section 17b of the passage which is located inside the tube 4. The space in the passage outside the tube 4 upstream of the fate paths 13a, b forms a first space and the space downstream of the fate paths 13a, b inside the tube 4 forms a second space. By directing the exhaust gases in said helical fl fate paths l3a, b with a radial distance, a long exhaust line is obtained without the container device itself having to be given an elongated shape. The container device, which thus comprises both exhaust gas cleaning components and sound-absorbing components, can thus be made very compact and low-space-consuming, while at the same time exhibiting very good sound-absorbing properties.

A burner 14 can, if necessary, be arranged in the vicinity of the inlet 2 of the container device. The function of the burner 14 is to heat the exhaust gases to a temperature so that the soot particles can be combusted in the particle filter 7. Soot particles normally ignite at a temperature of approximately 600 ° C. In most cases, however, it is difficult to guarantee such a high exhaust temperature even with a burner 14 with a high performance. Therefore, as a rule, the ignition temperature of the soot particles must be lowered. This can be done by converting the various types of nitrogen oxides NOX into nitrogen dioxide NO2. There are mainly two methods to do this. According to a first method, the CRT (Continuously Regeneration Trap) is arranged for a separate oxidation catalyst purifier for this purpose before the particle filter 7 in the direction of flow of the exhaust gases. The soot particles in this case ignite at about 225 ° C in the particle filter 7. According to a second method CSF (Catalytic Soot Filter), the particle filter 7 is coated with a suitable coating material so that the oxidation catalysis from NOX to NO; occurs directly on the surface of the particle filter 7. The soot particles ignite in this case at about 250 ° C. In addition, with various additives in the fuel, a reduced ignition temperature can be obtained at about 350 ° C in a conventional particle 7. an ammonia-bearing substance, for example in the form of urea. Once the ammonia support has been added, it must have time to mix well to optimize the catalyst purifier's reduction of the ammonia and nitrogen oxides of nitrogen gases to nitrogen gas and water. With the elongated helical fl fate paths 13a, b, this is not a problem.

The exhaust gases are led into the container device through the inlet 2. 1Fig. 3 shows a section BB through the container device at the inlet 2. The exhaust gases are led from the inlet 2 to the first section 17a of the passage which has a substantially annular space which extends externally about the pipe 4. The annular space of the first part of the section 17a provides a relatively small flow resistance for the inflowing exhaust gases and gives the exhaust gases a substantially even distribution before they are led in an axial direction outside the pipe 4 towards the particle filter 7. Before the exhaust gases reach the particle filter 7 they are heated as needed. up of the burner 14 to a temperature so that an ignition and combustion of soot particles in the exhaust gases in the particle filter 7 is guaranteed. The exhaust gases are led in the first direction 8 through the elongated channels of the particle filter 7. The stop surfaces 9 which are arranged in suitable places along the elongate channels in the particle filter 7 force the exhaust gases into adjacent elongate channels. Depending on the regeneration system and temperature, the soot particles ignite and burn in the particulate filter 7. The exhaust gases are thus forced to deviate a shorter distance laterally, but they flow mainly in the first direction 8 along a substantially straight line through the particle filter 7. the gases flowing out of the particle filter 7 are substantially free of soot particles.

The exhaust gases flowing out of the particle filter 7 are added to a substance in the form of an ammonia carrier by means of the injection devices 15 before they reach the module M. The module M is shown separately in Fig. 5. The module M comprises a wall surface 18 sealingly abutting the tube 4 at a radial inner area. The wall surface 18 comprises a first inlet 19a where the exhaust gases are led into the first discharge path 13a and a second inlet 19b where the exhaust gases are led into the second discharge path 13b. The helical profiles 12a, b, can be partly seen in the figure, which form the first and second fate paths 13a, b. The module unit M thus also comprises the second end wall 6 and an outer radial area 20 of the housing 1. The module unit M is releasably mounted, straps, in a suitable manner together with the rest of the container device. In the module M the exhaust gases are led radially inwards via one of the two fate paths 1a, b formed by the helical profiles 12a, b. The inlets 19a, b of the two flow paths 1a, b are displaced 180 ° relative to each other so that even distribution of the exhaust gases is obtained between the two fl lanes l3a, b. between the first section l7a which is located outside the pipe 4 and the second section l7b which is located inside the pipe 4. The helical fl pathways l3a, b provide an elongated exhaust line connecting two spaces of the passage so that an effective sound attenuation of low frequency sounds from the diesel engine is obtained. . The elongated ban fatal paths l3a, b also supply a required mixing distance for 10 15 20 25 30 520 350 .. Hr »J» t; the ammonia carrier so that it has time to be distributed substantially uniformly in the exhaust gases. The exhaust gases are given a relatively soft deflection during transport in the helical fl fate paths l3a, b, which reduces the flow resistance. In the helical fl paths of fate 13a, b a flow is obtained in a plane which is substantially perpendicular to the first 8 and other 11 flow directions of the exhaust gases. The exhaust gases flowing out of the helical paths are led into the pipe 4. The exhaust gases from the fate paths 13a, b are received in the centrally located space 21 of the module M before the exhaust gases are led into the pipe 4 and towards the catalyst cleaner 10. When flowing inside the pipe 4 the exhaust gases reach the catalyst cleaner 10, they flow into its elongated channels. The elongate channels allow a flow of the exhaust gases in the second flow direction II which is parallel to and opposite to the first flow direction 8. In the catalyst purifier 10 the exhaust gases content of nitrogen oxides and ammonia is reduced to nitrogen gas and water. Thereafter, the exhaust gases substantially liberated from soot particles and nitrogen oxides flow out through the outlet 3. The outlet 3 comprises a well-rounded decreasing shape which connects the pipe 4 to a narrower pipe of the exhaust system. However, the narrower tube 4 is not shown in the Figures. The former 3 of the outlet 3 means that the exhaust gases also here obtain a very small flow resistance.

The flow path 13a, b is thus included in a detachable separate module M which can be easily mounted and disassembled. Thus, the end wall 6 and the helical fl fate paths l3a, b can be mounted as a unit. Such modules M can be manufactured in different designs and sizes. Thus, modules M comprising fl paths of fate of different numbers, lengths and cross-sectional areas can be mounted in the container device, e.g. depending on the type and size of the internal combustion engine. The module can be mounted with straps.

The invention is in no way limited to the described embodiment but can be varied freely within the scope of the claims. For example, the fate paths do not necessarily have a helical distance, but they can have a substantially arbitrarily shaped curved distance so that an extended transport distance of the exhaust gases is obtained in relation to a substantially rectilinear radial distance. The exhaust gases can alternatively be led in an opposite direction so that they first flow through the pipe 4 on the inside before they are led radially outwards, via the fate paths 13a, b, to a final flow outside the pipe 4. In such a case the particle filter 7 is arranged inside the pipe 4 and the catalyst cleaner The casing 1, the exhaust gas purifying components 7, 10, and the pipe 4 do not necessarily have to have a circular cross-sectional shape, but they may have a substantially good, in-shape shape. Likewise, the tube 4 does not have to be centrally arranged inside the housing 1, but it can have a substantially arbitrary but functional location.

Claims (11)

10 15 20 25 520 3501 10 .U »i Patentkrav A container device arranged to be arranged in an exhaust system of an internal combustion engine, the container device comprising an outer housing (1), a tubular body (4) enclosed by said housing (1) and a passage for guiding the exhaust gases through the container device, said passage comprising a first section (17a) located outside the tubular body (4), a second section (17b) located inside the tubular body (4) and a third section (17c) providing a flow of the exhaust gases in a radial direction between the first section (17a) and the second section (17b), characterized in that the third section comprises at least one fate path (13a, b) which provides an extended flow distance for the exhaust gases relative to a substantially rectilinear line. radial flow between the externally located first section (17a) and the internally located second section (17b). Container device according to claim 1, characterized in that the fate path (13a, b) has a location so that it connects a first space and a second space of the passage. Container device according to Claim 1 or 2, characterized in that the fate path (13a, b) has a helical extension. Container device according to Claim 3, characterized in that the fate path (13a, b) has a helical elongation of 180 ° to 1080 °. Container device according to one of the preceding claims, characterized in that the path of fate (13a, b) has at least one portion with a varying cross-sectional area. Container device according to one of the preceding claims 3-5, characterized in that the path of fate (13a, b) is formed by at least one profile (12a, b) which has a helical extension. Container device according to any one of the preceding claims, characterized in that said third section (17a) comprises n number fl paths of fate (13a, b) formed by n number of profiles (12a, b) which are offset 360 ° / n relative to each other. Container device according to claim 7, characterized in that n is greater than or equal to 2,520,350 ll Container device according to one of the preceding claims, characterized in that the exhaust gases are arranged to be passed through the passage in one direction so that they first flow through the first section (17a) before flowing through the second section (17b). 10. l0. Container device according to any one of the preceding claims, characterized in that said des odes path (13a, b) is included in a detachable separate module (M). 11. ll. Container device according to claim 10, characterized in that said detachable module (M) comprises at least one end wall (6) of the housing (1).