WO2007076978A2

WO2007076978A2 - Particulate filter assembly

Info

Publication number: WO2007076978A2
Application number: PCT/EP2006/012466
Authority: WO
Inventors: Herbert Stieglbauer
Original assignee: Ark-Holding Ag
Priority date: 2005-12-22
Filing date: 2006-12-22
Publication date: 2007-07-12
Also published as: WO2007076978A3

Abstract

Disclosed is a particulate filter assembly (10) for filtering exhaust gases of an internal combustion engine, especially a diesel engine, comprising an inlet and an outlet. At least one particulate filter (4) is disposed between the inlet and the outlet in the flow path of the exhaust gases. The exhaust gases are conducted inside a pipe that is provided with a first section (11) in which the exhaust gases are conducted substantially towards the outlet. Said pipe is provided with a second section (12) in which the exhaust gases are conducted essentially towards the inlet. In order to very quickly obtain a sufficiently high operating temperature of the assembly to prevent the filter from being fully loaded, the pipe is further provided with a third section (13), in which the exhaust gases are conducted substantially towards the outlet.

Description

particulate filter assembly

The present invention generally relates to the field of aftertreatment of exhaust gases. More particularly, in a first aspect, the present invention relates to a particulate filter assembly for filtering exhaust gases of an internal combustion engine, particularly a diesel engine, having an inlet and an outlet, wherein at least one particulate filter is disposed in the exhaust gas flow path between the inlet and the outlet, the exhaust gases in a conduit wherein the conduit has a first portion in which the exhaust gases are directed substantially in the direction of the outlet, wherein the conduit further comprises a second portion in which the exhaust gases are guided substantially in the direction of inlet. According to a second aspect, the present invention relates to a particulate filter arrangement for filtering exhaust gases of an internal combustion engine, in particular a diesel engine, having an inlet and an outlet, wherein in the flow path of the exhaust gases between the inlet and outlet at least one deflecting element is provided for changing the direction of the exhaust gas flow. According to a third aspect, the present invention relates to a particulate filter arrangement for filtering exhaust gases of an internal combustion engine, in particular a diesel engine, with an inlet and an outlet. According to a fourth aspect, the present invention relates to a method for filtering exhaust gases of an internal combustion engine, in particular a diesel engine, by means of a particulate filter assembly having an inlet and an outlet.

Exhaust gases produced by internal combustion engines or industrial processes generally contain potentially harmful components such as hydrocarbons (HC), carbon monoxide (CO), nitrogen oxides (NO _x ), and especially particulate matter such as particulate matter. Such ingredients must be converted into harmless or at least less hazardous ingredients to reduce the amount of harmful substances released to the environment. Conventionally, therefore, the exhaust gases are subjected to a catalytic treatment and / or a filtering process. Basically, catalysts are also known in the prior art, which serve to remove harmful components, such as SO _x and NO _x , from the exhaust gases. In addition, a catalyst also has the effect of increasing the temperature of exhaust gases, which in turn can aid in the decomposition of soot particles.

In diesel engines there is basically the problem that in the exhaust gases in particular soot particles (CO) are included. In order to remove these from the exhaust gases, particle filters are known. The soot particles are formed in particular by the addition of additives to the fuel. Although the particulate filter can remove the soot from the exhaust gases, it has the problem that it is clogged when too much particulate matter is stored in it. At a correspondingly high temperature (above approximately 400 ° C), however, the CO is decomposed, and therefore a fully charged filter can regenerate at such a temperature. It is therefore of particular importance that the temperature of the exhaust gases before or during filtering is as high as possible, and in particular that the temperature in the filter is as high as possible, so that the "ignition temperature" is reached.

It is of particular importance that the installation space of the entire particle filter arrangement as well as the particle filter itself is as small as possible, and that a high temperature is reached as quickly as possible, so that the self-ignition effect starts, otherwise the filter clogs too fast and, for example, engages Motor vehicle is no longer operational. In particular, in a driving style in which one drives only a few minutes daily ("morning roll bring"), the filter can be more and more charged with soot particles, without a sufficiently high temperature is achieved for burning the soot, so that after some time The motor vehicle is therefore no longer operable and the filter must be replaced, which is why it is particularly important how fast a required high temperature is reached. These are problems known in the prior art which occur with the cold start of an engine (with a corresponding cold start) Catalyst) and with "cold exhaust gases", as they emerge from a diesel engine, are connected.

In principle, the temperatures of the exhaust gases depend on the type of diesel engine used and of course in the case of motor vehicles respective type. Normally in a motor vehicle the temperatures of the exhaust gases should be between 150 and 210 ° C. In a naturally aspirated engine, the temperatures of the exhaust gases are about 280 ° C and in a turbocharger at 350 ° C. The problem of full loading a required particulate filter is therefore much less serious in a naturally aspirated engine or a turbocharger, since the outlet temperatures of the exhaust gases are already high. For normal diesel engines, the clogging of the particulate filter in practice is a serious problem for which the prior art does not provide a sufficient remedy.

The invention is therefore based on the object to avoid the disadvantages of the prior art, and in particular a particle filter assembly of the type mentioned in such a way that adjusts particularly quickly a sufficiently high operating temperature of the arrangement or of the particulate filter to avoid full loading of the filter.

According to a first aspect of the present invention, this object is achieved in a particulate filter arrangement of the type mentioned above in that the conduit further comprises a third section in which the exhaust gases are guided substantially in the direction of the outlet.

A particular advantage of the embodiment of the invention is that due to the resulting through the three sections so-called "folded" flow path of the exhaust gases results in an overall very compact particulate filter assembly having a long distance for the exhaust gases, so that the residence time of the exhaust gases in the on In particular, if the temperature increase of the exhaust gases serving components, such as catalysts, are arranged in the fluid path, the long flow path also allows corresponding locations for the arrangement of such components, the exhaust gases reach high temperatures, which together with the long residence time correspondingly favorable effect on the equilibrium temperature resulting in the entire arrangement or also on the speed with which such equilibrium temperature is established. Preferably, the exhaust gases flow through the first, second and third portions of the conduit in sequence. The first, second and third sections of the line need not necessarily follow each other directly, but it may also be arranged corresponding intermediate sections. In this embodiment, only the first section, then the second section and finally the third section of the line are run through in the sequence first. This means that the exhaust gases are initially guided substantially in the direction of the outlet, are later guided substantially in the direction of the inlet, and thus in the opposite direction, and finally guided again essentially in the direction of the outlet. A folding of the exhaust gas path preferably takes place substantially in the manner of a degenerate "Z." This can be seen clearly from the upper and lower halves of the longitudinal section illustrations of FIG.

Advantageously, at least one particle filter is arranged in the first, second or third section of the line. Here, the arrangement of the at least one particulate filter in a line section is preferred in which the exhaust gases have already been brought to a sufficiently high temperature, so that a full loading of the filter is no longer possible or the entire filtering process is much more effective due to the elevated temperature.

In order to further improve the result of the exhaust gas aftertreatment, it is preferable for a further particle filter to be arranged in the first, second or third section. The provision of a further particulate filter increases the efficiency of the filtering and preferably also the further particulate filter is arranged in a section other than the line as the at least one particulate filter.

In terms of construction, but also to reduce the manufacturing cost is preferred that the at least one particulate filter and the further particulate filter are integrally formed as a filter monolith. If the filter monolith has corresponding non-interconnected channels for carrying the exhaust gases, gasket (s) may be provided by corresponding ones at the inlet and / or outlet end of the filter monolith. ensure that even in the filter monolith, the different line sections are separated from each other.

Further, it is preferred that between the first and the second portion and the second and the third portion regions of the conduit are provided, in which the flow direction of the exhaust gases is substantially reversed. Advantageously, a catalyst is arranged in at least one of the regions. In addition to the actual effect of a catalytic converter, namely that of a catalytic pretreatment, the catalyst also serves to increase the temperature of the exhaust gas flow as well as the entire arrangement, which assists the filtering process and avoids the filter becoming full. The appropriate design of the exhaust gas flow path creates opportunities to install one or more catalysts in the flow path. This can be done so that after passing through the catalyst, the exhaust gases still remain in the arrangement and thus the increased temperature has a positive effect on the overall temperature of the arrangement positive.

Structurally, it is preferable that the first, second and third portions of the conduit are concentric with each other. A practically meaningful realization provides that one of the first, second and third sections has the shape of a cylinder and the two other sections have the shape of a circular ring cylinder or pipe. Advantageously, one of the first, second and third sections is formed by the interior of a first tube and thus has a substantially cylindrical shape (circular in cross-section). For the two further sections, two further tubes are provided, which are essentially concentric with the first tube and have two different and both larger diameters than the first tube; one of the two further sections is then in the space between the outer wall of the first tube and the inner wall of the second tube (smaller diameter than the third tube) and the second of the two further sections is in the space between the outer wall of the second tube and the inner tube. wall of the third tube (larger diameter than the second tube) is formed. The two further sections therefore have a circular ring shape in cross section. This results in a particularly compact design of the first, second and third tion sections, as this no space is lost, and the arrangement consisting of the three line sections has the overall shape of a cylinder.

In a preferred embodiment of the present invention, the following is provided: Känning a soot particulate filter with exhaust gas recirculation within the filter system or arrangement, in particular incl. Or preferably with two times oxy regeneration catalyst and preferably double filtering the flue gases.

A particularly good heat exchange between the exhaust gas flows of the arrangement results from the fact that the first and second sections and / or the second and third sections and / or the first and third sections of the duct are separated by a common wall.

The particle filter arrangement advantageously has a distribution and deflecting element, which leads a first exhaust gas stream coming from the inlet to the first section of the pipe and deflects a second exhaust gas stream arriving from the second section of the pipe to the third section of the pipe. The distribution and deflection element therefore has a dual functionality. It is preferably realized by a star-shaped deflection, in which the various exhaust gas streams cross several times without these mixing. The through or cross exhaust system causes the distribution and deflection element is heated, and also depends on the catalysts used and thus serves as a heat exchange element. This formally precombustion of soot particles take place before they enter the actual particle filter. As a result, the space requirement of the arrangement is reduced enormously. By the Umlenkfunktionalität even a purified exhaust gas can be passed through a particulate filter again to realize further catalytic treatment and Filterfünktionen.

Furthermore, it is preferred that the distribution and deflection element for guiding the first and second exhaust gas streams have respective channels, wherein at least a part of the outer wall of the channel of the first exhaust gas flow forms the inner wall of the channel of the second exhaust gas flow. Advantageously, the particle filter arrangement has at least the following sections in the direction from the inlet to the outlet: a first section which has a distribution and deflection element for the exhaust gases; a second section having at least one particulate filter; and a third portion having a deflecting element for the exhaust gases. In this regard, the overall particulate filter assembly is asymmetrical in that the first portion has a distribution and deflection member, while the third portion has only a deflector.

Advantageously, the first, second and third sections of the conduit are arranged in the second section of the particle filter arrangement.

It is further preferred that the particulate filter arrangement has a catalyst arranged in the flow direction of the exhaust gases directly behind the inlet and / or in front of the first section of the pipe.

To further increase the filtering efficiency is preferred that the particulate filter assembly comprises a arranged in the flow direction of the exhaust gases immediately upstream of the outlet and / or behind the third section of the line particulate matter.

According to a second aspect of the present invention, this object is achieved in a particulate filter arrangement of the type mentioned above in that the deflecting element has a catalyst.

A particularly preferred practical realization results from the fact that the deflecting element is designed as a substantially U-shaped channel for the exhaust gas flow, in which at least partially the catalyst is arranged. This can be clearly seen in the upper and lower half of the longitudinal sectional views of FIGS. 1a and 2a. By the substantially U-shaped channel, a deflection is realized by about 180 degrees, ie a folding of the exhaust gas flow path, which serves to extend the exhaust flow path, but at the same time the entire design is kept compact.

It is further preferred that the catalyst is formed from a wire mesh.

According to a third aspect of the present invention, this object is achieved in a particulate filter assembly of the type mentioned above in that the particulate filter assembly comprises a distribution and deflection element, which distributes a first exhaust gas flow substantially while maintaining the direction in the arrangement and a second, in flowing in substantially opposite direction flowing exhaust gas flow at an angle, preferably in about 180 degrees, with the two exhaust gas streams do not mix.

According to a fourth aspect of the present invention, this object is achieved in a method of the type mentioned in that the flow direction of the exhaust gases between the inlet and outlet at least twice by about 180 degrees is deflected.

Further preferred embodiments of the invention are disclosed in the dependent patent claims.

The invention, as well as other features, objects, advantages and applications thereof, will be or will be explained in more detail below with reference to a description of preferred exemplary embodiments with reference to the accompanying drawings. In the drawings, the same reference numerals designate the same or corresponding elements. In the present specification, the term "flow direction" of the exhaust gases is used, which of course is understood to mean the average flow direction of the exhaust gases, it being clear to a person skilled in the art that individual particles of the exhaust gases are moving in their direction of movement from the central or the predominant flow direction (in FIG The terms "before" and "behind" and the like are used to refer to relative arrangements with respect to the main flow direction, generally from the inlet to the outlet must be indicated. All described and / or illustrated features alone or in any meaningful combination form the subject matter of the present invention, regardless of their summary in the claims or their dependency. In the drawings show:

1 a is a schematic representation in longitudinal section to explain a first exemplary embodiment of a particle filter arrangement according to the invention;

FIG. 1b shows a schematic representation in a longitudinal section of a part of FIG. 1a in further detail for a more detailed explanation of the particle filter arrangement according to the invention according to the first exemplary embodiment;

1c shows a schematic representation in a plan view of the part shown in FIG. 1b in further detail for a more detailed explanation of the particle filter arrangement according to the invention according to the first embodiment;

2a is a schematic representation in longitudinal section to explain a second embodiment of a particulate filter arrangement according to the invention;

2b is a schematic representation in longitudinal section of a portion of Fig. 2a in further detail for further explanation of the particulate filter assembly according to the invention according to the second embodiment;

2c is a schematic representation in a plan view of the part shown in FIG. 2b in further detail for a more detailed explanation of the invention

Particle filter assembly according to the second embodiment; and

Fig. 3 is a schematic representation in longitudinal section to explain a third

Embodiment of a particulate filter assembly according to the invention.

With reference to the sectional views of FIGS. 1 a to 1 c, a first exemplary embodiment of a particle filter arrangement 10 according to the invention will be described below With regard to its structure and function explained in more detail. FIG. 1a shows a highly schematic representation of a longitudinal sectional view of the particle filter arrangement 10 according to the invention. The particle filter arrangement 10 according to the invention has a direction of flow in the main flow direction of the exhaust gases (in the direction from the inlet to the outlet, ie from left to right in FIGS Inlet section a, a filter stalk section b, a front deflecting section or first section c (indicated only very schematically in Figure la), a filter section or second section d, a rear deflecting section or third section e, a filter post section f and an outlet section g, all are formed in a common housing 2, on. The particulate filter assembly 10 is connected via the inlet section a, for example, with an engine (not shown) of a motor vehicle, from which in particular exhaust gases containing soot particles via lines (not shown) are fed to the inlet section a of the particulate filter assembly 10. Via the outlet section a, the particulate filter assembly 10 is connected to an exhaust (not shown). Of course, various other components, such as a catalyst, may be provided between the engine and the inlet section a. Likewise, between the outlet section g of the particulate filter assembly 10 and the exhaust various other components, such as a carburetor can be arranged. The particle filter arrangement 10 according to the invention is therefore inserted into the exhaust system at a suitable location, for example by a welded connection or a flange connection, and serves to clean the exhaust gases in order to comply with or even fall below the required limit values for the degree of purity of the exhaust gases. The particulate filter assembly 10 is generally symmetrical about a central axis (not shown). The inlet section a has a tubular cross-section with external diameter D). The filter stem section b arranged in the flow direction of the exhaust gases directly behind the inlet section a likewise preferably has a tubular cross-section with a slightly enlarged outside diameter Di '> Di in the outside diameter. The front deflecting section c immediately adjacent to the filter stem section b in the flow direction of the exhaust gases b first extends from the outer diameter Di 'to an outer diameter D _{2 which is} constant over the further length of the section c. Over the area of the particle filter assembly 10 with a constant outer diameter D ₂ , the housing 2 inside thereof a thermal insulation 3 on. The filter section d, the rear deflecting section e and the filter replenishment section f have the constant outer diameter D ₂ . Between the filter replenishment section f and the outlet section g, a step is formed so that the outlet section g again has the outer diameter Di. The inner structure of the front deflecting section c is for better clarity in Fig. Ia only indicated and shown in more detail in Figs. Ib and Ic. The front deflection section c has the function of forwarding the exhaust gas arriving from the inlet section a and the filter stem section b to corresponding regions, more precisely to a region offset radially to the middle, of the filter section d. In addition, the front deflecting section c has the function of certain areas, more precisely of a central region of the filter section d flowing in the opposite direction, ie, flowing back (without mixing with the newly supplied exhaust gases), exhaust gases in their direction to reverse in about 180 degrees, that is, to divert such that they again flow in the main flow direction from the inlet section a to the outlet section g, and to introduce them again into the filter section d of the particle filter arrangement 10 according to the invention, albeit in a radially outermost region. Because of these functionalities of the first section c of the particle filter arrangement 10 according to the invention, this can also be referred to as the front distribution and deflection section c. The primary function of the filter section or second section d of the particle filter arrangement 10 according to the invention is the filtering of the exhaust gases. The third or rear deflection section e serves to distribute the exhaust gas streams supplied by a radially offset annular region into an inner cylindrical region of the filter section d, the flow direction being reversed by approximately 180 degrees. In the process, a catalytic treatment of the exhaust gases takes place. The filter post-section f provides for deflecting the exhaust gases two times 90 degrees from the radially outer region back to the central region of the filter outlet section g, effectively maintaining the main flow direction from the inlet to the outlet, again with catalytic treatment at one to the central axis is provided in approximately perpendicular guide portion for the exhaust gases. In the following, the construction of the particle filter arrangement 10 according to the invention will now be explained in more detail in further detail. In the filter stem portion b with the outer diameter D ₁ ', a catalyst 6 is arranged, which can also be referred to as a first precatalyst, since it is upstream of the actual filtering. The filter section d is formed substantially symmetrically with respect to the central longitudinal axis of the particle filter arrangement 10 and has a central cylindrical particle filter 4, which extends in the radial direction from the central axis to about one third of half the outer diameter D ₂ and approximately in the longitudinal direction Half the length of the formed by the sections c, d, e and f part of the Partikelfil- teranordnung 10 extends. Arranged around the cylindrical particle filter 4 is an annular particle filter 14, wherein both particle filters 4, 14 are separated by a common annular wall 17. Both particulate filters 4 and 14 are preferably silicon carbide (SiC) particulate filters. The annular particle filter has a thickness which corresponds approximately to a third of half the outer diameter D _{2 of} the second filter section 2. The preferred practical realization of the cylindrical particle filter 4 and the annular particle filter 14 is preferably carried out by a monolith having a plurality of longitudinally extending and non-interconnected channels for filtering, wherein by a at the inlet portion a end facing the circular Borderline see between the filters 4, 14 provided seal 15 is a functional separation of the monolith in the two filters (sections) 4, 14 is provided. The common wall 17 is formed by the plurality of outer walls of the outermost channels of the filter 4. Radially outside of the particulate filter 14, an annular channel is formed, which inwardly from an outer wall 18 of the filter 14 with formed therein seal and / or thermal insulation 19 and outwardly from an inner wall of the housing 2 in the region of the sections c, d, e and f is limited. In this channel, no exhaust gas treatment element is arranged, since this channel mainly serves to transport the exhaust gas flow in the direction from the inlet to the outlet. Between the filter stem section b and the filter section d, the deflection section c is arranged, which in the exemplary embodiment has four channels for directing exhaust gases arriving from the filter stem section b through an annular second primary catalytic converter 16 into the outer particle filter 14. In Fig. Ia are two Channels recognizable, which are formed by the inner wall 7 and the outer wall 9. The second precatalyst 16 has substantially the same inner diameter as the particle filter 14. The outer diameter of the precatalyst 16 also corresponds substantially to that of the particulate filter 14, and more precisely to that of the wall 18, which is arranged around the particulate filter 14 around. Further, the particulate filter assembly has a third cylindrical (pre-) catalyst 26 at an outlet end of the filter section d, and more specifically in the rear deflecting section e, whose outer diameter is approximately that of the particulate filter 14 and the wall 18 (and thus also that of the second precatalyst 16). In addition to the actual catalyst function of this annular catalyst for deflecting the exhaust gas flow is used by about 180 degrees from the outer particle filter 14 in the central particle filter 4. According to the invention, the exhaust gases in the filter section d are guided in different directions within the particle filter arrangement 10. More specifically, in the particulate filter assembly 10, a conduit is formed which has three sections in the filter section d of the particulate filter assembly 10. This exhaust pipe has in the particulate filter 14 a first (line) section 11 in which the exhaust gases flow in the direction from the inlet to the outlet (in the drawing from left to right). Furthermore, the exhaust pipe in the central particle filter 4 has a second (pipe) section 12 in which the exhaust gases flow substantially in the direction from the outlet to the inlet. On the outside, the pipe has a third (pipe) section 13, the third pipe section 13 corresponding to the radially outer annular channel, and in which the flow direction of the exhaust gases is again from the inlet to the outlet. The first, second and third line sections are traversed by the exhaust stream in this order. According to the terminology of the present application, the front and rear ends of the pipe sections 11, 12 and 13 coincide with those of the filter section d. Behind the rear deflection section e, the filter replacement section f is provided, which has an annular aftercatalyst 36 whose inner diameter corresponds to that of the particle filter 14 and whose outer diameter corresponds to that of the third line section or channel 13. Since the catalyst 36 downstream of the actual filtering, this is referred to as a post-catalyst. By the Nachkatalysator 36 and a along its Innenum- fang mounted, annular perforated plate 37, the exhaust gases are directed into the outlet section g, in which they emerge centrally along the central axis of the particle filter assembly 10. More specifically, the exhaust gases are deflected at entry into the post-catalyst 36 by about 90 degrees and again deflected at about 90 degrees when exiting the post-catalyst 36. The postcatalyst 36 may optionally be followed by a fine dust filter (not shown), which is arranged both in the filter replenishment section f, but can also protrude into the tubular outlet section g.

The exhaust gases flowing through the inlet section a and the filter stem section b and pretreated by the catalyst 6 are distributed by the deflecting section c of the particle filter arrangement 10 according to the invention through the second precatalyst 16 into the first line section 11, in which they are filtered by the particle filter 14. After flowing through the first line section 11, the exhaust gases are not only catalyzed by the catalyst 26, which extends over the outlet-side ends of the first and second line sections 11, 12, but also deflected by about 180 degrees, so that after passing through the first line section 11th and the catalyst 26, the exhaust gases in the line section 12 of the particulate filter assembly 10 back to flow toward inlet section a due to the deflection of the catalyst 26 and are filtered therein by the main particle filter 4. The exhaust gases flowing back in the second line section 12 therefore pass again into the deflection section c of the particle filter arrangement 10, in which they are again deflected by approximately 180 degrees, in such a way that no mixing takes place with the exhaust gas streams arriving from the inlet section a. In this case, the exhaust gas streams arriving from the second line section 12 are guided into the third line section 13 arranged radially on the outside. In the third line section 13, the exhaust gases flow again in the direction from the inlet to the outlet. After passing through the third line section 13, the exhaust gases are aftertreated by the postcatalyst 36 before they exit via the outlet section g in the direction of the exhaust.

The exhaust gases therefore enter the particle filter arrangement 10 through the inlet section a and are pretreated by the precatalysts 6, 16. According to one in the state known technology, the precatalysts 6, 16 already provide for an increase in the temperature of the exhaust gases, so that they have an elevated temperature on entry into the first line section 11 of the particle filter assembly 10. In this section, the particulate filter 14 provides for filtering the exhaust gases primarily with respect to soot. As explained above, the filtering is much more effective due to the increased temperature of the exhaust gases. After passing through the first line section 11, the exhaust gases are deflected by the catalyst 26 in its flow direction by 180 degrees in the centrally disposed second line section 12. The arranged at the rear end side of the two line sections 11 and 12 catalyst 26 ensures not only for a reversal of the flow direction and for forwarding from the first line section 11 in the second line section 12, but it finds - according to the catalysts 6, 16- another Temperature increase of the exhaust gases instead. In the second line section 12, the exhaust gases flow from the filter section d of the particle filter arrangement 10 back into the deflection section c. In the particulate filter arrangement 10, the finally filtered exhaust gases delivered by the second line section 12, without mixing with the exhaust gases arriving from the inlet section a, are again reversed in the outermost region of the filter section d of the particulate filter arrangement 10, and more particularly in FIG the third line section 13, in which no exhaust aftertreatment means is provided, passed. After flowing through the post-catalyst 36, the exhaust gases exit from the outlet section g in the direction of the exhaust. In the illustrated in FIGS. Ia to Ic first embodiment of a particulate filter assembly 10 according to the invention therefore takes place a double deflection of the exhaust gases in about 180 degrees. On the one hand, this double deflection ensures that the exhaust gases, when emerging from the particle filter arrangement 10 according to the invention, again flow in the original flow direction from the inlet section a to the outlet section g. A heating of the exhaust gases takes place in particular on the catalysts 6, 16 and 26. Due to the countercurrent effect (the first, second and third line sections 11, 12 and 13 are in thermal contact with each other by a common wall) therefore finds a heating of the colder gas streams through the heat exchange with in the arrangement, in particular by the proposed catalysts, already heated exhaust gases instead. In particular, also by the deflecting section c of the particle according to the invention Kefilteranordnung 10 provided deflection of the filter section d, and more precisely from the Leirungsabschnitt 12, exiting and re-entering the third line section 13 of the second filter section 2 exhaust streams are directly from the inlet section a in the first line section 11 of the filter section d of the particulate filter assembly 10 entering exhaust gas streams already heated so that they have a much higher temperature, so that a Volladen the particulate filter 4 and 14 can be largely avoided and the entire filter process is thus much more efficient. The entire particle filter assembly 10 is brought by the inventive design in a much shorter time to a correspondingly high temperature. It has been found by experiments that the temperature setting in the particle filters 4 and 14 is sufficient for the almost complete vaporization of the soot particles. In particular, the exhaust gases, depending on the respective starting temperature, which is determined not least by the nature of the engine, even before entering the particulate filter 4 and 14 at such a high temperature that almost no soot particles are more contained in the exhaust gases. The temperature increase achieved according to the invention is also so great that a fine dust filter can be omitted.

The inner structure of the deflection section c of the particle filter arrangement 10 will be explained in further detail with reference to FIGS. 1 b and 1 c. It should be noted that various components shown in Fig. Ia have been omitted for the sake of clarity. This applies in particular to the two precatalysts 6 and 16. It is apparent from a synopsis of FIGS. 1 b and 1 c that a total of four channels with inner wall 7 and outer wall 9 are arranged in a star-symmetrical manner with respect to the central axis, namely by an angle of approximately 90 ° Grad offset to each other, which deliver the exhaust gases supplied from the filter stem portion b in the annular space in which the precatalyst 16 is arranged. Furthermore, FIGS. 1 b and 1 c show that the exhaust gas streams entering the deflection section c from the second line section 12, in which the particle filter 4 is located, again enter the aforementioned channels, formed by the inner wall 7 and the outer wall 9 , Disposed channels are deflected by about 180 degrees and enter the radially outer third line section 13 of the filter assembly d. Due to the offset arrangement of the ducts for exhaust gas injection and recirculation, the inner part (with the exception of the outer casing 2) of the particulate filter assembly 10 may also be referred to as a "star." The front deflector section c therefore has a diverting and distribution functionality to redistribute or deflect in its direction the incoming exhaust gas stream into an annular region arranged around the center axis of the arrangement (the first line section 11 with particle filter 14 arranged therein), and the deflecting section c also serves to move out of the central region of the arrangement (That is, the second line section 12 with arranged therein particulate filter 4) delivered exhaust gas flows in the radially outer channel with the line section 13 formed therein without an exhaust aftertreatment serving element or for this purpose by 180 degrees or reverse.

A second exemplary embodiment of the particle filter arrangement 10 'according to the invention will be explained in more detail below with reference to FIGS. 2 a to 2 c. The second exemplary embodiment of the particle filter arrangement 10 'according to the invention shown in FIGS. 2 a to 2 c is generally similar to the first exemplary embodiment already described in connection with FIGS. 1 a to 1 c. In the following, therefore, only the differences to the already described first embodiment will be discussed. The particulate filter assembly 10 'according to the second embodiment does not have a filter post-portion f. The outlet section g 'immediately adjoins the rear deflection section e'. The catalyst 26 'of the particulate filter assembly 10', unlike the catalyst 26 of the particulate filter assembly 10 is annular and formed symmetrically to the central axis of the Partikelfϊlteranordnung 10 '. The inner diameter of the catalyst 26 'corresponds to D ₁ and the outer diameter of the annular catalyst 26' corresponds approximately to that of the particulate filter 14 '. More specifically, the size and arrangement of a perforated plate 37 'extending along the outer periphery of the catalyst 26' corresponds to the outer wall 18 'of the particulate filter 14'. The catalyst 26 'is sealed inwardly by an extended housing wall of the outlet section g' opposite it. For this purpose, a seal 15 'opposite seal 15' is further provided at the outlet end of the particulate filter 4 '. These structural differences provide for a different flow pattern of the exhaust gases in the Particle filter assembly 10 'of the second Ausfϊihrungsbeispiels in comparison to the particle fϊlteranordnung 10 of the first exemplary embodiment. The course of the exhaust gas flow is initially as in the above-explained first exemplary embodiment. After the exhaust gases have entered through the inlet section a 'and the filter stem section b ¹ , the exhaust gases from the deflecting element 10', in which the catalytic converter 16 'is arranged, are led into the first line section 11', which forms part of the filter section d ', and in which the particulate filter 14 'is arranged. Immediately after emerging from the line section 11 ', the exhaust gases enter the catalyst 26' and are then, in contrast to the above-explained first exemplary embodiment, deflected outwardly into an annular, radially outwardly provided channel. In this outer channel, the exhaust gases flow in the opposite direction, ie from the outlet to the inlet, which can be clearly seen in FIGS. 2a to c by the exhaust gas flow indicated by arrows. The second line section 12 ', which corresponds to the region of the outer radial channel in the region of the filter section d', is therefore arranged completely outside in this embodiment. From the filter section d ', the exhaust gases enter the deflection section c' again, without mixing with the exhaust gas streams newly supplied by the filter stem section b '. Although no mixing of the exhaust gas streams takes place, however, a heat exchange effect also occurs in the deflection section c 'as in the first exemplary embodiment, since the exhaust gases supplied from the filter section d' are at a substantially higher temperature as they pass through the catalytic converters 16 'and 26'. and compared with the exhaust gas streams entering from the primary catalytic converter section b 'into the deflecting section c'. Via common walls of the otherwise separate channels, heat exchange, ie heating of the exhaust gas streams entering into the catalytic converter 16 'or of the surrounding components or components is achieved, which makes the filtering process more efficient and, in particular, avoids filing of the filter. By the deflection element c ', the exhaust gas streams from the second line section 12' in the centrally arranged in this embodiment third Leirungs- section 13 'passed, in which the Partikelfllter 4' is located. The exhaust gas streams are already before entering the particle filter 4 'in the desired outlet direction, ie in the direction from the inlet to the outlet. After passing through the particle filter 4 ', the exhaust gases pass through the sections extending over the sections e' and g ' Outlet pipe with outer diameter D ₁ from the particulate filter assembly 10 'from. The particulate filter assembly 10 'is compared to the particulate filter assembly 10 due to the omission of the post-catalyst 36 is more compact and has the advantage of faster heating, as the outgoing from the particulate filter assembly 10' Abgasström Ström is guided centrally over a relatively long time in the arrangement, which positively affects the equilibrium temperature established throughout the assembly.

In the schematic illustrations of FIGS. 2b and 2c, the deflection section c 'of the particle filter arrangement 10' of the second exemplary embodiment is shown in further detail. Basically, this construction corresponds to that of the construction of the deflecting element c of the particle filter arrangement 10 of the first exemplary embodiment, which has already been described in connection with FIGS. 1 b and 1 c. However, this differs from the direction of flow of the exhaust gas flow, which is to be reversed by 180 °, which in the second exemplary embodiment is deflected by the second conduit section 12 ', which is formed here in the outer channel, and in the central region with particle filter 4' arranged therein. This is also well the representation of the corresponding arrows in Figs. 2b and 2c removable. Structurally, the two embodiments of the particulate filter assembly 10, 10 'differ only with respect to the formation of the outlet end, in particular with respect to the rear deflecting element e', wherein the exhaust system thereby changed while the flow of exhaust gases and the inlet end , in particular with respect to the front deflecting element c ', changes in the arrangement, but requires essentially no structural adjustments.

A third exemplary embodiment of a particle filter arrangement 10 "according to the invention will now be explained in more detail with reference to the schematic longitudinal section of Fig. 3. The present third exemplary embodiment of the particle filter arrangement 10" according to the invention is similar in this respect to the first two exemplary embodiments in that three line sections 11 ", 12" and The exhaust gas flow indicated by arrows enters the particulate filter assembly 10 "through the inlet portion a". "A catalyst 6" is provided in the filter stem portion or catalyst portion b " Following this, the exhaust gas flow enters the In the rear deflection section e ", the exhaust gas flow from the first line section 11" is deflected outwards by approximately 180 degrees into the second line section 12 ". In the outer region of the section c "then a new deflection to the outside takes place in about 180 degrees of the exhaust gas flow in the third line section 13" instead. After flowing through the third line section 13 ", the exhaust gases pass into the filter post section f and then into the outlet section g". Characteristic of the present third exemplary embodiment of a particle filter arrangement 10 "according to the invention is that no distribution and deflection element is provided in the section c". This means, in particular, that the exhaust gas flow arrives directly without changing direction from the inlet section a "coming into the filter section d". The two deflections of the exhaust gas flow according to the invention by approximately 180 degrees are provided in the rear deflection section e "and only in the outer region of the section c". Although omitting the distribution and deflection element in the section c ", the filter performance of the particle filter arrangement 10" is reduced because the exhaust gas streams arriving from the engine are no longer heated as described by the heat exchange effect described in connection with the first two exemplary embodiments without mixing of incoming relatively cold exhaust gases with recycled, heated by treatment exhaust gases is the case. However, the present third exemplary embodiment has the advantage of much cheaper production costs. Due to the two-time deflection to the outside (and not even inward as in the first two embodiments), the exhaust gas flow and thus the design is much easier. Furthermore, this embodiment is advantageous in that limits for the back pressure (usually of a few hundred millibars at full load) are avoided. In this variant of the invention, a corresponding predetermined maximum backpressure value, the excess of which can lead to overheating or damage to the engine, can be adjusted in a simple manner by the transverse and longitudinal dimensions of the particulate filter 4 "are easily adapted according to the engine used. The invention has been explained in more detail above with reference to preferred embodiments thereof. However, it will be obvious to those skilled in the art that various modifications and changes can be made without departing from the spirit of the invention.

Claims

claims

1. A particulate filter arrangement (10, 10 ', 10 ") for filtering exhaust gases of an internal combustion engine, in particular a diesel engine, having an inlet and an outlet, wherein at least one particulate filter (4, 4') is arranged in the flow path of the exhaust gases between inlet and outlet wherein the exhaust gases are conducted in a conduit, the conduit having a first section (11; 11 '; 11 ") in which the exhaust gases are directed substantially in the direction of the outlet, the conduit further comprising a second section (12; 12 12), in which the exhaust gases are directed substantially in the direction of inlet, characterized in that the conduit further comprises a third section (13, 13 ', 13' ') in which the exhaust gases are directed substantially in the direction Outlet be led.

Particulate filter arrangement (10, 10 ', 10 ") according to claim 1, characterized in that the exhaust gases separate the first, second and third sections (11, 12, 13; 11', 12 ', 13', 11",

12 ", 13") flow through the line one after the other.

Particulate filter arrangement (10, 10 ', 10 ") according to claim 1 or 2, characterized in that in the first, second or third section (11, 12, 13; 11', 12 ', 13'; 11", 12 " , 13 ") of the line of at least one particulate filter (4, 4 ') is arranged.

Particulate filter arrangement (10; 10 ', 10 ") according to one of claims 1 to 3, characterized in that in the first, second or third section (11, 12, 13; 11', 12 ', 13'; 11" , 12 ", 13") a further particle filter (14) is arranged.

5. Particle filter arrangement (10, 10 ', 10 ") according to claim 3 or 4, characterized in that the at least one particle filter (4, 4') and the further particle filter (14) are integrally formed as a filter monolith.

Particulate filter arrangement (10, 10 ', 10 ") according to one of claims 1 to 5, characterized in that between the first and the second section (11, 12; 11', 12 ';11", 12 ") and the second and third sections (12, 13, 12 ', 13', 12 ", 13"). are provided in the line in which the flow direction of the exhaust gases is substantially reversed.

7. Particle filter arrangement (10, 10 ', 10' ') according to claim 6, characterized in that in at least one of the regions, a catalyst (36, 36') is arranged.

Particulate filter arrangement (10; 10 ', 10 ") according to one of Claims 1 to 7, characterized in that the first, second and third sections of the duct (11, 12, 13; 11', 12 ', 13'; 11" , 12 ", 13") are arranged substantially concentrically with one another.

Particulate filter arrangement (10; 10 ', 10 ") according to one of the preceding claims, characterized in that one of the first, second and third sections (11, 12, 13; 11', 12 ', 13'; 11", 12 " , 13 ") has substantially the shape of a cylinder and the other two sections have substantially the shape of a circular ring cylinder.

A particulate filter assembly (10; 10 '; 10 ") according to any one of the preceding claims, characterized in that the first and second portions (11, 12; 11', 12 '; 11", 12 ") and / or the second and third portions Sections (12, 13, 12 ', 13', 12 ", 13") and / or the first and third sections (11, 13; 11 ', 13', 11 ", 13") of the conduit through a common wall (FIG. 17, 18, 17 ', 18') are separated.

11. Filter assembly (10; 10 ') according to one of the preceding claims, CIa by ₁ in that the particle filter arrangement (10; 10') a distribution and

Deflecting element, which leads a first exhaust gas from the inlet inlet to the first portion (11; 11 ') of the conduit and a second portion of the conduit (12; 12') incoming second exhaust gas flow to the third portion (13; 13 ') of the conduit ,

12. Particle filter arrangement (10, 10 ', 10'') according to claim 11, characterized in that the distribution and deflection element for guiding the first and second exhaust gas has respective channels, wherein at least a part of the outer wall of the channel of the first exhaust gas flow forms the inner wall of the channel of the second exhaust gas flow.

13. Particle filter arrangement (10, 10 ', 10' ') according to one of the preceding claims, characterized in that the particle filter arrangement (10, 10', 10 ") is formed substantially symmetrically to a central axis.

14. A particulate filter arrangement (10, 10 ') according to any one of the preceding claims, characterized in that the particulate filter arrangement (10, 10') has at least the following sections in the direction from the inlet to the outlet: a) a first section (c, c ') ), which has a distribution and deflection element for the exhaust gases; b) a second section (d; d ') having at least one particulate filter; and c) a third section (e, e ') having a deflecting element for the exhaust gases.

Particulate filter arrangement (10; 10 ', 10 ") according to claim 13, characterized in that the first, second and third sections of the duct (11, 12, 13; 11', 12 ', 13') in the second section (b b ') of the particle filter arrangement (10, 10') are arranged.

16. Particle filter arrangement (10, 10 ', 10' ') according to one of the preceding claims, characterized in that the particle filter arrangement (10, 10') in the flow direction of the exhaust gases immediately behind the inlet and / or before the first section of the line arranged catalyst (6, 6 ', 6 ").

17. Particle filter arrangement (10, 10 ', 10'') according to one of the preceding claims, characterized in that the particle filter arrangement (10, 10') has a flow direction of the exhaust gases immediately before the outlet and / or behind the third section (13; ') the line arranged fine dust filter has.

18. Particulate filter arrangement (10, 10 ', 10 ") for filtering exhaust gases of an internal combustion engine, in particular a diesel engine, having an inlet and an outlet, wherein in the flow path of the exhaust gases between the inlet and outlet is provided at least one deflecting element for changing the direction of the exhaust gas flow characterized in that the deflecting element has a catalyst (26; 26 '; 36).

19. Particle filter arrangement (10, 10 ', 10' ') according to claim 18, characterized in that the deflection element is designed as a substantially U-shaped channel for the exhaust gas flow, in which at least partially the catalyst (26, 26') arranged is.

20. Particle filter arrangement (10, 10 ', 10' ') according to claim 18 or 19, characterized in that the catalyst (36) is formed from a wire mesh.

21. A particulate filter arrangement (10, 10 ', 10' ') for filtering exhaust gases of an internal combustion engine, in particular a diesel engine, having an inlet and an outlet, characterized by a distribution and deflection element, which a first exhaust gas flow substantially while maintaining its direction in distributed the arrangement and a second, flowing in substantially opposite direction exhaust gas flow at an angle, preferably in about 180 degrees, deflects, wherein the two exhaust gas streams do not mix.

22. A method for filtering exhaust gases of an internal combustion engine, in particular a diesel engine, by means of a particulate filter assembly (10; 10 ', 10' ') with an inlet and an outlet, characterized in that the flow direction of the exhaust gases between the inlet and outlet at least twice is deflected in about 180 degrees.