Particle Filter for an Exhaust System as well as a Procedure for the Manufacture of a Particle Filter

Abstract

A particle filter for an exhaust system, in particular of a motor vehicle, provided with a housing having an exhaust gas inlet and an exhaust gas outlet and a porous filter body being disposed in the housing, the filter body is provided with a cover surface and has a large number of flow channels running parallel in the direction of flow. Accordingly, in the filter body, a sensor well is formed to accommodate a sensor element, where such sensor well penetrates at least one of the flow channels. The disclosure further also concerns a procedure for the manufacture of a particle filter.

Claims

1. A particle filter for an exhaust system, in particular of a motor vehicle comprising: provided with a housing having an exhaust gas inlet and an exhaust gas outlet and a porous filter body being disposed in the housing, wherein the filter body is provided with a cover surface and has a large number of flow channels running parallel in the direction of flow, wherein on the inlet side of the filter body facing the exhaust gas inlet as well as on the outlet side facing the exhaust gas outlet, wherein several of the flow channels are closed by an inserted sealing plug, wherein on the inlet side, those of the flow channels are closed which are not closed on the outlet side and, on of the outlet side, those of the flow channels are closed which are not closed on the inlet side, and wherein, in the filter body, a sensor well passing through the cover surface which penetrates several of the flow channels is formed to accommodate a sensor element, wherein the flow channels penetrated by the sensor well are closed on the outlet side by additional sealing plugs.

2. The particle filter according to claim 1, wherein the flow channels on the inlet side, are closed by a first subset of the sealing plugs, and the flow channels on the outlet side, are closed by means of a second subset of the sealing plugs, wherein the first subset contains a first number of the sealing plugs and the second subset contains a second number of the sealing plugs, wherein the first number and the second number are the same or do not differ by more than 1%, more than 2.5%, more than 5%, more than 7.5%, or more than 10%.

3. The particle filter according to claim 1, wherein the sensor well, in the radial direction with respect to a longitudinal center line of the filter body, penetrates the filter body by at least 10%, at least 20%, at least 25%, at least 30%, at least 40%, or at least 50%.

4. The particle filter according to claim 1, wherein the sensor well, in the axial direction and in the tangential direction with respect to the longitudinal center line, penetrates the filter body by at least 5%, at least 10%, at least 15%, at least 20%, or at least 25%.

5. A procedure for the manufacture of a particle filter for an exhaust system wherein the particle filter has a housing having an exhaust gas inlet and an exhaust gas outlet and a porous filter body being disposed in the housing, wherein the filter body is provided with a cover surface and has a large number of flow channels running parallel in the direction of the flow, wherein on the inlet side of the filter body facing the exhaust gas inlet as well as on the outlet side facing the exhaust gas outlet, several flow channels are closed by an inserted sealing plug, wherein, on the inlet side, those of the flow channels are closed which are not closed on the outlet side and, on the outlet side, those of the flow channels are closed which are not closed on the inlet side and wherein, wherein in the filter body, a sensor well passing through the cover surface is formed to accommodate a sensor element, where such sensor well penetrates several of the flow channels, wherein the flow channels penetrated by the sensor well are closed on the outlet side by additional sealing plugs.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0030] The invention will next be explained below in more detail with reference to the sample embodiments shown in the drawing, although without restricting the invention in any manner.

[0031] FIG. 1 is a schematic representation of a longitudinal section through a particle filter for an exhaust system, and

[0032] FIG. 2 is a schematic representation of a cross-section through the particle filter.

DETAILED DESCRIPTION OF THE DRAWINGS

[0033] FIG. 1 shows a longitudinal section through a particle filter 1 for an exhaust system. The particle filter 1 has a housing 2, which is merely indicated in the drawing. In the housing 2, a filter body 3 is disposed, which is made from a porous material and which is preferably provided with a catalytic coating. The filter body 3 has a cover surface 4, which is for example provided in the form of a coating and/or by means of a respective treatment of the filter body 3. The filter body 3 is preferably disposed in the housing 2 in such a manner that its cover surface 4 is arranged at a distance from the housing 2. Alternatively, however, an embodiment of the particle filter 1 can also be carried out wherein the cover surface 4 of the particle filter 3 lies against an internal circumferential surface of the housing 2, in particular in a continuous manner in the circumferential direction.

[0034] In the filter body 3, a large number of flow channels 5 running parallel in the direction of flow is provided, only some of which are identified in this drawing by way of an example. It can be seen that the filter body 3, with respect to its longitudinal center line 6, has a cylindrical shape, in particular a circular cylindrical shape. However, other shapes of the filter body 3, for example a conical shape, can also be realized. On its front side, the filter body 3 has two areas 7 and 8 which are connected with each other via the cover surface 4. In the case of the cylindrical respectively circular cylindrical shape of the filter body 3, the areas 7 and 8 have the same surface area, or at least a similar surface area. The area 7 is located on an inlet side 9, whereas the area 8 is located on an outlet side 10 of the filter body 3.

[0035] Exhaust gas flows over the particle filter 1, respectively over the filter body 3, in the direction of the arrow 11. Both on the inlet side 9 as well as on the outlet side 10, several flow channels 5 are hermetically closed by means of an inserted sealing plug 12. For the inlet side 9, this means that the exhaust gas can not flow into the respective flow channel 5. However, in case the flow channel 5 is closed off on the outlet side 10, the exhaust gas then can not flow through it out of the filter body 3. Preferably, each and every one of the flow channels 5, in particular each and every one of the flow channels 5 passing completely through the filter body 3 in the axial direction, is closed either on its inlet side 9 or on the outlet side 10 by means of such a sealing plug 12.

[0036] Accordingly, for example, the flow through the filter body 3 occurs as shown by the arrows 13. Arrows 13 show, by way of example, that whereas the exhaust gas flows into one of the non-closed flow channels 5 on the inlet side 9, it can no longer flow out of the same because such a channel is closed on the outlet side 10. Therefore, the exhaust gas must pass through the porous filter 3 to a flow channel 5 which is open on the outlet side 10. This passage or the transfer through the filter body 3 cleans the exhaust gas, in particular by at least partially removing particles from it.

[0037] In the filter body 3, a sensor well 14 is formed, which serves to accommodate a sensor element 15, for example in the form of a lambda sensor. For example, the sensor well 14 is provided in the form of a bore, therefore having a circular cylindrical area, which on its end is terminated by a dome-shaped area, in particular an area in the shape of a partial sphere. The sensor well 14 preferably passes through the cover surface 4 of the filter body 3. Furthermore, the sensor well 14 at least partially penetrates at least one of the flow channels 5.

[0038] This means that, initially, despite the sealing plugs 12, flow is possible between the flow channels 5 which are not closed on the inlet side 9 via the sensor well 14 and the flow channels 5 which are not closed on the outlet side 10. Accordingly, it is possible that exhaust gas, without prior passage through the filter body 3, can flow through the filter body 3 in the longitudinal direction. To prevent this, in addition to the sealing plugs 12, additional sealing plugs 16 are provided. They are preferably disposed on the outlet side of those flow channels 5 penetrated by the sensor well 14 and which would otherwise not be closed on the outlet side, meaning that they would not have any sealing plug 12.

[0039] FIG. 2 shows a schematic representation of the cross-section of the particle filter 1 on the outlet side 10. Here, the outlines of the sensor well 14 are indicated. Once again, it is shown that on the outlet side 10, those flow channels 5 which are at least partially penetrated by the sensor well 14 are closed by means of the additional sealing plugs 16.

[0040] The described embodiment of the particle filter 1 makes it possible to achieve very low emission threshold values, and at the same time to comply with diagnostic requirements, since unfiltered passage of the exhaust gas through the particle filter 1 is prevented by the additional sealing plugs 16. The filter body 3, respectively the flow channels 5, can additionally be provided with a catalytic coating, as a result of which a catalytic converter is integrated in the particle filter 1. This leads to a significant cost reduction.