EP2478194A1

EP2478194A1 - Exhaust gas treatment device having two honeycomb bodies for generating an electric potential

Info

Publication number: EP2478194A1
Application number: EP10745646A
Authority: EP
Inventors: Jan Hodgson; Christian Vorsmann
Original assignee: Emitec Gesellschaft fuer Emissionstechnologie mbH
Current assignee: Continental Automotive GmbH
Priority date: 2009-09-14
Filing date: 2010-08-26
Publication date: 2012-07-25
Anticipated expiration: 2030-08-26
Also published as: WO2011029728A1; IN2012DN01833A; RU2496012C1; US8628606B2; EP2478194B1; KR101319139B1; JP2013504412A; KR20120053076A; US20120186447A1; JP6045346B2; CN102498269A; CN102498269B; DE102009041092A1

Abstract

The invention relates to an exhaust gas treatment device (11) comprising at least one first at least partially electrically conductive honeycomb body (12) having a first front face (3) and a first rear face (26), a second at least partially electrically conductive honeycomb body (13) having a second front face (25) and a second rear face (27), and intermediate space (15) between the first honeycomb body (12) and the second honeycomb body (13), a voltage supply (18) for implementing an electric potential between the first honeycomb body (12) and the second honeycomb body (13), and a plurality of electrodes (6) that are fastened to the first honeycomb body (12), protrude beyond the first rear face (26) with a first length (8) into the intermediate space (15), and are positioned at a first distance (16) from the second front face (25) of the second honeycomb body (13). The invention further relates to a method for treating motor vehicle exhaust gas comprising particles.

Description

The invention relates to an exhaust gas treatment device for generating an electrical potential or an electric field and / or plasma. With this plasma soot particles are at least agglomerated or electrically charged in an exhaust gas flow, so that a deposition of the particles is promoted in a particulate filter. An exhaust treatment device of this kind can be used, for example, in a motor vehicle.

In motor vehicles with mobile internal combustion engines and especially in motor vehicles with diesel engines are regularly amounts of soot particles contained in the exhaust gas of the internal combustion engine, which must not be discharged into the environment. This is predetermined by corresponding exhaust regulations that specify limit values for the number and mass of soot particles per exhaust gas weight or exhaust gas volume and in some cases also for an entire motor vehicle. Carbon black particles are in particular unburned carbons and hydrocarbons in the exhaust gas.

It is known that the provision of an electric field and / or a plasma causes an agglomeration of small soot particles into larger soot particles and / or an electric charge in soot particles. Electrically charged soot particles and / or larger soot particles are regularly deposited in a filter system clearly easy. Soot particle agglomerates are transported more carrier in an exhaust gas flow due to their greater inertia and thus store easier at deflection of an exhaust gas flow. Electrically charged soot particles are drawn to surfaces due to their charge, to which they attach and release their charge. This also facilitates the removal of soot particles from the exhaust stream in the operation of motor vehicles. The already proposed systems for generating or (temporarily) maintaining an electric field and / or plasma are usually technically very complex and / or inadequate in terms of efficiency. It was also possible to identify problems in the formation of a uniform and / or electric field adjusted specifically for the exhaust gas flow. In any case, no system yet appears ripe for mass production in the automotive industry.

The present invention is now based on the objects at least partially to solve the problems described in the prior art and in particular to disclose a device for generating an electric field for a mobile exhaust treatment system improved compared to the prior art. In addition, a method for treating an exhaust gas is to be specified.

These objects are achieved with a device according to the features of patent claim 1 and a method according to the features of patent claim 8. Further advantageous embodiments of the device and the method are given in the dependent formulated each patent claims. The features listed individually in the claims are combinable with each other in any technologically meaningful manner and can be supplemented by explanatory facts from the description, wherein further embodiments of the invention are shown.

The device according to the invention is an exhaust gas treatment device, comprising at least:

a first at least partially electrically conductive honeycomb body having a first front side and a first rear side, a second at least partially electrically conductive honeycomb body having a second front side and a second rear side, a gap between the first honeycomb body and the second honeycomb body, a power supply for forming an electric potential between the first honeycomb body and the second honeycomb body, and

a plurality of electrodes affixed to the first honeycomb body extend beyond the first backside with a first one

Length extend into the gap and are positioned at a first distance to the second front side of the second honeycomb body. In such exhaust gas treatment apparatus, an electric field can be generated by means of the voltage source between the electrodes (first pole) on the first honeycomb body and the second honeycomb body (second pole). In this case, the electrodes essentially act as punctiform electrodes with respect to a planar electrode that is formed with the second front side of the second honeycomb body. Such an arrangement is particularly suitable for generating an electric field and / or for the formation of a plasma, because electrical charges due to a strong concentration of the electric field in this area regularly emerge at the punctiform electrodes. The multiplicity of electrodes substantially improves the design a specific predetermined field in the space.

The first honeycomb body and / or the second honeycomb body preferably have metallic components that are electrically conductive. In addition to extruded honeycomb bodies, which are at least partially constructed with such materials, find honeycomb body application, which are constructed with at least one at least partially structured metal foil (possibly also from stacks with alternating smooth and corrugated metal foils). The first honeycomb body and / or the second honeycomb body preferably has (rectilinear and / or parallel) channels extending from the front side to the rear side, which possibly are formed by perforated channel walls. The first honeycomb body and / or the second honeycomb body preferably have a channel density of between 50 cpsi and 1000 cpsi, preferably about 600 cpsi [channels per square inch]. This will be enough connection points over the cross section provided for the electrodes, so that the surface or spatial expression of the electric field can be set very accurately. At least a portion of the electrodes, preferably all electrodes, are formed in the manner of (straight-line) metallic pins having a diameter of between 0.5 mm and 3 mm, preferably 1 mm to 2 mm [mm].

A significant component of this exhaust gas treatment device is therefore the first honeycomb body, which is instrumental in providing the entire arrangement for the formation of the electric field. This is thus independently of the overall arrangement described as follows: At least partially electrically conductive honeycomb body having a first front side and a first rear side, wherein a plurality of electrodes, which are attached to the first honeycomb body, beyond the first rear side with a first length extend.

The electrodes are preferably electrically conductively connected to the honeycomb body, for. B. soldered or welded. The number of electrodes is preferably at least 10 or even at least 30.

With regard to the provision of the electrodes, it is preferred if the first length with which the electrodes project beyond the first back side of the first honeycomb body is at least 2 mm [millimeters], preferably at least 3 mm. The first length should also be at most 20 mm, preferably at most 15 mm and particularly preferably at most 10 mm. It is preferred that all the electrodes meet the above requirements, wherein optionally at least for a portion of the electrodes, however, different first lengths may be provided. On the one hand, this characteristic of the first length (or of the supernatant) of the electrodes ensures that the electric field forms only between the electrodes and the second honeycomb body and not between the second honeycomb body and the first honeycomb body. At the same time, sufficient compactness and mechanical stability of the exhaust gas treatment device are ensured. The inventive Permitted exhaust gas treatment device has the advantage that the position of the electrodes can be set very precisely and thus a particularly well-defined electric field or plasma can be operated in the intermediate space. Thus, the first length (or the overhang) of the electrodes can be adapted in a targeted manner as a function of the voltage supply, the exhaust gas flow to be treated and / or the spatial conditions.

As an alternative or cumulative to the attachment of the plurality of electrodes and the first honeycomb body, it is proposed that a plurality of electrodes attached to the second honeycomb body extend beyond the second front side with a second length into the gap and at a second distance are positioned to the first back of the first honeycomb body. The amount of the second length and / or the amount of the second distance may be different from or equal to the amount of the first length and the amount of the first distance, respectively.

Further advantageously, the exhaust gas treatment device is further developed if the first length is at least one electrode different from the first length of the remaining electrodes. In this way, in the region of the at least one longer or shorter electrode, a concentrated or expanded electric field can be generated towards the second front side of the second honeycomb body. This can be useful, for example, in the central region of the honeycomb body, where an increased exhaust gas flow occurs and thus more particles also have to be deposited.

In addition to the first length, the electrodes (alternatively or cumulatively) may differ from one another, at least with regard to one of the following properties:

Material,

Orientation (to the flow direction, to the front and / or back, etc.),

Distance to the adjacent electrode, Connection to the first honeycomb body (contact surface, contact length, connecting means, etc.),

Power supply (voltage sources, electrical connection conductors, etc.),

- Shape (rod, multi-tooth, plate, etc.)

The exhaust gas treatment device is also advantageous if at least the first rear side of the first honeycomb body or at least the second front side of the second honeycomb body has a non-planar shape. By such an arrangement, the flow distribution over the cross section can be influenced by the honeycomb body. For example, the channels of the honeycomb body may be formed by a non-planar shape of a honeycomb body of different lengths. Thus, the structure of the honeycomb body or the prevailing exhaust gas flow can be adapted to the producible electric field.

In addition, it is possible for the first back side of the first honeycomb body and / or the second front side of the second honeycomb body to have a shape deviating from a planar (in other words, flat or in a plane) surface, these differences in shape (or over the cross section different length running gap) are compensated by a variation of the first length of the electrodes. As a result, however, the first distance between the electrodes and the second honeycomb body can nevertheless be set the same at each location, although the first rear side of the first honeycomb body is arranged at different distances from the second front side of the second honeycomb body.

It is further preferred that the at least one electrode has a conically tapered tip. It is further preferred that all electrodes have such a tip. By a tapered tip a greater concentration of the electric field can be achieved in the region of this tip, whereby the formation of an electric field or plasma between the electrodes and the second honeycomb body is further favored. At the same time, the pins that make up the Electrodes are made to have a certain thickness which is greater than the cross section of the tip, whereby a high mechanical stability of the electrodes and a good attachment of the electrodes is achieved in the first honeycomb body.

It is also advantageous if the at least one electrode is offset toward the intermediate space. This means, in particular, that the diameter of the electrode changes abruptly at least once, in particular decreases in the direction of the gap. In this way, a secure attachment to the first honeycomb body is ensured even when the electrode is worn.

Especially with regard to the application in the motor vehicle has been found to be advantageous in that the first distance is between 5 mm and 100 mm. Very particularly preferred is the range of 25 mm to 40 mm. It has been found that such first distances for forming an electric field or plasma are particularly advantageous. Furthermore, it is also proposed that an insulation surrounding the intermediate space be provided. The first honeycomb body is generally to be electrically insulated from the rest of the exhaust system, and in particular also against a surrounding exhaust pipe, so that a voltage (only) between the electrodes and the second honeycomb body can be established. An electrical insulation surrounding the gap is also advantageous in that an electric field is formed only between the electrodes and the second honeycomb body and not between the electrodes and the wall of the exhaust pipe. It is also possible to avoid an electric field between the wall and the electrodes in that the distance from the electrodes to the wall is in each case greater than the distance from the electrodes to the second honeycomb body. Particularly preferred as electrical insulation between the two honeycomb bodies a ring of polymethyl methacrylate or a similar material is provided. According to a development of the exhaust gas treatment device, the second honeycomb body is annular. In particular, the second honeycomb body is arranged annularly around the original central flow direction of the exhaust gas, so that the exhaust gas is at least partially deflected for flowing through the second honeycomb body. The second honeycomb body can therefore also be used in particular as an annular catalyst carrier body

It is also possible to carry out the electrical insulation of at least one honeycomb body made of mica. In particular, mica is a clear transparent material (alumino silicate) with a high dielectric resistance; it is resistant to a constant working temperature of at least 550 C and has a melting point of about 1250 C. In addition, mica is resistant to almost all media such as e.g. Alkalis, chemicals, lanes, oils and acids. The mica insulation can be designed, for example, as a bearing mat, so that at the same time it also compensates for expansion differences due to temperature differences between the first honeycomb body and / or the second honeycomb body and the exhaust gas line. The electrical insulation should have a dielectric strength against electrical voltages of at least 20 kV [kilovolts - 20,000 volts], preferably at least 30 kV [kilovolts - 30,000 volts].

According to a development of the exhaust gas treatment device, the voltage source for generating an electrical voltage of at most between 5 kV [kilovolts - 5,000 volts] and 30 kV [kilovolts - 30,000 volts] is set up between the first honeycomb body and the second honeycomb body. The supply of the electrodes with voltage is carried out regularly (individually, jointly and / or grouped) via the electrically conductive first honeycomb body. Thus, in particular a high-voltage supply is proposed here. At a distance between 5 mm and 50 mm and a voltage of 5 kV [kilovolts], mean field strengths in the space of more than 1 million V / m [volt per meter] can be achieved. In the area of the electrodes, due to the point-shaped form of the electrodes, there is still a concentration of the electrical current Field that goes well beyond this value. Such electric fields are particularly suitable for the formation of a plasma. The high field concentration in the region of the electrodes promotes the escape of electrons from the electrodes.

It is further proposed that a connection of the power supply with at least the first honeycomb body or the second honeycomb body takes place at least in sections via a coaxial cable. A shield of the coaxial cable can thus serve as a positive conductor for connecting the voltage supply to the first honeycomb body or the second honeycomb body and an inner conductor of the coaxial cable as a negative conductor for connecting the voltage source to the second honeycomb body or the first honeycomb body. The degree of protection of the connection should also be independent of the IP68 coaxial cable and should therefore be dustproof and protected against constant submersion.

Furthermore, it is considered advantageous if the first honeycomb body has at least one at least partially structured metal foil and the second honeycomb body has at least one filter material. A partially structured metal foil may also be provided in the second honeycomb body. An at least partially structured metal foil is regularly electrically conductive and can thus ensure the voltage supply of the electrodes. The at least partially structured metal foil may be wound, wound and / or stacked with the honeycomb body. The filter material of the second honeycomb body allows effective deposition of the agglomerated or electrically charged soot particles in the second honeycomb body. As a filter material is preferably a metallic fabric and / or nonwoven into consideration, which is formed with a plurality of (welded or soldered together) wire filaments. The second honeycomb body can then be embodied in particular in the manner of an open particle separator, in which the channels are partially bounded by a metal foil with deflections and openings on the one hand and the filter material on the other hand, the channels having no closure from the second front side to the second rear side. but for several deflections or openings with which the exhaust gas with the particles to the filter material (or in an adjacent channel) are directed. In addition, a method is also proposed for treating soot particles in the exhaust gas with an exhaust gas treatment device according to the invention, wherein at least temporarily an electric field is applied between the first honeycomb body and the second honeycomb body, so that at least a part of the soot particles flowing through the exhaust gas treatment device at least ionizes or agglomerates and deposited on the second honeycomb body.

It is preferred that the exhaust gas first passes through the first honeycomb body and is possibly brought into contact with a first catalyst, then flows through the intermediate space in which the electric field is formed, so that there uses an ionization or agglomeration of the soot particles, and finally hits the second honeycomb body, where preferably the soot particles are deposited. The cleaned exhaust gas then exits the exhaust treatment device after exiting the second rear.

It is further preferred if the power supply is operated so that a current between the first honeycomb body and the second honeycomb body is regulated to 0.005 mA [milliampere] to 0.5 mA, preferably to 0.01 mA to 0.1 mA. A current arises in the operation of the exhaust treatment device by a transfer of charges to the soot particles. The regulation of the current to the proposed value range allows sufficient loading of the soot particles, but also prevents the formation of a spark discharge.

The method according to the invention is furthermore advantageous if the electric field is activated and deactivated at a repetition rate of between 2 and 30,000 Hz [1 / second], preferably between 2 and 2,000 Hz and particularly preferably between 50 and 2,000 Hz. Such a repetition rate allows a particularly effective generation an electric field, so that soot particles are at least ionized or agglomerate.

The method is also advantageous if the repetition rate is regulated as a function of the exhaust gas temperature. If the internal combustion engine already supplies exhaust gas with a temperature which is suitable, for example, for a catalytic conversion, the repetition rate and / or the magnitude of the potential difference can be reduced. It is also preferred if the electric field is activated with a rising ramp. This means, for example, that in particular during operation of the power supply with a repetition rate, the voltage or the current is increased to the operating level in a time of at most half of the reciprocal of the repetition rate. It has been found that in this way a higher end tension can be achieved without causing a spark discharge.

In addition, an alternative embodiment of the method is proposed in which a first part of the electrodes is operated differently from a second part of the electrodes. Thus, the electrodes can be operated, for example, with separate circuits, that is activated or deactivated with other voltages and / or operating times. Thus, the electric field can be regulated as a function of the actual exhaust gas flow on the basis of predetermined, calculated and / or measured parameters.

To prevent the deposition of soot particles, the exhaust gas treatment device according to the invention may also be preceded by an additional honeycomb body, which evened out a laminar flow through a flowing exhaust gas flow, so that no flow vortices occur with dead zones when flowing through the downstream exhaust treatment device according to the invention, which favor a deposition of soot particles. Also according to the invention is a motor vehicle, comprising an internal combustion engine and an exhaust gas treatment device according to the invention for the treatment of exhaust gases of the internal combustion engine.

The advantages and special configurations described for the exhaust gas treatment device according to the invention and the special procedures and advantages explained for the process according to the invention can be transferred to one another in an analogous and technologically sensible manner within the scope of the invention.

The invention and the technical environment will be explained in more detail with reference to FIGS. The figures show particularly preferred embodiments, to which the invention is not limited. In particular, it should be noted that the figures and in particular the illustrated proportions are only schematic. Show it:

1 shows a first embodiment of an exhaust gas treatment device according to the invention,

2 shows a second embodiment of an exhaust gas treatment device according to the invention,

3 shows a further embodiment of a first honeycomb body,

4: an additional embodiment of a first honeycomb body, a plan view of a first honeycomb body, and FIG. 6: a motor vehicle, having an exhaust gas treatment device according to the invention.

In FIGS. 1 and 2, exhaust gas treatment devices 11 according to the invention are respectively shown. The exhaust gas treatment devices 11 have a first honeycomb body 12 and a second honeycomb body 13. The first honeycomb body 12 has channels 5 extending from a first front side 3 to a first rear side 26. Likewise, the second honeycomb body 13 has channels 5 extending from a second front side 25 to a second rear side 27. Pin-shaped electrodes 6 are provided on the first honeycomb body 12 , The electrodes 6 are stuck with a second length 21 in channels 5 of the first honeycomb body 12, which is preferably (but not necessarily) such that the (ends 7 of the) electrodes do not protrude beyond the first front side 3. The second length 21 may be designed differently for at least some of the electrodes 6, so that, for example, different (electrical) contacts are realized. The first honeycomb body 12 is preferably made of smooth and structured metal foils 2. The electrodes 6 may be attached to the metal foils 2 by means of soldering and / or welding. Preferably, the electrodes 6 do not completely close those channels 5 into which they are inserted. The metal foils 2 serve here at least partially as electrical conductors, with which the current (separately or together) is led to the electrodes.

The second honeycomb body 13 is likewise partially constructed with structured metal foils 2 in the embodiment variants from FIGS. 1 and 2, wherein these have deflecting structures 30 here. A preferred embodiment is one in which a plurality of deflection structures 30 are arranged in each channel 5. In addition, the second honeycomb body 13 has filter materials 29, preferably (catalytically coated) metallic nonwovens. Soot particles contained in the exhaust gas flow may be deposited in the filter materials 29. A deposition takes place in particular therefore (even without alternate closures of the channels), because an exhaust gas flow flowing through the second honeycomb body 13 is repeatedly deflected by the deflecting structures 30 in the direction of the filter material 29. The deflection structures 30 close the channels 5 of the second honeycomb body 13 only partially.

Between the first honeycomb body 12 and the second honeycomb body 13 in each case a gap 15 is provided, in which an electric field or plasma can be generated during operation. The first honeycomb 12 and the second honeycomb body 13 are spaced apart from each other (opposite) with a second distance 22 with the first rear side 26 and the second front side 25. The electrodes 6 project from the first honeycomb body 12 with a first length 8, so that a first distance 16 exists between the electrodes 6 and the second front side 25 of the second honeycomb body. The electrodes 6 also have tips 10, which are preferably tapered, to achieve an increased concentration of electric field in operation at the tips 10.

The first honeycomb body 12 and the second honeycomb body 13 are insulated from each other with an electrical insulation 14. In addition, there is a voltage supply 18, by means of which an electrical voltage between the first honeycomb body 12 (or the many electrodes) and the second honeycomb body 13 (or its second front surface) can be generated.

There are various design options, such as the first honeycomb body 12 and the second honeycomb body 13 may be isolated from each other. As shown in FIG. 1, the first honeycomb body 12 and the second honeycomb body 13 may be provided with an insulation 14 which electrically separates the entire exhaust gas treatment device 11. If appropriate, similar insulations are then also formed in front of the first honeycomb body or after the second honeycomb body in order to electrically decouple the rest of the exhaust system if, for B. the first honeycomb body is supplied via the housing with electrical energy.

According to the embodiment in FIG. 2, however, the first honeycomb body 12 can also be separated from the exhaust system with an insulation 14, so that the power supply through the housing or the exhaust gas line 20 takes place by means of an electrically insulated connection. To limit the electric field or the gap 15 may also be provided an insulation 14, for. B. in the manner of a circumferential ring, as indicated in Fig. 2. By such an annular insulation 14 can be prevented that between the exhaust pipe 20 and the electrodes 6, an electric field is generated.

According to the embodiment in FIG. 1, a cover 17 can also be provided for the insulation 14, by means of which a flow of the insulation 14 with exhaust gas or soot particles can be at least partially prevented. Thus it can be prevented that soot particles deposit in the region of the insulation 14 and form a short-circuit path.

During operation of the exhaust gas treatment device 11, electrical insulation 14 can be freed of deposits on a regular basis by applying a short and strong current pulse to the electrical insulation 14, which leads to heating and finally burning off of the soot particles. It can also be triggered several such current pulses. For example, it is possible to trigger such a sequence of current pulses regularly before the beginning or at the start of operation of an exhaust gas treatment device according to the invention. Such a current pulse can be triggered by a short voltage peak which is applied across the insulation 14 or between the first honeycomb body 12 and the second honeycomb body 13. Such a voltage peak can be significantly above the normal operating voltage, for example, well above 30 kV [kilovolts - 30,000 volts] and especially well above 50 kV [kilovolts - 50,000 volts]. At such high voltages, an electrical conductivity of the deposited soot is generated on the electrical insulation, so that forms a current pulse. It is important that the voltage peak or the current pulse are very short in time, so that only deposits of soot particles are burned, but the insulation 14 is not damaged.

FIGS. 3 and 4 show further embodiments or details of first honeycomb bodies 12 of an exhaust gas treatment device. These first honeycomb bodies 12 also have metal foils 2 which define channels 5, which extend from a first front side 3 to a first rear side 26. The honeycomb bodies 12 also each have a peripheral surface 4 which surrounds the first honeycomb body 12 between the first front side 3 and the first rear side 26. The plurality of electrodes 6 are respectively fitted into the channels 5 of the first honeycomb body 12 and protrude with a first length 8 across the first back side 26.

According to the embodiment in FIG. 3, the first length 8 may be different for a part of the electrodes 6 (only three electrodes are shown here for illustration, all of which differ in orientation, shape, length, etc.), but that is not mandatory). In the embodiment according to FIG. 4, the first length 8 of the electrodes 6 is the same. However, according to FIG. 4, the first rear side 26 is concave-shaped. The inner ends 7 of the electrodes 6 here form a concave shape. For example, it is possible for a second honeycomb body, which has a correspondingly convex shape, to be arranged opposite a first honeycomb body 12 according to FIG. 4, so that the intermediate space between the first honeycomb body 12 and the second honeycomb body is bent. It is also possible that the first honeycomb body 12 is convex and the second honeycomb body is correspondingly concave. It is also possible that the second distance between the first honeycomb body 12 and the second honeycomb body varies in the region of the intermediate space and / or the first distance between the electrodes 6 and the second honeycomb body varies. Thus, a desired formation of the electrical field or plasma can be achieved in certain areas of the intermediate space and at the same time a targeted influencing of the flow distribution of the exhaust gas via the honeycomb body.

The electrodes can be designed differently. In Fig. 3, three different embodiments of the ends 7 of the electrodes 6 are shown. The uppermost electrode 6 has a bend or a kink. The middle electrode 6 has a tapered tip 10. Alternatively, it is possible for an electrode 6 to also have a screwdriver-shaped tip ending in the form of a flattened line. The bottom electrode 6 is a straight, flat, or even blunt end 7 executed. In further embodiments, not shown here, the electrodes 6 may also have jagged ends 7 with a plurality of tips or rounded ends 7. The electrodes 6 each have a diameter 9, which may be different in the electrodes.

FIG. 5 shows a plan view of the first rear side 26 of a first honeycomb body 12. In this first honeycomb body 12, electrodes 6 are respectively inserted into individual channels 5. The first honeycomb body 12 is made up of a plurality of stacks, comprising smooth and structured metal foils 2, which are wound such that all metal foils lie with their opposite edges against the housing of the honeycomb body and are soldered or welded there. It is possible that the first honeycomb body 12 has a first radial zone 23 and a second radial zone 24 and the density of the electrodes 6 in the first radial zone 23 differs from the density of the electrodes in the second radial zone 24. It is also possible that, for example, the first length and / or the shape of the ends or tips of the electrodes 6 are designed differently in a first radial zone 23 and a second radial zone 24. In particular, the distances 28 of the electrodes 6 may differ from one another in the first radial zone 23 and in the second radial zone 24. Likewise, different power supplies can be provided for the zones, so that an independent operation of the electrodes in the zones can be performed. By these measures, a variation of the electric field over the cross section of the honeycomb body is possible.

6 schematically shows a motor vehicle 1, comprising an internal combustion engine 19 and an exhaust gas line 20, wherein an exhaust gas treatment device 11 according to the invention is provided on the exhaust gas line 20.

The invention provides an exhaust treatment device which is very compact and therefore suitable for use in the automotive industry. Further, it allows the accurate adjustment of the electric field to a to effect efficient cleaning of the exhaust gases. In particular, the problems mentioned above are hereby overcome.

LIST OF REFERENCE NUMBERS

1 motor vehicle

2 metal foil

3 first front

4 peripheral surface

5 channel

6 electrode

7 end

8 first length

9 diameters

10 tip

11 exhaust treatment device

12 first honeycomb body

13 second honeycomb body

14 insulation

15 gap

16 first distance

17 cover

18 power supply

19 burning skr af tmas chine

20 exhaust pipe

21 second length

22 second distance

23 first radial zone

24 second radial zone

25 second front

26 first back

27 second back

28 distance

29 filter material

30 deflecting structure

Claims

Claims 1. Exhaust gas treatment device (11) having at least a first at least partially electrically conductive honeycomb body (12) with a first front side (3) and a first back side (26), a second at least partially electrically conductive honeycomb body (13) with a second front side (25 ) and a second back (27), a space (15) between the first honeycomb body (12) and the second honeycomb body (13), a voltage supply (18) for forming an electrical potential between the first honeycomb body (12) and the second honeycomb body (13), as well as a plurality of electrodes (6), which are attached to the first honeycomb body (12), extend beyond the first back (26) with a first length (8) into the intermediate space (15) and with a are positioned at the first distance (16) from the second front side (25) of the second honeycomb body (13).

Exhaust gas treatment device (11) according to claim 1, wherein the first length (8) of at least one electrode (6) is designed to be different from the first length (8) of the remaining electrodes (6).

3. Exhaust gas treatment device (11), according to one of the preceding claims, wherein at least the first back (26) of the first honeycomb body (12) or at least the second front side (25) of the second honeycomb body (13) have a non-planar shape.

Exhaust gas treatment device (11) according to one of the preceding claims, wherein the first distance (16) is between 5 mm and 50 mm.

5. Exhaust gas treatment device (11) according to one of the preceding claims, wherein insulation (14) surrounding the intermediate space (15) is provided.

Exhaust gas treatment device (11) according to one of the preceding claims, wherein the voltage supply (18) is set up to generate an electrical voltage of more than 5 kV between the first honeycomb body (12) and the second honeycomb body (13).

Exhaust gas treatment device (11) according to one of the preceding claims, wherein the first honeycomb body (12) has at least one at least partially structured metal foil (2) and the second honeycomb body (13) has at least one filter material (29).

Method for treating exhaust gas containing soot particles with an exhaust gas treatment device (11) according to one of the preceding claims, wherein an electric field is applied at least temporarily between the first honeycomb body (12) and the second honeycomb body (13), so that at least part of the exhaust gas treatment device (11) is at least ionized or agglomerated and deposited on the second honeycomb body (13).

Method according to claim 8, wherein a first part of the electrodes is operated differently from a second part of the electrodes (6).

Motor vehicle (1), comprising an internal combustion engine (19) and an exhaust gas treatment device (11) according to one of claims 1 to 7 for treating exhaust gases from the internal combustion engine (19).