DE102018208924A1 - Device for exhaust aftertreatment with heat insulation - Google Patents

Abstract

Exhaust after-treatment device (1) comprising a first catalyst device (2) and a subsequent second catalyst device (3), wherein the first and the second catalyst device are arranged spatially adjacent to each other. The first catalyst device (2) comprises a first and a second flow channel (11, 12) and the first catalyst device (2) is adapted to pass exhaust gas in a first flow direction (17) through the first flow channel (11) and then in a second, opposite to the first flow direction extending flow direction (18) through the second flow channel (12) to conduct. The second catalyst device (3) comprises a third flow channel (13), wherein the second flow channel (12) of the first catalyst device (2) spatially and fluidically between the first flow channel (11) of the first catalyst device (2) and the third flow channel (13) the second catalytic converter device (3) is arranged, and the second catalytic converter device (3) is designed to pass exhaust gas after leaving the second flow duct (12) of the first catalytic converter (2) in a third flow direction (19) running counter to the second flow direction to guide the third flow channel (13). At least one means for thermal insulation (10, 20, 30, 40) is arranged spatially between the first catalyst device (2) and the second catalyst device (3).

Description

The present invention relates to an apparatus for exhaust gas aftertreatment, a method for operating an apparatus for exhaust gas aftertreatment and a motor vehicle.

In connection with the aftertreatment of exhaust gas from motor vehicles, it is attempted to arrange appropriate catalysts as space-saving as possible. For this purpose, flow channels with return flow areas are usually provided. Thus, the exhaust gas initially flows in a first flow direction and is then deflected into a second flow direction running in the opposite direction to the first flow direction. In this way, in compact catalyst applications, at least two catalyst devices or substrates are arranged side by side in parallel in a confined space.

In the event that one of the catalyst devices or substrates comprises a diesel particulate filter, regeneration cycles are required at regular intervals. During these regeneration cycles, very high gas temperatures occur and temperatures of the components above 700 ° C are reached. If two catalyst devices or substrates in a common housing arranged very close to each other, occurs during the regeneration cycles an asymmetric heat distribution by heat radiation or heat flow or convection from the first catalyst device to the second catalyst device or vice versa. This temperature distribution can lead to the occurrence of high temperature gradients and thermal stresses in the substrate. Such stresses may limit the applications of the substrate, particularly in the context of diesel particulate filter applications.

Catalyst units with thermal barrier coatings are for example in the documents US 2017/0122180 A1 and US 5,589,144 disclosed. In the document US 7,611,561 B2 an insulating air layer is described around a filter block.

Object of the present invention is to provide an advantageous device for exhaust aftertreatment available, which reduces the difficulties described above in connection with high temperature differences.

This object is achieved by a device for exhaust aftertreatment according to claim 1, a method for operating an apparatus for exhaust aftertreatment according to claim 11 and a motor vehicle according to claim 12. The dependent claims contain further advantageous embodiments of the invention.

The device according to the invention for exhaust aftertreatment comprises a first catalyst device and a second catalyst device which adjoins the first catalyst device in the flow direction of the exhaust gas. The first and the second catalyst device are arranged spatially adjacent to one another, for example arranged next to one another. The first catalyst device comprises a first flow channel and a second flow channel. The first catalyst device is designed to guide exhaust gas through the first flow channel in a first flow direction and then to conduct it through the second flow channel in a second flow direction that runs in opposite directions to the first flow direction. The second catalyst device comprises a third flow channel. The second flow channel of the first catalyst device is arranged spatially and fluidically between the first flow channel of the first catalyst device and the third flow channel of the second catalyst device. The second catalyst device is designed to guide exhaust gas through the second catalyst device after leaving the second flow channel of the first catalyst device in a third flow direction, which runs in the opposite direction to the second flow direction. The third flow direction can, for example, extend parallel to the first flow direction. At least one means for thermal insulation is arranged spatially between the first catalyst device and the second catalyst device. The means for thermal insulation is preferably arranged spatially between the second flow channel and the third flow channel.

The device according to the invention has the advantage that, in particular in the context of regeneration processes occurring high temperatures in the first catalyst device or in the second catalyst device affect the other catalyst device to a reduced extent by heat radiation or heat flow. The unwanted temperature gradients described above are reduced in this way.

In a preferred variant, the first catalyst device and the second catalyst device are arranged within a common housing. The first catalyst means may comprise a central axis and the second catalyst means may comprise a central axis, wherein the central axes may be parallel to each other. In a further variant, the first flow channel of the first catalyst device may comprise a central axis and the second Flow channel may be arranged radially outside of the first flow channel. It can enclose the first flow channel in particular radially.

In the context of the present invention, a flow direction that is opposite to one another means that the corresponding flow channels each have central axes which are at an angle of 135 degrees (135 degrees) to 180 degrees (180 degrees) or 0 degrees (0 degrees) to 45 degrees Include degrees (45 °). In an advantageous variant of the first flow channel comprises a central axis and / or the second flow channel comprises a central axis and / or the third flow channel comprises a central axis. The center axes may each enclose an angle of 0 degrees (0 °) to 45 degrees (45 °).

The first flow direction and the second flow direction and / or the second flow direction and the third flow direction may include an angle of 135 degrees to 225 degrees. The named center axes can each define the flow direction in the respective flow channel. For example, the center axis of the first flow channel may define the first flow direction, the center axis of the second flow channel may define the second flow direction, and the center axis of the third flow channel may define the third flow direction.

The first catalyst device may include an outer wall, the second catalyst device may include an outer wall, and the at least one thermal isolation means may be disposed between the outer wall of the first catalyst device and the outer wall of the second catalyst device. This arrangement has the advantage that the outer walls of the first and second catalyst device need not be completely isolated and thus the costs associated with such a solution can be saved.

The device according to the invention for exhaust aftertreatment may comprise more than two catalyst devices, which in the manner described spatially and fluidically adjoin one another, for example next to each other, may be arranged. At least one of the catalyst devices of the device according to the invention may comprise a diesel particulate filter.

The means for thermal insulation may comprise a mat, in particular be designed as a mat. In this case, the mat may have heat-insulating properties, for example comprise heat-insulating material or consist of heat-insulating material. An example of this is in the 1 and 2 shown.

As suitable materials and applications for the insulation of extremely hot components, for example, E-glass fiber fabrics / mats, silicate fiber fabrics / mats or mineral fiber mats can be used. The insulation efficiency depends on the thickness of the fabric / mats or the number of layers used.

In a further variant, the means for thermal insulation may comprise a coating, in particular be designed as a coating. In this case, a heat-insulating layer may preferably be present on a surface region of the outer wall of the first and / or the second catalyst device. In this case, advantageously, the region of the outer wall is coated, which is adjacent to the outer wall of the respective other catalyst device or adjacent thereto. The advantage of only partially coating the outer surface of one or both of the catalyst devices is that only a small area has to be coated and thus costs for a complete coating can be saved.

In a further variant, the means for thermal insulation may comprise at least one closed cavity. The cavity may, for example, be filled with air or another gas or contain vacuum. Preferably, a closed air layer is present between the first catalyst device and the second catalyst device. The closed cavity can be realized, for example, by creating a volume of air sealed off by metal walls, for example metal plates.

In an advantageous variant, the means for thermal insulation comprises a number of flow channels. For example, air flow channels can be provided between the first catalyst device and the second catalyst device, in particular at least one flow channel having an air inlet and an air outlet, wherein air can flow through the at least one flow channel for cooling. The outer walls of the catalyst devices may form wall regions of the flow channels, in particular of the at least one air flow channel. In this way, a passive cooling is realized. An example of this is in the 7 and 8th shown.

In a further variant, at least one flow channel, for example a number of flow channels, is arranged between the first catalyst device and the second catalyst device, in particular between the outer wall of the first catalyst device and the outer wall of the second catalyst device, wherein the at least one flow channel is designed to a fluid, in particular a cooling fluid, to be flown through. The at least one flow channel may include an inlet and an outlet. Through the flow channel, a cooling fluid, for example a gas, such as in particular air, or a liquid, such as water or oil, are passed. This allows active cooling. An example of this is in the 9 and 10 shown.

In the context of the method according to the invention for operating a device for exhaust aftertreatment, which comprises a number of flow channels as a means for heat insulation, a fluid, preferably a cooling fluid, such as air, water or oil, passed through at least one of the flow channels, for example, pumped , The inventive method has the advantages mentioned in connection with the device according to the invention. In particular, it has the advantage that an active cooling is made possible, which can be flexibly adapted to the particular temperatures occurring. For example, in the case of a regeneration of one of the catalyst devices, cooling fluid can be conducted at a certain flow rate through the at least one flow channel. In this way, efficient cooling is available, which is particularly efficient in that it can be used on demand.

The motor vehicle according to the invention comprises a device according to the invention for exhaust aftertreatment described above. It has the features and benefits already mentioned in this context. The motor vehicle may be a passenger car, a truck or a motorcycle.

• 1 zeigt schematisch eine erfindungsgemäße Vorrichtung zur Abgasnachbehandlung in einer perspektivischen Ansicht.
• 2 zeigt schematisch die in der 1 gezeigte Vorrichtung zur Abgasnachbehandlung in einer perspektivischen und geschnittenen Ansicht.
• 3 zeigt schematisch eine weitere Variante einer erfindungsgemäßen Vorrichtung zur Abgasnachbehandlung in einer perspektivischen Ansicht.
• 4 zeigt schematisch die in der 3 gezeigte Vorrichtung zur Abgasnachbehandlung in einer perspektivischen und geschnittenen Ansicht.
• 5 zeigt schematisch eine weitere Variante einer erfindungsgemäßen Vorrichtung zur Abgasnachbehandlung in einer perspektivischen Ansicht.
• 6 zeigt schematisch die in der 5 gezeigte Vorrichtung zur Abgasnachbehandlung in einer perspektivischen und geschnittenen Ansicht.
• 7 zeigt schematisch eine weitere Variante einer erfindungsgemäßen Vorrichtung zur Abgasnachbehandlung in einer perspektivischen Ansicht.
• 8 zeigt schematisch die in der 7 gezeigte Vorrichtung zur Abgasnachbehandlung in einer perspektivischen und geschnittenen Ansicht.
• 9 zeigt schematisch eine weitere Variante einer erfindungsgemäßen Vorrichtung zur Abgasnachbehandlung in einer perspektivischen Ansicht.
• 10 zeigt schematisch die in der 9 gezeigte Vorrichtung zur Abgasnachbehandlung in einer perspektivischen und geschnittenen Ansicht.
• 11 zeigt schematisch ein erfindungsgemäßes Kraftfahrzeug.

The invention will be explained in more detail below with reference to embodiments with reference to the accompanying figures. Although the invention is further illustrated and described in detail by the preferred embodiments, the invention is not limited by the disclosed examples, and other variations can be derived therefrom by those skilled in the art without departing from the scope of the invention.

• 1 shows schematically a device according to the invention for exhaust aftertreatment in a perspective view.
• 2 schematically shows the in the 1 shown device for exhaust aftertreatment in a perspective and sectional view.
• 3 schematically shows a further variant of a device according to the invention for exhaust aftertreatment in a perspective view.
• 4 schematically shows the in the 3 shown device for exhaust aftertreatment in a perspective and sectional view.
• 5 schematically shows a further variant of a device according to the invention for exhaust aftertreatment in a perspective view.
• 6 schematically shows the in the 5 shown device for exhaust aftertreatment in a perspective and sectional view.
• 7 schematically shows a further variant of a device according to the invention for exhaust aftertreatment in a perspective view.
• 8th schematically shows the in the 7 shown device for exhaust aftertreatment in a perspective and sectional view.
• 9 schematically shows a further variant of a device according to the invention for exhaust aftertreatment in a perspective view.
• 10 schematically shows the in the 9 shown device for exhaust aftertreatment in a perspective and sectional view.
• 11 schematically shows a motor vehicle according to the invention.

The 1 shows an inventive device for exhaust aftertreatment 1 in a perspective view. The 2 schematically shows the in the 1 shown device for exhaust aftertreatment 1 in a perspective and cut view.

The inventive device for exhaust aftertreatment 1 includes a first catalyst device 2 and a second catalyst device 3 , The first catalyst device 2 includes an exhaust inlet 4 and an exhaust outlet 5 , You second catalyst device 3 includes an exhaust inlet 6 , which with the exhaust outlet 5 the first catalyst device is connected, and an exhaust gas outlet 7 , The first catalyst device 2 includes an outer wall 8th , The second catalyst device 3 includes an outer wall 9 , Between the outer wall 8th and the outer wall 9 is in the variant shown a means for heat insulation in the form of a heat-insulating mat 10 arranged.

The first catalyst device 2 includes a first flow channel 11 and a second flow channel 12 , The second catalyst device 3 includes a third flow channel 13 , The second flow channel 12 is downstream of the first flow channel 11 arranged. The third flow channel 13 is downstream of the second flow channel 12 arranged. The second flow channel 12 is spatially between the first flow channel 11 and the third flow channel 13 arranged.

The first flow channel 11 includes a central axis 14 , The second flow channel 12 includes a central axis 15 , The third flow channel 13 includes a central axis 16 , In the variant shown, the central axes 14 . 15 and 16 arranged parallel to each other. The second flow channel 12 is in the variant shown radially outside the first flow channel 11 arranged. The central axes simultaneously determine the flow direction in the respective flow channels.

Exhaust gas flows through the first flow channel 11 in the flow direction 17 , flow direction 17 runs parallel to the central axis 14 , Subsequently, the exhaust gas flows through the second flow channel 12 in the flow direction 18 , The flow direction runs 18 parallel to the central axis 15 and opposite to the flow direction 17 , In other words, in the variant shown, the flow directions close 17 and 18 an angle of 180 °. After leaving the second flow channel 12 the exhaust gas flows through the third flow channel 13 in the flow direction 19 , The flow direction runs 19 parallel to the central axis 16 and opposite to the flow direction 18 , The flow directions 18 and 19 So close in the variant shown an angle of 180 °. Furthermore, in the variant shown, the flow directions run 17 and 19 parallel to each other. Deviating embodiments thereof are also possible. So can the flow directions 17 and 18 and / or the flow directions 18 and 19 each include angles between 135 ° and 180 °.

In the in the 3 and 4 shown variant is on the outer wall 9 the second catalyst device 3 a coating 20 applied from a thermally insulating material. Alternatively, the coating 20 also on the outside wall 8th the first catalyst device 2 or on the outer walls of both catalyst devices 2 and 3 be upset. In the variant shown, the coating is only in the area of the outer wall 9 applied, on which the outer walls 8th and 9 both catalyst devices 2 and 3 abut each other.

In the in the 5 and 6 variant shown between the outer wall of the first catalyst device and the outer wall of the second catalyst device is a closed cavity 30 available. This cavity 30 is filled with air, for example. Alternatively, it may be filled with a gas, for example air, at a pressure below atmospheric pressure or with a vacuum. In this way, an efficient cooling layer between the catalyst devices 2 and 3 achieved. The outer walls 8th and 9 can also partially the walls of the cavity 30 form.

In the in the 7 and 8th shown variant is between the outer wall 8th the first catalyst device 2 and the outer wall 9 the second catalyst device 3 a flow channel 40 in the form of a cavity with a number of openings 41 intended. Through the openings 41 can air from the outside through the cavity 40 flow through and so cooling the outer walls 8th and 9 cause.

In the in the 9 and 10 shown variant is between the outer walls 8th and 9 the catalyst devices 2 and 3 at least one flow channel 40 intended. The flow channel 40 includes an inlet 43 and an outlet 44 , Through the inlet 43 For example, a cooling fluid, for example a gas or a liquid, in particular air, water or oil, can flow through the flow channel 40 to the outlet 44 be directed. In this way, an active cooling of the outer surfaces 8th and 9 allows.

The 11 schematically shows a motor vehicle according to the invention 45 , It comprises a previously described device according to the invention for exhaust aftertreatment 1 ,

LIST OF REFERENCE NUMBERS

1

Device for exhaust aftertreatment

2

first catalyst device

3

second catalyst device

4

exhaust inlet

5

exhaust outlet

6

exhaust inlet

7

exhaust outlet

8th

outer wall

9

outer wall

10

heat insulating mat

11

first flow channel

12

second flow channel

13

third flow channel

14

central axis

15

central axis

16

central axis

17

flow direction

18

flow direction

19

flow direction

20

coating

30

closed cavity

40

flow channel

41

opening

42

flow direction

43

inlet

44

outlet

45

motor vehicle

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• US 2017/0122180 A1 [0004]
• US 5589144 [0004]
• US 7611561 B2 [0004]

Claims (12)

A device for exhaust gas aftertreatment (1), which comprises a first catalyst device (2) and a second catalyst device (3) adjoining the first catalyst device (2) in the flow direction (17, 18) of the exhaust gas, wherein the first and the second catalyst device are spatially adjacent to one another are arranged adjacent, the first catalyst device (2) comprises a first flow channel (11) and a second flow channel (12) and the first catalyst device (2) is adapted exhaust gas in a first flow direction (17) through the first flow channel (11). The second catalyst device (3) comprises a third flow channel (13), wherein the second flow channel (12) of the first Catalyst device (2) spatially and fluidically between the first St and the second catalyst device (3) is adapted to exhaust gas after leaving the second flow channel (12) of the first catalytic converter device (11) of the first catalyst device (2) and the third flow channel (13) of the second catalyst device (3) (2) in a direction opposite to the second flow direction, to flow third flow direction (19) through the third flow channel (13), characterized in that at least one means for thermal insulation (10, 20, 30, 40) spatially between the first catalyst device ( 2) and the second catalyst device (3) is arranged. Device (1) according to Claim 1 , characterized in that the means for thermal insulation (10, 20, 30, 40) is arranged spatially between the second flow channel (12) and the third flow channel (13). Device (1) according to Claim 1 or Claim 2 characterized in that the first catalyst means (2) and the second catalyst means (3) each comprise an outer wall (8, 9) and the thermal insulation means (10, 20, 30, 40) between the outer wall (8) of the first catalyst means (2) and the outer wall (9) of the second catalyst device (3) is arranged. Device (1) according to one of Claims 1 to 3 , characterized in that the first flow channel (11) comprises a central axis (14) and / or the second flow channel (12) comprises a central axis (15) and / or the third flow channel (13) comprises a central axis (16) and the central axes each include an angle of 0 degrees to 45 degrees. Device (1) according to one of Claims 1 to 4 , characterized in that the first flow direction (17) and the second flow direction (18) and / or the second flow direction (18) and the third flow direction (19) form an angle of 135 degrees to 225 degrees. Device (1) according to one of Claims 1 to 5 , characterized in that at least one of the catalyst devices (2, 3) comprises a diesel particulate filter. Device (1) according to one of Claims 1 to 6 , characterized in that the means for thermal insulation comprises a mat (10). Device (1) according to one of Claims 1 to 7 , characterized in that the means for thermal insulation comprises a coating (20). Device (1) according to one of Claims 1 to 8th , characterized in that the means for thermal insulation comprises at least one sealed cavity (30). Device (1) according to one of Claims 1 to 9 , characterized in that the means for thermal insulation comprises a number of flow channels (40). Method for operating an apparatus for exhaust aftertreatment (1) according to Claim 10 , characterized in that a fluid is passed through at least one of the flow channels (40). Motor vehicle (45), which is a device for exhaust aftertreatment (1) according to one of Claims 1 to 10 includes.

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