Combustor for exhaust gas aftertreatment system, exhaust gas aftertreatment system for internal combustion engine

Abstract

The invention relates to a burner (5) for an exhaust gas aftertreatment system, comprising a housing (6) forming a combustion chamber (7), the housing (6) has an outlet (8) connected or connectable to an exhaust gas line (2) of the exhaust gas aftertreatment system (1), a fuel supply device (17) for supplying fuel (18) into the combustion chamber (7), a fresh air supply device (21) for supplying fresh air (22) into the combustion chamber (7), and a method for igniting a combustion chamber (7) arranged in the combustion chamber (7) and an ignition element (29) for the fresh air-fuel mixture (27) therein. According to the invention, the housing (6) is designed in such a way that the combustion chamber (7) has a cylindrical main section (9) and a projection (10) which projects radially outward from the main section (9), and the ignition element (29) is arranged in the projection (10).

Description

Technical Field

[0001] The invention relates to a burner for an exhaust gas aftertreatment system, the burner having a housing forming a combustion chamber, wherein the housing has an outlet connected or connectable to an exhaust gas line of the exhaust gas aftertreatment system, a fuel supply device for supplying fuel into the combustion chamber, a fresh air supply device for supplying fresh air into the combustion chamber, and an ignition element for igniting a fresh air-fuel mixture arranged in the combustion chamber.

[0002] Furthermore, the invention relates to an exhaust gas aftertreatment system for an internal combustion engine. Background Art

[0003] In order to achieve current emission limits, it is known to use catalysts in exhaust gas aftertreatment systems of internal combustion engines. Catalysts can convert gaseous pollutants such as NOx, HC and CO into harmless products such as N2, H2O and CO2. In order for these catalytic reactions to proceed quickly enough, the temperature of the catalyst should exceed the so-called light-off temperature, which is usually 300°C to 400°C. In order to quickly achieve this state, especially when the internal combustion engine is cold started, so-called catalyst heating measures inside the engine are usually applied. In this case, the efficiency of the internal combustion engine deteriorates due to the late ignition angle, thereby increasing the exhaust gas temperature and the enthalpy input to the catalyst.

[0004] In addition to these catalyst heating measures inside the engine, external catalyst heating measures are also known. For example, the public document DE19504208A1 discloses an exhaust gas aftertreatment system, in which the exhaust gas pipeline of the exhaust gas aftertreatment system is equipped with a burner. The burner has a housing that forms a combustion chamber. The burner also has a fuel supply device and a fresh air supply device. The fuel supply device is configured to supply fuel to the combustion chamber. The fresh air supply device is configured to supply fresh air to the combustion chamber. During the operation of the burner, fresh air and fuel flow through the combustion chamber as a fresh air-fuel mixture. In addition, there is an ignition element for igniting the fresh air-fuel mixture arranged in the combustion chamber. The outlet of the housing is connected to the exhaust gas pipeline of the exhaust gas aftertreatment system in terms of fluid technology. The fresh air-fuel mixture burned in the combustion chamber is supplied accordingly through the outlet of the exhaust gas pipeline so as to heat the exhaust gas pipeline, especially the catalyst of the exhaust gas pipeline. Summary of the invention

[0005] The burner according to the invention having the features of claim 1 has the following advantages: the burner has particularly favorable ignition characteristics. In particular, the ignition of the fresh air-fuel mixture is achieved more quickly than in previously known burners, so that the catalyst can also be heated more quickly. To this end, it is provided according to the invention that the housing is constructed in such a way that the combustion chamber has a cylindrical main section and a bulge protruding radially outward from the main section, and that the ignition element is arranged in the bulge. If the terms "axial" and "radial" are used within the scope of the present disclosure, these terms refer to the longitudinal center axis of the cylindrical main section, but another (directional) reference is disclosed in the expression. Therefore, according to the invention, the combustion chamber has at least two sections, namely a cylindrical main section and a bulge protruding from the main section. When the burner is in operation, the fresh air-fuel mixture usually flows through the cylindrical main section in a spiral or as a swirl. In this case, at the opening surface of the bulge facing the main section, a pulse exchange occurs between the swirl in the main section and the gas volume of the bulge. As a result, a recirculation flow that rotates in the opposite direction to the swirl is generated in the bulge. Compared with the swirl flow in the main section, the recirculation flow in the ridge has a reduced flow velocity. Due to the lower flow velocity, the convective heat output from the ignition element is reduced compared with the arrangement of the ignition element in the main section. The increased convective heat output from the ignition element is disadvantageous for the ignition characteristics of the burner. The fuel supply device is preferably configured to be used for directly metering the fuel into the combustion chamber. The recirculation flow in the ridge causes the fresh air-fuel mixture to stay longer in the area of ​​the ignition element. The longer residence time in the area of ​​the ignition element causes the fuel to evaporate effectively. Preferably, the ignition element is arranged only in the ridge. The ignition element does not extend into the main section of the combustion chamber and is arranged outside the main section. Particularly preferably, the ignition element is arranged so that the recirculation flow in the ridge is concentric with the ignition element. Therefore, the ignition element is circulated by the recirculation flow.

[0006] According to a preferred embodiment, the housing has a first housing part forming the main section and a second housing part forming the protrusion, wherein the first housing part and the second housing part are manufactured separately from each other, and wherein the second housing part is arranged in a through-hole in the housing wall of the first housing part. This embodiment of the housing is easy to implement in terms of manufacturing technology and is therefore preferred. According to another embodiment, the first housing part and the second housing part are constructed in one piece with each other. If the first housing part and / or the second housing part are mentioned below, these housing parts can be manufactured separately from each other or constructed in one piece with each other.

[0007] According to a preferred embodiment, the first housing part has a circular cross section. Accordingly, the main section also has a circular cross section. In the cross section, the cross-sectional surface is oriented perpendicular to the longitudinal center axis of the cylindrical main section. If the first housing part has a circular cross section, a particularly uniform swirl flow is achieved in the main section during operation of the burner. However, the first housing part can also have a cross section that is different from a circle. For example, according to an alternative embodiment, the first housing part has an elliptical cross section or has a rectangular cross section with a rounded portion.

[0008] Preferably, the second housing part has a cross section with a C-shaped course. The opening of the C-shaped course faces the main section. If the second housing part has a cross section with a C-shaped course, a recirculation flow is particularly reliably formed in the bulge when the burner is in operation. Preferably, the inner surface of the second housing part forming the bulge has a particularly continuously curved course. This is particularly advantageous for forming a uniform recirculation flow. Preferably, the second housing part is designed in the shape of a pot, so that the bulge is designed in the shape of a groove.

[0009] According to a preferred embodiment, it is provided that the bulge extends over a circumferential angle of 10° to 50° in the circumferential direction of the main section. The bulge thus does not extend over the entire circumference of the cylindrical main section, but only partially. If the bulge extends over a circumferential angle of 10° to 50°, a recirculation flow is particularly reliably formed in the bulge during operation of the burner.

[0010] Particularly preferably, the bulge extends over a circumferential angle of 20° to 30°. The circumferential angle over which the bulge extends corresponds to the opening angle of the bulge relative to the longitudinal center axis of the main portion.

[0011] According to a preferred embodiment, the axial extension of the ridge is smaller than the axial extension of the main section. The ridge only partially extends along the main section in the axial direction. This ensures that the formation of a uniform swirl in the main section is hardly affected by the ridge.

[0012] According to a preferred embodiment, the ratio of the volume of the main section to the volume of the raised portion is 200:1 to 50:1. This ratio is particularly advantageous with regard to the ignition characteristics of the burner. Preferably, the ratio of the volume of the main section to the volume of the raised portion is 175:1 to 100:1. Particularly preferably, this ratio is 150:1.

[0013] According to a preferred embodiment, the yaw angle of the ignition element is within an angle range starting from 0° and ending at 45°, wherein the yaw angle describes the rotation of the longitudinal center axis of the ignition element relative to the longitudinal center axis of the main section around a vertical axis, which is oriented perpendicular to the longitudinal center axis of the main section and extends through the longitudinal center axis of the main section and through the ignition element, especially through the center of the ignition element. In the case of such an orientation of the ignition element, when the burner is running, a fresh air-fuel mixture is advantageously supplied to the ignition element. The yaw angle is preferably within an angle range starting from 10° and starting from 30°. As mentioned above, the fresh air-fuel mixture usually flows through the main section as a swirl. If the yaw angle is between 10° and 30°, the flow direction of the fresh air-fuel mixture flowing into the ridge can be realized perpendicular to the longitudinal center axis of the ignition element. This is particularly advantageous because a symmetrical recirculation of the fresh air-fuel mixture around the spark plug can be realized. Particularly preferably, the yaw angle is 20°. Preferably, the second housing part has two side walls oriented parallel to the longitudinal center axis of the ignition element, wherein the ignition element is arranged between the side walls. Since the side walls are oriented parallel to the ignition element, the formation of the recirculation flow by the side walls is particularly advantageously supported. If the roll angle is not equal to 0°, the two side walls will also be oriented correspondingly obliquely. Preferably, in addition to the two side walls, there are two further side walls, which are oriented perpendicularly to the side walls oriented parallel to the longitudinal center axis of the ignition element. In particular, the roll angle is 0°. This can be achieved particularly simply in terms of construction.

[0014] According to a preferred embodiment, the pitch angle of the ignition element is within an angle range starting from 0° and ending at 70°, wherein the pitch angle describes the rotation of the longitudinal center axis of the ignition element relative to the longitudinal center axis of the main section around a transverse axis, which is oriented perpendicularly to the longitudinal center axis of the main section and the vertical axis and extends through the ignition element. In principle, a small pitch angle is advantageous because the installation space of the burner in the radial direction is small. In particular, the pitch angle is 0°. As a result, the smallest possible radial installation space can be achieved. However, the contact between the ignition element and the fresh air-fuel mixture can be optimized by a pitch angle different from 0°. Particularly preferably, the pitch angle is within an angle range starting from 20° and ending at 30° for this purpose.

[0015] Preferably, the ignition element is arranged such that the longitudinal center axis of the ignition element is oriented parallel to the longitudinal center axis of the main section. This results in the following advantage: a combustion chamber or housing with a small radial extension can be realized. Due to the swivel angle of 0°, this embodiment can also be realized in a structurally simple manner.

[0016] According to a preferred embodiment, the housing has a rounded portion at at least one transition portion from the main section to the raised portion. As a result, it is easy for the fresh air-fuel mixture to enter the raised portion. As described above, there are preferably two side walls, which are oriented parallel to the longitudinal center axis of the ignition element. Preferably, a rounded portion is constructed in at least one of these side walls, specifically a rounded portion is constructed at the transition portion from the main section to the raised portion. As described above, in addition, preferably, there are also two other side walls, which are oriented perpendicular to the side walls oriented parallel to the longitudinal center axis of the ignition element. Preferably, a rounded portion is also constructed in at least one of these side walls, specifically a rounded portion is constructed at the transition portion from the main section to the raised portion. According to an alternative embodiment, the housing is constructed without a rounded portion at the transition portion from the main section to the raised portion. The manufacture of the housing is thus simplified.

[0017] According to a preferred embodiment, the ignition element is a glow plug. It has been shown that an ignition element constructed as a glow plug is particularly advantageous with regard to the rapid ignition of the fresh air-fuel mixture. Another major advantage of the ignition element constructed as a glow plug is its moisture stability. Due to the dead volume in passive operation, the burner of the exhaust gas aftertreatment system tends to have condensate that may accumulate in the combustion chamber and the fresh air supply. If the burner is subsequently started, this condensate may also be transported to the ignition element. If the ignition element is constructed as a glow plug, the ignition element will at most only be slightly affected by condensate or moisture. Particularly preferably, the ignition element is a ceramic glow plug. Ceramic glow plugs can reach particularly high temperatures, which is advantageous with regard to the ignition characteristics of the burner. According to an alternative embodiment, it is preferably provided that the ignition element is a spark plug.

[0018] Preferably, the fresh air supply device has a sleeve-shaped fresh air supply chamber, wherein the fresh air supply chamber radially surrounds the first housing part, and wherein the second housing part radially protrudes through the fresh air supply chamber. As a result, the fresh air flows through the housing in the region of the sleeve-shaped fresh air supply chamber, which results in the fresh air being heated by the residual heat of the housing before it is supplied to the combustion chamber. This achieves a particularly stable operation of the burner.

[0019] According to a preferred embodiment, the fuel supply device and the fresh air supply device together form a two-substance nozzle. If fresh air and fuel are supplied to the combustion chamber via the two-substance nozzle, the fuel is broken up into fine droplets by the fresh air, so that the fuel is present in the fresh air-fuel mixture in a finely distributed manner. As a result, the evaporation of the fuel by the ignition element can be accelerated, thereby ultimately also accelerating the ignition of the fuel-air mixture.

[0020] The exhaust gas aftertreatment system for an internal combustion engine according to the invention is characterized by a burner according to the invention having the features of claim 15. This also results in the advantages mentioned above. Further preferred features and feature combinations result from the above description and the claims. Preferably, the exhaust gas aftertreatment system comprises an exhaust gas line with a catalytic converter, wherein the exhaust gas line is fluidically connected to the combustion chamber via an outlet of the burner housing. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] In the following, the present invention is explained in more detail with reference to the accompanying drawings.

[0022] Figure 1 A schematic diagram showing an exhaust gas aftertreatment system;

[0023] Figure 2 showing a cross-sectional view of a burner of an exhaust aftertreatment system;

[0024] Figure 3 Another cross-sectional view of the burner is shown;

[0025] Figure 4 Another cross-sectional view of the burner is shown;

[0026] Figure 5 Another cross-sectional view of the burner is shown;

[0027] Figure 6 showing a cross-sectional view of a burner according to another embodiment; and

[0028] Figure 7 A cross-sectional view of a burner according to another embodiment is shown. DETAILED DESCRIPTION

[0029] Figure 1 An exhaust gas aftertreatment system 1 is shown in a schematic diagram. The exhaust gas aftertreatment system 1 has an exhaust gas line 2 with a catalytic converter 3. The exhaust gas aftertreatment system 1 is assigned to an internal combustion engine 4 of a motor vehicle, which is not shown in detail. The outlet of the internal combustion engine 4 is fluidically connected to the exhaust gas line 2, so that the exhaust gas generated during the operation of the internal combustion engine 4 is supplied to the exhaust gas line 2. The exhaust gas of the internal combustion engine 4 flows through the catalytic converter 3 of the exhaust gas line 2, wherein gaseous pollutants in the exhaust gas, such as NOx, HC or CO, are converted into harmless products by the catalytic converter 3. In this case, the efficiency of the catalytic converter 3 is related to the temperature of the catalytic converter 3. In particular, when the catalytic converter temperature is below the so-called light-off temperature, the above-mentioned pollutants may not be completely converted by the catalytic converter 3. This may occur, for example, during a cold start of the internal combustion engine 4.

[0030] In order to accelerate the heating of the catalytic converter 3, in particular when the internal combustion engine 4 is cold started, the exhaust gas aftertreatment system 1 has a burner 5. Figure 1In the exhaust gas aftertreatment system 1 schematically shown in FIG, there is only one catalytic converter 3, and the burner 5 is connected to the exhaust gas line 2 in terms of fluid technology upstream of the catalytic converter 3. Preferably, the exhaust gas aftertreatment system 1 has two catalytic converters 3 connected in series, wherein the burner 5 is then connected to the exhaust gas line 2 in terms of fluid technology upstream of the catalytic converter 3 or between the catalytic converters 3. Figure 2 , Figure 3 , Figure 4 and Figure 5 The embodiment of the burner 5 is explained in more detail. To this end, Figure 2 A longitudinal section through a burner 5 is shown. Figure 3 The burner 5 is shown along the Figure 2 A cross section of the cross-sectional plane AA is shown in FIG. Figure 4 The burner 5 is shown along the Figure 2 Another cross section of the cross-sectional plane AA is shown in . Figure 5 The burner 5 is shown, that is, along Figure 2 A cross-sectional view of the section plane BB is shown in FIG.

[0031] The burner 5 has a housing 6 forming a combustion chamber 7. An outlet 8 of the housing 6 is fluidically connected to the exhaust gas line 2. Therefore, the fresh air-fuel mixture burned in the combustion chamber 7 is supplied to the exhaust gas line 2 in order to heat the catalytic converter 3. The housing 6 is constructed or shaped in such a way that the combustion chamber 7 has a cylindrical main section 9 and a bulge 10 protruding radially outward from the main section 9 with respect to the longitudinal center axis 14 of the main section 9. The housing 6 has a first housing part 11 forming the main section 9. In the present case, the first housing part 11 has an outlet 8. The first housing part 11 is also cylindrically constructed, wherein the first housing part 11 narrows conically in the region of the outlet 8. The housing 6 also has a second housing part 12 forming the bulge 10. The second housing part 12 is manufactured separately from the first housing part 11 and is arranged in a through-hole 13 of a housing wall 16 of the first housing part 11. In the present case, the second housing part 12 is pot-shaped. The second housing portion 12 is formed by a bottom plate 40 and four side walls 41, 42, 43 and 44. The first side wall 41 is opposite to the second side wall 42. The third side wall 43 is opposite to the fourth side wall 44. Figure 1The side walls 43 and 44 are not visible because they are outside the section plane. As can be seen from these figures, the inner surface 51 of the second housing part 12 forming the ridge 10 has a curved course, so that the side walls 41, 42, 43 and 44 transition continuously into the bottom plate 40. Therefore, there is a rounding at the transition from the side walls 41, 42, 43 and 44 to the bottom plate 40. Alternatively, the transition can also be configured without a rounding. Then, the side walls 41, 42, 43 and 44 suddenly transition into the bottom plate 40. The maximum axial extension of the cylindrical main section 9 is greater than the maximum axial extension of the ridge 10. Therefore, the ridge 10 is limited to an axial section of the main section 9.

[0032] The housing 6 has a plurality of rounded portions which are arranged at the respective transitions from the main section 9 into the raised portion 10. Figure 1 As can be seen from the figure, the side walls 41 and 42 are respectively provided with rounded portions 48 and 49. Figure 2 It can be seen in FIG. 4 that a rounding 50 is also formed in the third side wall 43 . The fourth side wall 44 is in the present case free of rounding, so that here an edge is present at the transition from the main section 9 into the bulge 10 .

[0033] As from Figure 3 and Figure 4 As can be seen in the drawing, the first housing part 11 currently has a circular cross section. Correspondingly, the main section 9 also has a circular cross section. The second housing part 12 has a cross section with a C-shaped run, wherein the opening of the C-shaped run faces the main section 9. The ridge 10 extends along the main section 9 only in sections in the circumferential direction of the main section 9. Currently, the ridge 10 extends along the main section 9 over a circumferential angle of about 25° in the circumferential direction. The ratio of the volume of the main section 9 to the volume of the ridge 10 is preferably 200:1 to 50:1, preferably 175:1 to 100:1, and particularly preferably 150:1. Since only a schematic diagram of the burner 5 is given, this volume ratio is not given exactly in the drawing.

[0034] The burner 5 further comprises a fuel supply device 17, which is currently designed as a fuel injector 17. The fuel supply device 17 is designed for supplying a fuel 18 to the combustion chamber 7. Currently, the fuel supply device 17 is designed for metering the fuel 18 directly into the combustion chamber 7. For this purpose, the fuel supply device 17 has a fuel line 19, which is directly connected to the combustion chamber 7 via a fuel inlet 20. The burner 5 further comprises a fresh air supply device 21, which is designed for supplying a fresh air 22 to the combustion chamber 7. For this purpose, the fresh air supply device 21 has a fresh air line 23, which is connected to the combustion chamber 7 via a fresh air inlet 24. The fuel inlet 20 and the fresh air inlet 24 are axially opposite to the outlet 8. The fresh air line 23 has a sleeve-shaped fresh air supply chamber 25, which radially surrounds the first housing part 11. The second housing part 12 radially protrudes through the fresh air supply chamber 25. In the present case, the fuel supply 17 and the fresh air supply 21 together form a two-substance nozzle 26. If fuel 18 and fresh air 22 are supplied to the combustion chamber 7 via the two-substance nozzle 26, the fuel 18 is broken up into fine droplets by the fresh air 22, thereby obtaining a fresh air-fuel mixture 27 in which the fuel 18 is present in a finely distributed manner.

[0035] The burner 5 also has an ignition unit 28 for igniting a fresh air-fuel mixture 27 arranged in the combustion chamber 7. The ignition unit 28 has an ignition element 29 arranged in the raised portion 10. The ignition element 29 extends into the raised portion 10 through the through-hole of the second housing part 12. The ignition element is oriented parallel to the third side wall 43 and the fourth side wall 44. The ignition element 29 is only arranged in the raised portion 10 of the combustion chamber 7, so that the ignition element 29 does not extend into the cylindrical main section 9. Instead, the free end 46 of the ignition element 29 has a retracted installation state (Einbaustand) relative to the main section 9. Therefore, there is a radial distance 31 between the ignition element 29 and the cylindrical main section 9. At present, the ignition element 29 is a glow plug 29, and is particularly preferably a ceramic glow plug 29. However, the ignition element 29 can also be another type of ignition element 29. According to another embodiment, the ignition element 29 is configured as a spark plug.

[0036] According to Figure 2 In the exemplary embodiment shown in FIG, ignition element 29 is arranged such that a longitudinal center axis 32 of elongated ignition element 29 is oriented obliquely to longitudinal center axis 14 of main section 9 .

[0037] The orientation of the ignition element 29 relative to the longitudinal center axis 14 of the main section 9 is described by the pitch angle α of the ignition element 29 and the roll angle β of the ignition element 29. The roll angle β describes the rotation of the longitudinal center axis 32 of the ignition element 29 relative to the longitudinal center axis 14 of the main section 9 about the vertical axis H, which is oriented perpendicularly to the longitudinal center axis 14 of the main section 9 and extends through the longitudinal center axis 14 of the main section and the ignition element 29. The pitch angle α describes the rotation of the longitudinal center axis 32 of the ignition element 29 relative to the longitudinal center axis 14 of the main section 9 about the transverse axis Q, which is oriented perpendicularly to the longitudinal center axis 14 of the main section 9 and the vertical axis H and extends through the ignition element 29.

[0038] According to Figure 1 In the embodiment shown in , the pitch angle α is about 20°. However, a pitch angle α different from this can also be set. Preferably, the pitch angle α is in an angle range starting from 0° and ending at 70°, particularly preferably in an angle range starting from 20° and ending at 30°.

[0039] The yaw angle β of the ignition element 29 is as follows: Figure 5 . Currently, the roll angle β is about 30°. Preferably, the roll angle β is in an angle range starting from 0° and ending at 45°, particularly preferably in an angle range starting from 10° and ending at 30°. If the roll angle β is not equal to 0°, the third side wall 43 and the fourth side wall 44 are oriented tilted corresponding to the roll angle β.

[0040] Below, refer to Figure 4 The functioning of the burner 5 is explained in more detail. Figure 4 The flow direction of the fresh air-fuel mixture 27 in the combustion chamber 7 is shown. Figure 4 It can be seen that the fresh air-fuel mixture 27 flows through the cylindrical main section 9 of the combustion chamber 7 in the sense of a swirl 33. The swirl 33 is generated by a swirl grid 47 which is arranged in the fresh air line 23 upstream of the fresh air inlet 24. At the opening face 15 of the ridge 10 facing the main section 9, a pulse exchange occurs between the swirl 33 in the main section 9 and the gas volume of the ridge 10. This pulse exchange is facilitated by the rounding 50 in the third side wall 43. Due to the favorable yaw angle β, the flow direction of the fresh air-fuel mixture 27 is perpendicular to the longitudinal center axis 32 of the ignition element 29, as in Figure 5As can be seen in FIG. 1 . By means of the pulse exchange, a recirculation flow 35 is generated in the ridge 10, which rotates counter to the swirl flow 33. The recirculation flow 35 has a reduced flow velocity compared to the swirl flow 33. Due to the lower flow velocity in the ridge 10, the convective heat output from the ignition element 29 is reduced compared to the arrangement of the ignition element 29 in the main section 9. As a result, effective heating of the fresh air-fuel mixture 27 can be achieved with the aid of the ignition element 29. This leads to a rapid evaporation of the fuel 18 of the fresh air-fuel mixture 27 in the region of the ridge 10, which ultimately leads to a rapid ignition of the fresh air-fuel mixture 27 at the same glow plug 29.

[0041] Figure 6 FIG. 5 shows a longitudinal section of a burner 5 according to another embodiment. Figure 6 In the burner 5 shown in FIG. 5 , the pitch angle α is 0°. This has the advantage that the radial extension of the combustion chamber 5 can be reduced.

[0042] Figure 7 FIG. 5 shows a cross-sectional view of a burner 5 according to another embodiment. Figure 7 In the burner 5 shown in FIG. , the yaw angle β is 0°. This embodiment of the burner 5 can be realized particularly easily in terms of construction.

Claims

1. A burner for an exhaust gas aftertreatment system, the burner comprising a housing (6) forming a combustion chamber (7), wherein: The housing (6) has an outlet (8) which is connected or can be connected to an exhaust gas line (2) of the exhaust gas aftertreatment system (1), a fuel supply device (17) for supplying fuel (18) into the combustion chamber (7), a fresh air supply device (21) for supplying fresh air (22) into the combustion chamber (7), and an ignition element (29) for igniting a fresh air-fuel mixture (27) arranged in the combustion chamber (7), characterized in that the housing (6) is constructed so that the combustion chamber (7) has a cylindrical main section (9) and a raised portion (10) protruding radially outward from the main section (9), and the ignition element (29) is arranged in the raised portion (10).

2. The burner according to any one of the preceding claims, characterized in that The housing (6) comprises a first housing part (11) forming the main section (9) and a second housing part (12) forming the raised portion (10), wherein the first housing part and the second housing part (11, 12) are manufactured separately from one another and wherein the second housing part (12) is arranged in a through-hole (13) in a peripheral wall (16) of the first housing part (11).

3. The burner according to any one of the preceding claims, characterized in that The first housing part (11) has a circular cross section.

4. The burner according to any one of the preceding claims, characterized in that The second housing part (12) has a cross section with a C-shaped course.

5. The burner according to any one of the preceding claims, characterized in that The elevation (10) extends in the circumferential direction of the main section (9) over a circumferential angle of 10° to 50°, preferably over a circumferential angle of 20° to 30°.

6. The burner according to any one of the preceding claims, characterized in that The axial extension of the raised portion (10) is smaller than the axial extension of the main section (9).

7. The burner according to any one of the preceding claims, characterized in that The ratio of the volume of the main section (9) to the volume of the elevation (10) is 200:1 to 50:1, preferably 175:1 to 100:1, particularly preferably 150:

1.

8. Burner according to any one of the preceding claims, characterized in that The yaw angle (β) of the ignition element (29) is within an angular range starting from 0° and ending at 45°, particularly preferably within an angular range starting from 10° and ending at 30°, wherein the yaw angle (β) describes the rotation of the longitudinal center axis (32) of the ignition element (29) relative to the longitudinal center axis (14) of the main section (9) about a vertical axis (H), the vertical axis being oriented perpendicular to the longitudinal center axis (14) of the main section (9) and extending through the longitudinal center axis (14) of the main section and through the ignition element (29).

9. The burner according to any one of the preceding claims, characterized in that The pitch angle (α) of the ignition element (29) is within an angular range starting from 0° and ending at 70°, particularly preferably within an angular range starting from 20° and ending at 30°, wherein the pitch angle (α) describes the rotation of the longitudinal center axis (32) of the ignition element (29) relative to the longitudinal center axis (14) of the main section (9) around a transverse axis (Q), which is oriented perpendicularly to the longitudinal center axis (14) of the main section (9) and perpendicularly to the vertical axis (H) and extends through the ignition element (29).

10. The burner according to any one of the preceding claims, characterized in that The ignition element (29) is arranged such that a longitudinal center axis (32) of the ignition element (29) is oriented parallel to a longitudinal center axis (14) of the main section (9).

11. Burner according to any one of the preceding claims, characterized in that The housing (6) has a rounding (48, 49, 50) at at least one transition from the main section (9) to the raised portion (10).

12. Burner according to any one of the preceding claims, characterized in that The ignition element (29) is a glow plug (29), in particular a ceramic glow plug.

13. Burner according to any one of the preceding claims, characterized in that The fresh air supply device (21) has a sleeve-shaped fresh air supply chamber (25), wherein the fresh air supply chamber (25) radially surrounds the first housing part (11), and wherein the second housing part (12) radially protrudes through the fresh air supply chamber (25).

14. Burner according to any one of the preceding claims, characterized in that The fuel supply device (17) and the fresh air supply device (21) together form a two-material nozzle (26).

15. An exhaust gas aftertreatment system for an internal combustion engine, characterized in that: The exhaust gas aftertreatment system comprises a burner (5) according to one of the preceding claims.

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