Exhaust burner for an exhaust system of a motor vehicle, and method for assembling an exhaust burner with an integrated cooling circuit

Abstract

The invention relates to an exhaust gas burner (1) for an exhaust system (2) of a motor vehicle (3), the exhaust gas burner having at least the following components: a combustion chamber (5) enclosed by an outer wall (4), the combustion chamber for a channel section (6) in the exhaust system (2); a metering unit (7) for the controlled addition of fuel into the combustion chamber (5); and an ignition unit (8) for igniting a combustible mixture in the combustion chamber (5). The exhaust gas burner (1) is characterized in particular in that a cooling circuit (9) is also arranged in the outer wall (4) of the exhaust gas burner (1), the cooling circuit being used for heat exchange with the metering unit (7) and with the ignition unit (8). With the exhaust gas burner proposed here, good cooling and cost-effective production and simple assembly are achieved.

Description

Technical Field

[0001] The invention relates to an exhaust gas burner for an exhaust system of a motor vehicle and to a method for assembling an exhaust gas burner with an integrated cooling circuit. Background Art

[0002] Exhaust burners for exhaust systems of motor vehicles are known in the prior art, for example for increasing the temperature in the exhaust system, wherein the exhaust gas should preferably be catalytically treated by means of a catalyst unit connected after (downstream) the exhaust burner, and for this purpose a minimum operating temperature should be generated. This is necessary, for example, in combustion engines that produce exhaust gas at (cold) start, so that the desired exhaust treatment can be started as early as possible to avoid harmful substances (such as nitrogen oxides and / or carbon monoxide). It is known that for this purpose, fuel (such as the power fuel of the connected combustion engine) is injected into the combustion chamber of the exhaust burner by means of a metering unit and ignited by means of an ignition unit in the combustion chamber. These components are arranged in the combustion chamber in the exhaust gas flow or close to the exhaust gas flow and are exposed to high exhaust gas temperatures for a long time. In many applications, the exhaust gas burner is as close as possible to the outlet of the combustion engine, for example directly connected to at least one exhaust manifold, and is therefore exposed to particularly high temperatures. It is therefore necessary to design these components to be robust against high exhaust gas temperatures. Nevertheless, the costs for cooling or assembling the corresponding equipment should be low.

[0003] Starting from this, the object on which the present invention is based is to at least partially overcome the disadvantages known from the prior art. The features according to the invention are derived from the independent claims, and their advantageous embodiments are shown in the dependent claims. The features of the claims can be combined in any technically reasonable manner, wherein for this purpose, the explanations from the following description and the features from the drawings can also be used, which include supplementary embodiments of the invention. Summary of the invention

[0004] The invention relates to an exhaust gas burner for an exhaust system of a motor vehicle, the exhaust gas burner having at least the following components:

[0005] - a combustion chamber enclosed by an outer wall, which is used as a channel section in an exhaust system;

[0006] - a metering unit for the controlled addition of fuel into the combustion chamber; and

[0007] - an ignition unit for igniting the combustible mixture in the combustion chamber.

[0008] The exhaust gas burner is characterized in particular in that a cooling circuit is also arranged in the outer wall of the exhaust gas burner, which serves for heat exchange with the metering unit and with the ignition unit.

[0009] Unless expressly stated to the contrary, ordinal numbers used in the preceding and following descriptions are for clarity of distinction only and do not reflect any order or ranking of the components referred to. An ordinal number greater than one does not necessarily mean that another such component must be present.

[0010] For the above-mentioned purposes, the exhaust burner is, for example, particularly adapted for an arrangement directly connected to at least one exhaust manifold of a connected combustion engine and can be incorporated as a channel section in the exhaust system of a motor vehicle for this purpose. In one embodiment, the exhaust burner can be subsequently assembled in the exhaust system. In one embodiment, the exhaust burner is integrated as a channel section in a structurally integrated exhaust system, which exhaust system, for example, comprises at least one exhaust manifold and / or at least one further exhaust treatment unit. In one embodiment, the combustion chamber is surrounded by an inner wall and is formed within the outer wall of the exhaust burner, wherein the inner wall is preferably spaced apart from the outer wall. At least one catalyst unit for treating the exhaust gas flowing through the exhaust system is preferably connected after the combustion chamber, i.e. arranged downstream.

[0011] The metering unit is adapted to be used for inputting fuel, for example the corresponding power fuel of a corresponding combustion engine. In a preferred embodiment, the metering unit is an injection valve, particularly preferably for directly injecting the power fuel directly into the combustion chamber of the combustion engine, for example, being implemented with a so-called solenoid solenoid valve or a piezoelectric actuator.

[0012] The ignition unit is adapted to start the combustion of the mixture in the combustion chamber. The mixture is formed from a fuel introduced by means of a metering unit (or another source) and a gas containing oxygen, such as air from the surrounding environment (process air). The ignition unit is preferably a spark plug (such as used in gasoline combustion engines) and / or is preferably provided by the same voltage source, such as at least one spark plug of the connected combustion engine.

[0013] The cooling circuit proposed here is arranged in as close a contact as possible with the material of the exhaust-side opening or ignition device (e.g. electrode pair or laser diode) surrounding the metering unit, so that a heat exchange that is as direct as possible can be achieved. A coolant is guided in a closed manner in the cooling circuit, wherein the coolant is preferably provided by means of an external coolant source (preferably externally controlled). The coolant is preferably water and particularly preferably a coolant source that is the same as the coolant source used to cool the connected combustion engine. Due to the provision of the cooling circuit, the exhaust burner and therefore the catalytic converter unit connected thereto can be arranged in the exhaust gas flow particularly close to the combustion engine.

[0014] It is proposed that the cooling circuit is arranged completely (i.e. together with the direct components and connecting lines in the ignition unit and the metering unit) in the outer wall of the exhaust gas burner and is adapted to be used jointly for the metering unit and the ignition unit. In this way, the existing installation space in the outer wall of the exhaust gas burner is utilized in many applications. At the same time, the cooling circuit is protected from damage by means of the outer wall.

[0015] Furthermore, the process air required for operating the exhaust gas burner flows through the cooling lines inside the burner. As a result, the coolant releases heat to the process air for the combustion chamber, whereby the process air heats up. After the heated process air enters the combustion chamber of the exhaust gas burner, the process air enables better and faster homogenization of the mixture (evaporation of the fuel) in the area of ​​mixture formation (contact area of ​​the metered fuel and process air).

[0016] In an advantageous embodiment of the exhaust gas burner, it is further provided that the ignition unit and the metering unit are arranged in series connection with one another in the cooling circuit, wherein the ignition unit is preferably connected upstream of the metering unit in the flow direction.

[0017] It is proposed that the cooling devices for the ignition unit and the metering unit are connected in series with each other in the cooling circuit. Alternatively, the ignition unit and the metering unit are formed in parallel with each other in the cooling circuit, for example, they are formed independently of each other with their own external interface to the coolant source, or they are formed by means of the same external interface and are formed to divide the coolant line into two lines in the flow direction internally, wherein the two lines have the same line cross section in one embodiment and different line cross sections in another embodiment.

[0018] Typically, the metering unit is spaced further from the center of the combustion triggered by the ignition unit and / or is cooled by means of evaporative cooling of the fuel when (preferably atomized) entering the combustion chamber. The metering unit is also preferably designed for a smaller maximum thermal load than the ignition unit. It is then advantageous to firstly bring the metering unit into heat exchange with the (new, i.e. cooler) coolant and then bring the ignition unit into heat exchange with the (already heated) coolant. In both cases, it is then sufficient for the temperature difference to be greater and for the cooling power to be achieved with simple means. At the same time, the design with a series-connected cooling circuit is simpler than a parallel connection or separate cooling.

[0019] In an advantageous embodiment of the exhaust gas burner, it is further provided that the cooling circuit comprises a ventilation device.

[0020] In this embodiment, it is proposed that the cooling circuit is adapted to be automatically ventilated, i.e., the entrained gases are conveyed out in its (multiple) cooling lines. Automatic ventilation is carried out independently of the installation position of the exhaust gas burner. As a result, the cooling power is always (constantly) high. In one embodiment, the ventilation device is adapted to be passive, wherein the outflow of gas is possible and is increased, while the outflow of liquid is completely prohibited. Such a ventilation device is adapted so that any entrained gases that may be present are carried and conveyed out by the coolant flow. The cooling circuit is implemented to be completely sealed, i.e. fluid-tight, relative to the interior space of the exhaust gas burner. Automatic ventilation allows reliable and cost-effective ventilation during assembly work and / or maintenance work.

[0021] In an advantageous embodiment of the exhaust gas burner, it is further provided that the cooling circuit has exactly two external connections to which an external coolant source can be connected outside the combustion chamber.

[0022] In this embodiment, the number of interfaces is small and the costs for connecting the cooling circuit to an external coolant source are therefore small. Preferably, the two components for heat exchange are connected in series with each other at the same time with the ignition unit and the metering unit. In a preferred embodiment, one external interface always forms an inlet for the coolant supplied from the outside, and the other external interface always forms an outlet for returning the coolant to the external coolant source. The coolant source is, for example, a tank for coolant, in which the coolant is provided by means of a pump at a predetermined or controlled pressure.

[0023] In an advantageous embodiment of the exhaust gas burner, it is further provided that the cooling circuit comprises at least one section which comprises half shells and / or closed-chamber line elements which are preferably connected to one another in a materially bonded manner, particularly preferably by means of brazing.

[0024] The cooling circuits each include a (metering unit) component for heat exchange with the metering unit and a (ignition unit) component for heat exchange with the ignition unit. In addition, the supply of the components is adapted by means of a coolant source. At least in the case where the components are interconnected in series, the components are connected to each other. These components of the cooling circuit are at least partially described by cooling lines. In one embodiment, at least one component is implemented as a cooling shroud. The cooling shroud has, for example, a channel wall on the cooling side, which is adapted, for example, to be thin-walled, to have a corresponding (close) form, to accommodate a corresponding contour next to it, a thermally conductive paste or other.

[0025] In one embodiment, the cooling line only comprises a connecting line inside the burner without the at least one cooling shroud. The cooling line (preferably also comprising at least one cooling shroud) is provided here as a half shell and / or a closed-chamber pipeline element according to the proposal. The closed-chamber pipeline element is, for example, a tube. The closed-chamber pipeline element has a cross section or a series of such cross sections that are closed around, and these cross sections form (easy to) fluid-tight pipelines as extruded shapes. The closed-chamber pipeline elements can each be connected to other components of the cooling circuit at the end side and are preferably not optimized for heat exchange. The mentioned half shells can preferably be joined to each other to form a closed-chamber pipeline body only when installed in the exhaust gas burner, thereby forming a fluid-tight cooling line or a generally fluid-tight cooling circuit. It should be pointed out here that the cooling circuit does not necessarily have to be divided into independent modules. Preferably, for example, a first half shell is formed, which includes all or at least one of these components and at least partially includes the cooling line; and a second half shell, which includes all or at least one of these components separately and at least partially includes the cooling line. For example, a completely one-piece (first) half-shell can be mounted, for example elastically or plastically, in a portion of the outer wall of the exhaust gas burner, and a (preferably subsequently also completely one-piece) second half-shell can then be joined to the first half-shell in the exhaust gas burner. In a preferred embodiment, one half-shell is designed in one piece with a plurality of components or all components of the cooling circuit, and the other half-shell consists of separate components of the cooling circuit, wherein preferably the one-piece half-shell is the half-shell that is first to be mounted in the exhaust gas burner.

[0026] In a preferred embodiment, the half shells are connected to one another in a materially fitting manner. For example, the half shells are connected to one another by means of laser welding, particularly preferably by means of brazing, wherein a material strength or a reliable tightness of the joint is achieved which is sufficient for the temperatures prevailing in this channel section of the exhaust system. At the same time, if a leak is detected during a tightness test, the joint formed by means of brazing can be easily post-processed.

[0027] In an advantageous embodiment of the exhaust gas burner, it is further provided that the cooling circuit is of modular design and comprises (preferably only) the following modules:

[0028] i. An ignition unit assembly, the ignition unit assembly having a first cooling cover for the ignition unit;

[0029] ii. a metering unit assembly having a second cooling shroud for the metering unit and preferably a holder for the metering unit; and

[0030] iii. a connecting line inside the burner that connects the ignition unit assembly and the metering unit assembly in a flow sense,

[0031] Preferably, the connecting pipeline structure inside the burner is integrally included in the ignition unit assembly.

[0032] Here, a modular structure of the cooling circuit is proposed, wherein each module can be produced and / or provided independently. These modules can be connected to each other before being installed in the exhaust gas burner, or can be connected to each other only when installed in the exhaust gas burner.

[0033] The ignition unit assembly is adapted to exchange heat with the ignition unit and forms a corresponding (first) cooling jacket for this purpose. The first cooling jacket is preferably formed in a corresponding, as surrounding as possible and / or close manner relative to the ignition unit.

[0034] The metering unit assembly is adapted for heat exchange with the metering unit and forms a corresponding (second) cooling shroud for this purpose. The second cooling shroud is preferably formed in a corresponding, as far as possible surrounding and / or close manner relative to the metering unit. In a preferred embodiment, the second cooling shroud simultaneously forms a holder for the metering unit, i.e., the assembled metering unit is fixed in the exhaust gas burner by means of the holder.

[0035] Another module or modules are at least one burner-internal connecting line of the metering unit assembly and the ignition unit assembly, wherein preferably, in addition, a burner-internal connecting line leading to an external interface is formed (possibly formed as a separate module). In a preferred embodiment, the ignition unit assembly and the burner-internal connecting line (towards the metering unit assembly) are formed in an integral structure, i.e., they are joined to one another or formed in one piece before being installed in the exhaust gas burner. In a preferred embodiment, each of these modules or at least one module (preferably a module that is joined to another module only when installed in the exhaust gas burner) is provided as two half shells that are still to be connected to one another.

[0036] According to another aspect, a method for assembling an exhaust gas burner with an integrated cooling circuit according to the above-described embodiment is provided, wherein the assembly method comprises at least the following steps:

[0037] a. placing the ignition unit assembly, preferably together with the connecting lines integrally formed inside the burner, onto the ignition unit and / or onto the ignition unit receiving portion in the inner wall of the combustion chamber;

[0038] b. Orienting the internal interface of the ignition unit assembly placed in step a for the connecting lines inside the burner, and bringing the connecting lines connected to the ignition unit assembly to a position where they are exposed inside the exhaust burner in the final state;

[0039] c. placing the metering unit assembly onto the metering unit and / or onto the metering unit receiving portion in the outer wall of the exhaust burner;

[0040] d. by means of fluid-tightly connecting the connecting line and the metering unit assembly to form the cooling circuit inside the burner; and

[0041] e. After step d, close the exhaust burner.

[0042] The assembly method proposed here can be used to assemble an exhaust gas burner as a preassembled structural unit to be integrated into an exhaust system or can be used to assemble an exhaust gas burner (not preassembled or only partially preassembled) in a corresponding exhaust system. First, an outer wall (preferably provided as a half shell) is provided, wherein a receptacle or channel for a metering unit and an ignition unit is already provided by this outer wall of the exhaust gas burner. Prior to step a, the ignition unit has already been assembled in the outer wall and / or a (separate) ignition unit receptacle is provided in the outer wall. In step a, the ignition unit assembly is directly assembled on the (already assembled) ignition unit or on an ignition unit receptacle (for example, without an assembled ignition unit). In one embodiment, the ignition unit assembly forms an ignition unit receptacle for the ignition unit, wherein preferably, the ignition unit receptacle is subsequently adapted to directly accommodate the ignition unit assembly.

[0043] In step b, the internal interface is oriented to the connecting pipeline inside the burner, wherein in one embodiment, step b is implemented simultaneously with placing the ignition unit assembly in step a. Then, the connecting pipeline inside the burner is connected to the ignition unit assembly (for example, in a fluid-tight manner). In one embodiment, when implementing step a, the connecting pipeline inside the burner is already connected to the ignition unit assembly. In both cases, the connecting pipeline inside the burner is then oriented (preferably before the fluid-tight connection is made) so that the connecting pipeline inside the burner or its end for connecting (preferably directly) to the metering unit assembly is exposed, that is, it is easily accessible in the provided part of the outer wall of the exhaust burner. Therefore, further assembly can be easily performed, but there is also subsequent repair or maintenance. For example, the exposed position is a position in which the internal interface is arranged adjacent to the external interface and / or, for example, on an assembly plane. The external interface is preferably arranged between two half shells of the outer wall of the exhaust burner. In an alternative embodiment, at least one of these external interfaces is integrated into the metering unit assembly.

[0044] In step c, the metering unit assembly is mounted directly onto the (already mounted) metering unit or onto the metering unit receptacle (e.g., without an already mounted metering unit). In one embodiment, the metering unit assembly forms a metering unit receptacle for the metering unit, wherein preferably the metering unit receptacle is subsequently adapted to directly accommodate the metering unit assembly. It should be noted that the sequence is preferably as shown, but it is also possible that step c can be performed before step a, and step a or step c can be performed simultaneously with step b, and steps a to c can be performed simultaneously.

[0045] Finally, in step c, the internal cooling circuit of the burner is formed by connecting the components (and possibly the internal connecting lines of the burner) to one another in a fluid-tight manner. In an alternative embodiment, step d is already carried out before steps a to c (which are to be carried out together later). This means that these components of the cooling circuit are then already connected to one another in advance.

[0046] In the last step e, the exhaust gas burner is then closed, for example by closing the second half shell with the first half shell that was provided before step a (in a gas-tight manner). In one embodiment, preferably after the completion of steps a to d, a separately formed combustion chamber of the exhaust gas burner, which is enclosed by an inner wall, is used, wherein the combustion chamber is preferably connected indirectly or directly to the outer wall in a form-fitting manner and / or by means of a material-fitting connection, particularly preferably by means of brazing. If the exhaust gas burner has not yet been integrated into the exhaust system as a duct segment, a preassembled exhaust gas burner is now provided, which can now be installed in the exhaust system.

[0047] In an advantageous embodiment of the assembly method, provision is also made that, in an intermediate step d1 after step d and preferably before step e, the tightness of the formed cooling circuit is checked.

[0048] By means of the tightness check it is ensured that the heat exchange can function as desired. Preferably, this check is carried out before the exhaust gas burner is closed, so that repair costs are lower. In one embodiment, tightness is reliably ensured in that the tightness only has to be checked during sampling and after the exhaust gas burner has been closed.

[0049] In an advantageous embodiment of the assembly method, it is further provided that the modules are connected by means of welding and / or soldering.

[0050] It is proposed that the components of the cooling circuit are at least partially (preferably as described above at least partially provided as half shells) connected to one another in a materially bonded manner, for example by means of (laser) welding. Preferably, the components are connected to one another by means of brazing, wherein a material strength or a reliable tightness of the joint is achieved which is sufficient for the temperatures prevailing in this channel section of the exhaust system. At the same time, the joint formed by means of brazing can be easily post-processed if a leak is detected during a tightness test. BRIEF DESCRIPTION OF THE DRAWINGS

[0051] The invention is described in detail below in conjunction with the relevant technical background with reference to the accompanying drawings showing preferred designs. The invention is not limited in any way by the purely schematic drawings, wherein it should be noted that these drawings are not accurate in size and are not suitable for defining dimensional ratios. In the drawings:

[0052] Figure 1 : An exhaust burner is shown in side view;

[0053] Figure 2 :The rear view of the connection side shows the Figure 1 Exhaust burner;

[0054] Figure 3 :The top view shows the Figure 1 and Figure 2 Exhaust burner;

[0055] Figure 4 : shows a motor vehicle having an exhaust burner; and

[0056] Figure 5 : A flow chart showing a method for assembling an exhaust gas burner with an integrated cooling circuit. DETAILED DESCRIPTION

[0057] exist Figure 1 , an exhaust gas burner 1 is shown in a side view. The exhaust gas burner 1 shown here (having an outer wall 4, a channel section 6 of the exhaust system 2 and a combustion chamber 5 surrounded by an inner wall 21) has an ignition unit 8, a metering unit 7 and a cooling circuit 9. The metering unit 7 is adapted to be used for feeding fuel into the combustion chamber 5, wherein the fuel is, for example, the corresponding power fuel of the connected combustion engine 25. In this (optional) embodiment, the metering unit 7 is composed of an injection valve. In the combustion chamber 5, the fuel is mixed with a gas containing oxygen, for example (process) air from the surrounding environment 26. The ignition unit 8 is (optionally) a spark plug and causes the gas-fuel mixture to burn in the combustion chamber 5. The cooling circuit 9 includes cooling lines (in the outer wall 4), which surround the metering unit 7 and the ignition unit 8 in as close contact as possible, so that as direct heat exchange as possible can be achieved. The structure of the cooling circuit 9 is described more precisely below. A coolant is conducted in a closed circuit 9, wherein the coolant is provided by means of an external coolant source. The coolant is, for example, water or a mixture of water and a cooling water additive, which is common in combustion engines. Preferably, the coolant source is the same coolant source as the coolant source used for cooling the connected combustion engine 25, for example, integrated in a temperature management module [Temperatur Management Module, TMM].

[0058] exist Figure 2 In the figure, the rear view of the connection side is shown according to Figure 1 Exhaust burner 1. In this view, two external interfaces 10, 11 of the cooling lines inside the burner can be seen with an external coolant source (not shown). In one embodiment, the (first) external interface 10 on the left side according to the illustration is an inlet, and the (second) external interface 11 on the right side according to the illustration is an outlet, so that firstly the ignition unit 8 is exchanged with heat via the first connecting line 17, and then the metering unit 7 is exchanged with heat via the second connecting line 18, and then the coolant flows out of the second external interface 11 again via the third connecting line 19. Therefore, the coolant is already heated at the metering unit 7, whereby the process air is preheated and a better homogenization of the air-fuel mixture supplied to the combustion chamber 5 is achieved.

[0059] The metering unit 7 is arranged in the metering unit assembly 14, wherein the metering unit assembly 14 includes a (second) cooling cover 15 and a holder 16. The holder 16 forms a metering unit receptacle 24 so as to simultaneously realize heat exchange and retention of the metering unit 7. The second cooling cover 15 has, for example, a channel wall on the cooling side (i.e., pointing toward the metering unit 7), which is adapted to conduct heat as well as possible. This channel wall is adapted, for example, to be thin-walled, to have a corresponding (close) form and / or to accommodate heat-conducting paste. At least one cooling cover 15 is implemented as a closed-chamber pipeline element according to the proposal. The remaining components of the cooling pipeline are connected to the second cooling cover 15 in a fluid-tight manner, and the second cooling cover 15 is arranged to surround the metering unit 7.

[0060] exist Figure 3 In the top view, the Figure 1 and Figure 2 The exhaust gas burner 1 is shown in FIG. 1 . The first external interface 10 is arranged at the lower right of the metering unit 7 in this illustration and is connected to the first cooling hood 13 (as tightly as possible) surrounding the ignition unit 8 via a first connecting line 17 inside the burner, i.e. arranged in the outer wall 4 of the exhaust gas burner 1. In this illustration, the second external interface 11 is also arranged on the right and is connected to the second cooling hood 15 above the metering unit 7 via a third connecting line 19 inside the burner, i.e. arranged in the outer wall 4 of the exhaust gas burner 1. The first cooling hood 13 is connected to the second cooling hood 15 by means of a second connecting line 18. In one embodiment, the first connecting line 17 and the second connecting line 18 inside the burner are pre-assembled or connected in one piece to the first cooling hood 13.

[0061] The first cooling jacket 13 is here (optionally) part of the ignition unit arrangement 12. The ignition unit receptacle 20 is here formed by the inner wall 21 of the combustion chamber 5, for example as a welded, gas-tight and pressure-tight pipe for screwing in the ignition unit 8. The ignition unit arrangement 12 comprises a first cooling jacket 13 which is adapted for an indirect heat exchange with the ignition unit 8, for example by means of the ignition unit receptacle 20 (for example the pipe mentioned).

[0062] exist Figure 4 In the figure, it is shown that in the channel section 6 there is a Figure 3 The motor vehicle 3 comprises a combustion engine 25 (adapted to be driven by means of two drive wheels 27, 28) with an exhaust system 2. In the exhaust system 2, the exhaust gas produced when the power fuel is burned is aftertreated and discharged to the surrounding environment 26 via (optionally two) tail pipes 29.

[0063] exist Figure 5The example used for (for example, in Figures 1 to 3 Flow chart of an assembly method for an exhaust gas burner 1 with an integrated cooling circuit 9 (shown in FIG. 1 ). In step a, the ignition unit assembly 12 is preferably placed together with the structurally integrated, burner-internal connecting lines 17, 18 on the ignition unit 8 and / or on the ignition unit receptacle 20 in the inner wall 21 of the combustion chamber 5. In this exemplary embodiment, at the same time in step b, the internal interfaces 22, 23 of the ignition unit assembly 12 placed in step a are oriented with respect to the burner-internal connecting lines 17, 18, and the burner-internal connecting lines 17, 18 connected to the ignition unit assembly 12 are brought into a position exposed in the final state of the exhaust gas burner 1. In this exemplary embodiment, subsequently in step c, the metering unit assembly 14 is preferably placed together with the structurally integrated, burner-internal third connecting line 19 and / or second connecting line 18 on the metering unit 7 and / or on the metering unit receptacle 24 in the outer wall 4 of the exhaust gas burner 1. Furthermore, in step d, a cooling circuit 9 inside the burner is formed by means of at least a fluid connection of the second connecting line 18 with the metering unit assembly 14. Finally, in step e, the exhaust gas burner 1 is closed. Preferably, the first external interface 10 and the first connecting line 17, and / or the second external interface 11 and the third connecting line 19 are already integrally formed (e.g., in one piece) before installation.

[0064] With the exhaust gas burner proposed here, good cooling and cost-effective production and simple assembly thereof can be achieved.

[0065] List of Reference Numerals

[0066] 1 Exhaust burner

[0067] 2 Exhaust system

[0068] 3 Motor vehicles

[0069] 4 outer wall

[0070] 5 Combustion Chamber

[0071] 6-channel segment

[0072] 7 Measuring unit

[0073] 8 Ignition unit

[0074] 9 Cooling circuit

[0075] 10 First external interface

[0076] 11 Second external interface

[0077] 12 Ignition unit assembly

[0078] 13. First cooling hood

[0079] 14 Metering unit assembly

[0080] 15 Second cooling hood

[0081] 16 Holder

[0082] 17 First connecting pipeline

[0083] 18 Second connecting pipeline

[0084] 19 Third connecting pipeline

[0085] 20 Ignition unit housing

[0086] 21 Inner wall

[0087] 22 First internal interface

[0088] 23 Second internal interface

[0089] 24 Measuring unit housing

[0090] 25 Combustion Power Engine

[0091] 26 Surroundings

[0092] 27 Left drive wheel

[0093] 28 Right drive wheel

[0094] 29 Tail pipe

Claims

1. An exhaust gas burner (1) for an exhaust system (2) of a motor vehicle (3), the exhaust gas burner having at least the following components: - a combustion chamber (5) enclosed by an outer wall (4) and serving as a channel section (6) in the exhaust system (2); - a metering unit (7) for the controlled addition of fuel into the combustion chamber (5); and - an ignition unit (8) for igniting the combustible mixture in the combustion chamber (5), It is characterized in that A cooling circuit (9) is also arranged in the outer wall (4) of the exhaust gas burner (1), and is used for heat exchange with the metering unit (7) and the ignition unit (8). wherein, in the cooling circuit (9), the ignition unit (8) and the metering unit (7) are arranged to be connected in series with each other, and the ignition unit (8) is connected before the metering unit (7) in the flow direction, And wherein the cooling circuit (9) is modularly constructed and comprises only the following modules: i. an ignition unit assembly (12), the ignition unit assembly having a first cooling hood (13) for the ignition unit (8); ii. a metering unit assembly (14) having a second cooling hood (15) for the metering unit (7) and having a holder (16) for the metering unit (7); and iii. a second connecting line (18) inside the exhaust burner, which connects the ignition unit assembly (12) and the metering unit assembly (14) in a flow sense, The second connecting pipeline (18) inside the exhaust burner is integrally contained in the ignition unit assembly (12).

2. The exhaust gas burner (1) according to claim 1, wherein The cooling circuit (9) comprises a ventilation device.

3. The exhaust gas burner (1) according to claim 1 or 2, wherein The cooling circuit (9) has two external connections (10, 11) to which an external coolant source can be connected outside the combustion chamber (5).

4. The exhaust gas burner (1) according to claim 1 or 2, wherein The cooling circuit (9) comprises at least one section, which comprises half shells and / or closed-chamber pipeline elements. The half shells and / or closed-chamber line elements are connected to one another in a materially bonded manner.

5. The exhaust gas burner (1) according to claim 4, wherein The half shells and / or closed-chamber line elements are connected to one another by means of brazing.

6. A method for assembling an exhaust burner (1) for an exhaust system (2) of a motor vehicle (3) according to claim 1, wherein the method comprises at least the following steps: a. placing the ignition unit assembly (12) together with the second connecting line (18) and the first connecting line (17) which are integrally formed inside the exhaust burner onto the ignition unit (8) and / or onto the ignition unit receiving portion (20) in the inner wall (21) of the combustion chamber (5); b. orienting the internal interface (22, 23) of the ignition unit assembly (12) placed in step a relative to the second connecting line (18) and the first connecting line (17) inside the exhaust burner, and bringing the second connecting line (18) and the first connecting line (17) inside the exhaust burner connected to the ignition unit assembly (12) to a position where they are exposed in the final state of the exhaust burner (1); c. placing the metering unit assembly (14) onto the metering unit (7) and / or onto the metering unit receiving portion (24) in the outer wall (4) of the exhaust burner (1); d. forming the cooling circuit (9) inside the exhaust burner by means of fluid-tightly connecting the second connecting line (18) and the metering unit assembly (14); and e. After step d, close the exhaust burner (1).

7. The assembly method according to claim 6, wherein In an intermediate step d1 after step d and before step e, the formed cooling circuit ( 9 ) is checked for leaks.

8. The assembly method according to claim 6 or 7, wherein The modules are connected by means of welding.

9. The assembly method according to claim 8, wherein The modules are connected by means of soldering.

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