Burner for an exhaust tract through which exhaust gas from an internal combustion engine of a motor vehicle can flow

Abstract

The invention relates to a burner (10) for an exhaust tract through which exhaust gas from an internal combustion engine of a motor vehicle flows, comprising a combustion chamber (12) in which a mixture comprising air and a fuel is to be ignited and thereby burned, comprising at least one housing element (18) which at least partially delimits the combustion chamber (12), and comprising at least one outlet element (30) which has at least one through-opening (32) via which burner exhaust gas produced by the combustion of the mixture can be discharged from the combustion chamber (12) for heating the exhaust tract of the internal combustion engine, wherein at least one fastening region (34) via which the outlet element (30) is held on the housing element (18) to form a sliding fit.

Description

The invention relates to a burner for an exhaust tract through which exhaust gas of an internal combustion engine of a motor vehicle can flow, according to the preamble of patent claim 1.Such a burner is known from DE 10 2021 001 580 A1. The burner has at least one combustion chamber in which a mixture comprising air and a fuel, in particular liquid fuel, is to be ignited and thereby burned. In addition, the burner has at least one housing element, which can be referred to in particular as a combustion chamber housing. The housing element delimits the combustion chamber at least partially, in particular predominantly or completely, for example in the radial direction of the combustion chamber and / or in the axial direction of the combustion chamber. Furthermore, the burner has at least one outlet element, in particular an outlet element which delimits the combustion chamber at least partially, for example in the axial direction of the combustion chamber. The outlet element has at least one passage opening, via which burner exhaust gas generated by the burning of the mixture can be discharged from the combustion chamber for heating the exhaust tract of the internal combustion engine, in particular for heating at least one component arranged in the exhaust tract of the internal combustion engine, and can be introduced in particular into the exhaust tract or at least one longitudinal region of the exhaust tract. In particular, the outlet element is arranged on an outlet side of the combustion chamber, wherein the outlet side is, for example, an axial end side of the combustion chamber or of the housing element. The outlet side can be referred to in particular as the gas outlet side.It is an object of the present invention to provide a burner for an exhaust tract through which exhaust gas of an internal combustion engine of a motor vehicle can flow, such that a thermal load capacity of the burner can be particularly increased.This object is achieved according to the invention by a burner for an exhaust tract through which exhaust gas from an internal combustion engine of a motor vehicle can flow, having the features of patent claim 1. Advantageous embodiments with expedient developments of the invention are specified in the other claims.In order to create a burner of the type specified in the preamble of claim 1, so that a thermal load capacity of the burner, in particular of the outlet element and / or of the housing element, can be particularly increased, at least one fastening region is provided according to the invention, by means of which the outlet element is held, in particular for compensating thermal stresses or thermal expansions, on the housing element, in particular in a movable manner, for example at least indirectly or directly, while forming a sliding seat. In other words, clearance is provided, for example in the axial direction of the combustion chamber and / or in the radial direction of the combustion chamber, between the outlet element fastened to the housing element via the fastening region and the housing element, in order in particular to compensate for thermal stresses or thermal expansions.The fastening region can be understood in particular as a fastening region of the outlet element and / or of the housing element and / or of a fastening element formed separately from the outlet element and the housing element. The fastening region can thus be formed by the outlet element and / or the housing element and / or the fastening element.The sliding seat can be understood in particular as a sliding seat in order to compensate for differences in length, which are caused, for example, by thermal expansions, between the outlet element and the housing element. For example, the outlet element held or fastened to the housing element over the fastening region is expandable and / or compressible without stress in the event of a temperature change of the outlet element. Thus, the outlet element can expand, for example, without stress, in particular outwards, when the temperature rises, and the outlet element can, for example, contract again when the outlet element cools.For example, the outlet element is movable, in particular at least indirectly or directly, on the housing element via the fastening region in the radial direction of the combustion chamber and / or in the axial direction of the combustion chamber relative to the housing element. Particularly preferably, the outlet element is held on the housing element such that it can be moved via the fastening region, however, in the radial direction of the combustion chamber relative to the housing element. The sliding seat is thus, for example, a sliding seat provided or formed on the outer periphery of the outlet element.The invention is based in particular on the following findings and considerations: during operation of the burner, the combustion chamber can heat up particularly strongly, for example to up to 1150° C. As a result of a possible temperature difference, which can be particularly high and is, for example, almost 1,200 K, very high, in particular thermal, stresses can occur at a perforated outlet surface in the form of the outlet element having the at least one passage opening, which stresses can lead to cracks. A conventional burner can usually have a combustion chamber with a fixed geometry. Such a conventional burner can have a gas outlet with a planar outlet element connected to the burner or the housing element. This means that in the conventional burner no sliding seat or no clearance can be provided between the outlet element and the housing element. Thus, in the conventional burner, for example, during cooling, there may be a risk of cracking. Thermal stress cracks can therefore occur in the conventional burner.In contrast, by means of the burner according to the invention, the thermal load capacity of the burner, in particular of the outlet element and / or of the housing element, can be particularly increased. This can be achieved in particular in that the outlet element is held on the housing element via the fastening region, forming the sliding seat, in particular movable relative to the housing element, as a result of which the outlet element can move relative to the housing element in the event of a thermally induced change in length, in particular in order to contract and / or expand. By means of the outlet element with sliding fit, for example on the outer periphery of the outlet element, thermal expansions between the outlet element (gas outlet) and the burner or the combustion chamber housing can be compensated, as a result of which thermal stresses and cracks can be avoided. It is therefore possible, for example, for the outlet element to be able to expand outwards without stress in the event of a temperature increase and to contract again on cooling, to avoid unacceptably high stresses in the outlet element. In particular, crack formation, for example in the outlet element, as a result of excessively high tensile stresses and / or excessively high compressive stresses can be prevented, above all during cooling of the combustion chamber. Overall, it can be seen that a burner with a sliding fit can be realized on the gas outlet side. By increasing the thermal load capacity of the burner, safety against damage to the burner can be particularly increased. In particular, a service life of the burner can be particularly increased.For example, the internal combustion engine, in particular in its completely produced state, has the burner, wherein the burner is preferably arrangeable or arranged in the exhaust tract of the internal combustion engine. The internal combustion engine preferably has at least one combustion chamber in which combustion processes take place in which a fuel-air mixture is to be burned or is burned. The combustion chamber is designed, for example, as a cylinder. The combustion chamber is formed separately from the burner. In particular, the combustion chamber and the burner are spaced apart from one another. The internal combustion engine preferably has at least one intake tract through which air can flow, via which intake tract air can be supplied to the combustion chamber. The exhaust gas of the internal combustion engine generated from the combustion of the fuel-air mixture in the combustion chamber can be discharged from the combustion chamber via the exhaust tract.The component, which is arranged in particular in the exhaust tract of the internal combustion engine, is preferably a catalytic converter. The catalyst can thus be heated by means of the burner, in particular by means of the burner exhaust gas generated in the combustion chamber of the burner.Further advantages, features and details of the invention are evident from the following description of preferred exemplary embodiments and on the basis of the drawings. The features and combinations of features mentioned above in the description and the features and combinations of features mentioned below in the description of the figures and / or shown alone in the figures can be used not only in the respectively specified combination but also in other combinations or alone without departing from the scope of the invention.The following are shown: FIG. 1 is a schematic partial sectional view of a burner according to the invention; and FIG. 2 shows a schematic detailed view of the burner according to the invention according to FIG. 1 ; and FIG. 3 is a schematic further partial sectional view of a burner according to the invention.In the figures, identical or functionally identical elements are provided with identical reference symbols.FIG. 1 shows a schematic partial sectional view of a burner 10 for an exhaust tract through which exhaust gas of an internal combustion engine of a motor vehicle can flow. The motor vehicle is designed, for example, as a motor vehicle, in particular as a passenger car or as a commercial motor vehicle. The motor vehicle can preferably be driven by means of the internal combustion engine.The exhaust tract can be understood in particular as an exhaust system of the internal combustion engine. In some operating states or operating situations of the internal combustion engine, a high temperature of the exhaust gas may be desirable in order to be able to quickly heat up and / or keep warm an exhaust gas aftertreatment device arranged in the exhaust tract, for example, wherein, however, the temperature of the exhaust gas is only insufficiently high in these operating states or operating situations. By means of the burner, the exhaust tract, and in particular the exhaust gas aftertreatment device, can be heated and / or kept warm. This means that the exhaust tract, in particular the exhaust gas aftertreatment device, can be heated and / or kept warm by means of the burner, for example in addition to heating and / or keeping warm by means of the exhaust gas. This exhaust gas can be understood to mean, in particular, an exhaust gas generated from a fuel-air mixture in a combustion chamber of the internal combustion engine. The combustion chamber, which is designed as a cylinder, for example, is designed separately from the burner 10.The internal combustion engine is designed, for example, as a diesel engine. The exhaust gas aftertreatment device comprises, for example, at least one catalytic converter or is designed as a catalytic converter. The exhaust gas aftertreatment device or the catalytic converter is designed, for example, as an oxidation catalytic converter, in particular a diesel oxidation catalytic converter, a nitrogen oxide storage catalytic converter, an SCR catalytic converter as a particle filter, in particular a diesel particle filter. The exhaust gas of the internal combustion engine can be purified by means of the exhaust gas aftertreatment device.The burner 10 has a burner housing 11 and a combustion chamber 12, in which an air and a mixture, in particular a liquid mixture, comprising fuel is to be ignited and thereby burned. This means that the burner 10 can ignite and combust the mixture in the combustion chamber 12, in particular with the formation of a flame and in particular with the provision of a burner exhaust gas.For example, the fuel is the fuel which is also burned in the combustion chamber, which is designed as a cylinder, for example, of the internal combustion engine. Thus, the fuel may be used as the fuel. However, the burner exhaust gas is not the exhaust gas generated in the combustion chamber of the internal combustion engine.In the exemplary embodiment, the burner 10 has an air feed 13 in the burner housing 11, by means of which or via which the air, in particular for forming the mixture, can be introduced into the combustion chamber 12, in particular directly. Furthermore, the air feed 13 can be closed by a flap 15 pivotably attached to the burner housing 11, in particular can be closed by the flap 15 with respect to the combustion chamber 12, so that, for example, no soot from the exhaust gas of the internal combustion engine can be deposited on and in the air feed 13, as a result of which a trouble-free function of the air feed 13 and of the burner 10 can be at least extended overall. The pivotable flap 15 is arranged in the combustion chamber 12.In the exemplary embodiment, the burner 10 furthermore has at least one introduction element 14, by means of which or via which the fuel, in particular for forming the mixture, can be introduced into the combustion chamber 12. The introduction element 14 is designed, for example, as an injection valve. The introducing element 14 initially injects the fuel into the air supply 13, after which the fuel is introduced together with the air from the air supply 13 directly into the combustion chamber 12.For example, the burner 10 has at least one ignition device, which is arranged in particular in the combustion chamber 12 and by means of which the mixture comprising the air and the fuel is to be ignited in the combustion chamber 12 and thereby burned. The ignition device is designed, for example, as a spark plug, glow plug or glow plug. The ignition device is arranged, for example, in an installation position 16 provided with the reference sign 16.The burner 10 has at least one housing element 18, which can be referred to in particular as a combustion chamber housing. The housing element 18 delimits the combustion chamber 12 at least partially, in particular predominantly. In the exemplary embodiment, the combustion chamber 12 or the housing element 18 is at least substantially cylindrical. Furthermore, in the exemplary embodiment, the housing element 18 has at least one side wall 20 which delimits the combustion chamber 12 at least partially, in particular predominantly or completely, in its radial direction 22. Furthermore, the housing element 18 has, for example, at least one base element 24, which at least partially delimits the combustion chamber 12 in its axial direction 26, in particular at one end. The combustion chamber 12 is delimited by the burner housing 11 opposite the base element 24 in the axial direction 26. The bottom element 24 and the side wall 20 can be formed together in one piece or can be formed separately from one another and are arranged rotationally symmetrically with respect to a central axis 27 of the burner 10. The bottom element 24 can be referred to in particular as a bottom wall. In the exemplary embodiment, the side wall 20 and the bottom element 24 are part of a lower housing part 28 of the housing element 18, wherein at least one upper housing part 29 of the housing element 18 adjoins the lower housing part 28, for example in the axial direction 26 in the direction away from the bottom element 24. The upper housing part 29 is connected integrally to the burner housing 11 in the exemplary embodiment shown. Overall, the combustion chamber 12 is delimited and formed, starting from the burner housing 11, the upper housing part 29 and the lower housing part 28 of the side wall 20 and the bottom element 24 of the housing element 18, as seen in the axial direction 26.FIG. 2 shows the burner 10, in particular the combustion chamber 12, in a schematic detailed view. The burner 10 has at least one outlet element 30, in particular the combustion chamber 12, preferably in the axial direction 26, which at least partially delimits an outlet element and has at least one through-opening 34, through which the burner exhaust gas, which is in particular able to be flown by the burner exhaust gas and via which the burner exhaust gas generated by the burning of the mixture can be or is discharged from the combustion chamber 12 for heating the exhaust tract of the internal combustion engine, in particular the exhaust gas aftertreatment device, and in particular can be or is introduced into the exhaust tract, for example for acting on the exhaust gas aftertreatment device. The burner exhaust gas or the flame can thus be discharged from the combustion chamber 12, in particular from the burner 10, via the passage opening 32, and in particular introduced into the exhaust tract, for example into at least one line element of the exhaust tract. The exhaust tract, and in particular the exhaust gas aftertreatment device, can be heated and / or kept warm by the burner exhaust gas or the flame.In order to be able to particularly increase a thermal load capacity of the burner 10, in particular of the outlet element 30 and / or of the housing element 18, at least one fastening region 34 is provided, by means of which the outlet element 30, in particular for compensating thermal stresses or thermal expansions, is held, in particular for the purpose of forming a sliding seat, in particular movably, on the housing element 18, for example on the base element 24, for example at least indirectly or directly. The outlet element 30 is movable relative to the housing element 18 and the base element 24, for example, at least in the radial direction 22 of the combustion chamber 12, in particular for compensating the thermal stresses or thermal expansions. For this purpose, a free space 36, for example, is provided in the radial direction 22 of the combustion chamber 12 or of the outlet element 30 and of the housing element 18, in particular of the side wall 20. The thermal stresses or the thermal expansions can be understood to mean, in particular, thermal stresses of the outlet element 30 or thermal expansions of the outlet element 30.For example, at least one holding device 38 is provided, which is formed in particular separately from the outlet element 30 and the housing element 18 and by means of which the outlet element 30 is held on the housing element 18 while forming the sliding seat, in particular movably. Thus, the fastening region 34 can be formed at least partially by the holding device 38 or the holding device 38 can have the fastening region 34. The holding device 38 can be understood in particular as a bearing device which can also simply be referred to as a bearing. Alternatively or additionally, the outlet element 30 is welded, for example, via the fastening region 34 to the housing element 18, in particular to the base element 24, that is to say is fastened, for example, by means of a weld or a welding point 40 to the housing element 18, in particular to the base element 24. The fastening region 34 is preferably located on the central axis 27.In the exemplary embodiment, it is provided that the outlet element 30 has a plurality of through openings 32, via which the burner exhaust gas or the flame for heating the exhaust tract of the internal combustion engine, in particular the exhaust gas aftertreatment device, can be discharged from the combustion chamber 12, in particular from the burner 10, and can be introduced, for example, into the exhaust tract or into the line element. As a result, the exhaust tract, in particular the exhaust gas aftertreatment device, can be particularly well heated or kept warm. The passage openings 32 can be flowed through by the burner exhaust gas.FIG. 3 shows the burner 10, in particular the outlet element 30, in a schematic partial sectional view, in particular viewed from above. In the exemplary embodiment, eight of the through openings 32 are provided. The respective through-opening 32 can be understood to mean, for example, a respective bore which can be referred to in particular as a through-opening. The through-openings 32 are arranged overlapping with floor element openings 42 between floor element struts 44 of the floor element 24. The floor element struts 44 connect a floor element middle part 46 to a floor element edge part 48, wherein the floor element struts 44, the floor element middle part 46 and the floor element edge part 48 are aligned symmetrically to the central axis 27. The fastening region 34 is provided on the floor element middle part 46.For example, the outlet element 30 is plate-shaped, i.e. designed as a plate, which can be referred to in particular as an outlet plate. In the exemplary embodiment, the outlet element 30 is designed in the form of a circular perforated plate, in particular as a perforated disk.In the exemplary embodiment, it is provided that the through-openings 32 are arranged in the circumferential direction 50 of the combustion chamber 12 in an equally distributed manner. The through openings 32 are arranged in particular along an, in particular imaginary, circle, the center point of which is arranged on the center axis 27 of the combustion chamber 12. An axial direction 52 of the respective through-openings 32 preferably runs parallel to the axial direction 26 of the combustion chamber 12.In the exemplary embodiment, it is provided that an edge region 54 of the outlet element 30, which edge region is related to the radial direction 22 of the combustion chamber 12 or the radial direction of the outlet element 30, bears in the axial direction 52 of the, in particular respective, through-opening 32 with the formation of a sealing region 56, in particular the housing element 18, for example the base element 24, overlapping, for example directly, on the housing element 18, in particular on the base element 24, in the axial direction 52 of the through-opening 32. As a result, a tight connection can be created between the outlet element 30 and the housing element 18, in order to prevent, for example, undesired gas discharge, bypassing the respective through-opening 32. The sealing region 56 can be referred to in particular as a "sealing region for sliding fit" and is designed in the form of a circumferential shoulder in the direction of the burner housing 11.In the exemplary embodiment, the outlet element 30 is formed on the inside with respect to the housing element 18, that is to say as an inner component. The outlet element 30 is thus arranged further inward in the radial direction 22 and / or in the axial direction 26 of the combustion chamber 12 than the housing element 18.In the exemplary embodiment, it is provided that the outlet element 30 is supported, for example at least indirectly or directly, on the housing element 18, in particular on the sealing region 56 of the base element 24, in the flow direction 58 of the burner exhaust gas discharged from the combustion chamber 12 via the, in particular respective, through-opening 32 or of the burner flame discharged via the respective through-opening 32. As a result, a particularly stable and / or particularly tight connection can be created between the outlet element 30 and the housing element 18. The flow direction 58 preferably extends parallel to the axial direction 54.In the exemplary embodiment, it is provided that the fastening region 34, in particular the holding device 38 and / or the welding point 40, is arranged at least substantially centrally on the central axis 27 of the burner 10 on the housing element 18, in particular on the bottom element 24 and on the outlet element 30, with respect to the radial direction 22 of the combustion chamber 12. The fastening region 34 can thus be understood to mean, for example, a central connection for avoiding thermal stresses.List of reference characters10 Burner 11 Burner housing 12 Combustion chamber 13 Air feed 14 Introduction element 15 Flap 16 Installation position 18 Housing element 20 Side wall 22 Radial direction of the combustion chamber 24 Base element 26 Axial direction of the combustion chamber 27 Central axis 28 Housing lower part 29 Housing upper part 30 Outlet element 32 Through opening 34 Fastening region 36 Free space 38 Holding device 40 Welding point 42 Base element opening 44 Base element struts 46 Base element central part 48 Base element edge part 50 Circumferential direction 52 Axial direction of the through opening 54 Edge region 56 Sealing region 58 Flow directionReferences included in the specificationThis list of documents cited by the applicant has been produced in an automated manner and is only included for the better information of the reader. The list is not part of the German patent application or utility model application. The DPMA does not take any adhesion for any faults or omissions.Patent Literature citedDE 10 2021 001 580 A1

[0002]

Claims

Burner (10) for an exhaust tract through which exhaust gas from an internal combustion engine of a motor vehicle can flow, having a combustion chamber (12) in which a mixture comprising air and a fuel can be ignited and thereby burned, having at least one housing element (18) which at least partially delimits the combustion chamber (12), and having at least one outlet element (30) which has at least one through opening (32) via which burner exhaust gas generated by the burning of the mixture can be discharged from the combustion chamber (12) for heating the exhaust tract of the internal combustion engine, characterized byat least one fastening region (34) via which the outlet element (30) is held on the housing element (18) forming a sliding seat.Burner (10) according to Claim 1, characterized in that the outlet element (30) has a plurality of passage openings (32) via which the burner exhaust gas can be discharged from the combustion chamber (12) in order to heat the exhaust tract of the internal combustion engine.Burner (10) according to Claim 2, characterized in that the outlet element (30) is designed as a perforated plate.Burner (10) according to Claim 2 or 3da characterized in that the passage openings (32) are arranged in a uniformly distributed manner in the circumferential direction (50) of the combustion chamber (12).Burner (10) according to one of the preceding claims, characterized in that an edge region (54) of the outlet element (30), which edge region is referred to a radial direction (22) of the combustion chamber (12), bears against the housing element (18) in the axial direction (52) of the through-opening (32), forming a sealing region (56).Burner (10) according to one of the preceding claims, characterized in that the outlet element (30) is supported on the housing element (18) in the flow direction (58) of the burner exhaust gas discharged via the through-opening (32).Burner (10) according to one of the preceding claims, characterized in that the fastening region (34) is arranged centrally on the housing element (18) with respect to a radial direction (22) of the combustion chamber (12).

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