Burner for a motor vehicle as well as motor vehicle

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 fuel is to be ignited and thereby combusted; a component (38) which directly delimits at least one channel (22) through which at least a portion of the air can flow, and through which the air flowing through the channel (22) can be supplied to the combustion chamber (12); and an introduction element (28) by means of which the fuel can be introduced into the channel (22); wherein the channel (22) is directly delimited by an inner circumferential surface (40) of the component (38), wherein at least a partial area (TB1) of the surface (40) is provided with a specifically manufactured surface structure (44).

Description

[0001] The invention relates to a burner for an exhaust tract through which exhaust gas from an internal combustion engine of a motor vehicle flows, according to the preamble of claim 1. Furthermore, the invention relates to a motor vehicle with at least one such burner.

[0002] DE 10 2021 001 580 A1 discloses a burner for an exhaust tract through which exhaust gas from an internal combustion engine of a motor vehicle flows, comprising a combustion chamber in which a mixture comprising air and a fuel is to be ignited and thereby combusted. Furthermore, EP 1 391 653 A2 discloses a prefilmer for a fuel injection arrangement.

[0003] The object of the present invention is to create a burner for a motor vehicle and a motor vehicle with at least one such burner, so that a particularly advantageous operation of the burner can be realized.

[0004] This problem is solved by a burner with the features of claim 1 and by a motor vehicle with the features of claim 10. Advantageous embodiments with expedient further developments of the invention are specified in the remaining claims.

[0005] A first aspect of the invention relates to a burner for an exhaust tract through which exhaust gas flows from an internal combustion engine, also referred to as an internal combustion engine or motor, and preferably a reciprocating engine, i.e., a piston engine, of a motor vehicle, also simply referred to as a vehicle. This means that the motor vehicle, which may preferably be a motor vehicle and most preferably a passenger car or a commercial vehicle, in its fully manufactured state comprises the internal combustion engine and the exhaust tract and can be driven by means of the internal combustion engine. During operation of the internal combustion engine, combustion processes take place in the internal combustion engine, in particular in at least one or more combustion chambers of the internal combustion engine, resulting in the exhaust gas of the internal combustion engine, also referred to as engine exhaust.The engine exhaust gas can flow out of the respective combustion chamber and into the exhaust system, subsequently flowing through the exhaust system. At least one component, such as an exhaust aftertreatment element, can be located in the exhaust system for treating the exhaust gas. The exhaust aftertreatment element is or includes, for example, a catalyst, in particular an SCR catalyst, whereby, for example, a selective catalytic reduction (SCR) process can be catalytically supported and / or effected by means of the SCR catalyst, such that, for example, the SCR catalyst is catalytically active for the SCR process. During selective catalytic reduction, any nitrogen oxides contained in the engine exhaust gas are at least partially removed from the exhaust gas by reacting the nitrogen oxides with ammonia to form nitrogen and water.The ammonia is provided, for example, by a reducing agent, which is primarily liquid and could be an aqueous urea solution. Furthermore, it is conceivable that the exhaust aftertreatment element is a particulate filter or includes a particulate filter. Most specifically, the particulate filter is a diesel particulate filter (DPF). The particulate filter can remove any particles, especially soot particles, that may be present in the exhaust gas.

[0006] The burner has a combustion chamber, also referred to as the main combustion chamber, in which a mixture, also referred to as the burner mixture, comprising air and a preferably liquid fuel, can be ignited and thereby combusted. The aforementioned air forming the mixture (burner mixture) is also referred to as burner air. In particular, the combustion chamber is delimited by a chamber element, especially one designed as a solid, and in particular by an inner circumferential surface of the chamber element, especially directly. The combustion of the mixture, which takes place particularly in the combustion chamber, produces burner exhaust gas, also referred to as burner exhaust gas.The burner exhaust gas can, for example, flow out of the combustion chamber and into the exhaust system, that is, into an exhaust channel of the exhaust system through which the engine exhaust gas flows, particularly at an inlet point that is located upstream of the aforementioned component in the direction of flow of the engine exhaust gas through the exhaust system or exhaust channel. For example, the burner exhaust gas mixes with the engine exhaust gas. Consequently, the burner exhaust gas, especially the hot burner exhaust gas mixed with the engine exhaust gas, can flow through the component, thereby heating it up.In particular, it is conceivable that the hot burner exhaust gas can flow out of the combustion chamber and into the exhaust system or the aforementioned exhaust duct, thereby mixing with the engine exhaust gas and / or gas flowing through the exhaust system, thus heating the engine exhaust gas or the gas. In other words, this can result in a particularly high temperature of the engine exhaust gas or the gas, also known as the exhaust gas temperature.In particular, the gas can be, for example, air flowing through the exhaust system or exhaust duct, especially while the internal combustion engine is being towed, i.e., when the engine is not firing and therefore not producing exhaust gas. In this case, the gas, especially air, is forced through the exhaust system by the engine. The high exhaust gas temperature can heat and / or keep the component warm, as the burner exhaust and, for example, the engine exhaust or gas flow through it. Thus, for example, the burner exhaust from the combustion chamber is introduced into the exhaust system, specifically the exhaust duct, at the aforementioned inlet point, and consequently into the engine exhaust or gas flowing through the exhaust system or exhaust duct.

[0007] The burner has at least one channel through which at least a portion of the air flows. The aforementioned portion of air is also referred to as the first portion of air. Whenever the term "part of air" is used before and below, it refers, unless otherwise specified, to the first portion of air. The channel is also referred to as the first channel. Whenever the term "channel" is used before and below, it refers, unless otherwise specified, to the first channel. Whenever the term "air" is used before and below, it refers, unless otherwise specified, to the air that forms the mixture, which is also referred to as burner air. The burner has a solid component that directly delimits the channel.In particular, the channel is directly bounded by an inner circumferential surface of the component, preferably a concave surface. In other words, the inner circumferential surface of the component is a surface of the component whose surface directly bounds the channel and, in particular, is concave. For example, the channel has at least one or exactly one outlet opening through which the air flowing through the channel can be discharged from the channel and thus supplied to the combustion chamber, and in particular introduced into the combustion chamber. In general terms, the air flowing through the channel can be supplied to the combustion chamber, and in particular introduced into the combustion chamber. The aforementioned outlet opening is also referred to as the first outlet opening.When the term "outflow opening" is used before and below, it refers, unless otherwise specified, to the first outflow opening.

[0008] For example, the burner also has an ignition device, particularly one that is electrically operated, by means of which the mixture, especially in the combustion chamber, can be ignited. It is particularly conceivable that the ignition device is at least partially located in the combustion chamber. By means of the ignition device, at least one ignition spark can be provided, i.e., generated, for igniting the mixture, particularly in the combustion chamber and / or using electrical energy with which the ignition device can be supplied or is supplied, so that the mixture, especially in the combustion chamber, can be ignited and subsequently burned, particularly by means of the ignition spark. The ignition device can, for example, be designed as a spark plug, a glow plug, or a glow pin.In particular, the ignition device can be used to ignite the mixture at at least or exactly one ignition point, for example in such a way that the ignition spark can be generated at the ignition point by means of the ignition device.

[0009] The burner also has an injection element by means of which the fuel can be introduced into the channel at least indirectly, in particular directly, and especially injected.

[0010] The channel is designed, for example, to create a swirling flow, also known as the first swirling flow, of the initial portion of air flowing through the channel. For this purpose, the channel may include a swirl chamber, also referred to as the first swirl chamber, which facilitates this initial swirling flow. The first swirl chamber is, for example, an internal swirl chamber, which will be explained in more detail below. The first channel, and thus the first swirl chamber, is arranged upstream of the combustion chamber in the direction of airflow. This flow direction is also referred to as the first flow direction.Thus, for example, the first swirl chamber has a first outlet opening through which the air flowing through the first channel and thus the first swirl chamber can flow, and through which the air flowing through the first outlet opening, i.e., the first part of the air, can be discharged from the first channel and thus from the first swirl chamber and, for example, introduced into the combustion chamber. Thus, the combustion chamber is arranged downstream of the first channel and, in particular, downstream of the first swirl chamber in the direction of airflow through the first channel and thus the first swirl chamber.The characteristic that the first swirl chamber causes or can cause the aforementioned first swirl flow of the air flowing through the first channel and thus the first swirl chamber means in particular that the first part of the air, i.e. the air flowing through the first channel, flows through the first swirl chamber in a swirl pattern, thus flowing through at least a first sub-area of ​​the first swirl chamber in a swirl pattern, and / or the first part of the air, i.e. the air flowing through the first channel, only exhibits its first swirl flow at least in a first flow region located downstream of the first swirl chamber and outside the first swirl chamber, which is, for example, located in the combustion chamber.In particular, it is conceivable that the first part of the air flows out of the first swirl chamber via the first outlet opening in a swirling motion and / or flows into the combustion chamber in a swirling motion, so that it is most preferably provided that the first part of the air, i.e., the air flowing through the first channel, exhibits its first swirling flow at least in the combustion chamber. In particular, it is conceivable that the first part of the air already exhibits its first swirling flow in the first swirl chamber, specifically at least in the aforementioned first sub-section of the first swirl chamber.

[0011] The fuel can be introduced, for example, at an injection point by means of the injection element, and in particular, injected. For example, the injection element is an injection element by means of which the fuel can be introduced, and in particular injected, at the injection point. In particular, the injection element can, for example, inject the fuel from itself at the injection point. The injection element has, for example, at least or exactly one outlet opening through which the preferably liquid fuel can flow. In particular, it is conceivable that the injection element has several, in particular more than two, outlet openings through which the preferably liquid fuel can flow. The fuel can be introduced, and in particular injected, at the injection point by means of the injection element.In particular, the injection element can spray the fuel flowing through it out of its respective outlet opening.

[0012] For example, the burner can have a second channel through which a second portion of the mixture-forming air (burner air) can flow, particularly in a second flow direction. For example, the second channel is designed to create a second swirl flow of the second portion of air. For this purpose, the second channel has, for example, a second swirl chamber by means of which the second swirl flow of the second portion of air (burner air) can be effected. If, for example, the first swirl chamber is the aforementioned inner swirl chamber, then, for example, the second swirl chamber is an outer swirl chamber. The outer swirl chamber surrounds, for example, at least a longitudinal region of the inner swirl chamber and preferably also the first outlet opening in the circumferential direction of the inner swirl chamber, in particular completely around it.The second channel, and thus, for example, the second swirl chamber, is permeable to the second portion of air flowing in the aforementioned second flow direction, with the first and second flow directions preferably coinciding. In particular, the flow directions point in the same direction. Most specifically, it is provided that the aforementioned circumferential direction of the inner swirl chamber runs around the first flow direction. For example, it is provided that, viewed in the second flow direction, the second channel, and thus, for example, the second swirl chamber, is arranged upstream of the combustion chamber, which, viewed in the second flow direction, is thus arranged downstream of the second channel, and thus, for example, the second swirl chamber. When the term "flow direction" is used before and below, it refers, unless otherwise specified, to the first flow direction.The circumferential direction of the inner swirl chamber, for example, runs around the first flow direction, which, for example, runs in the axial direction of the inner swirl chamber and thus of the first outlet opening, and therefore coincides with the axial direction of the inner swirl chamber, whose radial direction is perpendicular to the axial direction of the inner swirl chamber and thus of the first outlet opening. In particular, for example, the first flow direction runs in the axial direction of the first swirl chamber, whose radial direction is perpendicular to the axial direction of the first swirl chamber. Furthermore, it is conceivable that the first flow direction coincides with the axial direction of the first swirl chamber. Furthermore, for example, the second flow direction runs in the axial direction of the second swirl chamber, whose radial direction is perpendicular to the axial direction of the second swirl chamber.In particular, the second flow direction coincides with the axial direction of the second swirl chamber. Preferably, the first swirl chamber terminates at the first outlet or its end, in the direction of flow of the first portion of air passing through the first outlet opening, i.e., in the axial direction of the first swirl chamber and thus of the first outlet opening. The second swirl chamber, whose axial direction coincides with that of the first swirl chamber, is permeable to the second portion of air in the second flow direction and is designed, for example, to generate the second swirl flow of the second portion of air.This means, in particular, that the second part of the air flows in a swirling pattern in the second swirl chamber, thus flowing in a swirling pattern through at least a second sub-region of the second swirl chamber, and / or that the second part of the air exhibits its second swirling flow in a second flow region located downstream of the second swirl chamber in the direction of flow of the second part of the air flowing through the second swirl chamber, which may coincide with the aforementioned first flow region, wherein the second flow region may, for example, be located outside the second swirl chamber and, for example, inside the combustion chamber. Furthermore, it is conceivable that the aforementioned first flow region is located outside the second swirl chamber.In other words, it is conceivable that the second part of the air flows out of the second swirl chamber in a swirling pattern and / or flows into the combustion chamber in a swirling pattern, so that it is preferably provided that the second part of the air has its second swirling flow at least in the combustion chamber.

[0013] For example, the channel, in particular the second swirl chamber, has a second outlet opening through which the second part of the air flowing through the second channel and thus, for example, the second swirl chamber, and the first part of the air flowing through the first swirl chamber and the first outlet opening can flow, and which is arranged, for example, downstream of the first outlet opening in the direction of flow of the parts of the air, through which the second part of the air can be discharged from the second swirl chamber and the parts of the air can be supplied to the combustion chamber, in particular introduced into the combustion chamber.Since, for example, the fuel can be introduced, in particular by means of the injection element, at least indirectly, in particular directly, into the first channel, especially by bypassing the combustion chamber, the first outlet opening can be permeated, in particular in the first flow direction, by both the first part of the air, i.e., both by the air flowing through the first channel and by the fuel, so that, as a consequence, the second outlet opening can be permeated by both the second part of the air and by the first part of the air and also by the fuel, especially in the second flow direction.Thus, it is specifically provided that during operation of the burner, the air flowing through the first channel flows in the first flow direction through the first channel and, in particular, through the first outlet opening, and, for example, during operation, the fuel flows in the first flow direction through the first channel and, in particular, through the first outlet opening. During operation, the second part of the air flows in the second flow direction through the second channel and, in particular, through the second outlet opening, and, for example, the portions of air and fuel flow in the second flow direction through the second outlet opening.

[0014] In particular, it is conceivable that the second part of the air flows out of the second swirl chamber via the second outlet opening in a swirl pattern and / or flows into the combustion chamber in a swirl pattern, so that it is most preferably provided that the second part of the air has its second swirl-shaped flow at least in the combustion chamber.

[0015] In particular, it can be provided that the combustion chamber is arranged downstream of the first swirl chamber and / or downstream of the second swirl chamber in the flow direction of the respective portion of air flowing through the respective swirl chamber. Specifically, the combustion chamber is arranged downstream of the respective channel in the flow direction of the respective portion of air flowing through the respective channel. In particular, the portions of air, and especially the fuel, from the first channel can flow along the second flow direction, particularly in the second flow direction, through the second outlet opening and thus be fed to the combustion chamber via the second outlet opening, particularly flowing into the combustion chamber, wherein, for example, the second flow direction runs parallel to the first flow direction or coincides with the first flow direction.In particular, the first and second flow directions run along a common straight line. Furthermore, it is preferably provided that the second flow direction runs in the axial direction of the second swirl chamber, thus coinciding with the axial direction of the second swirl chamber, whose radial direction is perpendicular to the axial direction of the second swirl chamber, so that, for example, the radial direction of the second swirl chamber coincides with the radial direction of the first swirl chamber and vice versa. Thus, it is most preferably provided that the axial direction of the first swirl chamber corresponds to the axial direction of the second swirl chamber, or vice versa. Furthermore, it is preferably provided that the radial direction of the second swirl chamber coincides with the radial direction of the first swirl chamber and vice versa.In other words, it is preferably provided that the radial direction of the first swirl chamber corresponds to the radial direction of the second swirl chamber and vice versa. The respective axial direction of each swirl chamber is perpendicular to the respective radial direction of the respective swirl chamber, with the radial direction of the first swirl chamber coinciding with the radial direction of the second swirl chamber and vice versa. Since, for example, the second outlet opening is arranged along the respective flow direction, that is, in the flow direction of the respective portion of air downstream of the first outlet opening, and since preferably the second swirl chamber or the outer swirl chamber surrounds the first outlet opening, the first outlet opening is, for example, arranged in the second swirl chamber, particularly in the outer swirl chamber.In particular, it is conceivable that the second swirl chamber ends at the second outlet, especially at its end, particularly in the direction of flow of the second part of the air flowing through the second outlet.

[0016] For example, in order to generate the respective swirling flow of the respective part of the air, the respective swirl chamber has a respective swirl generation device by means of which the respective swirling flow of the respective part of the air can be effected.

[0017] To achieve particularly advantageous operation of the burner, the invention provides that at least a portion of the inner circumferential surface of the component, directly bordering the channel, is provided with a specifically manufactured surface structure, also referred to as surface structuring. This allows for the generation of particularly advantageous turbulence in the air flowing through the channel, thus enabling particularly advantageous mixture formation. For example, the surface structure is a microstructure, also referred to as microstructuring, which is a microscopically fine structure detectable only with optical aids.

[0018] Since the preferably liquid fuel can be introduced, at least indirectly, and in particular directly, into the channel by means of the introduction element, the inner circumferential surface of the component can, for example, be wetted with the fuel, particularly liquid, by introducing the fuel into the channel. In other words, for example, the fuel can be applied to the inner circumferential surface of the component by introducing the fuel into the channel.Since the air flowing through the channel flows in the aforementioned direction, it also transports the fuel through the channel in that direction. This means that the fuel applied to the inner surface of the channel flows along this surface in the direction of flow, directly touching it. For example, the fuel applied to the inner surface forms a film, also known as a fuel film, which is transported through the channel by the air flowing through it. This film then flows along the inner surface in the direction of flow, directly touching it.The channel and, for example, the component terminate, particularly when viewed in the direction of flow, at a separation edge of the component. This separation edge, for example, completely and / or directly delimits the outlet opening in the circumferential direction of the channel, extending around the direction of flow. Specifically, the separation edge is located at an end of the channel facing the combustion chamber, where, viewed in the first direction of flow, the channel terminates. The air flowing through the channel, that is, the aforementioned flow of air through the channel, and especially the fuel, particularly the fuel film, can detach from the separation edge, thus separating from the component at or over the separation edge. This can, for example, lead to the formation of fuel droplets.Due to its specifically designed surface structure, the air flowing through the channel exhibits a particularly advantageous flow, especially a particularly advantageous turbulent flow, which allows the droplets to form and mix with the air in a particularly efficient manner. This, in turn, enables the combustion mixture to be formed particularly efficiently. Since this component is used, for example, to form the fuel film, it is also referred to as a prefilmer. Whenever the term "prefilmer" is used before and after, it refers to this component.

[0019] The invention is based in particular on the following findings and considerations: To achieve particularly low-emission operation of the internal combustion engine, especially during a cold start, a burner is used by means of which the component can be heated effectively and efficiently, particularly during a cold start. This is especially advantageous if the internal combustion engine is a diesel engine and / or if the vehicle is heavy and, for example, a commercial vehicle. The burner allows the component to be maintained within an advantageous temperature range and / or brought into the temperature range in which it can effectively treat the exhaust gas. The burner enables the component to be heated and / or kept warm without causing significant emissions.In conventional solutions, droplet statistics, also known as droplet statistics, are not very specific, so the burner or its operation can be very sensitive to environmental parameters.

[0020] For example, the injection element can eject the fuel, forming a jet also known as a fuel jet. This jet is conical, for instance, resembling a cone or truncated cone. Typically, the flow geometry is designed, including the cone angle and / or diameter of the cone or truncated cone, based on the required swirl and burner output, and thus on the mass flow rate of the air, also referred to as the air mass flow rate.However, it has unfortunately been shown that the resulting surface area of ​​the component within the target performance range of the burner is very small, and consequently, severe misfires due to insufficient or inadequate mixture formation can repeatedly occur, particularly when the vehicle is at high altitude and / or when very low temperatures prevail in the vehicle's environment. The invention makes it possible to resolve the conflict between the aforementioned design and the insufficient active surface area by providing at least the portion of the inner circumferential surface of the component with the specifically manufactured surface structure.The characteristic that the surface structure is intentionally produced means that the inner circumferential surface does not exhibit the surface structure randomly, i.e., not due to random effects, but rather the surface structure is or is intentionally produced as part of a burner manufacturing process, in particular by, especially, mechanical machining of the inner circumferential surface. The surface structure is an intentionally produced imperfection that, compared to conventional solutions, leads to a significantly increased turbulence in the airflow through the channel. The mechanical machining process includes, for example, turning.

[0021] In order to form the mixture particularly advantageously and consequently to achieve particularly advantageous operation of the burner, in one embodiment of the invention it is provided that the partial area extends completely around the circumferential direction of the channel around the flow direction, i.e. closed and thus over 360 degrees.

[0022] The aforementioned sub-region of the inner circumferential surface is also referred to as the first sub-region. When the term "sub-region" is used before and below, it refers, unless otherwise specified, to the first sub-region of the inner circumferential surface.

[0023] Another embodiment is characterized in that the surface structure has depressions and projections, wherein the depressions follow one another along the direction of airflow through the channel, and wherein the projections follow one another in the direction of airflow through the channel. It is provided that the depressions and the projections alternate in the direction of airflow through the channel, such that, viewed along the direction of flow, one of the depressions is arranged between two adjacent projections along the direction of flow, and, viewed along the direction of flow, one of the projections is arranged between two adjacent depressions along the direction of flow, and, in particular, one of the projections is arranged between two adjacent depressions along the direction of flow.The respective projection is raised inwards in the radial direction of the channel relative to the respective depression, the radial direction of which is perpendicular to the flow direction of the air flowing through the channel. It was found that a particularly advantageous turbulence of the air can be achieved by means of the depressions and projections.

[0024] To achieve particularly advantageous air turbulence and thus particularly advantageous mixture formation, a further embodiment of the invention provides that the respective depression and projection extend linearly in the circumferential direction of the channel. Specifically, it is provided that the respective depression and projection extend linearly in a plane perpendicular to the flow direction. Thus, for example, the respective depression or projection, viewed in the plane, has the shape of a circle whose center point lies, for example, on the flow direction. This allows for particularly advantageous air turbulence, and the surface structure can be produced particularly simply and therefore in a particularly time- and cost-effective manner.

[0025] In principle, it would be conceivable that the respective depression, also referred to as a groove or striation, and the respective projection run linearly in the direction of the air flowing through the channel.

[0026] In a further, particularly advantageous embodiment of the invention, each projection has a tip at which it terminates, particularly in the radial direction of the channel. This tip thus forms a further separation edge, thereby generating particularly advantageous air turbulence and, consequently, particularly advantageous mixture formation.

[0027] In order to achieve a particularly advantageous airflow and consequently a particularly advantageous operation of the burner, a further embodiment of the invention provides that the respective recess has a depth extending radially in the direction of the channel and thus perpendicular to the flow direction, which is at most or exactly 500 micrometers.

[0028] In a further particularly advantageous embodiment of the invention, the projections are arranged at a distance from one another that extends in the direction of airflow through the channel, and which here is at most or exactly 700 micrometers. This allows the air, or rather its flow, to be affected particularly advantageously, thereby enabling a particularly advantageous operation of the burner.

[0029] Another embodiment is characterized by the fact that, in the direction of airflow through the channel, a second section of the outer surface adjoins the first section, and this second section is free of a specifically manufactured surface structure. In particular, it is provided that the second section extends completely around the circumference of the channel. Thus, for example, the surface structure is only locally applied, which allows for a particularly advantageous mixture formation.

[0030] To enable particularly advantageous mixture formation, a further embodiment of the invention provides that the sub-section in the direction of airflow through the channel adjoins another sub-section of the outer surface, the latter being referred to as the third sub-section. This third sub-section is free of any specifically manufactured surface structure. This allows for a particularly advantageous airflow, thus enabling particularly advantageous mixture formation.

[0031] In order to form the mixture particularly advantageously, a further embodiment of the invention provides that the further sub-area extends completely around the channel in the circumferential direction and thus over 360 degrees.

[0032] A second aspect of the invention relates to a motor vehicle, also simply referred to as a vehicle, which has an internal combustion engine by means of which the motor vehicle can be propelled. The motor vehicle also has an exhaust system through which exhaust gas from the internal combustion engine flows, which includes at least one burner according to the first aspect of the invention. Advantages and advantageous embodiments of the first aspect of the invention are to be regarded as advantages and advantageous embodiments of the second aspect of the invention, and vice versa.

[0033] Further advantages, features, and details of the invention will become apparent from the following description of a preferred embodiment and from the drawing. The features and combinations of features mentioned above in the description, as well as those mentioned below in the figure description and / or shown in the figures alone, can be used not only in the combinations specified, but also in other combinations or individually, without departing from the scope of the invention.

[0034] The drawing shows in: Fig. 1 a schematic sectional view of a burner for an exhaust tract through which exhaust gas from an internal combustion engine of a motor vehicle flows; Fig. 2 a schematic perspective view of a component of the burner; Fig. 3 a schematic longitudinal sectional view of the component according to Fig. 2, Fig. 4 another schematic longitudinal section view of the component; and Fig. 5 a schematic and enlarged representation of a in Fig. 4. Area of ​​the component designated BE.

[0035] In the figures, identical or functionally equivalent elements are provided with the same reference symbols.

[0036] Fig. Figure 1 shows a schematic longitudinal section of a burner 10 for an exhaust tract through which exhaust gas from an internal combustion engine of a motor vehicle flows. The exhaust gas of the internal combustion engine is also referred to as engine exhaust. The motor vehicle, also simply referred to as a vehicle and preferably designed as a motor car, in particular as a passenger car or commercial vehicle, has a drive unit (not shown) by means of which the motor vehicle can be propelled. The drive unit comprises the internal combustion engine by means of which the motor vehicle can be propelled. The motor vehicle, in particular the drive unit, has the aforementioned exhaust tract, which is also referred to as the exhaust system. The motor vehicle is a land vehicle. The internal combustion engine is also referred to as an internal combustion engine, combustion engine, or motor. The internal combustion engine has an engine block, also referred to as the engine housing.Furthermore, the internal combustion engine has at least one or more cylinders, which are formed or delimited by the engine block, in particular directly. During firing operation of the internal combustion engine, combustion processes take place in the cylinders, resulting in the aforementioned engine exhaust. For this purpose, a fuel, in particular a liquid, is introduced into the respective cylinder during each operating cycle of the internal combustion engine, in particular by direct injection. The internal combustion engine can be designed as a diesel engine, so that the fuel is preferably diesel fuel.

[0037] The drive system includes, for example, an intake manifold through which fresh air flows, directing the fresh air flowing through the intake manifold to and into the cylinders. The intake manifold is also referred to as the intake tract. The fresh air mixes with the fuel to form an air-fuel mixture in the respective cylinder. This mixture, comprising the fresh air and the fuel, is ignited and thus combusted within the cylinder during the respective combustion cycle. Specifically, the air-fuel mixture is ignited and thus combusted by auto-ignition. The ignition and combustion of the air-fuel mixture results in the exhaust gas of the internal combustion engine. The drive system also includes the exhaust tract through which the exhaust gas from the cylinders flows.The internal combustion engine or drive unit also includes, for example, an exhaust gas turbocharger, which has a compressor located in the intake manifold and a turbine located in the exhaust manifold. The engine exhaust gas can flow out of the cylinders, into the exhaust manifold, and then flow through the exhaust manifold, in particular through an exhaust port of the exhaust manifold. The turbine can be driven by the exhaust gas of the internal combustion engine flowing through the exhaust manifold. The compressor can be driven by the turbine, in particular via a shaft of the exhaust gas turbocharger. By driving the compressor, the fresh air flowing through the intake manifold can be compressed by means of the compressor.The exhaust system contains, for example, several components, which can be configured as exhaust aftertreatment devices or elements, i.e., as exhaust aftertreatment components for treating the exhaust gas. In the direction of flow of the engine exhaust gas through the exhaust system, the components are arranged sequentially and thus connected in series. One of the components is, for example, an oxidation catalyst, in particular a diesel oxidation catalyst (DOC). Furthermore, the first component can be a nitrogen oxide storage catalyst (SOC), or the first component can include such a nitrogen oxide storage catalyst and / or an oxidation catalyst, in particular a diesel oxidation catalyst.The second component can be an SCR catalyst, or the second component can include such an SCR catalyst. A third component can be a particulate filter, or include such a particulate filter. The particulate filter is, for example, a diesel particulate filter (DPF). A fourth component can be, for example, a second SCR catalyst, or include such a second SCR catalyst. Alternatively or additionally, the fourth component can include an ammonia slip catalyst (ASC), or be designed as such. In the direction of flow of the engine exhaust gas through the exhaust tract, the second component is located downstream of the first component, the third component downstream of the second component, and the fourth component downstream of the third component.

[0038] The drive unit can include a metering device by means of which a reducing agent, particularly a liquid, can be introduced, particularly injected, into the exhaust system, especially the exhaust duct, and thereby, for example, into the engine exhaust flowing through the exhaust system, particularly the exhaust duct. The reducing agent is preferably an aqueous urea solution that can provide ammonia, which can react with any nitrogen oxides contained in the exhaust gas to form water and nitrogen during selective catalytic reduction. This selective catalytic reduction can be catalytically effected and / or supported by the respective SCR catalyst.In the direction of flow of the engine exhaust gas flowing through the exhaust tract, the metering point is arranged, for example, upstream of the second component and, for example, downstream of the first component, with the second component being arranged downstream of the first component. For example, the exhaust tract has a mixing chamber in which the reducing agent introduced into the exhaust gas at the metering point can advantageously be mixed with the engine exhaust gas, with the mixing chamber being arranged, for example, upstream of the second component and, for example, downstream of the first component.

[0039] The exhaust system, and thus the drive unit and the motor vehicle, also includes the burner 10, by means of which at least one of the components, in particular, for example, the second component and / or the third component and / or the fourth component, can be heated and / or kept warm quickly and efficiently, wherein the at least one component is arranged in the exhaust system, in particular downstream of the burner 10. The burner 10 can combust a mixture, also referred to as a burner mixture, in particular by forming a flame, resulting in exhaust gas from the burner 10, also referred to as burner exhaust gas. The burner 10 can provide the burner exhaust gas. For example, the burner exhaust gas or the flame can be introduced into the exhaust system, i.e., for example, into the exhaust duct, at an inlet point. This means that, so to speak, the burner 10 is arranged at the inlet point.For example, the inlet is located upstream of the second component, upstream of the third component, upstream of the fourth component, and downstream of the first component. In other words, for example, the burner 10 is located upstream of the second component, downstream of the first component, and, for example, upstream of the third component and upstream of the fourth component. Alternatively, it is conceivable that the burner 10, or rather the inlet, is located upstream of the first component and, in particular, downstream of the turbine. Thus, for example, the turbine is located upstream of the first component. The aforementioned burner mixture to be combusted in or by means of the burner 10 comprises air, which is also referred to as burner air, and a preferably liquid fuel. For example, in the case described in... Fig. In the embodiment shown in Figure 1, the aforementioned fuel is used as the fuel. Alternatively or additionally, at least a portion of the burner air supplied to the burner 10 and used to form the mixture can originate, for example, from the intake manifold.

[0040] As from Fig. As can be seen from Figure 1, the burner 10 has a combustion chamber 12 in which the burner mixture, comprising the burner air supplied to the burner 10 and the preferably liquid fuel supplied to the burner 10, is to be ignited and thereby combusted, i.e., ignited and thereby combusted during operation of the burner 10. The combustion chamber 12 is delimited, in particular directly, by a chamber element 14, which in this case is designed as a solid body, and in particular by an inner circumferential surface 16 of the chamber element 14. The burner 10 has an ignition device 18, in particular designed as a spark plug, glow plug, or glow pin, and in particular electrically operated, by means of which the mixture can be ignited.By means of the ignition device 18, in particular by using electrical energy with which the ignition device 18 can be supplied or is supplied, at least one ignition spark can be generated at at least or exactly one ignition point Z, by means of which the mixture in the combustion chamber 12 can be ignited and subsequently burned, in particular by providing the burner exhaust gas and / or by providing the aforementioned flame. It is evident that the ignition point Z is arranged in the combustion chamber 12.The burner exhaust gas, or more precisely the flame, can be used to quickly and efficiently heat and / or maintain the engine exhaust flowing through the exhaust tract or exhaust channel. This allows the heated and / or maintained engine exhaust gas, which flows through at least the second component and preferably also the third and fourth components, to be used to quickly and efficiently heat and / or maintain the second component. The chamber element 14 has at least one, or in this case several, flow openings 20 through which the burner exhaust gas from the combustion chamber 12 can flow. Thus, the burner exhaust gas can be discharged from the combustion chamber 12 via the flow openings 20 and introduced into the exhaust tract, i.e., the exhaust channel.

[0041] At the in Fig. In the embodiment shown in Figure 1, the burner 10 has a first channel 22 with a first swirl chamber 24, which is also referred to as the inner swirl chamber. A first portion of the burner air can flow through the first channel 22 and thus the first swirl chamber 24. A first swirl flow of the first portion of the burner air can be effected by means of the first swirl chamber 24. When air is mentioned below, this refers to the burner air unless otherwise specified. The feature that the first swirl flow of the first portion of the air can be effected by means of the first swirl chamber 24 means, in particular, that the first portion of the air flows in a swirl pattern through at least a first sub-section of the swirl chamber 25 and / or flows out of the swirl chamber 24 in a swirl pattern and / or flows in a swirl pattern into and thus into the combustion chamber 12.The first channel 22 and, in particular, the first swirl chamber 24 have a first outlet opening 26, which can be flowed through by the first part of the air in a first direction of passage of the outlet opening 26 and thus in a first direction of flow that coincides with the first direction of passage, or through which the first part of the air flows during the operation of the burner 10.

[0042] The burner 10 also has an injection element 28 by means of which the fuel can be introduced, at least indirectly, and in particular directly, into the first channel 22 and thus, in this case, into the first swirl chamber 24, and in particular injected. The first channel 22, and thus, in this case, the first swirl chamber 24, can therefore be permeated by both the first portion of air and the fuel injected from the injection element 28, so that the first outlet opening 26 can be permeated by both the first portion of air and the fuel from the injection element 28. The first portion of air and, in this case, the fuel can flow through the first channel 22, and thus the first swirl chamber 24 and the first outlet opening 26, in the first flow direction, which is illustrated by an arrow 30.The injection element 28 has, for example, at least or exactly one outlet opening, also referred to as an injection opening, or at least or exactly three outlet openings, also referred to as injection openings, wherein the respective outlet opening is permeable to the fuel supplied to the injection element 28. The injection element 28 can inject the fuel from itself via its respective outlet opening and, in particular, introduce it, at least indirectly, and especially directly, into the first channel 22 and thus into the first swirl chamber 24, forming a jet of fuel. In particular, the injection element 28 can introduce the fuel into the first channel 22 bypassing the combustion chamber 12.

[0043] At the in Fig. In the embodiment shown in Figure 1, the burner 10 further comprises a second channel 32 with a second swirl chamber 34. The second swirl chamber 34 is an outer swirl chamber which surrounds at least a length of the first channel 22 and thus the first swirl chamber 24, and in particular completely, the first outlet opening 26, in a circumferential direction around the first flow direction. The first flow direction, through which the first portion of air and fuel can flow into the first outlet opening 26, runs in the axial direction of the first swirl chamber 24 or coincides with the axial direction of the first swirl chamber 24. The circumferential direction of the inner swirl chamber (swirl chamber 24) runs around the axial direction of the inner swirl chamber (swirl chamber 24).The second channel 32, and thus the outer, second swirl chamber 34, whose axial direction coincides with that of the first swirl chamber 24, is designed to allow a second portion of the burner air to flow through it in a second direction and is configured to generate a second swirl flow of this second portion of air. The second flow direction and the first flow direction point in the same direction, so the second flow direction is also illustrated by arrow 30. The feature that the outer, second swirl chamber 34 is configured to generate the second swirl flow means that the second portion of air flows through the swirl chamber 34 in a swirl pattern and / or flows out of the swirl chamber 34 in a swirl pattern and / or flows into and thus into the combustion chamber 12 in a swirl pattern.In particular, it is provided that the second part of the burner air flows in a swirling fashion through at least a second sub-area of ​​the second swirl chamber 34 and / or flows out of the second swirl chamber 34 in a swirling fashion and / or flows in a swirling fashion into and thus into the combustion chamber 12.

[0044] The second channel 32, and thus the outer, second swirl chamber 34, whose radial direction is perpendicular to the axial direction of the swirl chamber 34, has, in particular, a second outlet opening 36 through which the second part of the air flowing through the channel 32, and thus the swirl chamber 34, can flow in the second flow direction, and whose second direction of passage coincides with the first flow direction. The second outlet opening 36 is permeable in the second direction of passage, and thus in the second flow direction, by the second part of the air flowing through the second channel 32, and thus the second swirl chamber 34.The second flow direction, and thus the second passage direction, coincides with the axial direction of the second swirl chamber 34 and thus with the axial direction of the second swirl chamber 24, whose radial direction is perpendicular to the axial direction of the first swirl chamber 24 and, in this case, coincides with the radial direction of the second swirl chamber 34. It can be seen that the outlet opening 36 is arranged downstream of the second outlet opening 26 in the flow direction of the respective portion of the air and thus also in the flow direction of the fuel, so that the second outlet opening 36 can be permeated by the second portion of the air, the first portion of the air, and the fuel.In the direction of airflow through channels 22 and 32 and thus through swirl chambers 24 and 34, the second outlet opening 36 is arranged downstream of the first outlet opening 28 and is arranged or connected in series with the first outlet opening 26, so that the second outlet opening 36 can be accessed by the second part of the air, the first part of the air and also by the fuel from channel 22 or swirl chamber 24.

[0045] The burner 10 also has a shut-off device 37. The shut-off device 37 is located in the combustion chamber 12 and comprises a drive shaft 37.1, a pivoting lever 37.2, and a shut-off element 37.3. The shut-off element 37.3 can be moved in front of the first outlet opening 26 and the second outlet opening 36 by means of a pivoting movement, thus closing them off from the combustion chamber 12. This protects the outlet openings 26, 36 and the swirl chambers 24, 34 from exhaust gas from the exhaust tract and thus from exhaust gas contamination. During operation of the burner 10, the shut-off element 37.3 is pivoted away from the outlet openings 26, 36 via the pivoting lever 37.2 by actuating the drive shaft 37.1, allowing air and fuel to enter the combustion chamber 12.

[0046] From a synthesis of Fig. Figures 1 to 3 show that the first channel 22 is directly bounded by a solid component 38 of the burner 10. In this case, the first channel 22 is directly bounded by an inner circumferential surface 40 of the component 38. Specifically, the inner circumferential surface 40 directly forms or bounds a flow cross-section of the first channel 22, the flow cross-section of which, in the first flow direction (arrow 30), is permeable to the first portion of the air and, in this case, also to the fuel. In this case, the first channel 22 is designed as a nozzle, at least over a length L of the first channel 22, such that the flow cross-section tapers in the first flow direction. The first channel 22 has an end E facing the combustion chamber 12, at which the first channel 22 terminates in the first flow direction.The first outlet opening 26 is located at end E, so that the first channel 22, and in this case also the first swirl chamber 24, terminate at end E and thus at the first outlet opening 26 when viewed in the first flow direction. Therefore, the first portion of the air, and in this case also the fuel, can flow out of the first channel 22 at and via end E and subsequently be fed to the combustion chamber 12 via the second outlet opening 36.

[0047] In the embodiment shown in the figures, the component 38 is formed in one piece, that is, from a single piece. This is particularly well suited to... Fig. 2 and Fig. It can be seen that the component 38 forms and thus has a first swirl-generating device 41 of the first swirl chamber 24. By means of the first swirl-generating device 41, the first swirl-shaped flow of the first part of the air can be caused. A second swirl-generating device 42 is particularly well suited to Fig. 4 can be seen forming the swirl generation device 42 of the second swirl chamber 34.

[0048] In order to achieve a particularly advantageous mixture formation, also referred to as mixture formation, and consequently a particularly advantageous operation of the burner 10, the solid component 38 has several slots S at the end E of the first channel 22 facing the combustion chamber 12. In this case, the number of slots S is greater than one, specifically six. The multiple slots S are evenly distributed along the circumferential direction of the first channel 22, which runs around the first flow direction and thus around the axial direction of the first swirl chamber 24. It can be seen that each slot S is continuous in the first flow direction, as illustrated by arrow 30.In a first direction opposite to the first flow direction, illustrated by arrow 43, the respective slot S is bounded by a respective first wall region W1 of the component 38. The first flow direction (arrow 30) and the first direction (arrow 43) run, for example, along a common first straight line that runs axially along the channel 22, in this case the swirl chamber 24 and the outlet opening 26. In the circumferential direction of the first channel 22 around the first flow direction, the respective slot S is bounded on both sides directly by a respective second wall region W2 of the component 38. Along a second direction (arrow 43) that runs perpendicular to the first flow direction (arrow 30) and perpendicular to the first direction, the respective slot S is continuous. The second direction (arrow 43) runs along a second straight line that is perpendicular to the first straight line.Thus, for example, the second direction and the circumferential direction of the first channel 22 lie in a plane that is perpendicular to the first direction and perpendicular to the first line, with the second line, for example, lying in the plane. For example, the respective slot S has a length along the first flow direction of the air flowing through the first channel 22, which is greater than zero and at most 3 millimeters. In particular, the length can be exactly 3 millimeters.

[0049] In order to achieve an advantageous, turbulent flow of the first part of the air, it is preferably provided that at least a partial area of ​​the mantle surface 40 is provided with a specifically manufactured surface structure.

[0050] Looks especially good Fig. Figure 3 shows that the first channel 22 and the component 38, viewed in the first flow direction (arrow 30), terminate at a separation edge K of the component 38, whose separation edge K directly borders the outlet opening 26. The air and fuel flowing through the first channel 22 can be discharged from the first channel 22 and fed to the combustion chamber 12 via the outlet opening 26. The slots S allow for a particularly long separation edge K, also referred to as the separation edge length, which enables the inner circumferential surface 40 to be wetted, or wetted, by the fuel being introduced into the first channel 22 at least indirectly, and in particular directly, by means of the fuel being introduced into the first channel 22 by means of the introduction element 28. This results in particularly advantageous, and especially particularly fine, droplets. This, in turn, allows for a particularly advantageous formation of the mixture.In the embodiment shown in the figures, the separation edge K is formed by a region B of the component 38, the wall thickness of which tapers in the first flow direction up to the separation edge K. This allows the separation edge K to be designed as a particularly sharp or pointed edge, which advantageously enables the formation of droplets from the fuel.

[0051] Out of Fig. 4 and Fig. Figure 5 shows that at least a partial area TB1 of the inner circumferential surface 40 is provided with a specifically produced surface structure 44. For example, the surface structure 44 is specifically produced by, in particular, mechanical, machining of the circumferential surface 40, wherein the mechanical machining is preferably turning or includes turning. Fig. 4 It is particularly evident that the sub-area TB1 extends completely around the channel 22 in the circumferential direction and thus over 360 degrees.

[0052] Fig. Figure 5 shows a schematic and enlarged representation of a Fig. 4. Area of ​​the component designated BE. From Fig. Figure 5 shows that the surface structure 44 also has depressions 46 and projections 48, also referred to as grooves or ridges, with the depressions 46 and projections 48 alternating in the direction of flow (arrow 30). In the present section, viewed in a plane of section in which the direction of flow (arrow 30) runs, the projections 48 and the depressions 46 form a sawtooth structure. Each depression 46 and each projection 48 run linearly in the circumferential direction of the channel 22 and thus, in particular, in a second plane that is perpendicular to the aforementioned plane of section and perpendicular to the first direction of flow (arrow 30). Therefore, each projection 48 and each depression 46 is radially oriented.In other words, the projection of each projection 48 and each depression 46 onto a projection plane perpendicular to the first flow direction (arrow 30) is circular, i.e., it has the shape of a circle whose center lies, for example, on the first flow direction (arrow 30). It is also evident that each projection 48 has a tip SP at which it terminates radially inwards along the channel 22. These tips S thus form additional separation edges beyond the separation edge K, which are perpendicular to a conical angle. For example, each projection 48 has, in particular, two successive flanks in the flow direction (arrow 30). Each flank forms an angle α with the aforementioned projection plane.Arrows 50 illustrate that the inner circumferential surface 40 does not necessarily have to be provided with the surface structure 44 only locally, but in comparison to the one in . Fig. 4 and Fig. The illustration shown in 5 can, for example, be the one in Fig. 4 and Fig. The surface structure 44 shown in section 5 is continued along the arrows 50, that is, in the respective directions illustrated by the arrows 50. Fig. Figure 5, where t represents the respective distance between two adjacent projections 48 along the flow direction illustrated by arrow 30, where, for example, the distance t is greater than zero and at most 700 micrometers. In particular, for example, the respective distance t is exactly 700 micrometers. Fig.In section 5, s denotes the respective depth of each recess 46 extending radially in the direction of the channel 22, where, for example, the respective depth s of each recess 46 corresponds to the respective height of each projection 48 extending radially in the direction of the channel 22. For example, the respective depth s is greater than zero and at most 500 micrometers, and in particular, the respective depth s can be exactly 500 micrometers. Since, for example, the recesses 46 and the projections 48 can be produced by turning, the respective recess 46 is, for example, designed as a respective turning groove, also simply referred to as a groove. The surface structure 44 allows for particularly advantageous turbulence of the air flowing through the first channel 22, which enables the formation of particularly advantageous droplets from the fuel and the particularly advantageous mixing of the droplets with the air.This allows the mixture to be formed in a particularly advantageous way. Reference symbol list 10 burners 12 Combustion chamber 14 chamber element 16 inner circumferential surface 18 Ignition device 20 Flow opening 22 first channel 24 first swirl chamber 26 first outlet 28 Insertion element 30 Arrow 32 second channel 34 second swirl chamber 36 second outlet 37 Locking device 37.1 Drive shaft 37.2 Swivel lever 37.3 Locking element 38 Component 40 inner circumferential surface 41 first swirl-generating device 42 second swirl generating device 43 Arrow 44 Surface structure 46 In-depth study 48 lead 50 Arrow Area B BE area E End K tear-off edge L Length range s depth S slot SP Peak t distance TB1 Sub-area W1 first wall area W2 second wall area Z Ignition point α angle QUOTES INCLUDED IN THE DESCRIPTION

[0000] This list of documents cited by the applicant was automatically generated and is included solely for the reader's convenience. The list is not part of the German patent or utility model application. The DPMA accepts no liability for any errors or omissions. Cited patent literature

[0000] DE 10 2021 001 580 A1

[0002] EP 1 391 653 A2

[0002]

Claims

[1] 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 fuel is to be ignited and thereby burned; - a component (38) which directly delimits at least one first channel (22) through which at least a portion of the air can flow, and through which the air flowing through the first channel (22) can be supplied to the combustion chamber (12); and - a feed element (28) by means of which the fuel can be introduced into the channel (22); characterized by , that the first channel (22) is directly bounded by an inner circumferential surface (40) of the component (38), wherein at least a partial area (TB1) of the surface (40) is provided with a specifically manufactured surface structure (44). [2] Burner (10) according to claim 1, characterized by, that the sub-area (TB1) extends completely around the perimeter of the channel (22). [3] Burner (10) according to claim 1 or 2, characterized by , that the surface structure (44) has depressions (46) and projections (48), wherein the depressions (46) and the projections (48) alternate in the direction of flow (30) of the air flowing through the channel (22). [4] Burner (10) according to claim 3, characterized by , that the respective depression (46) and the respective projection (48) each run in a linear fashion in the circumferential direction of the first channel (22). [5] Burner (10) according to claim 3 or 4, characterized by , that the respective lead (48) has a respective peak (SP) at which the respective lead (48) ends. [6] Burner (10) according to one of claims 3 to 5, characterized by , that each depression (46) has a depth (s) which is at most or exactly 500 micrometers. [7] Burner (10) according to any one of claims 3 to 6, characterized by , that the projections (48) are arranged at a distance (t) from each other in the direction of flow (30) of the air flowing through the first channel (22), which is at most or exactly 700 micrometers. [8] Burner (10) according to any one of the preceding claims, characterized by , that in the direction of flow (30) of the air flowing through the first channel (22) a second sub-area of ​​the mantle surface (40) adjoins the sub-area (TB1), the second sub-area of ​​which is free from a deliberately produced surface structure. [9] Burner (10) according to any one of the preceding claims, characterized by , that the sub-area (TB1) in the direction of flow (30) of the air flowing through the first channel (22) connects to a further sub-area of ​​the mantle surface (40), the further sub-area of ​​which is free from a specifically produced surface structure. [10] Motor vehicle, with an internal combustion engine by means of which the motor vehicle can be driven, and with an exhaust tract through which exhaust gas of the internal combustion engine flows, which has at least one burner (10) according to one of the preceding claims.

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