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 component (38) has at least one slot (S) at one end (E) of the channel (22) facing the combustion chamber (12).

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 is a burner for an exhaust tract through which exhaust gas of an internal combustion engine of a motor vehicle flows, as is known, with a combustion chamber in which a mixture comprising air and a fuel is to be ignited and thereby burned.

[0003] Furthermore, EP 1 391 653 A2 discloses a pre-filmer for a fuel injection arrangement.

[0004] 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.

[0005] This problem is solved by a burner with the features of claim 1 and by a motor vehicle with the features of claim 9. Advantageous embodiments with expedient further developments of the invention are specified in the remaining claims.

[0006] 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.

[0007] The burner has a combustion chamber, also referred to as the main combustion chamber, in which a mixture comprising air and a preferably liquid fuel can be ignited and thereby combusted. 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, also referred to as the burner 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 hot burner exhaust gas mixes with the engine exhaust gas. Consequently, the burner exhaust gas, especially the burner exhaust gas mixed with the engine exhaust gas, can flow through the component, thereby heating it up.In particular, it is conceivable that burner exhaust gas can escape from the combustion chamber and flow 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.

[0008] The burner has at least one channel through which at least a portion of the air flows. When air is mentioned before and after, unless otherwise specified, this refers to the air that forms the mixture, also known as burner air. The aforementioned channel is also referred to as the first channel. The air flowing through the channel, that is, the air forming the aforementioned portion, can be supplied to the combustion chamber via the channel. Thus, the channel is arranged upstream of the combustion chamber in the direction of air flowing through it (burner air), and the combustion chamber is arranged downstream of the channel in the direction of air flowing through it.During burner operation, the air flows through the duct in the aforementioned direction. During operation, that is, while the burner is firing, the burner provides the exhaust gas, thus combusting the mixture in the combustion chamber. This aforementioned flow direction is also referred to as the primary flow direction. Whenever the flow direction is mentioned before and below, unless otherwise specified, it refers to the primary flow direction in which the burner air flows through the duct during burner operation. In particular, the duct has at least one or exactly one outlet opening through which the air flowing through the duct can be discharged and supplied to the combustion chamber, specifically, introduced into the combustion chamber.The aforementioned outlet is also referred to as the first outlet. Whenever the outlet is mentioned before or below, this refers, unless otherwise specified, to the first outlet.

[0009] The burner includes a component designed as a solid body, which may, for example, be provided in addition to the aforementioned chamber element. It is conceivable that the chamber element and the component are designed separately and connected to each other, at least indirectly, and in particular directly. Furthermore, it is conceivable that the component and the chamber element are formed integrally, that is, from a single piece. This means, in particular, that the component and the chamber element are not designed separately and connected to each other, but rather, for example, that the chamber element and the component are formed by a single, integrally manufactured body, thus forming a monoblock.The component, in particular an inner circumferential surface of the component, directly delimits the channel, so that the burner air, as it passes through the channel, directly contacts the component, in particular the inner circumferential surface of the component. When the inner circumferential surface is mentioned before and below, this refers, unless otherwise specified, to the inner circumferential surface of the component. The inner circumferential surface of the component is a surface of the component, which, for example, may be concave.

[0010] The burner also has a feed element by means of which the fuel can be introduced, in particular directly, into the channel, especially by injection. In other words, the feed element is permeable to the preferably liquid fuel. The feed element can introduce the fuel flowing through it into the channel at least indirectly, in particular directly, especially by injection. For this purpose, for example, the feed element injects the fuel flowing through it from itself.

[0011] For example, the burner can have an ignition device, particularly an electrically operated one, by means of which the mixture, especially in the combustion chamber, is 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 by which the ignition device can be supplied or is supplied, so that the mixture, especially in the combustion chamber, can be ignited and subsequently combusted, 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.

[0012] 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 after, it refers, unless otherwise specified, to the first portion of air. The duct is designed, for example, to create a swirling flow of the first portion of air, i.e., the air flowing through the duct. This swirling flow of the air, i.e., the air flowing through the duct, is also called the first swirling flow. For example, the duct may have a swirl chamber, also called the first swirl chamber, by means of which the first swirling flow of the air flowing through the duct can be created. The first swirl chamber is, for example, an internal swirl chamber, which will be explained in more detail below.The first channel, and thus, for example, the first swirl chamber, is arranged upstream of the combustion chamber in the direction of airflow through the first channel. The first swirl chamber has, for example, a first outlet opening through which the air flowing through the first channel can be discharged and supplied to 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.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, i.e., at least a first sub-area of ​​the first swirl chamber flows through in a swirl pattern, and / or the first part of the air only exhibits its first swirl flow at least in a first flow area 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 pattern and / or flows into the combustion chamber in a swirling pattern, so that it is most preferably provided that the first part of the air 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.

[0013] The burner also includes the injection element by means of which the fuel can be introduced, particularly at an injection point. For example, the injection element is an injection element by means of which the fuel can be introduced, particularly at the injection point. The injection point is, for example, located in the channel or upstream of the channel in the direction of air flow. In particular, the injection point can, for example, be located in the first swirl chamber. The injection element has, for example, at least or exactly one inlet 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 flowing through the injection element can be discharged from the injection element via the respective outlet opening and introduced, at least indirectly, and in particular directly, into the channel, especially injected.

[0014] For example, the burner can have a second channel through which a second part of the air forming the mixture (burner air) can flow.

[0015] For example, the second channel is designed to create a second swirling 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 swirling flow of the second portion of air (burner air) can be created. If, for example, the first swirl chamber is the aforementioned inner swirl chamber, then the second swirl chamber is, for example, an outer swirl chamber. The outer swirl chamber surrounds, for example, at least a portion of the inner swirl chamber, and preferably also the first outlet opening, in the circumferential direction of the inner swirl chamber, in particular completely. The circumferential direction of the inner swirl chamber is around the aforementioned first flow direction, in which the air, or the first portion of the air, can or does flow through the first channel.The second channel, and thus, for example, the second swirl chamber, is permeable to the second portion of air in a second flow direction, preferably with the first and second flow directions coinciding. In particular, the flow directions point in the same direction. Most specifically, 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, for example, downstream of the second swirl chamber. When the flow direction is mentioned before and below, unless otherwise specified, this refers 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 it, i.e., in the axial direction of the first swirl chamber and thus of the first outlet. The second swirl chamber, whose axial direction coincides with that of the first swirl chamber, is permeable to the second portion of air, particularly 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. This 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.

[0016] For example, the second channel, in particular the second swirl chamber, has in particular exactly 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, for example, is arranged 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 introduced into the combustion chamber.

[0017] 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.

[0018] Since, for example, the fuel can be introduced into the first channel at least indirectly, and in particular directly, by means of the introduction element, the first channel, and thus, for example, the first outlet opening, can be permeated by the first portion of air and the fuel. Thus, for example, the first portion of air and the fuel can be discharged from the first channel via the first outlet opening. Since, for example, the second outlet opening is located downstream of the first outlet opening, the second outlet opening can be permeated by the first portion of air flowing through the first outlet opening, by the fuel flowing through the first outlet opening, and by the second portion of air, so that, for example, the second portion of air and the fuel, as well as the first portion of air, can be supplied to the combustion chamber via the second outlet opening, and in particular, introduced into the combustion chamber.

[0019] 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 or channel. 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, for example, also the fuel, can flow along the second flow direction, especially in the second flow direction, through the second outlet opening and thus enter the combustion chamber via the second outlet opening, wherein, for example, the second flow direction runs parallel to the first flow direction or coincides with the first flow direction.Furthermore, it is preferably provided that the second flow direction runs in the axial direction of the second swirl chamber and thus, in particular, of the second outlet opening, and therefore coincides 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, and 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 axial direction of each swirl chamber is perpendicular to its radial direction, 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, i.e., 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 terminates at the second outlet opening, especially at its end, in the flow direction of the second portion of air flowing through the second outlet opening.

[0020] For example, in order to effect 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.

[0021] To achieve a particularly advantageous operation of the burner, the invention provides that the component has at least one or exactly one slot at one end of the channel facing the combustion chamber, where the channel terminates at said end when viewed in the direction of flow. At said end of the channel, the air flowing through the channel can be discharged from the channel. This means that the air flowing through the channel can escape from the channel at or over the end of the channel, or does escape during burner operation.Therefore, the end of the channel is also referred to as an outlet or nozzle outlet, whereby the cross-section of the channel through which the air flows does not necessarily have to taper in the direction of flow, but can, so that, for example, the channel can be designed as a nozzle, particularly in the classical sense. Compared to conventional solutions, the slot allows for a significant extension of the tear-off edge of the component.The component ends at the aforementioned separation edge, particularly when viewed in the direction of flow. This means that, for example, at the separation edge located at the end of the channel, the air flowing through the channel can detach from the component, or detach during the aforementioned operation of the burner. This allows for a particularly advantageous airflow pattern, enabling, for example, a particularly advantageous mixing of the air with the fuel. Consequently, a particularly advantageous mixture preparation, also known as mixture conditioning, can be achieved, resulting in particularly advantageous burner operation.In particular, the following can be provided: Since the fuel can be introduced, at least indirectly, and especially directly, into the channel by means of the injection element, the aforementioned inner circumferential surface of the component can, for example, be wetted with the fuel by introducing the fuel into the channel. Thus, for example, the injection element can apply the fuel to the inner circumferential surface of the component.The fuel thus forms, for example, a film, also known as a fuel film, on the inner circumferential surface of the component. This film is carried through the channel in the direction of airflow, and in particular along the inner circumferential surface, such that during this transport, the film flows directly along and directly contacts this surface. The air flowing through the channel thus propels the fuel film to the aforementioned separation edge.At the separation edge, the film—that is, the flow of the film along the inner circumferential surface, or the flow of the fuel forming the film along the inner circumferential surface—tears away from the component, thereby forming droplets, for example, from the fuel. The slot allows for a particularly advantageous droplet characteristic, also known as droplet distribution, in particular such that the droplets are advantageously small and / or uniformly distributed. Consequently, the droplets, and thus the fuel, can be mixed particularly effectively with the burner air, enabling a highly efficient mixture preparation. Since the aforementioned fuel film can be formed or created by means of this component, it is also referred to as a prefilmer.When the term "prefilmer" is used before and below, it refers to the component unless otherwise specified.

[0022] By means of the injection element, the fuel can, for example, be injected into the channel, forming a jet also referred to as a fuel jet, and introduced directly into the channel. The jet is, for example, conical and thus shaped as a cone or truncated cone. The jet, in particular the cone or truncated cone, has a cone angle and / or a diameter.

[0023] 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 to effectively and efficiently heat the component, particularly during a cold start. This is especially advantageous when the internal combustion engine is a diesel engine and / or when the vehicle is heavy, for example, a commercial vehicle. The burner allows the component to be maintained within an advantageous temperature range and / or brought into a temperature range where it can effectively treat the exhaust gas. The burner enables the component to be heated and / or kept warm without producing significant emissions.The injection element can, for example, eject the fuel from itself and thereby introduce it, at least indirectly, and especially directly, into the channel, particularly by injection, thus allowing the fuel to be applied to the inner circumferential surface of the component. Subsequently, the fuel can form the aforementioned fuel film on the inner circumferential surface of the component. The air flowing through the channel and the fuel flowing through the channel and along the inner circumferential surface can detach from the component, particularly from the separation edge, forming the aforementioned droplets. Typically, the droplet statistics, also known as droplet statistics, are not very specific, meaning that the burner and its operation are sensitive to environmental parameters.The design of a flow geometry, particularly of the air and / or fuel, and thus, for example, the design of the cone angle and / or diameter, is usually based on the required swirl and the burner's output, and therefore on a desired mass flow rate, also known as the air mass flow. Unfortunately, it has been found that the surface area of ​​the component resulting from this design is very small within a target performance range, and consequently, severe interruptions due to insufficient or inadequate mixture formation can occur repeatedly, especially in cold and / or high-altitude conditions. The invention resolves this conflict between the aforementioned flow design and the insufficient active surface area by providing the component with at least one slot at the end of the channel. In conventional solutions, the separation edge follows a circular path.In other words, conventional solutions provide for the separation edge to coincide with a circle, thus having the shape of a circle, with the circle, for example, being located at one end of a cone. In contrast to such a circular separation edge, the separation edge of the component of the burner according to the invention is interrupted by the slot, also referred to as a cut or notch, thereby creating a greater separation edge length compared to conventional solutions. In other words, compared to conventional solutions, an increase in the active separation edge length can be achieved, thereby enabling higher energy for droplet dispersion and mixture formation.

[0024] In order to achieve a particularly advantageous mixture formation and thus a particularly advantageous operation of the burner, one embodiment of the invention provides that the slot is continuous in the direction of flow of the air flowing through the channel, so that the slot is unlimited when viewed in the direction of flow of the air flowing through the channel and thus opens into or onto an environment of the component.

[0025] It has proven particularly advantageous if the slot is bounded in a first direction opposite to the flow direction by a wall region of the component, also referred to as the first wall region, in particular directly, wherein the slot is continuous and thus unlimited in a second direction perpendicular to the flow direction and perpendicular to the first direction. The second direction runs in a plane that is perpendicular to the flow direction and perpendicular to the first direction. In the circumferential direction of the channel around the flow direction, the slot is bounded on both sides by respective further wall regions of the component, in particular directly. Thus, a particularly advantageous flow and, consequently, a particularly advantageous mixture formation and advantageous burner operation can be achieved.

[0026] Another embodiment is characterized by the slot having a length greater than zero, extending in the direction of airflow through the channel, and measuring at most 3 millimeters. Thus, compared to conventional solutions, it is possible, for example, to achieve with each slot of the component that a multiple, in particular twice, of the slot's length extending in the direction of airflow is added as the additional length of the separation edge. This allows for the creation of particularly advantageous fuel droplets by means of the component, resulting in a particularly advantageous mixture formation and thus a particularly advantageous burner operation.

[0027] In a further, particularly advantageous embodiment of the invention, the component has at least or exactly two slots at the end of the channel, and thus several slots in total, namely the aforementioned slot as the first slot and at least or exactly one or more second slots. This allows for a particularly long separation edge, which in turn enables the particularly advantageous formation of droplets from the fuel. Consequently, a particularly advantageous mixture formation and, as a result, a particularly advantageous operation of the burner can be achieved.

[0028] It has proven particularly advantageous if the slots of the component, especially all of them, located at the end of the channel, are evenly distributed around the circumference of the channel, running around the direction of flow. This allows for a particularly favorable statistical distribution and / or characteristic of the droplets formed by the fuel, thus enabling a particularly advantageous mixture formation.

[0029] Another embodiment is characterized in that the channel is directly bounded by the inner circumferential surface of the component, wherein at least a portion of the inner circumferential surface is provided with a specifically manufactured surface structure, also referred to as surface texturing. Most preferably, the surface structure is a microstructure, which is microscopically fine and only detectable with optical aids. This results in a surface imperfection on the inner circumferential surface, which allows for particularly advantageous turbulence of the air flowing through the channel. Consequently, droplets can be formed from the fuel with particular advantage, leading to particularly advantageous mixture formation and, consequently, particularly advantageous burner operation.In particular, a particularly advantageous starting behavior of the burner can be achieved, so that the burner can be reliably started even when the vehicle is at a high altitude above sea level and / or when cold temperatures prevail in the vehicle's environment.

[0030] To achieve particularly advantageous burner operation, a further embodiment of the invention provides that the channel and the component terminate at the aforementioned trailing edge of the component, with the trailing edge directly defining the channel's outlet opening. The air flowing through the channel, and, for example, the fuel flowing through the channel, can be discharged from the channel via the outlet opening and fed to the combustion chamber, in particular, introduced directly into the combustion chamber. The trailing edge is formed by a region of the component whose solid section has a wall thickness that tapers in the direction of airflow through the outlet opening up to the trailing edge.This allows the cutting edge to be designed as a particularly sharp and / or pointed edge, which enables the fuel to form especially advantageous droplets. As a result, particularly favorable mixture formation and thus particularly advantageous burner operation can be ensured.

[0031] A second aspect of the invention relates to a motor vehicle, also referred to simply as a vehicle and preferably designed as a motor car, 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.

[0032] 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.

[0033] 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, also known as a pre-filmer; and Fig. 3 a schematic sectional view of the component according to Fig. 2.

[0034] In the figures, identical or functionally equivalent elements are provided with the same reference symbols.

[0035] 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.

[0036] 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.

[0037] 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.

[0038] 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.

[0039] 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.

[0040] 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.

[0041] 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 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 two 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 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.

[0042] 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 the axial direction 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 second swirl chamber 34 in a swirl pattern and / or flows out of the second 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.

[0043] The second channel 32, and thus the outer, second swirl chamber 34, whose radial direction is perpendicular to the axial direction of the second swirl chamber 34, has, in particular, a second outlet opening 36 through which the second part of the air flowing through the second channel 32, and thus the second swirl chamber 34, can flow in the second flow direction, and whose second direction of passage coincides with the second 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 therefore with the axial direction of the first 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 second outlet opening 36 is arranged downstream of the first 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 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.

[0044] 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.

[0045] 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 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 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 channel 22 is designed as a nozzle, at least over a length L of the channel 22, such that the flow cross-section tapers in the first flow direction. The channel 22 has an end E facing the combustion chamber 12, at which the channel 22 terminates in the first flow direction.The outlet opening 26 is located at end E, so that the channel 22, and in this case also the swirl chamber 24, terminate at end E and thus at the outlet opening 26 when viewed in the first flow direction. Therefore, the first part of the air, and in this case also the fuel, can flow out of the channel 22 at and via end E and subsequently be fed into the combustion chamber 12.

[0046] 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 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. 1 recognizable that the swirl generation device 42 forms the second swirl chamber 34.

[0047] 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 channel 22 facing the combustion chamber 12. In this case, the number of slots is greater than one, specifically six. The multiple slots S are evenly distributed around the circumferential direction of the channel 22, which runs around the first flow direction and thus around the axial direction of the swirl chamber 24. It can be seen that each slot S is continuous in the first flow direction, illustrated by arrow 30. In a first direction opposite to the first flow direction, illustrated by arrow 43, each slot S is bounded by a 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, which runs in the axial direction of the channel 22, in this case the swirl chamber 24 and the outflow opening 26. In the circumferential direction of the channel 22, which runs around the first flow direction, the respective slot S is directly bounded on both sides by a further wall region W2 of the component 38. Along a second direction that runs perpendicular to the first flow direction and perpendicular to the first direction, the respective slot S is continuous. The second direction runs along a second straight line, which is perpendicular to the first straight line. Thus, for example, the second direction and the circumferential direction of the channel 22 run in a plane that is perpendicular to the first direction and perpendicular to the first straight line, with the second straight line, for example, lying in the plane.For example, each slot S has a length extending along the first flow direction of the air flowing through channel 22, which is greater than zero and at most 3 millimeters. In particular, the length can be exactly 3 millimeters.

[0048] 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.

[0049] Looks especially good Fig.Figure 3 shows that, viewed in the first flow direction (arrow 30), the channel 22 and the component 38 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 channel 22 can be discharged from the 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 fact that the fuel is introduced into the channel 22 at least indirectly, and in particular directly, 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.

[0050] 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. 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 38 Component 40 inner circumferential surface 41 first swirl-generating device 42 second swirl generating device 43 Arrow Area B E End K tear-off edge S slot W1 first wall area W2 second wall area Z Ignition point 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

[0003]

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 component (38) has at least one slot (S) at one end (E) of the first channel (22) facing the combustion chamber (12). [2] Burner (10) according to claim 1, characterized by , that the slot (S) is continuous in the direction of flow (30) of the air flowing through the first channel (22). [3] Burner (10) according to claim 2, characterized by, that the slot (S) is limited in a first direction (43) opposite to the flow direction (30) by a wall area (W1) of the component (38) and is continuous along a second direction perpendicular to the flow direction (30) and perpendicular to the first direction (43). [4] Burner (10) according to any one of the preceding claims, characterized by , that the slot (S) has a length extending in the direction of flow (30) of the air flowing through the first channel (22) which is at most three millimeters. [5] Burner (10) according to any one of the preceding claims, characterized by , that the component (38) at the end (E) of the first channel (22) has at least or exactly two slots (S), namely the slot (S) as the first slot and a second slot (S). [6] Burner (10) according to claim 5, characterized by , that the slots (S) are evenly distributed in the circumferential direction of the first channel (22). [7] Burner (10) according to any one of the preceding claims, characterized by , that the first channel (22) is directly bounded by an inner circumferential surface (40) of the component (38), wherein at least a part of the surface (40) is provided with a specifically manufactured surface structure. [8] Burner (10) according to any one of the preceding claims, characterized by, that the first channel (22) and the component (38) terminate at a separation edge (K) of the component (38), the separation edge (K) of which directly limits an outlet opening (26) of the first channel (22), through the first outlet opening (26) of which the air flowing through the first channel (22) can be discharged from the first channel (22) and supplied to the combustion chamber (12), wherein the separation edge (K) is formed by a region (B) of the component (38), the region (B) of which has a wall thickness that tapers in the direction of flow (30) of the air flowing through the first outlet opening (26) up to the separation edge (K). [9] 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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