DE102022002121B4 - Burner for a motor vehicle and motor vehicle with at least one such burner - Google Patents

Abstract

Burner (12) for an exhaust tract (10) through which exhaust gas from an internal combustion engine of a motor vehicle can flow, with:- a combustion chamber (16) in which a mixture comprising air and a fuel is to be ignited and thereby burned,- an inner swirl chamber (20) through which a first part of the air can flow, which has a first swirl generating device (55) by means of which a swirl-shaped flow (50) of the first part of the air can be brought about, and a first outflow opening (22) through which the first part of the air flowing through the inner swirl chamber (20) can flow, via which the first part of the air can be discharged from the inner swirl chamber (20),- an introduction element (24) through which the fuel can flow, by means of which the fuel can be introduced into the inner swirl chamber (20), the first outflow opening (22) of which can also be flowed through by the fuel discharged from the introduction element (24), and- a region of at least one length of the inner swirl chamber (20) an outer swirl chamber (30) which surrounds the inner swirl chamber (20) in the circumferential direction and through which a second part of the air can flow, which outer swirl chamber has a second swirl generating device (57) by means of which a swirl-shaped flow (50) of the second part of the air can be brought about, and a second outflow opening (34) through which the second part of the air flowing through the outer swirl chamber (30), the fuel flowing through the first outflow opening (22) and the first part of the air flowing through the inner swirl chamber (30) and the first outflow opening (22) can flow, via which the parts of the air and the fuel can be introduced into the combustion chamber (16), wherein at least one surface (26, 38, 64, 65) which at least partially directly delimits the inner swirl chamber (20) and/or the outer swirl chamber (30) is formed by a coating (66) with which a base body (68) of the burner carrying the coating (66) (12) and the coating (66) is catalytically active.

Description

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

Motor vehicles with internal combustion engines and exhaust systems, also known as exhaust tracts, are known from the general state of the art and in particular from series vehicle construction. The exhaust tract is capable of being flowed through by exhaust gas from the respective internal combustion engine, also known as an internal combustion engine. In some operating states or operating situations of the respective internal combustion engine, a high temperature of the exhaust gas may be desirable, for example in order to be able to quickly heat up and/or keep warm an exhaust gas aftertreatment device arranged in the exhaust tract, although in these operating states or operating situations the actual temperature of the exhaust gas is not high enough.

The DE 37 29 861 C2 A method for operating a soot filter device for a diesel engine is known. Furthermore, the EN 11 2012 001 594 T5 an article comprising an engine or propulsion component and a coating applied to the engine or propulsion component. Furthermore, the EN 11 2012 001 599 T5 A method for applying a coating to an engine, exhaust system or powerplant component is known.

The DE 102 11 590 A1 discloses an atomizer nozzle for exhaust gas purification systems. The atomizer nozzle has an inner swirl chamber through which a first part of the air can flow, by means of which a swirling flow of the first part of the air can be brought about, and a first outflow opening through which the first part of the air flowing through the inner swirl chamber can flow, via which the first part of the air can be discharged from the inner swirl chamber. The atomizer nozzle has an outer swirl chamber surrounding the inner swirl chamber in a length region of the inner swirl chamber in the circumferential direction of the inner swirl chamber and through which a second part of the air can be brought about. The atomizer nozzle has a second outflow opening through which the second part of the air flowing through the outer swirl chamber and the first part of the air flowing through the inner swirl chamber and the first outflow opening can flow through.

The AT 406 706 B discloses a burner with a combustion chamber in which a mixture comprising air and a fuel is to be ignited and thereby burned. The burner has an inner swirl chamber through which a first part of the air can flow, by means of which a swirling flow of the first part of the air can be brought about, and a first outflow opening through which the first part of the air flowing through the inner swirl chamber can flow, via which the first part of the air can be discharged from the inner swirl chamber. Furthermore, the burner has an introduction element through which a fuel can flow, by means of which the fuel can be introduced into the inner swirl chamber and whose first outflow opening can also be flowed through by the fuel discharged from the introduction element. The burner has an outer swirl chamber in a length region of the inner swirl chamber in the circumferential direction of the inner swirl chamber, through which a second part of the air can be flowed through, by means of which a swirling flow of the second part of the air can be brought about. The burner has a second outflow opening through which the second part of the air flows through the outer swirl chamber, the fuel flows through the first outflow opening and the first part of the air flows through the inner swirl chamber and the first outflow opening. The parts of the air and the fuel can be introduced into the combustion chamber via the second outflow opening.

The DE 100 55 613 A1 shows a device for carrying out a method for supplying thermal energy and/or fuel into a gas stream, in one embodiment as a two-tube burner. The heat of the exhaust gas can be conducted from the area of an outer chamber to the area of an inner chamber via components which enlarge a surface of an outer wall of an inner tube element. A catalytic coating can be applied in the area of the components,

The DE 44 17 769 A1 shows a premix burner. The premix burner has the shape of a straight channel. A fuel is injected into the head of this channel using several injectors. Downstream of a mixing tube forming the first part of the premix burner, there is an ignition zone as a continuation of the channel. An inward-facing surface of a wall in the area of the ignition zone can be supplemented by a catalytic coating.

The object of the present invention is to provide a burner for an exhaust system of 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.

This object is achieved by a burner having the features of patent claim 1 and by a motor vehicle having the features of patent claim 8. Advantageous embodiments with expedient further developments of the invention are specified in the remaining claims.

A first aspect of the invention relates to a burner for an exhaust tract through which exhaust gas from an internal combustion engine of a motor vehicle, also referred to as an internal combustion engine or internal combustion engine, can flow. This means that the motor vehicle, which can preferably be designed as a motor vehicle and very preferably as a passenger car, has the internal combustion engine and the exhaust tract in its fully manufactured state and can be driven by means of the internal combustion engine. During fired 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. The exhaust gas can flow out of the respective combustion chamber and flow into the exhaust tract and subsequently flow through the exhaust tract, which is also referred to as the exhaust system. At least one component such as an exhaust aftertreatment element for aftertreating the exhaust gas can be arranged in the exhaust tract. The exhaust gas aftertreatment element is, for example, a catalyst, in particular an SCR catalyst, wherein, for example, a selective catalytic reduction (SCR) can be catalytically supported and/or effected by means of the SCR catalyst, so that, for example, the SCR catalyst is catalytically active for the SCR. During selective catalytic reduction, any nitrogen oxides contained in the exhaust gas are at least partially removed from the exhaust gas by the nitrogen oxides reacting with ammonia to form nitrogen and water during selective catalytic reduction. The ammonia is provided, for example, by a reducing agent, in particular a liquid one. Furthermore, the exhaust gas aftertreatment element can be a particle filter, in particular a diesel particle filter, or comprise a particle filter, in particular a diesel particle filter, wherein particles contained in the exhaust gas, in particular soot particles, can be filtered out of the exhaust gas by means of the particle filter.

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 burned. The combustion of the mixture, which takes place in particular in the combustion chamber, produces a burner exhaust gas from the burner, in particular in the combustion chamber. The burner exhaust gas can, for example, flow out of the combustion chamber and into the exhaust tract, i.e., for example, into an exhaust duct of the exhaust tract through which the exhaust gas of the internal combustion engine can flow, in particular at an inlet point which is arranged upstream of the aforementioned component, for example in the flow direction of the exhaust gas of the internal combustion engine flowing through the exhaust tract or the exhaust duct. For example, the burner exhaust gas mixes with the exhaust gas of the internal combustion engine. This is particularly advantageous during a cold start or when the internal combustion engine is not yet fully at operating temperature, since the burner exhaust gas, in particular the burner exhaust gas mixed with the exhaust gas of the internal combustion engine, can then flow through the component, for example, whereby the component can be heated up, i.e. warmed up. In particular, it is conceivable that the burner exhaust gas can flow out of the burner chamber and into the exhaust tract or into the aforementioned exhaust duct and is thereby mixed with the exhaust gas of the internal combustion engine flowing through the exhaust tract, also referred to as engine exhaust gas, and/or with a gas flowing through the exhaust tract, whereby the exhaust gas of the internal combustion engine or the gas is heated. In other words, this can achieve a particularly high temperature of the exhaust gas of the internal combustion engine or the gas, also referred to as the exhaust gas temperature. In particular, the gas can be air or combustion air, for example, which flows through the exhaust tract or the exhaust duct, for example, in particular while the internal combustion engine is not being operated with fire, so that the internal combustion engine does not provide any exhaust gas, in which case the gas, in particular the combustion air, is then conveyed through the exhaust tract by the internal combustion engine. The high exhaust gas temperature can heat the component, since the exhaust gas flows through the component with the burner exhaust gas or the gas flows through the component with the burner exhaust gas. Thus, for example, the burner exhaust gas from the combustion chamber is introduced into the exhaust tract or into the exhaust duct at the aforementioned inlet point and thus into the exhaust gas or gas flowing through the exhaust tract. For example, an ignition device, in particular an electrically operated one, is provided, whereby the burner can comprise the ignition device. In particular, it is conceivable that the ignition device at least partially eg arranged in the combustion chamber. By means of the ignition device, in particular in the combustion chamber and/or using electrical energy, at least one ignition spark for igniting the mixture can be provided, i.e. generated, so that the mixture in the combustion chamber can be ignited in particular by means of the ignition spark. The ignition device is, for example, a glow plug or a spark plug.

The burner has an inner swirl chamber through which a first part of the air forming the mixture in the combustion chamber can flow and which causes a swirling flow of the first part of the air, which is thus preferably arranged upstream of the combustion chamber in the flow direction of the first part of the air flowing through the inner swirl chamber. When air is mentioned below, this is to be understood, unless otherwise stated, as the air forming the mixture in the combustion chamber, i.e. the air from which the mixture is formed, in particular together with the fuel. The air is, for example, ambient air. The inner swirl chamber has, in particular precisely, a first outflow opening through which the first part of the air flowing through the inner swirl chamber can flow, via which the first part of the air flowing through the first outflow opening can be discharged from the inner swirl chamber and, for example, introduced into the combustion chamber. Thus, in particular, the combustion chamber is arranged downstream of the inner swirl chamber in the flow direction of the first part of the air flowing through the inner swirl chamber. The feature that the inner swirl chamber causes or can cause a swirl-like flow of the first part of the air flowing through the inner swirl chamber is to be understood in particular as meaning that the first part of the air flows through the inner swirl chamber in a swirl-like manner, thus flows through at least a first partial area of the inner swirl chamber in a swirl-like manner, and/or the first part of the air only has its swirl-like flow at least in a first flow area arranged downstream of the inner swirl chamber and outside the inner swirl chamber, which is arranged, for example, in the combustion chamber. In particular, it is conceivable that the first part of the air flows out of the inner swirl chamber in a swirl-like manner via the first outflow opening and/or flows into the combustion chamber in a swirl-like manner, so that it is very preferably provided that the first part of the air has its swirl-like flow at least in the combustion chamber. In particular, it is conceivable that the first part of the air already has its swirl-like flow in the inner swirl chamber, namely at least in the aforementioned at least one first partial area of the inner swirl chamber.

The burner also has an introduction element, in particular an injection element, which has at least or exactly one outlet opening through which the preferably liquid fuel can flow. In particular, it is conceivable that the introduction element has several, in particular more than two, outlet openings through which the preferably liquid fuel can flow. In particular, it is conceivable that the introduction element has at least or exactly three outlet openings through which the fuel can flow. By means of the introduction element, the fuel can be introduced, in particular injected, into the inner swirl chamber, in particular directly, so that the preferably liquid fuel that has exited, in particular sprayed out, from the introduction element via the at least one outlet opening and is thereby introduced, in particular injected, into the inner swirl chamber, in particular directly, can also flow through the first outlet opening. This means in particular that the first part of the air and the fuel flow through the first outlet opening along a common, first flow direction and can thereby flow out of the inner swirl chamber.

Furthermore, the burner comprises an outer swirl chamber which surrounds at least a length region of the inner swirl chamber and preferably also the first outflow opening in the circumferential direction of the inner swirl chamber, in particular completely circumferentially. The circumferential direction of the inner swirl chamber runs, for example, in the aforementioned first flow direction, which runs, for example, in the axial direction of the inner swirl chamber and thus the first outflow opening, and thus coincides with the axial direction of the inner swirl chamber and thus the outflow opening. It is preferably provided that the inner swirl chamber ends in the flow direction of the first part flowing through the first outflow opening and thus in the flow direction of the fuel flowing through the first outflow opening, thus in the axial direction of the inner swirl chamber and thus the first outflow opening at the first outflow opening or at the end thereof. The outer swirl chamber, the axial direction of which coincides with the axial direction of the inner swirl chamber, can be flowed through by a second part of the air and is designed to cause a swirling flow of the second part of the air. This is to be understood in particular as meaning that the second part of the air flows in a swirl-like manner in the outer swirl chamber, thus flowing through at least a second partial area of the outer swirl chamber in a swirl-like manner, and/or the second part of the air has a downstream direction in the flow direction of the second part of the air flowing through the outer swirl chamber. the second flow region arranged in the outer swirl chamber, which coincides for example with the aforementioned first flow region, has its swirling flow, wherein the second flow region can be arranged for example outside the outer swirl chamber and for example inside the combustion chamber. It is also conceivable that the aforementioned first flow region is arranged outside the outer swirl chamber. In other words, it is conceivable that the second part of the air flows out of the outer swirl chamber in a swirling shape and/or flows into the combustion chamber in a swirling shape, so that it is preferably provided that the second part of the air has its swirling flow at least in the combustion chamber.

The outer swirl chamber has, in particular precisely, a second outflow opening through which the second part of the air flowing through the outer swirl chamber, the fuel flowing through the first outflow opening and the first part of the air flowing through the inner swirl chamber and the first outflow opening can flow and which is arranged, for example, in the flow direction of the parts of the air and the fuel downstream of the first outflow opening, via which the second part of the air can be discharged from the outer swirl chamber and the parts of the air and the fuel can be introduced into the combustion chamber.

Thus, for example, the feature that the outer swirl chamber causes or can cause a swirl-like flow of the second part of the air flowing through the outer swirl chamber is to be understood in particular as meaning that the second part of the air flows through the outer swirl chamber in a swirl-like manner, thus flows through at least a second partial area of the outer swirl chamber in a swirl-like manner, and/or the second part of the air only has its swirl-like flow at least in a second flow area arranged downstream of the outer swirl chamber and outside the outer swirl chamber, which is arranged, for example, in the combustion chamber. In particular, it is conceivable that the second part of the air flows out of the outer swirl chamber in a swirl-like manner via the second outflow opening and/or flows into the combustion chamber in a swirl-like manner, so that it is very preferably provided that the second part of the air has its swirl-like flow at least in the combustion chamber. In particular, it is conceivable that the second part of the air already has its swirl-like flow in the outer three-chamber, namely at least in the aforementioned at least one second partial area of the outer swirl chamber.

In particular, it can thus be provided that the combustion chamber is arranged downstream of the inner swirl chamber and/or downstream of the outer swirl chamber in the flow direction of the respective part of the air flowing through the respective swirl chamber. In particular, the parts of the air and the fuel can flow through the second outflow opening along a second flow direction and thus flow into the combustion chamber via the second outflow 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 outer swirl chamber, thus coinciding with the axial direction of the outer swirl chamber, so that it is very preferably provided that the axial direction of the inner swirl chamber corresponds to the axial direction of the outer swirl chamber or vice versa. In other words, it is preferably provided that the axial direction of the inner swirl chamber coincides with the axial direction of the outer swirl chamber or vice versa. The respective axial direction of the respective swirl chamber runs perpendicular to the respective radial direction of the respective swirl chamber, wherein the radial direction of the inner swirl chamber preferably coincides with the radial direction of the outer swirl chamber or vice versa. Since, for example, the second outflow opening is arranged along the respective flow direction, i.e. in the flow direction of the respective part of the air and in the flow direction of the fuel downstream of the first outflow opening, and since the outer swirl chamber preferably surrounds the first outflow opening, the first outflow opening is arranged in the outer swirl chamber, for example. In particular, it is conceivable that the outer swirl chamber ends at the second outflow opening, in particular at the end thereof, in particular in the flow direction of the second part of the air flowing through the second outflow opening.

In order to generate the respective swirl-shaped flow, the respective swirl chamber can have at least one or more swirl generators, by means of which the respective swirl-shaped flow can be generated or is generated. In particular, the respective swirl generator is arranged in the respective swirl chamber. In particular, the respective swirl generator can be, for example, a guide vane, by means of which, for example, the respective part, i.e. the respective air forming the respective part, is deflected at least or exactly once, in particular by at least or exactly 70°, in particular by at least substantially 90°, i.e. for example by 70° to 90°. In particular, the respective swirl-shaped flow is to be understood as a flow which is swirl-shaped, i.e. at least in the Essentially extends in a helical or spiral shape around the respective axial direction of the respective swirl chamber or the respective outflow opening. In particular, the respective axial direction of the respective outflow opening runs perpendicular to a plane in which the respective outflow opening runs. In this case, for example, the respective axial direction of the respective outflow opening coincides with the respective axial direction of the respective swirl chamber. The respective outflow opening is also referred to, for example, as the respective nozzle, the cross-section through which the respective part of the air can flow does not necessarily have to taper along the respective flow direction, but can taper. Thus, for example, the second outflow opening is also referred to as the outer nozzle or second nozzle, whereby the first outflow opening is also referred to as the inner nozzle or first nozzle.

By causing the respective swirling flow, the air can be mixed particularly advantageously with the preferably liquid fuel, particularly over a small mixing path, particularly in the combustion chamber, so that a particularly advantageous mixture preparation is realized, i.e. the mixture can be formed particularly advantageously. In particular, the fuel can initially be mixed particularly well with the first part of the air, particularly in the inner swirl chamber, particularly due to the swirling flow of the first part of the air, particularly in the inner swirl chamber. In addition, the fuel and, for example, the first part of the air already mixed with the fuel can be mixed particularly advantageously with the second part of the air, particularly in the outer swirl chamber and/or in the combustion chamber, since the second part of the air also has an advantageous swirling flow. Overall, due to the swirling flows, the parts of the air and the fuel can be mixed particularly advantageously, so that an advantageous mixture preparation can be achieved. The swirling flow of the first part of the air and the swirling flow of the second part of the air have the same direction of the respective swirl, in particular the two flows coincide.

The inner swirl chamber has a first, inner swirl generating device, by means of which the first, swirl-shaped flow of the first part of the air can be brought about.

Thus, for example, the inner swirl generating device has the aforementioned at least one swirl generator of the inner swirl chamber. Furthermore, the outer swirl chamber has an outer, second swirl generating device, by means of which the second, swirl-shaped flow of the second part of the air can be brought about. Thus, for example, the outer swirl generating device has the aforementioned at least one swirl generator of the outer swirl chamber. For example, the swirl generating devices form a swirl generating device or the swirl generating devices are components of a swirl generating device of the burner. In particular, it is conceivable that the two swirl generating devices are formed integrally with one another, i.e. are formed by a one-piece component, so that the two swirl generating devices are formed, for example, from a single piece, i.e. by a single piece. This means that the swirl generating devices are not formed as components that are formed separately from one another and connected to one another. Furthermore, it is conceivable that the swirl generating devices are formed separately from one another and in particular are components that are connected to one another. For example, the first swirl generating device has at least one or more first swirl generating elements, such as preferably first guide vanes, wherein the air or the first part of the air can advantageously be guided or deflected or redirected by means of the first swirl generating element or by means of the first swirl generating elements in such a way that the swirl-shaped flow of the first part of the air can be brought about, i.e. is brought about. Thus, for example, the first swirl generating element is the aforementioned swirl generator of the inner swirl chamber. Alternatively or additionally, it is conceivable that the second swirl generating device comprises at least one or more second swirl generating elements, such as preferably second guide vanes, wherein the air or the second part of the air can be guided or deflected or redirected by means of the second swirl generating element or by means of the second swirl generating elements in such a way that the second swirl-shaped flow of the second part of the air can be brought about, i.e. is brought about. In particular, it is conceivable that the second swirl generating element is the aforementioned swirl generator of the outer swirl chamber. Preferably, it is provided that the swirl generating elements of the respective swirl generating device are arranged in succession and/or spaced apart from one another in the circumferential direction of the respective swirl chamber, in particular around the respective axial direction of the respective swirl chamber. For example, the at least one first partial area of the inner swirl chamber is arranged downstream of the first swirl generating device in the flow direction of the first part of the air flowing through the inner swirl chamber. It is also conceivable that the at least a second partial region of the outer swirl chamber is arranged downstream of the second swirl generating device in the flow direction of the second part of the air flowing through the outer swirl chamber.

In particular, it is conceivable that the respective swirl generating elements of the respective swirl chamber form respective swirl channels through which the respective part of the air can flow, i.e., in particular, directly delimit them, so that the respective swirl-shaped flow can be effected or is effected by means of the swirl channels. In particular, it is possible for the swirl channels to be arranged one after the other in the circumferential direction of the respective swirl chamber and in particular at a distance from one another.

In order to be able to realize particularly advantageous operation of the burner, in particular over a long service life of the burner, a surface of the burner, for example designed as an inner peripheral surface, in particular concave or convex, is formed by a coating with which a base body carrying the coating and in particular designed separately from the coating is provided, wherein the surface and thus the coating directly delimit the inner swirl chamber and/or the outer swirl chamber at least partially, in particular at least predominantly and thus at least more than half or completely. In this case, it is particularly provided that the coating and the base body are made of different materials, in particular such that the coating is made of a first material and the base body is made of a second material that is different from the first material. The feature that the surface and thus the coating directly delimit the inner swirl chamber and/or the outer swirl chamber at least partially is to be understood with regard to the respective swirl chamber as meaning that the respective air flowing through the respective swirl chamber flows directly onto the surface, thus directly touching it. Because the surface is formed by the coating with which the base body is provided, the coating can, for example, be adjusted or selected, particularly with regard to the material from which the coating is formed, in such a way that excessive deposits on the surface can be avoided and/or deposits on a surface can be counteracted. Because the base body is provided with the coating, the base body can be formed from a different, less expensive material than the coating, so that a particularly advantageous operation of the burner can be achieved in a particularly cost-effective and/or lightweight manner. The invention is based in particular on the following findings and considerations. When the internal combustion engine is running, i.e. when the internal combustion engine is in fired mode, and when the burner is deactivated, i.e. when the burner does not provide the burner exhaust gas, i.e. when no burner exhaust gas is formed in the combustion chamber, the exhaust gas of the internal combustion engine, also known as engine exhaust gas, in particular from the exhaust tract, can penetrate into the combustion chamber and, in particular via the combustion chamber, possibly as far as the first swirl generating device and/or the second swirl generating device. If no appropriate countermeasures are taken, this can result in excessive deposits on, in particular in, the combustion chamber and possibly in the respective swirl chamber and/or on the respective swirl generating device. The deposits are also known as deposits. The deposit can have an unfavorable influence, in particular on the flow of the respective part of the air, such as the swirl-shaped flow, in particular in such a way that the flow cross sections of the burner, in particular the swirl chambers and especially the swirl generation device, through which the air can flow, can be narrowed in an undesirable manner. The coating provided according to the invention is now a countermeasure by means of which excessive deposits in the burner can be avoided and/or excessive deposits can be counteracted. For this purpose, for example, all or at least cross-section-critical areas of the burner are directly delimited by the coating and thus the surface. In particular, all or at least cross-section-critical areas or components that come or can come into direct contact with the engine exhaust gas are formed or directly delimited by the coating. As a result, flow-favorable conditions in the burner, in particular in the respective swirl chamber, can be ensured even over a long service life of the burner, so that advantageous mixture preparation and, as a result, particularly efficient operation can be achieved.

In order to particularly advantageously avoid excessive deposits in the burner and/or to be able to counteract excessive deposits particularly advantageously, it is provided in an advantageous embodiment of the invention that the coating is catalytically active.

In this respect, it has proven to be particularly advantageous if the coating is designed to burn off any deposited Soot, and thus carbon is catalytically active. This embodiment is based in particular on the knowledge that the aforementioned coating can be formed in particular by soot from the exhaust gas of the internal combustion engine and can thus be formed as so-called coking. The coating can therefore prevent excessive coking of flow-conducting areas or components of the burner. As a result, undesirable, excessive cross-sectional tapering in the burner can be avoided, so that an excessive drop in performance and poor starting behavior of the burner can be avoided.

A further embodiment is characterized in that the coating contains at least cerium oxide, which is also referred to simply as cerium. This makes it possible, for example, to realize a particularly advantageous catalytic effect of the coating, in particular for oxidation of soot deposited on the coating, so that excessive deposits can be advantageously prevented or excessive deposits can be advantageously counteracted.

It has been shown to be particularly advantageous if the coating has at least one coating component that can activate oxygen. This coating component can in particular be the aforementioned cerium oxide, as a result of which, for example, deposits on the coating can be advantageously removed, in particular burned off.

In a further, particularly advantageous embodiment of the invention, the coating comprises at least one precious metal, which can, for example, reduce the oxidation temperature of soot. Soot, for example, can thus be particularly advantageously removed from the coating, so that excessive deposits can be avoided or removed.

In order to be able to guarantee particularly advantageous and particularly efficient operation of the burner even over a long service life, a further embodiment of the invention provides that at least one swirl channel of the inner swirl chamber and/or outer swirl chamber, through which the air, i.e. the respective part of the air, can flow to create the swirling flow, is directly delimited at least partially, in particular at least predominantly or completely, by the coating. This embodiment is based on the knowledge that the swirl channel in particular can have a particularly small or narrow flow cross-section, in particular the smallest or narrowest flow cross-section, of the respective swirl chamber, in particular of the burner. An undesirable, excessive narrowing of the flow cross-section would lead to an undesirable drop in performance and/or to poor starting behavior of the burner, which can now be advantageously avoided.

In order to be able to achieve a particularly advantageous mixture preparation and thus a particularly advantageous operation of the burner, it is provided in a further embodiment of the invention that the first part of the air can be fed to the inner swirl chamber in the radial direction of the inner swirl chamber from the outside to the inside. In other words, the first part of the air does not flow axially, but radially into the first swirl chamber.

Alternatively or additionally, it is provided that the second part of the air can be fed to the outer swirl chamber in the radial direction of the outer swirl chamber from the outside to the inside. In other words, the second part of the air does not flow into the outer swirl chamber in the axial direction of the outer swirl chamber but in the radial direction of the outer swirl chamber, which allows a particularly advantageous mixture preparation to be achieved.

A second aspect of the invention relates to a motor vehicle, preferably designed as a motor vehicle, in particular as a passenger car, which has an internal combustion engine by means of which the motor vehicle can be driven. The motor vehicle also has an exhaust tract through which exhaust gas from the internal combustion engine can flow, which has 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.

Further advantages, features and details of the invention emerge 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 the features and combinations of features mentioned below in the description of the figures and/or shown alone in the figures can be used not only in the combination specified in each case, but also in other combinations or on their own, without departing from the scope of the invention.

• 1 ausschnittsweise eine schematische Schnittansicht eines Abgastrakts einer Verbrennungskraftmaschine eines Kraftfahrzeugs, mit einem Brenner;
• 2 ausschnittsweise eine weitere schematische Schnittansicht des Abgastrakts;
• 3 ausschnittsweise eine weitere schematische Schnittansicht des Abgastrakts;
• 4 eine schematische Längsschnittansicht des Brenners;
• 5 eine schematische Perspektivansicht einer Drallerzeugungsvorrichtung des Brenners;
• 6 eine schematische und perspektivische Längsschnittansicht der Drallerzeugungsvorrichtung;
• 7 eine weitere schematische Längsschnittansicht des Brenners;
• 8 ausschnittsweise eine schematische Schnittansicht des Brenners.

The drawing shows in:

• 1 a detail of a schematic sectional view of an exhaust tract of an internal combustion engine of a motor vehicle, with a burner;
• 2 a further schematic sectional view of the exhaust tract;
• 3 a further schematic sectional view of the exhaust tract;
• 4 a schematic longitudinal sectional view of the burner;
• 5 a schematic perspective view of a swirl generating device of the burner;
• 6 a schematic and perspective longitudinal sectional view of the swirl generating device;
• 7 another schematic longitudinal sectional view of the burner;
• 8th A schematic sectional view of the burner.

In the figures, identical or functionally identical elements are provided with identical reference symbols.

1 shows a detail in a schematic sectional view of an exhaust tract 10, also referred to as an exhaust system, of a motor vehicle preferably designed as a motor vehicle, in particular as a passenger car. The motor vehicle has a drive device, not shown in detail in the figures, by means of which the motor vehicle can be driven. The motor vehicle also has the exhaust tract 10. The motor vehicle is a land vehicle. The drive device has an internal combustion engine, also referred to as an internal combustion engine or combustion machine, which has an engine block, also referred to as an 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 fired operation of the internal combustion engine, respective combustion processes take place in the cylinders, resulting in exhaust gas from the internal combustion engine. For this purpose, a fuel, in particular a liquid fuel, is introduced into the respective cylinder, in particular directly injected, within a respective working cycle of the internal combustion engine. The internal combustion engine can be designed as a diesel engine, so that the fuel is preferably a diesel fuel. A tank referred to as a fuel tank is also provided, in which the fuel can be received or is accommodated. For example, a respective injector is assigned to the respective cylinder, by means of which the fuel can be introduced into the respective cylinder, in particular directly injected. For example, the fuel is pumped from the tank to a high-pressure pump by means of a low-pressure pump, by means of which the fuel is pumped to the injectors or to a fuel distribution element common to the injectors and also referred to as a rail or common rail. The injectors can be supplied with the fuel from the fuel distribution element common to the injectors by means of the fuel distribution element and can introduce the fuel from the fuel distribution element into the respective cylinder, in particular directly inject it.

The drive device includes, for example, an intake tract through which fresh air can flow, by means of which the fresh air flowing through the exhaust tract is guided to and into the cylinders. The fresh air forms a fuel-air mixture with the fuel, which includes the fresh air and the fuel and is ignited and thus burned in the respective cylinder within the respective working cycle. In particular, the fuel-air mixture is ignited by self-ignition. The ignition and combustion of the fuel-air mixture results in the exhaust gas of the internal combustion engine, whose exhaust gas is also referred to as machine exhaust gas or engine exhaust gas.

The drive device has, for example, the exhaust tract 10 through which the exhaust gas from the cylinder of the internal combustion engine can flow. The internal combustion engine also comprises, for example, an exhaust turbocharger, which has a compressor arranged in the intake tract and a turbine arranged in the exhaust tract. The exhaust gas can first flow out of the cylinders into the turbine, flow from the turbine into the exhaust tract 10 and then flow through the exhaust tract 10. The turbine can be driven by the exhaust gas flowing through the exhaust tract 10. The compressor can be driven by the turbine, in particular via a shaft of the exhaust turbocharger. By driving the compressor, the fresh air or ambient air flowing through the intake tract is compressed by means of the compressor. In the exhaust tract 10, for example, several components are arranged which are designed as respective exhaust gas aftertreatment devices or exhaust gas aftertreatment elements, i.e. as exhaust gas aftertreatment components for aftertreating the exhaust gas. In the flow direction of the exhaust gas of the internal combustion engine flowing through the exhaust tract 10, the components are arranged one after the other and are thus connected in series or in series with one another. A first of the components 11 is, for example, an oxidation catalyst, in particular a diesel oxidation catalyst (DOC). Furthermore, the first component 11 can be a nitrogen oxide storage catalyst (NSK) or the first component 11 can be such a nitrogen oxide storage catalyst A second of the components can be an SCR catalyst, which is also simply referred to as SCR. A third of the components can be a particle filter, in particular a diesel particle filter (DPF), wherein the diesel particle filter (DPF) can also act as the first component 11. A fourth of the components can be, for example, a second SCR catalyst and/or an ammonia blocking catalyst (ASC). In other words, the fourth component can, for example, have a second SCR catalyst and/or an ammonia blocking catalyst.

The motor vehicle has a structure designed, for example, as a self-supporting body, which forms or delimits an interior of the motor vehicle, also referred to as a passenger cell or safety cell or passenger compartment. While the motor vehicle is being driven, people can be in the interior. For example, the structure forms or delimits an engine compartment in which the internal combustion engine is arranged. The exhaust gas turbocharger is also arranged in the engine compartment, for example. The structure also has a floor, also referred to as the main floor, by which the interior is at least partially, in particular at least predominantly or completely, delimited downwards in the vertical direction of the vehicle. For example, the first component 11, the second component and the third component are arranged in the engine compartment, so that, for example, the first component, the second component and the third component form a so-called hot end or are part of a so-called hot end. In particular, the hot end can be flanged directly to the turbine. The fourth component is arranged, for example, outside the engine compartment and below the floor in the vertical direction of the vehicle, so that the fourth component forms a so-called cold end or is part of a so-called cold end.

The exhaust tract 10 can comprise at least one metering device, by means of which a reducing agent, in particular a liquid one, can be introduced into the exhaust tract 10 at an introduction point and, for example, into the exhaust gas flowing through the exhaust tract 10. The reducing agent is preferably an aqueous urea solution, which can provide ammonia, which can react with any nitrogen oxides contained in the exhaust gas to form water and nitrogen during a selective catalytic reduction. The selective catalytic reduction can be catalytically effected and/or supported by the SCR catalyst. In the flow direction of the exhaust gas flowing through the exhaust tract 10, the introduction point is arranged, for example, upstream of the second component and downstream of the first component 11, with the second component being arranged downstream of the first component. It is also conceivable that the introduction point is arranged upstream of the first component 11. For example, the fourth component is arranged downstream of the third component, with the third component being arranged downstream of the second component. For example, the exhaust tract has a mixing chamber in which the reducing agent introduced into the exhaust gas at the introduction point can advantageously be mixed with the exhaust gas, wherein, for example, the mixing chamber can be arranged upstream of the second component and, for example, downstream of the first component.

The exhaust system 10 and thus the drive device and the motor vehicle also comprise a burner 12, by means of which, as will be explained in more detail below, at least one of the components, for example the first component 11 and/or the second component and/or the third component and/or the fourth component, can be heated up and/or kept warm quickly and efficiently, wherein the at least one component 11 is arranged in particular downstream of the burner 12. The burner 12 can burn a mixture, in particular by forming a flame, which results in burner exhaust gas from the burner 12, which provides the burner exhaust gas. For example, the burner exhaust gas or the flame can be introduced into the exhaust system 10 at an inlet point E, i.e. into an exhaust duct 14 of the exhaust system 10 through which the exhaust gas can flow. This means that the burner 12 is arranged at the inlet point E, so to speak. As is particularly evident in 2 As can be seen, the exhaust gas of the internal combustion engine is guided via an inflow line 15 in the exhaust duct 14 to the inlet point E of the burner 12 and released into the exhaust duct 14. Of course, the inflow line 15 can be dispensed with, so that the exhaust gas of the internal combustion engine flows from the turbine into the exhaust duct 14. For example, the inlet point E is arranged upstream of the second component, upstream of the third component and upstream of the fourth component and downstream of the first component. In other words, for example, the burner 12 is arranged upstream of the second component, upstream of the third component and upstream of the fourth component and downstream of the first component. Alternatively and in 2 shown, it is conceivable that the burner 12 or the inlet point E is arranged upstream of the first component 11 and in particular downstream of the turbine. The aforementioned, in the burner 12 or with The mixture to be burned by means of the burner 12 comprises air and a preferably liquid fuel. For example, in the embodiment shown in the figures, the fuel mentioned above is used as the fuel. Alternatively or additionally, at least a portion of the air that is fed to the burner 12 and used to form the mixture can come from the intake tract, for example.

For example, a fuel supply path is provided which is or can be connected fluidically to the burner 12 on the one hand and fluidically to a fuel line on the other hand. The fuel can flow through the fuel line from the tank to the injectors or to the fuel distribution element. In particular, the fuel supply path is fluidically connected to the fuel line at a first connection point, the first connection point being arranged downstream of the low-pressure pump and upstream of the high-pressure pump in the flow direction of the fuel flowing from the tank to the fuel distribution element or to the respective injector. At the first connection point, at least part of the fuel flowing through the fuel line, in particular liquid fuel, can be branched off from the fuel line and introduced into the fuel supply path. The fuel introduced into the fuel supply path can flow through the fuel supply path and is guided as valuable fuel to and in particular into the burner 12 by means of the fuel supply path. For example, a first valve element is arranged in the fuel supply path, by means of which an amount of fuel flowing through the fuel supply path and thus to be supplied to the burner 12 can be set. For example, an electronic computing device, also referred to as a control unit, is provided, by means of which the first valve element can be controlled, so that the amount of fuel flowing through the fuel supply path and to be supplied to the burner 12 can be adjusted, in particular regulated, by means of the control unit via the first valve element. The fuel supply path preferably has a controlled pump or a regulated pump for conveying the fuel from the tank to the burner 12.

Furthermore, for example, an air supply path is provided, via which or by means of which the burner can be supplied with the air for forming the mixture. This means that the air from which the mixture is formed can flow through the air supply path. In this case, a pump, also referred to as an air pump, is arranged in the air supply path, for example, by means of which the air can be conveyed through the air supply path and thus to the burner 12. For example, the low-pressure pump, also referred to as a low-pressure fuel pump, is referred to as a fuel pump, by means of which the fuel is conveyed through the fuel supply path and thus to the burner 12. The air supply path is fluidically connected to the intake tract, for example at a second connection point. Thus, for example, a second connection point can branch off at least part of the fresh air flowing through the intake tract from the intake tract and introduce it into the air supply path. The fresh air introduced into the air supply path can flow through the air supply path as the air for forming the mixture and is guided to and in particular into the burner 12 by means of the air supply path. In this case, for example, a second valve element is arranged in the air supply path, by means of which the amount of air flowing through the air supply path and thus flowing through the burner 12, which is used to form the mixture, can be adjusted. In this case, for example, the control device is designed to control the second valve element so that, for example, by means of the control device via the second valve element, the amount of air flowing through the air supply path and thus being supplied to the burner 12, which is used to form the mixture, can be adjusted, in particular regulated. The air supply path preferably has a controlled or regulated pump for conveying air, in particular fresh air or ambient air. The air is preferably sucked in by the pump via an air filter of the air supply path and conveyed to the burner 12.

As can be seen from the 1 , 2 and 4 As can be seen, the burner 12 has a combustion chamber 16 in which the mixture comprising the air supplied to the burner 12, also referred to as burner air, from which the mixture is formed, and the liquid fuel supplied to the burner 12 is to be ignited and thereby burned, that is to say ignited during operation of the burner 12 and thereby burned. For this purpose, an ignition device 18, designed for example as a spark plug or glow plug or glow pin, in particular electrically operable, is provided, which is for example a component of the burner 12. By means of the ignition device 18, at least one ignition spark can be generated in the combustion chamber 16, in particular using electrical energy or electrical current. By means of the ignition spark, the mixture in the combustion chamber 16 is ignited and subsequently burned, in particular by providing the burner exhaust gas and/or by providing the so-called flame. By means of the burner exhaust gas or by means of the flame, for example, the exhaust gas flowing through the exhaust tract 10, that is to say the exhaust gas flowing through the exhaust channel 14, can be heated up and/or kept warm quickly and efficiently, so that by means of the heated and/or kept warm exhaust gas (engine exhaust gas), which flows through the first component 11 and the other components, for example, can be heated up and/or kept warm quickly and efficiently.

The burner 12 has a first, inner swirl chamber 20 through which a first part of the air, also referred to as burner air, which is supplied to the burner 12, can flow or flows through and causes a first swirl-shaped flow of the first part of the air, and is therefore designed to cause a first swirl-shaped flow of the first part of the air. This is to be understood in particular that the first part of the air flows in a swirl shape through at least a first partial area of the swirl chamber 20 and/or flows out of the swirl chamber 20 in a swirl shape and/or flows into and thus in the combustion chamber 16 in a swirl shape. The inner swirl chamber 20 has, in particular precisely, a first outflow opening 22 through which the first part of the air can flow along a first passage direction of the outflow opening 22 and thus along a first flow direction coinciding with the first passage direction. The first part of the air from the inner swirl chamber 20 can be discharged into the combustion chamber 16 via the first outflow opening 22. This means that the first part of the air can flow out of the inner swirl chamber 20 via the first outflow opening 22. The burner 12 also comprises an introduction element 24, in the present case in the form of an electrically operated injection element, through which the liquid fuel that is fed to the burner 12 can flow. The introduction element 24 preferably has, in particular exactly, three outlet openings, also referred to as injection openings, through which the fuel fed to the introduction element 24 can flow, wherein the fuel flowing through the respective outlet openings flows out of the introduction element 24, in particular as a whole. For example, the respective outlet openings are designed as a particularly round bore. The respective outlet opening can be flowed through by the fuel, for example, along a respective second passage direction, so that the fuel flowing through the introduction element 24 can be sprayed out of the introduction element 24 via the respective outlet opening and can be injected, in particular directly, into the inner swirl chamber 20 and thus introduced. The second passage direction is preferably slightly inclined to the axial direction of the swirl chamber 20, the axial direction of which coincides, for example, with the aforementioned first passage direction. Furthermore, for example, the axial direction of the swirl chamber 20 coincides with a burner longitudinal axis of the burner 12, which extends, for example, elongated along its burner longitudinal axis, and in particular, the swirl chamber 20 and/or the combustion chamber 16 can be designed to be rotationally symmetrical with respect to the burner longitudinal axis. The introduction element 24 is designed in particular to spray the fuel out of the outlet openings (not specified in more detail) in a timed manner and thus to inject it into the swirl chamber 20 in a timed manner, in particular to spray it onto a surface 26 which directly delimits the swirl chamber 20 to the outside, in particular in the radial direction of the swirl chamber 20 and is designed as an inner peripheral surface. In other words, the swirl chamber 20 is directly delimited at least partially, in particular at least predominantly and thus at least more than half or completely, by the surface 26, which in the present case is an inner peripheral surface.

The respective second passage direction of the respective outlet opening coincides with a respective second flow direction along which the fuel can flow through the respective outlet opening and thus flow out of the introduction element 24 (injection element). The fuel can be sprayed out of the introduction element 24 via the respective outlet opening, in particular with the formation of a respective fuel jet, and can thereby be injected, in particular directly, into the swirl chamber 20. For example, the respective fuel jet, the longitudinal center axis of which coincides, for example, with the respective second passage direction or with the respective second flow direction, is at least substantially club-shaped or conical. In addition, for example, the introduction element 24 has a longitudinal direction or longitudinal extension or longitudinal extension direction which runs parallel to the first passage direction and thus parallel to the first flow direction and parallel to the axial direction of the inner swirl chamber 20, in particular coincides with the first passage direction and thus with the first flow direction and thus in particular with the axial direction of the inner swirl chamber 20. For example, the respective second passage direction runs perpendicularly or, in this case, obliquely to the first passage direction and thus to the first flow direction and to the axial direction of the inner swirl chamber 20 and the first outflow opening 22.

The inner swirl chamber 20 is at least partially, in particular at least predominantly and thus more than half or completely formed or limited by a component 28 of the burner 12, so that component 28 also forms or limits the first outflow opening 22, in particular directly. Thus, component 28 forms, for example, surface 26. Component 28 is also referred to as prefilmer or film layer.

The burner 12 furthermore has an outer swirl chamber 30 which surrounds at least a length region and in this case also the first outflow opening 22 in the circumferential direction of the inner swirl chamber 20, in particular completely encircling it, in the axial direction of the inner swirl chamber 20. In this case, the component 28, for example, has a partition wall 32 which is arranged between the swirl chambers 20 and 30 in the radial direction of the inner swirl chamber 20 and thus in the radial direction of the outer swirl chamber 30, the radial direction of which coincides with the radial direction of the swirl chamber 20. As a result, the swirl chambers 20 and 30, the axial directions of which coincide, are separated from one another in the radial direction of the swirl chambers 20 and 30 by the partition wall 32. The axial direction of the swirl chamber 20 coincides with the axial direction of the swirl chamber 30, wherein the radial direction of the swirl chamber 20 coincides with the radial direction of the swirl chamber 30. A second part of the air which is supplied to the burner 12 can flow through the outer swirl chamber 30 and is designed to cause a second swirling flow of the second part of the air. This means that the second part of the air flows through the swirl chamber 30 in a swirl shape and/or flows out of the swirl chamber 30 in a swirl shape and/or flows into and thus in the combustion chamber 16 in a swirl shape. In particular, it is preferably provided that the second part of the air flows in a swirl shape through at least a second partial region of the outer swirl chamber 30 and/or flows out of the swirl chamber 30 in a swirl shape and/or flows into and thus in the combustion chamber 16 in a swirl shape.

The outer swirl chamber 30 has, in particular precisely, a second outflow opening 34 through which the second part of the air flowing through the outer swirl chamber 30 can flow, in particular along a third flow direction, the third passage direction of which coincides with the third flow direction and along which the outflow opening 34 can be flowed through by the second part of the air flowing through the swirl chamber 30, in this case coincides with the axial direction of the swirl chamber 30 and thus the axial direction of the swirl chamber 20. The third passage direction coincides with the third flow direction along which the second part of the air flowing through the outer swirl chamber 30 flows or can flow through the outflow opening 34. This means in particular that the first passage direction coincides with the third passage direction and the first flow direction coincides with the third flow direction, so that in the present case the first flow direction, the third flow direction, the first passage direction and third passage direction coincide with the axial direction of the swirl chamber 20 and with the axial direction of the swirl chamber 30. In the flow direction of the air flowing through the swirl chambers 20 and 30, in particular the outflow openings 22 and 34, the second outflow opening 34 is arranged downstream of the first outflow opening 22 and is arranged or connected in series with the outflow opening 22 in particular, so that the second part of the air, the first part of the air and the fuel can flow through the second outflow opening 34. In particular, the first part of the air is already mixed with the fuel in the swirl chamber 20, in particular due to the swirling first flow, in particular to form a partial mixture. The partial mixture can flow through the outflow opening 22 and thus flow out of the swirl chamber 20 and then flow through the second outflow opening 34 and is mixed with the second part of the air, in particular due to the advantageous, second swirl-shaped flow, whereby the mixture is prepared particularly advantageously, thus the partial mixture is mixed particularly advantageously with the second part of the air.

It can be seen that the swirl chamber 30 is at least partially, in particular at least predominantly and thus at least more than half or completely, delimited in the radial direction of the respective swirl chamber 20, 30 towards the inside by the component 28, in particular by the partition wall 32. In particular, the swirl chamber 20 is delimited outwards in the radial direction of the respective swirl chamber 20, 30 at least partially, in particular at least predominantly or completely, by the component 28, in particular by the partition wall 32. In the radial direction of the respective swirl chamber 20, 30 towards the outside, the outer swirl chamber 30 is delimited at least partially, in particular at least predominantly or completely, by a component 36 of the burner 12. In particular, the swirl chamber 20 is delimited outwards in the radial direction of the swirl chamber 20, 30 at least partially by the surface 26, in particular directly. The swirl chamber 30 is delimited in the radial direction of the respective swirl chamber 20, 30 to the outside at least partially by a second surface 38, which in the present case is designed as an inner peripheral surface, in particular directly, wherein the second surface 38 is formed in particular by the component 36.

In the embodiment shown in the figures, it is provided that the component 36 and the component 28 are components that are formed separately from one another and in particular are connected to one another. The component 28 is arranged at least partially, in particular at least predominantly, in the component 36. The second outflow opening 34 is, for example, at least partially, in particular at least predominantly and thus at least more than half or completely, delimited or formed by the component 36 or the second outflow opening 22 is, for example, partially delimited or formed by the component 36 and partially by the component 28, in particular directly in each case, in particular with regard to the smallest or smallest flow cross section of the outflow opening 34 through which the second part of the air can flow.

Particularly good looking 1 to 4 it can be seen that the combustion chamber 16 is at least partially, in particular at least predominantly or completely, delimited, in particular directly, by a chamber element 40 of the burner 12. In particular, the chamber element 40 has a surface 42 designed as an inner peripheral surface, by which the combustion chamber 16 is at least partially directly delimited. In particular, the combustion chamber 16 is delimited in the radial direction of the respective swirl chamber 20, 30 towards the outside at least partially, in particular at least predominantly completely, preferably directly by the surface 42.

In the embodiments shown in the figures, as can be seen in particular from 3 As can be seen, the chamber element 40 has a wall 44 which is spaced apart from the outflow openings 22 and 34 in the axial direction of the respective swirl chamber 20, 30 and thus in the first or third flow direction, wherein the combustion chamber 16 is delimited by the wall 44, in particular by a surface 46 of the wall 44 and thus of the chamber element 40, in the axial direction of the respective swirl chamber 20, 30 and thereby in the first or third flow direction, thus in a delimitation direction running parallel to the axial direction in the respective swirl chamber 20, 30 and pointing away from the swirl chambers 20 and 30. It is conceivable that the surfaces 42 and 46 are components of an overall inner peripheral surface of the chamber element 40. As can be seen particularly well from 3 As can be seen, the wall 44 is penetrated by a plurality of through openings 48 which completely penetrate the wall 44. In the exemplary embodiment shown in the figures, the through openings 48 are arranged one after the other and at a distance from one another in the circumferential direction running around the respective axial direction of the respective swirl chamber 20, 30 and are in particular evenly distributed. Furthermore, the through openings 48 are, for example, circular and thus designed as circles whose centers lie on a further circle whose center lies on the axial direction of the respective swirl chamber 20, 30. In particular, the swirl chamber 30 is designed to be rotationally symmetrical with respect to its axial direction and thus in particular with respect to the burner longitudinal axis.

The burner exhaust gas from the combustion chamber 16 can flow through the through openings 48 and thus flow out of the combustion chamber 16 via the through openings 48 and in particular flow into the exhaust tract 10, that is to say into the exhaust duct 14, at the inlet point E.

In 4 it is clear that the 4 The swirl-shaped flows, collectively designated 50, run in a swirl-shaped manner in the combustion chamber 16 in such a way that the swirl-shaped flows run in a helical or spiral shape around the respective axial direction of the respective swirl chamber 20, 30 and thus around the burner longitudinal axis. A first exhaust gas part of the burner exhaust gas can, for example, flow through the through opening 48 and thereby flow into the exhaust gas tract, in particular into the exhaust gas duct 14. A second exhaust gas part of the burner exhaust gas flows, for example, initially against the wall 44 and is thereby deflected by the wall 44 and in particular deflected back (arrow 52), in particular in the direction of the surface 42 and/or the outflow opening 34, whereupon, for example, at least part of the second exhaust gas part can flow through the through opening 48. This makes it possible to achieve particularly advantageous mixture preparation by means of the existing backflow (arrow 52) in the combustion chamber 16.

Particularly good looking 4 , 5 and 6 the component 28 and the component 36 can be seen. For example, the component 28 is at least partially inserted into the component 36. The component 28 and the component 36 form a swirl generating device 54 of the burner 12. The swirl generating device 54 comprises a first swirl generator 56, which are also referred to as first swirl generating elements and are designed, for example, as first guide vanes. The first swirl generators 56 are first swirl generators of the inner swirl chamber 20. In addition, the component 28 has the first swirl generators 56. The swirl generating device 54 also comprises second swirl generators 58, which are also referred to as second swirl generating elements. In particular, the second swirl generators 58 are, for example, second guide vanes. The second swirl generators 58 are second Swirl generator of the outer swirl chamber 30. In addition, it is provided here that the component 36 has the second swirl generators 58. The first swirl-shaped flow of the first part of the air in the inner swirl chamber 20 is generated by means of the first swirl generator 56, and the second swirl-shaped flow of the second part of the air in the outer swirl chamber 30 is generated by means of the second swirl generator 58. The swirl generators 56 and 58 are arranged one after the other in the circumferential direction running around the axial direction of the respective swirl chamber 20, 30 and in particular are spaced apart from one another, in particular such that swirl channels 60 and 62 are arranged between the swirl generators 56 and 58 in the circumferential direction of the respective swirl chamber 20, 30. The swirl channels 60 and 62 are therefore arranged one after the other in the circumferential direction of the respective swirl chamber 20, 30 and at a distance from one another and are separated from one another in such a way that one of the respective swirl generators 56 and 58 is arranged between two of the swirl channels 60 and 62 in the circumferential direction of the respective swirl chamber 20, 30. It can be seen that the respective swirl channel 60, 62 is directly delimited on both sides in the circumferential direction of the respective swirl chamber 20, 30 by two of the swirl generators 56 and 58. In other words, for example, the respective swirl channel is directly delimited on both sides in the circumferential direction of the respective swirl chamber 20, 30 by respective surfaces 64, in particular of the component 28. Accordingly, the respective swirl channel 62 is directly delimited on both sides in the circumferential direction of the respective swirl chamber 20, 30 by respective surfaces 65, in particular of the component 36. The component 28 or the inner swirl chamber 20 is also referred to as prefilmer or film layer.

In particular, the swirl generators 56 form a first swirl generating device 55 of the inner swirl chamber 20, wherein the first swirl-shaped flow of the first part of the air can be effected or is effected by means of the swirl generating device 55. Furthermore, the second swirl generators 58 form a second swirl generating device 57 of the outer swirl chamber 30, wherein the second swirl-shaped flow of the second part of the air can be effected or is effected by means of the second swirl generating device 57. It can also be seen that the swirl generating devices 55 and 57 are components of the swirl generating device 54. The swirl generating device 55 is formed by the component 28, and the swirl generating device 57 is formed by the component 36.

The first outflow opening 22 ends, for example, in the flow direction of the first part of the air flowing through the first outflow opening 22 at a preferably specifically machined, sharp-edged end edge K ( 6 ), which is formed by an atomizer lip 67, in particular designed as a solid body, which can taper in the flow direction of the first part of the air flowing through the first outflow opening 22 up to the end edge K and ends, for example, at the end edge K. In this case, the atomizer lip 67 is in particular a component of the component 28 or is formed by the component 28. In other words, in order to be able to heat up the first component 11, which is designed, for example, as an exhaust gas aftertreatment device or as an exhaust gas aftertreatment system, particularly quickly and efficiently, in particular when the exhaust gas from the internal combustion engine has only a low temperature, it is preferably provided that the first outflow opening 22 ends in the flow direction of the first part of the air flowing through the first outflow opening 22 and thus in the flow direction of the fuel flowing through the first outflow opening 22 at the preferably specifically machined and thus sharp or razor-sharp end edge K, which is formed by the atomizer lip 67, which is designed in particular as a solid body and which preferably tapers in the flow direction of the first part of the air flowing through the first outflow opening 22 and thus in the flow direction of the fuel flowing through the first outflow opening 22, in particular up to the end edge K and in particular ends at the end edge K. This means that the atomizer lip 67 has a taper that tapers in the first flow direction and thus in particular towards the combustion chamber 16, which tapers, in particular, only ends at the end edge K. As a result of this and in particular as a result of the targeted machining of the end edge K, the taper or the atomizer lip 67 has sharp edges. In other words, the atomizer lip 67 ends with sharp edges, which allows a particularly advantageous mixture preparation to be achieved.

In the present case, the particularly razor-sharp end edge K is formed by the atomizer lip 67, which in the present case is formed by the component 28. In particular, the atomizer lip 67 tapers in the flow direction of the first part of the air flowing through the first outflow opening 22 and thus in the flow direction of the fuel flowing through the first outflow opening 22 up to the end edge K and ends at the end edge K.

In this case, it is particularly conceivable that the component 28, in particular its inner peripheral surface which at least partially and directly delimits the inner swirl chamber 20 in the radial direction of the swirl chamber 20 outwards, (Surface 26), is a film layer or functions as a film layer between the swirl chambers 20 and 30 and thus between the swirl-shaped and thus twisted flows, also referred to as air flow. In particular, it is conceivable that the inner peripheral surface or the film layer is formed by the aforementioned partition wall 32. In this case, by means of the introduction element 24, the fuel flowing through the outlet opening and thus emerging from the introduction element 24, in particular sprayed out, is applied to the film layer, in particular to the surface 26, or atomized onto the film layer, in particular as a film, also referred to as a fuel film. Due to centrifugal forces resulting from the swirling, first flow of the first part of the air, the fuel that has exited the introduction element 24, in particular has been sprayed out, and is thereby introduced, in particular injected, i.e. sprayed into the inner swirl chamber 20, in particular directly, is deposited, in particular as the aforementioned film, on the film layer, in particular on the surface 26, and flows or streams downstream to the first outflow opening 22 and thus to the end edge K. As a result, the fuel is applied to the atomizer lip 67 and conveyed or transported to the end edge K. Preferably, the first outflow opening 22 ends at the preferably razor-sharp end edge K, which here has or provides only a small area due to the previously described tapering, so that no excessively large droplets of the fuel can form on the end edge K. Due to the appropriate design of the atomizer lip 67 and in particular of the end edge K, only tiny droplets of the fuel break off at the end edge K. In other words, only very small, i.e. tiny, droplets are formed from the aforementioned fuel film at the end edge K, which break off at the end edge K, in particular from the atomizer lip 67 or from the component 28, and have a correspondingly large surface area. This effect leads to a particularly low-soot combustion of the mixture in the combustion chamber 16.

This allows tiny droplets of fuel to be produced without the need for high, laboriously generated fuel injection pressures and without expensive injection elements, so that on the one hand the costs of the burner 12 can be kept particularly low. On the other hand, particularly small droplets of fuel can be produced, so that very small outputs of the burner 12 can also be achieved.

How particularly good 5 and 6 in conjunction with 1 and 4 As can be seen, the first part of the air in the inner swirl chamber 20 can be fed from the outside inwards in the radial direction of the other swirl chamber, and can therefore be introduced into the inner swirl chamber 20 from the outside inwards in the radial direction of the inner swirl chamber 20. The second part of the air in the outer swirl chamber 30 can be fed from the outside inwards in the radial direction of the outer swirl chamber 30, and can therefore be introduced into the outer swirl chamber 30 from the outside inwards in the radial direction of the outer swirl chamber 30. This is to be understood in particular that the first part of the air or the second part of the air can be introduced into the respective swirl chamber 20, 30 in a respective flow plane, that is to say in a respective inflow direction running in the respective flow plane, wherein the flow plane runs perpendicular to the axial direction of the respective swirl chamber 20, 30. This is implemented in the burner 12 in such a way that the first part of the air can be introduced into the swirl chamber 20 via the swirl channels 60, and thus can be fed to the swirl chamber 20, wherein the second part of the air can be fed to the outer swirl chamber 30 via the swirl channels 62, and thus can be introduced into the outer swirl chamber 30, wherein the first part of the air can flow through the respective swirl channel 60 in the flow plane mentioned and viewed in the radial direction of the swirl chamber 20 from the outside inwards, and wherein the respective swirl channel 62 in the flow plane mentioned and viewed in the radial direction of the swirl chamber 30 from the outside inwards can be flowed through by the second part of the air.

In the embodiment shown in the figures, it is particularly provided that the respective swirl channel 60 can be flowed through in a fourth flow direction by a respective part of the first part of the air and in the radial direction of the swirl chamber 20 from the outside to the inside, in order to thereby supply the first part of the air to the swirl chamber 20, thus introducing it into the swirl chamber 20, wherein the fourth flow direction runs in a first flow plane which is perpendicular to the axial direction of the swirl chamber 20. Accordingly, the respective swirl channel 62 can be flowed through in a fifth flow direction and in the radial direction of the swirl chamber 30 from the outside to the inside by a respective part of the second part of the air, in order to thereby supply the second part of the air to the swirl chamber 30, thus introducing it into the swirl chamber 30, wherein the fifth flow direction runs in a second flow plane which is perpendicular to the axial direction of the swirl chamber 30. It is conceivable that the first flow plane and the second flow plane are spaced apart from one another, in particular in the axial direction of the respective swirl chamber 20, 30, or the flow planes coincide.

In order to achieve particularly advantageous operation of the burner 12 even over a long service life of the burner 12 In order to be able to do this, the surface 26 and/or the surface 38 and/or the surface 42 and/or the surface 46 is formed by a coating with which a base body carrying the coating is provided. In particular, it is conceivable that the surface 26 delimits the outflow opening 22, in particular directly. Alternatively or additionally, for example, the surface 38 delimits the outflow opening 34, in particular directly. In addition, the surfaces 42 and 46 each delimit the combustion chamber 16 at least partially and in particular directly. Furthermore, it is conceivable, for example, that the surface 64 and/or 65, which at least partially directly delimits the respective swirl channel 60 or 62, is formed by a coating with which a base body carrying the coating is provided. The feature that at least one of the surfaces 26, 38, 42, 46, 64 and 65 is formed by a coating with which a base body carrying the coating is provided is in 8th using the example of the respective surface 64 and thus of the component 28. It can be seen that the respective surface 64 completely and directly delimits the respective swirl channel 60. The respective surface 64 is defined by the aforementioned, in 8th The coating designated 66 is formed, with which the 8th with 68, which carries the coating 66. In particular, the respective coating 66 is applied to the base body 68. The base body 68 is, for example, formed in one piece, thus made from a single piece. In the case of the 8th In the exemplary embodiment shown, the base body 68 is only locally provided with the coatings 66, so that the coatings 66 are spaced apart from one another. In the context of a method for producing the component 28, for example, the base body 68 is first produced and provided and then, that is to say after the production of the base body 68, in particular locally, provided with the respective coating 66, which forms the respective surface 64, which directly delimits the respective swirl channel 60, in particular completely. In this case, for example, the base body 68 is formed from a first material, wherein the respective coating 66 is formed from a second material that is different from the first material. It can also be seen that the component 28 comprises the base body 68 and the respective coating 66. In other words, the base body 68 and the respective coating 66 are part of the component 28. The base body 68 is preferably formed in one piece, i.e. formed from a single piece. For example, the coating 66 is applied to the base body 68 by a thermal spraying process.

In 7 a flow of the engine exhaust gas is schematically illustrated and shown with 70. The flow 70 of the engine exhaust gas occurs, for example, when the internal combustion engine is in fired operation and provides the engine exhaust gas, which flows through the exhaust tract 10, while the burner 12 is deactivated, that is, while the burner 12 does not provide any burner exhaust gas. 7 it can be seen that at least a part of the exhaust gas flowing through the exhaust tract 10 or the exhaust duct 14 can then flow from the exhaust duct 14 into the combustion chamber 16, in particular via the through opening 48, and penetrate to the swirl generating devices 55 and 57 and thus to the swirl generators 56 and 58.

Any components contained in the engine exhaust gas, such as soot, can, for example, be deposited on the surface 64, which can lead to an undesirable narrowing or tapering of the cross-section of the swirl channels 60. This is also referred to as coking of the swirl channels 60 or of the swirl generation device 55. In order to avoid excessive deposits on the surfaces 64 or to avoid excessive, undesirable cross-section tapering and/or to be able to counteract excessive deposits on the respective surface 64, the respective surface 64 is formed by the respective coating 66. The respective coating 66 is preferably designed in such a way that any soot deposits on the surface 64 can be easily removed, in particular burned and thereby removed. For this purpose, for example, the coating 66 or the second material from which the coating 66 is formed is catalytically active for oxidation of soot deposited on the surface 64 and thus on the coating 66. For this purpose, the coating 66 comprises, for example, at least cerium oxide and/or at least one precious metal such as gold and/or platinum.

In order to further reduce the deposit of soot, a metallocene, in particular ferrocene, can be added to the fuel. In particular, the ferrocene can be added to the contents of the tank as an additive.

List of reference symbols

10

Exhaust system

11

component

12

burner

14

Exhaust duct

15

Inflow line

16

Combustion chamber

18

Ignition device

20

inner swirl chamber

22

first outlet opening

24

Injection element

26

surface

28

Component

30

outer swirl chamber

32

partition wall

34

second outlet opening

36

Component

38

surface

40

Chamber element

42

surface

44

Wall

46

surface

48

Passage opening

50

Currents

52

Arrow

54

Swirl generating device

55

first swirl generation device

56

first swirl generator

57

second swirl generating device

58

second swirl generator

60

first swirl channel

62

second swirl channel

64

surface

65

surface

66

Coating

67

Atomizer lip

68

Base body

70

flow

E

Discharge point

K

End edge

Claims (8)

Burner (12) for an exhaust tract (10) through which exhaust gas from an internal combustion engine of a motor vehicle can flow, comprising: - a combustion chamber (16) in which a mixture comprising air and a fuel is to be ignited and thereby burned, - an inner swirl chamber (20) through which a first part of the air can flow, which has a first swirl generating device (55) by means of which a swirl-shaped flow (50) of the first part of the air can be brought about, and a first outflow opening (22) through which the first part of the air flowing through the inner swirl chamber (20) can flow, via which the first part of the air can be discharged from the inner swirl chamber (20), - an introduction element (24) through which the fuel can flow, by means of which the fuel can be introduced into the inner swirl chamber (20), the first outflow opening (22) of which can also be flowed through by the fuel discharged from the introduction element (24), and - a combustion chamber (20) with at least one length region of the inner swirl chamber (20) in the circumferential direction of the inner swirl chamber (20) and through which a second part of the air can flow, outer swirl chamber (30), which has a second swirl generating device (57), by means of which a swirl-shaped flow (50) of the second part of the air can be brought about, and a second outflow opening (34) through which the second part of the air flowing through the outer swirl chamber (30), the fuel flowing through the first outflow opening (22) and the first part of the air flowing through the inner swirl chamber (30) and the first outflow opening (22) can flow, via which the parts of the air and the fuel can be introduced into the combustion chamber (16), wherein at least one surface (26, 38, 64, 65), which at least partially directly delimits the inner swirl chamber (20) and/or the outer swirl chamber (30), is formed by a coating (66), with which a base body carrying the coating (66) (68) of the burner (12) and the coating (66) is catalytically active. Burner (12) to Claim 1 , characterized in that the coating (66) is catalytically active for oxidation of soot deposited on the coating (66). Burner (12) according to one of the preceding claims, characterized in that the coating (66) comprises at least cerium oxide. Burner (12) according to one of the preceding claims, characterized in that the coating (66) comprises at least one precious metal. Burner (12) according to one of the preceding claims, characterized in that at least one swirl channel (60, 62) of the inner swirl chamber (20) and/or the outer swirl chamber (30), through which air can flow and designed to effect the swirl-shaped flow (50), is at least partially directly delimited by the coating (66). Burner (12) according to one of the preceding claims, characterized in that the first part of the air can be supplied to the inner swirl chamber (20) in the radial direction of the inner swirl chamber (20) from the outside to the inside. Burner (12) according to one of the preceding claims, characterized in that the second part of the air can be supplied to the outer swirl chamber (30) in the radial direction of the outer swirl chamber (30) from the outside to the inside. Motor vehicle, with an internal combustion engine, by means of which the motor vehicle can be driven, and with an exhaust tract (10) through which exhaust gas from the internal combustion engine can flow, which exhaust tract has at least one burner (12) according to one of the preceding claims.