Burner for an exhaust system of an internal combustion engine

Abstract

Burner (46) for use in an exhaust gas stream of an internal combustion engine, with a combustion chamber (2) which forms a hot gas outlet (8), wherein a fuel outlet (30) of a fuel injector (5) and a fresh gas guide (4) open separately into the combustion chamber (2) and an ignition device (7) projects, characterized by a design of the fuel injector (5) such that fuel exits from the fuel outlet (30) unblocked in the direction of the ignition device (7).

Description

[0001] The invention relates to a burner for use in an exhaust system of an internal combustion engine. The invention further relates to an internal combustion engine with such a burner.

[0002] The emission limits applicable to internal combustion engines are becoming increasingly stricter. This applies particularly to internal combustion engines designed to power motor vehicles. In order to comply with these emission limits, the conversion capability of exhaust aftertreatment devices integrated into the exhaust systems of these internal combustion engines must be present as soon as possible after a cold start. This requires that the exhaust aftertreatment devices reach their light-off temperatures (also known as "light-off temperatures") as quickly as possible after a cold start, at which point sufficient effectiveness for exhaust aftertreatment can be assumed.

[0003] It is known to temporarily and specifically heat exhaust aftertreatment devices. This can be achieved both through engine-related measures aimed at causing an internal combustion engine to emit exhaust gas at a relatively high exhaust temperature, as well as through active heating measures, for example, using electric heaters or burners (cf. US 7,980,069 B2, US 3,460,916 A, US 2022 / 0 112 823 A1, US 2022 / 0 112 830 A1, WO 2022 / 200397 A1, and US 4,951,464 A). Such a burner can use the same fuel as the one intended for operating the internal combustion engine.

[0004] The invention is based on the object of improving a burner which is intended for use in an exhaust system of an internal combustion engine.

[0005] This problem is solved by the subject matter of the patent claims.

[0006] A burner according to the invention, which is intended for use in an exhaust system of an internal combustion engine, comprises a combustion chamber with a hot gas outlet. The hot gas outlet can preferably be the only hot gas outlet and furthermore preferably be formed by only one outlet opening. However, a plurality of outlet openings can also be provided, which, to jointly form only one hot gas outlet, are all arranged at one outlet end of the combustion chamber. The burner can furthermore have a fresh gas inlet, which, like the combustion chamber, can be delimited by a housing of the burner. Fresh gas, which can in particular be air, can be supplied to the burner and specifically to the combustion chamber via the fresh gas inlet. For this purpose, a fresh gas guide can connect the fresh gas inlet to the combustion chamber. The fresh gas is then provided for combustion with fuel that has also been introduced into the combustion chamber.For this purpose, the burner comprises a fuel injector. A fuel outlet of the fuel injector and a fresh gas guide open separately into the combustion chamber so that the fuel and the fresh gas are supplied to the combustion chamber separately and not already mixed. Such a separate supply of the fuel and the fresh gas can be advantageous in terms of the most compact design possible for the burner. The burner further comprises an ignition device for igniting the fuel or a fuel-fresh gas mixture in the combustion chamber. The ignition device is preferably electrical and is therefore based on a conversion of electrical energy into thermal energy. The ignition device is particularly preferably designed such that it generates one or more ignition sparks to ignite the fuel or the fuel-fresh gas mixture. Such an ignition device is often also referred to as a spark plug.Additionally or alternatively, the ignition device can also be designed to include a heating element. Such a heating device is often referred to as a glow plug.

[0007] According to the invention, such a burner is characterized by a fuel injector design such that fuel exits the fuel outlet unobstructed in the direction of the ignition device. This property is to be understood geometrically, so that, due to the corresponding design of the fuel injector, at least a portion of the fuel to be introduced into the combustion chamber has a direction of movement upon exiting the fuel outlet that points toward the ignition device and is unobstructed, so that a corresponding movement of this fuel up to the ignition device would not be obstructed by intervening components.

[0008] The design according to the invention enables advantageous operating behavior of the burner and, in particular, reliable ignition of the fuel or the fuel-air mixture in the combustion chamber to be realized despite the separate supply of the fuel and the fresh gas.

[0009] According to a preferred embodiment of a burner according to the invention, it can be provided that the fuel injector is designed such that the fuel exits the fuel outlet at an angle included with a longitudinal axis of the fuel injector of greater than 0° and preferably of at least 20°. As a result, the inventive orientation of the fuel exiting the fuel injector in the direction of the ignition device can be combined with a structurally advantageous integration of the fuel injector into the burner. This applies in particular if, as is preferably provided, the longitudinal axis of the fuel injector runs parallel and in particular coaxially to a longitudinal axis of the combustion chamber in at least a first section of the combustion chamber extending from the fuel outlet.The fuel injector can also form a fuel channel leading to the fuel outlet, preferably running rectilinearly in at least one end section, which runs (in particular coaxially) along the longitudinal axis of the fuel injector.

[0010] Furthermore, this angle can preferably be no more than 45°. This allows for an advantageous distribution of the fuel within the combustion chamber.

[0011] According to a preferred embodiment of a burner according to the invention, the fuel injector can further be designed such that a conically widening expansion of the fuel in the combustion chamber results. This can also have an advantageous effect on the most uniform distribution of the fuel within the combustion chamber and thus on advantageous operating behavior of the burner. An expansion angle of the conically widening expansion of the fuel, i.e., the angle formed between two sections opposite each other with respect to a central axis of the conical shape of the fuel expansion, can preferably be between 40° and 90°.

[0012] According to a preferred embodiment of a burner according to the invention, the combustion chamber can extend from an inlet end to the hot gas outlet, which is arranged at the outlet end of the combustion chamber, wherein the fuel outlet of the fuel injector and / or the opening of the fresh gas guide are arranged in a wall delimiting the inlet end of the combustion chamber, and the ignition device is arranged in a wall circumferentially delimiting the combustion chamber. As a result, the ignition device can advantageously be arranged at a sufficient distance from the fuel outlet of the fuel injector and the opening of the fresh gas guide, whereby it can be achieved that the fuel introduced into the combustion chamber and the fresh gas have already mixed sufficiently well in the region of the ignition device to ensure reliable ignition of the fuel-fresh gas mixture.At the same time, the ignition device can be arranged in an edge region of the combustion chamber, which ensures that the ignition device is exposed as little as possible to a flame resulting from combustion of the fuel-fresh gas mixture, which should advantageously be formed primarily in a central section of the combustion chamber. As a result, the thermal load on the ignition device can be kept relatively low and, as a result, the device can be designed relatively cost-effectively. Although positioning the ignition device on the edge can have a disadvantageous effect on ensuring reliable ignition of the fuel-fresh gas mixture, this can be compensated for by the inventive orientation of the fuel exiting the fuel outlet of the fuel injector towards the ignition device.

[0013] According to a preferred embodiment of a burner according to the invention, a wall element can also be provided which is arranged within the combustion chamber and which partially blocks an opening cross-section of the combustion chamber, whereby the combustion chamber is divided into a primary chamber and a secondary chamber, wherein the fuel outlet of the fuel injector, the mouth of the fresh gas guide, and the ignition device are located in the primary chamber. In contrast, the hot gas outlet is located in the secondary chamber. The wall element can preferably be arranged centrally within the combustion chamber, so that it is also arranged in the region of the longitudinal axis of the combustion chamber in the corresponding opening cross-section.Particularly preferably, it can be provided that the wall element is arranged substantially over its entire circumference, possibly with the exception of fastening elements with which the wall element is positioned within the combustion chamber, at a distance from a wall which delimits the combustion chamber on the circumference.

[0014] For the preferably immovable positioning of the wall element, it can be connected to a wall of the burner, in particular a wall that surrounds the combustion chamber on the circumference, by means of one or more supports, wherein the one support or the multiple supports delimit one or more overflow openings with the wall element and the wall. Furthermore, the wall element can preferably be designed to be free of openings, at least in its center. Such a wall element can stabilize a flame resulting from the combustion of a mixture of the fuel and the fresh gas within the primary chamber. It can also be provided that combustion of such a mixture takes place exclusively or primarily in the primary chamber, while the secondary chamber can serve merely to guide the hot gas resulting from such combustion.However, combustion, particularly post-combustion of fuel, can also occur in the secondary chamber.

[0015] In order to achieve a sufficiently high thermal resistance, it can preferably be provided that the wall element is at least partially made of a metal (e.g. steel) and / or a ceramic.

[0016] The wall element can preferably have a peripheral shape adapted to the opening cross-section. In particular, the opening cross-section and / or the peripheral shape of the wall element can be circular. Any other shapes of the opening cross-section and / or the peripheral shape of the wall element are also possible.

[0017] The wall element can be designed to be flat or (concave or convex) curved, at least on the side facing the primary chamber.

[0018] An advantageous functionality of the wall element with regard to the intended stabilization of the flame can be achieved by aligning the wall element perpendicular to a longitudinal axis of the primary chamber and / or the longitudinal axis of the fuel injector.

[0019] An advantageous functionality of the wall element with regard to the intended stabilization of the flame can also be achieved by having a geometric center of the wall element located on the longitudinal axis of the primary chamber and / or on the longitudinal axis of the fuel injector.

[0020] An advantageous compromise with regard to the functionality aimed at by the wall element for stabilizing the flame on the one hand and with regard to an overflow of hot gas from the primary chamber into the secondary chamber on the other hand can be realized by the wall element blocking the opening cross-section of the combustion chamber to a value that is between 60% and 80%.

[0021] The burner's operating behavior can be advantageous if the ratio of a (greatest) length to a (greatest) width of the primary chamber is between 1:1 and 1:3. In the preferred design of the primary chamber with circular opening cross-sections, the width corresponds to the diameter.

[0022] It can also be beneficial with regard to the operating behavior of the burner if the ratio of the volumes of the primary chamber and the secondary chamber is between 2:1 and 1:2.

[0023] A structurally advantageous embodiment of the burner according to the invention can be achieved by having the combustion chamber extend in a straight line in a first combustion chamber section and in a second combustion chamber section, with the lines in the first section and the second section being aligned at an angle to one another. This allows for advantageous integration into the exhaust system of the internal combustion engine, particularly with regard to the required installation space.

[0024] According to an advantageous development of such a burner according to the invention, the first combustion chamber section can comprise the primary chamber and a first section of the secondary chamber. This can have an advantageous effect on the combustion of the fuel-fresh gas mixture and the flow of the hot gas generated thereby.

[0025] According to a preferred embodiment of a burner according to the invention, an opening of the fresh gas guide into the combustion chamber can be annular, in particular a closed annular, and can at least partially, preferably completely, surround the fuel outlet of the fuel injector. This allows for an advantageous mixing of fuel that has exited the fuel outlet of the fuel injector with fresh gas that has entered the combustion chamber via the opening.

[0026] The same purpose can be served if, as is preferably provided, a (first) swirl element for generating a swirl flow of the fresh gas is integrated into the mouth of the fresh gas guide into the combustion chamber. Integration is understood to mean an arrangement of the swirl element in which it influences the fresh gas entering or having entered the combustion chamber to generate the swirl flow. For this purpose, the swirl element can preferably be integrated into the mouth opening or form the mouth opening itself. However, it can also be positioned in front of or behind the mouth opening. Such a swirl flow leads to advantageous mixing of the fresh gas with the fuel. This mixing can then be further improved by having a second swirl element upstream of the first swirl element (with respect to the direction of the fresh gas flow).Such a second swirl element can also ensure the most even distribution of the fresh gas over the circumference of the orifice with the first swirl element integrated therein, which can also have an advantageous effect on the mixing of the fresh gas with the fuel.

[0027] It can also be advantageous with regard to the distribution of the fresh gas within the combustion chamber if the first swirl element is flowed against by the fresh gas axially and thus preferably also along a longitudinal axis of the combustion chamber in the region of the mouth of the fresh gas guide.

[0028] A structurally advantageous embodiment of a burner according to the invention can be realized by providing a (first) one-piece housing component that delimits the secondary chamber and forms the wall element. Furthermore, a second one-piece housing component can then also be provided, which circumferentially delimits the primary chamber and which is connected (in particular gas-tight) at a first end to an inlet element and at a second end to the first housing component, wherein the inlet element forms the opening of the fresh gas guide and accommodates the fuel injector. The ignition device, on the other hand, can preferably be integrated into the second housing component or accommodated therein.In addition, it can then advantageously be provided that the first housing component, the second housing component and the inlet element form an inner housing which is at least partially surrounded by an outer housing, wherein a section of the fresh gas guide which connects a fresh gas inlet of the burner formed by the outer housing to the combustion chamber is formed between the inner housing and the outer housing. The fresh gas guide can surround the combustion chamber in at least one section at least partially, preferably completely or as completely as possible. By means of this configuration of the fresh gas guide, an advantageous cooling effect can be achieved with regard to the outside of the housing of the burner, whereby advantageous integration into an internal combustion engine or into a motor vehicle which comprises such an internal combustion engine can be achieved.Furthermore, this design of the fresh gas guide allows preheating of the fresh gas before it enters the combustion chamber, which can have an advantageous effect on the combustion of fuel with the fresh gas within the combustion chamber.

[0029] All components of at least the housing of the burner can advantageously be designed in any configuration as a sheet metal component (i.e. as a component produced from a preferably metallic sheet by cutting and / or forming) or as a cast component or as a generatively manufactured component.

[0030] The invention also relates to an internal combustion engine comprising an internal combustion engine forming at least one combustion chamber and an exhaust system for discharging exhaust gas originating from the at least one combustion chamber. A burner according to the invention is integrated into the exhaust system. The burner can, in particular, be associated with at least one exhaust gas aftertreatment device, so that its operation is intended to heat the exhaust gas aftertreatment device in a targeted and as-needed manner. For this purpose, the burner can, in particular, be arranged directly upstream (with respect to the flow direction of exhaust gas in the exhaust system) of the exhaust gas aftertreatment device.Such heating can be provided in particular before or immediately after a cold start of the internal combustion engine when the exhaust gas aftertreatment device has a temperature that is below its light-off temperature, above which sufficient effectiveness for the intended exhaust gas aftertreatment can be assumed. However, such heating can also be provided to achieve a temporarily particularly high temperature of the exhaust gas aftertreatment device with the aim of regenerating the exhaust gas aftertreatment device. Furthermore, it can preferably be provided that the fuel injector is integrated into a fuel supply system of the internal combustion engine in order to supply it with fuel that is also provided for operating the internal combustion engine. Likewise preferably, it can be provided that the fresh gas inlet of the burner is fluidly connected to a fresh gas line of the internal combustion engine.Such a fresh gas line serves to supply fresh gas, which essentially consists of (ambient) air, to the internal combustion engine for combustion with fuel in at least one combustion chamber. A connecting line connecting the fresh gas line of the internal combustion engine to the fresh gas inlet of the burner can branch off, in particular, downstream of an air filter integrated into the fresh gas line, allowing purified fresh gas or purified air to be supplied to the burner.

[0031] The invention also relates to a motor vehicle, in particular a land vehicle, particularly preferably a wheel-based and non-rail-bound motor vehicle (preferably a car or a truck), with an internal combustion engine according to the invention. The internal combustion engine of the internal combustion engine can be provided, in particular, for the (direct or indirect) provision of the traction drive power for the motor vehicle.

[0032] The invention is explained in more detail below with reference to an exemplary embodiment illustrated in the drawing. The drawing shows, in a partially simplified representation: Fig. 1: a burner according to the invention, Fig. 2: a longitudinal section through the burner, Fig. 3: a first component of an inlet element of the burner, Fig. 4: a second component of the inlet element, Fig. 5: an inner part of a cover component of the burner and Fig. 6: an internal combustion engine according to the invention.

[0033] The one in the Fig. 1 and Fig. The burner 46 shown in Figure 2 comprises a housing 1 which defines a combustion chamber 2. The combustion chamber 2 extends from an inlet end to an outlet end. Perpendicular to this extension, the combustion chamber 2 has essentially circular opening cross-sections. The connection of the geometric centers of these opening cross-sections represents a longitudinal axis 27 of the combustion chamber. The outlet end of the combustion chamber 2 is defined by an inlet element 3 which, as part of the housing 1, forms the opening of a fresh gas guide 4 and an end section of a fuel injector 5 (in the Fig. 1 not shown).

[0034] The fresh gas guide 4 is delimited by the housing 1, which is partially double-walled for this purpose. This fresh gas guide 4 connects a fresh gas inlet 6 to the combustion chamber 2 and serves to introduce fresh gas, which was supplied to the burner 46 via the fresh gas inlet 6, into the combustion chamber 2, where the fresh gas mixes with fuel, which was introduced via the fuel injector 5. This fuel-fresh gas mixture can then be ignited in the combustion chamber 2, and specifically in a primary chamber 2a of this combustion chamber 2, by means of an electrical ignition device 7 (in the Fig. 1 not shown). The fuel-fresh gas mixture burning in this way leads to the generation of hot gas (exhaust gas from the combustion), which is discharged via a hot gas outlet 8 formed by the housing 1 at the outlet end of the combustion chamber 2 and into an exhaust system 21 of an internal combustion engine into which the burner 46 is integrated (cf. Fig. 6), can be initiated.

[0035] The division of the combustion chamber 2 into the primary chamber 2a and a secondary chamber 2b is achieved by means of a wall element 9 arranged centrally within an opening cross-section of the combustion chamber 2 and oriented perpendicularly with respect to the longitudinal axis 27 of the combustion chamber 2. This wall element 9 only partially blocks the opening cross-section of the combustion chamber 2 (in a central section), whereby a flame of the burning fuel-fresh gas mixture can be stabilized in a central region of the primary chamber 2a. The hot gas generated in the primary chamber 2a by combustion flows around the wall element 9 and thereby flows into the secondary chamber 2b, in which this hot gas flow is deflected by an angle of, for example, between 45° and 75° and then discharged via the hot gas outlet 8 arranged at the rear end of the secondary chamber 2b.The deflection of the hot gas flow results from an angular alignment of a first combustion chamber section 2c and a second combustion chamber section 2d, which each run straight.

[0036] A fuel outlet 30 is formed at a longitudinal axial (outlet) end of the fuel injector 5. The fuel outlet 30 can preferably be provided as a single, preferably annular outlet opening or as an annular arrangement of a plurality of outlet openings. A longitudinal axis 27 of the fuel injector 5 is arranged concentrically to the longitudinal axis 27 of the combustion chamber 2 in the region of the first combustion chamber section 2c. A fuel channel 59 (only partially in the Fig. 2) runs within the fuel injector 5 coaxially to the longitudinal axis 27 of the fuel injector 5.

[0037] The fuel injector 5 is designed in such a way that a conically widening expansion of the fuel (specifically with a straight cone shape) results in the primary chamber 2a, wherein in the specific embodiment example an expansion angle α of 40° or an angle α / 2 of 20° included with the longitudinal axis 27 is provided. An area of ​​the conical expansion is aligned unobstructed in the direction of the ignition device 7, as shown in the Fig. 2 is shown.

[0038] The fresh gas inlet 6 formed by the housing 1 is arranged in the region of the transition between the first combustion chamber section 2c and the second combustion chamber section 2d, wherein the direction of extension of the fresh gas inlet 6 and thus the direction of flow of the fresh gas entering the fresh gas guide 4 is oriented perpendicularly or radially with respect to the longitudinal axis 27 of the combustion chamber 2 in the region of the first combustion chamber section 2c. Starting from the fresh gas inlet 6, the fresh gas guide 4 is designed such that a main flow direction of the fresh gas in a first fresh gas guide section 4a of the fresh gas guide 4 is at least partially concurrent with a main flow direction of gas (hot gas) within the second combustion chamber section 2d.The “main flow direction” is understood to mean a direction of a flow of gas in the fresh gas guide 4 and the combustion chamber 2, which results from the structural design of the fresh gas guide 4 and the combustion chamber 2 as flow-guiding cavities as the most direct possible path for a flow of the respective gas from an inlet (fresh gas inlet 6 in the fresh gas guide 4; mouth of the fresh gas guide 4 into the combustion chamber 2 in the combustion chamber 2) to an outlet (mouth of the fresh gas guide 4 into the combustion chamber 2 in the fresh gas guide 4; hot gas outlet 8 in the combustion chamber 2).

[0039] A half-shell-shaped deflection element 10, which is an integral part of the housing 1, deflects the fresh gas entering the fresh gas guide 4 via the fresh gas inlet 6 in the direction of the outlet end of the combustion chamber 2.

[0040] Shortly before the hot gas outlet 8 of the combustion chamber 2, the fresh gas is deflected in the fresh gas guide 4 towards the inlet end of the combustion chamber 2, and the fresh gas thereby flows in a second fresh gas guide section 4b in the opposite direction to the main flow direction of the gas (hot gas and / or fuel-fresh gas mixture) in the first combustion chamber section 2c. At the inlet end of the combustion chamber 2, the flow of the fresh gas is deflected by almost 180° due to a corresponding design of the fresh gas guide 4 and then enters an annular prechamber 13 via an annular (second) swirl element 12, which is delimited by the inlet element 3. This second swirl element 12 comprises a plurality of annularly arranged guide elements 14, which are aligned obliquely with respect to the main flow direction in the first combustion chamber section 2c and between which passage openings are formed (see also Fig. 3), through which the fresh gas can flow, creating a swirling flow of the fresh gas. This swirling flow within the prechamber 13 ensures the most even distribution of the fresh gas possible over the circumference of the fuel injector 5, which is surrounded by the prechamber 13 of the inlet element 3 in a ring. This even distribution can compensate for an uneven distribution of the fresh gas on the inlet side of the second swirl element 12, which can result from the fresh gas being supplied unevenly to the second swirl element 12 as a result of the deflection by the deflection element 10 and a partial blockage of the flow guide in the fresh gas guide 4 by the ignition device 7 and a temperature sensor 15, which are accommodated in the housing 1 and extend into the combustion chamber 2, specifically into the primary chamber 2a. The fresh gas is discharged from the prechamber 13 via a further (first) swirl element 11 (see also Fig. 4), which corresponds to the second swirl element 12 except for different diameters, is introduced into the combustion chamber 2. The first swirl element 11 thus forms the opening of the fresh gas guide 4 into the combustion chamber 2.

[0041] The fresh gas duct 4 surrounds the combustion chamber 2 as completely as possible, thereby achieving a good transfer of thermal energy from the combustion chamber 2 to the fresh gas flowing through the fresh gas duct 4. This largely complete enclosure of the combustion chamber 2 is interrupted essentially only in those areas where the ignition device 7 and the temperature sensor 15 protrude through the housing 1 into the combustion chamber 2.

[0042] The housing 1 can preferably be designed in multiple parts. An inner housing can be provided which delimits the combustion chamber 2 on the inside. An outer housing surrounds the inner housing and thus delimits the fresh gas guide 4 on the inside and, in combination with the outside of the inner housing, forms the fresh gas guide 4. A first housing component 1a, which represents part of the inner housing, forms the walls that delimit the secondary chamber 2b. This first housing component 1a, which can preferably be designed in one piece, also comprises the wall element 9, which divides the combustion chamber 2 into the primary chamber 2a and the secondary chamber 2b, as well as supports 60, which connect the wall element 9 to a main part of the first housing component 1a. Alternatively, the wall element 9 can also be designed as a separate component that is connected to the supports 60 in any desired manner (positively, non-positively, and / or materially).Between the supports 60, several overflow openings 34 are formed, through which the hot gas can flow from the primary chamber 2a into the secondary chamber 2b. The supports 60 extend at an angle of less than 90° relative to the longitudinal axis 27 of the combustion chamber 2 in the region of the first combustion chamber section 2c.

[0043] A second housing component 1b defines the primary chamber 2a on the periphery. This second housing component 1b can advantageously be designed as a simple, rectilinear tube which, in addition to the end openings, has two peripheral openings for accommodating the ignition device 7 and the temperature sensor 15. The second housing component 1b can surround the first housing component 1a in one section and be connected to it in a gas-tight manner, for example by welding. A third housing component 1c forms the outer housing wherever the fresh gas guide 4 surrounds the inner housing. In an outlet section in the region of the outlet end of the combustion chamber 2, the combustion chamber 2 is not surrounded by the fresh gas guide 4 and thus also not by the third housing component 1c.In the area of ​​this outlet section, an annular connecting flange 16 is provided, which serves to securely connect the burner 46 to an exhaust pipe of the exhaust system 21 of the internal combustion engine. This connecting flange 16 can be connected, for example, welded, to the inner housing or the first housing component 1a and / or to the third housing component 1c.

[0044] The third housing component 1c forms a receiving opening within which a holder 17 is fastened, each forming a receiving opening 22, 23 for the ignition device 7 and the temperature sensor 15. The open end of the tubular, second housing component 1b is closed at the inlet end of the combustion chamber 2 by means of the inlet element 3. The inlet element 3 can be designed as a unit with a cover component 18. The cover component 18 closes the third housing component 1c in the region of the inlet end of the combustion chamber 2 and forms a receptacle for the fuel injector 5. The unit comprising the inlet element 3 and the cover component 18 represents a fourth housing component 1d.

[0045] The various housing components 1a, 1b, 1c, 1d can each be designed as a single piece or in multiple pieces, with a single-piece design being preferred for at least the first housing component 1a and the second housing component 1b. For the third housing component 1c and the fourth housing component 1d, however, multi-piece designs may be advantageous from a manufacturing perspective.

[0046] The fourth housing component 1d can comprise not only the inlet element 3 and the cover component 18 as these multiple parts, but these components can also advantageously be designed in multiple parts. Accordingly, the inlet element 3 comprises a first, disc-shaped component 61, which forms the second swirl element 12 (see FIG. Fig. 3) and a second, pot-shaped component 62, which forms the first swirl element 11 (cf. Fig. 4).

[0047] The cover component 18 consists of an annular inner part 24, which is shown in an isolated illustration in the Fig. 5, and a funnel-shaped outer part 25. The inner part 24 forms an annular cover plate 24a and a tubular extension 24b extending centrally from the cover plate 24a, the inner volume of which represents the receptacle for the fuel injector 5. An annular free space is formed between the inner part 24 and the outer part 25 of the cover component 18, which serves as a cooling jacket 26 for the fuel injector ("injector cooling jacket") and is part of a cooling device of the burner 46. Integrated into the cover plate 24a are two through openings 53, which serve as orifices, one of the orifices representing a cooling jacket inlet and the other of the orifices representing a cooling jacket outlet.These outlet openings are offset from one another by an angle of, for example, less than 25° with respect to the circumference of a longitudinal axis 27 of the tubular extension 24b, which is arranged coaxially with the longitudinal axis 27 of the fuel injector 5. A first partition 28 is arranged between the through-openings 53 and runs radially and parallel with respect to the longitudinal axis 27 of the tubular extension 24b. A second partition 29 is offset from the first partition 28 by 180° with respect to the longitudinal axis 27. The partitions 28, 29 divide the injector cooling jacket 26, which otherwise completely surrounds the fuel injector 5, with this division of the injector cooling jacket 26 extending only over a portion of the length of the tubular extension 24b starting from the cover plate 24a.In the region of a front end of the extension 24b and thus in the vicinity of an outlet end of the fuel injector 5, into which the fuel outlet 30 is integrated, the injector cooling jacket 26 surrounds the fuel injector 5 completely and thus without any subdivision by means of the partition walls 28, 29.

[0048] A further cooling jacket 31 is assigned to the ignition device 7. This igniter cooling jacket 31 is integrated into the holder 17 and surrounds the receiving opening 22 for the ignition device 7 essentially over its entire circumference, wherein a (single) partition wall 52 is also provided within the igniter cooling jacket 31, which extends radially and parallel with respect to a longitudinal axis 32 of the receiving opening 22 and, with respect to the circumference of this longitudinal axis 32, is located between two orifices (not visible), one of which serves as the cooling jacket inlet and the other as the cooling jacket outlet of the igniter cooling jacket 31.

[0049] A coolant connection flange 33 is connected to the outside of one of the openings in the cover plate 24a and one of the openings in the holder 17. The cooling device of the burner 46 can be integrated into a cooling system of the internal combustion engine via these coolant connection flanges 33. For this purpose, connecting lines (not shown), which are designed, for example, in the form of hoses, can be plugged onto the coolant connection flanges 33 and fixed thereon. The other openings of the cooling jackets 26, 31 are fluidically connected to one another via a coolant line 35 arranged completely outside the housing 1. This results in a serial integration of the cooling jackets 26, 31 into the cooling device of the burner 46, wherein it can be provided that the coolant flows first through the injector cooling jacket 26 and then through the igniter cooling jacket 31, as shown in the Fig. 1 is shown by way of example; or a reverse flow through the cooling device of the burner 46 is provided.

[0050] Fig. 6 shows an internal combustion engine according to the invention for a motor vehicle. This comprises an internal combustion engine 36, which is designed, for example, in the form of a reciprocating piston engine with four cylinder openings 37 arranged in series. The cylinder openings 37, with reciprocating pistons 38 guided therein and a cylinder head, each delimit a combustion chamber 39. During operation of the internal combustion engine 36, and thus of the internal combustion engine, fresh gas is supplied to these combustion chambers 39 via a fresh gas line 40, wherein the supply of fresh gas is controlled by inlet valves 41 assigned to the individual combustion chambers 39. The fresh gas is exclusively or primarily air drawn in from the environment. Exhaust gas is generated during the combustion of mixture quantities consisting of the fresh gas and fuel injected directly into the combustion chambers 4 via fuel injectors 42.This exhaust gas is discharged via the exhaust system 21 of the internal combustion engine, with the exhaust gas discharge from the individual combustion chambers 39 being controlled by exhaust valves 43. Ignition of the mixture in the combustion chambers 39 is achieved by means of electrical ignition devices 44, which, for example, generate ignition sparks (spark plugs).

[0051] The internal combustion engine is designed to be turbocharged, for which purpose a fresh gas compressor 54 is integrated into the fresh gas line 40. The fresh gas compressor 54 is part of an exhaust gas turbocharger, which further comprises an exhaust gas turbine 55 integrated into the exhaust line 21. Exhaust gas flowing through the exhaust gas turbine 55 results in a rotating drive of a turbine impeller, which is connected in a rotationally driving manner to a compressor impeller of the fresh gas compressor 54, so that the fresh gas compressor 54 is driven by the exhaust gas turbine 55.

[0052] The exhaust gas also flows through at least one exhaust gas aftertreatment device 45 integrated into the exhaust line 21, which is intended to remove components of the exhaust gas that are considered to be pollutants from the exhaust gas or to convert them into harmless components.

[0053] A portion of the exhaust gas conducted through the exhaust system 21 can, if required, be routed through an exhaust gas recirculation line 19 and introduced into the fresh gas system 40. This exhaust gas recirculation line 19, into which an exhaust gas recirculation valve 56 controllable by a control device (not shown) and an exhaust gas cooler 20 are integrated, branches off from the exhaust system 21 downstream of the exhaust turbine 55 and upstream of the exhaust gas aftertreatment device 45 and flows into the fresh gas system 40 upstream of the fresh gas compressor 54.

[0054] In order to enable heating of the exhaust gas aftertreatment device 45 as required, a burner 46 according to the invention is provided upstream of the latter, for example according to the Fig. 1 to 5. The cooling device of this burner 46 is further integrated into a cooling system of the internal combustion engine. This cooling system is in the Fig. 6 is shown in a highly simplified manner. This accordingly also includes a coolant pump 47 for conveying coolant in at least one coolant circuit, coolant channels 48, 57, 58 of the internal combustion engine 36, the exhaust gas turbocharger, and the exhaust gas cooler 20, as well as a coolant cooler 49 for recooling the coolant by transferring thermal energy to ambient air, which also flows through and around the coolant cooler 49.

[0055] In the Fig.6 also shows that the fresh gas inlet 6 of the burner 46 is fluidly connected to the fresh gas line 40 of the internal combustion engine via a fresh gas line 50, wherein the fresh gas line 50 branches off from the fresh gas line 40 downstream of an air filter 51. This allows air, which has already been purified by the air filter 51, to be supplied to the burner 46 as fresh gas as needed. LIST OF REFERENCE SYMBOLS 1 housing 1a first housing component 1b second housing component 1c third housing component 1d fourth housing component 2 combustion chamber 2a Primary chamber of the combustion chamber 2b Secondary chamber of the combustion chamber 2c first combustion chamber section 2d second combustion chamber section 3 Inlet element 4 Fresh gas supply 4a first fresh gas supply section 4b second fresh gas supply section 5 Burner fuel injector 6 Fresh gas inlet 7 Burner ignition device 8 Hot gas outlet 9 Wall element 10 Deflection element 11 first swirl element 12 second swirl element 13 Pre-chamber of the inlet element 14 Guide element of a swirl element 15 Temperature sensor 16 Connection flange 17 Bracket 18 Cover component 19 Exhaust gas recirculation line 20 exhaust gas coolers 21 Exhaust system 22 Opening for the ignition device 23 Opening for the temperature sensor 24 Inner part of the cover component 24a Cover plate of the cover component 24b Extension of the lid component 25 Outer part of the cover component 26 Injector cooling jacket 27 Longitudinal axis of the combustion chamber / fuel injector / extension 28 first partition wall of the injector cooling jacket 29 second partition wall of the injector cooling jacket 30 Fuel injector fuel leak 31 Igniter cooling jacket 32 Longitudinal axis of the receiving opening for the ignition device 33 Coolant connection flange 34 Overflow opening 35 coolant line 36 combustion engine 37 Cylinder opening 38 pistons 39 Combustion chamber 40 Fresh gas line 41 Inlet valve 42 Fuel injector of the combustion engine 43 Exhaust valve 44 Ignition device of the internal combustion engine 45 Exhaust aftertreatment device 46 burners 47 Coolant pump 48 Coolant channel of the combustion engine 49 Coolant cooler 50 Fresh gas line 51 air filters 52 Partition of the igniter cooling jacket 53 passage opening 54 fresh gas compressors 55 exhaust turbine 56 Exhaust gas recirculation valve 57 Coolant channel of the exhaust turbocharger 58 Coolant channel of the exhaust gas cooler 59 Fuel channel 60 support 61 first component of the inlet element 62 second component of the inlet element α expansion angle QUOTES CONTAINED IN THE DESCRIPTION

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

[0000] US 7 980 069 B2

[0003] US 3 460 916 A

[0003] US 2022 / 0 112 823 A1

[0003] US 2022 / 0 112 830 A1

[0003] WO 2022 / 200397 A1

[0003] US 4 951 464 A

[0003]

Claims

[1] Burner (46) for use in an exhaust system (21) of an internal combustion engine, with a combustion chamber (2) which forms a hot gas outlet (8), wherein a fuel outlet (30) of a fuel injector (5) and a fresh gas guide (4) open separately into the combustion chamber (2) and an ignition device (7) protrudes, characterized by a design of the fuel injector (5) such that fuel exits unobstructed from the fuel outlet (30) in the direction of the ignition device (7). [2] Burner (46) according to claim 1, characterized by a design of the fuel injector (5) such that the fuel exits the fuel outlet (30) at an angle of at least 20° enclosed with a longitudinal axis (27) of the fuel injector (5). [3] Burner (46) according to claim 2, characterized by that the angle is no more than 45°. [4] Burner (46) according to one of the preceding claims, characterized bya design of the fuel injector (5) such that a conically widening spread of the fuel in the combustion chamber (2) results. [5] Burner (46) according to one of the preceding claims, characterized by that the combustion chamber (2) extends from an inlet end to the hot gas outlet (8), wherein the fuel outlet (30) of the fuel injector (5) and / or the mouth of the fresh gas guide (4) are arranged in a wall delimiting the inlet end of the combustion chamber (2) and the ignition device (7) is arranged in a wall delimiting the combustion chamber (2) on the peripheral side. [6] Burner (46) according to one of the preceding claims, characterized bya wall element (9) which is arranged centrally within the combustion chamber (2) and partially blocks an opening cross-section of the combustion chamber (2), whereby the combustion chamber (2) is divided into a primary chamber (2a) and a secondary chamber (2b), wherein the fuel outlet of the fuel injector (5), the mouth of the fresh gas guide (4) and the ignition device (7) are located in the primary chamber (2a) and the hot gas outlet (8) is located in the secondary chamber (2b). [7] Burner (46) according to one of the preceding claims, characterized by that the wall element (9) is aligned perpendicular to a longitudinal axis (27) of the combustion chamber (2) and / or a / the longitudinal axis (27) of the fuel injector (27). [8] Burner (46) according to one of the preceding claims, characterized by that the wall element (9) blocks the opening cross-section of the combustion chamber (2) to a value which is between 60% and 80%. [9] Burner (46) according to one of the preceding claims, characterized by that the ratio of a length to a width of the primary chamber (2a) is between 1:1 and 1:

3. [10] Burner (46) according to one of the preceding claims, characterized by that the combustion chamber (2) runs in a straight line in a first combustion chamber section (2c) and in a second combustion chamber section (2d), wherein the courses in the first combustion chamber section (2c) and the second combustion chamber section (2d) are aligned at an angle to one another. [11] Burner (46) according to claim 10, characterized by that the first combustion chamber section (2c) comprises the primary chamber (2a) and a first section of the secondary chamber (2b). [12] Burner (46) according to one of the preceding claims, characterized by that the opening of the fresh gas guide (4) into the combustion chamber (2) is annular and surrounds the fuel outlet (30) of the fuel injector (5). [13] Burner (46) according to claim 12, characterized by that a (first) swirl element (11) for generating a swirl flow of the fresh gas is integrated into the mouth of the fresh gas guide (4) into the combustion chamber (2). [14] Burner (46) according to claim 13, characterized by a design of the fresh gas guide (4) such that the first swirl element (11) is flowed against axially by the fresh gas. [15] Burner (46) according to claim 13 or 14, characterized by a second swirl element (12) arranged upstream of the first swirl element (11).

Images