Combustion chamber wall and combustion chamber assembly for a heating device in a vehicle, as well as a method for manufacturing the same.

Description

Technical field:

[0001] The present invention relates to a combustion chamber wall and a combustion chamber assembly comprising this wall for a heating device in a vehicle, in particular for a heating device with vaporizing burner, the corresponding heating device and a method for manufacturing the combustion chamber assembly. Technical background:

[0002] Common combustion-based heating devices, such as those used in vehicles, including mobile air or water heaters, typically comprise a combustion chamber assembly that includes a combustion chamber housing. Within this housing, a combustion chamber is defined into which fuel is introduced, for example, by direct injection of fuel into the combustion chamber, by supplying a fuel-air mixture prepared outside the combustion chamber, or by supplying and subsequently vaporizing the fuel in a porous vaporizer, which may be heated for vaporization purposes. The combustion chamber may also contain an ignition element that initiates and, if necessary, maintains the combustion process.In particular, in the case of a separate supply of fuel and oxygen-containing gas, especially air, corresponding inlet openings may also be provided in a circumferential or bottom wall of the combustion chamber.

[0003] Similar heating devices, with forming sections in the circumferential wall for combustion air supply, are known from publications US 9 746 175 B2, US 10 571 119 B2, JP 2003 021322 A and DE 102 15 782 A1.

[0004] To achieve efficient, and especially low-emission, combustion in the combustion chamber, thorough mixing of gaseous fuel and atmospheric oxygen is desirable. The fuel can be introduced into the mixing zone in gaseous form or as an aerosol. This is often achieved by creating a swirl in the air flowing into the combustion chamber. Measures for this can include air guide elements located within the combustion chamber, perhaps near the inlet openings, but these significantly increase manufacturing costs and effort. Swirl can also be generated through other design features, such as axial / tangential swirl elements. These swirl elements are individual, sometimes complex, components that are positioned upstream of, integrated into, or part of the combustion chamber. Their complexity further increases costs and effort.

[0005] An alternative measure is to generate the swirl using tangentially oriented bores through the circumferential wall of the combustion chamber. However, this requires a minimum circumferential wall thickness of approximately the bore diameter, which in practice can lead to increased material usage and undesirable weight gain. Tangentially oriented bores cannot therefore be directly integrated into a thin-walled combustion chamber; instead, a separate, thick-walled component must generally be fabricated and implemented in the heating device.

[0006] Another way to generate swirl in the air-fuel mixture in the combustion chamber is by means of tabs pressed into the circumferential wall, e.g. by reshaping the wall material (engl. flapsThis can be achieved. This allows for the integration of swirl-generating inlet openings even in thin circumferential walls. In addition to such flaps, standard radially inward-facing bores (air inlet openings) can also be present.

[0007] Such a design for tab-like, pressed-in air inlet openings is known for the specific case of a combustion chamber assembly for a vaporizing burner. The air inlet openings are formed in the area of ​​respective gill-like projections on the circumferential wall. An air guide surface, formed by radial inward shaping, directs the air flowing in via an air supply chamber or a corresponding channel tangentially into the combustion chamber. In particular, each air inlet opening has an opening surface normal perpendicular to a radial line with respect to a longitudinal axis of the combustion chamber. In other words, the opening surface itself is perpendicular to the circumferential wall to achieve the tangential introduction of air into the combustion chamber.

[0008] However, this approach also has its drawbacks. Firstly, to offer an economically viable solution for forming such tabs, a pressing tool and a counter-stop are typically used. This requires the circumferential wall of the combustion chamber to be cut along a single line. As internal tests have shown, such a cutting process using a pressing tool does not correspond to a proper cutting operation, but rather to tearing the material along this line.

[0009] When the tool is new, this separation process yields satisfactory results regarding the quality of the separation line and the two resulting radially separated edge sections. However, with progressive tool wear, burrs increasingly form, oriented in such a way that they reduce the cross-sectional area through which the fluid flows, thus significantly and adversely affecting the combustion conditions. To prevent this loss of quality, every circumferential wall or every manufactured combustion chamber assembly with this circumferential wall should be inspected for burrs after the manufacturing process. This could be achieved, for example, by...This can be done using a pressure loss test bench, but this significantly increases manufacturing costs and production time, not to mention that the tools in question may no longer be usable at an early stage of their actual service life.

[0010] As internal tests have also shown, a further disadvantage of the approach described above is that the tangentially oriented opening area of ​​the inlet opening initially causes the introduced air to flow directly along the circumferential wall. Due to the well-known Coandé effect, this flow then remains along the circumferential wall for an extended period in a radially outer region of the combustion chamber. Consequently, the desired swirl is only generated in the radially outer region of the combustion chamber and decreases sharply towards its longitudinal or central axis. As a result, sufficient mixing within the combustion chamber is limited. The goal, however, is to generate the swirl as homogeneously as possible along the radial direction. Presentation of aspects of the invention

[0011] It is therefore a task to improve the swirl imparted to a combustion chamber of a combustion chamber assembly, in particular to improve the mixing of a fuel with a suitable oxidizer such as oxygen in the air, while at the same time limiting costs and effort in manufacturing.

[0012] One aspect of the invention relates to a combustion chamber wall for a combustion chamber assembly or for a heating device in a vehicle, comprising a cylindrical circumferential wall that defines a central axis extending in the axial direction and forms a combustion chamber. At least one structure for introducing an oxidizer into the combustion chamber is formed in the circumferential wall. This structure comprises a relief formed in the circumferential wall, which forms an inlet opening, and a formed section in the circumferential wall, which is shaped in a radial direction towards the central axis. The relief is directly adjacent to the formed section shaped towards the central axis in a circumferential direction of the circumferential wall.

[0013] The vehicle in question may be a motor vehicle, a trailer or caravan, a motorhome, a construction machine or even an aircraft or watercraft, etc., and the term "vehicle" is to be interpreted broadly.

[0014] The proposed combustion chamber wall, with its structure for introducing an oxidizer into the combustion chamber, offers advantages in both manufacturing and fluid mechanics. In particular, the inclusion of the relief cut leads to a surprising synergy effect: the relief cut can, for example, be created in the first process step of the corresponding manufacturing process within the material of the circumferential wall. The relief cut involves removing a flat section of material from the circumferential wall, resulting in the formation of a hole. This process can advantageously be a punching process. Here, the material is separated by shearing. Burr formation is negligible in this process.

[0015] This process can also be carried out in conjunction with perforating the combustion chamber, creating a number of smaller (radially oriented) inlet openings for introducing the oxidizer. Punching the inlet therefore represents hardly any additional effort. However, alternative laser cutting or another easily automated method for creating the inlet is also possible. Here, too, burr formation may be negligible or not expected at all.

[0016] Once the relief cut is formed, the forming section can be produced in the circumferential wall. The forming process can be applied locally to a section of the circumferential wall material that includes at least one ("second") edge section of the relief cut, which, in the assembled state, faces the circumferential direction of the wall. Thus, when forming radially towards the central axis, the conventional "tearing" of the wall material to create the entry opening is eliminated. This also eliminates burr formation. The opening surface of the entry opening can now be precisely and burr-free during manufacturing.

[0017] The free-cutting process can thus be manufactured particularly economically and reliably. The risk of burrs extending into the flow area of ​​the inlet opening is completely eliminated. Therefore, a subsequent inspection process is also unnecessary. Furthermore, it is possible to use a thin-walled material to generate a tangentially directed swirl, which reduces costs, effort, and weight.

[0018] The aforementioned synergy effect arises from the additional benefit of improved flow characteristics of the oxidizer introduced into the combustion chamber. The geometry of the inlet opening formed by the free-cut and forming section is determined by the dimensions of the free-cut, particularly its circumferential length, and the drawing depth of the forming section directed towards the central axis. The first and second edge sections of the free-cut, which are opposite each other circumferentially, can thus be spaced apart circumferentially by the free-cut itself and also radially by the forming section.

[0019] The inflow angle and the flow area can therefore be adjusted by the drawing depth on one (second) edge section of the relief cut – or, according to exemplary embodiments, on both edge sections. The same applies to the selected length of the relief cut in the circumferential direction. This design thus allows, according to exemplary embodiments, the generation of a radial velocity component in addition to a tangential one. A purely tangential orientation of the flow area is not possible with this relief cut – it would then have a vanishing length in the circumferential direction when viewed from above (from the outside along the radial direction), i.e., it would be non-existent, which would correspond to the prior art described above.

[0020] Due to the additional radial component of the flow – alongside the tangential component – ​​the Coandé effect no longer occurs, as the flow is not bound to the combustion chamber wall. Instead, a homogeneous swirl flow is generated across the entire combustion chamber cross-section, resulting in good mixing.

[0021] As described, the relief cut forming the inlet opening adjoins the forming section, which is shaped towards the central axis, in a circumferential direction along the perimeter wall. The relief cut can be defined by its opposing edge sections in the circumferential direction (as well as axially oriented end-face sections). The radial inward forming of the forming section, which encompasses the second edge section, over-forms the relief cut, but it remains a relief cut. The direct adjoining therefore refers to the fact that the second edge section of the relief cut is part of the forming section and faces the circumferential direction of the perimeter wall, so that the inlet opening formed by the relief cut extends circumferentially from the radially indented forming section.This does not expressly preclude the forming section from encompassing the relief cut, as provided for in a special embodiment described below. Here, the inlet opening is located on a flank of the forming section in the circumferential direction, but the relief cut, through its second edge section on this flank, still connects to the forming section in the circumferential direction.

[0022] The oxidizer usable with the combustion chamber wall or combustion chamber assembly can be air, or pure oxygen, or another oxygen compound suitable for oxidizing the fuel. The fuel can be diesel or gasoline. Kerosene, hydrogen, or other fuels are also possible. The aspects of the invention are not limited to specific substances with regard to fuel and oxidizer.

[0023] The circumferential wall is cylindrical. The circumferential wall can be a section of a wall component that has several sections, e.g., a flange, a section tapering conically towards the flame tube, and / or the flame tube itself, etc.

[0024] In the combustion chamber assembly, a bottom section and the wall component can be permanently connected, e.g., welded. The bottom section can include an evaporator receptacle and, for example, a porous evaporator, to which the fuel is supplied for vaporization in a known manner. An, for example, electric heating device can assist the vaporization process. Alternatively, the fuel can also be injected via a nozzle arranged in the bottom section. Furthermore, the bottom section can instead have a feed line for a prepared fuel-oxidizer mixture. The invention is not limited to specific embodiments of the bottom section, and further configurations are possible.

[0025] The combustion chamber assembly, formed by the combustion chamber wall, may also include an ignition element located at least partially within the combustion chamber, which can be used to initiate and / or maintain a combustion process. Flame baffles may also be optionally incorporated into the combustion chamber.

[0026] It should be noted that one embodiment of a combustion chamber assembly is fundamentally encompassed by the invention in which a forming process takes place first during manufacturing, followed by the removal of material to form the relief cut. The burrs that arise at the tear edge during the forming process are removed during the subsequent punching or cutting with the tear edge (provided the drawing die still allows for this structure), leaving only the corresponding second edge section of the relief cut.

[0027] Advantageous further developments and embodiments are described below, some of which are also reflected in the attached dependent claims. Some of these have already been outlined above.

[0028] The free-flowing section can be defined, for example, by the first and second edge segments, already indicated above, which are opposite each other and spaced apart circumferentially. The second edge segment is part of the section of the circumferential wall shaped towards the central axis. In this case, the first edge segment can be located further away from the central axis than the second edge segment. This creates a swirling flow with a radially inward-directed component, resulting in improved mixing and preventing the Coandé effect.

[0029] Another embodiment provides that the inlet opening forms an opening surface with a surface normal corresponding to a flow vector of the oxidizer passing through the inlet opening, wherein the surface normal has a radial component in the radial direction and a tangential component in the circumferential direction with respect to the central axis of the circumferential wall in order to generate a swirl in the combustion chamber in the case of an oxidizer flow introduced through the inlet opening.

[0030] A specific further development of the combustion chamber wall provides that at least two, preferably four or more, structures for introducing an oxidizer into the combustion chamber are arranged in the circumferential wall. A higher number of structures for introducing an oxidizer into the combustion chamber allows for improved fine-tuning of the homogeneity of the mixing, given the radial component in the flow, and avoids vibrations / frequencies during the combustion process. It is advantageous to distribute several flaps (more than two) around the circumference, thereby reducing the size of secondary vortices and their influence on combustion.

[0031] According to one embodiment, the structures for introducing an oxidizer into the combustion chamber are arranged in the circumferential wall at an equal distance from the bottom section to be attached at the front or from a surface of an evaporator arranged therein. This arrangement ensures a homogeneous swirl and thus homogeneous mixing of the introduced oxidizer with the fuel-gas mixture in the combustion chamber.

[0032] According to another embodiment, the structures for introducing an oxidizer into the combustion chamber can be arranged successively in the circumferential wall at equal intervals. The effect is similar to that described with reference to the previous embodiment.

[0033] According to embodiments, the circumferential wall of the combustion chamber can be formed from a metal, preferably a steel sheet comprising a steel alloy. In this case, the formed section of the circumferential wall can be deep-drawn in a radial direction towards the central axis. The advantages have already been explained above.

[0034] Furthermore, the free-cut area can be formed by punching or cutting out, and removing an initial section from the circumferential wall. This has already been mentioned above.

[0035] According to embodiments of the combustion chamber assembly, the combustion chamber can be connected via the inlet opening to an oxidizer feed chamber or an oxidizer feed channel surrounding the circumferential wall.

[0036] According to exemplary embodiments, the forming section can have a convexly curved shape that breaks off in the circumferential direction at the second edge section towards the relief cut. The forming section thus takes the form of a pressed-in tab, but with, among other things, a relief cut that is offset or positioned in front of it in the circumferential direction.

[0037] According to a further embodiment, the forming section of the combustion chamber wall can be essentially symmetrical with respect to an axis extending tangentially or circumferentially. Minor deviations from symmetry that do not affect the flow direction of the oxidizer passing through the inlet opening are negligible. In this embodiment, the forming section has a first length along this axis up to the second edge section that is greater than the second length of the clearance between the first edge cut and the second edge section along this axis. This prevents an excessively strong radial component of the flow that could impair the swirl.

[0038] According to a further embodiment, the formed section of the combustion chamber wall can have a drawing depth in the radial direction, achieved through a forming process. This depth—optionally in conjunction with a relatively small thickness of the material in the formed section—results in a radially outward-facing surface of the formed section adjacent to the second edge section being positioned closer to the central axis by a different distance than a radially inward-facing surface of the surrounding wall adjacent to the first edge section. This measure allows the radial component of the flow direction through the inlet opening to be adjusted.

[0039] Here, the distance difference can optionally be less than a second length of the free section between the first edge section and the second edge section along an axis extending in a tangential direction. This avoids an overly dominant tangential component of the flow, which could lead to the Coandé effect.

[0040] According to a specific embodiment mentioned above, in addition to the actual forming section, a region of the circumferential wall adjacent to the first edge section can also be formed radially towards the central axis. In principle, the forming section can thus extend around the cut-out with its circumferentially oriented flank. Preferably, the condition that the second edge section has a smaller distance to the central axis of the circumferential wall than the first edge section is retained in order to generate the radial component of the flow direction of the oxidizer flowing through the inlet opening. A particular advantage of this embodiment arises from the fact that the inlet opening itself, with its radially outermost first edge section, is raised (i.e., offset towards the central axis) in the inwardly facing surface of the circumferential wall.The flow enters the combustion chamber through the inlet opening at a distance from this combustion chamber wall, and the Coandé effect is thereby further suppressed.

[0041] Aspects of the invention also relate to a combustion chamber assembly comprising the combustion chamber wall according to one of the above aspects or embodiments, further comprising a bottom section, wherein the bottom section and the cylindrical circumferential wall form a combustion chamber housing and define the combustion chamber therein, and wherein the bottom section is arranged to supply fuel to the combustion chamber.

[0042] Aspects of the invention also relate to a heating device comprising the described combustion chamber assembly with the combustion chamber wall. The heating device can provide a heat exchanger and corresponding inlet and outlet lines for the medium to be heated (cooling medium). This medium can be, for example, air or water. The heating device can, in particular, be an air heater (English: air heater). air heater ). In this case, the heating device may additionally include a hot air blower with motor, corresponding control device and electrical power source.

[0043] Aspects of the invention also relate to a method for manufacturing the combustion chamber wall, comprising: Providing a material for the circumferential wall; punching or cutting out a first section from the material of the circumferential wall to form the relief cut; subsequently forming, preferably deep drawing, a second section in the material of the circumferential wall to form the forming section, wherein the relief cut is directly adjacent to the forming section.

[0044] The advantages are the same as described above. Brief description of the drawings:

[0045] The invention described above will now be explained by way of example with reference to the accompanying drawings and a preferred embodiment.

[0046] They show: Figure 1 shows a schematic sketch of a cross-section of a combustion-based heating device according to an exemplary embodiment; Figure 2 shows a side view of a circumferential wall component of the heating device. Fig. 1 Figure 3 Fig. 2 , but in perspective view; Figure 4 a cross-sectional view of the perimeter wall component made of Fig. 2 along its central axis in the direction of the flange-side end; Figure 5 as above Fig. 4 , but towards the end on the flame tube side; Figure 6 in top view and enlarged one of the in the Fig. 1 - 5 Structures shown for introducing an oxidizer into the combustion chamber; Figure 7 Fig. 6 , but in cross-sectional view along line AA; Figure 8 the same top view as in Fig. 6 , but with illustrated lengths and widths of the free section and forming section; Figure 9, the same top view as in Fig. 7 , but with illustration of the surface normal of the opening plane or the flow direction with directional components; Figure 10 Top view as in Figure 6 , but for a modified embodiment; Figure 11 cross-sectional view as in Fig. 7 , but for the modified embodiment from Fig. 10 , along line BB. Detailed description of preferred embodiments:

[0047] In the following description of preferred embodiments, it should be noted that the present disclosure of the various aspects is not limited to the details of the construction and arrangement of the components as illustrated in the following description and in the figures. All embodiments, including those not shown in the figures, can be implemented or carried out in practice in various ways. Furthermore, it should be noted that the language and terminology used here are employed solely for the purpose of concrete description and should not be interpreted restrictively by those skilled in the art.Furthermore, in the following description, identical reference symbols in the figures denote identical or similar features or objects, so that in some cases a repeated detailed description of the same is omitted in order to preserve the compactness and clarity of the presentation.

[0048] In the Fig. 1A schematic sketch shows a cross-section of a combustion-based heating device 1 according to an exemplary embodiment. The heating device 1 comprises a combustion chamber assembly 100 and a heat exchanger 200. The combustion chamber assembly 100 comprises a combustion chamber 8, an evaporator receptacle 10, and an evaporator element 12 for vaporizing a liquid fuel. The combustion chamber 8, the evaporator receptacle 10, and the evaporator element 12 are designed to be essentially rotationally symmetrical. The combustion chamber 8 is bounded circumferentially by a circumferential wall component 14, in particular by a thin-walled circumferential wall 44 (see Figure 1). Fig. 2), which represents a cylindrical-shaped section of the circumferential wall component 14 and has a cylindrical, longitudinal, or central axis C. At its end face, the combustion chamber 8 is bounded by the evaporator receptacle 10 in the fuel supply area, which includes a fuel supply pipe 36. The evaporator element 12 is accommodated in the evaporator receptacle 10 on the side facing the combustion chamber 8.

[0049] The combustion chamber assembly 100 also includes, on the side of the evaporator receptacle 10 facing away from the combustion chamber 8, a cap-like guide element for supplying the oxidizer, e.g., combustion air. The guide element 16 is fitted over the evaporator receptacle 10. An oxidizer supply chamber 20 is formed in an annular shape around the combustion chamber 8. A gap 18 between the evaporator receptacle 10 and the guide element 16 opens into the oxidizer supply chamber 20. From the oxidizer supply chamber 20, a fluid connection is established with the combustion chamber 8 via inlet openings of structures 22 for introducing an oxidizer into the combustion chamber, which are formed in the thin-walled circumferential wall 44 of the circumferential wall component 14. The structures 22 are described in greater detail below. The circumferential wall with the structures incorporated therein represents an embodiment of a combustion chamber wall according to the invention.

[0050] The fuel supply line 36 is arranged within an oxidizer supply line 24, which directs the oxidizer to the gap 18, so that it is cooled by the flow around the oxidizer during operation. A first flow path 142 for the exhaust gases is formed in the heat exchanger 200. The exhaust gases flow within the heat exchanger 200 along the first flow path 142 to an exhaust gas outlet 144, through which the exhaust gases are discharged to the outside. Furthermore, a second flow path 146 is provided within the heat exchanger 200, in which the vehicle's cooling fluid, e.g., air, is guided. The first 142 and the second 146 flow paths are arranged such that heat is effectively transferred from the exhaust gases to the cooling fluid during operation.

[0051] The in Fig. 1 The perimeter wall component 14 shown is described in greater detail in the Figs. 2 to 5 shown. The Figures 2 and 3The figures show the perimeter wall component 14 in side and perspective views, while the Figures 4 and 5 Views along the central axis C in the direction of the flange-side end and the flame tube-side end are shown. The circumferential wall component 14 essentially comprises four sections: a flange 40, with which the circumferential wall component 14 can be connected to the bottom section 26; the essentially cylindrical circumferential wall 44; a chronically tapered section 46; and a flame tube section 48.

[0052] The thin-walled circumferential wall component 14 is made in one piece and preferably from a stainless steel alloy with a wall thickness d of 1 mm (see Fig. 7The inner diameter of the circumferential wall 44, which defines the combustion chamber 8 within the interior, can be, for example, 45 mm in the case of an air heater with a power output of 1–5 kW. In the case of an air duct with a power output of 5–15 kW, the inner diameter can be 70 mm.

[0053] Where - as in Fig. 1 As can be seen, the oxidizer feed chamber 20 extends around the circumferential wall 44 (ring-shaped) as a pre-chamber, and the structures 22 for supplying the oxidizer to the combustion chamber 8 as well as a multitude of smaller, radially directed inlet openings 42 are formed in the circumferential wall 44.

[0054] The structures 22 are arranged circumferentially at equal intervals to each other in the circumferential direction P and at equal intervals in the axial direction X to the flange 40 and to the bottom section 26, respectively. In the Figures 4 and 5It can be seen that four of the structures 22 are formed. The structures 22 comprise a relief section 52 and a forming section 54. The relief section 52 is arranged circumferentially P behind the forming section 54 and adjoins it directly. The relief section 52 and the forming section 54 are continuous. The relief section 52 forms a larger inlet opening compared to the radially oriented inlet openings 42. The oxidizer feed chamber 20 is in fluid communication with the combustion chamber 8 via the inlet openings 42 and the respective relief sections 52, which serve as inlet openings for the structures 22.

[0055] In the Figures 2 - 5The cylindrical coordinate system used here for the description, with axial direction X, radial direction R, and circumferential direction P, is also shown in particular. The circumferential wall 44 also has a radially inward-facing surface 441 and a radially outward-facing surface 442. A tangential direction T is also locally defined in the circumferential wall, see [reference]. Fig. 5 .

[0056] The Figs. 6 and 7 show in top view ( Fig. 6 ) from the outside or in cross-sectional view ( Fig. 7 ) the structures 22 for introducing an oxidizer into the combustion chamber 8 in greater detail.

[0057] As described, the structure 22 comprises a forming section 54 and a free-cut section 52. Figure 6The circumferential direction P is oriented parallel to the line AA to the left. The relief section 52 adjoins the forming section 54 directly in the circumferential direction P. The relief section 52 has an axial direction X (direction from bottom to top). Figure 6 The elongated shape has two edge sections 60 and 62 opposite each other in the circumferential direction P. The first edge section 60 is formed in the flat, unformed circumferential wall 44 and faces the formed section 54, while the second edge section 62 points in the circumferential direction P. In this embodiment, the edge sections 60 and 62 are parallel to each other. The clearance 52 is formed by removing material from the circumferential wall 44, e.g., in a stamping process together with the formation of the inlet openings 42, or by laser cutting, etc.

[0058] The forming section 54 is - like the free section 52 - mirror-symmetrical to an axis directed in the tangential direction T (corresponds to the line AA in Fig. 6 The forming section 54 is formed in the radial direction R towards the central axis C, in particular by a deep drawing process with a drawing depth z, see Fig. 7 The deep-drawing die used for this process creates a convex shape for the forming section 54, curved radially towards the central axis C. This shape gives the forming section 54 the form of a tab because the forming section 54 breaks off in the circumferential direction P at the second edge section 62 towards the relief cut 52. As in Figure 7 As can be seen, the first edge section 60 is opposite the second edge section 62 in the circumferential direction P, however, due to the drawing depth z, the second edge section 62 is positioned closer to the central axis C in the radial direction R than the first edge section 60.

[0059] In particular, an outwardly facing surface 443 adjacent to the second edge section 62 and the inwardly facing surface 441 of the circumferential wall 44 adjacent to the first edge section 60 form a distance difference s with respect to their distance to the central axis C, which in the exemplary embodiment is 0.5 mm. The drawing depth z is 1.5 mm and the wall thickness d is 1 mm in the exemplary embodiment.

[0060] This choice of dimensions creates an inclined opening surface plane O for the inlet opening formed by the free-cut 52, as shown in the Fig. 7 analog Fig. 9The surface normal N, which ideally corresponds to the flow direction of the oxidizer flowing through the inlet openings, consequently has a tangential component NT and a radial component NR. The tangential component NT thus generates a swirl in the combustion chamber 8, while the radial component NR prevents the Coandé effect and distributes the flow rate homogeneously in the radial profile, thereby improving mixing.

[0061] In Figure 8 are in the Figure 6 The analogous top view of structure 22 shows the length and width ratios for the relief section 52 and the forming section 54. Length is considered here in the circumferential direction P, and width in the axial direction X. In this view, the relief section 52 is almost twice as wide as it is long. The width w1 is 5.4 mm, and the length l1 is 2 mm.

[0062] The width w2 of the forming section 54, in this specific embodiment which does not limit the generality of the invention, is also 5.4 mm or slightly more, since it tapers laterally in the axial direction X, as can be seen in Figure eight. The length l2 of the forming section 54 along the axis (line AA in Fig. 6 The circumferential dimension is also 5.4 mm up to the second edge section 62. On both sides in the axial direction X, the forming section 54 also encompasses the relief cut 52, as shown by the Fig. 6 and 8 The forming section 54 is therefore longer than the free cut 52, while the widths w1, w2 are approximately comparable.

[0063] The specifications refer to an air heater with a power output of 1-5 kW, where the inner diameter of the circumferential wall is 45 mm. For the air heater with a power output of 5-15 kW, with an inner diameter of 70 mm, the dimensions are approximately twice as large.

[0064] The dimensions specified above may be chosen differently, either individually or in their entirety, in modified embodiments.

[0065] A further modified embodiment is described in the Figures 10 and 11 shown. The forming section 54 is supplemented here by an extended forming section 56, with which the relief 52 is encompassed by the forming of the circumferential wall 44 inwards towards the central axis C. As shown in Figure 11 As can be seen, the first edge section 60 is also formed in the radial direction R towards the central axis C. Overall, this measure shifts the relief 52, or rather the inlet opening of the structure 22 formed by it, towards the central axis, so that it is raised above the surrounding, inwardly facing surface 441 of the circumferential wall 44. This also prevents the Coandé effect.

[0066] The features of the invention disclosed in the foregoing description, in the drawings and in the claims may be essential for the realization of the invention, both individually and in any combination. Reference symbol list

[0067] 1 Heating device 8 Combustion chamber 10 Evaporator receptacle 12 Evaporator element 14 Circumferential wall for combustion chamber 16 Oxidizer guide element 18 Gap 20 Oxidizer feed chamber 22 Structure for introducing an oxidizer into the combustion chamber 24 Oxidizer feed line 26 Bottom section 30 Side wall of the bottom section 32 Ignition device 36 Fuel feed line 40 Flange 42 Radially directed, smaller inlet openings 44 Circumferential wall 46 Conical section 48 Flame tube section 52 Free cut 54 Forming section 56 Extension of the forming section 60 First edge section 62 Second edge cut 100 Combustion chamber assembly 142 First flow path 144 Exhaust gas discharge 146 Second flow path 200 Heat exchanger 441 Inward-facing surface of the circumferential wall 442 Outward-facing surface of the circumferential wall C Mid-axis, cylinder axis, longitudinal axis of the circumferential wall X Axial direction R Radial direction P Circumferential direction T Tangential direction (in structure 22) d Wall thickness s Spacing difference z Draw depth

Claims

1. Combustion-chamber wall for a combustion-chamber assembly (100) of a heating device (1) in a vehicle, wherein the combustion-chamber wall is configured to form a combustion chamber (8), comprising: a cylindrical circumferential wall (44) which defines a central axis (C) extending in an axial direction (X); wherein at least one structure (22) for introducing an oxidant into the combustion chamber (8) is formed in the circumferential wall (44), wherein the structure comprises a deformation portion (54) formed in the circumferential wall (44) that is formed towards the central axis (C) in a radial direction (R); characterized in that the structure further comprises: - a cutout (52) formed in the circumferential wall that forms an introduction opening; - wherein the cutout (52) directly adjoins the deformation portion (52), formed towards the central axis (C), in a circumferential direction (P) of the circumferential wall (44).

2. Combustion-chamber wall according to Claim 1, wherein the cutout (52) is defined by mutually oppositely situated first and second edge portions (60, 62) which are spaced apart from one another in the circumferential direction (P); the second edge portion (62) is part of the deformation portion (54) of the circumferential wall (44) formed towards the central axis (C); and the first edge portion (60) is at a greater distance from the central axis than the second edge portion (62).

3. Combustion-chamber wall according to Claim 1 or 2, wherein the introduction opening forms an opening surface (O) with a surface normal (N) corresponding to a flow vector of the oxidant that passes through the introduction opening; and the surface normal (N), in relation to the central axis (C) of the circumferential wall (44), has a radial component (NR) in the radial direction (R) and has a tangential component (NT) in the circumferential direction (P) so as, in the case of an oxidant stream introduced through the introduction opening, to generate swirl in the combustion chamber (8).

4. Combustion-chamber wall according to one of Claims 1 to 3, wherein at least two, preferably four, of the structures (22) for introducing an oxidant into the combustion chamber (8) are arranged in the circumferential wall (44).

5. Combustion-chamber wall according to Claim 4, wherein the structures (22) for introducing an oxidant into the combustion chamber (8): - are arranged in the circumferential wall (44) at an equal distance from a base portion (26) which is to be connected at an end face to the circumferential wall, or from a surface of an evaporator arranged in said base portion; and / or - are arranged in the circumferential wall (44) at equal distances from one another so as to follow one another in the circumferential direction (P).

6. Combustion-chamber wall according to one of Claims 1 to 5, wherein the circumferential wall (44) is formed from a metal, preferably a steel sheet comprising a steel alloy; and the deformation portion (54) of the circumferential wall (44) is formed by deep drawing towards the central axis (C) in the radial direction (R).

7. Combustion-chamber wall according to one of Claims 1 to 6, wherein the cutout (52) is formed by punching out, or cutting out, and removing a first portion from the circumferential wall (44).

8. Combustion-chamber wall according to one of Claims 1 to 7, wherein the combustion chamber (8) is connected via the introduction opening to an oxidant supply chamber (20) surrounding the circumferential wall (44) or to an oxidant supply channel.

9. Combustion-chamber wall according to one of Claims 1 to 8, wherein the deformation portion (54) has a convexly curved shape which terminates at the second edge portion (62) in the circumferential direction (P).

10. Combustion-chamber wall according to one of Claims 1 to 9, wherein the deformation portion (54) is of substantially symmetrical form in relation to an axis (AA, BB) extending in a tangential direction (T) and has a first length (12) along this axis as far as the second edge portion (62) that is greater than a second length (11) of the cutout (52) between the first edge portion (60) and the second edge portion (62) along this axis.

11. Combustion-chamber wall according to one of Claims 1 to 10, wherein the deformation portion (54), in relation to the radial direction (R), has a drawing depth (z) effected by a deformation process that results in a radially outwardly facing surface (443) of the deformation portion adjacent to the second edge portion (62) being positioned closer to the central axis (C) than a radially inwardly facing surface (441) of the circumferential wall (44) adjacent to the first edge portion (60) by a difference in distance (s).

12. Combustion-chamber wall according to Claim 11, wherein the difference in distance (s) is less than a second length (i1) of the cutout between the first edge portion (60) and the second edge portion (62) along an axis (AA, BB) extending in the tangential direction (T).

13. Combustion-chamber wall according to one of Claims 1 to 12, wherein additionally, a region of the circumferential wall (44) adjacent to the first edge portion (60) is formed towards the central axis (C) in the radial direction (R); and / or a plurality of radially directed introduction openings (42) for introduction of the oxidant that are smaller in relation to the cutout is formed in the circumferential wall (44).

14. Combustion-chamber assembly (100) comprising the combustion-chamber wall according to one of Claims 1 to 13, further comprising a base portion (26), wherein the base portion (26) and the cylindrical circumferential wall (44) form a combustion-chamber housing and, therein, define the combustion chamber (8), and wherein the base portion (26) is configured to supply a fuel to the combustion chamber (8).

15. Heating device (1) for a vehicle, comprising the combustion-chamber assembly (100) according to Claim 14.

16. Method for producing a combustion-chamber wall according to one of Claims 1 to 13, comprising: - providing a circumferential wall; - punching out or cutting out a first portion from the material of the circumferential wall to form the cutout; - deforming, preferably deep drawing, a second portion in the material of the circumferential wall to form the deformation portion, wherein the cutout directly adjoins the deformation portion.