COMBUSTION CHAMBER WALL AND COMBUSTION CHAMBER ASSEMBLY FOR A HEATING DEVICE IN A VEHICLE AND PROCESS FOR THEIR PRODUCTION

Abstract

A combustion chamber wall for a combustion chamber assembly (100) of a heating device (1) in a vehicle is arranged to form a combustion chamber (8). It comprises a cylindrical circumferential wall (44), which defines a central axis (C) extending in the axial direction (X). At least one structure (22) for introducing an oxidizer into the combustion chamber (8) is formed in the circumferential wall (44). The structure comprises a cutout recess (52) formed in the circumferential wall, which forms an introduction opening, and a worked section (54) formed in the circumferential wall (44), which is deformed in a radial direction (R) towards the central axis (C). In a circumferential direction (P) of the circumferential wall (44), the cutout recess (52) directly adjoins the worked section (52) which is deformed towards the central axis (C).

Claims

1. A combustion chamber wall for a combustion chamber assembly of a heater in a vehicle, the combustion chamber wall being configured to define a combustion chamber comprising: a cylindrical circumferential wall, which defines a central axis extending in the axial direction; wherein at least one structure for introducing an oxidizer into the combustion chamber is formed in the circumferential wall, the structure comprising: a cutout recess formed in the circumferential wall, which forms an inlet opening; and a worked section formed in the circumferential wall, which is deformed in a radial direction inwards towards the central axis; wherein the cutout recess adjacently adjoins the worked section, that is deformed towards the central axis, in a circumferential direction of the circumferential wall.

2. The combustion chamber wall according to claim 1, wherein the cutout recess is defined by first and second edge sections which are opposite one another and spaced apart from one another in the circumferential direction; the second edge portion is part of the worked section of the circumferential wall deformed towards the central axis; and the first edge section has a greater distance from the central axis than the second edge section.

3. The combustion chamber wall according to claim 1, wherein the inlet opening forms an opening surface with a surface normal corresponding to a flow vector of the oxidizer passing through the inlet opening; and the surface normal has a radial component in the radial direction in relation to the central axis of the circumferential wall and a tangential component in the circumferential direction configured to generate a swirl in the combustion chamber in the event of an oxidizer flow introduced through the inlet opening.

4. The combustion chamber wall according to claim 1, wherein at least two of the structures for introducing an oxidizer into the combustion chamber are arranged in the circumferential wall.

5. The combustion chamber wall according to claim 4, wherein the structures for introducing an oxidizer into the combustion chamber: are arranged in the circumferential wall at an equal distance from a base section to be connected at an end face to the circumferential wall or a surface of an evaporator arranged therein; and/or are arranged consecutively in the circumferential wall in the circumferential direction at equal distances from one another.

6. The combustion chamber wall according to claim 1, wherein the circumferential wall is formed of a metal; and the worked section of the circumferential wall is formed by deep drawing in the radial direction toward the central axis.

7. The combustion chamber wall according to claim 1, wherein the cutout recess is formed by punching or cutting out and removing a first section from the circumferential wall.

8. The combustion chamber wall according to claim 1, wherein the combustion chamber is connected via the inlet opening to an oxidizer supply chamber surrounding the circumferential wall or to an oxidizer supply channel.

9. The combustion chamber wall according to claim 1, wherein the worked section has a convexly curved shape which terminates in the circumferential direction by the second edge section.

10. The combustion chamber wall according to claim 1, wherein the worked section is substantially symmetrical with respect to an axis extending in the tangential direction and has a first length along this axis up to the second edge section, which is greater than a second length of the cutout recess between the first edge section and the second edge section along this axis.

11. The combustion chamber wall according to claim 1, wherein the worked section has a drawing depth with respect to the radial direction caused by a deformation process, which results in a radially outwardly facing surface of the forming portion adjacent to the second edge portion being positioned closer to the central axis by a difference in respective distances than a radially inwardly facing surface of the circumferential wall adjacent to the first edge portion.

12. The combustion chamber wall according to claim 11, wherein the difference in respective distances is less than a second length of the cutout recess between the first edge section and the second edge section along an axis extending in the tangential direction.

13. The combustion chamber wall according to claim 1, wherein in addition, a region of the circumferential wall adjacent to the first edge portion is deformed towards the central axis in the radial direction; and/or a plurality of radially directed inlet openings, which are smaller in relation to the cutout recess, are formed in the circumferential wall for introducing the oxidizer.

14. The combustion chamber assembly comprising the combustion chamber wall according to claim 1, further comprising a base section, wherein the base section and the cylindrical circumferential wall form a combustion chamber housing and define the combustion chamber therein, and wherein the base section is adapted to supply a fuel to the combustion chamber.

15. A heating device for a vehicle, comprising the combustion chamber assembly according to claim 14.

16. A method of manufacturing a combustion chamber wall according to claim 1, comprising: providing a circumferential wall; punching or cutting out a first section from the material of the circumferential wall to form the cutout recess; working a second section in the material of the circumferential wall to form the worked section, whereby the cutout recess adjacently adjoins the worked section.

17. The combustion chamber wall according to claim 4, wherein four of the structures for introducing an oxidizer into the combustion chamber are arranged in the circumferential wall.

18. The combustion chamber wall according to claim 6, wherein the metal, comprises a steel sheet comprising a steel alloy.

19. The method of claim 16, wherein the step of working comprises deep drawing a second section in the material of the circumferential wall.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0047] The invention described above will now be explained by way of o preferred embodiment with reference to the accompanying drawings.

[0048] Therein:

[0049] FIG. 1 shows a schematic illustration of a cross-section of a heating device based on combustion technology according to an embodiment;

[0050] FIG. 2 shows a side view of a circumferential wall component of the heating device depicted in FIG. 1;

[0051] FIG. 3 shows the same as FIG. 2, but in a perspective view;

[0052] FIG. 4 shows a cross-sectional view of the circumferential wall component shown in FIG. 2 along its central axis in the direction of the flange-side end;

[0053] FIG. 5 shows the same as FIG. 4, but in the direction of the end on the flame tube side;

[0054] FIG. 6 shows a top view and an enlarged view of one of the structures shown in FIGS. 1-5 for introducing an oxidizer into the combustion chamber;

[0055] FIG. 7 shows the same as FIG. 6, but in cross-sectional view along line AA;

[0056] FIG. 8 shows the same top view as in FIG. 6, but with illustrated lengths and widths of the cutout recess and the worked section;

[0057] FIG. 9 shows the same top view as in FIG. 7, but with an illustration of the surface normals of the opening plane or the flow direction with directional components;

[0058] FIG. 10 shows a top view such as in FIG. 6, but for a modified embodiment;

[0059] FIG. 11 shows a cross-sectional view as depicted in FIG. 7, but for the modified embodiment of FIG. 10, along line BB.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

[0060] 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 structure and arrangement of the components as shown in the following description and in the figures. All embodiments, including those not shown in the figures, can be put into practice or implemented in various ways. It should also be noted that the expressions and terminology used herein are for the purpose of specific description only and should not be construed as such in a limiting manner by the skilled person. Furthermore, in the following description, identical reference signs in the figures designate identical or similar features or objects, so that in some cases a repeated detailed description of the same is dispensed with in order to preserve the compactness and clarity of the description.

[0061] FIG. 1 shows a schematic sketch of a cross-section of a heating device 1 based on combustion technology according to an 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 evaporating a liquid fuel. The combustion chamber 8, the evaporator receptacle 10 and the evaporator element 12 are essentially rotationally symmetrical. The combustion chamber 8 is bounded in the circumferential direction by a circumferential wall component 14, in particular by a thin-walled circumferential wall 44 (see FIG. 2), which represents a cylindrical section of the circumferential wall component 14 and has a cylindrical, longitudinal or central axis C. At the front, the combustion chamber 8 is bounded by the evaporator receptacle 10 in the region of the fuel supply, which comprises a fuel supply tube 36. The evaporator element 12 is accommodated in the evaporator receptacle 10 on the side facing the combustion chamber 8.

[0062] The combustion chamber assembly 100 also comprises a cap-like guide element 16 on the side of the evaporator receptacle 10 facing away from the combustion chamber 8 for guiding or supplying the oxidizer, e.g. combustion air. The guide element 16 is placed over the evaporator receptacle 10. An oxidizer supply chamber 20 is formed in a ring 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 with the combustion chamber 8 is in turn established 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 44 with structures incorporated therein represents an embodiment of a combustion chamber wall according to the invention.

[0063] The fuel supply tube 36 is arranged within an oxidizer supply line 24, which may conduct an oxidizer to the gap 18, so that the oxidizer flows around it during use of the heater and is thereby cooled. 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, via which the exhaust gases are guided to the outside. Furthermore, a second flow path 146 is provided within the heat exchanger 200, in which cooling fluid of the motor vehicle is guided, e.g. air. The first 142 and the second 146 flow paths are arranged in such a way that heat is effectively transferred from the exhaust gases to the cooling fluid during use.

[0064] The circumferential wall component 14 shown in FIG. 1 is shown in greater detail in FIGS. 2 to 5. FIGS. 2 and 3 show the circumferential wall component 14 in a side view or a perspective view, respectively, while FIGS. 4 and 5 show views along the central axis C in the direction of the flange-side end or the flame tube-side end, respectively. The circumferential wall component 14 essentially comprises four sections, namely a flange 40, with which the circumferential wall component 14 can be connected to the base section 26 of the combustion chamber assembly 100, the circumferential wall 44, which is essentially provided in a form of a cylinder jacket, a conically tapering section 46 and a flame tube section 48.

[0065] The thin-walled circumferential wall component 14 is formed in one piece and preferably from a stainless steel alloy with a wall thickness d of 1 mm (see FIG. 7). An internal diameter of the circumferential wall 44 defining the combustion chamber 8 in its interior may be 45 mm, for example in the case of an air heater with an output of 1-5 KW. In the case of an air path with an output of 5-15 KW, the internal diameter may amount to 70 mm.

[0066] Whereas can be seen in FIG. 1the oxidizer supply chamber 20 extends around the circumferential wall 44 (annularly) as an antechamber, the structures 22 for feeding the oxidizer into the combustion chamber 8 and a plurality of smaller, radially directed inlet openings 42 are formed in the circumferential wall 44.

[0067] The structures 22 are arranged circumferentially in the circumferential direction P at equal distances from one another and at the same distance in the axial direction X from the flange 40 or the base section 26. FIGS. 4 and 5 show that four of the structures 22 are formed. The structures 22 comprise a cutout recess 52 and a worked section 54. The cutout recess 52 is in each case arranged behind the worked section 54 in the circumferential direction P, and directly adjoins the latter. The cutout recess 52 and the worked section 54 are contiguous. The cutout recess 52 forms a larger inlet opening as compared to the radially directed inlet openings 42. The oxidizer supply chamber 20 is in fluid communication with the combustion chamber 8 via the inlet openings 42 and the respective cutout recesses 52 as inlet openings of the structures 22.

[0068] FIGS. 2-5 also show in particular the cylindrical coordinate system used here for the description including the axial direction X, the radial direction R and the circumferential direction P. 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 defined locally in the circumferential wall, see FIG. 5.

[0069] FIGS. 6 and 7 show the structures 22 for introducing an oxidizer into the combustion chamber 8 in greater detail in plan view (FIG. 6) from the outside and in cross-sectional view (FIG. 7).

[0070] As described, the structure 22 comprises a worked section 54 and a cutout recess 52. In FIG. 6, the circumferential direction P is oriented parallel to line AA towards the left. The cutout recess 52 directly adjoins the worked section 54 in the circumferential direction P. The cutout recess 52 has an elongated shape in axial direction X (direction from bottom to top in FIG. 6) with two edge sections 60, 62 lying opposite each other in circumferential direction P. The first edge section 60 is formed in the flat, non-worked circumferential wall 44 and faces the worked section 54, while the second edge section 62 faces in the circumferential direction P. In the embodiment, the edge sections 60, 62 are formed parallel to each other. The cutout recess 52 is formed by removing material from the circumferential wall 44, for example in a punching process together with the formation of the inlet openings 42, or by laser cutting, etc.

[0071] The worked section 54like the cutout recess 52is mirror-symmetrical to an axis directed in the tangential direction T (corresponds to line AA in FIG. 6). The worked section 54 is deformed 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 matrix and stamp used for this process produce a convex shape for the worked section 54, which is curved radially towards the central axis C and thus has the shape of a flap, because the worked section 54 breaks off in the circumferential direction P at the second edge section 62 towards the cutout recess 52. As can be seen in FIG. 7, although the first edge section 60 lies opposite the second edge section 62 in the circumferential direction P, the second edge section 62 is positioned closer to the central axis C than the first edge section 60 due to the drawing depth z in the radial direction R.

[0072] In particular, an outwardly facing surface 443 adjacent to the second edge portion 62 and the inwardly facing surface 441 of the circumferential wall 44 adjacent to the first edge portion 60 provide a difference s with respect to their respective distances from the central axis C, which is 0.5 mm in the embodiment. In the embodiment the drawing depth z is 1.5 mm and the wall thickness d is 1 mm.

[0073] This selection of the quantities produces an inclined opening surface plane O for the inlet opening formed by the cutout recess 52, as shown in FIG. 9, which is analogous to FIG. 7. The surface normal N, which ideally corresponds to the flow direction of the oxidizer flowing through the inlet openings, consequently has a tangential component N.sub.T and a radial component N.sub.R. The tangential component N.sub.T thus generates a swirl in the combustion chamber 8, while the radial component N.sub.R prevents the Coanda effect and distributes the flow intensity homogeneously in the radial profile, thus improving mixing.

[0074] In FIG. 8, the length and width ratios for the cutout recess 52 and the worked section 54 are shown in a plan view of the structure 22 analogous to FIG. 6. A length is considered here in the circumferential direction P, a width in the axial direction X. In this view, the cutout recess 52 is almost twice as wide as it is long. The width w1 is 5.4 mm and the length 11 is 2 mm.

[0075] The width w2 of the worked section 54 is also 5.4 mm or slightly more in the specific embodiment, which does not limit the generality of the inventive concept, since the worked section 54 tapers laterally in axial direction X, as can be seen in FIG. 8. The length 12 of the worked section 54 along the axis (line AA in FIG. 6) in the circumferential direction P is also 5.4 mm up to the second edge section 62. On both sides in axial direction X, however, the worked section 54 also embraces the cutout recess 52, as revealed in FIGS. 6 and 8. The worked section 54 is thus longer than the cutout recess 52, while the widths w1, w2 are approximately comparable.

[0076] The information relates to an air heater with 1-5 KW, where the inner diameter of the circumferential wall is 45 mm. For air heaters with 5-15 KW, with an internal diameter of 70 mm, the dimensions are approximately twice as large.

[0077] The dimensions specified above may also be selected differently in modified embodiments, either individually or as a whole.

[0078] A further modified embodiment is shown in FIGS. 10 and 11. The worked section 54 is supplemented here by an extended worked section 56, with which the cutout recess 52 is embraced by the deformation of the circumferential wall 44 radially inwards towards the central axis C. As can be seen in FIG. 11, the first edge section 60 is also deformed in the radial direction R towards the central axis C. Overall, this measure shifts the cutout recess 52 or the inlet opening of the structure 22 provided by the cutout recess towards the central axis, so that it is raised relative to the surrounding and inwardly facing surface 441 of the circumferential wall 44. This also prevents the Coanda effect from occurring in this case.

[0079] The features of the invention disclosed in the above description, in the drawings and in the claims may be essential for the realization of the invention either individually or in any combination.

LIST OF REFERENCE SYMBOLS

[0080] 1 heating device [0081] 8 combustion chamber [0082] 10 evaporator receptacle [0083] 12 evaporator element [0084] 14 circumferential wall component [0085] 16 guide element for oxidizer [0086] 18 gap [0087] 20 oxidizer supply chamber [0088] 22 structures for introducing an oxidizer into the combustion chamber [0089] 24 oxidizer supply line [0090] 26 base section [0091] 30 side wall of the base section [0092] 32 ignition element [0093] 36 fuel supply tube [0094] 40 flange [0095] 42 radially directed smaller inlet openings [0096] 44 circumferential wall [0097] 46 conically tapering section [0098] 48 flame tube section [0099] 52 cutout recess [0100] 54 worked section (deformed section) [0101] 56 extension of the worked section [0102] 60 first edge section [0103] 62 second edge section [0104] 100 combustion chamber assembly [0105] 142 first flow path [0106] 144 exhaust gas outlet [0107] 146 second flow path [0108] 200 heat exchanger [0109] 441 radially inward-facing surface of the circumferential wall [0110] 442 radially outward-facing surface of the circumferential wall [0111] C central axis, cylinder axis, longitudinal axis of the circumferential wall [0112] X axial direction [0113] R radial direction [0114] P circumferential direction [0115] T tangential direction (within structure 22) [0116] d Wall thickness [0117] S difference with respect to respective distances from the central axis C [0118] Z Drawing depth