Combustion chamber assembly for a vaporizing burner, especially in a vehicle heater

Abstract

Combustion chamber assembly comprising a combustion chamber housing (14; 14a) with a bottom wall region (20; 20a) and a circumferential wall region (18; 18a), wherein at least one ignition element receiving projection (26; 26a) open to a combustion chamber (16; 16a) formed in the combustion chamber housing (14; 14a) is provided on the circumferential wall region (18; 18a), and a combustion air inlet arrangement (32; 32a) for the entry of combustion air supplied by a combustion air blower (42; 42a) into the combustion chamber (16; 16a) is provided on the bottom wall region (20; 20a), wherein the combustion air inlet arrangement (32; 32a) has a combustion air inlet projection (34; 34a) extending from the bottom wall region (20; 20a) in the direction of a longitudinal axis (A). comprising at least one combustion air inlet opening (64a), wherein the at least one combustion air inlet opening (64a) is connected to the at least one ignition element receiving projection (26;26a) not overlapping in the axial direction, characterized in that a second ratio of a minimum distance (M) of the at least one combustion air inlet opening from the bottom wall region (20; 20a) to the center distance (m) of an opening (68a) through which the at least one ignition element receiving projection (26; 26a) to the combustion chamber (16; 16a) is open, from the bottom wall region (20; 20a) lies in a range of 2.5 to 3.5.

Description

[0001] The present invention relates to a combustion chamber assembly for an evaporator burner, in particular in a vehicle heater, comprising a combustion chamber housing with a bottom wall region and a peripheral wall region, wherein at least one ignition element receiving attachment open to a combustion chamber formed in the combustion chamber housing is provided on the peripheral wall region and a combustion air inlet arrangement for the entry of combustion air conveyed by a combustion air blower into the combustion chamber is provided on the bottom wall region.

[0002] In such a combustion chamber assembly, the flow guidance for the combustion air can be such that it is conveyed into a combustion air guide chamber, also generally referred to as a plenum chamber, surrounding the combustion chamber housing in at least one region thereof. The majority of the combustion air enters the combustion chamber via the combustion air inlet arrangement, where it is mixed with vaporized fuel to form a combustible mixture. A portion of the combustion air flows toward the at least one ignition element receiving attachment and enters it in order to generate a mixture of combustion air and fuel vaporized in the region of this ignition element receiving attachment, even during an ignition phase.

[0003] Particularly with the use of alternative fuels, such as biodiesel, the problem arises with such combustion chamber assemblies that deposits form in the area of ​​an ignition element receiving attachment, which can, for example, lead to openings through which combustion air flows into the ignition element receiving attachment being closed or their flow cross-section being reduced.

[0004] A combustion chamber assembly according to the preamble of claim 1 is known from DE 197 17 544 A1.

[0005] It is the object of the present invention to provide a combustion chamber assembly for an evaporator burner, in particular in a vehicle heater, in which the risk of deposits forming, especially in the area of ​​an ignition element receiving attachment, can be reduced.

[0006] According to a first aspect of the present invention, this object is achieved by a combustion chamber assembly for an evaporator burner, in particular in a vehicle heater, comprising a combustion chamber housing with a bottom wall region and a peripheral wall region, wherein at least one ignition element receiving projection open to a combustion chamber formed in the combustion chamber housing is provided on the peripheral wall region and a combustion air inlet arrangement for the entry of combustion air conveyed by a combustion air into the combustion chamber is provided on the bottom wall region.

[0007] The combustion air inlet arrangement comprises a combustion air inlet projection extending from the bottom wall region in the direction of a longitudinal axis and having at least one combustion air inlet opening. The at least one combustion air inlet opening does not overlap with the at least one ignition element receiving projection in the axial direction.

[0008] The combustion is maintained at a distance from the opening of the at least one ignition element receiving attachment, since a second ratio of a minimum distance of the at least one combustion air inlet opening to the bottom wall region to the center distance of an opening, via which the at least one ignition element receiving attachment is open to the combustion chamber, to the bottom wall region is in a range of 2.5 to 3.5, preferably about 3.

[0009] This aspect of the invention shifts the combustion occurring in the combustion chamber to a region that essentially does not overlap, or only slightly overlaps, the region in which the ignition element receiving projection is open to the combustion chamber or is provided on the peripheral wall region of the combustion chamber housing. This leads to thermal relief of the at least one ignition element receiving projection and thus a reduction in the fuel deposits that form there.

[0010] It can further be provided that combustion air leaving the combustion air blower flows around the at least one ignition element receiving attachment on its flow path to the combustion air inlet arrangement.

[0011] This ensures that the combustion air, which is drawn in from the outside and is therefore comparatively cold, can flow around the at least one ignition element receiving attachment before entering the combustion chamber housing, thus dissipating heat from it. It has been shown that reducing the temperature in the area of ​​the at least one ignition element receiving attachment significantly reduces the formation of deposits in this area, especially when alternative fuels, such as biodiesel, are used.

[0012] The structure can, for example, be such that the combustion chamber housing is at least partially surrounded by a combustion air guide chamber, that the at least one ignition element receiving attachment extends in the combustion air guide chamber and that a combustion air outlet of the combustion air blower is open to the combustion air guide chamber, wherein it can further preferably be provided that the combustion air emerging from the combustion air outlet flows in the direction of the at least one ignition element receiving attachment.

[0013] In a variant that is structurally very simple to implement and very advantageous in terms of the achievable cooling effect of the combustion air, it is proposed that the combustion air outlet be oriented such that the combustion air exiting it flows essentially directly toward the at least one ignition element receiving attachment. Thus, the combustion air flows toward the at least one ignition element receiving attachment essentially without thermal interaction with other components that are generally already heated during combustion operation, thus efficiently cooling it.

[0014] In an alternative embodiment, a combustion air guide arrangement can be provided in the combustion air guide chamber for directing the combustion air exiting from the combustion air outlet toward the combustion air inlet arrangement such that the combustion air flows around the at least one ignition element receiving attachment. The use of a combustion air guide arrangement can ensure that the combustion air flow is focused toward the at least one ignition element receiving attachment, thereby achieving increased interaction between the combustion air flow and the at least one ignition element receiving attachment.

[0015] In this case, it can be provided, for example, that the combustion air guide arrangement comprises a combustion air guide circumferential wall which at least partially surrounds the circumferential wall region of the combustion chamber housing in its region surrounded by the combustion air guide chamber in the circumferential direction.

[0016] Furthermore, the defined flow guidance for the combustion air flow can be supported in that the combustion air guide arrangement comprises a combustion air guide floor wall which adjoins the combustion air guide peripheral wall and essentially completely covers the floor wall area of ​​the combustion chamber housing.

[0017] The combustion air guide chamber surrounding the combustion chamber housing is generally axially adjoined by the heat exchanger region of a heater. This means that in this adjacent region, the combustion air guide chamber will be delimited by components or assemblies which have a comparatively high temperature during combustion operation. In order to limit the thermal interaction of the combustion air introduced into the combustion air guide chamber, particularly before it flows around the at least one ignition element receiving attachment with such assemblies, it is proposed that the combustion air guide arrangement comprise a combustion air guide insulating wall adjoining the combustion air guide circumferential wall in the circumferential extension region of the combustion air guide circumferential wall, axially delimiting the flow space for the combustion air in the combustion air guide chamber in the direction of a longitudinal axis of the combustion chamber housing.It can preferably be provided that the combustion air guide insulating wall extends radially outwards from the combustion air guide peripheral wall essentially to a chamber peripheral wall surrounding the combustion air guide chamber.

[0018] In order to be able to conduct sufficient combustion air in the combustion chamber in the arrangement according to the invention of one or more combustion air inlet openings in the combustion air inlet attachment with the aim of keeping the combustion in a region of the combustion chamber which is as far away as possible from the region in which the at least one ignition element receiving attachment is open to the combustion chamber, but at the same time to be able to conduct sufficient combustion air in the combustion chamber, it is proposed that a first ratio of a length of the combustion air inlet attachment to an internal dimension of the combustion air inlet attachment is in the range from 1.4 to 2.6, preferably 1.54 to 2.45.

[0019] If the at least one combustion air inlet opening is provided in the peripheral wall of the combustion air inlet attachment, it has proven advantageous if the first ratio is in the range from 2.4 to 2.6, preferably approximately 2.45.

[0020] If the at least one combustion air inlet opening is provided on the front side of the combustion air inlet attachment, the first ratio can be in the range of 1.5 to 1.6, preferably approximately 1.54.

[0021] The present invention is described in detail below with reference to the accompanying figures, each of which shows a schematic representation: Fig. 1 a longitudinal view of a combustion chamber assembly; Fig. 2 one of the Fig. 1 corresponding view of an alternative design; Fig. 3 the combustion chamber assembly of the Fig. 2 in axial plan view; Fig. 4 one of the Fig. 2 shows a modified design; Fig. 5 an axial plan view of the combustion chamber assembly of the Fig. 4; Fig. 6 is a longitudinal view of a combustion chamber assembly illustrating the design principles of the present invention.

[0022] In the Fig. 1 shows a vehicle heater, generally designated 10, with its components essential for explaining the principles of the present invention. The vehicle heater 10 comprises a combustion chamber assembly 12 with a combustion chamber housing 14, in which a combustion chamber, generally designated 16, is formed. The combustion chamber housing 14, in turn, comprises a peripheral wall region 18 and, adjoining this, a bottom wall region 20, so that a generally pot-like structure of the combustion chamber housing 14 results. In the direction of a longitudinal axis A of the combustion chamber assembly 12, the combustion chamber housing 14 is open or merges into a flame tube 22, which is surrounded by a heat exchanger assembly 24, shown here only with an inner wall, for transferring the heat generated during combustion to a medium to be heated, for example air or water.

[0023] At least one ignition element receiving projection 26 is provided, extending approximately tangentially, on the peripheral wall region 18 of the combustion chamber housing 14. An ignition element, for example a glow plug, is provided within this projection. The ignition element receiving projection 26 and the peripheral wall region 18 are lined on their inside with a porous evaporator medium, so that liquid fuel is distributed therein by capillary action and evaporates into the interior of the ignition element receiving projection 26 or the combustion chamber 16. The liquid fuel is supplied via a fuel supply line 28, which opens into the ignition element receiving projection 26. If several such ignition element receiving projections 26 are provided distributed over the circumference, they can of course each be fed with its own fuel supply line 28.

[0024] A combustion air guide device 30 is provided on the bottom wall region 20 of the combustion chamber housing 14, which, for example, comprises a plurality of guide walls extending substantially radially and curvedly with respect to the longitudinal axis A, which convey combustion air from the radial outside into a central region of the bottom wall region 20, where the combustion air can then flow into the combustion chamber 18 via a combustion air inlet arrangement generally designated 32. In the example shown, this combustion air inlet arrangement 32 comprises a combustion air inlet extension 34 extending into the combustion chamber 16 from the bottom wall region 20 and having at least one combustion air inlet opening.

[0025] The combustion chamber housing 14 is surrounded at least in a partial area of ​​its axial extent by a combustion air guide chamber 36. This is delimited on the outside by a chamber housing 39, which is positioned at a distance from the peripheral wall area 18 and the bottom wall area 20 or from the combustion air guide device 30. In the direction of the longitudinal axis A, the combustion air guide chamber is delimited by a flange area 38, which is formed, for example, integrally with the combustion chamber housing 14 and which essentially also separates the combustion air guide chamber 36 from the heat exchanger area 24 or an exhaust gas flow space 40. Fig. 1 further that the at least one ignition element receiving projection 26 is located in a region of the combustion chamber housing 14 which is surrounded by the combustion air guide chamber 36, wherein the ignition element receiving projection 26 also extends into the combustion air guide chamber 36.

[0026] At 42, in the Fig. 1 generally indicates a combustion air blower, which can be designed in the manner of a side-channel blower. A ring-shaped conveyor wheel 44, driven by a drive motor 46, rotates above a corresponding ring-shaped conveyor channel 48 with an interrupter area (not shown here). The combustion air conveyed in the conveyor channel 48 by the rotation of the conveyor 44 leaves the area of ​​the combustion air blower 42 via a combustion air outlet 50 toward the combustion air guide chamber 36.

[0027] One can see in the Fig. 1, that the combustion air outlet 50 of the combustion air blower 42 is positioned or oriented such that the combustion air exiting it flows essentially directly towards the ignition element receiving attachment 26 without prior deflection. This means that the ignition element receiving attachment 26 is substantially surrounded by all of the combustion air entering the combustion air guiding chamber 36 before said air flows around the combustion chamber housing 14 from the radial outside into the combustion air guiding device 30 and through this, generating a flow swirl radially inwards and then via the combustion air inlet attachment 34 into the combustion chamber 16.

[0028] By flowing comparatively cold combustion air around the ignition element receiving attachment 26, the temperature in this ignition element receiving attachment 26 can be maintained at a level that ensures that the temperature of the fuel supplied via the fuel supply line 28 does not rise above 80°C, even during combustion. It has been shown that this is a temperature level, in particular, which, if exceeded, promotes the formation of polymers and thus the generation of deposits. If combustion air flows around the ignition element receiving attachment 26 and thus in particular also the area of ​​the fuel supply line 28 that opens into it, in the example of the Fig. 1 even before it comes into contact with warmer components, efficient cooling of the ignition element receiving attachment 26 can be achieved.

[0029] An alternative design is in the Fig. 2 and Fig. 3. In particular, the structure of the combustion chamber housing 14 can correspond to that described above.

[0030] In the Fig. 2 and Fig. 3, a combustion air guide arrangement, generally designated 52, is provided in the combustion air guide chamber 36. This comprises a combustion air guide circumferential wall 54, which, starting from the flange region 38, extends substantially parallel to the circumferential wall region 18 of the combustion chamber housing 14. The combustion air guide circumferential wall 54 can, for example, be manufactured integrally with the flange region 38 in a casting process. Alternatively, this combustion air guide circumferential wall 54 can also be soldered to the flange region 38 as a separate component. The combustion air guide circumferential wall 54 is arranged such that, starting from the combustion air outlet 50 of the combustion air blower 42, it initially guides the combustion air in the circumferential direction and at a distance from the circumferential wall region 18, as flow arrows in Fig. 3, as indicated, in the circumferential direction around the combustion chamber housing 14 without any significant thermal contact of the combustion air with the circumferential wall region 18 being able to occur. Where the ignition element receiving attachment 26 extends from the circumferential wall region 18, the combustion air guiding circumferential wall 54 adjoins, for example, the circumferential wall region 18, so that the combustion air then flowing further in the circumferential direction first flows around the ignition element receiving attachment 26 before flowing further in the circumferential direction along the circumferential wall region 18 and can then enter the combustion chamber housing 14 via the combustion air guiding device 30.

[0031] To support this flow guidance, the combustion air guide arrangement further comprises a combustion air guide base wall 56, which essentially completely covers the combustion chamber housing 14 and leaves free in the axial direction only that area in which the air flowing in from the combustion air outlet 50 flows first in the axial direction and then through the combustion air guide circumferential wall 54 in the circumferential direction toward the ignition element receiving projection 26. The combustion air guide base wall 56 can be secured, for example, to the combustion air guide device 30 by a plurality of rivet pins and can also close it off in the axial direction, for example as a component thereof.Thus, for the combustion air flowing in the direction of the combustion chamber 16, a spiral-like flow space is created which is axially delimited by the flange region 38 on the one hand and the combustion air guide base wall 56 on the other hand, into which at least one ignition element receiving projection 26 extends in an area which, for example, is not yet covered by the combustion air guide base wall 56 and is thus axially delimited.

[0032] An advantage of the Fig. 2 and Fig. 3 is that in combustion chamber assemblies with several ignition organ receiving projections distributed over the circumference, it can be ensured that all of these ignition organ receiving projections are captured by the spiral-shaped combustion air flow and thus cooled.

[0033] A modification of this design of a combustion chamber assembly is shown in the Fig. 4 and Fig. 5. Here, too, the combustion air guide arrangement 52 can be seen with its combustion air guide circumferential wall 54 and its combustion air guide base wall 56. Furthermore, in this embodiment, the combustion air guide arrangement 52 has a combustion air insulation wall 58. This wall adjoins the combustion air guide circumferential wall 54 at its axial end region remote from the combustion air guide base wall 56 and extends radially outward from the combustion air guide circumferential wall 54. The combustion air insulation edge 58 thus delimits the air flow space for the combustion air in the combustion air chamber 36 in the circumferential region in which the combustion air guide circumferential wall 54 also extends, even before the flange region 38.As a result, the combustion air, which is initially guided in the circumferential direction by the combustion air guide circumferential wall 54 at a distance from the circumferential wall region 18 of the combustion chamber housing 14, does not come into contact with the flange region 38, which is heated to a very high degree by the combustion exhaust gases or the combustion chamber housing 14 itself. The temperature level of the combustion air flowing onto the ignition element receiving attachment 26 can thus be reduced even further.

[0034] In order to utilize the effect introduced by the combustion air guide insulating wall 58 very efficiently, it is preferably positioned so that it has no contact with the flange area 38 or is separated from it by thermal insulating material, if necessary.

[0035] In Fig. Figure 6 shows a combustion chamber assembly for a vehicle heater, illustrating the design principles of the present invention. Components that correspond to previously described components in terms of structure or function are designated by the same reference numerals with the addition of an "a" suffix.

[0036] One can see in the Fig. 6 shows the combustion chamber housing 14a in a generally open manner, with the combustion air inlet extension 34a of the combustion air inlet arrangement 32a extending therein from the bottom wall region 20a. Also visible is the ignition element receiving extension 26a, which is open to the combustion chamber 16a and into which the fuel supply line (not shown here) can again open. The combustion chamber 16a is essentially delimited by a flame shield 60a where the combustion chamber housing 14a merges into the flame tube 22a.

[0037] The combustion air inlet extension 34a is substantially cylindrical in shape with a peripheral wall 62a. Elongated, slot-like combustion air inlet openings 64a are provided in this wall at an axial end region remote from the bottom wall region 20a, through which the air, guided with swirl into the combustion air inlet extension 34a by means of the combustion air guide device 30a, enters the combustion chamber 16a.

[0038] The length of the combustion air inlet extension 34a is matched to the axial positioning or extension of the inlet openings 64a such that an axial distance D exists between them and the ignition element receiving extension 26a, i.e., there is no axial overlap. This means that the combustion in the combustion chamber 16a is shifted to a region closer to the flame aperture 60a. Essentially no combustion will take place in the axial region of the combustion chamber 16a in which the ignition element receiving extension 26a is also located, so that heating of the ignition element receiving extension 26a caused by combustion is reduced to a lower level during combustion operation.As a result, even taking into account the fact that the combustion air guide chamber 36a, into which the ignition element receiving attachment 26a extends, is flowed through by comparatively cold combustion air, the temperature level in the region of the ignition element receiving attachment 26a is kept comparatively low, thus significantly reducing the risk of deposits forming. In order to provide sufficient volume for combustion in the combustion chamber 16a, the flame aperture 60a can be displaced axially away from the bottom wall region 20a compared to a variant with a shorter combustion air inlet attachment 34a.

[0039] The combustion air inlet approach 34a can, as shown in the Fig. 6, have a plurality of slot-like inlet openings 64a formed in the peripheral wall 62a at its free end region. Alternatively, however, it is also possible to design the peripheral wall 62a to be substantially closed and to keep an end face 66a of the combustion air inlet extension 34a open, for example, across the entire cross-section of the combustion air inlet extension 34a, so that it can also fulfill the functionality of a swirl tube.

[0040] At the Fig. 6, the combustion air inlet projection 34a is thus extended or designed with such a length that the combustion air inlet region closest to the bottom wall region 20a does not overlap axially with an opening 68a, through which the ignition element receiving projection 26a is open to the combustion chamber 16a, or is also at an axial distance D from it. In order to nevertheless be able to introduce sufficient combustion air into the combustion chamber 16a, it has proven advantageous to set a first ratio L / d of the projection length L of the combustion air inlet projection 34a above the bottom wall region 20a to the inner dimension d, i.e. essentially the inner diameter in a cylindrical design, when the combustion air inlet openings 64a are provided in the peripheral wall 62a, such that this ratio is in the range from 2.4 to 2.6, preferably approximately 2.45.If the combustion air inlet opening is provided on the end face 66a, i.e. the combustion air inlet extension 34a is not open in its peripheral wall 62a, this ratio can preferably be in the range of 1.5 to 1.6, preferably approximately 1.54.

[0041] According to the invention, a second ratio M / m lies between the minimum distance of a combustion air inlet opening in which Fig. 6 of the combustion air inlet openings 64a, to the bottom wall region 20 and the center distance m of the opening 66a to the bottom wall region 20a in the range of 2.5 to 3.5, preferably approximately 3. When providing the combustion air inlet opening on the front side 66a, the size M essentially also corresponds to the projection length L of the combustion air inlet extension 34a above the bottom wall region 20a.

[0042] Of course, the Fig. 6 shown constructive measures with the design variants of the Fig. 1 to 5 are combined so that, on the one hand, by the combustion air guidance and, on the other hand, by limiting the combustion to an area of ​​the combustion chamber remote from the ignition element receiving attachment, the temperature level of the ignition element receiving attachment can be reduced to such an extent that the formation of fuel deposits of the liquid fuel introduced into it can be prevented as far as possible.

Claims

[1] Combustion chamber assembly, comprising a combustion chamber housing (14; 14a) with a bottom wall region (20; 20a) and a peripheral wall region (18; 18a), wherein at least one ignition element receiving projection (26; 26a) open to a combustion chamber (16; 16a) formed in the combustion chamber housing (14; 14a) is provided on the peripheral wall region (18; 18a), and a combustion air inlet arrangement (32; 32a) for the entry of combustion air conveyed by a combustion air blower (42; 42a) into the combustion chamber (16; 16a) is provided on the bottom wall region (20; 20a), wherein the combustion air inlet arrangement (32; 32a) has a combustion air inlet projection extending from the bottom wall region (20; 20a) in the direction of a longitudinal axis (A) (34; 34a) with at least one combustion air inlet opening (64a), wherein the at least one combustion air inlet opening (64a) does not overlap with the at least one ignition element receiving projection (26; 26a) in the axial direction,characterized by that a second ratio of a minimum distance (M) of the at least one combustion air inlet opening from the bottom wall region (20; 20a) to the center distance (m) of an opening (68a), via which the at least one ignition element receiving projection (26; 26a) is open to the combustion chamber (16; 16a), from the bottom wall region (20; 20a) lies in a range of 2.5 to 3.

5. [2] Combustion chamber assembly according to claim 1, characterized by that at least one combustion air inlet opening (64a) is provided in a peripheral wall (62a) of the combustion air inlet attachment (34a). [3] Combustion chamber assembly according to claim 1 or 2, characterized by that at least one combustion air inlet opening is provided on one end face of the combustion air inlet attachment (34a). [4] Combustion chamber assembly according to one of claims 1 to 3, characterized bythat a first ratio of a length (L) of the combustion air inlet extension (34a) to an internal dimension (d) of the combustion air inlet extension (34a) is in the range from 1.4 to 2.6, preferably 1.54 to 2.

45. [5] Combustion chamber assembly according to claim 2 and claim 4, characterized by that when at least one combustion air inlet opening (64a) is provided in the peripheral wall (62a) of the combustion air inlet extension (34a), the first ratio is in a range of 2.4 to 2.6, preferably about 2.

45. [6] Combustion chamber assembly according to claim 3 and claim 4, characterized by that when at least one combustion air inlet opening is provided on the end face (66a) of the combustion air inlet extension (34a), the first ratio is in the range from 1.5 to 1.6, preferably approximately 1.

54. [7] Combustion chamber assembly according to one of claims 1 to 6, characterized bythat the second ratio is approximately 3. [8] Combustion chamber assembly according to one of claims 1 to 7, characterized by that combustion air leaving the combustion air blower (42) flows around the at least one ignition element receiving attachment (26) on its flow path to the combustion air inlet arrangement (32). [9] Combustion chamber assembly according to claim 8, characterized by that the combustion chamber housing (14) is at least partially surrounded by a combustion air guide chamber (36), that the at least one ignition element receiving projection (26) extends in the combustion air guide chamber (36) and that a combustion air outlet (50) of the combustion air blower (42) is open to the combustion air guide chamber (36). [10] Combustion chamber assembly according to claim 9, characterized by that the combustion air emerging from the combustion air outlet (50) flows in the direction of the at least one ignition element receiving attachment (26). [11] Combustion chamber assembly according to claim 10, characterized by that the combustion air outlet (50) is oriented such that combustion air emerging from it flows substantially directly towards the at least one ignition element receiving attachment (26). [12] Combustion chamber assembly according to claim 9 or 10, characterized by that a combustion air guide arrangement (52) is provided in the combustion air guide chamber (36) for guiding the combustion air emerging from the combustion air outlet (50) in the direction of the combustion air inlet arrangement (32) in such a way that the combustion air flows around the at least one ignition element receiving attachment (26). [13] Combustion chamber assembly according to claim 12, characterized bythat the combustion air guide arrangement (52) comprises a combustion air guide peripheral wall (54) which at least partially surrounds the peripheral wall region (18) of the combustion chamber housing (14) in the region surrounded by the combustion air guide chamber (36). [14] Combustion chamber assembly according to claim 13, characterized by that the combustion air guide arrangement (52) comprises a combustion air guide bottom wall (56) which adjoins the combustion air guide peripheral wall (54) and essentially completely covers the bottom wall region (20) of the combustion chamber housing (14). [15] Combustion chamber assembly according to claim 13 or 14, characterized bythat the combustion air guide arrangement (52) comprises, adjoining the combustion air guide circumferential wall (54), a combustion air guide insulating wall (58) which axially delimits the flow space for the combustion air in the combustion air guide chamber (36) in the direction of a longitudinal axis (A) of the combustion chamber housing (14) in the circumferential extension region of the combustion air guide circumferential wall (54). [16] Combustion chamber assembly according to claim 15, characterized by that the combustion air guide insulating wall (58) extends radially outwards from the combustion air guide peripheral wall (54) essentially to a chamber peripheral wall (39) surrounding the combustion air guide chamber (36).

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