EP2980505B1 - Heat exchanger assembly, in particular for a vehicle heating device - Google Patents

Description

The present invention relates to a heat exchanger arrangement, in particular for a vehicle heater, comprising a pot-like inner heat exchanger housing having a first bottom wall in a first axial end portion of the heat exchanger assembly and a first circumferential wall adjacent to the first bottom wall, surrounding a longitudinal axis, a cup-shaped outer heat exchanger housing having a second bottom wall in the first axial end region of the heat exchanger arrangement and a second peripheral wall adjoining the second bottom wall, the inner heat exchanger housing and the outer heat exchanger housing being connected to one another in a second axial end region of the heat exchanger arrangement, and one formed between the inner heat exchanger housing and the outer heat exchanger housing Fluid flow space, according to the preamble of claim 1.

From the DE 197 49 809 A1 a heat exchanger assembly for a fuel-powered vehicle heater according to the preamble of claim 1 is known in which in one of the bottom walls of the two cup-like and one another heat exchanger housing remote axial end portion of the heat exchanger assembly, the interior of the two heat exchanger housing is double-walled. In this area, the inner heat exchanger housing bounded with an annular wall around a housing longitudinal axis circumferential end wall bounds the fluid flow space formed between the two heat exchanger housings in the axial direction and is connected with its likewise annular peripheral outer peripheral wall to the peripheral wall of the outer heat exchanger housing. In the axial end region of the heat exchanger arrangement, which is remote from the bottom walls, there is an exhaust gas outlet opening, provided in an exhaust gas outlet connection, intended. This nozzle breaks through the fluid flow space with the exhaust outlet opening formed therein and is open to an exhaust gas flow space surrounded by the inner heat exchanger housing. The fluid inlet opening leading to the fluid flow space, and also the fluid outlet opening leading away from the fluid flow space, are formed in the outer heat exchanger housing in the outer heat exchanger housing in respective connecting pieces in the axial end region of the heat exchanger arrangement close to the bottom walls.

From the DE 34 16 878 A1 is also a heat exchanger assembly for a vehicle heater according to the preamble of claim 1, in which an outer peripheral wall and an inner peripheral wall and connecting webs are integrally formed as extruded profile part. At a first axial end region, the two peripheral walls are each connected to a cap-like bottom wall. At a second axial end region, the two peripheral walls and the webs provide a contact surface on which a burner unit to be connected to the heat exchanger arrangement rests in the assembled state. In which the two peripheral walls providing extrusion component through-holes are provided, in which fastening means for attaching the burner unit can be introduced. Furthermore, baseboards are formed on this component, which serve as a stand of a constructed with such a heat exchanger assembly heater.

It is the object of the present invention to provide a heat exchanger arrangement, in particular for a vehicle heater, in which heat losses are reduced.

According to the invention this object is achieved by a heat exchanger arrangement, in particular for a vehicle heater, according to claim 1. This comprises a pot-like inner heat exchanger housing with a first bottom wall in a first axial end region of the heat exchanger assembly and a first circumferential wall adjoining the first bottom wall and surrounding a longitudinal axis cup-shaped outer heat exchanger housing with a second bottom wall in the first axial end region of the heat exchanger assembly and a second peripheral wall adjoining the second bottom wall, surrounding the longitudinal axis second peripheral wall, wherein in a second axial end portion of the heat exchanger assembly, the inner heat exchanger housing and the outer heat exchanger housing are interconnected, and one between the inner heat exchanger housing and the outer Heat exchanger housing formed fluid flow space. It is further provided that at least one outwardly open recess is provided at least in the second axial end portion of the heat exchanger assembly in the building material of the inner heat exchanger housing and / or in the building material of the outer heat exchanger housing.

It is further provided that at least one in the construction material of the inner heat exchanger housing and / or in the building material of the outer heat exchanger housing to the outside open recess is provided at least in the second axial end region of the heat exchanger assembly.

By providing at least one recess in the building material of the inner heat exchanger housing and / or the building material of the outer heat exchanger housing a generally filled with air, but basically closed to the fluid flow space cavity is provided. Since the two heat exchanger housings, or at least the inner heat exchanger housings which are more strongly acted upon by the hot combustion gases, are generally constructed of metal material, for example of die-cast aluminum material, the introduction of recesses in this construction material ensures an interruption in the metal material. Since the building material of the heat exchanger assembly or the heat exchanger housing thereof generally has a significantly higher thermal conductivity, and thus a lower thermal resistance than, for example, the air present in such a recess, the Wärmeaustrag from the heat exchanger assembly by the thus generally provided greater thermal resistance in the region of the recesses reduced.

In order to avoid mutual interference with the fluid flow space, at least one recess is open to the outside at an end face remote from the bottom walls, essentially in the axial direction.

An easy-to-realize, yet stable structure can be obtained by providing a plurality of circumferentially successive recesses in the circumferential direction, or / and that at least one, preferably each recess is curved about the longitudinal axis and / or elongated in the circumferential direction.

In order to allow a flow through the fluid flow space with a fluid to be heated or to ensure the discharge of combustion exhaust gases, for example generated in a burner region of a vehicle heater, a fluid inlet opening to the fluid flow space and / or a fluid outlet opening from the fluid flow space is provided in the second axial end region. Furthermore, in the second axial end region, an exhaust gas outlet opening may be provided from an exhaust gas flow space surrounded by the inner heat exchanger housing.

In order to provide sufficient installation space for such inlet or outlet openings, it is proposed that at least one recess provided in the peripheral region of the fluid inlet opening and / or at least one recess in the peripheral region of the fluid outlet opening and / or at least one recess provided in the peripheral region of the exhaust gas outlet opening has a smaller depth at least in regions than a recess provided in a peripheral area substantially unintersecting with the fluid inlet opening and / or the fluid outlet opening and / or the exhaust gas outlet opening and / or the exhaust gas outlet opening. The result of this construction is that, where there is no interference with a fluid inlet opening or exhaust outlet opening, recesses or a recess with a correspondingly greater depth can be provided, which leads to a further increase in the thermal resistance.

A compact embodiment of the heat exchanger arrangement is achieved in that, in the second axial end region, the inner heat exchanger housing has an end wall axially delimiting the fluid flow space. Furthermore, in the second axial end region, the inner heat exchanger housing may have a third circumferential wall which engages over the second peripheral wall on its outer side and is connected thereto.

The end wall is formed circumferentially ring-like. However, in order to be able to ensure the flow of fluid to the fluid inlet opening or to the fluid outlet opening, the fluid flow space in the axial direction extends beyond the end wall in the area of the fluid inlet opening or / and in the area of the fluid outlet opening. This means that in the region of these openings, the otherwise annularly circumferentially formed end wall may be interrupted or these openings may have surrounding bulges.

In order to avoid the accumulation of impurities in the region of the heat exchanger arrangement, it is further proposed that at least one recess is closed off by a closure element.

The introduced by the provision of at least one recess in the building material of a heat exchanger housing thermal insulation effect can be used in a particularly efficient manner, if in at least one recess, preferably each recess, insulating material with lower thermal conductivity than the building material of this recess having heat exchanger housing is included.

In this case, the insulating material preferably fills the at least one recess (60) substantially completely.

In an embodiment that is particularly easy to implement and provides very efficient thermal insulation, the insulating material may comprise air. It should be noted here that in a further embodiment variant, a combination of different thermally insulating insulating materials can be provided can. For example, in at least one recess porous or cell-like constructed, foam-like material may be included in the inner volume of air is received. For example, PU foam or foamed silicone material can be used

The building material of at least one recess having a heat exchanger housing preferably comprises metal material, preferably aluminum. Advantageously, metal material, for example aluminum, forms the main constituent component of the building material, in particular if this building material is provided as an alloy.

Fig. 1

eine perspektivische Ansicht einer Wärmetauscheranordnung;

Fig. 2

eine Längsschnittansicht der Wärmetauscheranordnung der Fig. 1, geschnitten längs einer Linie II-II in Fig. 3;

Fig. 3

eine Axialansicht der Wärmetauscheranordnung der Fig. 1;

Fig. 4

eine der Fig. 2 entsprechende Längsschnittansicht der Wärmetauscheranordnung in Verbindung mit einer Brennkammerbaugruppe eines Fahrzeugheizgeräts.

The present invention will be described below in detail with reference to the accompanying drawings. It shows:

Fig. 1

a perspective view of a heat exchanger assembly;

Fig. 2

a longitudinal sectional view of the heat exchanger assembly of Fig. 1 , cut along a line II-II in Fig. 3 ;

Fig. 3

an axial view of the heat exchanger assembly of Fig. 1 ;

Fig. 4

one of the Fig. 2 corresponding longitudinal sectional view of the heat exchanger assembly in conjunction with a combustion chamber assembly of a vehicle heater.

In the figures, a heat exchanger assembly employable, for example, in connection with a fuel-fired vehicle heater is generally indicated at 10. The heat exchanger assembly 10 comprises two heat exchanger housings 12, 14 inserted one inside the other. The inner heat exchanger housing 12 comprises a first bottom wall 18 in a first axial end region 16 of the heat exchanger assembly 10 and radially adjoining the latter and extending in the direction of a longitudinal axis L or surrounding the longitudinal axis L. a first circumferential wall 20. The outer heat exchanger housing 14 includes in It should be noted here that in the illustrated embodiment, the two heat exchanger housing 12, 14 with their bottom walls 18, 22 and their peripheral walls 20, 24 are each constructed as integrally formed components, these manufactured for example as aluminum Druckgrussteile. In principle, in one or both of the heat exchanger housings 12, 14, the peripheral walls or bottom walls could also be provided as separately constructed and interconnected components.

In a second axial end region 26 of the heat exchanger arrangement 10 remote from the bottom walls 18, 22, the inner heat exchanger housing 12 with an annular end section 28 forms a connection to the outer heat exchanger housing 14. In this annular end section 28, the inner heat exchanger housing 12 extends beyond its second circumferential wall 20 In addition, radially outward and has a third circumferential wall 30 extending toward the first axial end portion. This third peripheral wall 30 engages over the second circumferential wall 24 radially outward and is fixedly connected to it by intermediate storage of an O-ring-like sealing element 32, for example by pressing, welding, gluing or the like. In this way, between the inner heat exchanger housing 12 and the outer heat exchanger housing 14, a generally designated 34 fluid flow space formed in the axial direction at the second axial end portion 26 by a between the first peripheral wall 20 and the third peripheral wall 30 of the inner heat exchanger housing 12 itself extending end wall 36 is completed or limited. This end wall 36 is formed around the longitudinal axis L ring-like circumferential, is advantageously substantially in an axial region with respect to the longitudinal axis L, that is substantially orthogonal thereto, and is how the Fig. 2 this shows, formed in this area substantially plan, but could in principle also be provided with a conical or frusto-conical structure.

In the connecting region 28, which extends axially beyond the outer heat exchanger housing 14, the inner heat exchanger housing 12 has a fluid inlet opening 40 formed in a fluid inlet stub 38 and a fluid outlet opening 44 provided in a fluid outlet stub 42. The fluid inlet port 40 and the fluid outlet port 44 are open to the fluid flow space 34. As the Fig. 2 this shows, the nozzles 40, 42 are arranged substantially at the axial side facing away from the fluid flow space 34 with respect to the end wall 36. In order nevertheless to produce a fluid exchange connection, where the fluid inlet opening 40 or the fluid outlet opening 44 is provided, the otherwise annular peripheral end wall 36 is interrupted, so that in connection with the fluid flow space 34 and also in communication with the respective opening 40 and 44th standing bulge in the end portion 28 is formed.

In the second axial end region 26 of the heat exchanger arrangement 10, an exhaust gas outlet opening 48 is furthermore provided in an exhaust gas outlet connection 46. This is open to the inside of the first peripheral wall 20 and thus to a surrounding of the inner heat exchanger housing 12 exhaust gas flow chamber 50. As the Fig. 4 This shows that in a combustion chamber assembly 52 and a combustion chamber 54 of the same resulting combustion exhaust gases are passed through an intervening in the inner heat exchanger housing 12 positioned flame tube 56 in the direction of the first bottom wall 18. After hitting the first bottom wall 18, the combustion exhaust gases are deflected radially outward and then flow back in the exhaust gas flow space 50 from the first axial end portion 16 to the second axial end portion 26 and the exhaust outlet opening 48 provided there. At this time, the combustion exhaust gases flow along heat transfer fins 58 provided on an inner side of the inner heat exchanger case 12 for enlarging the heat transfer surface.

In the illustrated embodiment, in the second axial end region 26 of the heat exchanger arrangement 10, in the inner heat exchanger housing 12, in particular in the space adjoining the fluid flow space 34 End portion 28 thereof, a plurality of, for example, in a casting manufacturing process of the inner heat exchanger housing 12 and / or provided by machining recesses 60 provided in the building material of the inner heat exchanger housing 12. The recesses 60 are arranged successively in the circumferential direction about the longitudinal axis L and have, for example, mutually equal circumferential extents and / or radial extents. The recesses 60 are preferably, adapted to the annular shape of the heat exchanger housing, curved or / and elongated in the circumferential direction. Between the individual recesses 60 are these separating walls 62. The axial depth of the recesses 60 is dimensioned such that the Fig. 2 This clearly shows, between the end wall 36 and a respective bottom portion 64 of the recesses 60 a the recesses 60 from the fluid flow space 34 separating wall portion 66 is formed. Where a circumferential overlap of recesses 60 with the fluid inlet port 40, the fluid outlet opening 44 and the exhaust outlet opening 48 and the openings 38, 42, 46 providing these openings, the recesses 60, as in the area 68 in FIG Fig. 1 and Fig. 3 recognizable be formed with less recess depth. In the circumferential regions which do not overlap with these openings or connecting pieces, the recesses 60 preferably each have the same depths which maximize the available axial space in the end section 28. By providing the outward openings 60, which are open in the axial direction in the example shown, cavities are created in the building material of the heat exchanger arrangement, in particular of the inner heat exchanger housing 12, which is subjected to relatively high thermal stress by the hot combustion exhaust gases. Through these cavities or interruptions in the building material of the heat exchanger assembly or the inner heat exchanger housing 12, the heat flow to the outside is reduced to the environment, since in the region of the recesses 60, a higher thermal resistance is present, as in that area, in which building material of the inner heat exchanger housing 12th is present, for example in the region of the wall 66. Heat losses can thus be reduced, in particular in the second axial end region 26.

As the Fig. 4 As shown in FIG. 14, a support 72 connecting the combustion chamber assembly 52 and the heat exchanger assembly 10 to, for example, the flame tube 56 or combustion chamber wall 70 at the end face 74 at which the recesses 60 in the building material of the inner heat exchanger housing 12 are axially open, can Cover recesses 60 or at least part of it. Here, for example, a ring-shaped, flexible sealing element 75 may be stored. The fixed connection of the carrier 72 to the inner heat exchanger housing 12 can be provided, for example, by the carrier 72 in its radially outwardly extending and also the recesses 60 cross-section passing and introduced into the connecting portion 28 of the inner heat exchanger housing 12 bolts.

In order to efficiently use the insulating effect introduced by providing the recesses 60, some, preferably all recesses 60 are filled with thermally insulating material. Thermally insulating here means that the material with which the recess / s 60 is / are filled, has a lower thermal conductivity, as the construction material of these recesses 60 having heat exchanger housing. For example, these recesses 60 may be substantially completely filled with air which has orders of magnitude smaller thermal conductivity than the aluminum material used for constructing such a heat exchanger housing, for example. It should be noted in this context that for the purposes of the present invention, the thermal conductivity in the temperature range relevant for the operation of a heat exchanger assembly constructed in this way, for example in the range of -50 ° C to + 250 ° C in that region in which the recesses 60 are provided in the heat exchanger housing, can be considered.

At least a portion of the thermal insulating material in at least one recess may be provided as solid state material. This can, for example, porous or cell-like, for example as a foam material, eg PU foam or silicone foam, be provided, which contains air in its interior volume area. It is also possible that the sealing element 75 overlapping the recesses 60 or at least part of the recesses 60 is formed with material sections engaging in at least one of the recesses 60, preferably each recess 60 covered thereover, for providing the insulating material.

It is understood that in the structure according to the invention in addition to the recesses shown in the figures in the building material of a heat exchanger housing can also be provided at other areas or in other directions, for example, radially outwardly open, advantageously also completed by a closing element recesses.

Claims (10)

1. Heat exchanger arrangement, in particular for a vehicle heating device, comprising:

   - a pot-like internal heat exchanger housing (12) with a first bottom wall (18) in a first axial end region (16) of the heat exchanger arrangement (10) and a first circumferential wall (20) connected to the first bottom wall (18) surrounding a longitudinal axis (L),

   - a pot-like external heat exchanger housing (14) with a second bottom wall (22) in the first axial end region (16) of the heat exchanger arrangement (10) and a second circumferential wall (24) connected to the second bottom wall (22) surrounding the longitudinal axis (L), wherein in a second axial end region (26) of the heat exchanger arrangement (10), the internal heat exchanger housing (12) and the external heat exchanger housing (14) are connected to each other,

   - a fluid flow space (34) formed between the internal heat exchanger housing (12) and the external heat exchanger housing (14), wherein at least in the second axial end region (26) of the heat exchanger arrangement (10) at least one recess (60) open to the outside is provided in the construction material of the internal heat exchanger housing (12) or/and in the construction material of the external heat exchanger housing (14), wherein at a front side (74) facing away from the bottom walls (18, 22) at least one recess (60) is open to the outside, substantially in the axial direction, wherein in the second axial end region (26), the internal heat exchanger housing (12) comprises a front wall (36) axially limiting the fluid flow space (34) and adapted in an annular form in the circumferential direction and a fluid inlet opening (40) into the fluid flow space (34) or/and a fluid outlet opening (44) out of the fluid flow space (34),

   characterized in that in the region of the fluid inlet opening (40) or/and in the region of the fluid outlet opening (44) the fluid flow space (34) extends beyond the front wall (36) in the axial direction.
2. Heat exchanger arrangement according to claim 1,
   characterized in that a plurality of recesses (60) is provided, succeeding each other in the circumferential direction about the longitudinal axis (L), or/and in that at least one, preferably each recess (60) is curved about the longitudinal axis (L) or/and is straight in the circumferential direction.
3. Heat exchanger arrangement according to one of claims 1 or 2,
   characterized in that an exhaust gas outlet opening (48) is provided, leading out of an exhaust gas flow space (50) surrounded by the internal heat exchanger housing (12).
4. Heat exchanger arrangement according to claim 1, 2 or 3,
   characterized in that at least one recess (60) provided in the circumferential region of the fluid inlet opening (40) or/and at least one in the circumferential region of the fluid outlet opening (44) or/and at least one in the circumferential region of the exhaust gas outlet opening (48) is at least in some regions less deep than a recess (60) provided in a circumferential region substantially not overlapping the fluid inlet opening (40) or/and the fluid outlet opening (44) or/and the exhaust gas outlet opening (48).
5. Heat exchanger arrangement according to one of claims 1 to 4,
   characterized in that in the second axial end region (26), the internal heat exchanger housing (12) comprises a third circumferential wall (30) passing over the second circumferential wall (24) at its outside and connected to the latter.
6. Heat exchanger arrangement according to one of claims 1 to 5,
   characterized in that at least one recess (60) is closed by a closing element (75).
7. Heat exchanger arrangement according to one of claims 1 to 6,
   characterized in that in at least one recess (60), preferably in each recess (60), an isolating material is provided which has a lower heat conductivity than the construction material of the heat exchanger housing (12,14) comprising said recess (60).
8. Heat exchanger arrangement according to claim 7,
   characterized in that the isolating material substantially fills the at least one recess (60) completely.
9. Heat exchanger arrangement according to claim 7 or 8,
   characterized in that the isolating material substantially comprises air or/and a foamed material.
10. Heat exchanger arrangement according to one of claims 1 to 9,
    characterized in that the construction material of at least one heat exchanger housing (12,14) comprising a recess (60) comprises a metal material, preferably aluminium.

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