WO2006056189A1

WO2006056189A1 - Heat exchanger for an air heating device and method for producing a heat exchanger

Info

Publication number: WO2006056189A1
Application number: PCT/DE2005/002124
Authority: WO
Inventors: Andreas Ludwig
Original assignee: Webasto Ag
Priority date: 2004-11-26
Filing date: 2005-11-23
Publication date: 2006-06-01
Also published as: EP1815193A1; CA2595209A1; US20080093063A1; DE102005053517A1; JP2008521666A

Abstract

The invention relates to a heat exchanger (10) for an air heating device (12) which is integrated into a housing which guides air. Said heat exchanger comprises a heat exchanger body (14) which is provided with a longitudinal axis. According to the invention, the heat exchanger body (14) comprises, on the external side thereof, a plurality of corrugated ribs (28) which extend, essentially, along the periphery thereof, and which are provided on the surfaces of the heat exchanger.

Description

Heat exchanger for an air heater and method of manufacturing a heat exchanger

The invention relates to a heat exchanger for an air heater for integration into an air-conducting housing, which has a heat exchanger body with a longitudinal axis auf¬.

The invention further relates to various methods for producing a heat exchanger for an air heater for integration into an air-conducting housing, in particular a housing of a vehicle air conditioner, wherein the heat exchanger has a heat exchanger body with a longitudinal axis aufwei¬ send heat exchanger core and heat transfer surfaces up.

At present, fuel-operated auxiliary heaters for vehicles, in particular for commercial vehicles, are mainly installed separately from the vehicle's own heating / air-conditioning unit, also referred to herein as a vehicle air-conditioning unit. Der¬ like additional heaters are, for example, realized as Luftheizge¬ devices that are used as auxiliary heater and / or as Standheizun¬ conditions.

For quite some time efforts have been made to integrate air heaters in the vehicle's own heating-air conditioning unit. This saves space and required components. An example of such an arrangement is shown in DE 102 11 591 A1. The position selected for the integration of the air heater into the heating / air-conditioning unit and the construction of the air-heating appliance are decisively responsible for the function, economy and security of the integration. It is therefore desirable to identify the various associated with the introduction of the air heater in the heating-air conditioning unit problems and provide related solutions, so that ultimately a successful overall concept is available.

One problem is related to the high weight of the heat exchanger body, which is generally produced by a pressure casting technique. Due to the high weight, in particular, the housing carrying the vehicle heater must be designed to be correspondingly stable.

The longitudinally extending Wärmetau¬ shear in the axial direction is to be flowed around in the proposed concepts perpendicular to this direction. Such a flow inevitably leads to high Luftverwirbelungen and thus high flow losses. If this is to be compensated by an enlargement of the installation space which is unbound by the heat exchanger, then this has the consequence that overall the installation space for the heating air conditioning system has to be increased. Therefore, solutions are required which favor the flow behavior and the heat transfer of the heat exchanger.

Furthermore, there is a desire to be able to continue to use existing components of the air heaters in connection with the concept of installing the air heater in a heating air conditioning. One is therefore anxious, the To build as variable as possible heat exchanger so as to be able to use diesel¬ ben concepts in connection with different types of air heaters. This desire for variability also relates to the production of the heat exchanger.

In addition to the flow around the heat exchanger from the air to be heated by it, the heat transfer from the combustion gases to the heat exchanger furthermore plays an important role. This heat transfer should also be improved, in order to be able to thereby provide, in particular, greater freedom in the construction of the heat exchanger.

Another important requirement for an air heater is to arrange it so that a passage of combustion gases is excluded in the air flowing around the air heater. Furthermore, it is to be ensured that the air used for the combustion is taken from the outer region of the motor vehicle, that is to say, in particular, not from the interior. An improvement with regard to the location of the various connecting pieces of the air heater is also desirable.

The invention is based, at least in part, to overcome the abovementioned problems by appropriate solutions, in particular with regard to the flow behavior and the heat transfer.

This task is solved with the features of the independent claims. Advantageous embodiments of the invention are indicated in the dependent claims.

The invention builds on the generic heat exchanger in that the heat exchanger body on its outer side has a plurality of substantially along the circumference extending corrugated fins that provide heat transfer surfaces available. The corrugated shape of the ribs improves the heat transfer from the heat exchanger to the air to be heated, which flows through the spaces between the ribs, in particular due to the enlargement of the surface area available for the heat transfer. Furthermore, the ribs obtained by the corrugated shape increased stability.

On the one hand, it is possible in this context that the heat exchanger body has a heat exchanger core and that the plurality of corrugated fins is at least partially applied to the heat exchanger core by means of a separate component or as separate components. This separate production possibility is considered to be advantageous against the background of a possible weight reduction and a higher variability with regard to the design of the components and the production methods.

On the other hand, it is also conceivable that the Wärmetau¬ shear body has a heat exchanger core and that the plurality of corrugated fins is at least partially einstü¬ ckig formed with the heat exchanger core.

Usefully, it is provided that the plurality of corrugated fins shrunk onto the heat exchanger core and / or pressed on. It makes sense not to fasten such heat transfer surfaces to the heat transfer core via screw connections or similar connections, but rather by welding, soldering, shrinking or pressing on one or more pushed-on surface parts or entire packages.

The invention is based on the generic method da¬ by the fact that the Wärmetauscherkörperan on its outer side has a plurality of substantially along the circumference extending corrugated fins, which provide Wärmeübertra¬ gerflächen available, the Wärmetauscher¬ core and the corrugated fins at least partially be made separately. In this way, the advantages and particularities of the heat exchanger according to the invention are also realized in the context of a method.

This is usefully designed so that the corrugated ribs are shrunk and / or pressed onto the heat exchanger core. While the heat exchanger head and the heat exchanger base are preferably connected in a gas-tight manner to the heat exchanger core by welding, soldering, gluing and / or screwing, it is possible for the individual heat exchanger surfaces, which are of disk-like design, to be shrunk or pressed onto the heat exchanger core , whereby a further possibility for the variation of the production methods is available.

On the other hand, the invention also builds on the generic method in that the heat exchanger body on its outer side a plurality of essentially along the circumference extending corrugated fins auf¬ has, provide the heat exchanger surfaces available, the heat exchanger core and the heat exchanger surfaces are made in one piece.

The special features with regard to the configuration of the heat exchanger surfaces can be combined with numerous other properties of the heat exchanger, of air heaters for which the heat exchanger is provided, and of manufacturing processes for heat exchangers, so that advantageous properties result.

It can be provided that the Wärmetauscherkδrper and the heat exchanger bottom are made separately. Such a multi-part design of the heat exchanger body increases the variability with regard to possible structural variants as well as with regard to possible production methods. In particular, by manufacturing the heat exchanger bottom separately from the heat exchanger core, it is possible to use additional manufacturing methods for the heat exchanger core. With a suitable choice of the manufacturing process can thereby reduce the weight of the heat exchanger.

For comparable reasons, it makes sense that a separately manufactured heat exchanger head is provided. If such a heat exchanger head is present, the separate production makes sense. Depending on the geometric design of the burner head or the burner unit, however, it is also possible to completely dispense with the heat exchanger head. It is possible that the heat exchanger core is manufactured as diecasting part. Although such a die-cast part is comparatively heavy, it is comparatively inexpensive to manufacture on the other hand.

Usefully, it is provided that the heat exchanger core has an inner profile. By such an inner profile, the heat-transmitting inner surface of the heat exchanger can be increased, so that in turn the total space can be reduced in total.

It can be provided that the heat exchanger core is manufactured in an extrusion molding process. On the basis of such an extrusion process, the wall thicknesses of the heat exchanger can be selected to be lower in comparison to diecasting processes, in particular due to non-demanding draft angles, so that the total weight can be reduced. Thinner internal ribbing can also be provided in comparison to diecasting, so that in turn an enlarged heat-transmitting inner surface is provided. As part of the extrusion process, it is possible to integrate in the extruded profile, the geometry for Be¬ consolidation of heat exchanger head, burner, Wärmetauscherbo¬ the etc., for example in the form of core holes for holes.

It can be provided that it has a cross-sectional geometry which promotes the reduction of the flow resistance.

This can be achieved, for example, in that the cross-sectional geometry is oval. Another possibility is that the cross-sectional geometry of the cross-sectional geometry of an aircraft wing is similar.

Furthermore, it may be advantageous for the cross-sectional geometry to be spindle-shaped.

It can be provided that the heat exchanger body has on its outer side a plurality of rods which provide heat transfer surfaces available. By means of such a multiplicity of bars, a very large surface can be made available for heat transfer to the air to be heated.

On the one hand, it may be useful for the heat exchanger body to have a heat exchanger core and for the plurality of rods to be applied at least partially to the heat exchanger core by means of a separate component.

On the other hand, it is also possible for the heat exchanger body to have a heat exchanger core and for the plurality of rods to be formed at least partially in one piece with the heat exchanger core. Depending on the design of the rods on a separate component or in one piece with the heat exchanger core, different advantages can be recognized, for example on the one hand with regard to variability and on the other hand with regard to the simplicity of the overall manufacturing process.

It may be provided that the heat exchanger body is constructed from a plurality of heat exchanger body modules. Also This in turn increases the variability, since differently structured and, in particular, different sized heat exchangers can be produced from individual heat exchanger body modules.

Particular advantages can be observed in that the heat exchanger body modules are manufactured in a die casting process. If you do not want to deviate from the production of the heat exchanger in the conventional die-casting process, the modular production offers advantages, since only short and thereby less demanding draft angles are erforder¬ Lich.

With regard to the modular production, it is furthermore advantageous that the heat exchanger body modules are at least partially identical. There are then, especially in the case of the die-casting process, no different tools required.

It can be provided that the heat exchanger body is at least partially manufactured in a pressure casting process using two cores, the cores being removed in opposite demolding directions. As a result, the maximum thickness of the Entformungsschrägen can be reduced, resulting in a weight saving.

Further advantages result in connection with an air heater for integration into an air-conducting housing, with a heat exchanger, which has a heat exchanger body, wherein the air heater has flow guide elements which during combustion in an at least partially arranged in the interior of the heat exchanger combustion chamber direct the resulting hot gases to the inside of the heat exchange body. The resulting during combustion hot gases can be distributed more efficiently on the inside of the heat exchanger.

In this context, it is useful that the flow guide elements are designed in the manner of a screw thread, as blades, meander-shaped components, baffles and / or perforated tubes. These and many other possibilities improve the overall heat transfer.

Also, there are advantages in connection with an air heater for integration into an air-conducting housing, with a heat exchanger, wherein a flange plate is provided by means of sealing elements between a Montagestel¬ le for the air heater and the flange plate and zwi¬ tween the air heater and the Flange plate at least ei¬ ne exhaust discharge seals against the vehicle interior. Such a flange plate ensures that the exhaust gas can be conducted to the outside air as short a path as possible, whereby there is no danger of exhaust gases entering the interior of the vehicle.

In this context, it is also useful that the flange plate seals a combustion air supply against the Fahrzeugin¬ nenraum. Thus, it can be ensured that the combustion air is taken from the exterior of the vehicle.

Furthermore, it is advantageous that the flange plate has a passage for a fuel supply. Thus, all connections through which gases and liquids are transported are located in the area of the flange plate. What advantages for the connection of the air heater to the overall concept with it brings.

The invention is based on the finding that an air heater can be integrated into a heating air conditioning system of a motor vehicle, in particular of a commercial vehicle, in an economical manner which is suitable with regard to functionality. This can be attributed in particular to the positive properties of the heat exchanger with regard to the flow and heat transfer behavior.

The invention will now be described by way of example with reference to the accompanying drawings by way of particularly preferred embodiments.

Showing:

Figure 1 is a perspective view of a Luftheiz¬ device;

Figure 2 is a perspective view of a Luftheiz¬ device without heat exchanger;

FIG. 3 shows a perspective view of an air heater without heat exchanger, disassembled into burner head and burner unit;

FIG. 4 is a perspective view of a heat exchanger;

Figure 5 is a perspective view of individual compo nents a heat exchanger; FIG. 6 is a perspective view of an air heater with a housing attachment arranged thereon;

Figure 7 is a sectional view of a heat exchanger core with an oval cross-section;

FIG. 8 shows a sectional view of a heat exchanger core with a wing-shaped cross section;

Figure 9 is a sectional view of a heat exchanger core with spindle-shaped cross-section;

Figure 10 shows a heat exchanger and a separate component for heat transfer in perspective Darstel¬ development;

11 shows a heat exchanger in perspective view;

FIG. 12 shows a heat exchanger in perspective illustration;

13 shows a heat exchanger in perspective Darstel¬ development;

FIG. 14 is a perspective view of a plurality of identical heat exchanger body modules;

Figure 15 is a cutaway perspective view of a heat exchanger; FIG. 16 shows a perspective view of a combustion tube;

FIG. 17 shows a perspective view of a combustion tube;

Figure 18 is a perspective view of a Brennroh¬ res; and

FIG. 19 is a perspective view of a connection area of an air heater with flange plate.

In the following description of the drawings, the same reference numerals denote the same or similar components.

1 shows a perspective view of an air heater 12. The air heater 12 comprises a heat exchanger 10, which is mounted on a burner unit 60, and a burner head 62. The burner head 62 includes a blower motor 64 and a control unit 66, the essential components a combustion air blower unit 68 form. At the burner head 62, a nozzle 56 is further provided for a Brenn¬ air supply. On the burner unit 60 ei¬ ne fuel supply 58 and a nozzle 54 are provided for a Ab¬ gas discharge. A flange plate 48, which has openings for the passage of the fuel feed 58 and the combustion air supply 56, is disposed on the exhaust gas discharge 54. The function of the flange plate 48 will be explained in more detail with reference to FIG. The on the Nereinheit 60 patch heat exchanger 10 has on its outer side a rib structure, thereby increasing the area for heat transfer to the heat exchanger 10 flowing around the air. The air heater 12 is preferably angeord¬ net so with respect to the air flow of the air to be heated, that the air flows in and out perpendicular to the axis of the heat exchanger 10 and the heat exchanger 10 flows um¬.

Figure 2 shows a perspective view of an air heater 12 without heat exchanger. In this illustration, the burner head 62 and the burner unit 60 are to be recognized. The burner unit 60 comprises a burner tube 70, in which hot gases are produced by flame formation, which transfer their heat energy to the heat exchanger 10, not shown in FIG. In order to allow the hot gases to reach the heat exchanger, a plurality of holes 72 are formed in the shell of the burner tube 70.

FIG. 3 shows a perspective view of an air heater 12 without a heat exchanger, disassembled into the burner head and burner unit. It is clear from this representation that the burner head 60 is connected to the burner unit 60 via a flange connection 74, 76. Furthermore, it becomes clear in this representation that the flange plate 48 is firmly connected to the exhaust gas outlet 54, while a passage in the flange plate is provided for the combustion air feed 56.

FIG. 4 shows a perspective view of a heat exchanger 10. A rib structure can be seen, which provides heat transfer surfaces 22. Figure 5 shows a perspective view of individual components of a heat exchanger 10. It can be seen that the heat exchanger 10 is designed in several parts. It comprises a heat exchanger core 20, components 24 with heat exchanger surfaces 22, a heat exchanger base 16 and a heat exchanger head 18. Depending on the design of the burner head 62 and / or the burner unit 60, the heat exchanger head 18 may be dispensable. Within the heat exchanger core 20, an inner profile 30 is provided in order to improve the heat transfer from the hot gases arising in the burner tube 70 to the heat exchanger 10. The heat exchanger head 18 and the heat exchanger base 16 can be produced by various techniques, for example by deep drawing, die casting or by machining. The individual parts can then be connected to one another by various connecting techniques, for example by welding, soldering, gluing and / or screwing. Since combustion gases occur within the heat exchanger 10, it is essential that a gas-tight connection is provided between heat exchanger head 18, heat exchanger core 20 and heat exchanger bottom 16. In the context of the present disclosure, the heat exchanger core with components 24 fastened thereto with heat transfer surfaces 22 is also referred to as heat exchanger body 14.

FIG. 6 shows a perspective view of an air heater 12 with a housing fastening 74 arranged thereon. By means of this housing fastening 74, the air heater 12 can be fastened to a surrounding housing. The housing fastener 74 is above the heat exchanger Kopf 18 and the heat exchanger base 16 attached to the air heater 12.

FIG. 7 shows a sectional view of a heat exchanger core with an oval cross-section. The heat exchanger core 20 has an inner profile 30. The finer this inner profile 30 is ausgestal¬ Tet, the larger the surface, which is for a heat transfer from the hot gases to the heat exchanger 10 is available. A heat exchanger core 20, as shown here, can be produced, for example, by an extrusion process. As a result, small wall thicknesses can be ensured in order to ensure a low weight on the one hand and a large surface for the heat transfer on the other hand. In the heat exchanger core 20, fastening means, for example openings 76, are arranged for fastening the further components. The oval cross-sectional geometry 32 of the heat exchanger 20 can improve the flow conditions for the air flowing around the heat exchanger 20 to be heated. Since the heat exchanger base 16 is a component manufactured separately from the heat exchanger core 20, the production of the heat exchanger core 20 is simplified.

FIG. 8 shows a sectional view of a heat exchanger core with a wing-shaped cross-section. FIG. 9 shows a sectional view of a heat exchanger core with a spindle-shaped cross section. The cross-sectional geometries shown here, namely the flight-shaped cross-sectional geometry 34 and the spindle-shaped cross-sectional geometry 30, are to be understood as further examples of a geometry favorable for the flow around the heat exchanger 20. FIG. 10 shows a heat exchanger 10 and a separate component 24 for heat transfer in a perspective view. The illustrated component 24 is manufactured separately from the heat exchanger core 20. The components 24 already placed on the heat exchanger core 20 are fastened there by shrinking or pressing on individual or several pushed-on components 24 or entire packages.

FIG. 11 shows a heat exchanger in a perspective view. The heat exchanger 10 shown here has an extremely large surface area for the transfer of heat to the air flowing around it. This is realized in that the heat transfer surface 22 is provided by a plurality of rods 26.

FIG. 12 shows a heat exchanger in perspective view. Here, too, an extremely large heat transfer surface is available, since rods 26 are also provided in large numbers to provide this heat transfer surface 22. On the inside of the heat exchanger, in turn, an inner profile 30 can be seen. In the present embodiment, this inner profile partially continues the outer bars 26 or bar rows. The rods 26 both of the embodiment according to FIG. 12 and of the embodiment according to FIG. 11 can either be mounted externally on the heat exchanger surface by a separately produced component or can be realized by the subsequent processing of an extruded profile by means of reshaping or machining processes.

FIG. 13 shows a heat exchanger 10 in a perspective view. The components 28 shown here, the Heat exchanger surfaces 22 of the heat exchanger 10 provide for disposal, are corrugated fins that promote heat transfer.

FIG. 14 shows a plurality of identical heat exchanger body modules 38 in perspective view. The embodiment shown here is of particular interest if the heat exchanger is not to be produced by extrusion, as mentioned above, but, as usual, by a die casting process. Die casting methods have the disadvantage that large wall thicknesses can occur due to draft angles. In the present example, a plurality of heat exchanger body modules 38 are provided, wherein each individual heat exchanger body module 38 has only a small axial length. Consequently, wall thickness can be saved due to short Entungsungsschrägen.

FIG. 15 shows a cutaway perspective view of a heat exchanger 10. On the basis of this representation, a further method can be explained with which demolding slopes can be kept short. Namely, by making the heat exchanger 10 made as a die-cast part with two cores which are taken out in two opposite demolding plates 40, 42, the wall thickness can also be kept small.

FIGS. 16, 17, 18 show a perspective view of combustion tubes 70. FIG. 17 shows a perspective view of a combustion tube. FIG. 18 shows a perspective view of a combustion tube. In order to ensure that the hot gases produced during the combustion are heated to the inside of the heat exchanger in order to ensure good and uniform heat dissipation. It is useful to direct the hot gas by means of flow guiding parts within the heat exchanger 10 to the inner ribbing 30 or its inner wall, as efficiently as possible. FIG. 17 shows a helical flow-conducting part 44. Likewise, the flow guide part can be realized in the form of blades, meander-like geometries, baffles and perforated tubes, such a perforated tube having a plurality of holes 46 being shown in FIG. 18 in addition to the hole profile formed by the holes 72.

FIG. 19 shows a perspective illustration of a connection region of an air heater with a flange plate 48. The flange plate 48 serves to mount the air heater 10 to the vehicle body or to a housing or other component fastened to the vehicle. To ensure that the exhaust gases and the combustion air are supplied to the outer space or removed therefrom, the flange plate 48 is sealed against the air heater 12 and against the mounting location, that is to say the vehicle body, for example. The seals can be realized, for example, by means of sealing rings.

The features of the invention disclosed in the foregoing description, in the drawings and in the claims may be essential to the realization of the invention both individually and in any combination. LIST OF REFERENCE NUMBERS

10 heat exchanger 12 air heater

14 heat exchanger body

16 heat exchanger bottom

18 heat exchanger head

20 heat exchanger core 22 heat exchanger surface

24 components with heat transfer surfaces (disk-shaped)

26 components with heat transfer surfaces (rods)

28 components with heat exchanger surfaces (corrugated ribs)

30 inner profile 32 oval cross-sectional geometry

34 wing-shaped cross-sectional geometry

36 spindle-shaped cross-sectional geometry

38 heat exchanger body module

40 Entformungsrichtung 42 Entformungsrichtung

44 screw thread

46 holes in perforated tube

48 flange plate

54 exhaust system 56 combustion air supply

58 fuel feed

60 burner unit

62 burner head

Claims

1. Heat exchanger (10) for an air heater (12) for integration into an air-conducting housing, which has a Wär¬ metauscherkörper (14) with a longitudinal axis, da¬ characterized in that the heat exchanger body (14) on its outer side a A plurality of substantially along the circumference extending corrugated fins (28) which provide heat transfer surfaces available.

2. Heat exchanger (10) according to claim 1, characterized gekenn¬ characterized _/

- That the heat exchanger body (14) has a Wärmetauscher¬ core (20) and

the plurality of corrugated fins (28) is at least partially integral with the heat exchanger core (20).

3. Heat exchanger (10) according to claim 1, characterized gekenn¬ characterized

- That the heat exchanger body (14) has a Wärmetauscher¬ core (20) and the plurality of corrugated ribs (28) is at least partially applied to the heat exchanger core (20) by means of a separate component or as separate components.

4. Heat exchanger (10) according to claim 3, characterized gekenn¬ characterized in that the plurality of corrugated fins (28) shrunk onto the heat exchanger core and / or is pressed.

5. A method for producing a heat exchanger (10) for an air heater (12) for integration into an air leading der¬ housing, in particular a housing of a Fahrzeugklima¬ device, wherein the heat exchanger core a heat exchanger body (14) having a longitudinal axis having Wärmetauscher¬ (20) and heat exchanger surfaces, characterized ge indicates that the heat exchanger body (14) on its outer side a plurality of substantially along the circumference extending corrugated fins (28) which provide heat transfer surfaces available, wherein the heat exchanger core (20) and the corrugated ribs are at least partially made separately.

6. The method according to claim 5, characterized in that the corrugated ribs auf¬ shrinks on the heat exchanger core and / or pressed.

7. A method for producing a heat exchanger (10) for an air heater (12) for integration into an air-guiding housing, in particular a housing of a Fahrzeugklima¬ device, wherein the heat exchanger a heat exchanger body (14) having a longitudinal axis having heat exchanger characterized in that the heat exchanger body (14) on its outer side a plurality of substantially along the circumference extending corrugated fins (28), the heat exchanger surfaces provide, wherein the heat exchanger core (20 ) And the heat exchanger surfaces are made in one piece.