CA3029303C

CA3029303C - Combustion chamber module

Info

Publication number: CA3029303C
Application number: CA3029303A
Authority: CA
Inventors: Michael Humburg; Wolfgang Pfister
Original assignee: Eberspaecher Climate Control Systems GmbH and Co KG
Current assignee: Eberspaecher Climate Control Systems GmbH and Co KG
Priority date: 2018-01-08
Filing date: 2019-01-07
Publication date: 2021-06-15
Anticipated expiration: 2039-01-07
Also published as: CN110014804A; CA3029303A1; DE102018100216B3; CN110014804B; EP3508787A1; PL3508787T3; RU2705876C1; EP3508787B1

Abstract

A combustion chamber module for a fuel-powered vehicle heating device, comprising a combustion chamber housing (14) having a combustion chamber (28) defined by a circumferential wall (30) and by a flame tube (32) that follows the circumferential wall (30) in the direction of a housing longitudinal axis (L) and encloses a waste gas flow space (46) that is open in the direction of the housing longitudinal axis (L), wherein a waste gas backflow space (50) is formed between the flame tube (32) and a housing (12) surrounding the latter, wherein the waste gas flow space (46) is open towards the waste gas backflow space (50) in a first axial region (48) of the waste gas backflow space (50) and a catalytic converter arrangement (54) through which combustion waste gases flowing in the waste gas backflow space (50) may flow is provided in the waste gas backflow space (50), characterized in that a heating device (60) is provided for heating the catalytic converter arrangement (54).

Description

Combustion chamber module Description The present disclosure relates to a combustion chamber module for use in a fuel-powered vehicle heating device. The present combustion chamber module enables the burning of a fuel/air mixture to provide heat-transporting combustion waste gases in order to transmit this heat to a medium to be heated, for instance the air to be conducted into a vehicle interior or a liquid heat transfer medium circulating in a heat transfer medium circuit.
By providing the catalytic converter arrangement in the waste gas backflow space, in particular the CO portion and the HC portion in the combustion waste gases may be significantly reduced by the catalytic reaction occurring on the catalytic converter arrangement.
It is one object of the present invention to refine such a combustion chamber module such that the catalytic converter arrangement arranged in the waste gas backflow space can provide increased efficiency in the reduction of pollutants.
According to the invention, this object is attained using a combustion chamber module for a fuel-powered vehicle heating device comprising a combustion chamber housing having a combustion chamber defined by a circumferential wall and by a flame tube that follows the circumferential wall in the direction of a housing longitudinal axis and encloses a waste gas flow space that is open in the direction of the housing longitudinal axis, wherein a waste gas backflow space is formed between the flame tube and a housing enclosing the latter, wherein the waste gas flow space is open towards the waste gas backflow space in a first axial end region of the waste gas backflow space and a catalytic converter arrangement through which combustion waste gases in the waste gas backflow space flow is provided in the waste gas backflow space.
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- 2 -This combustion chamber module is distinguished in that a heating device is provided for heating the catalytic converter arrangement.
By providing a heating device associated with the catalytic converter arrangement, it is possible to operate the catalytic converter arrangement efficiently, not only during stationary operation, but also in a status in which essentially all system components of the combustion chamber module are brought to or maintained at operating temperature by the combustion waste gases flowing through them, and thus it is possible to reduce the CO and HC content in the combustion waste gases nearly to the detection limit and it is also possible to significantly reduce shut-off peaks in CO
and HC emissions that otherwise occur when a vehicle heating device constructed with such a combustion chamber module is shut off. On the contrary, with the inventive construction it is possible to heat the catalytic converter arrangement, in particular even at low ambient temperatures, even prior to or at the beginning of operation and to a temperature in the range of or greater than the light-off temperature of, for example, approximately 200C, or to maintain this temperature, until combustion initiates and the combustion waste gases flow through the combustion chamber module and also the catalytic converter arrangement, even without continued excitement of the heating device in the region of the catalytic converter arrangement, so that the temperature required for an efficient catalytic reaction is provided.
For very efficient operation of the heating device it is suggested that the latter be in heat-transfer contact, at least in regions, with the catalytic converter arrangement. In this way, direct heat transfer using thermal conduction to the catalytic converter arrangement is provided so that thermal losses may be prevented to the greatest extent possible.
In order to make the most efficient possible use of the installation space available in a heating device and in a combustion chamber module, the catalytic converter arrangement may be embodied annularly surrounding the housing longitudinal axis, and the heating device may have a heating region annularly surrounding the housing longitudinal axis.

- 3 -An embodiment providing compact and efficient operation of the catalytic converter arrangement may be attained in that heat transfer fins on the housing and projecting into the waste gas backflow space are provided and in that the catalytic converter arrangement is arranged in the waste gas backflow space following the heat transfer fins, or/and in that the catalytic converter arrangement is arranged in a second axial end region of the waste gas backflow space.
In order to be able to preheat, with the heating device, not only the catalytic converter arrangement, but also regions of the combustion chamber module immediately connected thereto, it is suggested that the heating region be arranged between the catalytic converter arrangement and the heat transfer fins and be in heat transfer contact with the catalytic converter arrangement and the heat transfer fins.
The catalytic converter arrangement may be axially supported in the direction of the first axial end region of the waste gas backflow space relative to the heat transfer fins.
Furthermore, defined positioning of the catalytic converter arrangement may be provided for in that the catalytic converter arrangement is axially supported in the direction from the first axial end region with respect to a combustion chamber housing support.
In order to be able to achieve thermal contact between the heating device and the catalytic converter arrangement positioned in the waste gas backflow space in a simple manner, it is suggested that a sealing arrangement sealing the waste gas backflow space gas-tight be provided, and that the sealing arrangement have a through recess for the heating device. This sealing arrangement may be arranged, for example, between the combustion chamber housing support and the housing.
The heating device preferably comprises an electrically excitable heat conductor.
Such an electrically excitable heat conductor, on the one hand, forms a compact and efficiently operable assembly that, on the other hand, may also be integrated into a combustion chamber module in a configuration that may be easily adapted to structural conditions in a versatile manner.

- 4 -The heat conductor may be a jacket heat conductor, for example. In such a jacket heat conductor, the jacket surrounding an interior heating element may be electrically coupled to the heating element and thus form a conductor region of the heat .. conductor.
The present invention furthermore relates to a vehicle heating device equipped with an inventively constructed combustion chamber module.
The invention shall be described in detail in the following with reference to the enclosed figures.
Fig. 1 is a longitudinal section of a combustion chamber module for a vehicle heating device;
Fig. 2 depicts, by itself, a housing of the combustion chamber module in Fig. 1 that provides a part of a heat exchanger arrangement;
Fig. 3 depicts a combustion chamber housing having a flame tube and a combustion chamber housing support;
Fig. 4 is a sectional depiction of a catalytic converter arrangement of the combustion chamber module in Fig. 1;
Fig. 5 depicts a heating device of the combustion chamber module in Fig. 1, seen from viewing direction V in Fig. 6;
Fig. 6 depicts the heating device in Fig. 5, seen from viewing direction VI in Fig. 5;
Fig. 7 depicts a sealing arrangement of the combustion chamber module in Fig. 1 constructed with two sealing disks;

- 5 -Fig. 8 depicts a sealing disk from the sealing arrangement depicted in Fig. 7, in viewing direction VIII.
Fig. 1 depicts a combustion chamber module for a fuel-powered vehicle heating device, labeled 10 in general. The combustion chamber module 20, depicted in Fig. 1 in a longitudinal section along a longitudinal center axis L of the combustion chamber module 10, comprises as essential components a housing 12, also depicted in longitudinal section in Fig. 2, and a combustion chamber housing 14, depicted in longitudinal section in Fig. 3.
The housing 12 depicted in Fig. 12 has a basically pot-like structure with a circumferential wall 16 and a base wall 18 attached thereto. Provided on the end region of the circumferential wall 16 removed from the base wall 18 is an annular fastening flange 20, engaging radially outward with respect to the longitudinal center axis L, on the circumferential wall 16. On the side facing an interior space 22 of the housing 12, heat transfer fins 24 extending for instance essentially in the direction of the longitudinal center axis L project from the circumferential wall 16. They extend starting from the base wall 18 nearly to the axial end region of the circumferential wall 16 on which the fastening flange 20 projects radially outward. Therefrom for instance heat transfer fins 26 continuing the heat transfer fins 24 may also be provided in the region of the base wall 18.
The housing 12, constructed from metal material, for example aluminum, for reasons of thermal stability, may form a part of a heat exchanger arrangement that may have, for example, another pot-like housing surrounding the housing 12, so that a flow space for a liquid heat transfer medium to be heated is formed between the housing 12 and this additional housing. Alternatively, the air to be heated and conducted into a vehicle interior may flow around the outside of the housing 12.
The combustion chamber housing 14 depicted in Fig. 3 provides, on the one hand, a circumferential wall 30 defining radially outward a combustion chamber 28, as well as a flame tube 32 connecting to the circumferential wall 30 and, in the example illustrated, embodied integrally with the latter. A flame diaphragm 34 is provided in

- 6 -the transition from the combustion chamber 28 or circumferential wall 30 to the flame tube 32. Provided on the exterior approximately in the region of the connection of the flame diaphragm 34 to the circumferential wall 30 or the flame tube 32 is a combustion chamber housing support 36 that provides a radially outwardly engaging fastening flange region 38.
Not depicted in Fig. 3 is a base assembly that is to be provided on the end region of the circumferential wall 30 axially removed from the flame tube 32 and that closes the combustion chamber 28 axially. A porous evaporator medium, for example, into which liquid fuel is fed and out of which the liquid fuel can exit into the combustion chamber 28 in vapor form may be provided on such a base assembly. An electrically excitable heater may be associated with such a porous evaporator medium in order to support fuel vaporization, in particular in the start phase of the combustion operation. Furthermore, the combustion air to be mixed with the fuel vapor for combustion may likewise be introduced via base assembly or base wall (not shown) or via an air inlet connector provided thereon. Alternatively or in addition, this combustion air may flow into the combustion chamber 28 via air inlet openings provided in the circumferential wall 30.
The circumferential wall 30 or the flame tube 32 embodied for instance integrally with the latter, the flame diaphragm 34, and the combustion chamber housing support may be made, for example, of metal sheet material.
Fig. 1 illustrates that when assembled the combustion chamber housing 14 is inserted into the housing 12 so that the two radially outwardly engaging fastening flange regions 20, 38 are axially adjacent to one another. Using stud bolts or the like (not shown) that pass through the fastening flange regions 20, 38, the combustion chamber module 10 may be joined to a housing that for instance also defines the air flow space leading to the combustion chamber 28. In order to achieve a sealed closure against the exit of waste gas in the bordering region of the combustion chamber housing support 36 to the housing 12, that is, in the region of the adjacently disposed fastening flange regions 20, 38, a sealing arrangement 44, depicted in

- 7 -detail in Figs. 7 and 8 and having two annular sealing disks 40, 42, is arranged between the two fastening flange regions 20, 38.
The sealing disks 40, 42 are preferably made of flexible, that is, deformable, and heat-proof material so that, with the appropriate introduction of force via the aforesaid stud bolts, the sealing disks 40, 42 may be clamped between the two fastening flange regions 20, 38, producing a sealed closure.
Fig. 1 illustrates that a waste gas flow space 46 that is open in the direction to the base wall 18 of the housing 12 is formed in the interior of the flame tube 32.
The combustion waste gases created during the combustion in the combustion chamber 28 flow along the waste gas flow space 46 towards the base wall 18 and there are diverted radially outward at the outlet out of the flame tube 32. The combustion waste gases then enter into a first axial end region 48 of a waste gas backflow space, generally labeled with 50, that is formed between the outside of the flame tube 32 and the circumferential wall 16 of the housing 12. The waste gases flow along the heat transfer fins 24 through the waste gas backflow space 50 and transmit heat to the housing 10 via the contact with the heat transfer fins 24 and the inner surface of the circumferential wall 16.
The combustion waste gases flowing in the waste gas backflow space 50 along the heat transfer fins 24 flow in the direction of a second axial end region 52 of the waste gas backflow space 50. In this second axial end region 52, the heat transfer fins 24 terminate and in the waste gas backflow space 50 a catalytic converter arrangement, labeled 54 in general, is provided. The catalytic converter arrangement 54, embodied e.g. in general as an oxidation catalytic converter, may be constructed with an annular support through which waste gas may flow and on the surface of which a catalytically acting coating be provided. For example, this support may be embodied porous or having a honeycomb-type structure in order to be able to provide a large catalytically active surface area. The catalytic converter arrangement 54, also shown in Fig. 4, has an annular structure adapted to the annular sectional geometry of the waste gas backflow space 50, so that the former may be positioned essentially without radial clearance between the flame tube 32 or the circumferential wall 30 of

- 8 -the combustion chamber housing 14 and the circumferential wall 16 of the housing 10. Towards the first axial end region 48 of the waste gas backflow space 50, the catalytic converter arrangement 54 may be axially supported on a radial expansion region 56 of the combustion chamber housing support 36 and thus may be held in a defined position. Towards the first axial end region 48, the catalytic converter arrangement 54 may be axially supported by the heat transfer fins 24 projecting inward from the circumferential wall 16 and thus may be held in a defined position.
For attaining this supporting interaction, an annular heating region 58 of an electrically excitable heating device, labeled 60 in general, may be arranged between the likewise annular catalytic converter arrangement 54 and the heat transfer fins 24.
The heating device 60 may be constructed, for example, with a heat conductor 62, wherein the heat conductor 62 may preferably be embodied as a jacket heat conductor. In such a jacket heat conductor, a thermally active heating element running in the interior thereof is surrounded by a likewise electrically conductive jacket, so that the jacket forms a conductive region of the heat conductor. In order to prevent an outward electrical short circuit, the exterior of this jacket may be covered with an electrically insulating material that is also, naturally, electrically insulating with respect to the heating element.
The heat conductor 36 may be curved into a circular configuration, in adaptation to the annular structure of the catalytic converter arrangement 54 and the waste gas backflow space 50, so that an end region 64 of the heat conductor 62 closes the annular structure. In this region, the heat conductor may be led out with a connection section, which first extends radially outward, then axially, and then radially outward again, from this region of the waste gas backflow space 50.
In order to provide defined positioning, in particular of the annular heating region 58, positioning depressions 66 that are axially open and that do not completely receive the heating region 58, are provided in the axial end regions of the heat transfer fins 24. For the heating region 58 received in the positioning depressions 66, the former projects axially over the heat transfer fins 24 so that there is direct heat transfer contact between the heating region 58 and the catalytic converter arrangement

- 9 -supported by it on the heat transfer fins 24. In the region of the heat transfer fin 24 illustrated at the top of Fig. 2, the positioning recess 66 is extended radially outward to the circumferential wall 16 in order to receive in this region the section 68 of the heat conductor 62 extending radially outward. For passing through the section 70 of the heat conductor 62, which is then connecting and essentially extends axially, in this circumferential region the catalytic converter arrangement 54 may have a corresponding recess that passes axially therethrough.
Figs. 7 and 8, in conjunction with Fig. 1, illustrate that the sealing arrangement 44 is configured such that the heat conductor 62 may be guided outwardly therethrough.
To this end, the sealing disk 42, which is immediately attached to the fastening flange region 20 and thus directly axially seals the waste gas backflow space 50, has a through opening 72 for the section 70 of the heat conductor 62 that extends essentially axially. An axially open recess 74 extends radially outward from the through opening 72 and axially opposes a corresponding axially and radially outwardly open recess 76 of the other sealing disk 40. Thus the heat conductor 62, with its radially extending section 78 that connects to the axially extending section 70, is held or received between the two sealing disks 40, 42 in the recesses 74, 76 of the same. Due to the flexibility of the sealing disks 40, 42 and the during the fastening of the housing 12 together with the combustion chamber housing support 36 by the aforesaid stud bolts, the two sealing disks 40, 42 are deformed such that they also enclose the heat conductor 62 passing through this region in a gas-tight manner. Due to the force exerted here on the housing 12, in particular also axially, the latter is caused to move towards the combustion chamber housing support 36 by the deformation of the sealing arrangement 44, which makes it possible to clamp the catalytic converter arrangement 54 in a defined position between the radial expansion region 56 of the combustion chamber housing support 36 and the heat transfer fins 24 of the housing 12 or the heating region 58 of the heating device 60 supported axially thereon.
Due to the provision of the heating device in association with the catalytic converter arrangement 54, it is possible to preheat the catalytic converter arrangement 54 at or prior to the start phase of the combustion operation by exciting the heating device 60,

- 10 -so that said catalytic converter arrangement, even at the beginning of the combustion, has a temperature that is greater than a light-off temperature and it is also provided in the start phase of the combustion operation that lower emission of pollutants may be attained, in particular by reducing the CO content and the HC
content in the waste gases. Since in the inventive embodiment it is not only the catalytic converter arrangement 54 that can be preheated through the heating region 58 of the heating device, but also the axial end regions of the heat transfer fins 24 supporting it, at the beginning of the combustion operation heat stored by the waste gas flowing through the waste gas backflow space 50 into the heat transfer fins 24 is carried to the catalytic converter arrangement 24 and thus is continued to be used efficiently for heating the catalytic converter arrangement 54.
Finally, it should be noted that structural changes may be provided, that contrast with the embodiment illustrated but adhere to the principles of the present invention.
Thus, for example, the heating region 58 of the heating device 60 may have a structure that differs from a precisely circular geometry. For example, the heating region 62 may be constructed with a plurality of windings that extend in a helical fashion or may extend with a wave-like or zig-zag structure about the longitudinal center axis. A wandering course in the circumferential direction and/or in the radial direction is also possible.
Furthermore, the catalytic converter arrangement 54, given a correspondingly shorter design of the heat transfer fins 24, could move closer to the first axial end region 58 of the waste gas backflow space 50, so that, for example, the catalytic converter arrangement 54 could be positioned approximately in a longitudinal center region of the waste gas backflow space 50. In principle even a plurality of such catalytically active arrangements could be provided following one another in the direction of flow, wherein in this case, for instance, such a heating device may be associated with one or a plurality of these catalytic converter arrangements. Other components, such as for example a hydrocarbon reservoir, may be provided, for example upstream of the catalytic converter arrangement in the waste gas backflow space.
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Claims

CLAIMS:

1. A combustion chamber module for a fuel-powered vehicle heating device, comprising a combustion chamber housing having a combustion chamber defined by a circumferential wall and by a flame tube that follows the circumferential wall in the direction of a housing longitudinal axis and encloses a waste gas flow space that is open in the direction of the housing longitudinal axis, wherein a waste gas backflow space is formed between the flame tube and a housing enclosing the latter, wherein the waste gas flow space is open towards the waste gas backflow space in a first axial end region of the waste gas backflow space and a catalytic converter arrangement through which combustion waste gases flowing in the waste gas backflow space may flow is provided in the waste gas backflow space, and a heating device for heating the catalytic converter arrangement, wherein heat transfer fins on the housing project into the waste gas backflow space, the catalytic converter arrangement being arranged in the waste gas backflow space following the heat transfer fins.

2. The combustion chamber module according to claim 1, wherein the heating device is in heat-transfer contact, at least in regions, with the catalytic converter arrangement.

3. The combustion chamber module according to claim 1 or 2, wherein the catalytic converter arrangement annularly surrounds the housing longitudinal axis, and in that the heating device has a heating region annularly surrounding the housing longitudinal axis.

4. The combustion chamber module according to any one of claims 1 to 3, wherein the catalytic converter arrangement is arranged in a second axial end region of the waste gas backflow space.

5. The combustion chamber module according to claim 3 or 4, wherein the heating region is arranged between the catalytic converter arrangement and CAN_DMS: \132976677\1 Date Recue/Date Received 2020-04-16 the heat transfer fins and is in heat transfer contact with the catalytic converter arrangement and the heat transfer fins.

6. The combustion chamber module according to claim 4 or 5, wherein the catalytic converter arrangement is axially supported in the direction of the first axial end region of the waste gas backflow space relative to the heat transfer fins.

7. The combustion chamber module according to any one of claims 1 to 6, wherein the catalytic converter arrangement is axially supported in the direction from the first axial end region with respect to a combustion chamber housing support.

8. The combustion chamber module according to any one of claims 1 to 7, wherein a sealing arrangement sealing the waste gas backflow space gas-tight is provided, the sealing arrangement having a through recess for the heating device.

9. The combustion chamber module according to claim 7, wherein a sealing arrangement sealing the waste gas backflow space gas-tight is provided, the sealing arrangement having a through recess for the heating device, and the sealing arrangement is arranged between the combustion chamber housing support and the housing.

10. The combustion chamber module according to any one of claims 1 to 9, wherein the heating device comprises an electrically excitable heat conductor.

11. The combustion chamber module according to claim 10, wherein the heat conductor is a jacket heat conductor.

12. A vehicle heating device comprising the combustion chamber module according to any one of claims 1 to 11.
CAN_DMS: \132976677\1 Date Recue/Date Received 2020-04-16