JP2002542446A - Combustion chamber of heating device - Google Patents

Abstract

(57) [Summary] The combustion chamber comprises a mixing and combustion zone (1) having an annular cross section between an outer flame tube (3) and an inner tube (2) arranged concentrically in the flame tube. And an inner tube is provided for introducing combustion air into the mixing and combustion zone (1) and has a peripheral wall with a plurality of openings (6) for this introduction. In the present invention, the opening (6) forms a porous microporous structure.

Description

DETAILED DESCRIPTION OF THE INVENTION

TECHNICAL FIELD The present invention provides an annular mixing and combustion zone between an outer flame tube and an inner tube concentrically disposed within the flame tube, wherein the inner tube comprises a mixing and combustion zone. The invention relates to a combustion chamber of a heating device, in particular for motor vehicles, of the type provided for introducing combustion air therein and having a peripheral wall provided with a plurality of openings for this introduction.

BACKGROUND OF THE INVENTION [0002] Heating systems for vehicles powered by fuel generally have a combustion chamber of the type described above, the flame tube of which is arranged in a heat exchanger connected to an exhaust conduit. The heat exchanger can be configured as a water heat exchanger or an air heat exchanger, so as to transfer combustion heat to a heated water stream or a heated air stream.

[0003] Normally, the inner pipe is configured as a so-called slit pipe, that is, the peripheral wall of the inner pipe has an elongated slit in the axial direction, and the combustion air introduced into the inner pipe while swirling is It enters the mixing and combustion zone from the inner tube through the slit.

[0004] Since it is desirable to make the heating device as compact as possible, efforts have been made to reduce the dimensions of the combustion chamber, but in conjunction with that, the axial length of the combustion chamber has been designed to be as short as possible. Must be done.

[0005] Despite its compact construction, in order to obtain high heating power, strong combustion must be achieved in a small space. In principle, of course, there is the danger of excitement of disturbing noises, and in particular in the case of compact structures, resonances can excite noises with particularly unpleasant vibrations. .

DISCLOSURE OF THE INVENTION [0006] The object of the present invention is to ensure particularly low noise generation during heating operation.

[0007] An aspect of the present invention for solving the above-mentioned problem is that in a combustion chamber of the type described at the beginning of the specification, the opening forms a wholly or partially porous microporous structure. .

[0008] The general idea underlying the present invention is that the total cross-sectional area of the opening in the inner tube peripheral wall is
Dividing into a number of very small openings that are closely adjacent to each other to form a relatively large area of a pore-like or lattice-like zone in the peripheral wall of the inner tube.

This makes it possible to achieve a significantly higher noise reduction.

[0010] This is because the combustion air flowing through the gas permeation zone of the inner pipe peripheral wall forms a relatively stable boundary layer on the outer surface side of this zone, and the boundary layer is formed in the mixing and combustion zone. It is based on the fact that flashback does not enter the inner chamber of the inner pipe even by the turbulence caused by the flow.

[0011] In addition, the porous or lattice-shaped peripheral wall stabilizes the temperature state outside the inner tube. This is because, based on the material forming the microporous structure, possible reductions in temperature fluctuations occur, and thus the formation of turbulence immediately outside the inner tube and thus turbulent backflow into the inner tube The possibility is also blocked.

According to an advantageous embodiment of the present invention, in order to obtain a stable temperature profile, the microporous structure can be made of a material having good thermal conductivity, especially a metallic material.

In a further advantageous embodiment of the invention, it is also possible to subject the microporous structure to a film-forming process in a contact-reaction manner, so that any fuel particles which have settled or adhered thereto can be rapidly reduced. Combustion air that is decomposed and passes through the microporous structure is rapidly supplied for combustion in the mixing and combustion zone.

[0014] Furthermore, in a particularly advantageous embodiment, it is also possible for each opening of the inner tube to have only a partially porous microporous structure. In this regard, the advantages that have proven advantageous are:
By providing a microporous structure in the front area of the opening inside the flame tube when viewed in the flow direction of the combustion air, and by providing a microporous structure in the outer area of the opening in the rear area in the flow direction of the combustion air, respectively. is there. In short, the microporous structure at the front opening is from the center of the inner tube each time,
It has a smaller spacing than the microporous structure at the rear opening.

In that case, by providing appropriate notches along the inner and outer perimeters, the inner surface of the inner microporous structure is positioned flush with the other inner walls of the inner tube while the outer micropores are located. Surface alignment of the outer surface of the structure with the outer peripheral surface of the inner tube is achieved.

In addition, regarding advantageous configuration means of the present invention, refer to the description of the claims and the detailed description of the drawings given below for particularly advantageous embodiments of the present invention.

BEST MODE FOR CARRYING OUT THE INVENTION Next, an embodiment of the present invention will be described in detail with reference to the drawings.

The air heating device shown in FIG. 1 has a mixing / combustion zone 1, which is provided between an inner tube 2 and a flame tube 3 concentrically surrounding the inner tube 2. It is formed as an annular chamber.

The inner tube 2 has a closed end on the right hand side and an open end on the opposite side as viewed in the drawing, at which the swirl pumped from the fan wheel 5 via the guide mechanism 4. Combustion air with a dynamic flow is blown into the inner pipe 2. The combustion air flows into the mixing / combustion zone 1 through an opening 6 formed in the peripheral wall of the inner pipe 2, and the structure of the opening 6 will be described later.

At the end of the flame tube 3 facing the fan wheel 5, the mixing and combustion zone 1 is closed by an end wall. A throttle 7 is arranged at the other end of the flame tube 3 extending axially beyond the inner tube 2, and through a central opening of the throttle, the mixing and combustion zone 1 is separated from the heat exchanger 8. It is connected to the room.

The inner wall of the portion of the flame tube 3 close to the fan car 5 or the wall region of the flame tube is coated with a wire fleece, which receives the supplied fuel in the form of a core, and furthermore, this wire The fuel evaporating from the fleece automatically burns in the mixing and combustion zone 1 under the supply of combustion air via the inner pipe 2.

Disposed on the side of the mixing and combustion zone 1 is a radial blind chamber 9 which houses a spark plug, not shown, by means of a fuel line 10 via a fuel plug. The supplied fuel can be ignited.

The combustion gases formed during the combustion are deflected on advection to the heat exchanger 8 and are led to an exhaust conduit 11, which is located on the side of the heat exchanger 8, as viewed in the drawing. It is located at the left end of the heat exchanger. The heat of the combustion gas when being guided to the exhaust conduit is converted into heat by the heat exchanger 8.
To the inner fin 12 and the inner fin 12.

The air flows along the outer surface of the heat exchanger 8, and the air flows from another fan wheel 13 to a casing 14 that surrounds the heat exchanger 8 and an external fin 15 of the heat exchanger 8. The air is blown through the casing 14 and is guided from the outlet of the casing 14 to an inner room of the automobile or the like to be heated.

The fan wheel 5 for combustion air and the fan wheel 13 for heated air are both driven by a common electric motor 16.

[0026] Unlike the embodiment shown, the heat exchanger 8 can also be surrounded by a water jacket, in which case the water is spiraled by a guide web (not shown) provided on the outer surface of the heat exchanger. The gas flows from the inlet to the outlet in a circulating manner, which is circulated through one or more heating elements (not shown) and / or a cooling circuit of the motor vehicle.

Incidentally, a special feature of the present invention resides in that an opening 6 is formed in the peripheral wall of the inner tube 2.

In order to form the opening 6, the peripheral wall of the inner tube 2 has a porous microporous structure zone.

This microporous structure is formed, for example, by a “closed” wire woven fabric, which is arranged along or in the opening of the peripheral wall of the inner tube 2, and Completely or partially.

For example, it is also possible to arrange an axial slit in the peripheral wall of the inner tube 2, and the axial slit is coated on the outer surface side and / or the inner surface side of the peripheral wall with the metal woven cloth. The metal woven fabric may also cover the entire outer peripheral surface and / or the entire inner peripheral surface of the inner tube 2 in some cases.

Instead of axial slits, openings of another shape, for example openings distributed in a grid,
For example, it is also possible to provide a circular opening, which is also coated on the outer and / or inner side of the inner tube with a woven wire fabric.

Instead of using a woven wire fabric, it is also possible to use a knitted wire fabric or a fine wire net.

[0033] Furthermore, it is also possible for the openings to be made of sintered metal, fiber metal or spongy metal.

Instead of the above metal structure, a porous ceramic can be used.

In some cases, the entire peripheral wall of the inner tube may be made of sintered metal, fiber metal, spongy metal or ceramic.

Incidentally, it is also possible to apply a film formation process to the above-mentioned porous microporous structure by a contact reaction method.

Since the opening 6 is configured as a zone having a porous microporous structure, the combustion air passing through the opening 6 from the inner chamber of the inner pipe 2 into the mixing and combustion zone 1 is formed in the inner pipe 2. A relatively stable boundary layer is formed on the outer surface side, and the boundary layer shields the inner pipe 2 and particularly the inner chamber of the inner pipe against turbulent flow in the mixing and combustion zone 1 during the combustion operation. So
Accordingly, generation of unpleasant noise is prevented.

Furthermore, by using a porous microporous structure, in particular, by using a metal material or a material having good heat conductivity for this microporous structure, a relatively stable temperature state is obtained near the peripheral wall of the inner tube 2. This also additionally prevents the formation of turbulence near the wall.

An advantage in the case of ceramic materials and other materials having a high heat capacity is that significantly higher temperatures which promote the reaction of the fuel can be tolerated, so that disturbances to the inner space of the inner tube 2 can result. Flame intrusion is likewise very effectively prevented.

By subjecting the porous microporous structure to film formation in a contact reaction manner, it is possible to particularly effectively prevent the formation of deposits composed of fuel residues and the like. Thus, it is ensured that the combustion air can pass through the opening 6 or the microporous structure forming the opening as desired, even under very unfavorable operating conditions.

A particular advantage of the present invention is that the desired noise reduction can be achieved without any other structural changes to the heating device.

In the embodiment shown in FIG. 2, each opening 6 of the inner tube 2 has only a microporous structure 17, 18 only in each area. In that case, the inner microporous structure 17 forms a cylindrical part, which is the left end of the inner tube where combustion air enters the inner tube 2 (see FIG. 2). Thus, the inner peripheral wall of the inner tube and one section of the opening 6 are covered. In this case, a notch or a cut-out portion is provided on the inner periphery of the inner tube 2, and the inner peripheral surface of the microporous structure 17 extends in the axial direction to the right in FIG. The surface is aligned.

The outer microporous structure 18 also forms a cylindrical part, which has a larger diameter than the inner microporous structure 17 and the inner tube 2 Is arranged so as to partially cover the opening 6 outside. Even with this inner micropore structure, the outer peripheral surface of the outer micropore structure 18 can be surface-aligned with the remaining outer peripheral surface of the inner pipe 2 by reducing the outer peripheral surface of the inner tube 2, that is, by cutting off the material. Guaranteed.

As shown in the figure, a zone having no micropore structure can be provided between the inner micropore structure 17 and the outer micropore structure 18 as viewed in the axial direction. The opening 6 is completely open in this area.

The inner and outer microporous structures 17, 18 not only reduce the effective cross-sectional area of the opening 6. Rather, the inner and outer microporous structures 17, 18 also form an enhanced roughened area on the inner or outer surface of the inner tube 2, so that the combustion air flowing through the inner tube or the inner surface of the inner tube 2 flows therethrough. The generated combustion air generates a boundary vortex layer with high intensity, and thus,
The free cross-section used for the flow of combustion air inside and outside the inner tube is reduced by the hydrodynamic effect, and the flow velocity of the combustion air is increased in the remaining cross-section.

In a particularly advantageous embodiment, it is also possible for the inner micropore structure 17 and / or the outer micropore structure 18 to each be radially spaced from the peripheral wall of the inner tube 2. In that case, each micropore structure itself is configured as a cylindrical portion, and is held by a cam-shaped projection provided on the peripheral wall surface of the inner tube 2 or integrally formed. Such an arrangement is possible even if only a single cylindrical microporous structure is provided which can completely cover the opening 6.

By arranging the microporous structure away from the inner tube 2, particularly in the case of a microporous structure arranged on the outer surface side of the inner tube 2, the microporous structure can be heated relatively quickly to a very high temperature. Become. This is because relatively little heat of the flame burning in the flame tube 3 is transferred to the inner tube 2. The high temperature particularly effectively prevents coking of the microporous structure.

[Brief description of the drawings]

FIG. 1 is a schematic cross-sectional view of a heating device including a combustion chamber configured according to the present invention.

FIG. 2 is a sectional view of an inner tube.

[Explanation of symbols]

1 mixing and combustion zone, 2 inner tube, 3 flame tube, 4 guide mechanism,
5 Fan Car for Combustion Air, 6 Opening, 7 Restrictor, 8 Heat Exchanger, 9 Blind Chamber, 10 Fuel Conduit, 11 Exhaust Gas Conduit, 12 Internal Fin, 13 Fan Car for Heated Air, 14 Casing, 15
External fins, 16 electric motors, 17 inner micropore structure, 18
Outer micropore structure

[Procedural Amendment] Submission of translation of Article 34 Amendment

[Submission date] April 12, 2001 (2001.4.12)

[Procedure amendment 1]

[Document name to be amended] Statement

[Correction target item name] Claims

[Correction method] Change

[Contents of correction]

[Claims]

──────────────────────────────────────────────────の Continued on the front page (72) Inventor Günter Ebersbach, Germany Wolfschlugen Seestrasse 9 F-term (reference) 3K017 BA08 BB07 BC02 BC03 BC04 BC07 BC09 BE03 BE10 DD01 DD03 3K023 FA01 FA04

Claims (12)

[Claims] 1. An annular mixing and combustion zone between an outer flame tube and an inner tube concentrically disposed within the flame tube, wherein the inner tube directs combustion air into the mixing and combustion zone. In the combustion chamber of a heating device for motor vehicles, in particular of the type provided for introduction and having a peripheral wall provided with a plurality of openings for this introduction, the opening (6)
A combustion chamber of a heating device, characterized in that it forms a porous microporous structure (17, 18) in whole or in part. 2. The combustion chamber according to claim 1, wherein the end of the inner tube projecting into the flame tube has at least a substantially closed end-side bottom. 3. The flame tube (3) has an end portion of the inner tube (2) which continues beyond an end located in the flame tube, and a heat exchanger (8) is provided on the end face side of the end portion. 3. The combustion chamber according to claim 1 or 2, wherein an opening leading to ()) is provided. 4. The combustion chamber according to claim 1, wherein the porous microporous structure forming the opening is formed as a metal woven fabric or a metal knitted fabric. 5. A method according to claim 1, wherein the porous microporous structure forming the openings consists essentially of spongy metal and / or fiber metal and / or sintered metal. Combustion chamber. 6. A combustion chamber according to claim 1, wherein the porous microporous structure forming the openings consists essentially of a porous ceramic. 7. The combustion chamber according to claim 1, wherein a film formation process is performed on the porous microporous structure in a contact reaction manner. 8. The method according to claim 1, wherein the combustion air is introduced into the inner pipe with a swirling flow.
The combustion chamber according to any one of the preceding claims. 9. An opening (6) having a microporous structure (17) in the area of the inner surface of the inner tube (2).
9. The combustion chamber according to claim 1, wherein the combustion chamber comprises: 10. An opening (6) having a local microporous structure (1) on the outer surface of the inner tube (2).
The combustion chamber according to any one of claims 1 to 9, comprising (8). 11. The inner surface of the inner microporous structure (17) is flush with the boundary inner surface of the inner tube (2) and / or the outer surface of the outer microporous structure (18) is of the inner tube (2). The combustion chamber according to claim 9, wherein the combustion chamber is in plane alignment with the outer boundary surface. 12. The combustion chamber according to claim 1, wherein the microporous structure is radially spaced from a peripheral wall of the inner tube.