EP0714493A1

EP0714493A1 - Burner for a vehicle heating device

Info

Publication number: EP0714493A1
Application number: EP94926881A
Authority: EP
Inventors: Herbert Langen; Fritz Mohring; Stefan Ottenbacher; Wolfgang Schaffert
Original assignee: J Eberspaecher GmbH and Co KG
Current assignee: Eberspaecher Climate Control Systems GmbH and Co KG
Priority date: 1993-08-26
Filing date: 1994-08-25
Publication date: 1996-06-05
Also published as: CZ285670B6; CZ319595A3; CN1125477A; WO1995006223A1; DE4328789A1; DE4328789C2; US5707227A

Abstract

A burner is disclosed for a vehicle heating device having (a) a fan (8) for supplying combustion air; (b) a combustion chamber (2) provided on part of its inner surface with a lining (36, 38) which is porous in at least certain areas; (c) an arrangement (6, 54) for supplying fuel to the porous area of the lining (36, 38); and (d) an electric heater plug (4) for igniting the fuel evaporated through the lining. The burner is characterised in that (e) the end area (14) of the combustion chamber (2) opposite to the hot gas outlet is designed with a substantially cylindrical wall (20) and a bottom (22); (f) the lining (38) covers the bottom (22) of the combustion chamber and at least part of the adjacent longitudinal wall (20) of the combustion chamber; (g) the heating area (44) of the heater plug (4) is arranged in a recess (50) of the lining (36, 38) in communication with the inside of the combustion chamber (2) through an open passage (52).

Description

Burner of a vehicle heater

The invention relates to a burner of a vehicle heating device, which has:

(a) a fan for supplying combustion air; (b) a combustion chamber which has a

Has lining that is at least partially porous;

(c) means for supplying fuel to the porous region of the liner;

(d) and an electric glow plug for igniting the fuel evaporated from the lining or the fuel-air mixture.

With such burners, the position of the glow plug for the ignition is very important.

The invention has for its object to design the burner in such a way that favorable ignition conditions result on the one hand and that on the other hand the glow plug is protected against impairments due to the conditions prevailing in the combustion chamber, in particular with regard to flame exposure and contamination.

To achieve this object, the burner is characterized according to the invention in that

(e) that the end region of the combustion chamber opposite the hot gas outlet is formed with a substantially cylindrical wall and a combustion chamber base;

(f) that the lining is provided for the combustion chamber floor and at least a part of the length of the combustion chamber wall adjoining it; (g) that the glow plug glow area in a recess space of the

Lining is arranged, the recess space over a open transition communicates with the interior of the combustion chamber.

Characterized in that the glow plug is positioned in a recess space of the lining, evaporation of

Fuel in the immediate vicinity of the annealing area, an ignitable fuel-air mixture. Since the glow plug glow area is not simply freely inside the combustion chamber, it is removed from the inside of the combustion chamber from the direct effect of impairments of the type mentioned. In addition, the burner is particularly inexpensive to manufacture with regard to the environment of the glow plug.

The open transition between the recess space and the interior of the combustion chamber should be so large that the ignition of the fuel-air mixture can spread well into the interior of the combustion chamber.

On the other hand, the transition should not be too large in order to deliberately protect the recess area. The open transition preferably has a cross-sectional area that is 0.5 to 10%, preferably 1 to 5%, of the area of the combustion chamber base.

Particularly favorable conditions with regard to manufacture and with regard to the position of the glow area of the glow plug result if the glow plug is arranged essentially in the tangential direction relative to the combustion chamber wall. However, this type of arrangement is only a preferred one; others are possible without being a poorer solution to the task.

The lining preferably has a combustion chamber base lining part and an essentially cylindrical combustion chamber wall lining part adjoining it with an end face. A particularly favorable material for the combustion chamber floor lining part is metal web or metal mesh; a particularly favorable material for the combustion chamber wall lining part is ceramic. The recess space can be formed particularly cheaply in that the combustion chamber base lining part is not completely - disc-shaped, but in comparison has no lining material in a limited area of the disc. This material omission best starts from the edge of the combustion chamber floor lining part. However, it is also possible to use material of the combustion chamber wall instead or in addition

To leave out the lining part.

Preferably, the open transition - viewed in the axial direction of the combustion chamber end region - is essentially circular. This is the geometric relationships of the

Combustion chamber end area is particularly well adapted and enables particularly simple production.

A glow plug, sometimes also called a rod candle, is preferably provided as the glow plug. In contrast to the more conventional glow plugs, glow plugs have one more coated filament. The essentially cylindrical glow plug, rounded at its free end, is made of ceramic or metallic material. The glow plug quickly reaches high temperatures and is less sensitive. In addition, the power consumption per ignition process is lower.

Vehicle heaters for which the burner according to the invention is intended are intended in particular for installation in passenger cars, trucks, ships, mobile homes, caravan trailers, bulldozers and the like. When installing the vehicle heaters in motor vehicles with internal combustion engines, the heater can be integrated into the liquid circuit, which is usually provided for cooling the internal combustion engine and heating the interior of the vehicle. In general, the vehicle heater can either be a so-called water heater, which emits the generated heat to a liquid circuit, or a so-called air heater, which emits the generated heat directly as a warm air flow. Petrol or diesel are primarily considered as fuels.

The burner according to the invention can also be used as a heat generator for the thermal regeneration of particle filters, in particular in the exhaust line of diesel engines. The invention and refinements of the invention are explained in more detail below with reference to an exemplary embodiment shown in the drawing. It shows:

Fig. 1 in a vertical longitudinal section along I-I in Fig. 2 the

Burner area of a vehicle heater; Fig. 2 in cross section along II-II in Fig. 1 that area of the burner where the glow plug is positioned.

1 shows the burner area of a vehicle heating device which, as the most important components, has a combustion chamber 2 with a glow plug 4 and with a fuel supply device 6 to be described later, and a combustion air blower 8. The housing of the heater is not shown for reasons of clarity. In addition, the heater in Fig. 1 includes the right

Combustion chamber 2 then a heat exchanger for transferring heat from the hot combustion gases to a liquid or air.

The combustion air blower consists of an electric motor 10 and an impeller 12, which is shown schematically in FIG. 1. In practice, side channel blowers are often used, which have a fixed channel and a rotating impeller rotating at a short distance from it.

The combustion chamber essentially consists of an end region 14 on the left in FIG. 1 and a main combustion region 16 adjoining on the right in FIG. 1. This is followed by a flame tube 18 to the right in FIG. 1, in which the combustion of the fuel ends . The end region 14 of the combustion chamber 2 has a cylindrical one

Combustion chamber wall 20 and on the left in FIG. 1 a final combustion chamber floor 22 which, apart from a bulge to be described later, is essentially in the form of a circular disk. At the transition from the combustion chamber wall 20 to the combustion chamber floor 22, a connection piece 24 with an internal thread is provided at one point. The main combustion region 16 of the combustion chamber 2 is cylindrical and coaxial with the end region 14 described. The main combustion region 16 has a larger diameter than the end region 14. The wall of the main combustion region 16 has several circumferential rows of openings 26 axially one behind the other, through which the combustion air comes in from the outside flows into the main combustion area 16. On the right in FIG. 1, the main combustion region 16 is closed off by a transverse flame diaphragm 28 which has a large passage opening 30 for the outflowing hot gas in the center. The combustion chamber arrangement is on a transverse wall by means of a funnel-shaped or a cylindrical component 32

34 of the heater attached.

A cylindrical combustion chamber wall lining part 36 made of ceramic material is attached to the inside of the cylindrical combustion chamber wall 20 of the end region 14 of the combustion chamber 2.

Provided on the inside on the combustion chamber base 22 is a combustion chamber base lining part 38 which, apart from a material omission to be described further below, is in the form of a circular disk. The left end face in FIG. 1 of the combustion chamber wall lining part 36 bears against the combustion chamber floor lining part 38. Multiple radial

Openings 40 are provided in the combustion chamber wall 20 and the combustion chamber wall lining part 36 so that combustion air can flow in. The combustion chamber floor lining part 38 consists of spun metal in the exemplary embodiment described.

2 that the glow plug 4 is positioned with its longitudinal axis in the tangential direction relative to the combustion chamber wall 20. Alternatively, the glow plug 4 could be arranged radially or be inclined at any angle between tangential and radial arrangement. In the designated embodiment, the longitudinal axis of the glow plug 4 is perpendicular. Alternatively, the glow plug 4 could be arranged at another point on the combustion chamber wall 20, which can be illustrated by rotating the glow plug 4 about the longitudinal central axis of the combustion chamber 2. With regard to "further outside" (ie to the left in Fig. 2) and "further inside" (to the right in Fig. 2), the glow plug 4 in the illustrated embodiment is arranged so that it sits exactly in front of the end face 42 of the combustion chamber wall lining part 36 . Alternatively, the glow plug 4 could be moved further to the right in FIG. 2, so that a small one

Part of its glow region 44 projects inward beyond the inner circumference of the combustion chamber wall lining part 36. According to a further alternative, the glow plug 4 could also be arranged a little further than shown to the left in FIG. 2, so that a certain distance between the inner circumference of the combustion chamber wall

Lining part 36 and the glow area 44 of the glow plug 4.

As far as the positioning of the glow plug 4 can be seen in FIG. 1 with regard to the axial direction of the combustion chamber 2, the glow region 44 has a small axial distance from the end face 42 of the

Combustion chamber wall lining part 36 and a small distance from a bulge 46 of the combustion chamber base 22.

The glow plug 4 is screwed into the socket 24. The glow plug 4 is connected to a control unit (not shown) via two current conductors, not shown, from where it receives power when ignition in the heater is required.

The bulge 46 of the combustion chamber base 22 already mentioned above is designed such that the glow plug 4 can be accommodated in its intended position with respect to the right / left in FIG. 2 and with regard to the axial direction of the combustion chamber 2.

The combustion chamber floor lining part 38 differs from the complete circular disk shape in that the material on the left and above is omitted from the boundary line 48 shown in FIG. 2, which runs like the legs of a right angle. A recess space 50 is thus formed which, overall, very roughly speaking, is cylindrical with vertical axes and is of sufficient size to accommodate the glow area 44 of the glow plug 4. The recess space 50 is axial bounded at the rear (left in FIG. 1) and on the outside (left in FIG. 2) by the bulge of the combustion chamber base 2; axially at the front (on the right in FIG. 1), the recess space 50 is delimited by the end face 42 of the combustion chamber wall lining part 36; On the inside (on the right in FIG. 2) and below, the recess space 50 is delimited by the boundary line 48 described further above.

Since the vertical part of the boundary line 48 lies further inward to the longitudinal axis of the combustion chamber 2 than the region there of the inner circumference of the combustion chamber wall lining part 36, one in FIG

Axial direction, substantially circular section-shaped transition opening 52 is formed between the recess space 50 and the interior of the end region 14 of the combustion chamber 2.

It should be noted that the glow plug 4 is alternatively a

Can be positioned a little further to the right in FIG. 1, the end face 42 of the combustion chamber wall lining part 36 should have been somewhat withdrawn in this area. In this case, the recess space 50 would not only be due to the material omission of the combustion chamber floor lining part 38 but also also

Omission of material formed on the combustor wall liner 36.

1 also shows an essentially cylindrical attachment 6 on the back of the combustion chamber base 22. This attachment

6 is laterally offset from the bulge 46, as can be seen in Fig. 2, where the attachment 6 is located, although it is in front of the

Plane of the drawing. In the place of the essay 6

Combustion chamber floor 22 has an opening which cannot be seen in the drawing. The attachment 6 is filled with metal web, which adjoins the metal web of the combustion chamber bottom lining part 38. A fuel line 54 opens into the interior of the attachment 6. A fuel pump (not shown) and the line 54 can thus do this

Metal web of the combustion chamber bottom lining part 38 fuel is supplied from where the fuel into the interior of the end region

14 into the combustion chamber 2, but also into the recess space 50 inside, evaporated. One can, but need not, choose a porous material for the combustion chamber wall lining part 36, for example porous ceramic or woven metal. In this case, fuel also enters the combustion chamber wall lining part 36 by capillary action, from where it enters the interior of the

End region 14 of the combustion chamber 2 evaporates.

In the bulge 46, a generally axially extending bore of relatively small diameter is provided, through which the combustion air required to ignite the glow area 44 of the glow plug 4 into the

Recess 50 can flow.

Arrows in Fig. 1 indicate how the. Combustion air required by the fan 8 through the openings 40 in the end region 14 and through the openings 26 in the main combustion region 16 of the

Combustion chamber flows and, like a small amount of combustion air, flows through the bore 56 described in the last paragraph into the recess space 50.

In Fig. 2 it can be seen that the transition opening 52 has a size that only makes up a small percentage of the area of the combustion chamber bottom 22 or the combustion chamber bottom lining part 38.

Claims

claims

1. Burner of a vehicle heater, which has:

(a) a fan (8) for supplying combustion air;

(b) a combustion chamber (2) which has a lining (36, 38) on part of its inner surface which is at least partially porous;

(c) means (6,54) for supplying fuel to the porous region of the liner (36,38);

(d) and an electric glow plug (4) for igniting the fuel evaporated from the lining, characterized in that

(e) that the end region (14) of the combustion chamber (2) opposite the hot gas outlet is formed with an essentially cylindrical wall (20) and a combustion chamber base (22); (f) that the lining (38) is provided for the combustion chamber base (22) and at least a part of the length of the combustion chamber wall (20) adjoining it; (g) that the glow area (44) of the glow plug (4) is arranged in a recess space (50) of the lining (36, 38), the recess space (50) via an open transition (52) to the interior of the combustion chamber (2) communicates.

2. Burner according to claim 1, characterized in that the glow plug (4) is arranged substantially in the tangential direction relative to the combustion chamber wall (20).

3. Burner according to claim 1 or 2, characterized in that the lining is a combustion chamber bottom lining part

(38) and an essentially cylindrical combustion chamber wall lining part (36) adjoining it with an end face having; and that the recess space (50) is essentially formed by local material omission on the combustion chamber bottom lining part (38) in comparison to a disk-like shape.

4. Burner according to one of claims 1 to 3, characterized in that the lining comprises a combustion chamber bottom lining part (38) and an essentially cylindrical combustion chamber wall lining part (36) adjoining it with an end face; and that the open transition (52) is essentially formed by local material omission on the combustion chamber bottom lining part (38) in comparison to a disk-like shape.

5. Burner according to one of claims 1 to 4, characterized in that the open transition (52) - seen in the axial direction of the combustion chamber end region - is substantially circular.

6. Burner according to one of claims 1 to 5, characterized in that the glow plug (4) is a glow plug.

7. Burner according to one of claims 1 to 6, characterized in that the lining has a combustion chamber bottom lining part (38) made of woven metal.

8. Burner according to one of claims 1 to 7, characterized in that the lining has a combustion chamber wall lining part (36) made of ceramic.