BURNER ASSEMBLY FOR A MOBILE HEATING DEVICE AND INSERT COMPONENT WITH RETAINING RING FOR AN EVAPORATOR

Abstract

Burner assembly (1) for a mobile fuel-operated heating device, in particular for a vehicle, comprises an evaporator (20) which is configured to evaporate a fuel supplied to it, an evaporator receptacle (24) which is configured to receive the evaporator (20), a circumferential wall (16) which defines a combustion chamber (14) in which a gas mixture containing the evaporated fuel may be combusted, wherein the circumferential wall (16) defines a central axis (M), a glow plug (10) with a shaft section (12) comprising a glow element, which is configured to convert a current flowing through it, when a voltage is applied, into heat for igniting the gas mixture, and a first opening (15) which is formed in the circumferential wall (16) of the combustion chamber (14) and through which the shaft section (12) of the glow plug (10) extends substantially radially into the combustion chamber (14). A holder arrangement (44, 45, 46, 17, 8) for the glow plug (10) is configured to allow a pivotability of the shaft section (12) of the glow plug (10) within the combustion chamber (14) in a direction (R) along the central axis (M) away from the evaporator (20). A corresponding insert component with an integrally formed retaining ring for the evaporator is also provided.

Claims

1. A burner assembly for a mobile fuel-operated heating device for a vehicle, comprising: an evaporator which is configured to evaporate a fuel supplied to the evaporator; an evaporator receptacle which is configured to receive the evaporator; a circumferential wall which defines a combustion chamber in which a gas mixture containing the evaporated fuel may be combusted, wherein the circumferential wall defines a central axis (M); a glow plug with a shaft section comprising a glow element, which is configured to convert a current flowing through it, when a voltage is applied, into heat for igniting the gas mixture; a first opening which is formed in the circumferential wall of the combustion chamber and through which the shaft section of the glow plug extends substantially radially into the combustion chamber; characterized by a holder arrangement for the glow plug, which holder arrangement is configured to allow a pivotability of the shaft section of the glow plug within the combustion chamber in a direction (R) along the central axis (M) away from the evaporator.

2. The burner assembly according to claim 1, wherein the holder arrangement comprises a spring element which is operatively connected to the glow plug and is configured to apply a spring force (Fs) to the glow plug, which spring force (Fs) presses the shaft section, preferably in the direction R toward the evaporator.

3. The burner assembly according to claim 2, wherein the holder arrangement comprises a holder element which is fixedly positioned in relation to the evaporator receptacle and/or the circumferential wall, wherein the holder element comprises a second opening which lies opposite the first opening outside the combustion chamber in an at least partially overlapping manner, wherein the shaft section of the glow plug extends through the second opening.

4. The burner assembly according to claim 3, wherein a length of the second opening parallel to the central axis (M) is greater than a length of the first opening parallel to the central axis (M).

5. The burner assembly according to claim 3, wherein the shaft section of the glow plug has a cross-sectional profile, wherein the second opening has an opening area which is greater than the cross-sectional profile.

6. The burner assembly according to claim 3, wherein the first opening has a first contact surface and the second opening has a second contact surface, wherein the first contact surface and the second contact surface delimit the respective openings on the side facing away from the evaporator, wherein the spring element is configured to exert the spring force (Fs) on the shaft section of the glow plug and thereby to press the latter against or towards both contact surfaces.

7. The burner assembly according to claim 6, wherein a position of the second contact surface projected onto the central axis (M) further from the evaporator corresponds to a position of the first contact surface projected onto the central axis (M).

8. The burner assembly according to claim 3, wherein the holder element is configured integrally with a retaining ring which is configured to hold and to press the evaporator in the evaporator receptacle.

9. The burner assembly according to claim 8, wherein the retaining ring furthermore has an all-round flange portion which is received between a burner flange that is formed integrally with the circumferential wall and an evaporator receptacle flange and is preferably welded thereto.

10. The burner assembly according to claim 8, wherein the retaining ring furthermore has a cylindrical section and a holding section which adjoins the cylindrical section and has an inner opening, the cylindrical section and the holding section together form a pot shape, which receives the evaporator receptacle positioned oppositely, and presses said evaporator.

11. The burner assembly according to claim 10, wherein the inner opening is closed by a grid through which the evaporated fuel can pass.

12. A fuel-operated mobile heating device for a vehicle, comprising a burner assembly according to claim 1.

13. An insert component for a burner assembly for a mobile fuel-operated heating device, comprising: a retaining ring for an evaporator with a holding section for pressing the evaporator in an evaporator receptacle of the burner assembly, with an inner opening for releasing a fuel evaporated by the evaporator into a combustion chamber of the burner assembly, and with a flange section for fastening the retaining ring to a burner flange that is formed integrally with a circumferential wall of the combustion chamber and to an evaporator receptacle flange; and a holder element for holding a glow plug outside and for defining an orientation of a shaft section of the glow plug within the combustion chamber.

14. The insert component according to claim 13, wherein the retaining ring furthermore has a cylindrical section which extends in an axial direction between the holding section and the flange section.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0041] The invention is explained below by way of example with reference to the following figures.

[0042] In the figures:

[0043] FIG. 1 shows a sectional view through a burner assembly according to a first example according to prior art with an axial arrangement of the glow plug;

[0044] FIG. 2 shows a sectional view through a burner assembly according to a second example according to prior art with a radial arrangement of the glow plug;

[0045] FIG. 3 shows a sectional view through a burner assembly according to an embodiment with a radial arrangement of the glow plug;

[0046] FIG. 4A shows a perspective illustration of the spring element from FIG. 3;

[0047] FIG. 4B shows an enlarged illustration of the elements of the holder arrangement from FIG. 3, without a glow plug;

[0048] FIG. 5 shows another enlarged illustration of the elements of the holder arrangement from FIG. 3, with a glow plug;

[0049] FIG. 6 shows a schematic illustration of the mutually opposite openings of the holder arrangement with possible resulting pivot positions of the glow plug;

[0050] FIG. 7 as FIG. 3, but in a perspective sectional illustration; and

[0051] FIG. 8 shows an insert component with a retaining ring and with an integrally formed holder element according to an embodiment.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

[0052] In the following description of the drawings, identical reference symbols designate identical or comparable components.

[0053] The features of the invention disclosed in the above description, in the drawings and in the claims may be essential for the implementation of the invention both individually and in any desired combination.

[0054] FIG. 3 shows a sectional view through a burner assembly 1 according to an embodiment with a radial arrangement of the glow plug 10. The burner assembly 1 comprises a combustion chamber 14 which is fixed by a cylindrical circumferential wall 16, an evaporator receptacle 24, an evaporator 20 received therein and a retaining ring 40 with a holder element 44 formed integrally with the retaining ring 40. The combustion chamber 14 or the circumferential wall 16 defines a central axis M. Comparatively small, radially directed air introduction holes 18 as well as further air introduction holes 18 generating a swirl, so-called flaps, are formed in the circumferential wall 16. The combustion chamber 14 tapers in the downstream direction (downward in FIG. 3). The evaporator receptacle 24 has an enclosure 25 with a pot-shaped receptacle for the evaporator 20. The evaporator 20 is pressed into this receptacle. Without limiting the generality of the aspects described herein, the evaporator 20 may be basalt wool. An evaporator dome, in which a further evaporator (without reference symbols) with a different porosity may be introduced, is formed in the evaporator receptacle 24 above the evaporator 20. During operation, a fuel such as gasoline, diesel, ethanol, etc., may be supplied to the evaporator 20 via the evaporator dome via a fuel supply line 22.

[0055] The evaporator receptacle 24 forms, as a component, an end-face termination for the burner assembly 1. However, the combustion chamber 14 is delimited on the end face by the retaining ring 40 and a grid 50 (cf. FIG. 8) arranged therein above or within an inner opening 48, such that the evaporator receptacle 24 (advantageously) is no longer in direct contact with the combustion chamber 14. The retaining ring 40, together with the grid 50, has the task of maintaining the compression of the evaporator 20 in the evaporator receptacle 24. During operation, the supplied fuel is evaporated in the evaporator 20, and passes via the grid 50 into the combustion chamber 14, where it is mixed with the fuel flowing through the air introduction holes and is combusted, after initial ignition via the glow plug 10.

[0056] The glow plug 10 has a form known per se in this technical field. The glow plug 10 comprises a head 11 which, inter alia, comprises connection electronics. The glow plug 10 is supplied with electrical power via electrical connection lines 9. Furthermore, the glow plug 10 has a shaft section 12 which extends into the combustion chamber 14 in a substantially radial direction through a first opening 15 (cf. FIGS. 4B and 5) in the circumferential wall 16. The first opening 15 is designed as a mere recess in the combustion chamber wall without inner or outer structures. In particular, it is not designed as a plug or screw bush. A cross-sectional profile of the first opening 15 substantially corresponds to a cross-sectional profile of the shaft section 12 of the glow plug 10. The first opening 15 may be designed to be slightly larger than the cross-sectional profile of the shaft section 12 by the extent of a manufacturing tolerance and due to production-related roundings in the corners (cf. FIG. 8).

[0057] With reference to FIGS. 4A and 4B and 5, the holder arrangement 4 is described in greater detail. The holder arrangement 4 comprises a tab or holder element 44 for the glow plug 10, which tab or holder element integrally adjoins a flange section 41 of the retaining ring 40. The flange section 41 extends in a plane perpendicular to the central axis M of the combustion chamber 14 and parallel to a plane of extent of the evaporator 20 and parallel to a holding section 49 forming the opening 48 of the retaining ring 40 with the grid 50 arranged thereon. With the aid of a flat cylindrical section 47 of the retaining ring 40, the retaining ring 40 forms, basically like the evaporator receptacle 24, a flat pot shape which in turn receives a corresponding pot shape of the enclosure 25 of the evaporator receptacle 24 for receiving the evaporator 20 therein. Consequently, the retaining ring 40 has a relatively flat design.

[0058] As indicated by the dotted line in FIG. 4B, the flange section 41 forms, jointly with a combustion chamber flange 17 and an evaporator receptacle flange 26, a flange package 6 (cf. FIGS. 3 and 7), the flange section 41 being enclosed by combustion chamber flange 17 and the evaporator receptacle flange 26 in a sandwiched manner. The dotted line indicates a weld seam in a schematic manner. The flange section 41 extends all-round in the retaining ring, so that an all-round closed connection with the combustion chamber flange 17 and the evaporator receptacle flange 26 is achieved.

[0059] Since the flange section 41 is exposed with its outer edge to an external environment, the tab-like holder element 44 may extend in an integrally configured manner from the flange section 41 into an external environment of the combustion chamber 14. As can be seen in the figures, the tab-like holder element 44 is bent by 90 in the downstream direction at a slight distance from the circumferential wall 16, in order to then extend parallel to the central axis M to the central axis M and to the circumferential wall 16.

[0060] The overall retaining ring 40 with the holding arrangement 4 and the holder element 44 is formed in the embodiment by a deep-drawn and bent, flat insert component. As can be seen in FIG. 4B, the wall thickness of the insert component (for example 0.8 mm) approximately corresponds to that of the circumferential wall 16 (for example 1 mm) of the combustion chamber 14. This also facilitates the welding of the abovementioned flange sections. A second opening 45 is formed in the tab-like holder element 44. As can be seen in FIG. 3 and FIG. 5, the shaft section 12 extends both through the first opening 15 and through the second opening 45. For the optional case in which the glow plug 10 comprises a metal or ceramic sleeve, it may be in direct contact with the openings 15, 45 as part of the shaft section 12 of the glow plug 10.

[0061] As can be seen in FIG. 5, a spring element 8, which can also be seen in FIG. 4A, is configured between the shaft section 12 and the combustion chamber 14. The spring element 8 is embodied here as a split pin which is compressed between the shaft section 12 and the combustion chamber 14. In other words, the spring element 8 exerts, supported on the combustion chamber flange 17, a tensioning force directed downward in FIG. 5 onto the shaft section 12, i.e. in the downstream direction or parallel to the central axis M and to the planes of the opening areas each of the first opening 15 and the second opening 45, anddepending on the current pivot position of the glow plugsubstantially or approximately perpendicularly to the direction in which the glow plug 10 extends. As a result of this tension force, the shaft section 12 is pressed against corresponding contact surfaces 151, 451 of the first and second openings 15, 45.

[0062] As can be seen in FIG. 6, the first opening 15 has a smaller length in a direction parallel to the central axis M than the second opening 45. The length of the first opening 15 in the direction parallel to the central axis M approximately corresponds to the diameter of the shaft section 12, while the length of the second opening 45 in the direction parallel to the central axis M is greater than the diameter of the shaft section 12. As a result, the shaft section 12 can move in the second opening 45 in the direction parallel to the central axis M, which is not the case with respect to the first opening 45. This results in a possible rotational movement of the glow plug 10, such that the shaft section 12 can basically move toward or away from the evaporator 20, as indicated by the double arrow in FIG. 3, which indicates the corresponding rotational direction R, which is substantially parallel to the central axis M for small pivot ranges.

[0063] According to a specific non-limiting embodiment, as a result of the mutual arrangement and size of the openings 15, 45, the shaft section 12 may ideally be inclined toward the evaporator by 2 with respect to an exact radial direction perpendicular to the central axis in an initial state, in which the shaft section contacts the two contact surfaces 151 and 451, and may be inclined away from the evaporator by 8 with respect to an exact radial direction perpendicular to the central axis in a state, in which the shaft section 12 releases from the contact surface 451 and contacts an opposite contact surface 452 (maximum pivot range). The allowed pivot range is thus 10 in this case. The range is so small that it is scarcely visibly reflected by differences in length of the openings in FIGS. 3, 4B, 5 and 7, for which reason the difference is illustrated exaggerated in FIG. 6 in order to illustrate the effect.

[0064] The spring element 8 is embodied as a split pin as described. It can be seen in FIG. 4A that this split pin comprises a bulbous base section 81, a pressure section 82, a contact section 83 and an end section 84. The contact section 83 lies flat against the combustion chamber flange 17 in the installed state. In this state, the bulbous base section 81 or the end section 84 lies against a holding flange 46 which is bent once again by 90 toward the circumferential wall 16 by the tab-like holder element 44, in order to hold the spring element 8 in position. The end section 84 bulges like the base section 81 in the downstream direction in the installed state, i.e. downward in FIG. 4B, while the intermediate pressure section 82 biases the shaft section 12. In order to secure the radial position of the shaft section 12, the latter has a groove (not shown) into which the pressure section 82 may engage. A cooling lug 88 may be interposed between the pressure section 82 and the surface of the groove.

[0065] Returning to FIG. 6, in particular the pressure section 82 of the spring element 8 presses the shaft section 12 against the contact surfaces 151 and 451, such that the glow plug 10 assumes a predetermined position relative to the combustion chamber 14 and to the evaporator 20 despite its basic movability. Due to deposits during operation over the service life, the evaporator 20 may deform, and thereby come into contact, for example, with a distal region of the shaft section 12. As a result, a force Fd1 is exerted on the shaft section 12. The first opening 15 in this case forms a pivot point for the glow plug 10. Correspondingly, the force Fd1 exerted on the shaft section 12 is transformed into a lever force Fd2, with which the pressure section 82 of the spring element 8 is forced back against its own tension force Fs, which is designed to be significantly less. Nevertheless, this tension force Fs holds the glow plug 10 in position, wherein the distal region of the shaft section 12 is in contact with the continuously further deforming evaporator. This process continues over the service life. At the same time, the shaft section 12 is protected from damage.

[0066] FIG. 7 once again shows an overview of the burner assembly 1 as in FIG. 3, but in a perspective sectional view.

[0067] FIG. 8 shows an embodiment of an insert component 400 with an integrally formed retaining ring 40 and holder element 44 for the glow plug 10 and with a grid 50. The embodiment shown in FIG. 8 may be identical to the retaining ring 40 shown in FIGS. 3 to 7, so that the detailed description can be dispensed with.

[0068] However, it should be noted that, according to another aspect, the embodiment of an insert component 400 as shown in FIG. 8 can be modified in such a manner that the second opening 45 may certainly also be formed only with a cross-sectional area corresponding to the shaft section 12. In this case, the glow plug cannot be guided or moved laterally within the second opening 45. In other words, in this case, the spatial position of the glow plug 10 is substantially fixed and rigid. The spring element 8 shown in FIGS. 3, 4A, and 5-7 may therefore serve merely for fixing/securing the glow plug 10 in the holder arrangement 4 in the radial direction in this embodiment.

[0069] The modified embodiment may indeed not take account of the deformation of the evaporator 20 over the service life in interaction with the features of the burner assembly 1 shown in FIGS. 3, 4A, and 5-7 without movability of the glow plug. However, a simple and cost-effective insert component may advantageously still be realized which allows, on the one hand, a flat design of the evaporator receptacle 24 and thus a shortening of the overall length of the evaporator burner and, on the other hand, allows an axial assembly of the components for the evaporator. A complex production of plug or screw bushes may be dispensed with.

LIST OF REFERENCE NUMERALS

[0070] 1 burner assembly [0071] 4 holder arrangement (comprises the references 44, 45, 46, 17, 8) [0072] 6 welded flange package [0073] 8 spring element [0074] 9 electrical connection lines [0075] 10 glow plug [0076] 11 head [0077] 12 shaft section [0078] 14 combustion chamber [0079] 15 first opening [0080] 151 contact surface [0081] 16 circumferential wall (combustion chamber) [0082] 17 combustion chamber flange [0083] 18 air introductions holes [0084] 20 evaporator [0085] 22 fuel supply line [0086] 24 evaporator receptacle [0087] 25 enclosure (for evaporator in evaporator receptacle) [0088] 26 evaporator receptacle flange [0089] 30 holding element (conventional) [0090] 40 retaining ring (invention) [0091] 41 flange section [0092] 44 holding element [0093] 45 second opening [0094] 451 contact surface [0095] 46 holding flange (on holder arrangement for supporting the spring element) [0096] 47 cylindrical section [0097] 48 opening [0098] 49 holding section [0099] 400 insert component [0100] 50 grid [0101] 81 base section [0102] 82 pressure section [0103] 83 contact section [0104] 84 end section [0105] 90 bushing, plug socket [0106] 100 Evaporator burner (prior art): axial bushing for glow plug [0107] 200 Evaporator burner (prior art): radial bushing for glow plug [0108] M Central axis [0109] R (Pivoting) direction of the glow plug