Heating unit housing for a fuel-operated vehicle heater

Abstract

Heating appliance housing (12) for a fuel-operated heating appliance, comprising a housing body (26) elongated in the direction of a housing longitudinal axis (G), with a housing circumferential wall (22) radially outwardly delimiting an airflow space (24) through which air can flow substantially in a main flow direction (HD) in the direction of the housing longitudinal axis (G), with an air inlet area (36) at a first axial end area and an air outlet area (54) at a second axial end area (35), wherein the housing body (26) has a first housing body section (28) providing the air inlet area (36) and a second housing body section (30) connected or to be connected to the first housing body section (28) and providing the air outlet area (54),wherein the first housing body section (28) provides a first part (42) of the housing circumferential wall (22) and the second housing body section (30) provides a second part (44) of the housing circumferential wall (22) adjoining the first part (42) of the housing circumferential wall (22), characterized in that the second housing body section (30), which is made in one piece of plastic material, has a housing end wall (46) adjoining the second part (44) of the housing circumferential wall (22), tapering in the direction of the longitudinal axis (G) of the housing in the main flow direction (HD), wherein an outlet nozzle (48) extending in the direction of a nozzle longitudinal axis (S) adjoins the housing end wall (46), providing an outlet opening (52) of the air outlet area (54) in a first nozzle end region (50),wherein the outlet nozzle (48) connects to the housing end wall (46) in a second nozzle end region (56) located away from the outlet opening (52) with a dome-shaped end wall region (58) that closes off the outlet nozzle (48) in the direction of the nozzle longitudinal axis (S), wherein the second housing body section (30) is shaped such that a main outflow direction (HA) in the area of ​​the air outlet region (54) is not parallel to the main flow direction (HD), and wherein in a circumferential region of the second housing body section (30) covered by the outlet nozzle (48) the housing end wall (46) extends into the interior (60) of the outlet nozzle (48).

Description

The present invention relates to a heater housing for a fuel-operated vehicle heater according to the preamble of claim 1. From DE 197 34 814 C1, a vehicle heater with a heater housing is known. The heater housing is constructed with a housing body elongated in the direction of a longitudinal axis, which provides a circumferential wall enclosing a flow chamber for the air to be heated. A first housing body section, constructed with two housing parts of approximately equal length, provides a first part of the housing circumferential wall of the heater housing and an air inlet area. A second housing body section, significantly shorter in the direction of the housing circumferential axis, provides a second part of the housing circumferential wall and, concentric to the housing longitudinal axis, an air outlet area.The air outlet area is provided with an outlet opening formed in an outlet nozzle extending in the direction of the longitudinal axis of the housing, so that a main outflow direction of air leaving the heater housing essentially corresponds to a main flow direction with which the air inside the heater housing is guided along a heat exchanger contained therein. From DE 10 2004 010 385 A1, a heating appliance housing for a fuel-operated heating appliance according to the preamble of claim 1 is known. In this known heating appliance housing, the second housing body section is constructed with two parts that are rotatably mounted relative to each other. By rotating these two parts relative to each other, an air outlet area formed on one of these parts can be positioned such that a main outflow direction located therein is either parallel to a main flow direction in the first housing body section or is angled to it at an angle that is adjustable up to a maximum angle. The object of the present invention is to provide a heater housing for a fuel-operated vehicle heater, which, with a compact design, achieves improved airflow for the air flowing through such a heater housing. According to the invention, this problem is solved by a heater housing for a fuel-operated vehicle heater according to claim 1.The heating device housing according to the invention comprises a housing body elongated in the direction of a housing longitudinal axis, which, with a housing circumferential wall, defines an airflow space radially outwards, through which air can flow substantially in a main flow direction in the direction of the housing longitudinal axis, and has an air inlet area at a first axial end area and an air outlet area at a second axial end area, wherein the housing body has a first housing body section providing the air inlet area and a second housing body section connected or to be connected to the first housing body section and providing the air outlet area, wherein the first housing body section provides a first part of the housing circumferential wall and the second housing body section provides a second part of the housing circumferential wall adjoining the first part of the housing circumferential wall.The second housing body section is shaped in such a way that a main outflow direction in the area of ​​the air outlet is not parallel to the main flow direction. In the heater housing constructed according to the invention, the airflow is deflected within the housing itself in such a way that the main outflow direction does not correspond to the main flow direction, allowing the heated air to exit the heater housing laterally. This results in a compact design, particularly along the longitudinal axis of the housing, and enables installation in a vehicle with limited space along that axis. Since the airflow is deflected within the heater housing, this deflection can be achieved without significant pressure losses. In a particularly preferred embodiment, the main outflow direction can be essentially orthogonal to the main flow direction. To generate the flow deflection in the second housing body section, it is provided that the second housing body section has a housing end wall that tapers in the direction of the housing longitudinal axis in the main flow direction following the second part of the housing circumferential wall, and that an outlet nozzle extending in the direction of a nozzle longitudinal axis is connected to the housing end wall, providing an outlet opening of the air outlet area in a first nozzle end region, wherein the outlet nozzle connects to the housing end wall in a second nozzle end region away from the outlet opening with a dome-shaped end wall region that closes off the outlet nozzle in the direction of the nozzle longitudinal axis.Connecting the outlet nozzle to the tapered housing end wall with a dome-shaped end wall area causes the air, which is directed radially inwards along the tapered housing end wall, to be deflected on the inside of the dome-shaped end wall area and directed into the outlet nozzle. Zum Erreichen einer Strömungsumlenkung um etwa 90° kann die Stutzenlängsachse zur Gehäuselängsachse im Wesentlichen orthogonal sein oder / und diese schneiden. According to the invention, for a defined flow path into the outlet nozzle, the housing end wall extends into the interior of the outlet nozzle in a circumferential area of ​​the second housing body section covered by the outlet nozzle. For this purpose, for example, a flow opening leading to the interior of the outlet nozzle, preferably concentric to the longitudinal axis of the housing, can be provided in the housing end wall. To achieve increased variability in the discharge of air from the heating appliance housing, at least one branch nozzle section designed to provide an outlet opening of the discharge area can be provided at the outlet nozzle. In order to facilitate the least possible resistance-free drainage of the air directed radially inwards at the housing end wall into the outlet nozzle, a center of curvature of the end wall area can be arranged transversely to the longitudinal axis of the housing essentially in a central area of ​​the second housing body section. In particular, when the housing end wall is designed with a wall section extending partially inside the outlet nozzle and defining a flow opening, the center of curvature can be arranged transversely to the longitudinal axis of the housing in the area of ​​the center of the flow opening. For a variable design, the second housing body section can be connected to the first housing body section in a plurality of mounting positions rotated relative to each other about the longitudinal axis of the housing. For this purpose, for example, the first part of the housing circumferential wall and the second part of the housing circumferential wall can have an essentially square outer circumferential contour with respect to the longitudinal axis of the housing, so that the second housing body section can be connected to the first housing body section in four mounting positions rotated 90° relative to each other about the longitudinal axis of the housing. The second housing section is constructed from a single piece of plastic material to maintain a simple design. The invention further relates to a vehicle heater comprising a heater housing constructed according to the invention, a burner area included in the heater housing and a heat exchanger included in the heater housing for transferring heat generated in the burner area to air flowing through the heater housing. For improved flow guidance in a compact design in the direction of the housing longitudinal axis, it is proposed that the heat exchanger comprises a plurality of heat transfer fins arranged circumferentially around the housing longitudinal axis, extending radially outwards and essentially in the main flow direction, and that the heat transfer fins with an axial end region extend into the second housing body section and have an end structure adapted to the tapered housing end wall, tapering in the direction of the housing longitudinal axis. The present invention is described below with reference to the accompanying figures. Figure 1 shows a partial longitudinal section of a vehicle heater constructed with a heater housing not according to the invention; Figure 2 shows a representation corresponding to Figure 1 of an embodiment of the heater housing according to the invention; Figure 3, in its four different representations, shows four different positions of a second housing body section relative to a first housing body section of a heater housing; Figure 4 shows a perspective view of an alternative embodiment of a heater housing. Fig. 1 shows a partial longitudinal section of a fuel-operated vehicle heater 10, which is used to heat the air to be introduced into a vehicle interior. The vehicle heater 10 comprises a heater housing 12, which is described in more detail below, and within the heater housing 12 a burner section 14, of which essentially only a flame tube 16 is shown, and a heat exchanger 18 with a plurality of heat transfer fins 20 extending in the direction of a longitudinal axis G of the housing and radially outwards with respect to this axis. The heater housing 12, with its circumferential wall 22, encloses an airflow chamber 24 through which the air to be heated flows essentially in the direction of the housing's longitudinal axis G in a main flow direction HD. It should be noted that, due to the structural conditions, local flow directions may exist within the airflow chamber 24 that deviate from the main flow direction HD. However, it can be assumed, essentially or on average, that the air flowing through the airflow chamber 24 flows in the main flow direction HD, which is parallel to the housing's longitudinal axis G, which can essentially be a central longitudinal axis. The heater housing 12, shown in various assembly states in external view in Fig. 3, is constructed with a housing body 26, which in turn is constructed with two housing body sections 28, 30 successively aligned along the longitudinal axis G of the housing. The first housing body section 28 of the housing body 26 can be constructed with a main housing part 32 and a housing cover 34, through which access to the interior of the heater housing 12 is possible. The second housing body section 30 is preferably formed in one piece and, like the first housing body section 28, is constructed, for example, of plastic material. In a first axial end region of the housing body 26, an air inlet region 36 is formed. This comprises, on a housing end wall 38 that tapers, for example, in the direction of the housing longitudinal axis G, an inlet nozzle 40 with an inlet opening formed therein, through which the air to be heated enters the airflow chamber 24. For this purpose, an air impeller can be arranged inside the heater housing 12, which can be driven by a motor associated with a combustion air blower to convey air into the airflow chamber 24. The first housing body section 28 provides a first part 42 of the housing circumferential wall 22. A second part 44 of the housing circumferential wall 22 is formed on the second housing body section 30. The two parts 42, 44 of the housing circumferential wall 22 have a substantially square outer circumferential contour, so that, as illustrated in Fig. 3, the second housing section 30 can be attached to the first housing body section 28 in four different mounting positions rotated 90° relative to each other about the longitudinal axis G of the housing and connected to it, for example, by screwing and / or snapping. The second housing body section 30, adjoining the second part 44 of the housing circumferential wall 22, has a housing end wall 46, which tapers in the direction of the housing longitudinal axis G and may, for example, have a substantially rounded pyramidal or convex contour. An outlet nozzle 48 is provided in a second axial end region 35 of the housing body 26 such that it connects to the housing end wall 46 and, in some areas, also to the second part 44 of the housing circumferential wall 22. The outlet nozzle 48 extends in the direction of a nozzle longitudinal axis S and provides an outlet opening 52 of an air outlet area 54 of the heater housing 12 in a first axial nozzle end region 50. The nozzle longitudinal axis S may, for example, substantially correspond to the center axis of the outlet opening 52. The outlet opening 52 can, for example, have a circular cross-sectional contour. In its second axial end region 56, the outlet nozzle 48 connects to the housing end wall 46 of the second housing body section 30 with a dome-shaped curved end wall region 58. The outlet nozzle is preferably positioned such that its longitudinal axis S intersects the longitudinal axis G of the housing and forms an angle of approximately 90° with it. This results in the right-angled positioning of the outlet nozzle 48 with respect to the housing circumferential wall 22, which is particularly evident in Fig. 3. The air flowing through the airflow chamber 24 along the heat transfer fins 20 in the main flow direction HD is directed radially inwards, at least in some circumferential regions, by the tapering end wall 46 of the housing body, which thus acts like a funnel, upon entering the second housing body section 30. The air leaving the airflow chamber 24 therefore enters the interior 60 of the outlet nozzle 48 and, with the assistance of the inner surface of the dome-shaped end wall region 58, is deflected by approximately 90° with respect to the main flow direction HD without significant pressure loss and directed towards the first axial end region 50 of the outlet nozzle 48.There, the air heated by contact with the heat exchanger 18 leaves the heater housing 12 in the area of ​​the outlet opening 52 with a main outflow direction HA, which is essentially directed in the direction of the longitudinal axis S of the nozzle and is thus essentially orthogonal to the main flow direction HD. It should also be noted that this main outflow direction HA is the flow direction that the air leaving the heater housing 12 exhibits essentially or on average, although local deviations from such a main outflow direction HA may, of course, exist across the cross-section of the outlet opening 52. In the non-inventive embodiment shown in Fig. 1, the housing end wall 46 is interrupted where the outlet nozzle 48 connects to it, so that an open volume for air passage exists in the entire area where the outlet nozzle 48 meets the housing end wall 46 or the second part 44 of the housing circumferential wall 22, thus providing a very large opening cross-section for air to pass from the airflow chamber 24 into the outlet nozzle 48. In the inventive embodiment shown in Fig. 2, the housing end wall 46 also extends into the interior 60 of the outlet nozzle 48 in the circumferential area covered by the outlet nozzle 48.In the central area of ​​the housing end wall 46, a flow opening 62, arranged essentially concentrically with respect to the longitudinal axis G of the housing, is formed. This opening has, for example, a circular cross-section, through which the air leaving the airflow chamber 24 is directed into the outlet nozzle 48 and to the outlet opening 52 of the same. Thus, the housing end wall 46, which is also present in the circumferential area covered by the outlet nozzle 48, can exert a defined influence on the flow direction. In all illustrated embodiments, the heat transfer fins 20 also contribute to such a defined flow direction. In their axial end region 64, which is incorporated in the second housing body section 30, the heat transfer fins have a tapered end structure adapted to the tapered shape of the housing end wall 46. Fig. 2 shows that the center of curvature K of the approximately spherically segmented end wall region 58 lies in the area of ​​the housing longitudinal axis G and thus in a central area of ​​the housing body 26 or the second housing body section 30. Particularly in the embodiment shown in Fig. 2, with the housing end wall 46 extending into the interior 60 of the outlet nozzle 48 and thus encompassing the flow opening 62 arranged essentially centrally to the housing longitudinal axis G, the center of curvature K can be positioned transversely to the housing longitudinal axis G essentially in the area of ​​a center Z or the center point of the flow opening 62. This design of the end wall section 58 ensures that, upon exiting the airflow chamber 24, the air directed radially inwards at the housing end wall 46 is guided into the outlet nozzle 48 without significant flow resistance. It should be noted in this context that such flow deflection can also be achieved if the end wall section 58 is not exactly spherical or curved, or if the curved end wall section 58 is provided, for example, by a plurality of mutually angled, but individually uncurved, surface segments. With the previously described construction of a heater housing 12, or of a fuel-operated vehicle heater 10 built therewith, with reference to Figures 1, 2 to 3, it is possible to achieve a deflection of the airflow within the heater housing 12 without a significant throttling effect and thus without a significant pressure loss. The air can essentially flow out of the heater housing 12 laterally. This makes it possible to install such a heater 10 in confined spaces, which, for example, do not permit the connection of further components carrying the heated air to the heater housing 10 in the direction of the longitudinal axis G of the housing.By being able to attach the lid-like second housing body section 30 to the first housing body section 28 in different positions rotated relative to each other about the longitudinal axis G of the housing, the air emitted from the heater housing 12 can be directed in different directions transverse to the longitudinal direction G of the housing, depending on the installation situation generally specified for the vehicle heater 10. Further increased variability in air delivery can be achieved with the design shown in Fig. 4. It can be seen that two branch nozzle sections 66, 68 are provided on the second housing body section 30 in the area of ​​the outlet nozzle 48, or can be integrally formed on the second housing body section 30. In the illustrated embodiment, each of the two branch nozzle sections 66, 68 is closed. If necessary, an outlet opening can be created in the area of ​​each branch nozzle section 66, 68 by removing material that closes these sections. The center axis M1 of the outlet opening to be created on branch nozzle section 66 can, for example, essentially correspond to the longitudinal axis S of the nozzle.parallel to it, and an opening center axis M2 of the outlet opening to be created on the branch nozzle section 68 can, for example, essentially correspond to or be parallel to the longitudinal axis G of the housing. It is therefore possible, alternatively or in addition to the outlet opening 52 of the outlet nozzle 48, to create one or two points at which air can leave the heater housing 12 and, for example, flow into further pipe-like or hose-like air ducts or directly into a vehicle interior. In the inventive design of a heating appliance housing, the shape of the outlet nozzle with its domed end wall area results in less turbulence in the air flowing into the outlet nozzle, and there is a reduced tendency for backflow of air into the airflow chamber. This leads to a lower pressure drop and improved airflow around the heat transfer fins of the heat exchanger. The design of the housing end wall, to which the outlet nozzle connects, makes it possible to influence the flow pattern during the transition from the airflow chamber to the interior of the outlet nozzle.This also has a particular influence on how the heat exchanger 18 is surrounded by airflow in the area of ​​the axial end region 64 of the heat transfer fins 20, in order to achieve increased efficiency in heating the air flowing through the heater housing through enhanced thermal interaction.

Claims

Heating appliance housing (12) for a fuel-operated heating appliance, comprising a housing body (26) elongated in the direction of a housing longitudinal axis (G), with a housing circumferential wall (22) radially outwardly delimiting an airflow space (24) through which air can flow substantially in a main flow direction (HD) in the direction of the housing longitudinal axis (G), with an air inlet area (36) at a first axial end area and an air outlet area (54) at a second axial end area (35), wherein the housing body (26) has a first housing body section (28) providing the air inlet area (36) and a second housing body section (30) connected or to be connected to the first housing body section (28) and providing the air outlet area (54),wherein the first housing body section (28) provides a first part (42) of the housing circumferential wall (22) and the second housing body section (30) provides a second part (44) of the housing circumferential wall (22) adjoining the first part (42) of the housing circumferential wall (22), characterized in that the second housing body section (30), which is made in one piece of plastic material, has a housing end wall (46) adjoining the second part (44) of the housing circumferential wall (22), tapering in the direction of the longitudinal axis (G) of the housing in the main flow direction (HD), wherein an outlet nozzle (48) extending in the direction of a nozzle longitudinal axis (S) adjoins the housing end wall (46), providing an outlet opening (52) of the air outlet area (54) in a first nozzle end region (50).wherein the outlet nozzle (48) connects to the housing end wall (46) in a second nozzle end region (56) located away from the outlet opening (52) with a dome-shaped end wall region (58) that closes off the outlet nozzle (48) in the direction of the nozzle longitudinal axis (S), wherein the second housing body section (30) is shaped such that a main outflow direction (HA) in the area of ​​the air outlet region (54) is not parallel to the main flow direction (HD), and wherein in a circumferential region of the second housing body section (30) covered by the outlet nozzle (48) the housing end wall (46) extends into the interior (60) of the outlet nozzle (48). Heating device housing (12) according to claim 1, characterized in that the main outflow direction (HA) is essentially orthogonal to the main flow direction (HD). Heating appliance housing (12) according to claim 1 or 2, characterized in that the nozzle longitudinal axis (S) is substantially orthogonal to the housing longitudinal axis (G) and / or intersects it. Heating appliance housing (12) according to one of claims 1-3, characterized in that a flow opening (62) to the interior (60) of the outlet nozzle (48) is provided in the housing end wall (46), preferably being substantially concentric to the longitudinal axis (G) of the housing. Heating appliance housing (12) according to one of claims 3-4, characterized in that at least one branch nozzle section (66, 68) designed to provide an outlet opening of an outlet area is provided on the outlet nozzle (48). Heating appliance housing (12) according to one of claims 3-5, characterized in that a center of curvature (K) of the end wall area (58) is arranged transversely to the longitudinal axis of the housing (G) essentially in a central area of ​​the second housing body section (30). Heating appliance housing (12) according to claim 4 and claim 6, characterized in that the center of curvature (K) is arranged transversely to the longitudinal axis (G) of the housing in the region of a center (Z) of the flow opening (62). Heating appliance housing (12) according to one of claims 1-7, characterized in that the second housing body section (30) can be connected to the first housing body section (28) in a plurality of mounting positions rotated relative to each other about the longitudinal axis (G) of the housing. Heating appliance housing (12) according to claim 8, characterized in that the first part (42) of the housing circumferential wall (22) and the second part (44) of the housing circumferential wall (22) have a substantially square outer circumferential contour with respect to the longitudinal axis (G) of the housing, and that the second housing body section (30) can be connected to the first housing body section (28) in four mounting positions rotated 90° relative to each other about the longitudinal axis (G) of the housing. Vehicle heater (10) comprising a heater housing (12) according to one of the preceding claims, a burner area (14) included in the heater housing (12) and a heat exchanger (18) included in the heater housing (12) for transferring heat generated in the burner area (14) to air flowing through the heater housing (12). Vehicle heater (10) according to claim 10, characterized in that the heat exchanger (18) comprises a plurality of heat transfer fins (20) arranged circumferentially around the longitudinal axis (G) of the housing, extending radially outwards and substantially in the main flow direction (HD), and that the heat transfer fins (20) extend into the second housing body section (30) with an axial end region (64) and have an end structure adapted to the tapered housing end wall (46) and tapering in the direction of the longitudinal axis (G) of the housing.

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