Air heater for mobile applications with axially mountable housing shells

Abstract

An air heater (2, 102), in particular a fuel-based air heater, for a vehicle comprises an assembly (11) for generating heat; a heat exchanger element (13) thermally interacting with the assembly (11), an outer housing (G) that accommodates the assembly (11) and the heat exchanger element (13), wherein the outer housing (G) and the heat exchanger (30) form a hot air duct (39) between them, a hot air blower (3) that is configured to draw in hot air (H) via a hot air inlet (14) of the outer housing (G), convey it along a flow direction (RH) through the hot air duct (39) and discharge it via a hot air outlet (22) of the outer housing (G), and a combustion air blower module (6, 106) that includes a combustion air blower operated by a motor (M) which is configured to draw in combustion air during operation and supply the assembly (11) with the combustion air for generating heat.The air heater (2, 102) defines a longitudinal axis (L) extending through the heating air inlet (14) and the heating air outlet (22). The combustion air blower module (6, 106) is configured to support the outer housing (G). The outer housing (G) comprises a first housing element (8, 108) and a second housing element (18, 118) as separate components. The combustion air blower module (6, 106), the first housing element (8, 108), and the second housing element (18, 118) are assembled in an axial direction parallel to the longitudinal axis (L).

Description

Technical field:

[0001] The present invention relates to an air heater for mobile applications with axially mountable housing shells. Technical background:

[0002] Air heaters for mobile applications, particularly in vehicles or construction machinery, are conventionally fuel-based. In a combustion chamber, heat is released by means of fuel supplied from a tank. The hot combustion gases transfer some of their usable heat energy to heated air, which is supplied by a fan, in a heat exchanger. The air to be heated (also referred to as heated air in this document) is generally drawn over the heat exchanger by a fan, typically a single-walled outer casing. Such casings serve primarily to direct the airflow.

[0003] An outer casing can comprise one or more housing shells, usually made of plastic. The outer casing, or the corresponding housing shell, is mounted on the air heater in such a way that there is a slight gap to the outer fins, which extend outwards from the base of the heat exchanger. This gap creates one or more channels for the heated air, through which the fan can circulate the heated air. The outer casing, or the corresponding housing shells, essentially define the outer contour of the entire air heater.

[0004] The fins of the heat exchanger increase the contact area between the heat exchanger and the heated air in the relevant hot air duct and guide the heated air in individual flow channels between the fins. This ensures efficient heat transfer between the heat exchanger and the heated air. The heated air warms up along the resulting flow path and is then transferred to a downstream application, such as a hose system with one or more outlet openings in the vehicle's passenger compartment.

[0005] In the area of ​​the hot air blower, which is powered by a suitable impeller, the outer casing also serves as the blower housing. Between the hot air inlet and outlet, the hot air is guided aerodynamically through the outer casing along the heater. Furthermore, the pressure increase generated by the hot air blower, relative to the atmospheric pressure level in the vicinity of the heater, is supported. In the area of ​​the heat exchanger, the casing also provides thermal insulation. Specifically, it insulates the surrounding area from the high temperatures of the hot air and the heat exchanger fins.

[0006] A multi-part outer casing is not only suggested by the diverse functions of the outer casing, but primarily results from the requirements of the manufacturing process and the assembly of the air heater components, as well as potentially from the design. Outer casings with up to five casing shells, hereinafter also referred to as casing elements, are known.

[0007] DE 10 2021 112 943 A1 discloses an air heater having at least three housing shells. The outer housing comprises a housing body made up of two housing body sections arranged successively along the longitudinal axis of the housing. The first housing body section consists of a main housing part and a housing cover, through which the interior of the heater housing can be accessed from an oblique angle above or from the side. The second housing body section, which is essentially only formed at the rear end face of the air heater, includes the heating air outlet and can be attached in different positions to allow the outlet to be angled. It is formed in one piece and, like the two-part first housing body section, is made of a plastic material.

[0008] However, this design does have several disadvantages. For example, the assembly effort is comparatively high due to the three, and in some cases up to five, individual parts. Furthermore, the complex assembly with two main joining directions (e.g., axial and lateral radial) results in increased costs. The multiple parts also create large gaps due to the numerous joining points, potentially leading to increased hot air leakage, which must be compensated for by higher electrical drive power requirements. Additionally, the greater number of parts increases the likelihood of aerodynamically problematic positioning of edges and gaps, particularly in the exhaust area from the hot air blower. Complex tolerance chains for the hot air blower impeller must also be considered, as well as the low mechanical stability, especially in the inlet and outlet hoods.Overall, this results in a design with varying gap dimensions and low tactile robustness. Description of the invention:

[0009] The present invention is therefore based on the objective of providing an air heater in which the assembly effort is significantly reduced. Furthermore, it aims to increase the stability of the outer casing, reduce gaps between casing parts, improve the tolerances between the casing and functional parts such as the heating air blower or heat-conducting parts, and keep leakage and flow resistance of the heating air to a minimum.

[0010] According to the invention, an air heater for mobile applications, e.g., for a vehicle, is proposed, which may in particular be a fuel-based air heater. Vehicles are understood to include passenger cars, commercial vehicles, motorhomes, trailers for passenger cars or commercial vehicles, or caravans, construction machinery, or motor- or sail-powered ships or houseboats, etc., and the invention is not limited to specific applications.

[0011] The air heater comprises a heat generation unit and a heat exchanger that thermally interacts with this unit. The heat exchanger is designed to absorb the heat energy generated by the unit and transfer it to a medium, in particular heated air.

[0012] For this purpose, the air heater also has an outer casing that houses the assembly and the heat exchanger. The outer casing and the heat exchanger can form a heating air duct between them, for example, defined by an inner wall of the outer casing and an outer wall of the heat exchanger. In this heating air duct, the heated air can be guided over or past the heat exchanger to absorb heat from it. To form the heating air duct, the outer casing can be spaced apart from the heat exchanger. The outer casing can also define the outer boundaries of the heating air duct.

[0013] The air heater further comprises a hot air blower configured to draw in heated air through a hot air inlet in the outer casing and convey it along a flow direction through at least one hot air duct, and to discharge the heated air through a hot air outlet in the outer casing. In a preferred embodiment, the hot air blower is positioned upstream of the hot air duct (against the flow direction). This can thermally relieve the drive or motor of the hot air blower, as well as a corresponding impeller and its bearings. The hot air inlet and the hot air outlet form openings in the outer casing. The air heater defines a longitudinal axis L extending through the hot air inlet and the hot air outlet. The fact that hot air ducts may bend at the hot air outlet and are no longer considered part of the outer casing is harmless.Since the hot air blower and the combustion air blower are usually driven by a common motor and the impeller of the hot air blower should be arranged symmetrically behind the hot air inlet, the longitudinal axis thus defined usually coincides with the drive shaft of the motor or is at least parallel to it.

[0014] Furthermore, the heating unit also includes a combustion air blower module, which comprises a motor-driven combustion air blower designed to draw in combustion air during operation and supply it to the heat-generating assembly. The combustion air blower module can consist of several individual components, which, among other things, assemble the combustion air blower. The combustion air blower can advantageously be a side-channel compressor. In such a case, the combustion air blower module includes, for example, the two housing parts forming the channel, as well as the corresponding impeller, etc.

[0015] According to a first aspect of the invention, the combustion air blower module is configured to support the outer casing. This means that, after assembly, the outer casing and the combustion air blower module form a stable unit. It is not excluded that further points of contact exist between the outer casing and functional components of the air heater, e.g., in the area of ​​the heat exchanger, such as heat-insulating and / or mechanically acting damping elements or spacers, etc. However, preferably only the connection between the combustion air blower module and the outer casing fulfills the requirements for the mechanical stability and integrity of the device.

[0016] The outer casing can have a single- or multi-layered construction. This means that there can certainly be two or more casing layers which – complementing each other – form an interior space in which (among other things) the heat generation assembly and the heat exchanger are housed. The outer casing comprises at least a first casing element and a second casing element as separate components, which are assembled during the assembly of the air heater and thereby enclose the functional components of the air heater.

[0017] According to the present aspect of the invention, it is now proposed to snap the first housing element and the second housing element together in the axial direction parallel to the longitudinal axis by at least one, preferably two, snap-fit ​​connection(s). In other words, the two housing elements are attached in one and the same direction (including the opposite direction) during assembly of the air heater, namely along the longitudinal axis of the air heater. It is assumed that a snap-fit ​​connection more or less unambiguously defines an engagement direction that corresponds to the mounting direction of the corresponding housing part and, in this case, coincides with or is parallel to the longitudinal axis.

[0018] According to this aspect of the invention, the combustion air blower module thus provides a central connecting element or anchor point for the two housing elements, which, according to exemplary embodiments, can be an air inlet hood and an air outlet hood - i.e., two housing elements, one of which can have the heated air inlet and the other the heated air outlet.

[0019] In particular, according to exemplary embodiments, it can be provided that a housing part of the combustion air blower module is adapted in its design in such a way that a stable anchor point is created for the two housing parts, which can then be mounted in the same direction (or opposite directions) along the heater axis or longitudinal axis after pre-assembly of all other components of the heater.

[0020] According to exemplary embodiments, the two housing elements can thus be attached to the combustion air blower module via a robust locking mechanism at an anchor point, which improves mechanical stability. The combustion air blower module itself can provide a third housing element to which the two housing elements are locked.

[0021] According to an alternative, particularly preferred embodiment, the two housing elements can be directly interlocked without a third housing element, while both are jointly supported by the combustion air blower module.

[0022] Overall, according to this aspect of the invention, the tolerance chains to be considered during the design process are significantly simplified by the reduced number of parts (two housing elements instead of three or more). This also results in a reduction of joining gaps, and in particular the elimination of gaps in the area of ​​the outflow from the hot air blower located upstream of the device. This leads to a significant reduction in hot air leakage and, consequently, an improved volumetric efficiency of the hot air blower. The aerodynamic improvement also leads to a reduction in aeroacoustic noise sources (especially jet noise and vortex noise) and thus improves the overall acoustic properties of the air heater.

[0023] A particularly noteworthy advantage is that, unlike the previously described state of the art, the components of the air heater now only require assembly in essentially a single direction. In other words, one main assembly direction is eliminated. This simplifies assembly during manufacturing and also improves ease of maintenance when installed. Furthermore, the proposed design allows access to the impeller of the heating air blower and the control unit without extensive disassembly of the device components, for example, by simply unclipping and removing a single housing element.

[0024] A further advantage can be that, according to specific embodiments, a (second) housing element, designed as an air outlet hood, is provided, for example, made of closed-cell foamed plastic, thus significantly improving the thermal insulation of the housing in the area of ​​the heat exchanger. The outer housing, which can be assembled along its longitudinal axis, allows for the creation of two housing elements: one that covers the heat exchanger in the axial direction and the other that houses the electronics and the hot air blower. This makes it advantageous to adapt the two housing elements specifically to the prevailing requirements (temperatures, mechanical damping, strength or elasticity due to thickness, etc.).

[0025] Specific embodiments may provide that the combustion air blower module includes a frame integrally formed with a one-piece combustion air blower housing component, to which a third housing element, as mentioned above, is attached externally. This frame holds the third housing element from the inside, to which the first and second housing elements are snapped. The connection between the frame and the third housing element can be of any type, in particular positive locking, bonding, overmolding, or frictional locking, etc. The third housing element is considered part of the combustion air blower module. The third housing element and the combustion air blower housing component can be prefabricated and provided as a single component during assembly. The outer frame allows for electrical feedthroughs between itself and the combustion air blower to form the heating channels. Such an embodiment is described further below.The advantage can be a particularly stable construction. However, this frame requires further manufacturing steps, such as milling, to provide the necessary cable entry points and openings for the snap-fit ​​connections between the housing elements.

[0026] According to a further development of the first aspect of the invention, the combustion air blower module therefore comprises, in addition to such a one-piece combustion air blower housing component, which at least partially forms the combustion air blower, a number of mounting elements extending essentially radially away from the longitudinal axis and supporting the outer housing from the inside. This makes it possible to omit the continuous outer frame. Additionally, the third housing element can also be omitted, since the mounting elements press from the inside only against the first housing element, only against the second housing element, or – preferably – against both housing elements simultaneously.

[0027] Eliminating the combustion air blower frame results in a significantly simpler combustion air blower housing component – ​​in the case of die casting. For example, approximately 30% less material may be required, and the material can be distributed much more easily within the mold. A central gating point in the mold is preferred for the combustion air blower housing component. However, it has been observed that an external frame can lead to unfavorable material flow within the casting tool due to poor distribution of the molten casting material from the center of the mold into the frame. These problems are avoided by using support elements that extend from the combustion air blower, which is positioned centrally around the longitudinal axis.Furthermore, as described, the number of parts can be further reduced (the third housing element can be omitted, thus eliminating another joining gap and consequently further reducing hot air leakage, etc.).

[0028] This measure allows the combustion air blower to be cast in a multi-cavity die-casting tool. Milling operations for the snap-in clip connections and cable exits are eliminated. This results in a reduction in the cost of the individual part as well as a reduction in tooling costs over the entire product lifecycle.

[0029] Furthermore, additional mounting elements, such as the bracket / fastening of the relevant control unit (ECU), can be integrated into the same casting for the combustion air blower. This results in further cost optimization in manufacturing, logistics, and maintenance due to a reduced number of individual parts.

[0030] According to a specific embodiment, at least four of the mounting elements are provided. This allows, for example, the four corners and / or the four surfaces of the housing elements to be supported in the case of the typical square cross-sectional profile of the outer housing, so that a high degree of stability and mechanical integrity is achieved with minimal material usage.

[0031] According to a further development of the aforementioned embodiments, each of the mounting elements comprises a web extending outwards from a housing section of the combustion air blower housing component and a support section contacting the outer housing. According to a further refinement, the support section contacting the outer housing can form a free end of the corresponding mounting element. This design allows the support section to assume a foot-like structure, distributing the supporting force locally over an area on an inner wall of the corresponding housing element.

[0032] In the state where the first and second housing elements are locked together, the support section contacting the outer housing can optionally contact and support both the first and second housing elements. This option can advantageously prevent unintentional loosening and ensure the stability of the locking mechanism.

[0033] According to one embodiment based on this, the first housing element and / or the second housing element can have a receiving section formed on an inner wall of the respective housing element. The receiving section can extend axially from an edge surface where the first housing element and / or the second housing element face each other in the assembled state. In this case, the receiving section can be configured to receive the support section, which contacts the outer housing, in a sliding manner in the axial direction up to a stop surface.

[0034] According to a further development, both the first and second housing elements can each have a receiving section that, in the assembled state, faces each other axially and defines a common receiving area. This area, through positive locking with the support section, determines the axial position of the retaining element. Optionally, a snap-fit ​​connection (locking connection) of the housing elements with, for example, the foot-like contact section can also be provided in this context (optional embodiment not shown below).

[0035] According to a further development of the air heater, both the first and second housing elements can each have a substantially square or rectangular cross-sectional profile in a plane perpendicular to the longitudinal axis, as mentioned above. Each support section contacts and supports one of the four corners of the cross-sectional profile of the first and / or second housing element. Optionally, the arrangement can be configured such that the entire assembly of support elements forms an X-shaped structure when viewed along the longitudinal axis. This achieves a particularly high degree of stability with a small number of support elements.

[0036] According to one embodiment of the air heater, the combustion air blower housing component is a die-cast part, preferably made of aluminum or an alloy thereof. Additionally or alternatively, both the first housing element and the second housing element can each be one-piece molded plastic parts. Preferably, the one-piece molded housing elements each comprise at least one receiving section, preferably several receiving sections, which are integrated into the plastic molded part.

[0037] According to one aspect of the above inventive concept, a corresponding method for assembling an air heater as described above is also provided to solve one or more of the underlying problems. The method comprises the following steps: Providing the assembly for generating heat, the heat exchanger element thermally interacting with it, the combustion air blower module and the heating air blower, preferably in a pre-assembled state; Positioning the first housing element and the second housing element in opposite axial directions parallel to the longitudinal axis; Locking the first housing element and the second housing element together or with the combustion air blower module.

[0038] Further advantages and features relating to these first aspects of the invention will become apparent from the following detailed description of exemplary embodiments.

[0039] Some of the tasks mentioned at the beginning are also solved by an air heater according to a further aspect. Similar to the first aspects, this one assumes an air heater, in particular a fuel-based air heater, for a vehicle, comprising a heat-generating assembly, a heat exchanger element thermally interacting with the assembly, and a combustion air blower module. This module has a combustion air blower driven by a motor (M), which is configured to draw in combustion air during operation and supply it to the heat-generating assembly. Additional components mentioned above in the first aspects are also possible, in particular a hot air blower and an outer housing, which may, but does not necessarily have to, have the structure described above.

[0040] The air heater defines a longitudinal axis L extending parallel to a drive shaft of the motor. Since, as described above, such a axis in air heaters regularly coincides with, or at least lies close to and parallel to, the openings of the heated air inlet and outlet, there is no contradiction to the definition given above.

[0041] Furthermore, the air heater comprises the electric motor (M) for driving the combustion air blower, a control unit (ECU: electronic control circuit) for controlling the motor, and a mounting bracket for holding the control unit. Here, "control unit" refers to the entire unit, including electronic and mechanical components, which may consist of a control board equipped with a controller and electronic components, (internal) electrical wiring, connections, plugs, sockets, and, in particular, the housing with mounting elements, etc. The mounting bracket can be of any type in the general context of this document; however, its attachment and / or positioning on the combustion air blower module as described above is preferred.

[0042] A key characteristic of this aspect is that this control unit is equipped with at least one locking element as a mounting element, which interacts with a corresponding support element of the bracket in a snap-fit ​​connection to secure the control unit to the bracket. The basic idea is to replace the need to attach the control unit, which is typically mounted from the side during assembly of the air heater (i.e., radially perpendicular to the longitudinal axis), to the motor and / or the bracket of the blower module (or to the blower housing itself) using screw connections with threaded holes, with a simple snap-fit ​​connection. During installation, the control unit can thus simply be clipped into place.Investigations have shown that with appropriate design of the snap-fit ​​connections – possibly supported by the features specified in the training courses – sufficient robustness of the connection is achieved for use in vehicles, thus ensuring the durability of the air heater. Unlike fixing with screw connections, clipping on the heater eliminates the need for additional rotation of the heater in the assembly line. No additional fixture is required for this purpose; rather, the air heater can remain in the workpiece carrier in the main assembly direction throughout, reducing production time, costs, and the number of parts. The control unit can then be mounted to the blower housing or a correspondingly designed bracket with simple hand movements. Additional mounting elements such as screws are not required.

[0043] According to a further development of the present aspect of the invention, the mounting comprises two support elements that extend from the combustion air blower module parallel to the longitudinal axis L. In this case, the control unit can be provided with at least two locking elements, preferably four locking elements, each of which interacts with one of the support elements, preferably two of which interact with each of the support elements. The position and orientation of the control unit on the mounting is significantly stabilized by two, but in particular four, separate locking connections.

[0044] One special design features two support elements formed as angled tabs. This offers a particularly simple construction, facilitating clip-on installation, while the angled design stabilizes the support elements against applied forces.

[0045] According to a corresponding embodiment, the combustion air blower module can comprise a one-piece combustion air blower housing component, which at least partially forms the combustion air blower. The corresponding support element can extend from this component parallel to the longitudinal axis L.

[0046] A particularly advantageous further development of this embodiment provides that the two support elements are formed integrally with the combustion air blower housing component. If the combustion air blower housing component is manufactured as a die-cast part, this saves on components. At the same time, the design, with, for example, parallel angled tabs, is fully compatible with die-casting in the same form. Furthermore, an additional assembly process involving screw fastening of the bracket can be eliminated.

[0047] According to one embodiment, the locking elements in the respective locking connection extend perpendicular to the respective support element and parallel to each other, in order to allow the control unit to be clipped onto the bracket during its mounting in a radially inward movement along the longitudinal axis. This further simplifies the assembly of the air heater.

[0048] The control unit, or ECU, can have a housing that contains the electronics (control board, controller, electronic components, wiring, etc.). Locking elements can extend from this housing. Preferably, they are integrally formed with the housing, for example, from a plastic material. This saves costs and effort and reduces the number of components.

[0049] Furthermore, the control unit housing can have a support projection or block with which it rests on the mounting element. When the control unit is clipped in place, this support projection and a locking lug of the locking element secure the mounting element between them in the direction perpendicular to the longitudinal axis. The support projection essentially forms the contact surface opposite the contact surface of the locking lug. The distance between these contact surfaces corresponds to the height of the mounting element in the locking direction. This ensures that the position of the control unit housing is clearly fixed in the vertical direction. The term "support projection" or "block" should not be interpreted too narrowly. It simply refers to a position of an area on the outer surface that is adapted to the control unit housing.

[0050] According to further embodiments of the air heater according to the invention, a first connector housing with exposed circuit board contacts is formed in the control unit housing. A second connector housing with exposed motor contacts is formed on a motor housing. The second connector housing is designed to be received in the first connector housing to establish an electrical connection between the circuit board contacts and the motor contacts. These measures eliminate the need for a separate power supply cable on the motor. Therefore, complex manufacturing, assembly, and routing of the cable are unnecessary. Instead, the motor contacts are directly connected to the outputs of the control board via the circuit board contacts.

[0051] A further development of this concept involves the second connector housing being inserted into the first when the motor is fixed to the combustion air blower housing component (this can be done conventionally using screws) and the control unit is clipped onto the bracket. The resulting positive fit secures the control unit, particularly in a transverse direction (perpendicular to the radial or clipping direction) of the air heater, for example, along the longitudinal axis L. The direct plug connection (without cable routing) provides additional fixation of the control unit housing within the air heater. In this example, the second connector housing protrudes from the motor, while the first connector housing is recessed into the surface of the control unit housing. The second connector housing can be molded as an injection-molded part within a motor bearing shield.

[0052] Optionally, a circumferential seal can be provided on the inside of the first connector basket or on the outside of the second connector basket, so that a space containing the contacting circuit board contacts and motor contacts within the two connector baskets is sealed against moisture and dirt.

[0053] Advantageously, the circuit board contacts can be mounted directly on a control board of the control unit and protrude into the first connector basket, which is recessed into the control unit housing. This saves space within the control unit housing and further reduces the number of components.

[0054] The concept of interlocking connectors on the motor and control unit offers several advantages: no additional cable needs to be mounted on the motor. Complex manufacturing, assembly, and routing of the cable are also unnecessary, as the motor contacts can be directly connected to the control board.

[0055] For radial sealing, only three components need to be coordinated: the internal geometry of the first connector housing in the control unit, the mounting of the rubber seal (e.g., on the outside of the second connector housing on the engine), and the seal itself. The component dimensions required for the seal can easily be manufactured within the general tolerances of the respective production processes. Therefore, additional reworking of the functional surfaces on the connector housings is unnecessary.

[0056] Furthermore, because the necessary radial forces for compressing the radial seal are applied by simply fitting the two parts together—depending on the design of the inner dimension of the first connector housing in relation to the outer dimension of the seal (e.g., made of rubber)—no additional pressing forces, such as those provided by screws, are required. Moreover, unlike an axial seal with a force-by-shaft connection, no precise stops are necessary in the joining direction (parallel to the clipping direction), as the radial seal allows for a sliding fit in this direction. This permits a significantly larger axial tolerance (considered here in the joining direction). Consequently, considerably more cost-effective connections between the control housing and the electric motor are possible. By clipping the control unit onto the bracket and then attaching it to the motor, any screws or similar fixings can be eliminated.

[0057] Further advantages and features relating to these second aspects of the invention will also become apparent from the following detailed description of exemplary embodiments. Brief description of the drawings:

[0058] The invention is explained below by way of example with reference to the following figures.

[0059] They show: Fig. 1 a schematic overview in longitudinal section view of a conventional fuel-operated air heater; Fig. 2 in perspective view a fuel-operated air heater according to a first embodiment during the attachment of the housing elements; Fig. 3 like Fig. 2, but in an enlarged view of the snap connections of the housing elements; Fig. 4 in perspective view a combustion air blower module of the air heater made of Fig. 2; Fig. 5 in perspective view the combustion air blower module from Fig. 4 without the outer (third) housing element; Fig. 6 in lateral longitudinal section view the fuel-operated air heater according to the first embodiment; Fig. 7 in perspective view the outer casing of the air heater made of Fig. 2 in the assembled or locked state; Fig. 8A,B in perspective view the combustion air blower module of the fuel-operated air heater according to the first embodiment ( Fig. 8A) and after ( Fig. 8B) the installation of a bracket for an electronic control unit; Fig. 9 in perspective view a fuel-operated air heater according to a second embodiment; Fig. 10A,B in axial top view ( Fig. 10A) and in perspective view ( Fig. 10B) a combustion air blower module of the fuel-operated air heater according to the second embodiment, with an integrated holder for an electronic control unit; Fig. 11 in perspective view the fuel-operated air heater according to the second embodiment before the attachment of the outer casing consisting of two casing elements; Fig. 12 like Fig. 11, but in perspective view a section perpendicular to a longitudinal axis through the structure of internal components of the air heater made of Fig. 9 (outer casing removed), with the view directed from the housing of the fuel blower (front) to the heating air blower (rear); Fig. 13 like Fig. 11, but with the first housing element attached; Fig. 14 like Fig. 12, but with the first housing element attached; Fig. 15A,B in enlarged perspective view excerpts of a recording section of the second housing element ( Fig. 10A) and the mounting element to be attached to the combustion air blower module; Fig. 16 a section through the second housing element in perspective view; Fig. 17 a section through the first housing element in perspective view; Fig. 18 like Fig. 12 or Fig. 14, but with a second housing element now also attached, wherein the section through the air heater according to the second embodiment is at the level of the combustion chamber; Fig. 19 in perspective view the combustion air blower module with attached motor and mounted control unit according to the second embodiment, viewed from a slant below; Fig. 20 like Fig. 19, but from a different perspective (from a slightly elevated angle); Fig. 21 in perspective view the electronic control unit or its control unit housing according to the second embodiment; Fig. 22 the combustion air blower module with attached motor in top view during clipping on or mounting of the control unit; Fig. 23 like Fig. 22, but with the control unit installed; Fig. 24 in enlarged view the locking element of the control unit in the state locked to the mounting of the combustion air blower module; Fig. 25A,B in cross-sectional view ( Fig. 25A) and in side view ( Fig. 25B) the electric motor of the air heater according to the second embodiment, with a second plug basket on the motor side; Fig. 26 in perspective view the control board with circuit board contacts attached to it for a first connector basket on the control unit side; Fig. 27 in perspective view from below the control unit with the first (recessed) connector basket arranged in the control unit housing; Fig. 28A,B in sectional view a state of the motor and the control unit before attachment (clipping on - Fig. 28A) and after the control unit has been installed; Fig. 29 in perspective view which in Fig. Circumferential seal for the plug baskets shown in Figures 28A and B; Fig. 30 in axial top view ( Fig. 30A) as well as in perspective view ( Fig. 30B) the interconnected parts control unit and engine. Detailed description of preferred embodiments:

[0060] In the following description of the drawings, identical reference numerals denote identical or comparable components. The features of the invention disclosed in the preceding description, in the drawings, and in the claims can be essential for the realization of the invention, both individually and in any combination.

[0061] The Fig. Figure 1 shows a schematic longitudinal section providing an overview of a conventional fuel-operated air heater 2, which illustrates the basic structure applicable to the embodiments. The air heater 2 is intended, for example, for use in a motor vehicle. The air heater 2 has an outer housing G with an intake opening or heating air inlet 14 for heated air H and an outlet opening or heating air outlet 22 for the heated air H. A combustion chamber housing with a fuel-operated combustion chamber 11 is located in a heat exchanger element 13 of the air heater 2. A combustion air blower, housed in a combustion air blower module 6 and designed as a side-channel compressor (not shown in detail), ensures the supply and flow of combustion air through the combustion chamber 11.The combustion air blower is connected to a laterally arranged combustion air inlet 9, through which it draws in the combustion air. Not shown in detail are a fuel supply line (but reference numeral 38 below), a vaporizer for the fuel, and an ignition device for starting a combustion process. In the combustion chamber 11, the fuel and the combustion air containing the oxidizer (e.g., oxygen) undergo a chemical reaction to generate heat.

[0062] The heated air H is drawn in from the environment via the heated air inlet 14 at one end of the air heater 2 by means of a heated air blower 3 and exits at the rear of the air heater 2 opposite the end, after flowing around the heat exchanger 13 in corresponding heated air channels through the heated air outlet 22.

[0063] A generally multi-part outer housing G surrounds the functional components of the air heater 2. In the area of ​​the heat exchanger element 13, the heating air channels are formed between the heat exchanger element 13 and an inner wall of the outer housing G. In a front area of ​​the outer housing G, the heating air H – not yet heated – flows around components such as the control unit ECU, the motor M, and the combustion air blower module 6 after passing through an impeller of the heating air blower 3. The heating air inlet 14 and the heating air outlet 22 of the air heater 2 form, purely by way of example, a common spatial longitudinal axis L of the air heater 2. Overall, the heating air H, driven by the heating air blower 3, flows accordingly along a direction R. Hparallel to the longitudinal axis L. The combustion air blower of the combustion air blower module 6 and the heating air blower 3 are jointly driven by a drive motor M, which is controlled by a control device ECU in a known manner, in particular depending on a requested heating power.

[0064] On one exhaust gas side of the heat exchanger 30, after combustion in the combustion chamber 11, hot combustion gases flow as an impact flow against a wall in a longitudinally rear region of the heat exchanger. Fig. Figure 1 shows the combustion chamber 11 in a purely schematic representation, and a flame tube, typically tapered in the direction of flow, can be connected to it. After leaving the combustion chamber or flame tube and passing through the impact flow against the wall of the heat exchanger, the combustion gases are sharply deflected by 180° and then flow towards the exhaust gas outlet 15 in the opposite direction to the flow of the heating air outside the heat exchanger 30. A heat exchanger constructed in this way can also be referred to as a counterflow heat exchanger.

[0065] The exhaust gases are routed through flow channels formed by fins (not shown) projecting inwards from an inner surface of the heat exchanger 13 and extending along the longitudinal axis L, thus improving heat transfer. Due to this design, the heat exchanger element 13 reaches its maximum temperature in the rear region during operation, decreasing from rear to front as heat transfer progresses. Accordingly, the heated air reaches its highest temperatures in the heated air channels near a rear region before being discharged from the heated air outlet 22. This configuration, as described above, is also applicable to the embodiments described below.

[0066] The Fig. Figures 2 to 8B show a first embodiment of a fuel-based air heater 2. Some differences are described below, for example, the Fig. 1 is explained, while reference is made to the above description regarding matching features.

[0067] The air heater 2 has an outer casing G made up of two casing shells, as shown in Fig. 2 can be seen. The two housing shells are designated here as the first housing element 10 and the second housing element 18. The first housing element 10 simultaneously forms an air inlet hood 12, which includes the heated air inlet 14, and the second housing element 18 simultaneously forms an air outlet hood 20, which includes the heated air outlet 22.

[0068] The Fig. Figure 2 shows the state of assembly of the housing shells, while the Fig. Figure 7 shows the assembled state of the outer housing G. For assembly, the two housing elements 10 and 18 are brought towards each other in assembly directions C1 and C2 parallel to and along the longitudinal axis L and locked together. The locking mechanism is provided by the in Fig. Four combustion air blower modules, shown in greater detail, are available. In its installed state, it is sandwiched between the two housing elements 10 and 18.

[0069] The combustion air blower module 6 comprises the actual combustion air blower, which, as in Fig. 4 is formed by a combustion air blower housing part 7. The combustion air inlet 9 extends into the combustion air blower. A frame 5, designed as a thin rib, extends around the outside, already anticipating the essentially square cross-sectional profile of the outer housing G. The frame 5 and the combustion air inlet 9 are formed in one piece with the combustion air blower housing part 7 as die-cast aluminum. The frame 5 is connected via in Fig. The 5 webs 55 shown are connected to the combustion air blower housing part 7. Flow openings 53 are located between the frame 5, the webs 55 and the combustion air blower housing part 7 (see also Fig. 5) for the heating air H, so that the heating air can pass from a front part of the air heater 2 to a rear part containing the heat exchanger element 13. The frame 5 supports a narrow third housing element 4 over a large area on the outside, which, like the housing elements 10 and 18, can be made of injection-molded plastic. Two openings are formed on opposite sides of the third housing element 4, serving as the first locking elements 26, which will be explained below.

[0070] In Fig. Figure 3 shows a detailed snap-fit ​​connection 24 between the third housing element 4 and the first housing element 10 on the one hand, and the second housing element 18 on the other. During assembly, the first housing element 10 faces a front face 16 of the third housing element 4, while the second housing element 18 faces a rear face 8 of the third housing element 4. Both housing elements 10 and 18 have elastic tabs 27, each with projections forming second snap-fit ​​elements 28. These projections can engage with the corresponding openings of the first snap-fit ​​elements on the side of the third housing element 4 by means of the elastic tabs 27 when the first and second housing elements are pushed towards each other along the axial directions C1 and C2 onto the third housing element 4 of the combustion air blower module 6.In its assembled state, the combustion air blower module 6 completely supports or carries the outer housing G, which is made up of two shells.

[0071] This housing design of the air heater 2 according to the first embodiment enables a continuous axial alignment of the workpiece carrier during manufacturing, without requiring rotations of, for example, 90 degrees.

[0072] The Fig. Figure 6 shows a longitudinal section through the air heater 2 according to the first embodiment. Reference numeral 32 indicates an electrical line that supplies power to the air heater. Corresponding cable glands in the outer casing are shown in the Fig. 2, Fig. 4 and Fig. 7 not shown for the sake of clarity, but is generally available.

[0073] In the Fig. Figure 5 shows an alternative embodiment of the combustion air blower housing component. In this figure, milled openings 52 for the cable exits are shown in the frame 5 at the corresponding position. Also shown are mounting holes 51 for attaching the first and second housing elements to the frame 5.

[0074] These milled sections represent additional process steps, and a total of four snap-fit ​​connections 24 are required (two snap-fit ​​connections on each of the two opposite sides of the air heater 2) to achieve a stable outer housing configuration. Furthermore, as described in the Fig. 8A and Fig. As shown in Figure 8B, an additional bracket is required for the ECU control unit, which is intended to control the motor M. This requires additional mounting parts (screws, separate bracket) and yet another assembly step. Furthermore, as described at the beginning, the die-casting process for the combustion air blower housing component 7 places high demands on the frame, even though it is to be manufactured as a single piece with this component. The anchor point for the mold is located in the area of ​​the shaft bearing, which passes through the bore 71 for the shaft 31 of the electric motor M. Fig. 5 is indicated.

[0075] Starting from the one in the Fig. Therefore, in relation to the concept of the first embodiment shown in Figures 2 to 8B, a second embodiment was designed which also provides solutions and further improvements for these points mentioned.

[0076] The Fig. Figure 9 shows a perspective view of a fuel-operated air heater 102 according to the second embodiment. It should be noted that the flow direction R H the heated air H in the Fig. 9 to 30B concerning the second embodiment from right to left. Similar to the first embodiment, the outer housing G also has a two-part housing structure, with a first housing element 110 and a second housing element 118, which again correspond to a hot air inlet hood 112 with hot air inlet 14 and an air outlet hood 120 with hot air outlet 22. The basic functional internal structure of the air heater 102 is the same as with reference to Fig. 1 described. Seen in Fig. 9 the combustion air inlet 9, the exhaust gas outlet 15 and the fuel supply line 38.

[0077] A cable penetration (without markings) can be seen slightly above the combustion air inlet 9. Further up in Fig. 9 contains a locking connection 124, which is now formed directly between the first housing element 110 and the second housing element 118. On the side of the second housing element 118, it comprises an opening formed in its wall as the first locking element 126, and on the side of the first housing element 110, a projection formed on an outer surface of the first housing element 110 as the second locking element 128. As in the first embodiment, the locking elements 126, 128 form a positive fit when locked. As in the Fig. As shown in Figure 17, which depicts a longitudinal section through the first housing element 110, the projecting second locking element 128 is formed on an elastic tab 127, so that the locking process with the first locking element 126 can be carried out more easily. Both locking elements 126 and 128 are elongated, so that locking is only possible when the two housing elements are brought towards each other axially along the longitudinal axis L (which here, for example, is defined by an axis running through the heating air inlet and outlet, or equivalently by an axis running along the shaft of the blower motor M).

[0078] This design achieves at least the same advantages as the first embodiment, namely, among other things, an axial mounting direction for all housing halves and a reduction in their number. Furthermore, the corresponding combustion air blower module 106 of the second embodiment can also be simplified, since the third housing element 4, which serves as a docking element, is eliminated. This also reduces the number of snap connections from four to two (one snap connection on each of the two opposite sides of the air heater). Furthermore, as a comparison of Fig. 7 and Fig. As can be seen in Figure 9, the number of joining gaps F is reduced from two to one. Consequently, the hot air leakage from inside the air heater 102 is also reduced.

[0079] The combustion air blower module 106 according to the second embodiment is in Fig. 10A and Fig. Figure 10B shows that, compared to the first embodiment, not only is the third housing element 4, which is part of the combustion air blower module 106, omitted, but also the frame 5. Instead, the second embodiment provides mounting elements 105 that extend radially outwards from a section of the combustion air blower housing component 107. As is best illustrated in the Fig. As can be seen in Figure 14, these mounting elements 105 support or carry the outer housing G, or in the state of Fig. 14 the first housing element 110. The mounting elements 105 comprise a web section 152 and a contact section 151, which is designed as a foot to abut an inner wall 202 or 122 (see Fig. 16 and Fig. 17) to support the first housing element 110 and the second housing element 118.

[0080] The combustion air blower module 106 further comprises a bracket 140, integrally formed with the combustion air blower housing component 107 and explained below, as well as bores 171 for fastening the combustion air blower housing component 107 to other components, such as the heat transfer element 13, in the axial direction. Reference numeral 71 again designates the bore for the bearing of the blower motor shaft M. Threaded bores 172 serve to mount the blower motor M, also in the axial direction.It should be noted that, for stability reasons, the mounting elements 105 have web sections which also extend radially across the combustion air blower housing component 107 into its central area, so that, because the mounting elements 105 extend into the four corners of the generally square cross-sectional profile of the outer housing G, an X-shaped configuration results in axial plan view (along the longitudinal axis L), as shown in . Fig. 10A is particularly easy to spot.

[0081] The Fig. Figure 11 shows the air heater 102 with the outer casing G not yet mounted. These are the ones already mentioned in relation to Fig. The components described in section 1 can be identified. Reference numeral 131 designates a sealing plate (part of the heat transfer element) that covers an area on the underside of the air heater 102. It is integrally formed with the heat transfer element 13 and is therefore not an injection-molded plastic part but made of metal and is specifically connected to the exhaust gas outlet 15. It closes an area not covered by the housing elements 110 and 118 and thus seals the interior of the outer housing G from the outside. Reference numeral 173 designates a fastening element for the bore 172 (see Fig. 10A).

[0082] The Fig. 12 shows the same state as Fig. Figure 11 shows a different perspective, but with a cross-section through the air heater, revealing the combustion air blower housing component 107 and, in particular, the side channel impeller housing. The shaft 31 for the blower motor is also visible here. The impeller of the hot air blower 3 is located in the background.

[0083] The Fig. 13 and Fig. Figure 14 shows the state during the assembly process after the first housing element 110 has been attached, both in perspective side view and section view. The mounting elements 105 brace against the four corners of the cross-sectional profile of the first housing element 110, but protrude from the opening of the attached first housing element 110 in the axial direction along the longitudinal axis L.

[0084] The Fig. Figure 15A shows, as an example, one of the corners of the second housing element 118 in an enlarged view. The corresponding corner of the in Fig. The first housing element 110 shown in Figure 14 has essentially corresponding features. The only special feature of the second housing element 118 in this respect is a collar section 181 which, when mounted to the first housing element 110, extends slightly over its outer surface.

[0085] Ribs 190, 209 are located in the corners and edges of both housing elements (see below). Fig. 15 and Fig. 16) formed, one of which is shortened towards the outer edge to provide a receiving section 188 for the contact section 151 of the retaining element 105 and to form a stop surface 186 that limits the position of the contact section 151 in the interior of the second housing element 110. This applies analogously to the first housing element 110. For this reason, the first housing element 110 can be Fig. 14 cannot be pushed further, so that the retaining element 105 protrudes halfway.

[0086] In Fig. Figure 15B shows an enlarged representation of a mounting element 105. The foot-shaped contact section 151 has two opposing stop surfaces 159, one of which, in the assembled state, is connected to the Fig. The contact surface 15A shown in section 15A abuts the stop surface 186, and the other contact surface 15A abuts the corresponding stop surface (not shown) in the first housing element 110. Furthermore, the foot-like contact section 151 has two lateral contact surfaces 156, 157 with which it contacts receiving surfaces 184, 185 of the outer ribs 190 (209 analogously). In this way, a positive fit is established between the contact section 151 and the receiving section 188. Fig. 15A analog recording section 208 on the side of the first housing element 110 is achieved (see Fig. 17).

[0087] The second housing element 118 is then attached, as shown in Fig. Figure 18 shows (the section through the air heater is shown here extending further back, and the second housing element 118 is visible all around at the front). Here, the part of the contact section 151 of the mounting element 105, which still protrudes from the first housing element 110, enters the corresponding receiving section 188 of the second housing element 118. In this state, the receiving sections 188 and 208 are contacted by the contact surface 158 of the foot-like contact section 151. Due to the X-shaped design of the four mounting elements 105, the foot-like contact sections 151 slide precisely into the receiving sections 188, 208 of the corresponding opening of the respective housing element 110, 118 during assembly, until the associated stop surfaces 186, 159 of the foot-like contact section 151 and the two housing elements 110, 118 meet.In the state in which the snap-fit ​​connections 124 are established, the four stop surfaces 186, 159, etc., contact each other, thus fixing the axial position of the housing elements 110, 118 relative to the combustion air blower module 106. The positive locking of the X-shaped structure also prevents rotation of the outer housing about the longitudinal axis L. It should be noted that only two snap-fit ​​connections 124 are sufficient for this purpose, and no additional screw connections are required.

[0088] The Fig. 19 and Fig. Figure 20 shows a perspective view of the combustion air blower module with the attached motor M and the mounted control unit ECU according to the second embodiment, viewed from an oblique angle below and from an oblique angle above. The electric motor M is attached directly to the combustion air blower module 106 by means of screws (see the bores 172 in Figure 20). Fig. 10A). The control unit ECU is attached to the bracket 140 by clipping it on from the side using four snap-fit ​​connections 300 (see Fig. 24).

[0089] The bracket 140 comprises two angled tabs extending linearly and parallel to each other along the longitudinal axis L from the combustion air blower housing part 107, which have a vertical section (first angled surface 142) and a horizontal section (second angled surface 144). The sections 142 and 144 are, for example, perpendicular to each other, cf. Fig. 24. The angle tabs can be manufactured in one piece with the aluminium die-casting of the combustion air blower housing part 107, which further reduces the total number of components.

[0090] The Fig. Figure 21 shows the ECU control unit in greater detail. It comprises an ECU housing 210, which has a cover 212 and a housing base 214. The design of the ECU housing 210 is generally flat to accommodate a Fig. The control board 260 shown in Figure 26 is to be mounted. The control board 260 defines a plane within the control unit housing 210, with one direction A of clipping the control unit housing 210 being perpendicular to this plane. On the lower part of the housing 214, several connector sockets 218 are arranged in the clipping direction A, which enable an electrical connection of the control unit ECU to the vehicle's electrical system (communication and power supply), see also the cable passage K into the housing discussed above. Fig. 13, Fig. 16 and Fig. 17 and electrical line 32 in Fig. 6 concerning the first embodiment.

[0091] In particular, four locking elements 220 extend – also in the clipping direction A – parallel to each other from the lower housing part 214. As shown in the enlarged illustration of the Fig. As can be seen in Figure 24, each of these comprises a flexible locking arm 222 and a locking lug 224. Each locking element and one of the two angled tabs of the holder 140 form a locking connection 300. Two locking lugs 224 of the locking elements face each other, so that when clipped onto the holder 140, the locking elements 222 grip the angled tabs on the outside, the locking arms 222, in the locked state, conform to the vertical sections (angled surfaces 142) from the outside, and the locking lugs engage a distal end of the vertical sections (angled surfaces 142) so that the control unit housing 210 can no longer detach against the clipping direction A. Furthermore, on the underside of the lower housing part 214, support projections 215 are provided which, in a state in which the locking lugs 224 engage under the angle tabs of the holder 140, contact the same angle tabs from above and thereby limit further movement in the clipping direction A.Thus, the ECU is fixed in the clipping direction A by positive locking, which is perpendicular to the extension direction of the angled tabs and to the longitudinal axis L. The clipping process is described in the... Fig. 22 and Fig. 23 shown.

[0092] The Fig. Figure 27 shows the underside of the lower housing part 214 of the control unit housing 210 in greater detail. In addition to the laterally arranged, raised connector sockets 218 for connection via plugs with cables or electrical leads, a first connector cage 260 is provided in the central position as a recess in the surface of the lower housing part 214. Three circuit board contacts 262, designed as fork-shaped contacts, protrude from the interior of the control unit housing 210 into this first connector cage 260. The fork shape establishes a flexible and reliable connection to the, for example, pin- or plate-shaped motor contacts 250. The circuit board contacts 262 are, as shown in Fig. As can be seen in Figure 26, the connector is mounted directly on the circuit board and connected to electronic components provided there, which enable the control and operation of the motor M. Adjacent to the first connector cage 264, a cylindrical recess 217 is provided in the surface of the lower housing part 214, the shape of which is complementary to the cylindrical housing of the electric motor M (see, e.g., Figure 26). Fig. 19).

[0093] The Fig. 25A and Fig. 25B shows in cross-sectional view ( Fig. 25A) and in side view ( Fig. 25B) the electric motor M of the air heater M according to the second embodiment. The motor M has three motor contacts 250 for connecting, for example, the three phases of the motor M. The motor contacts 250 are arranged within a motor-side second connector basket 240, which is injection-molded together with a motor bearing shield 244 and has a shape and external dimensions such that it fits precisely into the recess of the first connector basket 264.

[0094] The Fig. 28A and Fig. Figure 28B shows the connection between the electric motor M and the control unit ECU. One in Fig. The sealing ring 242 shown in Figure 29 is positioned on an outer edge of the second connector basket 240 to seal an interior formed by both connector baskets 240, 264 when they are plugged together. Fig. 30A and Fig. Figure 30B shows the assembled state of engine M and control unit ECU from different perspectives. The combustion air blower module 106 is hidden from view.

[0095] The Fig. 22 and Fig. Figure 23 shows the clip-on process including the combustion air blower module 106 with the bracket 140. The magnification of the Fig. 24 is to be used for this purpose. Clipping on to create the snap-fit ​​connection 300 is accompanied by inserting the second motor-side connector basket 240 into the first control unit-side connector basket 264. The latter connection secures the control unit positively, particularly in a direction perpendicular to the clipping direction A, e.g., along the longitudinal axis L, thus preventing, for example, the control unit from sliding along the angled tabs. Overall, this gives the control unit a mechanically stable and reliable position without the use of screw connections.

[0096] It should be noted that, although the designs of the Fig. Sections 9 to 18 on the one hand and 19 to 30B on the other hand relate to the same embodiment, are independent improvements, and can each be implemented without the other improvement; therefore, they are considered above to be different aspects of the invention. Nevertheless, synergistic effects due to the combination are obviously not excluded. Reference symbol list 2 air heaters 3 hot air blowers 4 Third housing element 5 Mounting element for the outer housing (frame construction) 6 Combustion air blower module 7 Combustion air blower housing part 8 Rear (third housing element) 9 Combustion air intake 10 first housing element 11 burners 12 Air intake hood 13 Heat transfer element 14 Heated air inlet 15 Exhaust outlet 16 Front (third housing element) 18 second housing element 20 air outlet hoods 22 Heated air outlet 24 rest connection 26 first locking element 27 elastic tabs 28 second locking element 30 electrical connection 31 Shaft (blower motor) 32 electrical lines 34 Support structure 36 Heating module 38 Fuel supply line 51 mounting holes 52 openings for cable exits 53 Flow opening (for heated air) 55 radial struts 56 Mounting bracket for control unit 57 screws for attaching the bracket 71 Bore in combustion air blower module for shaft 102 Air heater 105 mounting elements for the outer casing 106 Combustion air blower module 107 Combustion air blower housing part 110 first housing element 112 Air intake hood 118 second housing element 120 air outlet hood 122 Interior wall (air outlet hood) 124 rest connection 126 first locking element 127 elastic tabs 128 second locking element 131 Sealing plate (part of the heat transfer element) 140 Control unit mounting bracket (support tabs) 141a, b Angle bracket 142 first angular surface 144 second angle surface 151 Support section 152 radial bridge 156 contact area 157 Contact area 158 contact area 159 Stop surface (in axial direction) 171 holes for mounting the heat transfer element 172 holes for mounting the motor 173 Fasteners for drill holes 171 181 Collar section 184 Recording area (in circumferential direction) 185 Recording area (in circumferential direction) 186 Stop surface (air outlet hood, in axial direction) 188 Recording section (air outlet hood) 190 ribs (air outlet hood) 202 Interior wall (air intake hood) 206 Stop surface (air inlet hood, in axial direction) 208 Intake section (air intake hood) 209 ribs (air intake hood) 210 control unit housings 212 lids 214 Lower housing part 215 circulation advantage 216 Lid fastening 217 Recess in lower housing for cylindrical motor housing 218 connector sockets (control unit) 220 locking elements (control unit) 222 Raster arm 224 Rastnase 240 Connector basket (motor) 242 Seal on motor-side connector 244 Engine Mount Shield 250 motor contacts 260 control board 262 fork-shaped circuit board contacts 264 Connector basket (control unit) 300 rest connection A lateral mounting direction (radial direction) C1, C2 Mounting directions for the housing elements ECU control unit F joint G Outer casing H Heated air K cable passage L Longitudinal axis M Motor R H general direction of the heating air flow QUOTES INCLUDED IN THE DESCRIPTION

[0000] This list of documents cited by the applicant was automatically generated and is included solely for the reader's convenience. The list is not part of the German patent or utility model application. The DPMA accepts no liability for any errors or omissions. Cited patent literature

[0000] DE 10 2021 112 943 A1

[0007]

Claims

[1] Air heater (2, 102), in particular a fuel-based air heater, for a vehicle, comprising: a component assembly (11) for generating heat; a heat exchanger element (13) that thermally interacts with the assembly (11); an outer housing (G) that accommodates the assembly (11) and the heat exchanger element (13), wherein the outer housing (G) and the heat exchanger (30) form a hot air duct (39) between them; a hot air blower (3) which is configured to draw in hot air (H) via a hot air inlet (14) of the outer casing (G) and to direct this air along a flow direction (R) H ) to convey through the hot air duct (39) and to discharge via a hot air outlet (22) of the outer casing (G); a combustion air blower module (6, 106) comprising a combustion air blower operated by a motor (M), which is configured to draw in combustion air during operation and to supply the assembly (11) for generating heat with the combustion air, wherein the air heater (2, 102) defines a longitudinal axis (L) extending through the heating air inlet (14) and the heating air outlet (22). characterized by , that the combustion air blower module (6, 106) is set up to carry the outer housing (G); the outer casing (G) comprises a first casing element (8, 108) and a second casing element (18, 118) as separate components; and the combustion air blower module (6, 106), the first housing element (8, 108) and the second housing element (18, 118) are assembled in an axial direction parallel to the longitudinal axis (L). [2] Air heater (102) according to claim 1, wherein the first housing element (8, 108) and the second housing element (18, 118) are locked together in the axial direction parallel to the longitudinal axis (L) by at least one, preferably two, locking connection(s) (124). [3] Air heater (102) according to claim 1 or 2, wherein the combustion air blower module (106) comprises a one-piece combustion air blower housing component (107) which at least partially forms the combustion air blower; and the combustion air blower housing component (107) has a number of support elements (105) extending substantially in a radial direction (A) away from the longitudinal axis (L) and supporting the outer housing (G) from the inside. [4] Air heater (102) according to claim 3, wherein at least four of the mounting elements (105) are provided. [5] Air heater (102) according to one of claims 3 or 4, wherein each of the retaining elements (105) comprises a web (152) extending outwards from a housing section of the combustion air blower housing component (107) and a support section (151) contacting the outer housing (G). [6] Air heater (102) according to claim 5, wherein the support section (151) contacting the outer housing (G) forms a free end of the corresponding retaining element (105). [7] Air heater (102) according to claim 5 or 6, wherein in the state in which the first housing element (8, 108) and the second housing element (18, 118) are locked together, the support section (151) contacting the outer housing (G) in each case contacts and supports both the first housing element (108) and the second housing element (118). [8] Air heater (102) according to one of claims 5 to 7, wherein the first housing element (108) and / or the second housing element (118) have a receiving section (188, 208) which is formed on an inner wall (122, 202) of the housing element in question, wherein the respective receiving section (188, 208) extends in the axial direction from an edge surface where the first housing element (108) and / or the second housing element (118) are opposite each other in the assembled state, wherein the respective receiving section (188, 208) is designed to receive the support section (151) which contacts the outer housing (G) in an axially sliding direction, preferably up to a stop surface (186, 206). [9] Air heater (102) according to claim 7, wherein both the first housing element (108) and the second housing element (118) each have a receiving section (188, 208) which are opposite each other in the axial direction when assembled and define a common receiving area which, by positive locking with the support section (151), defines an axial position of the retaining element (105). [10] Air heater (102) according to any one of claims 5 to 9, wherein Both the first housing element (108) and the second housing element (118) each have a substantially square or rectangular cross-sectional profile in a plane perpendicular to the longitudinal axis; wherein each of the support sections contacts and supports one of the four corners of the cross-sectional profile of the first housing element (108) and / or the second housing element (118). [11] Air heater (1) according to one of claims 5 to 10, wherein the assembly of the mounting elements (105) has an overall X-shaped structure in the direction of view along the longitudinal axis (L). [12] Air heater (1) according to any one of claims 1 to 11, wherein the combustion air blower housing component (107) is a die-cast part, preferably made of aluminum or an alloy thereof; and / or Both the first housing element (108) and the second housing element (118) are each one-piece molded plastic parts. [13] Method for assembling an air heater (1) according to any one of claims 1 to 12, comprising: Providing the assembly (11), the heat exchanger element (13) thermally interacting with it, the combustion air blower module (6, 106) and the hot air blower; Positioning the first housing element (8, 108) and the second housing element (18, 118) in opposite axial directions parallel to the longitudinal axis (L); Locking the first housing element (8, 108) and the second housing element (18, 118) together or with the combustion air blower module (6, 106). [14] Air heater (102), in particular a fuel-based air heater, for a vehicle, comprising: a component assembly (11) for generating heat; a heat exchanger element (13) that thermally interacts with the assembly (11); a combustion air blower module (106) comprising a combustion air blower operated by a motor (M), which is configured to draw in combustion air during operation and to supply the assembly (11) for generating heat with the combustion air, wherein the air heater (102) defines a longitudinal axis (L) extending parallel to a drive shaft (31) of the motor (M); the motor (M) to drive the combustion air blower; an electronic control unit (ECU) for controlling the engine; a bracket (140) for holding the control unit (ECU); characterized by , that the control unit (ECU) is provided with at least one locking element (220) which interacts with a corresponding carrier element (141) of the holder (140) in a locking connection (300) to attach the control unit (ECU) to the holder. [15] Air heater (1) according to claim 14, wherein the bracket (140) comprises two of the support elements (141) which extend from the housing component (107) parallel to the longitudinal axis (L); and the control unit (ECU) is provided with at least two locking elements (220), preferably four locking elements (220), one of which interacts with one of the carrier elements (141), preferably two interacting with one of the carrier elements (141). [16] Air heater (1) according to claim 15, wherein the two support elements (141) are designed as angle brackets. [17] Air heater (1) according to one of claims 15 to 16, wherein the combustion air blower module (106) comprises a one-piece combustion air blower housing component (107) which at least partially forms the combustion air blower; and the corresponding support element (141) extends from the housing component (107) parallel to the longitudinal axis (L). [18] Air heater (1) according to one of claims 15 to 17, wherein the two support elements are formed integrally with the combustion air blower housing component (107). [19] Air heater (1) according to one of claims 15 to 18, wherein the locking elements (220) in the respective locking connection (300) extend perpendicular to the respective support element (141) and parallel to each other to allow the control unit (ECU) to be clipped onto the holder (140) during its mounting on the holder in a radially inward movement towards the longitudinal axis. [20] Air heater (1) according to claim 19, wherein the control unit (ECU) has a control unit housing (210) from which the locking elements (220) extend and with which they are integrally formed. [21] Air heater (1) according to claim 20, wherein the control unit housing (210) has a support projection (215) with which it rests on the support element (141), wherein in the clipped-on state of the control unit (ECU) the support projection (215) and a locking lug (224) fix the support element (141) between them in the direction perpendicular to the longitudinal axis (L). [22] Air heater (1) according to claim 20 or 21, wherein in the control unit housing (210) of the control unit (ECU) a first connector basket (264) with exposed circuit board contacts (262) is formed therein; and a second connector basket (240) with exposed motor contacts (250) is formed on a housing of the motor (M); wherein the second connector basket (240) is arranged to be received in the first connector basket (264) in order to establish an electrical connection between the circuit board contacts (262) and the motor contacts (250). [23] Air heater (1) according to claim 22, wherein, when the motor (M) is fixed to the combustion air blower housing component (107) and the control unit (ECU) is clipped onto the holder (140), the second connector basket (240) is received in the first connector basket (264) and, by the resulting positive locking, the control unit (ECU) is fixed, in particular, also in a circumferential direction around the longitudinal axis (L). [24] Air heater (1) according to claim 22 or 23, wherein a circumferential seal (242) is provided inside the first connector basket (264) or outside the second connector basket (240), so that a space with the mutually contacting circuit board contacts (262) and motor contacts (250) is sealed inside the two connector baskets (264, 240). [25] Air heater (1) according to claim 22 or 23, wherein the circuit board contacts (262) are mounted directly on a control board (260) of the control unit (ECU) and extend into the first connector basket (264) provided as a recess in the control unit housing (210).

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