EP1967397A1 - Electric heating assembly, in particular for a motor vehicle - Google Patents

Abstract

The arrangement has at least two control element-positive temperature coefficient element groups connected together via a first bus bar (7) connected to a pole of a power supply by at least one conductor (8,10). The conductor runs in parallel with a separate conductor connected directly or via a second bus bar separate from the first bus bar to at least one further control element-positive temperature coefficient element group.

Description

The invention relates to an electrical heating arrangement with PTC elements, in particular for a motor vehicle.

An arrangement of strip or cuboid PTC elements between contact plates and / or corrugated ribs, via which the electrical contacting takes place, is known. In this case, the air to be heated essentially absorbs the heat emitted by the PTC elements from the corrugated fins provided for the enlargement of the heat transfer surface. The PTC elements may be plastic or ceramic elements.

An example of such an embodiment is shown in FIG EP 1 522 439 A1 disclosed. Here, the arranged between the contact plates PTC elements and arranged on the outside of the contact plates corrugated fins are held in an electrically insulating plastic frame.

The electrical contacting of the contact sheets can be effected in that the contact plates protrude laterally from the frame and a plug connection is provided, wherein the frame can be designed accordingly. However, the contact plates can also be within the frame Be connected contact rails, which are contacted from the outside, or an electrical conductor is inserted directly into the frame and connected to the contact rails or contact plates.

A control of individual heating strands can be done by means of an electronic circuit. This circuit may be integrated, as in the in Fig. 3 to illustrate a conventional structure of a heating device shown, but for reasons of heat it is usually arranged as far as possible from the heating area.

From the DE 199 05 074 C1 is an electric heater with a plurality of selectively acted upon by an electronic circuit groups of PTC heating elements for a motor vehicle known. Here, at least two of the groups have different nominal powers. The power is supplied from a voltage source, all groups are connected via a common collective distribution line at both the plus and the negative terminal to the power supply. The control elements, which enable switching on and off of the individual branches, and the PTC heating elements are arranged in the respective branches connected in parallel with one another. Such a heater leaves nothing to be desired.

It is an object of the invention to provide an improved electrical heating arrangement with electrical heating elements, in particular PTC elements available.

This object is achieved by an electrical heating arrangement with the features of claim 1. Advantageous embodiments are the subject of the dependent claims.

According to the invention, an electrical heating arrangement is provided, in particular for a motor vehicle, having a heat transfer area for transferring the heat generated to a fluid flowing through the electric heater arrangement, the heat transfer area having a plurality of PTC elements electrically interconnected in a plurality of groups, and each of the groups of a rule element is controllable independently of other groups, and the individual rule element PTC element groups are connected to a common power supply. The heat transfer area forms the core area of a heater of the heating arrangement. In this case, at least two control element PTC element groups are interconnected via a first bus bar, which is connected via at least one current conductor to one pole of the power supply, wherein the current conductor at least partially separated running from at least one further, parallel to the first conductor connected, second Conductor is formed, which is connected directly or via a further bus bar, which is formed separately from the first bus bar, with at least one further control element PTC element group. By dividing the current into several branches, which are connected in parallel, the current intensity in the individual conductors and busbars can be reduced.

Preferably, in each case at least two, in particular exactly two control element PTC element groups are connected to one another via a busbar. Furthermore, the busbars are preferably each connected via a separately formed current conductor with a pole, in particular preferably the negative pole, the power supply.

In each of the conductors or arranged in series with each of the conductors is preferably provided a separate fuse, which is independent of the one or other of the other fuses. This allows separate protection of individual heating areas of the heater, the example. Different Zones are assigned to the air conditioning of the vehicle interior.

The fuses are preferably outside the heat transfer region of the heater assembly, in particular outside of a frame, which is traversed by the vehicle interior air to be supplied, arranged.

Each of the current conductors is preferably formed by cables with a cross-sectional area of 5 to 8 mm ² , more preferably of about 6 mm ² +/- 1 mm ² . The current conductors are particularly preferably formed by individually sheathed, separately formed cable. These, in contrast to conventional cables, over which the entire current flows, much thinner auslegbaren cables can be bent easily and therefore easier to assemble.

Alternatively, for example, multi-core flat cables can be used. These can be flexibly adapted to the available installation space, at least in one plane, or even lead through narrow gaps, so that they can be laid more easily in relation to the conventionally used cables with a core and the associated larger diameter.

Each control element of a control element PTC element group is preferably controllable via a common BUS system. The control elements are, for example, transistors.

Each of the control element PTC element group of the heating arrangement preferably has at least one plate-shaped PTC element. This PTC element can be both a ceramic and a plastic PTC element.

Particularly preferably, a plurality of PTC elements is provided in at least one control element PTC element group, wherein the PTC elements are preferably arranged in a row and possibly spaced from each other between contact plates. The function of the contact plates can also be fulfilled directly by corrugated ribs with appropriate design.

The electrical heating arrangement preferably has an insulating housing or a frame, on the outside of which at least part of a plug connection for electrical contacting is provided, wherein the plug connection provides a connection for connecting at least two separately formed but parallelly connected current branches. However, it is also possible to provide a plurality of plug connections, so that, for example, only one current conductor is connected in each case with the aid of a plug connection. In general, connecting several smaller cable strands is easier than connecting a thick cable, which is severely limited in terms of its flexibility.

The frame is preferably made of polyamide, more preferably PA66, and is injection molded. It can be formed with a corresponding embodiment, but in particular also in several parts, wherein the individual parts can be connected to each other in a known manner, for example by means Verclipsens or screwing. This can be done in the frame by connecting the parts at the same time a fixation of the contact plate PTC elements corrugated fin arrangement.

Heating arrangements according to the invention can be provided both as a heater in conjunction with a conventional air conditioner or a conventional heater and in isolation.

Fig. 1

eine schematische Darstellung einer erfindungsgemäßen Heizungsanordnung,

Fig. 2

eine schematische, ausschnittsweise Darstellung des Heizbereichs der Heizungsanordnung von Fig. 1, und

Fig. 3

eine schematische Darstellung einer herkömmlichen Heizungsanordnung.

In the following the invention with reference to an embodiment with reference to the drawings will be explained in detail. In the drawing show:

Fig. 1

a schematic representation of a heating arrangement according to the invention,

Fig. 2

a schematic, partial view of the heating of the heating arrangement of Fig. 1 , and

Fig. 3

a schematic representation of a conventional heating arrangement.

A two-zone heater assembly 1 according to the embodiment serves as a heater in an automotive air conditioner, being arranged in the air flow direction according to a conventional heater. The heating assembly 1 has a frame 2 made of plastic, in this case PA66, which is injection-molded. In the frame, a plurality of plate-shaped plastic PTC elements 3 between contact plates 4 and disposed therebetween corrugated fins are arranged, as in partial manner in Fig. 2 shown. In Fig. 1 are the PTC elements 3 schematically indicated as resistors. The PTC elements 3, the contact plates 4 and the corrugated fins form the core of the auxiliary heater of the heating arrangement 1, which is flowed through by the vehicle interior air to be supplied.

In each case one of the contact plates 4 of a pair of contact plates between which PTC elements 3 are arranged protrudes on one side beyond the air-flow area of the frame 2 and is electrically contacted. These contact plates 4 are connected to the positive pole "+" of the power source (not shown in detail) via a common conductor and one in the frame 2 trained plug plugged connector (not shown), wherein within the frame 2, a continuous, common bus bar 5 is provided, which is guided by the corresponding contact plates 4 to the edge of the frame 2 and ends in the socket.

The other of the contact plates 4 of a contact plate pair is presently connected on the other side of the frame 2 via an electrically conductive intermediate piece, each with a regulator 6, which is arranged in a presently not air-flow area of the frame. For cooling, however, an air flow can also be provided in this area. The controller 6 are controlled by means of a bus system, indicated in the drawing with "bus".

The controller 6 are in turn connected to busbars 7, wherein in the present case two controllers 6, which are assigned in the present case a heating zone, are connected in series with a busbar 7. The busbar 7 is contacted centrally with a current conductor 8, which extends up to an integrated integrated socket 9. The conductor 8 may in the case of a corresponding T- or L-shaped configuration of the busbar 7, so that the same extends to the socket 9, also omitted.

In the socket 9, a plug 10 can be inserted, which forms an electrical contact of each of the current conductors 8, each with a continuing current conductor 10. In the present case, each of the continuing current conductors 10 in each case contains a fuse 11 in order to protect the corresponding PTC elements 3 from excessive current flow which would result in overheating of the PTC elements 3. In the present case, each of the current conductors 10 is connected to the negative pole "-" of the current source, ie the current conductors 10 are connected in parallel with one another. Each of the secondary current conductors 10 in the present case has an electrically conductive cross section of approximately 6 mm ² . The individual conductors 10 may each be separated from each other be surrounded by an insulator, however, for example, a parallel arrangement of the same possible, so that a flat cable of low height results with parallel juxtaposed conductors.

The function of the heater assembly 1 is the following: Between the sockets formed on the frame 2, the vehicle electrical system voltage is applied, wherein - if there is no heating demand - all controller 6 interrupt the circuit, so that no current flows. From one of the zones - from a passenger by hand by means of a corresponding actuator or automatically based on a comparison of a temperature setpoint with a Temperaturistwert and falling below the temperature setpoint by a predetermined amount - a heating request to the corresponding controller 6 via the bus system. The regulator 6 reduces its resistance so that current can flow through the corresponding branch, while the other branches connected in parallel are blocked by the other regulators 6. The current flows to the first contact plate 4, through the PTC elements 3, which are arranged between the first and second contact plate 4, and the second contact plate 4. As a result of the current flow through the PTC elements 3, which consists of a material with a positive temperature coefficient exist, the material heats up. The heat is released to the outside to the air flowing through the heater, which is supplied to the vehicle interior. Due to the material heating, however, the resistance of the PTC elements 3 increases, so that the current flow as a function of the temperature in the PTC elements 3 is set to a specific value.

If more heat is needed in the corresponding zone, then the second regulator 6, which is assigned to this zone, is regulated in such a way that current flows through the branch associated with it, so that the number of heated PTC elements 3 is increased.

If the total current flowing through the two branches rises above an upper limit, for example due to a short circuit in the heater, the fuse of the corresponding conductor 10 burns and the current flow is completely interrupted.

Regardless of the first zone just described, the control of the second zone takes place, so that it will not be discussed in more detail below.

Alternatively to the representation of Fig. 1 The connection of the individual PTC elements can also be such that a different number of heating stages and / or more or fewer zones are possible. However, the interconnection is essentially independent of the subdivided configuration of the continuing current conductors 10 and of the busbars 7.

Furthermore, instead of two current conductors 10, more, for example four current conductors, may also be provided. Accordingly, four busbars are then provided in the frame.

Within the frame 2, not necessarily two controllers 6 must be connected to a busbar 7. The number of regulators 6 (and thus of the groups of jointly controlled PTC elements), which are supplied with current via a common busbar 7, can be larger or smaller. The ideal case, however, is that an electrical contact is provided at each end of a busbar 7.

According to a variant of the embodiment, the busbars are formed divided on both sides of the contact plates. The same applies to the current conductors, so that two parallel circuits are formed, whereby the conductor diameter of all conductors reduced and Flat cable with juxtaposed conductors or separately formed cables can be used.

Claims (10)

An electric heater assembly (1), particularly for a motor vehicle, having a heat transfer area for transferring the generated heat to a fluid passing through the electrical heater assembly, the heat transfer area having a plurality of PTC elements electrically interconnected in a plurality of groups, and each of the groups Regulating element (6) is independent of other groups controllable, and the individual rule element PTC Elemerit groups with a common power supply (+, -) are connected, characterized in that at least two control element PTC element groups via a first busbar (7) are interconnected, which is connected via at least one conductor (8, 10) to one pole (-) of the power supply, wherein the conductor (8, 10) at least partially separated from at least one further, parallel to the first conductor ( 8, 10), the second current conductor (8, 10) is formed, which is connected directly or via a further bus bar (7), which is formed separately from the first bus bar (7), with at least one further control element PTC element group. Heating arrangement according to claim 1, characterized in that the at least two, in particular exactly two control element PTC Eiement-Gmppen via a busbar (7) connected to each other are, and the busbars (7) each have a separately formed conductor (8, 10) connected to a pole (-) of the power supply. Heating arrangement according to claim 1 or 2, characterized in that in each of the conductors (10) or arranged in series to each of the conductors (8) has its own fuse (11) is provided, which is independent of the or the other fuses (11) , Heating arrangement according to claim 3, characterized in that the fuses (11) outside the heat transfer region of the heating arrangement (1), in particular outside a frame (2) are arranged, which can be flowed through by the vehicle interior air to be supplied. Heating arrangement according to one of the preceding claims, characterized in that each of the current conductors (10) by cables with a cross-sectional area of 5 to 8 mm ₂ , in particular of about 6 mm ² +/- 1 mm ² , is formed. Heating arrangement according to one of the preceding claims, characterized in that each control element (6) of a control element PTC element group via a common bus system (bus) is controllable. Heating arrangement according to one of the preceding claims, characterized in that each of the control element PTC element group of the heating arrangement (1) has at least one plate-shaped PTC element (3). Heating arrangement according to claim 7, characterized in that at least one control element PTC element groups, a plurality of PTC elements (3) is provided. Heating arrangement according to one of the preceding claims, characterized in that the electrical heating arrangement (1) has an insulating housing or a frame (2), on the outside of which at least part of a plug connection is provided for electrical contacting, wherein the plug connection is a connection for connection at least two separately trained, but connected in parallel current branches provides. Heating arrangement according to one of the preceding claims, characterized in that the current conductors (10) are formed by individually sheathed, separately formed cable.

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