EP3417227B1 - Heat exchanger, in particular water-air heat exchanger or oil-water heat exchanger - Google Patents

Description

The invention relates to a heat exchanger, in particular a water-air heat exchanger or an oil-water heat exchanger according to claim 1, and a method for producing a heat exchanger, in particular a water-air heat exchanger or an oil-water heat exchanger according to claim 6.

For example EP 2 466 241 A1 describes an oil-water heat exchanger with several pan elements stacked on top of one another and soldered together. Such oil-water heat exchangers are usually integrated into the cooling circuit of internal combustion engines and can be used, for example, to cool the engine oil.

Another oil-water heat exchanger is in US 2015/0176913 A1 shown.

In a particular embodiment, an electric heater is proposed there in an interior space of the heat exchanger in order to heat one of the interacting fluids of the heat exchanger.

DE 10 2013 010 907 A1 shows an electrical heating device for heating a first medium and a second medium according to the preamble of claim 1, comprising at least one pipe carrying the second medium, a heat exchanger which is in thermally conductive contact with the at least one pipe and which carries the first medium, and a Layer heating element that at least partially covers the surface of the at least one tube.

FR 2 966 580 A1 shows a heat exchanger which has a collector box for receiving a coolant and a radiator in which the coolant is circulated. The collector box contains an electrical heating element, for example an electric immersion heater, which is provided with an active part which extends into an internal volume defined by the collector box.

In principle, it is felt to be disadvantageous in the known oil-water heat exchangers that they can either not be preheated at all or can only be preheated in a comparatively complex and ineffective manner. In particular, the reduction of pollutants that arise when the engine oil is not at operating temperature is seen as in need of improvement.

Furthermore, with regard to the state of the art, in principle WO 2013/186106 A1 and WO 2013/030048 A1 referenced. There, heaters are described that have an electrical heating layer that heats up when an electrical voltage is applied (or when a current flows).

Furthermore, regarding the state of the art, please refer to DE 10 2011 006 248 A1 referenced. A household refrigerator with a heating device is described there. The heating device is produced as a layer heater by painting and applied to a surface of an evaporator of the household refrigerator. Specifically, the stratified heating is according to DE 10 2011 006 248 A1 Directly applied over a surface of the evaporator and hardly thermally insulating in order to impair the functionality of the evaporator as little as possible. However, it is considered to be disadvantageous that the production according to this prior art is comparatively complex and appears to be tailored to a very special application.
It is the object of the invention to propose a heat exchanger which enables a fluid flowing through the heat exchanger to be heated in a simple and effective manner.

This object is achieved by the features of claim 1.

In particular, the object is achieved by a heat exchanger, in particular water-air heat exchanger or oil-water heat exchanger, comprising at least one first fluid channel for guiding a first fluid (e.g. oil from an oil-water heat exchanger or water from a water-air heat exchanger ), as well as at least one second fluid channel for guiding a second fluid (e.g. water of the oil-water heat exchanger or air of the water-air heat exchanger), the at least one first fluid channel being connected to a fluid receiving volume (in particular the outlet side), the fluid receiving volume is equipped with an electrical heating coating, wherein the fluid receiving volume is provided by a separate module, wherein the separate module can be or is attached to the remaining components of the heat exchanger. The heat exchanger can generally be a liquid-liquid heat exchanger or a liquid-gas heat exchanger or a gas-gas heat exchanger.

A core idea of the invention is that of the per se, for example WO 2013/186106 A1 or WO 2013/030048 A1 known electrical heating coatings to apply to a fluid receiving volume which is connected to at least one of the fluid channels. As a result (in particular if the electrical heating coating is arranged on the outlet side), a fluid to be heated with the heat exchanger can effectively be additionally heated or the temperature of a heating fluid can be increased further (in particular if the electrical heating coating is connected on the inlet side to a fluid channel of the heating fluid). Overall, a fluid can be effectively heated, for example an oil of an oil-water heat exchanger for an internal combustion engine of a motor vehicle can be heated. The heat exchanger can have several first fluid channels and / or several second fluid channels. For example, the fluid receiving volume is a volume of the heat exchanger before (or after) the fluid is distributed to a plurality of individual fluid channels (that is to say, for example, a fluid collecting device or fluid distributing device). The first fluid can be oil or water. The second fluid can be water or air. In general, the first and / or second fluid can be liquid or gaseous.

In a specific embodiment, the fluid receiving volume is defined by a fluid receiving container, in particular an oil receiving container. Such a fluid receiving container, in particular an oil receiving container, is preferably connected on the outlet side to one or more fluid channels through which oil preferably flows. As a result, additional heating can take place in an effective manner (for example after the engine of a motor vehicle has been started).

In a specific embodiment, the fluid receiving volume can be defined by a connection pipe, in particular an outlet pipe, preferably an oil-water heat exchanger. This is a simple way (under Use of existing structures) allows the fluid, in particular oil, to be heated up.

In one embodiment, a turbulator can be provided. This is preferably provided in the vicinity of an electrical heating coating (ie in particular not further than 5 cm, in particular 2 cm away). For example, the turbulator can be arranged inside the outlet pipe (provided with an electrical heating coating).

In principle, the electrical heating coating can be arranged on an outer wall of the fluid receiving volume (for example outlet pipe) or on an inner wall of the fluid receiving volume (for example outlet pipe). If a turbulator is provided, it can optionally also be provided with an electrical heating coating itself.

The fluid receiving volume is provided by a separate module, the separate module being attachable or being attached to the other components of the heat exchanger. According to the invention, a separate fluid receiving volume is proposed so that existing heat exchangers (in particular oil-water heat exchangers) can be further improved by a simple upgrade. On the other hand, the modular design of the fluid intake volume also has the advantage that manufacturing costs can possibly be reduced, for example by using the same fluid intake module for different types and / or sizes of heat exchangers.

The heating coating is particularly preferably designed for operation in the low-voltage range, preferably for 12 volts, 24 volts or 48 volts. Appropriate electrical and / or electronic components of the oil-water heat exchanger are then preferably also designed for such a low-voltage range (12 volts, 24 volts or 48 volts). Particularly when used in the low-voltage range, effective preheating can be achieved with simple means in a synergistic manner. "Low-voltage range" should preferably be understood to mean an operating voltage of less than 100 V, in particular less than 60 V (direct current).

In one embodiment, the heating coating is applied indirectly, in particular via an insulation layer, to or in the fluid receiving volume. Such an insulation layer can be formed, for example, by an adhesion promoter layer or attached to the oil-water heat exchanger via such a layer. A polymer material or a ceramic material (for example Al ₂ O ₃ ) can preferably be used for the insulation layer. Preferably, however, the insulating layer is provided by passivation, in particular oxidizing, in particular anodizing (of aluminum or an aluminum alloy), preferably a surface, for example an outer and / or inner surface, of the fluid receiving volume. Overall, simple yet adequate electrical insulation is provided (especially in low-voltage applications). Alternatively, the heating coating can even be applied directly to or in the fluid receiving volume (for example in low-voltage applications and / or if the substrate is not or only poorly electrically conductive). The heating coating and / or insulation layer is preferably applied over the entire surface of the fluid receiving volume. Furthermore, the heating coating and / or the insulation layer can have an (at least essentially) constant layer thickness. The heating coating and / or the insulation layer can per se be designed to be dimensionally unstable (or not self-supporting). A substrate can be dispensed with, so that the heating coating (and an optional insulation layer) may be formed free of a substrate. A possibly necessary carrying and / or support structure can be provided by the fluid receiving volume (or a wall of the same). In principle, the heating coating can be materially connected to a surface, in particular an outer and / or inner surface, of the fluid receiving volume.

In an alternative embodiment, the heating coating is designed as a continuous (in particular unstructured and / or uninterrupted) layer.

The heating coating can generally have at least one section within which there are no interruptions in the heating coating in two mutually perpendicular directions over a distance of at least 1 cm, preferably at least 2 cm, even more preferably at least 4 cm. For example, the heating coating can comprise at least one rectangular section with a length and a width of at least 1 cm, preferably at least 2 cm, even more preferably at least 4 cm, within which there are no interruptions or possibly other structures in the heating coating. An “interruption” within the heating coating is to be understood as a section through which no current can flow, for example because this section remains (completely) free of material and / or is (at least partially) filled with an insulator. The heating coating can be (thermally) sprayed on (regardless of whether it is unstructured or structured, in the final state). In this context it has surprisingly been found that even such a simply configured heating coating can bring about sufficient heating of the oil.

In a further alternative embodiment, the heating coating is designed as a structured layer. The heating coating is preferably structured by a masking process (preferably using silicone, which can be embossed). Such known masking methods allow a satisfactory structuring and are less complex than, for example, laser methods for structuring, which are used in the high-voltage range. Overall, therefore, the advantages of a masking process are used in a synergistic manner with regard to the present heating coating.

The insulating layer described above can have a thickness of at least 50 μm, preferably at least 200 μm and / or at most 1000 μm, preferably at most 500 μm.

The heating coating preferably has a height (thickness) of at least 5 μm, preferably at least 10 μm and / or at most 1 mm, preferably at most 500 μm, even more preferably at most 30 μm, even more preferably at most 20 μm. A conductor path defined by the heating coating can be at least 1 mm, preferably at least 3 mm, even more preferably at least 5 mm, even more preferably at least 10 mm, more preferably at least 30 mm wide. “Width” should be understood to mean the extension of the conductor track perpendicular to its longitudinal extension (which usually also defines the direction of the current flow).

In an alternative embodiment, a protective cover, for example a silicone protective layer, is attached over the heating coating. Alternatively, however, the heating coating can also define an outside or inside of the fluid receiving volume (in an embodiment that is particularly easy to manufacture).

In a specific embodiment, the oil-water heat exchanger has a plurality of modules, in particular tub elements, which further preferably, as in FIG EP 2 466 241 A1 described, can be formed. In principle, the oil-water heat exchanger (apart from the fluid holding volume according to the invention) as in EP 2 466 241 A1 or US 2015/0176913 A1 described, be formed. The disclosure of these documents is hereby explicitly incorporated by reference. If several modules are provided, at least one heating coating can be arranged between two modules. If the oil-water heat exchanger comprises several pan elements, at least one heating coating can optionally be arranged (applied) between two of these pan elements (on one of the pan elements). As a result, the preheating (additional heating) can be further improved with simple means. In general, an additional heating coating can be applied to further surfaces of the heat exchanger.

The object is also achieved by a method for producing a heat exchanger, in particular a water-air heat exchanger or an oil-water heat exchanger, in particular of the type described above, according to claim 6, comprising the provision of at least one first fluid channel for guiding a first fluid (e.g. an oil of the oil-water heat exchanger or water of the water-air heat exchanger) and at least one second fluid channel for guiding a second fluid (e.g. water of the oil-water heat exchanger or air of the water-air heat exchanger), the at least one first fluid channel is connected to a fluid receiving volume, in particular on the outlet side, the fluid receiving volume being equipped with an electrical heating coating (or a surface of the fluid receiving volume being coated directly or indirectly with the electrical heating coating). Between the two mentioned steps, the application of an insulating layer to a surface of the fluid receiving volume can be carried out (or a surface of the fluid receiving volume can be coated directly or indirectly with the insulating layer), for example by passivation (oxidation, in particular anodizing) of a substrate, for example a heat exchanger housing. If necessary, the electrical heating coating can be sprayed on (thermally). Insofar as features are described further above (in connection with the heat exchanger) which are at least also related to the production of the oil-water heat exchanger, these method features are also proposed as preferred embodiments of the method.

The above-mentioned object is also achieved by using a heat exchanger of the type described above or produced according to the type described above, as a water-air heat exchanger or as an oil-water heat exchanger, in particular for the internal combustion engine of a motor vehicle.

Further embodiments emerge from the subclaims.

In general, the insulating layer can be a ceramic material or a polymer material or consist of such a material, Al ₂ O _3, for example, being considered as the ceramic material.

The heating layer can be applied, for example, in a plasma coating process, in particular plasma spraying, or in a screen printing process, or as a resistance paste, in particular on the insulating layer. In the plasma coating process, for example, an electrically conductive layer can first be applied, in particular to the insulating layer. Areas can then be cut out of the electrically conductive layer so that one or more conductor tracks remain. However, a masking technique is preferably used. The conductor tracks can then form the heating resistor or several heating resistors. As an alternative to a masking technique, the areas mentioned can be cut out of the conductive layer, for example by means of a laser. The heating coating can for example be a metal layer and possibly contain nickel and / or chromium or consist of these materials. For example 70-90% nickel and 10-30% chromium can be used, with a ratio of 80% nickel and 20% chromium being considered to be suitable.

The heating coating can, for example, occupy an area of at least 5 cm ² , preferably at least 10 cm ² and / or at most 200 cm ² , preferably at most 100 cm ² . The oil-water heat exchanger can have a total volume of preferably at least 200 cm ³ , even more preferably at least 500 cm ³ , even more preferably at least 800 cm ³ and / or at most 5000 cm ³ , preferably at most 2000 cm ³ . For example, the oil-water heat exchanger can be 15-25 cm long and / or 8-12 cm wide and / or 3-7 cm high (thick).

The oil-water heat exchanger preferably has one or more first fluid channels for guiding the oil and one or more second fluid channels for guiding the water.

A bimetal switch, possibly with two redundant switch devices, can be provided for controlling, in particular regulating, the electrical heating coating.

Only those embodiments that fall within the scope of the claims are considered to be embodiments of the invention. All other embodiments are considered to be examples that are useful for understanding the invention.

Fig. 1

eine schematische Seitenansicht eines Öl-Wasser-Wärmetauschers gemäß einer ersten Ausführungsform der Erfindung;

Fig. 2

einen Öl-Wasser-Wärmetauscher gemäß einer alternativen Ausführungsform der Erfindung; und

Fig. 3

einen Wasser-Luft-Wärmetauscher gemäß einer Ausführungsform der Erfindung.

The invention is described below on the basis of exemplary embodiments which are explained in more detail using the figures. Here show:

Fig. 1

a schematic side view of an oil-water heat exchanger according to a first embodiment of the invention;

Fig. 2

an oil-water heat exchanger according to an alternative embodiment of the invention; and

Fig. 3

a water-air heat exchanger according to an embodiment of the invention.

In the following description, the same reference numbers are used for parts that are the same and have the same effect.

Fig. 1 shows a schematic view of an oil-water heat exchanger (as shown in detail, for example, in EP 2 466 241 A1 is described) with several (soldered) pan elements 10, a cover 19, an inlet pipe 11 and an outlet pipe 12 for the oil flowing in the heat exchanger. An electrical heating coating 13 is applied at least to the outlet pipe 12 (possibly in the inlet pipe 11).

In the alternative embodiment according to Fig. 2 an electrical heating coating 13 is arranged on a fluid receiving container 14. The fluid receiving container 14 has a (significantly) enlarged diameter compared to the outlet pipe 12 according to FIG Figure 1 or a fluid receiving container outlet pipe 15 so that the fluid (oil) can be stored in the fluid receiving container 14. The fluid receiving container 14 can be, for example, a cuboid or cylindrical body. In the specific embodiment according to Fig. 2 the fluid receiving container 14 is provided as an additional module which is connected to an outlet 20 of a heat exchanger main body 21. It would also be conceivable to design the fluid receiving container 14 as an integral part of the oil-water heat exchanger, so that the outlet 20 can be omitted.

In Fig. 3 A water-air heat exchanger is shown, which has a collecting box 16 and heat exchanger tubes 17, with water for heating (or cooling) a gas (in particular air) flowing past the heat exchanger tubes 17 being provided through both the collecting container 16 and the heat exchanger tubes 17. There is an electrical heating coating 13 on the collecting box 16. A plurality of heat exchanger tubes 17 are connected to the collecting box 16 via connection pieces 18. At least 3, or at least 5, or at least 20 heat exchanger tubes 17 can be connected to the same collecting box 16. The water can enter via an inlet (inlet pipe 11) and exit via an outlet (outlet pipe 12).

Reference number

10

Tub element

11

Inlet pipe

12th

Outlet pipe

13th

electrical heating coating

14th

Fluid holding container

15th

Fluid receiver outlet tube

16

Collection box

17th

Heat exchanger tube

18th

Connection device

19th

cover

20th

Outlet

21

Heat exchanger main body

Claims (7)

1. Heat exchanger, in particular water-air heat exchanger or oil-water heat exchanger, comprising at least one first fluid channel for conducting a first fluid, and at least one second fluid channel for conducting a second fluid,
   wherein the at least one first fluid channel is connected to a fluid-receiving volume, in particular at an outlet side, wherein the fluid-receiving volume is equipped with an electric heating coating (13),
   characterized in that
   the fluid-receiving volume is provided by a separate module, wherein the separate module is fastenable or fastened to the other constituent parts of the heat exchanger.
2. Heat exchanger according to Claim 1,
   characterized in that
   the fluid-receiving volume is defined by a fluid-receiving vessel (14), in particular oil-receiving vessel.
3. Heat exchanger according to Claim 1 or 2, characterized in that
   the fluid-receiving volume is defined by a connection pipe, in particular outlet pipe (12).
4. Heat exchanger according to any of the preceding claims,
   characterized in that
   a turbulator is provided preferably in the vicinity of an electric heating coating (13).
5. Heat exchanger according to any of the preceding claims,
   characterized in that
   the electric heating coating (13) is designed for operation in the low-voltage range, preferably for 12 volts, 24 volts or 48 volts.
6. Method for producing a heat exchanger, in particular a water-air heat exchanger or an oil-water heat exchanger, comprising the steps:

   - providing at least one first fluid channel for conducting a first fluid, and a second fluid channel for conducting a second fluid, wherein the at least one first fluid channel is connected to a fluid-receiving volume, in particular at an outlet side, wherein the fluid-receiving volume is equipped with an electric heating coating (13), wherein the fluid-receiving volume is provided by a separate module, wherein the separate module is fastenable or fastened to the other constituent parts of the heat exchanger.
7. Use of a heat exchanger according to any of Claims 1 to 5, preferably produced according to Claim 6, as a water-air heat exchanger or as an oil-water heat exchanger, in particular for the internal combustion engine of a motor vehicle.

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