WO2010099946A2

WO2010099946A2 - Heat exchanger for cooling oil

Info

Publication number: WO2010099946A2
Application number: PCT/EP2010/001312
Authority: WO
Inventors: Thomas Weimer
Original assignee: Makatec Gmbh
Priority date: 2009-03-04
Filing date: 2010-03-03
Publication date: 2010-09-10
Also published as: EP2404132A2; DE202009003521U1; WO2010099946A3

Abstract

The present invention relates to a device for transferring heat between engine oil and cooling water in vehicles, in which flow channels of the engine oil and of the cooling water adjacent to one another are formed by superposing thin, elastic foils while ensuring specific distances, wherein the foils serve as heat transfer surfaces between the respective flow channels, wherein at the same time a diffusion of engine oil and water between the respective flow channels is prevented, and wherein the foils are designed to be resistant to a predetermined, defined maximum temperature and for a specifically predetermined operating time. Further, the present invention relates to a respective method.

Description

Heat exchanger for oil cooling

Summary

This invention relates to easily mounted heat exchanger with low weight, especially for oil cooling in transport of all kinds.

Field of the invention

The present invention is in the field of heat transfer between fluids. The present invention relates to easily assembled heat exchanger cartridges made of films, preferably from polymer materials, but also from other material combinations, for use in vehicles.

State of the art

The thermal management of combustion engines in vehicles has now reached a high level of complexity. While in the first vehicles only a sufficient engine cooling was to ensure through simple air cooling, the engine is cooled in modern vehicles with cooling water. In order to cool modern engines in hard-to-reach places is now often used the engine oil for cooling, which then has to be recooled with cooling water. All devices for cooling vehicles now have a significant volume and weight percentage in the vehicle. As a simplification, it can be said for the traffic sector that predominantly materials with good thermal conductivity are used for the construction of heat exchangers or heat transfer systems. These are mainly copper, aluminum and stainless steel.

An object of the invention is to provide in the vehicle a lightweight and compact heat exchanger for heat transfer between engine oil and cooling water, which is characterized in particular by corrosion resistance, a compact design and a significantly lower weight compared to conventional heat exchangers.

Summary of the invention

For this purpose, the invention provides a device for heat transfer or exchange of heat between fluids, are used in the thin, elastic films as heat transfer surfaces between the flow channels of the fluids.

According to claim 1, there is provided an apparatus for transferring heat between engine oil and cooling water in vehicles in which mutually adjacent flow channels of the engine oil and the cooling water are formed by superimposing thin elastic sheets while maintaining specific pitches, the sheets being heat transfer surfaces serve between the respective flow channels, at the same time a diffusion of engine oil and water between the respective flow channels is prevented and the films are designed to be compared to a predetermined, defined maximum maltemperatur and to be stable for a specific predetermined operating time.

With this invention, it is also possible to compactly integrate the device in heat exchanger cartridges, which can be exchanged in a simple manner, which was previously only possible by replacing the entire heat exchanger system.

In particular, for modular construction, in various industries, this type of heat exchanger cartridges, such as. e.g. Oil pan modules of the automotive industry, see patent DE 102 18 338 Al.

The films used may contain plastics or other materials, in particular metal for improving barrier properties, i. to avoid diffusion between adjacent flow channels. Furthermore, fibers may serve as components of the films to increase mechanical strength.

The films may be made of a material selected from a group consisting of polyetheretherketone (PEEK), polytetrafluoroethane (PTFE) and polyphenylsulfone (PPSU).

Also, the heat transfer surfaces can be constructed of several film layers. For example, they may be suitably coated or coextruded films.

In order to even out fluid flows in the device and to increase flow turbulence, additional internals may be present in the flow channels delimited by the films, which are preferably designed as lattices. The grids can For example, be arranged over the entire width and length of a respective flow channel.

In a further embodiment, defined flow channels for fluid flows can be created by a surface structuring of the films.

Advantageously, a spiral structure of the flow channels, which can be achieved by a suitable winding of the films.

In addition, at least one further flow channel enclosed by a membrane with micropores can be provided, which results in the additional possibility of oil filtration with simultaneous oil cooling in a common apparatus.

The membrane can be designed for this purpose as a hollow fiber or flat membrane, and these can be arranged to produce large surface densities in the form of bundles, stacks or mats. Due to its arrangement, the membrane can provide a large surface area compared to the volume of construction occupied by the membrane.

Further, the present invention relates to a method for transferring heat between engine oil and cooling water in vehicles, wherein mutually adjacent flow channels of the engine oil and the cooling water are formed by a careful interspacing carried out succession of thin, elastic films. The films serve as heat transfer surfaces between the respective flow channels, at the same time a diffusion of engine oil and water between the respective flow channels is prevented, and the films are designed, compared to a predetermined, defined maximum temperature and to be stable for a specific specified operating time.

It is conceivable that the films are suitably coated or coextruded.

Furthermore, it is possible for means for equalizing the respective flows and for increasing flow turbulences to be provided in the respective flow channels and the means in particular to be embodied as grids.

In a further embodiment of the method according to the invention, the films are spirally wound around at least one common axis, so that substantially respective, spiral-shaped flow channels are formed.

Further advantages and embodiments of the invention will become apparent from the description and the accompanying drawings.

It is understood that the features mentioned above and those yet to be explained below can be used not only in the particular combination indicated, but also in other combinations or in isolation, without departing from the scope of the present invention.

Short description of the drawing

Figure 1 shows a schematic sectional view of an embodiment of the device according to the invention;

Figure 2 shows a schematic sectional view of another embodiment of the device according to the invention. Detailed description of the drawing

The basic structure of a suitable film heat exchanger, which can be used, for example, for oil cooling, is described in detail in EP 1 895 259 A1. For use as oil / water heat exchanger in the vehicle, the barrier property of the films used must be optimized because no water may enter the oil and vice versa. In addition, temperatures up to 150 ⁰ C must be safely overcome. Furthermore, it is desirable that the films used be stable up to an operating life of 5000 hours. The use of the high-performance polymer PEEK as a material for a film / release film to be used is therefore particularly recommendable. However, other polymers which are stable at 150 ^° C. can also be used as film materials, for example PTFE and / or PPSU. Furthermore, the films can also be metallized in order to further improve the above-mentioned barrier properties. For this purpose, it may also be advantageous to construct the films used from a plurality of layers with different materials, for example co-extruded films, the respective layers having very low diffusion values either for water or for oil, so that optimal barrier properties result in the synopsis of the resulting coextruded films , The mechanical strength of the films can also be improved, for example, by fibers in the film, for example glass, carbon, metal, and / or aramid fibers.

For bonding the end faces of the flow channels epoxy resins can be used with suitable temperature resistance. Alternatively, other temperature-resistant adhesives or sealants with suitable Resistances are used, for example, adhesives based on silicone or polyurethane casting resins.

Additional baffles may be placed between the foils, such as grids, which should have a temperature resistance of 150 ° C and should be resistant to engine oils or hot water. The grids may for example consist of fiberglass gratings with PTFE coating, carbon fibers or one of the above-mentioned high-performance polymers. Also, polyamide mesh (PA) can be used because the mesh does not require high water barrier properties. These grids increase the turbulence of fluid flows and serve as a close-meshed support material for the films, making the resulting forces on a particular film of pressure differentials very small. Furthermore, a constant thickness of the flow channel formed by the respective film boundary is ensured and thus a uniform flow through the device.

Alternatively or in addition to the use of meshes, films with a surface structure can be used which increases the surface area of the film and alters the originally flat design of conventional films. For example, during manufacture, the films can be plastically deformed such that nubs are formed as support points for resting on the respective other adjacent film. Furthermore, diagonal folds of the films are possible. Any other structure which, when laying or winding the corresponding foils, results in defined flow channels being formed, is conceivable.

The surface structures provide a defined distance between the two foils to each other and thus a defined Cross section or a defined height of the flow channel ready. The surface structures are structured such that the flow channels formed during winding are not narrowed or destroyed. The surface structures therefore preferably include the already described nubs, which rest only punctiform on the opposite film and, unlike webs during winding do not buckle and thereby narrow the channel cross section. Furthermore, the surface structure with nubs makes it possible to increase the turbulence of the flow. In this way, in contrast to a substantially laminar flow, a higher heat transfer can be achieved. Laminar flows are to be expected in particular in narrow flow channels, for example when using webs. In contrast, according to the present description, wide channels can be provided whose cross-sectional height is provided by the described surface structures and which additionally increase the turbulence of the flow.

As foils generally foils can be used, which extend essentially over the width of the device or partial sections of the width and in contrast to for example wound hoses a flow within the foil layer in two-dimensional direction (radially along the spiral winding and axially) allow and not define a substantially one-dimensional flow along the longitudinal extent of a hose or a channel formed therein.

It is conceivable that the films are not yet firmly connected to each other at the time of winding, so that they can be easily wound, since they are mutually displaceable. In this way, the different path lengths of the winding around a common axis radially outer and inner foils are taken into account. Tensions and convolutions due to tensile and compressive stresses, such as occur in hoses or other flow channels made in a flat state due to the different path lengths of the channel walls during the winding are avoided. There are thus no constrictions of the channels due to the folding or tearing due to the voltages. A firm connection of the superimposed films can take place, for example, during winding or subsequently in a suitable manner.

An extension is a use of the heat exchanger to simultaneously filter the oil during cooling. For this purpose, at least one further flow channel enclosed by a microporous membrane is additionally present, which serves to filter the oil during cooling. The basic structure of a combined oil cooler and oil filter is also described in detail in EP 1 895 259 A1. For oil filtration, the membranes should be temperature resistant up to about 150 ^° C., so that the same plastics can be used as membrane materials for the films to be used.

FIG. 1 shows a section through a film heat exchanger or exchanger with a spiral structure. The fluids 1 and 2 preferably flow countercurrently through the device. Such a heat exchanger can be produced by a simple winding of films 3, possibly in addition to grid 4 around central tubes 5 and 8. The films and possibly inserted grids are then arranged spirally. For fluid 1, in addition to the central inlet channel 5, a drain channel 6 is required at the edge, and for fluid 2, an inlet channel 7 is required in addition to the central outlet channel 8 at the edge. As can be seen from a section through a heat exchanger cartridge shown in FIG. 2, these edge channels described in FIG. 1 can be formed by recesses 6 and 7 in an enveloping body 10 that otherwise closely surrounds the reel 9 shown in FIG. This envelope 10 may for example consist of a cladding tube, which is additionally poured with casting resin, and also serves as a pressure envelope.

In addition to the wound design, of course, other geometric configurations of the film heat exchanger are conceivable, such. a plate geometry with foils and grids. However, it may be necessary to use massive components in addition to absorbing compressive forces.

Claims

claims

1. A device for transferring heat between engine oil and cooling water in vehicles, in which mutually adjacent flow channels of the engine oil and the cooling water are formed by a careful interspacing carried out succession of thin, elastic films, wherein the films as heat transfer surfaces between the respective flow channels serve, while preventing diffusion of engine oil and water between the respective flow channels, and the films are designed to be resistant to a predetermined, defined maximum temperature and for a specific predetermined operating time.

2. Device according to claim 1, wherein the maximum temperature is 150 ⁰ C and the operating time 5000 h.

3. Device according to claim 1 or 2, wherein the films are suitably coated or coextruded.

4. Apparatus according to claim 1, 2 or 3, wherein the foils are made of a material selected from a group consisting of PEEK, PTFE and PPSU.

5. Device according to one of the preceding claims, wherein means are provided for equalizing the respective flows and for increasing flow turbulences in the respective flow channels.

6. Apparatus according to claim 5, wherein the means are designed as grids.

The device of claim 6, wherein the grids are made of PA.

8. Device according to one of the preceding claims, wherein the films are welded together at front sides of the device, in particular sealed with casting resin.

9. Device according to one of the preceding claims, wherein the films have a surface structure by means of which respective defined flow channels are formed.

10. Device according to one of the preceding claims, wherein the films are spirally wound around at least one common axis, so that substantially respective, spiral-shaped flow channels are formed.

11. Device according to one of the preceding claims, wherein at least one additional, enclosed by a membrane with micropores channel is provided, whereby an engine oil filtration is feasible.

12. A method for transferring heat between engine oil and cooling water in vehicles, wherein each adjacent flow channels of the engine oil and the cooling water are formed by maintaining specific distances performed superimposition of thin elastic films, wherein the films serve as heat transfer surfaces between the respective flow channels while preventing diffusion of engine oil and water between the respective flow channels, and the foils are adapted to a predetermined, defined maximum temperature and to be stable for a specific predetermined operating time.

The method of claim 12, wherein the films are suitably coated or coextruded.

14. The method of claim 12 or 13, wherein in the respective flow channels means for equalizing the respective flows and increasing the flow turbulence are provided and the means are in particular designed as grids.

15. The method of claim 12, wherein the films are spirally wound around at least one common axis to form substantially respective spiral flow channels.