WO2004017005A2

WO2004017005A2 - Planar heat exchanger, in particular for motor vehicle, and method for making same

Info

Publication number: WO2004017005A2
Application number: PCT/FR2003/002373
Authority: WO
Inventors: Michel Potier
Original assignee: Valeo Thermique Moteur
Priority date: 2002-08-08
Filing date: 2003-07-28
Publication date: 2004-02-26
Also published as: FR2843448B1; AU2003285349A8; AU2003285349A1; EP1527309A2; FR2843448A1; WO2004017005A3

Abstract

The invention concerns a heat exchanger comprising parallel tubes (10) arranged in a plane. Heat exchanging surfaces (32), for example cooling fins, are associated with the tubes (10). Said heat exchanging surfaces are oriented in the plane of the tubes (10) of the heat exchanger. Preferably, the tubes are obtained by extrusion. The exchanger is advantageously assembled by induction brazing. The exchanger has little space requirement in thickness and can be installed, for example, beneath a motor vehicle floor.

Description

Flat heat exchanger, in particular for a motor vehicle, and process for its manufacture

The invention relates to the field of heat exchangers, in particular for motor vehicles. More specifically, the invention relates to a heat exchanger comprising parallel heat exchange channels having a length and arranged in a plane, and heat exchange surfaces associated with the tubes, a heat transfer gas circulating in contact with these surfaces. heat exchange.

Modern vehicles include an increasing number of heat exchangers in order to best manage the thermal energy developed by the vehicle engine. The presence of these exchangers under the hood of the vehicle raises a number of problems. The exchangers are generally arranged in a vertical position at the front of the vehicle, so as to be traversed by a flow of cooling air when the vehicle is traveling. This arrangement results in superimposing the exchangers, which are then traversed by the same air flow, so that the cooling provided by the exchanger located in the background relative to the air flow is less effective. On the other hand, the exchangers occupy a large volume under the engine hood, the volume of which is limited.

There are also known exchangers arranged horizontally. A guide housing allows the air flow to be deflected so that it crosses the radiator cooling fins perpendicular to the plane of the latter.

The object of the present invention is in particular to provide a heat exchanger which overcomes these drawbacks and which, in particular, makes it possible to solve the problems of space requirements linked to the presence of a large number of exchangers on board vehicles. These objects are achieved, in accordance with the invention, by the fact that the heat exchange surfaces of the channels are oriented in the plane of the heat exchange channels, which makes it possible to create a thin heat exchanger.

Thanks to this feature, the exchanger can be arranged in the vehicle so that its plane is horizontal. When the vehicle is traveling, the flow of cooling air is parallel to the plane of the radiator and, therefore, to the generators of the heat exchange surfaces. This air flow licks the heat exchange surfaces so as to cool them.

Thanks to its horizontal position, the heat exchanger of the invention occupies a very small space in height. It can therefore be placed in places where a conventional type exchanger could not be placed, for example under the vehicle floor. It can thus be installed very easily without cluttering the small volume available under the engine hood.

Of course, this heat exchanger can also be arranged vertically or in an oblique position.

In a preferred embodiment, the heat exchange surfaces are oriented parallel to the heat exchange channels.

However, the exchange surfaces can also be oriented perpendicular to the heat exchange channels.

The heat exchange surfaces are preferably made up of planar fins, but they could have another shape, for example a corrugated shape. In this case, it is the generators of this form that are oriented in the plane of the heat exchange channels.

Additional or optional features of the invention are listed below:

- the heat exchange channels are tubes;

- the tubes are obtained by extrusion;

- the fins are flat and arranged in vertical planes; - The heat exchange channels open at their ends into manifolds having a thickness substantially equal to the thickness of the heat exchange channels;

the manifolds are each formed from a rolled and stamped sheet having lips between which the ends of the channels are introduced;

- The ends of the channels are locally rid of their heat exchange surfaces and introduced in a sealed manner in respective housings arranged between the lips of the manifolds; - The heat exchanger is installed horizontally under a floor of a motor vehicle;

- the exchanger has a protective grid on its underside;

- the heat exchanger is assembled by induction brazing;

- the thickness of the exchanger is between 15 mm and 20 mm.

Furthermore, the invention relates to a method of manufacturing the heat exchanger. According to this process:

extruding, in great length, a closed section profile comprising heat exchange surfaces; the long length profile is cut to length, so as to determine length tubes; removing the heat exchange surfaces at the ends of the tubes over a determined length to allow mounting of these ends in manifolds; the tubes are mounted on the manifolds; and the manifolds, the tubes and the pipes are brazed, preferably by induction.

Other characteristics and advantages of the present invention will appear on reading the following description of exemplary embodiments given by way of illustration with reference to the appended figures. In these figures:

- Figure 1 is a general plan view of a heat exchanger according to the present invention;

- Figure 2 is a side end view of the exchanger shown in Figure 1; - Figure 3 is a side view of the exchanger in a direction perpendicular to that of the representation of Figure 2;

- Figure 4 is a sectional view along line IV-IV of Figure 3 of the exchanger shown in Figures 1 to 3; - Figures 5 to 7 are respectively sectional views of the exchanger shown in Figure 1, along the lines V-V, VI-VI and VII-VII of the exchanger of Figure 1;

- ^~ "Figure 8 ^~ is ^~ a schematic view which represents the location of the exchanger of the invention under the floor of a motor vehicle; and

- Figure 9 is a partial sectional view of an exchanger according to another embodiment of the invention.

The exchanger of the invention shown in plan view in Figure 1 comprises a first manifold 4 and a second manifold 6. The manifolds 4 and 6 are in communication via a bundle 8 of parallel tubes 10 lying down. One end of each of the tubes 10 is connected to the manifold 4, while the other end of each tube is connected to the manifold 6. In the example shown, the manifold 4 is connected, at one of its ends, to an inlet pipe 12 for a heat transfer fluid, for example a cooling fluid, as shown schematically by the arrow 14, and, at its other end, to an outlet pipe 16 for the outlet of the heat transfer fluid, as shown schematically by the arrow 18.

In the example (Figure 4), the manifold 4 is split into two chambers 20 and 22 by an intermediate partition wall 24. A two-pass heat exchanger is thus produced. The heat transfer fluid first enters the chamber 20, which constitutes an inlet chamber, travels through the tubes 10 of the bundle 8 connected to the chamber 20 from right to left, according to the figures, as shown schematically by the arrows 26. After having passed through the tubes 10, the coolant enters the manifold 6 and returns to the chamber 22, as shown by the arrows 28. This characteristic is advantageous because it makes it possible to connect the inlet 12 and outlet 16 pipes to the same manifold and, therefore, to have them on the same side of the exchanger.

However, it goes without saying that it is not imperative and the exchanger of the invention could comprise only a single pass, or an odd number of passes, so that the inlet manifold and the manifold outlet would be connected to different manifolds.

As can be seen in Figures 6 and 7, the manifolds 4 and 6 have a flattened shape, rounded at each of their ends, this in order to reduce the overall size in height or thickness of the exchanger. Preferably, the height of the manifolds does not exceed that of the tubes 10, so as not to increase the vertical size of the exchanger. The inlet 12 and outlet 16 pipes have a cylindrical part 19 which gradually turns into a flattened part 21, so that to adapt to the ends of the manifold 4.

There is shown in Figure 5 a sectional view of a tube 10 of the exchanger. This tube has a closed section part 30, with which cooling surfaces 32 are associated. In the example shown, the closed section part consists of a flattened tube, rounded at its two ends, and comprising four partitions of separation 34, so as to delimit five parallel circulation channels 36 for the heat transfer fluid.

Of course, the closed section part could take other forms. It could be, for example, circular or square. Furthermore, it does not necessarily have a partition. However, the section shown in Figure 5 is advantageous because it once again reduces the overall height of the fluid circulation elements.

Cooling surfaces 32 are associated with the closed section part 30. In the example, they are constituted by fins arranged in vertical planes 38. The fins 32 are thus perpendicular to the longitudinal axis 40 of the section part closed 30. Of course, the fins could have another orientation. They could also be formed by non-planar surfaces, for example by corrugated surfaces having end regions in thermal contact with the part of closed section "30. In this case, the generators of these corrugated exchange surfaces are arranged parallel to the direction of circulation of the cooling air flow, so the heat exchanger is generally flat and has a reduced thickness.

Preferably, the tubes 10 are obtained by extrusion. This manufacturing process is particularly advantageous because that it allows the closed section portion 30 comprising the partition walls 34 and the fins 32 to be produced in a single operation. Long tubes are extruded which are then cut to the correct size. The fins 32 are then released at each end of the tubes 10, so as to leave only the closed section portion 30, as shown in FIG. 6. For example, the fins 32 at the ends of the tubes 10 are eliminated on a length of about 4 mm.

This part is then inserted into housings 42 of complementary shape provided in the manifolds 4 and 6 at regular intervals corresponding to the spacing of the tubes 10. Between the tubes, the manifolds 4 and 6 have a fully closed section, as shown in Figure 7, the lips 44 and 46 being contiguous and assembled to one another in a sealed manner. The manifolds 4 and 6 can thus be easily produced from rolled and stamped sheet metal.

The tubes having been inserted into the orifices 42 of the manifolds 4 and 6, the tubes 10, the manifolds and the pipes 12 and 14 are advantageously brazed by induction. One could also braze the exchanger in a conventional brazing furnace. Then, optionally, a protective grid 50 is fixed on the face of the exchanger intended to be oriented facing the ground.

There is shown in Figure 8 a schematic sectional view showing the location of the heat exchanger of the invention under a floor 52 of a motor vehicle. This arrangement is made possible by the very small vertical size of the exchanger, preferably between 15 mm and 20 mm. A protective grid 50 is arranged under the underside of the exchanger. The air flow 54 generated by the circulation of the vehicle traverses the tubes 10 in the direction of their length by licking the fins 32 while, in a conventional type exchanger, the air flow is oriented perpendicular to the plane of the exchanger and passes through the bundle of tubes.

In the embodiment described in Figures 1 to 7, the heat exchange surfaces 32 are oriented in the lengthwise direction of the closed section channels 30. However, this arrangement is not imperative and the surfaces d heat exchange 32 could also be oriented perpendicular to these channels 30.

Thus, as shown in FIG. 9, the heat exchange surfaces can be constituted by fine, wavy and parallel fins 56, traversed by tubes 10 of the exchanger. The fins 56 thus form exchange surfaces which are oriented perpendicular to the heat exchange channels. However, also in this embodiment, the exchanger is arranged horizontally and the cooling air flow 54 passes through the fins 56 by licking them and not by crossing the bundle of tubes, as seen in FIG. 9.

In a preferred application, the heat exchanger of the invention is produced in the form of a radiator through which the vehicle engine cooling fluid flows. It can also be used for other purposes and constitute for example a condenser of an air conditioning circuit traversed by a refrigerant.

Claims

claims

1. Heat exchanger comprising parallel heat exchange channels (30) having a length arranged in a plane and heat exchange surfaces (32; 56) associated with the heat exchange channels (30), a heat transfer gas (54) flowing in contact with these heat exchange surfaces (32), characterized in that the heat exchange surfaces (32) are oriented in the plane of the heat exchange channels (30).

2. Heat exchanger according to claim 1, characterized in that the heat exchange surfaces (32) are oriented parallel to the heat exchange channels (30).

3. Heat exchanger according to claim 1, characterized in that the heat exchange surfaces (56) are oriented perpendicular to the heat exchange channels (30).

4. Heat exchanger according to one of claims 1 to 3, characterized in that the heat exchange channels (30) are tubes (10).

5. Heat exchanger according to claim 4, characterized in that the tubes (10) are obtained, with the heat exchange surfaces (32), in a single operation by extrusion.

6. Heat exchanger according to one of claims 4 and 5, characterized in that the fins (32) are planar and arranged in vertical planes (38).

7. Heat exchanger according to one of claims 1 to 6, characterized in that the heat exchange channels (30) open at their ends in manifolds (4, 6) having a thickness substantially equal to the thickness of heat exchange channels (30).

8. Heat exchanger according to claim 7, characterized in that the manifolds (4, 6) are each formed from a rolled and stamped sheet having lips (44, 46) between which are introduced the ends of the channels (30).

9. Heat exchanger according to claim 8, characterized in that the ends of the channels (30) are cleared locally of their heat exchange surfaces (32) and introduced in a sealed manner in respective housings (42) arranged between the lips (44, 46) of the manifolds (4, 6).

10. Heat exchanger according to one of claims 1 to 9, characterized in that it is installed horizontally under a floor (52) of a motor vehicle.

11. Heat exchanger according to one of claims 1 to 10, characterized in that it comprises a protective grid (50) on its underside.

12. Heat exchanger according to one of claims 1 to 11, characterized in that it is assembled by induction brazing.

13. Heat exchanger according to one of claims 1 to 12, characterized in that its thickness is between 15 and 20 mm.

14. Method for manufacturing a heat exchanger according to one of claims 1 to 13, characterized in that:

extruding, in great length, a closed section profile (30) comprising heat exchange surfaces (32); the long profile is cut to length, so as to determine length tubes (10); removing the heat exchange surfaces (32) at the ends of the tubes over a determined length to allow mounting of these ends in manifolds (4); the tubes are mounted on the manifolds; the manifolds, the tubes and the pipes (12 and 14) are brazed, preferably by induction.