FR3073610B1 - VENTILATION SYSTEM FOR MOTOR VEHICLE - Google Patents

Abstract

The invention relates to a ventilation system for generating an air flow towards a motor vehicle heat exchanger, comprising tubes (3), each tube (3) being provided with at least one opening of ejecting an air flow distinct from its ends, and a cooling device (20) for a fluid to be cooled.

Description

VENTILATION SYSTEM FOR MOTOR VEHICLE The invention relates to a ventilation system for a motor vehicle. The invention relates to the automotive field, and more particularly to the field of air circulation for cooling the engine and its equipment.

Motor vehicles, whether combustion or electric, need to evacuate the calories generated by their operation and are therefore equipped with heat exchangers. A motor vehicle heat exchanger generally comprises tubes, in which a heat transfer fluid is intended to circulate, in particular a liquid such as water, and heat exchange elements connected to these tubes, often designated by the term " fins >>. The fins increase the exchange surface between the tubes and the ambient air.

However, in order to further increase the heat exchange between the heat transfer fluid and the ambient air, it is frequent that a ventilation device is used in addition, to generate or increase a flow of air directed towards the tubes and the fins.

Such a ventilation device most often comprises a propeller fan, which has several drawbacks.

First, the assembly formed by the propeller fan and its motorization system occupies a large volume.

In addition, the distribution of air ventilated by the propeller, often placed in the center of the row of tubes, is not uniform over the entire surface of the heat exchanger. In particular, certain regions of the heat exchanger, such as the ends of the heat transfer tubes and the corners of the heat exchanger, are not or only slightly affected by the air flow ejected by the propeller.

Furthermore, when it is not necessary to start the ventilation device, in particular when the exchange of heat with the ambient air is sufficient to cool the heat transfer fluid, the propeller blades and the nozzle obstruct or " partially mask the flow of ambient air to the tubes and the fins. This limits the heat exchange between the ambient air, on the one hand, and the tubes and fins, on the other.

An object of the invention is to provide a ventilation system for heat exchanger which does not have at least some of the drawbacks of ventilation systems for known heat exchanger. To this end, the subject of the invention is a ventilation system intended to generate an air flow towards a heat exchanger of a motor vehicle, comprising tubes, each tube being provided with at least one opening for ejection of a separate air flow from its ends, and a device for cooling a fluid to be cooled.

Thus, advantageously, the plurality of tubes from which air is ejected makes it possible to replace the conventional propeller placed in front of the circulation tubes of a heat-transfer fluid from the heat exchanger, without having the drawbacks mentioned above.

Indeed, for equal heat exchange capacities, the volume occupied by such a ventilation device is much less than a propeller ventilation device. In addition, the distribution of air ventilated by the tubes is easier to control and can be made more homogeneous.

In addition, thanks to the system according to the invention, the obstruction of the flow of air to the heat exchanger is limited. In fact, the tubes of the ventilation system can advantageously be arranged opposite zones of low heat exchange of the heat exchanger, called "dead zones", such as the front faces of the tubes through which the heat transfer fluid passes, which are not in contact with cooling fins. This is not possible with a conventional propeller.

Furthermore, the invention makes it possible to offset the air ejection means supplying the tubes of the ventilation device with air flow, at a distance from the row of tubes for circulation of heat-transfer fluid, which offers more freedom in the design of the heat exchanger.

In addition, the ventilation system according to the present invention makes it possible to cool the engine coolant (the fluid to be cooled being in this case the engine coolant), either in place of the heat exchanger, or upstream or downstream of it. Thus, the necessary thermal load of the heat exchanger can be reduced. We can then reduce the dimensions of the heat exchanger, which reduces the size in the engine compartment of the vehicle, and reduces its weight and therefore the consumption of the vehicle.

According to another characteristic of the invention, the cooling device comprises at least one cooling channel configured to contain a cooling fluid.

According to another characteristic of the invention, said at least one cooling channel has an oblong or circular or oval section.

According to another characteristic of the invention, said at least one cooling channel is arranged in a wall of one of the tubes.

According to another characteristic of the invention, said at least one cooling channel is a lumen machined in the wall of one of the tubes.

According to another characteristic of the invention, said at least one cooling channel is arranged in contact with an internal surface of one of the tubes.

According to another characteristic of the invention, said at least one cooling channel is machined on the internal surface of one of the tubes or attached to it.

According to another characteristic of the invention, the system comprises a plurality of cooling channels, at least two channels being identical and / or at least two channels being different.

According to another characteristic of the invention, the system comprises a plurality of cooling channels configured so that a total passage section of the plurality of channels is between 100 mm2 and 500 mm2, and preferably between 200 mm2 and 300 mm2, and an exchange surface of between 0.2 m2 and 0.8 m2, preferably between 0.4 m2 and 0.6 m2.

According to another characteristic of the invention, each tube has a section comprising a leading edge, a trailing edge, opposite the leading edge, a first and a second profile, each extending between the leading edge and the trailing edge, said at least one opening of the tube being on one of the first and second profiles, said at least one opening being configured so that a flow of air leaving the opening flows along at least a portion of said one of the first and second profiles.

According to another characteristic of the invention, two adjacent tubes are arranged opposite one another so that the openings are made in the profiles facing each other. The invention also relates to a heat exchange module for a motor vehicle, comprising a ventilation system as described above, and a heat exchanger, the ventilation system and the heat exchanger being positioned relatively one to the other so that a flow of air set in motion by the ventilation system supplies air to the heat exchanger.

According to another characteristic of the invention, the heat exchanger comprises at least one heat exchange duct containing a heat exchange liquid, the cooling fluid of the at least one cooling channel of the cooling device of the cooling system being the heat exchange liquid, so that the ventilation system and the heat exchanger are in fluid connection with each other. Other characteristics and advantages of the invention will appear on reading the description which follows. This is purely illustrative and should be read with reference to the accompanying drawings in which: - Figure 1 illustrates a front view of a heat exchange module equipped with a ventilation system according to the present invention; - Figure 2 illustrates a cross-sectional view of two adjacent tubes of the ventilation system of Figure 1; - Figure 3 illustrates a sectional view of a tube of the ventilation system of Figure 1 according to a first embodiment; - Figure 4 illustrates a sectional view of a tube of the ventilation system of Figure 1 according to a second embodiment; and - Figure 5 illustrates a sectional view of a tube of the ventilation system of Figure 1 according to a third embodiment.

Heat exchange module The invention relates to a ventilation system 1 for a motor vehicle. The invention also relates to a heat exchange module 100, comprising the ventilation system 1 and a heat exchanger 101.

As shown in Figure 1, the ventilation system 1 and the heat exchanger 101 are positioned relative to each other so that an air flow set in motion by the ventilation system 1 supplies air the heat exchanger, preferably to cool the engine of the motor vehicle.

Ventilation system

As shown in FIG. 1, the ventilation system 1 comprises a plurality of tubes 3.

The tubes 3 are substantially rectilinear, mutually parallel and aligned so as to form a row of tubes.

The ventilation system 1 also comprises a device for supplying air with an air flow F.

This device feeds the ventilation tubes 3 via an air supply circuit 4.

The air supply circuit 4 comprises in particular two air intake manifolds 5 to which the ventilation tubes 3 are connected by means of air supply inlets located at each of their ends 6, 7.

Advantageously, the supply circuit also comprises one or more turbomachines (not shown), for example a turbomachine arranged at the foot of each manifold, for ejecting air through the intake manifolds 5, as far as the ventilation tubes 3 .

As more particularly visible in FIG. 2, each ventilation tube 3 comprises an opening 10 distinct from the ends 6, 7, for ejecting the air out of the tube 3.

Preferably, the openings 10 are intended to be arranged facing the heat exchanger.

As visible in FIG. 2, each tube 3 has a cross section comprising a free leading edge 11, a trailing edge 15 and a first and a second profile 12, 14, each extending between the leading edge 11 and the trailing edge 15.

The trailing edge 15 is preferably arranged opposite the heat exchanger.

Each opening 10 is made in a longitudinal wall 22 of the tube 3, preferably in one or the other of the profiles 12, 14.

The longitudinal wall is delimited by an external surface 16 and an internal surface 18.

In FIG. 2, each opening 10 is positioned close to the leading edge 11.

As also visible in Figure 2, the openings 10 of the pair of tubes 3 illustrated are formed in the profiles 12 facing each other.

Thus, the ventilation tubes 3 and their openings 10 are configured so that the air flow F circulating in the ventilation tubes 3 is ejected through the opening 10 by flowing along each profile 12, substantially up to at their trailing edges 52, by Coanda effect.

The flow of air F ejected from the tubes 3 makes it possible to accelerate another flow F ’in a direction of flow towards the heat exchanger.

Note that the cross sections of the tubes 3 are such that the profiles 12 extend in a direction of separation of the tubes 3 from the leading edges 11 to the trailing edges 15.

Cooling device

As can be seen in the figures, the ventilation system 1 comprises a cooling device 20.

The cooling device 20 comprises at least one cooling element 21.

In the illustrated embodiments, the cooling device 20 comprises a plurality of cooling elements 21.

The cooling elements are advantageously cooling channels configured to contain a cooling liquid.

According to a first embodiment illustrated in FIG. 3, the cooling channels are arranged in the wall 22 of the tube 3.

Advantageously, the channels 21 are parallel to each other, and parallel to a longitudinal direction L of the tube 3.

Preferably, the channels 21 are slots machined in the wall of the tubes 3.

In FIG. 3, the tube 3 comprises sixteen cooling channels 21.

Preferably, each cooling channel 21 has a section of 1 mm in diameter.

This diameter value makes it possible to circulate the coolant while avoiding reducing the passage section of the air flow F in the tube 3.

Advantageously, the ventilation system 1 comprises twenty tubes 3, which makes it possible to reach a total passage section of the order of 250 mm2, and an exchange surface of approximately 0.5 m2.

This total passage section corresponds to approximately 1/3 of a total passage section of a conventional radiator.

This exchange surface corresponds to approximately 75% of a conventional radiator. The gap between the passage section and the exchange surface comes from the geometry of the channels. Indeed, small cylindrical conduits have the advantage of a large surface compared to the volume compared to radiator tubes.

Advantageously, for each ventilation system 1, the number and the diameter of the channels can vary according to the cooling needs.

The fluid to be cooled is preferably the coolant of the vehicle engine cooling circuit.

According to a variant, the fluid to be cooled is the air flow F.

In this case, according to this first embodiment, the air flow F is cooled during its circulation in the tube 3 before it is ejected through the opening 3.

Thus, each tube 3 provides a pre-thermalization of the air flow to the heat exchanger 101, which advantageously makes it possible to reduce the size of the heat exchanger.

The cooling channels 21 being integrated into the wall of the tube, they do not disturb the flow of the air flow F in the tube 3.

According to a second embodiment illustrated in FIG. 4, the cooling channels 21 are arranged in contact with the internal surface 18 of the longitudinal wall of the tube 3.

Preferably, each channel 21 extends along the internal surface 18.

Advantageously, the channels 21 are parallel to each other.

According to this embodiment, the fluid to be cooled is advantageously the coolant of the vehicle engine cooling circuit.

According to a variant, the fluid to be cooled is the air flow F.

In this case, according to this embodiment, the coolant contained in the channels 21 exchanges directly with the air.

Each tube 3 provides a pre-thermalization of the air flow to the heat exchanger 101, which advantageously makes it possible to reduce the size of the heat exchanger.

The channels 21 can be machined in the material or else added a posteriori.

In FIGS. 3 and 4, the cooling channels 21 are of circular section, and identical to each other.

Of course, the invention is not limited to these configurations.

As illustrated in FIG. 5, at least certain channels 21 may have an oblong or oval cross section, or any other shape which fits within the thickness of the tube or on the wall of the latter.

The geometry of the channels 21 (whether positioned in the wall or against the internal surface 18) can be adapted to the shape of the tube 3 and it is entirely possible to have channels of any other shape as long as it ensures good mechanical strength of the tube and maximum cooling performance.

Similarly, depending on the mechanical strength and the desired cooling power, one chooses to distribute the channels 21 uniformly or on the contrary to vary their spacing.

In the embodiment of FIG. 5 for example, only the profile 14 is provided with channels 21, the profile 12 being devoid of it.

As indicated above, the coolant circulating in the channels 21 is advantageously the engine coolant.

Preferably, in this case, the module 100 is configured to fluidly connect the system 1 and the heat exchanger 101.

The system according to the invention makes it possible, in addition to or in replacement of the conventional radiator, to take advantage of the tubes of the blower grid to remove calories from the coolant.

Thus, the coolant channels housed in the blower tubes make it possible to improve the general cooling of the engine, in particular when air is blown into the tubes. The invention has been illustrated according to various embodiments, which, as already indicated, are not limiting.

In particular, the tubes are not necessarily profiled to allow a coanda effect.

In addition, provision may be made to combine several types of channels 21, on several tubes or on the same tube.

Likewise, each tube 3 is equipped with one or more channels 21, or, on the contrary, only some of the tubes 3 are equipped with heating element (s).

Similarly, the entire surface of the wall of the tube is provided with channels 21, or, on the contrary, the wall only includes channels 21 over a part of its length, depending on the desired cooling power.

Channels 21 can also be provided both in the longitudinal wall and on the internal wall.

Claims (7)

1. Ventilation system intended to generate an air flow towards a heat exchanger (101) of a motor vehicle, comprising: tubes (3), each tube (3) being provided with at least one opening d ejection (10) of an air flow (F) distinct from its ends (6, 7), and a cooling device (20) of a fluid to be cooled, in which the cooling device (20) comprises at least one cooling channel (21) configured to contain a cooling fluid, said at least one cooling channel (21) being: - of oblong, circular, or oval section, and - arranged in a wall of one of the tubes (3). 2. Ventilation system according to the preceding claim, wherein said at least one cooling channel (21) is a lumen machined in the wall of one of the tubes (3). 3. Ventilation system according to one of the preceding claims, wherein said at least one cooling channel (21) is arranged in contact with an internal surface (17) of one of the tubes (3). 4. Ventilation system according to the preceding claim, wherein said at least one cooling channel (21) is machined on the internal surface (18) of one of the tubes (3) or attached thereto. 5. Ventilation system according to one of the preceding claims, comprising a plurality of cooling channels (21) configured so that a total passage section of the plurality of channels (21) is between 100 mm2 and 500 mm2, and preferably between 200 mm2 and 300 mm2, and an exchange surface of between 0.2 m2 and 0.8 m2, preferably between 0.4 m2 and 0.6 m2. 6. Heat exchange module for a motor vehicle, comprising a ventilation system according to one of the preceding claims, and a heat exchanger, the ventilation system and the heat exchanger being positioned one relative to the other so that an air flow set in motion by the ventilation system supplies air to the heat exchanger. 7. exchange module according to the preceding claim, comprising a ventilation system according to one of claims 1 to 5, the heat exchanger comprising at least one heat exchange duct containing a heat exchange liquid, the fluid cooling the at least one cooling channel (21) of the cooling device of the cooling system being the heat exchange liquid, so that the ventilation system and the heat exchanger are in fluid connection with each other 'other.