WO2018229082A1 - Ventilation device for a motor vehicle - Google Patents

Abstract

The invention relates to a ventilation system for generating an air flow in the direction of a motor vehicle heat exchanger (1), comprising ducts (3), each of which is provided with at least one opening for ejecting an air flow, separate from its ends, and a device (20) for heating at least one of the ducts (3).

Description

 VENTILATION SYSTEM FOR MOTOR VEHICLE

The invention relates to a ventilation system for a motor vehicle.

The invention relates to the field of the automobile, 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 referred to as " 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 coolant and the ambient air, it is frequent that a ventilation device is used in addition, to generate or increase a flow of air directed to the tubes and the fins.

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

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

In addition, the distribution of the air vented by the propeller, often placed in the center of the row of tubes, is not homogeneous over the entire surface of the heat exchanger. In particular, some regions of the heat exchanger, such as the ends of the heat pipes and the corners of the heat exchanger, are not or only slightly reached by the air flow ejected by the propeller.

Moreover, when the start of the ventilation device is not necessary, especially when the heat exchange with the ambient air is sufficient to cool the coolant, the blades of the propeller partially obstruct or "mask" the flow of ambient air to the tubes and the fins. This limits the exchange of heat between the ambient air, on the one hand, and the tubes and fins, on the other hand.

Another disadvantage is that, when the outside temperature is low or negative, the fan propeller blows cold air on the heat exchanger, which has the effect of slowing the temperature rise of the vehicle engine.

Moreover, in this case, the friction of the engine is reduced less rapidly, which increases the consumption of the vehicle and therefore the emission of carbon dioxide.

An object of the invention is to provide a ventilation device for heat exchanger not having at least some of the disadvantages of known heat exchanger ventilation devices.

For this purpose, the subject of the invention is a ventilation system intended to generate an air flow towards a motor vehicle heat exchanger, comprising ducts, each duct being provided with at least one opening of ejecting a separate airflow from its ends, and a heater for at least one of the ducts.

Thus, advantageously, the plurality of ducts from which air is ejected makes it possible to replace the conventional propeller disposed in front of the circulation tubes of a heat transfer fluid of the heat exchanger, without presenting the disadvantages mentioned above.

Indeed, with equal heat exchange capacity, the volume occupied by such a ventilation device is much less than a propeller ventilation device. In addition, the distribution of air vented through the ducts is easier to control and can be made more homogeneous. In addition, thanks to the system according to the invention, it limits the obstruction of the flow of air to the heat exchanger. Indeed, the ducts of the ventilation system can advantageously be arranged opposite areas of low heat exchange of the heat exchanger, called "dead zones", such as the end faces of the tubes through which the coolant, which does not are not in contact with cooling fins. This is not possible with a conventional propeller.

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

In addition, the heating device provides a heating of the air supplying the heat exchanger associated with the engine cooling, which optimizes the temperature rise of the engine when the vehicle is started.

In addition, even if water, due to rain or moisture in the air, settles and freezes on the ventilation system, the heater ensures the defrosting of the ventilation system.

According to another characteristic of the invention, the heating device comprises at least one heating element, said at least one heating element being a screen-printed heating element or an electrical resistance.

According to another characteristic of the invention, said at least one screen-printed heating element has a thickness of between 0.2 mm and 1 mm.

According to another characteristic of the invention, said at least one heating element is disposed in contact with a wall, said heating wall, the heating wall being an inner wall of one of the tubes or an outer wall of the one of the tubes. According to another characteristic of the invention, said at least one heating element is glued or overmolded or secured by a holding member to said heating wall.

According to another characteristic of the invention, the heating device comprises an electrical source.

According to another characteristic of the invention, the duct or ducts are made from an electrically conductive material.

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

According to another characteristic of the invention, two adjacent ducts are arranged facing 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 to the other so that a flow of air set in motion by the ventilation system supplies air to the heat exchanger.

Other characteristics and advantages of the invention will appear on reading the description which follows. This is purely illustrative and should be read in conjunction with the attached drawings in which:

FIG. 1 illustrates a front view of a module for the exchange of heat equipped with a ventilation system according to the present invention;

FIG. 2 illustrates a cross-sectional view of two adjacent ducts of the ventilation system of FIG. 1;

FIG. 3 illustrates a perspective view of a duct of the ventilation system of FIG. 1 according to a first embodiment; and

- Figure 4 illustrates a perspective view of a duct of the ventilation system of Figure 1 according to a second 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 a flow of air set in motion by the ventilation system 1 supplies air the heat exchanger, preferably for cooling the engine of the motor vehicle.

Ventilation system

As can be seen in FIG. 1, the ventilation system 1 comprises a plurality of ducts 3.

The conduits 3 may in particular be substantially rectilinear, parallel to each other and aligned so as to form a row of tubes.

The ventilation system 1 also comprises an air supply device for an air flow F.

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

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

Advantageously, the supply circuit also comprises one or more turbomachines (not shown), for example a turbomachine disposed at the bottom of each manifold, for ejecting the air through the intake manifolds 5, into 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 can be seen in FIG. 2, each tube 3 has a cross section comprising a leading edge 1 1 free, a trailing edge 15 and first and second profiles 12, 14, each extending between the leading edge 1 1 and the trailing edge 15.

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

Each opening 10 is made in an outer wall 16 of the tube 3, preferably in one or other of the profiles 12, 14.

An internal wall of each tube 3 is referred to.

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

As also visible in Figure 2, the openings 10 of the pair of tubes 3 shown are formed in the profiles 12 facing each other. Thus, the ventilation tubes 3 and their openings 10 are configured so that the flow of air F flowing in the ventilation tubes 3 is ejected through the opening 10 by flowing along each profile 12, substantially until at their trailing edges 52, by Coanda effect.

The flow of air F ejected from the tubes 3 accelerates another flow F 'in a direction of flow to the heat exchanger.

It should be noted that the transverse cross-sections of the tubes 3 are such that the profiles 12 extend in a direction away from the tubes 3 from the leading edges 11 to the trailing edges 15.

Heating device

As shown in the figures, the ventilation system 1 comprises a heating device 20.

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

In the illustrated embodiments, the heater 20 comprises a plurality of heating elements 21.

The heating elements are advantageously screen-printed heating elements and / or electrical resistors.

Preferably, each screen-printed heating element has a thickness of between 0.2 mm and 1 mm.

These thickness values ensure that the heating elements minimize pressure drops.

Each electrical resistor may be in the form of a straight or spiral wire.

In the figures, the heating elements are spiral wires.

According to another variant, the electrical resistors are thermistors, for example thermistors with a positive temperature coefficient.

Each heating element 21 is placed in contact with the tubes 3.

According to a first embodiment illustrated in FIG. 3, the heating elements 21 are placed in contact with the inner wall 18 of each tube 3.

As can be seen in FIG. 3, each heating element 21 extends along the inner wall 18.

Advantageously, the heating elements 21 are parallel to each other.

Thus, the flow of air F flowing in the tube 3 before its ejection through the opening 10 is heated, which allows a heating of the heat exchanger associated with the ventilation system 1.

In addition, the outer wall 18 is indirectly heated, which can optionally defrost the outer wall 18 and release the passage of the air flow F '.

According to a second embodiment illustrated in FIG. 4, the heating elements 21 are arranged in contact with the outer wall 16 of each tube 3.

As can be seen in FIG. 4, each heating element 21 extends along the outer wall 16.

Advantageously, the heating elements 21 are parallel to each other.

Thus, the outer wall 18 is heated by the heating elements 21, which allows its defrosting and ensures the passage of the flow of air F '.

In addition, the inner wall 16 being heated indirectly, it is possible to heat the flow of air F flowing in the tube 3, which allows a heating of the heat exchanger associated with the ventilation system 1.

Subsequently, the heating wall 22 is called the wall in contact with which the heating elements 21 are arranged.

According to a first variant, the heating elements 21 are secured to the heating wall 22 by gluing.

For example, each heating element 21 may be contained in a sticker that simply sticks on the heating wall 22.

According to a second variant, each heating element 21 is overmoulded, for example in a plastic material at least partially forming the heating wall 22.

According to a third variant, the system 1 comprises a member for holding each heating element 21 to the tube 3.

For example, the holding member is a latching means, known by the term "clip", in particular elastomer.

Note that the heating elements may also be at least partially formed by the heating wall 22 made from an electrically conductive material.

The conductive material is preferably selected from an electrically conductive metal, or an electrically charged insulating substrate, or a material comprising a metal wire overmolded in a plastics material, or a polypropylene based resin provided with conductive fibers.

In particular, the conductive material may be a polypropylene resin provided with carbon fibers, comprising for example 20% by weight of carbon fibers. As can be seen in FIGS. 3 and 4, the heating device 10 comprises an electric source 23 for supplying the heating elements 21 with electricity.

Preferably, the electrical source 23 is a source of low current or low voltage, for example a few milliamperes or a few volts.

The electrical source 23 supplies the heating elements 21 at least at the start of the vehicle.

According to one embodiment, the electric source 23 is a source dedicated to the heating elements 21.

According to another embodiment, the electrical source 23 is an electrical control unit for another element of the ventilation system or the motor vehicle, such as an actuator for example.

Advantages

As already indicated, the system according to the present invention is self-defrosting and allows preheating of the heat exchanger with which it is associated.

The invention has been illustrated according to various embodiments, which, of course, are not limiting.

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

In addition, it is possible to combine several types of heating elements 21, on several tubes or on the same tube.

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

Similarly, the entire surface of the heating wall is covered with heating elements, or, on the contrary, the heating wall is covered only over part of its length, depending on the desired heating power.

Claims

1. Ventilation system for generating a flow of air to a motor vehicle heat exchanger (1), comprising: ducts (3), each duct being provided with at least one ejection opening (10) an air flow (F) distinct from its ends (6, 7), and a heater (20) of at least one of the ducts (3). 2. Ventilation system according to claim 1, wherein the heating device (20) comprises at least one heating element (21), said at least one heating element (21) being a screen-printed heating element or an electrical resistance. 3. Ventilation system according to the preceding claim, wherein said at least one screen-printed heating element (21) has a thickness of between 0.2 mm and 1 mm. 4. Ventilation system according to one of claims 2 or 3, wherein said at least one heating element (21) is disposed in contact with a wall, said heating wall (22), the heating wall (22). ) being an inner wall (18) of one of the conduits (3) or an outer wall (16) of one of the conduits (3). 5. Ventilation system according to the preceding claim, wherein said at least one heating element (21) is glued or overmolded or secured by a holding member to said heating wall (22). 6. Ventilation system according to one of the preceding claims, wherein the heater (20) comprises an electrical source (23). 7. Ventilation system according to one of the preceding claims, wherein the at least one duct (3) is made from an electrically conductive material. 8. Ventilation system according to one of the preceding claims, wherein each duct (3) has a section comprising:  a leading edge (1 1),  a trailing edge (15) opposed to the leading edge (1 1),  first and second profiles (12, 14), each extending between the leading edge (1 1) and the trailing edge (15),  said at least one opening (10) of the duct (3) being on one of the first and second profiles (12, 14), said at least one aperture (10) being configured so that a flow of air exiting from the opening (10) flows along at least a portion of said one of the first and second profiles (12, 14). 9. Ventilation system according to the preceding claim, wherein two adjacent ducts are disposed opposite one another so that the openings (10) are formed in the profiles (12) facing each other. 10. 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 another so that a flow of air set in motion by the ventilation system supplies air to the heat exchanger.