FR3086211A1 - ELECTRIC RADIATOR OF A VENTILATION, HEATING AND / OR AIR CONDITIONING SYSTEM OF A MOTOR VEHICLE - Google Patents

Abstract

The invention relates to an electric radiator (4) of a ventilation, heating and / or air conditioning installation of a motor vehicle, said radiator comprising at least one frame (12) for receiving one or more heating elements ( 14) comprising at least one tube (15) inside which are placed resistive elements (18), the frame (12) comprising faces (28, 29) perforated so as to allow a flow of air conveyed by the installation and passing through the radiator between the tubes in a first main direction of circulation, said radiator comprising a heat sink (32) disposed opposite one of the perforated faces of the frame and comprising branches (36, 361, 62) s 'extending in series in a second direction perpendicular to the first direction, the arms of the dissipator opposite the perforated face of the frame being respectively arranged in the extension of a tube (15) in the first direction.

Description

The field of the present invention relates to the field of ventilation, heating, and / or air conditioning of a motor vehicle, and it relates more particularly to the use of electric radiators in ventilation, heating and / or air conditioning devices.

The use of electric radiators in ventilation, heating and / or air conditioning installation boxes is known in particular for producing additional radiators arranged across the air flow at the outlet of a main radiator to generate an additional contribution. temporary heat energy, especially when starting the vehicle, to quickly heat up the air flow.

It is notably known to use electric heaters comprising a frame in which heating elements are housed, these heating elements comprising stones or ceramics with PTC effect, that is to say with a positive temperature coefficient. More particularly, it is known to have alternating tubes forming said heating elements and radiant elements in a reception frame. In particular, each tube has a sheath inside which are arranged two electrodes separated from each other by a plurality of resistive elements with PTC effect (positive temperature coefficient). The two electrodes of each tube are connected to a control electronics, and an electrical contact is created inside the tube between the electrodes and the resistive elements: the current supply of the resistive elements via these electrodes generates a heating of the tube forming the heating element, the calories being able to be diffused by the radiant elements made integral with the tubes and extending between two neighboring tubes, these radiant elements increasing the surface of exchange with the air passing through these electric radiators.

It is planned to equip motor vehicles more regularly with a high-voltage power supply network. And in this context, electric radiators can no longer be used only as an auxiliary heating source but as a main heating device, the calorific power that can be delivered by these high-voltage electric radiators being sufficient to heat the air

-2in the ventilation, heating and / or air conditioning installation. It follows from this application that the power electronics components arranged in the control interface for controlling the heating elements are caused in operation to give off a greater amount of heat than previously. It is therefore planned to associate these power electronics components with at least one heat sink.

The invention falls within this context and aims, according to a first aspect of the invention, to propose an electric radiator for a ventilation, heating and / or air conditioning installation of a motor vehicle, said radiator comprising at less a frame for receiving one or more heating elements respectively taking the form of a tube, the frame comprising perforated faces so as to allow a flow of air carried by the installation and passing through the radiator between the tubes according to a first main direction of circulation, said radiator further comprising an electronic control interface disposed at one end of the frame and a heat sink disposed opposite one of the perforated faces of the frame, the heat sink having branches extending in series in a second direction perpendicular to the first main direction of air circulation, the heat sink both disposed relative to the frame so that each branch is arranged in the extension of a tube forming the heating element in the first direction.

According to different characteristics of the invention, taken alone or in combination, it can be provided that:

- The heat sink has a common base for connecting each of the branches, said common base extending at least in part in the electronic control interface;

- the common base for connection of each of the branches of the heat sink forms a support for at least one power electronics component of said control electronics interface;

the branches of the heat sink extend partially in length, along a third direction perpendicular to the first and second directions mentioned above, on one of the faces of the frame of the electric radiator, with a covering length of the order of 15 to 30% of the total length of the frame;

the branches of the heat sink are arranged in transverse series with two end branches disposed respectively at one of the ends of said series and a plurality of central branches arranged between the end branches, the central branches having identical shapes l 'to each other;

- the end branches have a straight shape, with a dimension in the second direction which is constant over the entire length;

- The central branches have a tapered shape, with a dimension in the second direction which is variable, said dimension being smaller at the end of the branch remote from the electronic control interface than at the level of the end of the branch close to the electronic control interface;

- The dimension in the second direction of the central branches at the end near the electronic control interface is substantially equal to the corresponding dimension of the tubes forming the heating elements;

- The frame comprises longitudinal bars arranged across at least one perforated face of the frame, said longitudinal bars being arranged respectively in the axial extension of a tube forming the heating element in the first direction;

- the longitudinal bars and the branches of the heat sink are configured so that a tube, a bar and a branch are arranged in series in the first main direction;

- The dimension in the second direction of the longitudinal bars is less than the corresponding dimension of the tubes;

- in the assembly formed by a tube, a bar and a branch arranged in series, the longitudinal bar is arranged between the tube forming a heating element and the branch of the heat sink; in this way, the air passages between two tubes are configured so that the air flow meets only the radiant elements.

The invention relates, according to a second aspect of the invention, to a ventilation, heating and / or air conditioning installation of a motor vehicle in which an electric radiator as previously described is arranged across a circulation duct of air, so that the perforated faces of the radiator frame are arranged perpendicular to the direction of the air flow flowing in said duct, the perforated faces of the radiator then taking the function of an inlet face of air and an air outlet face.

According to a characteristic of this aspect of the invention, the heat sink is arranged opposite an air intake face of the radiator.

Other details, characteristics and advantages will emerge more clearly on reading the detailed description given below for information only in relation to the associated figures, among which:

- Figure 1 illustrates a ventilation installation unit, heating, and / or air conditioning according to one aspect of the invention and with a perspective angle making visible a plurality of air outlets and an electronic interface of control of an electric radiator arranged across a circulation duct internal to the housing;

- Figure 2 schematically illustrates an electric radiator according to one aspect of the invention configured to cooperate with a ventilation installation unit, heating and / or air conditioning such as that illustrated in Figure 1, making visible the interface d control electronics and a heating body in which are arranged heating elements, a heat sink being arranged between the interface of control electronics and the heating body;

- Figure 3 is a front view of the electric heater of Figure 2, rendering

-5visible the alignment of branches of the heat sink and the alignment of stiffening bars with tubes forming the heating elements of the radiator;

- Figure 4 is a perspective view in which the housing of the control electronics interface has been removed to make visible the fixing of power electronics components on the base of the heat sink visible in Figure 3;

- Figure 5 is a perspective view of a cross section along the plane illustrated in Figure 3, making visible the alignment of the tubes with on the one hand the branches of the heat sink and on the other hand the longitudinal bars of the frame ;

- And Figure 6 is a detail view of two portions of neighboring tubes and two portions of neighboring branches of the heat sink.

In the description which follows, reference will be made to an orientation which is a function of the Longitudinal, Vertical and Transversal axes as they are arbitrarily defined by the trihedron L, V, T represented in FIGS. 1 to 6. The choice of names for these axes is not limitative of the orientation that the device can take in its application to a motor vehicle, and the use of terms such as "upper" and "lower" is chosen according to the orientation in the illustration accompanying this description without being either limiting.

Reference is made to the figures to describe the electric radiator according to the invention, in particular in its integration into a housing of a ventilation, heating and / or air conditioning installation, so as to transform the electrical energy taken from the vehicle into thermal energy. returned to the air passing through said ventilation, heating and / or air conditioning installation.

In FIGS. 1 and 2, a housing 1 of a ventilation, heating and / or air conditioning installation has been made visible.

The housing 1 has an air inlet which is not visible here and a plurality of air outlets 2, capable respectively of supplying several zones of the passenger compartment with air brought to the appropriate temperature after it has passed through conduits delimited in the housing.

-6and in which are arranged heat exchangers, and in particular a particular electric heater 4 as will be described below.

Of course, the housing 1 is connected to different pipes, not shown here and forming part of the ventilation, heating and / or air conditioning installation, to convey the fresh air entering the housing and to convey the air treated by the housing to the desired cabin areas.

The box 1 of the ventilation, heating and / or air conditioning installation comprises a cavity 6 opening onto one of the side faces of the box and dimensioned to receive at least the electric radiator 4 so that the latter is arranged in through an air circulation duct inside the housing. As illustrated in FIG. 1, the cavity 6 can be dimensioned so as to receive, where appropriate, a main heat exchanger which is arranged upstream of the electric radiator relative to the air circulation duct. The main extension direction of the electric radiator corresponds to the direction of insertion of the radiator into the cavity 6.

The electric radiator 4 comprises an electronic control interface 8 which, as can be seen in FIG. 1, is accessible from outside the housing to allow the electric connection of the electric radiator, via this interface, to an electric network of the vehicle.

We will now describe in more detail the electric radiator 4 with reference to FIGS. 2 to 6.

The electric heater 4, which is capable of transforming an electric current into thermal energy, comprises, in addition to the electronic control interface 8, a heating body 10 (visible in FIGS. 2 and 3).

The heating body 10 comprises a frame 12 and a plurality of heating elements 14 arranged longitudinally in the frame 12, that is to say arranged in the main elongation direction of the electric radiator, said heating elements being arranged one next to the others in a transverse series perpendicular to the main direction of elongation of the electric heater.

-7As shown in particular in FIGS. 5 and 6, each of these heating elements 14 comprises a tube 15 inside which is placed a pair of electrodes 16 enclosing resistive elements 18 with a positive temperature coefficient, namely in this case PTC stones or ceramics, each electrode being electrically connected to the electronic control interface.

More particularly, each tube 15 has two side walls 150 arranged in opposition and against the internal face of which extend the electrodes 16, and two transverse walls 152 connecting two by two the side walls. The side walls each form a large face of the tube, these large faces facing each other between two neighboring tubes, and the transverse walls each form a small face.

For each tube 15 of a heating element 14, the resistive elements can be six in number, and are arranged along the direction of elongation X at equal distance from each other, it being understood that one configuration and another number of resistive elements could be implemented without departing from the context of the invention. However, it should be noted that all the resistive elements of the same heating element generate heat as soon as a current is sent to the electrodes that this heating element contains.

Radiant elements 20 are fixed, for example by gluing or by brazing, on one of the tubes 15 to increase the exchange surface with the air passing through the electric heating device, the air being brought to recover calories. releasing radiant elements following their heating by thermal conduction from the resistive elements. Between the radiant elements and the tubes, an electrical insulator can be placed as a safety measure.

The radiant elements 20 can in particular be produced by a corrugated sheet and take the form of fins to optimize the exchange of calories between the heating body 10 and the air passing through the electric radiator.

The frame 12 of the heating body is delimited longitudinally at one end by the electronic control interface 8 and at the longitudinal end opposite by

-8a bottom wall 22 forming an end stop for inserting the heating elements into the cavity. The electric radiator 4 is positioned in the cavity by means of positioning means 24 arranged on the external face of the bottom wall 22 and it is fixed in this cavity by means of fixing means 26 formed at the level of the control electronics interface 8.

The electronic control interface 8 consists of a housing for receiving electronic components configured to receive information, process it and generate a control instruction for controlling the heating elements.

At least the frame 12 of the heating body is made of a plastic material, for example polypropylene or polyamide, loaded with glass fibers. For example, the material used could be PA66 + GF30.

The frame 12 has the shape of a rectangular parallelepiped whose two main faces 28, 29 are perforated to allow the passage of air through the electric radiator between the tubes 15 in a first main direction of circulation and thus allow the diffusion of the heat given off by the heating elements housed inside the frame. The electric radiator is inserted into the cavity formed for this purpose in the housing of the ventilation, heating and / or ventilation installation, so that its perforated faces, or main faces, 28, 29 are arranged across of the air circulation path.

The main faces 28, 29 are extended perpendicularly, to connect them to each other, by two longitudinal side walls 30, 31 which delimit the frame transversely. The housing of the heating elements in the frame is thus delimited, between the two main faces 28, 29 by the longitudinal side walls 30, 31 by the bottom wall 22 and by the electronic control interface 8.

As will be described in more detail below, the frame 12 may include longitudinal bars 120 which extend across one or the other of the main faces. Where appropriate, and as can be seen in FIGS. 2 and 3, the frame 12 comprises transverse bars 121 coming to form a grid with the longitudinal bars 120. The bars 121 extend substantially perpendicular to these

-9 longitudinal bars, and it should be noted that the bars extend across the corresponding perforated face while being disposed opposite a portion of each of the tubes 15.

The frame 12 is dimensioned to define one or more receptacles for receiving one or more heating elements. For each heating element a defined number of tubes and radiant elements can be chosen. For example, a heating element can comprise four tubes 15 and five radiant elements 20.

As seen above, the electric radiator is positioned in the cavity 6 of the ventilation, heating and / or air conditioning installation so that the main faces 28, 29 are arranged across the circulation path of air. With reference to FIG. 2, it is then possible to define a first main face as an inlet face 28, through which the air enters the electric radiator, and an outlet face 29, through which the heated air comes out of the electric heater.

FIG. 2 more particularly illustrates the entry face 28, and it makes visible a heat sink 32 arranged opposite an openwork face of the frame, here therefore the entry face of the frame.

The heat sink 32 has a common base 34 and a plurality of legs 36 which extend respectively parallel from the common base. More particularly, the branches 36 extend in series transversely, that is to say in a direction parallel to the transverse direction of the series of tubes forming the heating elements.

A first direction can be arbitrarily defined as the main direction of air circulation through the radiator, perpendicular to the main faces as previously described, a second direction which corresponds to the transverse direction of the series of branches or of the series of tubes. , the second direction being perpendicular to the first main direction of air circulation, and a third direction which corresponds to the longitudinal direction of elongation of the electric radiator, the third direction being perpendicular to the first and second directions.

- 10As illustrated in the figures, and in particular visible in Figures 3, 5 and 6, the heat sink 32 is configured and arranged relative to the frame so that the branches 36 arranged across one of the perforated faces of the frame are respectively arranged in the extension, in the first direction, of one of the tubes forming the heating elements.

The common base 34 extends at least in part in the electronic control command interface. FIG. 3 makes in particular visible the part of the common base housed in the electronic control interface.

The control electronics interface also houses at least one printed circuit and power electronics components capable of electrically supplying the heating elements and controlling their operation.

The electric radiator is here, without however limiting the invention, a so-called high voltage electric radiator, that is to say intended to be supplied by a direct or alternating current having an electric voltage greater than 60V, by example between 180V and 1000V, and / or allowing to release a heating power on the air or a consumed electric power greater than 2kW, and for example between 2kW and lOkW.

In this context, a plurality of power electronics components 38 here taking the form of IGBT transistors are arranged against one face of the common base 34, if necessary held by a clip made integral with this common base.

The calories released by the operation of the power electronics components 38 are removed from the control electronics interface, and if possible dissipated in the air passing through the electric radiator, via the branches 36 of the heat sink 32. More particularly , by thermal conductivity, the calories stored at the level of the common branch 34 housed in the housing of the electronic control interface are directed towards the branches 36 disposed outside of

-11this interface. The heat sink is advantageously made of aluminum to facilitate the removal of heat by thermal conductivity.

As illustrated in FIG. 3, and as previously mentioned, the branches 36 of the heat sink arranged across one of the perforated faces of the frame are respectively arranged in the extension of a tube forming a heating element. In this way, it is understood that the air brought through the electric radiator passing between two neighboring tubes is not hampered by the presence of a branch of the heat sink. The pressure drop which results from the presence of the heat sink is thus zero or at the very least limited. As will be described in more detail below, the branches are also dimensioned to be arranged as close as possible to the passage of air between the tubes so that their lateral flanks are in contact with the passing air and that calories can be exchanged with air.

More particularly, FIG. 3 illustrates that one can distinguish the branches 36 of the heat sink 32, arranged in transverse series from the common base 34, by identifying two end branches 361 respectively disposed at one of the ends of the series transverse branches and a plurality of central branches 362 disposed between the end branches.

The end branches 361 are disposed respectively opposite a longitudinal wall 30, 31 of the frame, that is to say on the edge of the perforated face through which the air flow passes through the electric radiator. These end branches have a straight and regular shape, that is to say a width, or dimension in the second direction, which is constant over the entire length, or dimension in the third direction, of the end branch . Where appropriate, these end branches 361 form a contact surface with the frame 12 of the electric heater.

The central branches 362 have a shape which is identical to each other and which may be different from that of the end branches 361 previously described. More particularly, the central branches 362 have a width, or dimension in the second direction, which is equivalent to the corresponding width of the tubes 15 opposite which these branches extend. In this way and as has been described, the

-12position of the central branches is an optimal compromise between the interest of the contact of the heat sink with the air for the dissipation of calories and the clearing of the branches of the air path to limit the pressure drop.

More particularly, the branches 36 of the heat sink have an external face 363, turned away from the frame of the electric radiator, and lateral flanks 364, arranged opposite a lateral flank of a neighboring branch 36. Advantageously, the lateral flanks 364 are arranged in the axial extension, in the first main direction of the air flow passing through the radiator, from the lateral walls 150 of the tubes 15.

In the example illustrated, the central branches 362 have a tapered shape, with a dimension in the second direction which is variable so as to present a distal part, opposite the common branch, of the same width as that of the tubes as previously described and so as to present a part proximal to the junction with the common branch wider than the distal part to stiffen the branches.

The branches 36 of the heat sink 32 extend here over the entire width of the frame, that is to say over the entire transverse dimension in the second direction, and they extend in length, along the third direction, partially covering the openwork face. More particularly, the length of the branches relative to that of the frame is such that the overlap length can be of the order of 15 to 30% of the total length of the frame.

We will now describe the arrangement of the longitudinal bars 120 extending across one of the main openwork faces of the frame, that is to say across the outlet face and / or the inlet face of air.

In the example illustrated, the air inlet face 28 is described, namely the face where the heat sink 32 is arranged, without this being limiting of the invention. The characteristics specific to the longitudinal bars 120 can thus be understood as well in the context of use across an inlet 28 or outlet 29 face, it being understood that the characteristics in combination with the branches 36 of the

- 13 heat sink 32 will be more advantageously included in the context of an implementation of these longitudinal bars across an inlet face 28.

The frame thus comprises longitudinal bars 120 arranged across at least one perforated face of the frame, parallel to each other and parallel to the longitudinal walls 30, 31 participating in delimiting the frame 12 transversely.

As illustrated in Figures 3, 5 and 6, the longitudinal bars are respectively arranged in the axial extension, in the first direction, of one of the tubes forming a heating element.

The dimension in the second direction of the longitudinal bars 120 is less than the corresponding dimension of the tubes 15, that is to say the width of the transverse walls 152. It follows from the above that the axial projection of the longitudinal bars is entirely inscribed in the transverse wall 152 of the tube directly opposite the corresponding longitudinal bar.

In accordance with what has been described above, the air flow brought through the electric radiator between the tubes 15 is thus not hampered by the presence of the longitudinal bars, and the pressure drop due to the presence of the longitudinal bars 120 across the openwork faces is zero or at the very least limited.

Figures 5 and 6 illustrate more particularly an embodiment in which the frame 12 is provided with longitudinal bars 120 as previously described and a heat sink 32 whose branches 36, at least the central branches 362, are arranged in the axial alignment of the tubes 15.

More particularly, the heating elements, the frame and the heat sink are here configured so that a tube forming a heating element, a longitudinal bar of the frame and a branch of the heat sink are arranged in series along the first main direction, c that is, the direction of air flow through the radiator. It is understood that in this way, the air passages between two tubes are such that the air flow meets only the radiant elements.

- 14As illustrated, the longitudinal bar 120 is disposed between the tube forming a heating element, and more particularly a transverse wall 152 of this tube 15, and the branch 36, more particularly the central branch 362 of the heat sink 32. This arrangement is here advantageous in that the heat sink 32 is arranged opposite the air inlet face and therefore capable of being in contact with fresh air. It is therefore desirable that the entire surface of a branch is clear and capable of being in contact with fresh air, without being covered by a longitudinal bar 120.

The invention as it has just been described achieves the goals it has set itself, in that it makes it possible to limit the pressure drop of the air flow when passing through the electric radiator.

The invention as it has just been described cannot however be limited to the radiator and to the installation described and illustrated, and in particular to the examples described with a defined number of heating elements, provided that provision is made for '' Specifically arrange the position of a heat sink, and more particularly its branches, and / or stiffening devices of the frame, and more particularly of longitudinal bars, relative to the position of tubes constituting heating elements, such that the constituent elements of the dissipator or of the stiffening devices are in the axial space requirement of the tubes and are not an additional obstacle to the path of the air with respect to the presence of the tubes.

Claims (10)

1. Electric radiator (4) of a ventilation, heating and / or air conditioning installation of a motor vehicle, said radiator comprising at least one frame (12) for receiving one or more heating elements (14) comprising at least one tube (15) inside which are arranged resistive elements (18), the frame (12) having faces (28, 29) perforated so as to allow a flow of air carried by the installation to pass and passing through the radiator between the tubes in a first main direction of circulation, said radiator further comprising an electronic control interface (8) disposed at one end of the frame and a heat sink (32) disposed opposite one of perforated sides of the frame, the heat sink (32) comprising branches (36, 361, 62) extending in series in a second direction perpendicular to the first main direction of air circulation, the heat sink r thermal being disposed relative to the frame so that the branches (36, 362) arranged opposite the perforated face of the frame are respectively arranged in the extension of a tube (15) in the first direction. 2. Electric radiator according to claim 1, characterized in that the heat sink (32) comprises a common base (34) for connection of each of the branches (36, 631, 632), said common base extending at least in part in the control electronics interface (8). 3. Electric radiator according to claim 2, characterized in that the common connection base (34) of each of the branches of the heat sink (32) forms a support for at least one power electronics component (38) of said interface d 'control electronics (8). 4. Electric heater according to one of the preceding claims, characterized in that the branches (36, 361, 362) of the heat sink (32) extend partially in length, along a third direction perpendicular to the first and second aforementioned directions, on one of the faces of the frame (12) of the electric radiator (4), with an overlap length of the order of 15 to 30% of the total length of the frame. 5. Electric radiator according to one of the preceding claims, characterized in that the branches of the heat sink (32) are arranged in transverse series with two end branches (361) disposed respectively at one of the ends of said series and a plurality of central branches (362) disposed between the end branches, the central branches having identical shapes to each other. 6. Electric heater according to the preceding claim, characterized in that the end branches (361) have a straight shape, with a dimension in the second direction which is constant over the entire length. 7. Electric radiator according to claim 5 or 6, characterized in that the central branches (362) have a tapered shape, with a dimension in the second direction which is variable, said dimension being smaller at the end of the branch distant from the control electronics interface (8) only at the end of the branch close to the control electronics interface. 8. Electric heater according to one of claims 5 to 7, characterized in that the dimension in the second direction of the central branches (362) at the end near the electronic control interface is substantially equal to the corresponding dimension of the tubes (15) forming heating elements. 9. Installation for ventilating, heating and / or air conditioning a motor vehicle in which an electric radiator (4) according to one of the preceding claims is arranged across an air circulation duct, so as to that the perforated faces (28, 29) of the frame (12) of the radiator are arranged perpendicular to the direction of the air flow flowing in said duct, the perforated faces of the radiator then taking the function of an inlet face d 'air (28) and an air outlet face (29). 10. Installation according to the preceding claim, characterized in that the heat sink (32) is arranged opposite an air intake face (28) of the radiator.