WO2020174197A1

WO2020174197A1 - Humidity detection intended for a front-end motor-fan of a motor vehicle

Info

Publication number: WO2020174197A1
Application number: PCT/FR2020/050398
Authority: WO
Inventors: Kamal Mourad; Lucien Le Curieux-Belfond
Original assignee: Valeo Systemes Thermiques
Priority date: 2019-02-28
Filing date: 2020-02-28
Publication date: 2020-09-03
Also published as: FR3093394B1; FR3093394A1

Abstract

The invention relates to an electronic board (1) configured to control an electric motor (500) of a front-end motor-fan (600) of a motor vehicle, the electronic board (1) comprising at least one microcontroller (2) and a plurality of conductive tracks. The electronic board (1) according to the invention comprises a humidity detection device (100), which comprises a first conductive track (3) configured to be brought to a first electric potential (300) and a second conductive track (4) configured to be brought to a second electric potential (400), different from the first electric potential (300), the first conductive track (3) and the second conductive track (4) being printed on the electronic board (1).

Description

HUMIDITY DETECTION INTENDED FOR A MOTOR VEHICLE FRONT PANEL FAN OF A MOTOR VEHICLE

[1] The invention relates to the field of rotating electrical machines for a motor vehicle. It finds a preferred, but not exclusive, application to rotating electrical machines operating as a motor for driving the fans of a motor vehicle in rotation such as, for example, a fan placed on the front face of the vehicle and intended to generate a air flow passing through at least one heat exchanger.

[2] Such fans include in particular a propeller driven in rotation by an electric motor which is itself controlled by an electronic power and control unit.

[3] In the event that it is associated with the electric motor, the electronic power supply and control unit is placed in an environment exposed, in particular, to humidity and water, and the components it contains. must therefore be protected. At least part of this electronic power supply and control unit is therefore placed in a sealed box. However, under the effect, for example, of leaks, moisture may be found inside such a housing, and this moisture may degrade the performance of the electronic power supply and control unit. check or damage components thereof.

[4] The aim of the invention is to provide a simple and inexpensive solution making it possible to know the level of humidity present in a sealed box receiving such an electronic power and control unit.

[5] For this purpose, the invention relates to an electronic card configured to control an electric motor of a front face fan of a motor vehicle, the electronic card comprising at least one microcontroller and a plurality of conductive tracks, characterized in that the electronic card comprises a humidity detection device.

[6] In other words, the invention provides that a humidity detection device is integrated into an electronic card of the electronic power supply and control unit of a fan as previously mentioned.

[7] Advantageously, the microcontroller carried by the electronic card according to the invention is configured to command and control the operation of the fan motor, as well as to achieve the desired humidity detection. Furthermore, conductive tracks carried by the electronic card according to the invention interconnect electronic components configured for powering and controlling the fan motor, as well as components configured for carrying out the measurements and calculations necessary for detection. desired humidity.

[8] According to one characteristic of the invention, the aforementioned humidity detection device comprises a first conductive track configured to be brought to a first potential. electrical and a second conductive track configured to be brought to a second electrical potential, different from the first electrical potential, the first conductive track and the second conductive track being printed on the electronic card.

[9] According to one example, the electronic card according to the invention is in the form of a substantially planar plate of small thickness. According to this example, the electronic card according to the invention comprises two main faces that are substantially parallel to one another, with the manufacturing tolerances close, separated from one another by walls whose dimensions are small compared to the dimensions of the aforementioned main faces. Advantageously, according to such an example, the first conductive track and the second conductive track are printed on a main face of the electronic card. According to one example, the first conductive track and the second conductive track are printed on the same main face of the electronic card.

[10] According to different variant embodiments, the aforementioned first electric potential and the second electric potential may be arbitrarily defined, or may be supply potentials for different components of the vehicle. By way of non-exclusive example, one of these electrical potentials may be a supply potential of the microcontroller placed on the electronic card according to the invention.

[11] It should be understood here that the detection of humidity carried out by means of the invention is based on the measurement of a variation of an electrical quantity in a portion of the circuit of the electronic card exposed to the internal atmosphere d 'a sealed box in which the electronic card according to the invention is placed. The measured electrical quantity can be, without limitation, a voltage measured at the terminals of the humidity detection device, or a current flowing in the latter. In what follows, the invention will be described and illustrated in the case where the measured electrical quantity is a voltage measured at the terminals of the humidity detection device.

[12] It follows from the above that according to the invention, the humidity detection device and, in particular, the first conductive track and the second conductive track previously mentioned, is therefore in contact with the interior atmosphere of a box in which the electronic card is placed. According to one example, the conductive tracks of the humidity detection device are devoid of a protective varnish.

[13] In the absence of humidity, the invention provides that there is no electrical contact between the first conductive track and the aforementioned second conductive track. A voltage, measured between these two conductive tracks, is therefore known.

[14] In the presence of humidity, an electrical contact is established between the first conductive track and the second conductive track, which generates a variation of the electrical quantity, for example a voltage, measured at the terminals of the detection device. humidity. Advantageously, the microcontroller placed on the electronic card according to the invention is configured to compare such a voltage with a previously defined threshold value and to transmit information representative of the result of this comparison to the vehicle, in order to avoid any damage to the components of the 'unit power supply and fan control. According to one example, the aforementioned threshold value is defined as a function of parameters specific to the vehicle in question: for example, this threshold value can be adjusted as a function of a voltage or a current delivered by a battery of the vehicle.

[15] It follows from the foregoing that the detection of humidity by means of the device according to the invention occurs as soon as the humidity, in the form of microdrops or drops of water extending simultaneously on the first track conductive and on the second conductive track, generates an electrical flow between these two tracks.

[16] Advantageously, the first conductive track and the second conductive track are separated from one another, on the electronic card according to the invention, by a distance of between 0.1 and 2.00 millimeters.

[17] It is thus noted that no electronic component of the electronic card is interposed between the first conductive track and the second conductive track. Furthermore, it is noted that the distance separating, on the electronic card according to the invention, the first conductive track and the second conductive track, is sufficiently reduced so that a small quantity of humidity, in the form of a microdrop, is sufficient. in generating an electrical contact between these two tracks. This makes it possible to increase the precision of the humidity detection, by reducing the minimum size of a microdrop of water detected by means of the invention.

[18] The electronic card according to the invention can also have one or more of the following characteristics, taken separately or in combination:

[19] - the first conductive track and the second conductive track each comprise a main track and a plurality of secondary tracks which extend from the main track. According to one example, the secondary tracks extend substantially perpendicular to the main track of the conductive track considered. In other words, the first conductive track and the second conductive track have substantially the form of combs, the teeth of which are mutually parallel. According to an exemplary embodiment, the length of the secondary tracks is substantially of the order of 2 to 100 millimeters, and the secondary tracks are separated from one another, on the main track from which they extend, by a distance of between CCC and DDD millimeters. According to such a configuration, the main tracks of the first conductive track and of the second conductive track provide the electrical connection between the secondary tracks of the conductive track considered between them and with the microcontroller to which the conductive track considered is electrically connected. In such a configuration, the desired humidity detection is achieved when a microdrop of water generates an electrical circulation between a secondary track of the first conductive track and a secondary track of the second conductive track, or when a microdrop of water generates an electrical circulation between the main track of the first conductive track and the main track of the second conductive track.

[20] - the secondary tracks of the first conductive track and the secondary tracks of the second conductive track are arranged alternately on the electronic card according to invention. That is to say that a secondary track of the comb formed by the first conductive track is placed between two consecutive teeth of the comb formed by the second conductive track, and a tooth of the comb formed by the second conductive track is placed between two. consecutive teeth of the comb formed by the first conductive track. In other words, the combs formed by the first conductive track and the second conductive track are nested one inside the other by their teeth arranged alternately towards one another. This makes it possible to increase the precision of the detection carried out by means of the invention. Indeed, each pair of teeth formed by a secondary track of the first conductive track and a secondary track of the second conductive track thus becomes a possible humidity detection site, thus increasing, in a small footprint, the size of the zone. humidity detection on the electronic card according to the invention.

[21] - the first conductive track and the second conductive track comprise a plurality of drains passing through the electronic card, the drains of the first conductive track being arranged alternately with the drains of the second conductive track. With reference to the general shape, previously mentioned, of the electronic card, each drain therefore extends over the entire thickness of the latter, from one main face of the latter to the other. Each drain forms, on one of the main faces of the electronic card according to the invention, a pin connected, on the opposite main face of the electronic card, to one or the other of the conductive tracks. We thus distinguish a first group of drains, connected to the first conductive track, and a second group of drains, connected to the second conductive track. In such a configuration, the desired humidity detection is achieved when a microdrop of water generates an electrical circulation between a pin of a drain of the first conductive track and a pin of a drain of the second conductive track. .

[22] - all the pins formed by the drains of the conductive tracks are located on the same main face of the electronic card. The humidity detection is therefore carried out on the face of the electronic card on which the aforementioned pins are placed.

[23] - a first set of pins formed by the previously defined drains is placed on a main face of the electronic card according to the invention, and a second set of pins formed by the previously defined drains is placed on the opposite main face of the electronic card according to the invention. Advantageously, the invention provides, for such a configuration, that the drains of each conductive track are placed on each main face of the electronic card. In other words, according to such a configuration, the two main faces of the electronic card can be used to achieve the desired humidity detection. This makes it possible to increase the sensitivity of such detection.

[24] - the first conductive track is substantially rectilinear, and the second conductive track substantially forms a U between the branches of which the first conductive track is inserted. According to an alternative embodiment, the second conductive track is substantially rectilinear, and the first conductive track substantially forms a U between the branches of which the second conductive track is inserted. Such configurations make it possible to increase the size of the detection zone in a small footprint. [25] - the humidity detection device is electrically connected between the previously mentioned microcontroller and an electrical supply point of the motor vehicle, and the humidity detection device is electrically connected to the terminals of a first resistor itself. even connected between the microcontroller and the aforementioned power supply point. For example, the humidity detection device is electrically connected between the microcontroller and a point from which an electric motor for driving the fan in question is supplied. The first resistor has, for example, the function of normalizing the voltage measured by the microcontroller at the terminals of the humidity detection device, that is to say of assigning a predefined value to this voltage. According to one example, the first resistor has a value of the order of a few kiloohms, for example of the order of 6 to 12 kiloohms. The humidity detection device is thus electrically connected in parallel with the portion of the electrical circuit formed by the microcontroller, the first resistor and the supply point. In the presence of humidity, the first resistor is electrically short-circuited, and the voltage measured by the microcontroller is lower than the voltage measured in the absence of moisture.

[26] - the humidity detection device is electrically connected between the microcontroller and a power point of an element of the vehicle, and the humidity detection device is electrically connected in series with a first resistor itself electrically connected between the microcontroller and the aforementioned power point. The humidity detection device is therefore here electrically connected in series with the microcontroller, the first resistor and the aforementioned electrical supply point. In the absence of humidity, no voltage is read by the microcontroller, no electrical contact existing between the first conductive track and the second conductive track of the humidity detection device. In the presence of moisture, a voltage can be read by the microcontroller. The humidity detection device therefore acts here as a switch.

[27] - the humidity detection device is electrically connected between the microcontroller and a power supply point of an element of the vehicle, and the electronic card according to the invention comprises a second resistor itself connected between the control device. humidity detection and microcontroller. According to one example, the second resistor has a value of the order of a few tens of kiloohms, for example of the order of 70 to 90 kiloohms. In the case of a previously described parallel connection of the humidity detection device, the second resistor is advantageously placed in series with the humidity detection device, across the first resistance defined above. In other words, in this case, the humidity detection device and the second resistor form a portion of the circuit electrically connected in parallel across the terminals of the first resistor defined above. In the presence of humidity, the voltage measured by the microcontroller then takes into account the first resistance and the second resistance.

[28] The invention, as it has just been described, therefore makes it possible to carry out, by simple and inexpensive means, a humidity detection within a housing in which a unit is housed. supply and control of a fan placed on the front of a motor vehicle. The invention therefore achieves the goal it had set for itself. [29] The invention also extends to an electronic unit configured to control an electric motor of a front face fan of a motor vehicle, characterized in that it comprises a housing delimiting an interior volume in which is received an electronic card as described above. Advantageously, such a case is waterproof.

[30] According to one aspect of the invention, such a housing comprises at least one humidity collection zone, and the humidity detection device of the electronic card according to the invention extends at least partly in the moisture collection area of this enclosure. The moisture collection area of the housing is an area in which moisture preferentially accumulates. According to one example, the humidity collection zone can be a low point of the housing, in which the humidity will preferably accumulate by gravity. According to another example, the humidity collection zone can be a cold point of the case in which the humidity will preferably accumulate by condensation. According to other examples, the moisture collection area may be an area preferentially subject to being exposed to moisture, such as, for example, a seal or a partition passage. According to various examples, the first conductive track and the second conductive track of the humidity detection device extend partially or entirely in the humidity collection zone of the housing.

[31] In order to promote such a configuration in a small footprint, the electronic card according to the invention advantageously comprises a protuberance on which are arranged, partially or entirely, the first conductive track and the second conductive track, this protuberance being placed in the aforementioned humidity collection area.

[32] The invention finally extends to a motor-driven front face fan of a motor vehicle, comprising at least one electric motor whose speed of rotation is governed by an electronic unit such as has just been described. , the motor-fan comprising a propeller rotated by the electric motor.

[33] Other features, details and advantages of the invention will emerge more clearly from the following description and from the drawings, among which:

[34] [Fig 1] Figure 1 is a schematic view of an electronic card according to a first embodiment of the invention,

[35] [Fig 2] FIG. 2 is a schematic view of an electronic card according to a second embodiment of the invention,

[36] [Fig 3] FIG. 3 is a schematic view of a first example of an electrical connection of the humidity detection device according to the invention on an electronic card as illustrated in FIG. 1 or in FIG. 2,

[37] [Fig 4] FIG. 4 is a schematic view of a second example of an electrical connection of a humidity detection device according to the invention on an electronic card as illustrated by FIG. 1 or figure 2, [38] [Fig 5] and Figure 5 is a schematic sectional view of a fan motor according to the invention.

[39] It should first of all be noted that if the figures set out the invention in detail for its implementation, they can of course be used to better define the invention if necessary. It should also be noted that, in all of the figures, elements that are similar and / or fulfill the same function are indicated by the same reference mark.

[40] With reference to the foregoing, FIG. 1 schematically illustrates a first main face 15 of an electronic card 1 according to the invention, the electronic card 1 comprising a second main face 16, not visible in FIG. 1, substantially parallel to the first main face 15, opposite to the latter. The first main face 15 and the second main face 16 of the electronic card 1 are separated from one another by a small thickness compared to the dimensions of the main faces 15, 16.

[41] The electronic card 1 is therefore in a generally substantially parallelepipedal shape. As shown in FIG. 1, the first main face 15 of the electronic card 1 comprises a first substantially rectangular part 151 and a second substantially rectangular part 152 which extends in the extension of an edge of the aforementioned first part 151. More precisely, an elongation dimension L2 of an edge 152a of the aforementioned second part 152 is less than an elongation dimension L1 of an edge 151a of the first part 151, substantially parallel to the aforementioned edge 152a, edge 151a to from which extends the second part 152 previously mentioned.

[42] In other words, as shown in Figure 1, the electronic card 1 comprises a first part 10 substantially parallelepiped and a second part 11 substantially parallelepiped which protrudes from the first part 10, so that 'at least one dimension of elongation L2 of the second part 11 is less than a dimension L1 of elongation L1 of the first part 10 measured parallel to the direction of elongation L2.

[43] Advantageously, the electronic card 1 is received in an interior volume 60 delimited by a sealed box 6, the interior volume 60 and the sealed box 6 are schematically mentioned in FIG. 1 and shown in FIG. 5.

[44] Referring to Figure 1, the electronic card 1 comprises in particular a microcontroller 2 configured to govern the operation of a motor of a fan of a motor vehicle, for example a fan placed on the front face of such vehicle and intended to generate an air flow passing through at least one heat exchanger. The electronic card 1 according to the invention advantageously comprises a set of electronic components not shown in the figure, configured for controlling the operation of the aforementioned motor.

[45] According to the invention, the electronic card 1 comprises a humidity detection device 100 which comprises in particular a first conductive track 3 electrically connected to the microcontroller 2 and a second conductive track 4 electrically connected to the microcontroller 2. With reference to FIG. 1, the first conductive track 3 and the second conductive track 4 are printed on the first main face 15 previously defined.

[46] According to the invention, the first conductive track 3 is configured to be brought to a first electrical potential 300, and the second conductive track 4 is configured to be brought to an electrical potential 400, different from the first electrical potential 300.

[47] According to the embodiment more particularly illustrated by Figure 1, the first conductive track 3 comprises a main track 30 which extends from the microcontroller 2, and a plurality of secondary tracks 31 which extend from of the main track 30, substantially perpendicular to the latter. Similarly, the second conductive track 4 comprises a main track 40 and a plurality of secondary tracks 41 which extend from the main track 40, substantially perpendicular to the latter. In other words, according to the exemplary embodiment illustrated by FIG. 1, the first conductive track 3 and the second conductive track 4 each form a comb, the teeth of which consist of the secondary tracks 31, 41, defined above.

[48] According to one example, the main tracks 30, 40, of the first conductive track 3 and of the second conductive track 4 are separated from each other by a maximum distance of the order of 1 millimeter. According to an advantageous example, the secondary tracks 31, 41 each have a length substantially comprised between 2 and 100 millimeters, preferably 20 millimeters, and they are separated from each other by a distance comprised between 0.1 and 2 millimeters, preferably 0.7 millimeters.

[49] Referring to Figure 1, part of the main tracks 30, 40, above, extends in the first part 10 of the electronic card 1, and the part of the conductive tracks 3, 4, on which are arranged the secondary tracks 31, 41, previously defined, extend in the second part 11 of the electronic card 1, that is to say in the protuberance formed from the first part 10 of the electronic card 1.

[50] According to the invention, the humidity detection device 100 is exposed to the interior atmosphere of the housing 6 previously mentioned, in particular to the humidity possibly contained in the interior volume 60 defined above. More precisely, the invention provides that the conductive tracks 3, 4 are exposed to the humidity contained in the interior volume 60 of the housing 6. For this purpose, the conductive tracks 3, 4 are, for example, devoid of varnish. protector which covers other connection tracks, not shown in FIG. 1, printed on electronic card 1.

[51] In the absence of humidity in the internal atmosphere of the housing 6, it follows from the above that there is no electrical contact between the first conductive track 3 and the second conductive track 4. A voltage 700 measured at the terminals of the humidity detection device 100 therefore has a reference value, a function of the first potential 300 and of the second potential 400 defined above. [52] In the presence of humidity, microdrops or drops of water form within the aforementioned interior volume 60. When one of these microdrops or drops extends simultaneously over part of the first conductive track 3 and of the second conductive track 4, it generates an electrical circulation between these two conductive tracks. The voltage 700 measured at the terminals of the humidity detection device 100 then varies with respect to the aforementioned reference value. According to one aspect of the invention, the microcontroller 2 is configured to measure the voltage 700 previously defined and to compare it with the reference value previously defined. The microcontroller 2 is also advantageously configured to generate a signal representative of the result of this comparison. According to various examples, this signal may be an information signal intended for the vehicle, or a control signal for a component of the vehicle in order to implement protective measures for the electronic card 1 (for example, by stopping '' a fan motor controlled by the electronic card 1).

[53] According to one example, the previously defined reference value can be fixed, previously determined in an arbitrary manner, for example a supply voltage of the microcontroller 2. The humidity detection will then be confirmed as soon as the voltage 700 measured at the terminals of the humidity detection device by the microcontroller 2 or the difference between a voltage 700 measured at the terminals of the detection device 100 and this reference value will exceed a threshold value defined beforehand. According to another example, the aforementioned reference value can be determined as a function of a parameter of the vehicle, for example the reference value can be defined as a nominal power supply value of the microcontroller 2, itself a function of a voltage power supply from a battery of the latter. In the latter case, it should be noted that the confirmation of humidity detection will take into account a specific parameter of the vehicle, thus making it possible to avoid any risk of inappropriate detection following a normal drift, over time, of the chosen reference value.

[54] According to the configuration more particularly illustrated in FIG. 1, the first conductive track 3 and the second conductive track 4 are arranged on the first main face 15 of the electronic card 1 such that the secondary tracks 31, 41, previously defined, are placed alternately. More precisely, according to this example, the secondary tracks 31 of the first conductive track 3 are directed towards the main track 40 of the second conductive track 4, and the secondary tracks 41 of the second conductive track 4 are directed towards the main track 30 of the first conductive track 3. In addition, a secondary track 31 is placed between two secondary tracks 41, and a secondary track 41 is placed between two secondary tracks 31. This applies to all the secondary tracks 31, 41 of the conductive tracks 3 , 4, with the exception of a secondary track located at the end of each of the combs respectively formed by the conductive tracks 3, 4. In other words, according to the example illustrated in FIG. 1, the conductive tracks 3, 4, form combs nested one inside the other by their teeth formed by the secondary tracks 31, 41.

[55] In such a configuration, humidity detection occurs as soon as a microdrop of water simultaneously extends over the main track 30 of the first track. conductive 3 and on the main track 40 of the second conductive track 4, and / or when a microdrop of water extends simultaneously over one of the secondary tracks 31 and one of the secondary tracks 41 defined above. The comb-shaped configuration of the conductive tracks 3, 4, illustrated by FIG. 1, then makes it possible to multiply the detection sites, by multiplying the areas in the vicinity of the first conductive track 3 with the second conductive track 4. In other words , it can be considered that such a comb configuration increases a specific detection surface defined by the main tracks 30, 40, and by the secondary tracks 31, 41, previously defined.

[56] This makes it possible in particular to increase the precision of the detection performed. Indeed, by multiplying the detection sites, and by arranging the conductive tracks 3, 4, as close as possible to one another, such a configuration makes it possible to reduce the minimum size of a microdrop which can generate an electrical circulation between the first conductive track 3 and the second conductive track 4, thus lowering the humidity detection threshold.

[57] FIG. 2 illustrates a second embodiment of an electronic card 1 according to the invention. In FIG. 2, we find the electronic card 1, the housing 6 and its internal volume 60 schematically represented, as well as the various parts, previously described, of the electronic card 1.

[58] Referring to Figure 2, the first conductive track 3 and the second conductive track 4 comprise a main track, respectively 30, 40, and a plurality of drains, respectively 32, 42, which pass through the thickness of the card electronic 1. More precisely, each drain 32, 42, extends from the first main face 15, previously defined, of the electronic card 1, to the second main face 16, previously defined, not visible in FIG. 2, of the electronic card 1. More precisely still, according to this second exemplary embodiment of the invention, each drain 32, 42 forms, on one of the main faces of the electronic card 1, a pin, and it is connected, on the face main opposite of the electronic card 1, to one of the conductive tracks, 3 or 4. We thus distinguish a first group of drains 32 connected to the main track 30 of the first conductive track 3, and a second group of connected drains 42 to the main runway 40 of the second th conductive track 4.

[59] According to such a configuration, the detection of humidity is carried out when a microdrop of water extends simultaneously on a pin of a drain of the first group of drains 32 and on a pin of a drain of the. second group of drains 42.

[60] As in the first embodiment illustrated in Figure 1, the parts of the conductive tracks 3, 4, on which are arranged the drains, respectively 32, 42, are in the second part 11 of the electronic card 1.

[61] According to the exemplary embodiment more particularly illustrated by FIG. 2, all the pins formed by the drains 32, 42 are located on the first main face 15 of the electronic card 1. Furthermore, according to this example, the part of the first conductive track 3 carrying the drains 32 is substantially rectilinear, and the part of the second conductive track 4 carrying the drains 42 substantially forms a U between the branches of which is inserted the part of the first conductive track 3 carrying the drains 32. Alternatively, the part of the second conductive track 4 carrying the drains 42 may be substantially rectilinear, and the part of the first conductive track 3 carrying the drains 32 may form substantially a U between the branches of which is inserted the part of the second conductive track 4 carrying the drains 42.

[62] It should be understood here that, according to this exemplary embodiment, the drains 32 of the first conductive track 3 are connected to each other and to the main track 30 of the first conductive track 3 on the second main face 16 of the electronic card. 1, not visible in FIG. 2, and the drains 42 of the second conductive track 4 are connected to each other and to the main track 40 of the second conductive track 4 on the aforementioned second main face 16.

[63] According to different variants, all or part of the pins formed by the drains 32, 42, can be placed on one or the other of the main faces 15, 16, of the electronic card 1. Thus, a first set of pins formed by drains from the first group of drains 32 and drains from the second group of drains 42 can be placed on the first main face 15 of the electronic card 1, and a second set of pins formed by drains from the first group of drains 32 and the drains of the second group of drains 42 can be placed on the second main face 16 of the electronic card 1. Such a configuration makes it possible to detect humidity on each of the main faces of the electronic card, increasing the sensitivity of detection carried out.

[64] FIG. 3 illustrates a first example of an electrical connection of a humidity detection device 100 such as has just been described on an electronic card 1 as illustrated by FIG. 1 or by the figure 2.

[65] In FIG. 3 are diagrammatically represented the electronic card 1, the microcontroller 2 and the humidity detection device 100. FIG. 3 also shows a point of supply 5 of a component of the vehicle by the microcontroller 2, as well as a first resistor 200 placed between the microcontroller 2 and the supply point 5. FIG. 3 finally shows a connection point 7 between the microcontroller 2 and the portion of the circuit formed by the first resistor 200 and the point of power supply 5 above. According to one example, the first resistor 200 has a value of a few kiloohms, for example about 10 kiloohms. The feed point 5 can, for example, be a current feed point of an electric motor for driving a propeller of a front face motor fan of the motor vehicle in question.

[66] According to the first example illustrated in FIG. 3, the humidity detection device 100 is electrically connected to the terminals of the aforementioned first resistor 200. The humidity detection device 100 is therefore, according to this example, connected in parallel with the portion of the electrical circuit formed by the microcontroller 2, the first resistor 200 and the supply point 5. In the absence of humidity. , the voltage 700 measured between the connection point 7 and the supply point 5 is defined by the first resistor 200. In the presence of humidity, that is to say when an electrical contact is established between the first conductive track 3 and the second conductive track 4 of the humidity detection device 100, the voltage 700 measured by the microcontroller 2 between the connection point 7 and the aforementioned supply point 5 is defined by the detection device humidity 100. In other words, in the presence of humidity, the first resistor 200 is electrically short-circuited: the voltage 700 measured between the connection point 7 and the supply point 5 is therefore, in this case , the voltage across the humidity detection device 100, and it is lower than the voltage 700 measured in the absence of humidity.

[67] According to one aspect of the invention, a second resistor 250 can be placed between the humidity detection device 100 and the connection point 7 defined above. According to one example, the second resistor 250 has a value of the order of a few tens of kiloohms, for example between 80 and 90 kiloohms.

[68] According to the example more particularly illustrated by FIG. 3, the second resistor 250 is placed in series with the humidity detection device 100 and it forms, with the latter, an electrical circuit portion connected in parallel with the circuit portion formed by the microcontroller 2, the connection point 7, the first resistor 200 and the supply point 5. The second resistor 250 has, for example, the function of normalizing the voltage 700 measured by the microcontroller at the terminals of the humidity detection device 100 in the presence of humidity, that is to say to assign a predefined value to this voltage.

[69] FIG. 4 illustrates a second example of an electrical connection of a humidity detection device 100 as described above on an electronic card 1 as illustrated by FIG. 1 or by FIG. 2.

[70] We find in Figure 4 the microcontroller 2, the connection point 7, the supply point 5, and the first resistor 200 previously defined.

[71] According to this exemplary embodiment, the humidity detection device 100 is electrically connected in series with the microcontroller and the first resistor 200. More precisely, the humidity detection device 100 is here electrically connected between the first resistor. 200 and the connection point 7 of the microcontroller 2. According to different variants, a second resistor 250 as described above can be inserted in series between the humidity detection device 100 and the aforementioned connection point 7.

[72] As mentioned above, in the absence of humidity, there is no electrical contact between the first conductive track 3 and the second conductive track 4 of the humidity detection device 100. No voltage 700 does not exist. can therefore theoretically be measured by the microcontroller 2 between the connection point 7 and the supply point 5. In the presence of humidity, an electrical contact is established between the first conductive track and the second conductive track. The voltage 700 measured by the microcontroller 2 between the connection point 7 and the supply point 5 then takes a value which is a function of the value of the first resistor 200 and of the value of the second resistor 250. The detection device of humidity 100 thus acts, according to this configuration, like a switch. [73] Whatever the example chosen, it emerges from the foregoing that the invention allows, by the implementation of simple and inexpensive means, and by means of simple electrical connections, to achieve humidity detection. in an environment in which an electronic card such as that described above is placed.

[74] As previously mentioned, the invention finds a preferred application to a motor-fan assembly placed on the front face of a motor vehicle.

[75] FIG. 5 schematically illustrates such a motorized fan 600, in section along an axis of rotation X of the latter.

[76] With reference to FIG. 5, such a motor-fan 600 comprises an electric motor 500, for example formed of a rotor 510 schematically mentioned in FIG. 5, movable in rotation about an axis X, and of a stator 520 mounted statically with respect to the rotor 510. The motorized fan 600 also comprises a propeller 650 driven in rotation by the electric motor 500. Advantageously, the propeller 650 is mounted integral with the aforementioned rotor 510, in such a way that it is driven in rotation around the axis X previously defined by the rotation of the rotor 510 around this same axis of rotation.

[77] The motor fan 600 also comprises an electronic power supply and control unit 8 of the electric motor 500. Advantageously, the electric motor 500 and its electronic power supply and control unit 8 are interconnected by a device for 'interconnection not shown in Figure 5.

[78] In a motorized fan 600 according to the invention, the electronic power supply and control unit 8 comprises a housing 6 delimiting an internal volume 60 in which is received an electronic card 1 as described above. Taking into account the environment in which the electronic power supply and control unit 8 is placed, the housing 6 is advantageously sealed. However, moisture may be present in the interior volume 60 of the housing 6, for example due to imperfect sealing, or following condensation phenomena resulting from thermal differences within components of the electronic card 1.

[79] According to the invention, the housing 6 comprises a collection zone 61 of such humidity, that is to say a zone in which the humidity possibly present in the interior volume 60 is preferably accumulated. It is necessary to distinguish here the humidity possibly contained in small quantity or in the state of traces within the aforementioned interior volume 60, and the humidity contained in the ambient atmosphere in which the housing 6 of the electronic unit of power supply and control 8 is submerged due to the location of the motor-fan 600 on the front face of the vehicle in question.

[80] According to a first exemplary embodiment, the collection zone 61 can be a low point of the housing 6, that is to say a region of the interior volume 60 towards which the humidity contained in this volume will preferably be conveyed by gravity. According to another example, the collection zone 61 can be a region of the housing 6 located near a seal or a partition passage, more generally a region more particularly subject to exposure to moisture due to lack of sealing. According to other exemplary embodiments, the collection zone 61 may be a cooler region of the interior volume 60, more particularly subject to being exposed to humidity by condensation.

[81] In all cases, the invention provides that the electronic card 1 is placed in the housing 6 previously defined such that the humidity detection device 100 is, at least in part, located in the zone of collection 61 cited above. The particular conformation of the electronic card 1, more particularly illustrated by FIGS. 1 and 2, finds here an additional advantage, in that it allows, on the one hand, that the zone dedicated to the humidity detection device 100 on the electronic card 1 is separated from the installation areas of the other components that this card carries and, on the other hand, in that it makes it possible to reduce the space required for this humidity detection within the interior volume of the box 6. For example, the collection zone 61 can be in the form of a notch produced in the housing 6, a notch in which the protuberance formed by the second part of the electronic card 1 can be plugged in.

[82] The invention, as it has just been described, achieves the goals it had set itself and allows, by simple and inexpensive means, to achieve efficient and reproducible detection of humidity. present in a sealed casing of an electronic power supply and control unit of a motor vehicle front face fan.

[83] The invention cannot however be limited to the means and configurations described and illustrated, and it also applies to all equivalent means or configurations and to any combination of such means. In particular, if the invention has been described and illustrated here in the case where the humidity detection is based on a voltage measurement, the invention applies to the case the humidity detection is carried out by means of a measurement of an electric current flowing in the humidity detection device, or by means of a measurement of any electrical quantity that can be affected by the presence of a microdrop extending between the first conductive track and the second conductive track described in this document (capacitance measurement, for example).

[84] In addition, if the invention has been described and illustrated here in the case where the various conductive tracks described are substantially rectilinear, it applies to any geometry of such conductive tracks, insofar as the latter have the characteristics and specificities described and illustrated in this document.

Claims

1. Electronic card (1) configured to control an electric motor (500) of a motor-fan (600) on the front face of a motor vehicle, the electronic card (1) comprising at least one microcontroller (2) and one. plurality of conductive tracks, characterized in that the electronic card (1) comprises a humidity detection device (100).

2. Electronic card (1) according to the preceding claim, characterized in that the humidity detection device (100) comprises a first conductive track (3) configured to be brought to a first electrical potential (300) and a second track conductor (4) configured to be brought to a second electric potential (400), different from the first electric potential (300), the first conductive track (3) and the second conductive track (4) being printed on the electronic card (1) .

3. Electronic card (1) according to the preceding claim, characterized in that the first conductive track (3) and the second conductive track (4) are separated by a distance between 0.1 and 2 millimeters.

4. Electronic card (1) according to the preceding claim, characterized in that the first conductive track (3) and the second conductive track (4) each comprise a main track (30, 40) and a plurality of secondary tracks (31, 41) which extend from the main track (30, 40).

5. Electronic card (1) according to the preceding claim, characterized in that the secondary tracks (31) of the first conductive track (3) and the secondary tracks (41) of the second conductive track (4) are arranged alternately on the electronic card (1).

6. Electronic card (1) according to claim 3, characterized in that the first conductive track (3) and the second conductive track (4) comprise a plurality of drains (32, 42) passing through the electronic card (1), the drains (32) of the first conductive track (3) being arranged alternately with the drains (42) of the second conductive track (4).

7. Electronic card (1) according to any one of the preceding claims, wherein the humidity detection device (100) is electrically connected between the microcontroller (2) and a power point (5) of an element. of the motor vehicle, and in which the humidity detection device (100) is electrically connected to the terminals of a first resistor (200) itself connected between the microcontroller (2) and the power supply point (5).

8. Electronic card (1) according to any one of claims 1 to 5, wherein the humidity detection device (100) is electrically connected between the microcontroller (2) and a power point (5) of an element of the motor vehicle, and in which the humidity detection device (100) is electrically connected in series with a first resistor (200) itself connected between the microcontroller (2) and the power point (5) .

9. Electronic card (1) according to any one of the preceding claims, wherein the humidity detection device (100) is electrically connected between the microcontroller (2) and a power point (5) of an element. of the motor vehicle, characterized in that it comprises a second resistor (250) itself connected between the humidity detection device (100) and the microcontroller (2).

10. Electronic unit (8) configured to control an electric motor (500) of a motor-driven front face fan of a motor vehicle, characterized in that it comprises a housing (6) delimiting an interior volume (60) wherein an electronic card (1) according to any one of the preceding claims is received.

11. Electronic unit (8) according to the preceding claim, wherein the interior volume (60) of the housing (6) comprises at least one humidity collection zone (61), and in that the humidity detection device (100) of the electronic card (1) extends at least partly in the humidity collection zone (61).

12. Motorized fan (600) of the front face of a motor vehicle comprising at least one electric motor (500), the speed of rotation of which is placed under the control of an electronic unit (8) according to one of claims 10. or 11, the motor-fan (600) comprising a propeller (650) rotated by the electric motor (500).