Thermode device for telematics control unit of a vehicle

Abstract

The invention relates to a thermal diode device comprising an electronic unit (1) to be cooled, a heat spreading medium (2), a temperature sensor (4) for measuring the temperature of the heat spreading medium (2) and an actuator configured to thermally disconnect the electronic unit from the heat spreading medium if the temperature of the heat spreading medium is higher than a reference temperature, thereby inhibiting any heat transfer between the heat spreading medium and the electronic unit, and to thermally connect the electronic unit to the heat spreading medium if the temperature of the heat spreading medium is lower than the reference temperature, so as to allow conductive heat transfer between the electronic unit and the heat spreading medium.

Description

Technical Field

[0001] This invention relates to a device for automatically coupling and decoupling electronic units relative to a medium that ensures conductive heat dissipation (in other words, ensures the function of a heat sink). The device is referred to in particular hereinafter as a "thermal diode" because it is configured to allow heat transfer only in a single direction (i.e., from the electronic unit to the heat dissipation medium).

[0002] More specifically, one application of the invention relates to an electronic module, such as a telematics control unit (also known as a TCU), mounted near the roof of a vehicle, the roof corresponding to the medium, which ensures a heat dissipation function to dissipate heat emitted by the telematics control unit. Background Technology

[0003] As is well known, the latest developments in the automotive field involve telematics control units and their integration with so-called "smart" antennas.

[0004] These antennas are typically mounted on the roof of the vehicle to optimize their gain when transmitting and receiving signals, and thus facilitate the vehicle's external connectivity.

[0005] In this case, the telematics control unit coupled to at least one antenna is usually also located on the roof of the vehicle to be close to the antenna and thus avoid some inconveniences that may be related to the wiring between the telematics control unit (e.g., located in the dashboard) and the antenna located on the roof.

[0006] Therefore, smart antenna modules are typically located directly below the roof, or at least close to the exterior surface of the vehicle.

[0007] From a connectivity perspective, this positioning is quite advantageous, but it also has two main drawbacks: First, space is limited because it is usually located in the roof lining of the passenger compartment, which imposes considerable constraints on the size of the telematics control unit; second, because the telematics control unit is close to the roof, it may be exposed to high temperatures when the vehicle is stationary and exposed to sunlight (especially in areas of the world with strong solar radiation).

[0008] However, it is necessary to dissipate the heat generated by the telematics control unit. In fact, as is well known, electronic components (such as those present in the telematics control unit) have a maximum operating temperature, above which they may degrade, for example, leading to a shortened lifespan or, especially in the case of non-volatile memory, loss of information.

[0009] As mentioned above, when the telematics control unit is located on the roof, it is difficult to cool it using an active convection system (in other words, a fan), especially due to space constraints.

[0010] When the temperature on the roof is low, the roof can be advantageously used as a very good radiator. However, in the special circumstances described above, the telematics control unit should be isolated from the roof as much as possible, and efforts should be made to dissipate its heat into the interior of the passenger compartment.

[0011] Therefore, there is a need for a device that can thermally couple and decouple a telematics control unit or more generally any electronic unit from a roof or more generally a medium capable of performing heat dissipation while being easily heated under certain specific conditions, making it necessary to isolate it from the electronic unit to be cooled.

[0012] Therefore, the present invention relates to a device called a "thermal diode" that enables automatic thermal coupling and decoupling of electronic units relative to the heat dissipation medium based on the temperature of the heat dissipation medium. Summary of the Invention

[0013] More specifically, the present invention relates to a thermal diode device comprising an electronic unit to be cooled, a heat dissipation medium, a temperature sensor for measuring the temperature of the heat dissipation medium, and an actuator configured to: thermally disconnect the electronic unit from the heat dissipation medium if the temperature of the heat dissipation medium is higher than a reference temperature, thereby suppressing any conductive heat transfer between the heat dissipation medium and the electronic unit; and conductively thermally connect the electronic unit to the heat dissipation medium if the temperature of the heat dissipation medium is lower than the reference temperature, thereby allowing conductive heat transfer between the electronic unit and the heat dissipation medium.

[0014] Thanks to this invention, conductive heat transfer can be allowed in only one direction (from the electronic unit to be cooled to the heat dissipation medium), while conductive heat transfer in the other direction (when the heat dissipation medium is hotter than the electronic unit) is suppressed.

[0015] According to one embodiment, the device includes a temperature sensor for the electronic unit, with the reference temperature being the temperature of the electronic unit.

[0016] Advantageously, the reference temperature is equal to the temperature of the electronic unit multiplied by a weighting factor adapted to take into account the heat dissipation specific to the actuator.

[0017] According to one embodiment, the electronic unit includes a thermal pad (34) that ensures a thermal interface between the electronic unit and the heat dissipation medium when the electronic unit and the heat dissipation medium are in physical contact.

[0018] According to one embodiment, the actuator includes a spring connected between a heat dissipation medium and a thermal pad of an electronic unit, and an electromagnet attached to the heat dissipation medium, wherein the spring is used to apply a repulsive force on the thermal pad of the electronic unit, repelling the electronic unit away from the heat dissipation medium, and when powered, the electromagnet is used to apply an attractive force on the thermal pad of the electronic unit, attracting it toward the heat dissipation medium.

[0019] According to one embodiment, the thermal pad has mechanical flexibility adapted such that, under the action of a repulsive force, in the absence of an attractive force exerted by an electromagnet, the thermal pad bends to separate from the heat dissipation medium, and under the action of an attractive force having a strength greater than the repulsive force, the thermal pad extends to contact the heat dissipation medium.

[0020] According to one embodiment, the device includes a control module configured to:

[0021] If the temperature of the heat dissipation medium is lower than the reference temperature, the electromagnet is activated, causing it to apply an attractive force to the electronic unit that is stronger than the repulsive force applied by the spring. This thermally couples the electronic unit and the heat dissipation medium by bringing them into physical contact via the thermal pad.

[0022] If the temperature of the heat dissipation medium is higher than the reference temperature, the electromagnet is deactivated, so that the electromagnet does not exert any attractive force on the electronic unit. Since there is air between the electronic unit and the heat dissipation medium, the repulsive force applied by the spring to the thermal pad of the electronic unit allows the electronic unit and the heat dissipation medium to be thermally decoupled.

[0023] According to one embodiment, the temperature sensor on the roof is a thermocouple.

[0024] Advantageously, the electronic unit is the vehicle's telematics control unit, while the heat dissipation medium is the roof.

[0025] The present invention also relates to a motor vehicle including a passenger compartment having a roof, an antenna disposed on the roof, and a telematics processing control unit coupled to the antenna and disposed under the roof, the vehicle including a thermal diode device as briefly described above. Attached Figure Description

[0026] Other features and advantages of the invention will become more apparent from the following description. This description is purely illustrative and should be read with reference to the accompanying drawings, in which:

[0027] [ Figure 1 ]: Figure 1 An example of a thermal diode device according to the invention is shown, wherein the telematics control unit and the roof are conductively thermally coupled.

[0028] [ Figure 2 ]: Figure 2 An identical embodiment of the thermal diode device according to the invention is shown, wherein the telematics control unit and the roof are not conductively thermally coupled. Detailed Implementation

[0029] In the following text, reference is made primarily to the implementation of the invention in the context of a motor vehicle, wherein the device according to the invention allows for the automatic thermal coupling and decoupling of the telematics control unit relative to the roof.

[0030] However, the present invention is for other applications in which the electronic unit is arranged near a medium that, except under specific conditions where the medium is hotter than the electronic unit, can ensure heat dissipation.

[0031] refer to Figure 1 The diagram shows a telematics control unit 1 (also known as a TCU), positioned as close as possible to the antenna, particularly a so-called "smart" antenna. In the context of this invention, the telematics control unit 1 is an electrical unit that generates heat and should be cooled.

[0032] The assembly is located at point 2 on the vehicle roof: from this high point on the vehicle, the antenna is positioned optimally for transmitting and receiving signals. The telematics control unit is located immediately adjacent to the antenna.

[0033] During operation, the telematics control unit 1 generates heat, which must be dissipated. In fact, according to the first law of thermodynamics, all energy injected into a closed system is output as work or heat. In this case, the electrical energy injected into the telematics control unit 1 must be output at least partially as heat. This heat must be dissipated to prevent overheating and consequent degradation of the electronic components of the telematics control unit 1.

[0034] It is known that using the roof 2 to dissipate (particularly through conduction) the heat emitted by the telematics control unit 1 is very effective, provided that the temperature of the roof is lower than the temperature of the telematics control unit 1. Therefore, the roof 2 acts as a radiator and effectively dissipates the heat emitted by the telematics control unit 1.

[0035] However, as mentioned earlier, in certain situations, particularly (especially when parked) and with prolonged exposure to sunlight, especially in geographical areas with strong solar radiation (such as the Arabian Peninsula), the temperature of the roof 2 may exceed that of the telematics control unit 1, especially during operation. Typically, the temperature of the roof 2 can reach and exceed 80°C. Therefore, the roof 2 is hotter than the telematics control unit 1, and to prevent heat transfer from the roof 2 to the telematics control unit 1, it becomes desirable, or even necessary, to suppress any heat conduction between the telematics control unit 1 and the roof 2. This clearly contradicts the need to dissipate the heat emitted by the telematics control unit 1, and could even lead to the degradation of some of its electronic components by causing overheating, such as data loss in non-volatile memory, even when the system is not in operation.

[0036] like Figure 1 As shown, the device according to the invention ensures the function of the thermal diode, that is, it allows the coupling between the roof 2 and the telematics control unit 1 to be ensured, so that heat can only flow in one direction (i.e. from the telematics control unit 1 to the roof 2) by conduction.

[0037] In other words, thanks to the thermal diode device according to the invention, when the roof 2 is colder than the telematics control unit 1, the roof 2 is used as a radiator, and thus the heat emitted by the telematics control unit 1 can be dissipated. Conversely, thanks to the thermal diode device according to the invention, when the roof 2 is hotter than the telematics control unit 1, the telematics control unit 1 is thermally decoupled from the roof 2 to prevent any conductive heat transfer from the roof to the telematics control unit 1.

[0038] The thermal diode device according to the invention includes measuring devices 4 for measuring the temperature of the roof 2; these measuring devices 4 are, for example, thermocouples connected to the roof 2. Preferably, the thermal diode device has means for accessing the temperature of the telematics control unit 1, either using its own measuring devices or using a communication device that receives temperature information of the telematics control unit 1 measured by a third-party device.

[0039] Based on the temperature of the roof 2, the thermal diode device according to the present invention automatically thermally couples or decouples the remote information processing control unit 1 relative to the roof 2.

[0040] More precisely, if the temperature of the roof 2 is higher than the reference temperature, the thermal diode device according to the invention is configured to thermally decouple the telematics control unit 1 from the roof 2.

[0041] Conversely, if the temperature of the roof 2 is lower than the reference temperature, the thermal diode device according to the invention is configured to conductively thermally couple the telematics control unit 1 to the roof 2.

[0042] In other words, when the temperature of the roof 2 is lower than the reference temperature, the thermal diode device according to the present invention applies low thermal resistance between the roof 2 and the telematics control unit 1, while when the temperature of the roof 2 is higher than the reference temperature, the thermal diode device according to the present invention applies high thermal resistance between the roof 2 and the telematics control unit 1.

[0043] By default, that is, if the thermal diode device according to the invention is not functioning (in other words, not running or not powered), or if the temperature information of the roof 2 is unavailable, the thermal diode device according to the invention can be configured to thermally decouple the telematics control unit 1 from the roof 2.

[0044] According to one embodiment, the reference temperature is the temperature of the telematics control unit 1. Preferably, the reference temperature is the temperature of the telematics control unit 1 multiplied by a weighting factor adapted to account for the heat dissipation specific to the thermal diode device when the thermal diode device is in operation (for thermally decoupling the telematics control unit 1 from the roof 2). Alternatively, the reference temperature may be a predetermined threshold temperature.

[0045] Now refer to Figure 1 and 2 Provide a detailed description of an example of a thermal diode device and its operation.

[0046] As in Figure 1 and Figure 2 As shown above, the thermal diode device according to the present invention is an active device that includes a thermal pad 34 (also known as a "thermalpad") with very low thermal resistance integrated into the telematics control unit 1.

[0047] The spring 32 is configured to remove the heating pad 34 by applying a force (referred to as a repulsive force) to the heating pad 34. The spring 32 is made of, for example, an insulating material.

[0048] The electromagnet 31 arranged on the roof 2 is configured to counteract the slack of the spring 32 by applying an attractive force to the heating pad 34 and the telematics control unit 1.

[0049] like Figure 1 As shown, when the electromagnet 31 is activated (in other words, when powered), the thermal pad 34 is attracted to the electromagnet 31, compressing the spring 32 until a direct physical connection is established with the roof 2. The thermal pad 34, and therefore the telematics control unit 1, then come into thermal contact with the roof 2, and the total thermal resistance between the telematics control unit 1 and the roof 2 is low, as it corresponds only to the thermal resistance of the thermal pad 34. Therefore, efficient heat transfer between the telematics control unit 1 and the roof 2 is possible.

[0050] On the contrary, such as Figure 2 As shown, when the electromagnet 31 is not in use (in other words, when it is off), it does not exert any attraction on the heating pad 34 and the telematics control unit 1. Therefore, the spring 32 is configured to remove the heating pad 34 and thus the telematics control unit 1 from the roof 2.

[0051] Therefore, the total thermal resistance between the telematics control unit 1 and the roof 2 is high because it corresponds to the thermal resistance of the air that separates the heating pad 34 (and therefore the telematics control unit 1) from the roof 2, since there is no direct physical contact between the heating pad 34 and the roof 2.

[0052] Therefore, there is little or no conductive heat transfer between the roof 2 and the telematics control unit 1.

[0053] For this purpose, the thermal pad 34 is mechanically flexible, adapted such that under the repulsive force applied by the spring 32 and in the absence of sufficient attractive force applied by the electromagnet 31, the thermal pad 34 bends to separate from the heat dissipation medium 2, and conversely, under the attractive force applied by the electromagnet 31 (which has a higher strength than the repulsive force applied by the spring 32), the thermal pad 34 extends to contact the heat dissipation medium 2.

[0054] According to the present invention, the activation or deactivation of the electromagnet 31 is implemented based on the temperature of the roof 2. In other words, according to one embodiment, the thermal diode device according to the present invention includes a control module 33 that receives temperature information about the roof 2 from the thermocouple 4.

[0055] The temperature information of the roof 2 is transmitted to the control module 3. The control module 3 activates or deactivates the electromagnet 31 based on the temperature difference between the control unit 1 and the roof 2 according to the remote information processing.

[0056] The control module 3 of the thermal diode device according to the present invention is configured such that:

[0057] If the temperature of the roof 2 is higher than the reference temperature, the electromagnet 31 will not function, and the conductive heat transfer between the roof 2 and the telematics control unit 1 will be minimized.

[0058] If the temperature of the roof 2 is lower than the reference temperature, the electromagnet 31 will activate, and there will be conductive heat transfer between the telematics control unit 1 and the roof 2.

[0059] In other words, when the temperature of the roof 2 is higher than the reference temperature, the thermal diode device according to the invention ensures thermal decoupling between the telematics control unit 1 and the roof 2. When the temperature of the roof 2 is lower than the reference temperature, the thermal diode device according to the invention ensures thermal coupling between the telematics control unit 1 and the roof 2.

[0060] According to one embodiment, when the thermal diode device is not functioning or is not powered, the electromagnet 31 is deactivated, and the thermal pad 34 and therefore the telematics control unit 1 are not thermally connected to the roof 2.

Claims

1. A thermal diode device comprising a telematics control unit (1) of a vehicle to be cooled, a roof (2), a temperature sensor (4) for measuring the temperature of the roof (2), and an actuator, wherein the telematics control unit is disposed under the roof, and the actuator is configured to: thermally disconnect the telematics control unit from the roof if the temperature of the roof is higher than a reference temperature, thereby suppressing any conductive heat transfer between the roof and the telematics control unit; and conductively thermally connect the telematics control unit to the roof if the temperature of the roof is lower than the reference temperature, thereby allowing conductive heat transfer between the telematics control unit and the roof, wherein the telematics control unit (1) includes an associated thermal pad (34) that provides a thermal interface between the telematics control unit (1) and the roof (2) when the telematics control unit (1) and the roof are in physical contact, characterized in that, The actuator includes a spring (32) connected between the roof (2) and the thermal pad (34) of the telematics control unit (1) and an electromagnet (31) attached to the roof (2), wherein the spring (32) applies a repulsive force to the thermal pad (34) of the telematics control unit (1) to push the telematics control unit (1) away from the roof (2), and wherein when power is supplied to the electromagnet (31), the electromagnet (31) applies an attractive force to the thermal pad (34) of the telematics control unit (1) to attract it toward the roof (2).

2. The apparatus according to claim 1, comprising a temperature sensor of the remote information processing control unit, wherein the reference temperature is the temperature of the remote information processing control unit (1).

3. The apparatus according to claim 1, wherein the reference temperature is equal to the temperature of the remote information processing control unit (1) multiplied by a weighting factor, the weighting factor being adapted to take into account the heat dissipation specific to the actuator.

4. The apparatus according to any one of the preceding claims, wherein, The heating pad (34) has mechanical flexibility adapted such that, under the action of a repulsive force, in the absence of an attractive force exerted by the electromagnet (31), the heating pad (34) bends to separate from the roof (2), and under the action of an attractive force having a strength greater than the repulsive force, the heating pad (34) extends to contact the roof (2).

5. The apparatus according to claim 4, further comprising a control module (33), the control module (33) being configured to: If the temperature of the roof (2) is lower than the reference temperature, the electromagnet (31) is activated, causing the electromagnet (31) to exert an attractive force on the telematics control unit (1) with a strength greater than the repulsive force exerted by the spring (32), thereby conductively thermally coupling the telematics control unit (1) and the roof (2) through physical contact via the thermal pad (34). If the temperature of the roof (2) is higher than the reference temperature, the electromagnet (31) is deactivated, causing the electromagnet (31) to not exert any attractive force on the telematics control unit (1). Since there is air between the telematics control unit (1) and the roof (2), the repulsive force exerted by the spring (32) on the thermal pad of the telematics control unit (1) allows the conductive thermal coupling between the telematics control unit (1) and the roof (2) to be broken.

6. The apparatus according to any one of claims 1 to 3, wherein, The temperature sensor (4) on the roof is a thermocouple.

7. A motor vehicle comprising a passenger compartment having a roof, an antenna disposed on the roof, and a telematics processing control unit coupled to the antenna and disposed under the roof, the vehicle including a thermal diode device according to any one of the preceding claims.

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