System and method for controlling the temperature of a multilayer composite structure

Abstract

The invention relates to a system (10) comprising a multilayer composite structure (1) with a single-layer or multilayer top layer (2), a heating layer (3) formed from a first electrically conductive layer (3), and at least one temperature sensor (9), wherein a first sensor signal (S1) of the temperature sensor (9) can be transmitted to an electronic computing device (4) connected to the temperature sensor (9). The electronic computing device (4) is configured to evaluate the second sensor signal (S2) of the proximity sensor (5) and to detect an impending contact with the composite structure (1), wherein the electronic computing device (4), after detecting an impending contact and exceeding a defined threshold value (S1), max ) of the sensor signal (S1) of the temperature sensor (9) is designed to output a control signal (S3) and to reduce or interrupt the heating power of the heating layer (3).

Description

[0001] The invention relates to a system comprising a multilayer composite structure with a single-layer or multilayer top layer, a heating layer formed from a first electrically conductive layer, and at least one temperature sensor. A first sensor signal from the temperature sensor can be forwarded to an electronic computing device connected to the temperature sensor. The electronic computing device is configured to monitor the first sensor signal for exceeding a defined threshold value. The invention also relates to a vehicle and a method for regulating the temperature of a multilayer composite structure.

[0002] In automotive engineering, soft interior surfaces are achieved using multi-layer structures. These structures often comprise a foam layer and a top layer. This allows components such as door panels, instrument panels, or armrests to be created. Heating wires are often used to heat such surfaces. To prevent visual and tactile markings from the wires on the surface, these wires are usually located beneath a foam layer. Due to the fact that there is usually a distance of more than 10 mm between such heating wires and the top layer of the multi-layer composite material, the desired heating is only achieved with a time delay.

[0003] Another disadvantage is that the wires are usually laid with a relatively large spacing, which can create warm and cold regions on the surface of the multilayer composite material, which is extremely undesirable.

[0004] Therefore, the aim is to arrange layers that are as thin and large-area heatable as possible within the multilayer composite material close to the surface.

[0005] From EP 1 924 125 B1 it is known to make a polymer layer based on polyurethane or PVC electrically conductive by adding conductive additives, for example nanotubes, silver, ionic liquids, graphite particles and / or copper particles to the pasty plastic material before the layer is formed, in order to heat it electrically directly after the layer has been formed by means of current flow.

[0006] DE 10 2020 215 949 A1 discloses a method for producing an electrically heatable layer from a paste-like plastic material, wherein a contacting additive is further dispersed into the plastic material, thereby making electrical contact with the electrically heatable layer easier and more reliable. The paste-like plastic material can be applied to the carrier material using a printing process, allowing, for example, structures in the form of conductor tracks for supplying power to the electrically heatable layer to be formed.

[0007] Unfortunately, the surfaces can heat up to such high temperatures that direct contact with human skin is at least perceived as unpleasant or can even cause harmful burns.

[0008] Due to the increasing digitalization of vehicles and the associated collection of sensor data, sensors are increasingly being installed in the surfaces of vehicle interiors in modern vehicle applications. For high-resolution measurements, the sensors must be integrated close to the surface.

[0009] DE 10 2021 211 134 A1 discloses a cushioning element with an electrically conductive functional layer arranged beneath a cover. The functional layer can, for example, form a proximity sensor. However, the combination of such a proximity sensor in a functional relationship with other functional layers is not known.

[0010] The invention is based on the object of providing a heatable multilayer composite structure that can detect an impending touch of the surface by a user. Additionally or alternatively, a solution is to be provided that, upon detection of an impending touch, can adjust the temperature of the surface of the multilayer composite structure in such a way that contact with a surface that is perceived as unpleasantly warm or even causes burns can be avoided.

[0011] The solution to this problem is provided by a system having the features of independent claim 1.

[0012] Further advantageous embodiments are disclosed in the dependent claims. A further solution to the problem is provided by a vehicle with a system according to the invention as defined in claim 7.

[0013] Claim 8 relates to a method for controlling the temperature of a multilayer composite structure.

[0014] Further advantages and features can be found in the general description and the exemplary embodiments.

[0015] The present invention relates to a system comprising a multilayer composite structure with a single-layer or multilayer top layer, a heating layer formed from a first electrically conductive layer, and at least one temperature sensor. A first sensor signal from the temperature sensor can be forwarded to an electronic computing device connected to the temperature sensor, wherein the electronic computing device is configured to monitor the first sensor signal for exceeding a defined threshold value. The composite structure has at least one proximity sensor, wherein a second sensor signal from the proximity sensor can be forwarded to the electronic computing device.The electronic computing device is designed to evaluate the second sensor signal and to detect an impending contact of the composite structure, wherein the electronic computing device is designed to output a control signal and to reduce or interrupt the heating power of the heating layer after detecting an impending contact and exceeding the threshold value.

[0016] The top layer forms the visible front side of the composite structure. In other words, the top layer is visible from the outside, so the top layer determines the visual appearance of the composite structure. The top layer is preferably made of a polymeric material, for example a thermoplastic polyolefin or a polyurethane. However, the top layer can also comprise or be formed from a textile fabric or genuine leather. The top layer can have a visible front side with a possibly relief-like surface structure in the form of a grain, as is typically the case with a surface film or artificial leather. This can impart pleasant visual and tactile properties to the surface of the composite structure, the effect of which can be enhanced by structuring, e.g. in the form of embossing on the outer side of the top layer forming the surface of the composite structure.

[0017] The computing device can be arranged inside or outside the composite structure and connected to the composite structure via lines for data and / or signal exchange. The composite structure according to the invention and the computing device together form a proximity detection system.

[0018] The use of a separate temperature sensor can be dispensed with if the heating layer has a temperature-dependent resistance, preferably in the form of a PTC resistor. A characteristic curve stored on the electronic computing device can be used to assign a temperature to each resistance value of the electrically conductive layer, so that the heating layer itself can form the temperature sensor. The heating layer or the electrically conductive layer can be printed either directly onto the back of the top layer or onto another film-like substrate and then laminated onto the back of the top layer. To print the electrically conductive layer, a pasty material can be mixed with electrically conductive additives, for example made of carbon or silver. It has been proven advantageous that the electrically conductive layer can be made particularly thin and flexible in this way.The electrically conductive layer can thus be arranged directly beneath the top layer without the visual and tactile impression of the visible front side of the top layer being negatively affected by rigid and locally arranged electronic components. By arranging the electrically heatable layer close to the surface, e.g. directly on the back of the top layer, faster and / or more energy-efficient and / or more uniform heating of the top layer can be enabled. The flat design of the heating layer also has a positive effect here compared to a wire. If, for example, the heatable multi-layer composite structure is used as a radiant heater in the interior of a vehicle, temperatures of over 60°C, preferably no more than 80°C, can be reached on the surface of the composite structure.

[0019] The threshold value represents a maximum permissible temperature up to which contact with the surface by a user is safe. Depending on the design of the system, the threshold value can, for example, be a temperature of 60 °C, at which, according to DIN EN ISO 13732-1 -2008-12, the contact time until a burn occurs for plastic materials is one minute. In other words, the composite structure in this example can cool down to a value below 60 °C within one minute without posing a health risk to the user upon contact. By keeping the heat capacity and / or thermal conductivity of the materials of the composite structure as low as possible, the fastest possible cooling after the heating output of the heating layer is reduced or interrupted.

[0020] The proximity sensor and / or the temperature sensor can also be produced in a comparable manner using printed electrically conductive structures. The temperature sensor and / or the proximity sensor can each be formed as a separate electrically conductive layer. Alternatively, the temperature sensor and / or the proximity sensor and / or the heating layer can be arranged within an electrically conductive layer or formed by it. By simultaneously combining the electrically conductive layer as a sensor and heating element, the number of components that would exclusively fulfill the function of a sensor or a heating element can be reduced. By integrating several functions into the electrically conductive layer, a particularly compact and / or cost-effective construction of the multilayer composite structure can be achieved.

[0021] By printing the electrically conductive structures, the conductor tracks of the heating layer and / or the temperature sensor and / or the proximity sensor can already be provided within the multilayer composite structure. This can reduce or completely eliminate the effort required for external wiring of the electrically conductive layer. The conductor tracks are freely accessible in some places, allowing the contact points to be electrically connected to external devices, e.g., with plug or crimp connections. The contact position can be freely selected by appropriately laying out the printed conductor tracks. It is particularly advantageous to route the upper layer around the component edge to the back of a lower layer and to be able to attach the plug or crimp connectors there in an invisible area.In addition to the first electrically conductive layer, further electrically conductive layers can be arranged below the upper layer.

[0022] Alternatively, the proximity sensor and / or the temperature sensor can be implemented as commercially available electrical components, so-called SMD components, arranged on a circuit board or printed circuit board. The proximity sensor can be arranged either on an outer side of the top layer, preferably in an edge region of the composite structure that is outside the area visible to the user, or within the composite structure.

[0023] The heating layer or the electrically conductive layer and / or the proximity sensor and / or the temperature sensor can be connected to a voltage source for power supply. The temperature sensor and the proximity sensor are connected to the electronic computing device or the evaluation electronics to transmit the sensor signals.

[0024] In a particularly advantageous manner, the system according to the invention can reduce or even stop the heating power of the heating layer as soon as a user approaches, in order to be able to cool the surface of the multi-layer composite structure down to the point of contact, if necessary, so that the user is not exposed to unpleasantly high temperatures upon contact or at least does not suffer burns.

[0025] According to a further aspect of the present invention, the proximity sensor is designed as a capacitive sensor comprising the first electrically conductive layer, a dielectric and a second electrically conductive layer.

[0026] The second electrically conductive layer can also be formed as a heating layer. In other words, the first electrically conductive layer can form both a heating layer and a first electrode of the capacitive sensor. The second electrically conductive layer can also form both a heating layer and a second electrode of the capacitive sensor. The dielectric can be formed by a polymeric, electrically non-conductive layer.

[0027] Viewed in one plane, several independent capacitive sensors can be arranged, which together form a sensor arrangement.

[0028] According to a further aspect of the present invention, the proximity sensor is designed as an optical sensor, an infrared sensor or an ultrasonic sensor.

[0029] The optical sensor can preferably be a so-called "time-of-flight" sensor, which requires particularly little installation space due to its simple design without any moving parts. At the same time, data evaluation can be carried out particularly quickly and precisely. The proximity sensor can be arranged either on an outer side of the top layer, preferably in an edge region of the composite structure that lies outside the area visible to the user, or within the composite structure, preferably directly below the top layer, which is at least partially translucent or entirely translucent or transparent. For the use of an ultrasonic sensor, it can be particularly advantageous if the top layer is perforated or perforated. This allows the top layer to be permeable to ultrasonic waves. This allows the ultrasonic sensor to be placed beneath the top layer, invisible from the outside, without negatively affecting its functionality.

[0030] A further advantageous embodiment of the present invention provides that the multilayer composite structure has a base layer made of a polymer foam. The polymer foam can be made of polyvinyl chloride, polyolefin, or polyurethane. The polymer foam can optionally have an adhesion-promoting layer to create an adhesive bond with one of the electrically conductive layers. The polymer foam of the base layer can, for example, be laminated onto the at least first electrically conductive layer and impart a particularly soft and high-quality visual and / or tactile impression to the composite structure.

[0031] According to a further aspect of the present invention, the upper layer is translucent. In a particularly advantageous manner, an optical proximity sensor or an infrared sensor can also be arranged below the upper layer if the upper layer is translucent, i.e. at least partially transparent to light. In a particularly advantageous manner, the light transmittance of the upper layer is 1% to 50% in a wavelength range for visible light between 400 nm and 780 nm or in a wavelength range for infrared light between 780 nm and 10,000 nm, particularly preferably in a wavelength range for short-wave infrared light in a wavelength range between 780 nm and 1400 nm. The translucent upper layer is thus sufficiently transparent to enable the approach of a user to be adequately detected via the optical proximity sensor below the upper layer. At the same time, elements of the proximity sensor can be arranged in the composite structure so that they are invisible from the outside due to the diffuse light distribution of the translucent upper layer.

[0032] Alternatively, the top layer can also be transparent, meaning it is completely permeable to visible light in a wavelength range between 400 nm and 780 nm. This allows the optical proximity sensor to detect a user's approach with particularly high accuracy and sensitivity.

[0033] According to a further aspect of the present invention, the multi-layer composite structure is part of a trim element. Thus, the multi-layer composite structure can be part of any trim element with a decorative surface, which offers functional added value through the additional sensor function and electrical heating capability, without negatively impacting the visual and tactile appearance. Preferably, the trim element can be a dashboard, an armrest, or a door panel in the vehicle interior. In this way, various surfaces in the vehicle interior can be heated and dissipate heat over a large area without the trim element posing a risk of burns to vehicle occupants upon contact with the surfaces.

[0034] According to a further aspect of the present invention, the aforementioned properties and advantages can be transferred to a vehicle with a system according to the invention.

[0035] The present invention further relates to a method for controlling the temperature of a multilayer composite structure using the system according to the invention, characterized by the following method steps: a) detecting a first sensor signal by the at least one temperature sensor and forwarding the first sensor signal to the electronic computing device, b) detecting a second sensor signal by the at least one proximity sensor and forwarding the second sensor signal to the electronic computing device, c) evaluation of the first sensor signal for exceeding a defined threshold value by the electronic computing device, d) Evaluation of the second sensor signal and, if necessary, detection of an impending contact with the surface of the composite structure by the electronic computing device, e) Output of a control signal after detection of an impending contact and exceeding of the threshold value to reduce or interrupt the heating power of the heating layer.

[0036] The above-mentioned properties and advantages of the system according to the invention are equally valid for the claimed method.

[0037] It is expressly pointed out that the above-explained embodiments of the invention can be combined individually or in any technically reasonable combination with each other with the subject matter of claim 1 and / or the independent claim 8.

[0038] With reference to the drawings, exemplary embodiments of the invention are schematically illustrated and explained in more detail below. Fig. 1 shows a schematic representation of the system according to the invention according to a first embodiment in a sectional view. Fig. 2 shows a schematic representation of the system according to the invention according to a second embodiment in a sectional view. Fig. 3 shows a schematic representation of the system according to the invention according to a third embodiment in a sectional view.

[0039] The Fig. 1 shows a system 10 with a multi-layer composite structure 1 with an upper layer 2, a first electrically conductive layer 3, a dielectric 6, a second electrically conductive layer 7 and a lower layer 8. The first electrically conductive layer 3, the dielectric 6 and the second electrically conductive layer 7 together form a proximity sensor 5 designed as a capacitive sensor. The first electrically conductive layer 3 also has a temperature sensor 9.

[0040] The first electrically conductive layer 3 and the second electrically conductive layer 7 can be heated by their internal resistance when current flows, so that the multilayer composite structure 1 can also be used as a surface heating element, e.g., for heating surfaces in automotive interiors. The first electrically conductive layer 3 is printed as a pasty mass onto the back of the upper layer 2 using a printing process. The dielectric 6 is applied to the first electrically conductive layer 3. The dielectric 6 is formed by a polymeric, electrically non-conductive layer. The lower layer 8 made of polymer foam is laminated onto the second electrically conductive layer 7 with the aid of an additional adhesion promoter layer. An electronic computing device 4 is arranged outside the composite structure 1.The temperature sensor 9 is connected to the computing device 4 via a line for data exchange, wherein a first sensor signal S1 of the temperature sensor 9 can be forwarded to the electronic computing device 4. The electronic computing device 4 monitors the first sensor signal S1 for whether a defined threshold value S1 is exceeded. max . The threshold value S1 max represents a maximum permissible temperature up to which contact with the surface by a user is safe. A second sensor signal S2 of the proximity sensor 5 can also be forwarded to the electronic computing device 4, wherein the electronic computing device 4 evaluates the second sensor signal S2 and can detect an impending contact with the composite structure 1. After detecting an impending contact and exceeding the threshold value S1 maxa control signal S3 is output by the computing unit 4 to reduce or interrupt the heating power of the heating layer 3.

[0041] The Fig. Figure 2 shows the system 10 according to the invention according to a second embodiment. In contrast to the illustration of Fig. 1 shows the composite structure 1 of the Fig. 2 has only a single electrically conductive layer, namely the first electrically conductive layer 3 designed as a heating layer with the temperature sensor 9. On an outer side of the upper layer 2, two optical proximity sensors 5 are arranged at the outer edge regions of the composite structure 1.

[0042] The Fig. 3 shows the system 10 according to the invention according to a third embodiment. In contrast to the illustration of Fig. 2 shows the composite structure 1 of the Fig.3 has two optical proximity sensors 5 arranged below the top layer 2 within the composite structure 1. The first electrically conductive layer 3 has a recess in the area where the proximity sensors 5 are arranged. The proximity sensors 5 and the first electrically conductive layer 3 are arranged in one plane. To ensure that the optical proximity sensors 5 can detect the approach of a user with sufficient precision and reliability, the top layer 2 is translucent. List of reference symbols (part of the description) 1 Multilayer composite structure 2 upper class 3 first electrically conductive layer, heating layer 4 electronic computing device 5 Proximity sensor 6 Dielectric 7 Second electrically conductive layer 8 Lower class 9 Temperature sensor 10 systems S1 first sensor signal of the temperature sensor S1 max Threshold of the first sensor signal S2 second sensor signal of the proximity sensor S3 control signal QUOTES CONTAINED IN THE DESCRIPTION

[0000] This list of documents submitted by the applicant was generated automatically and is included solely for the convenience of the reader. This list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions. Cited patent literature

[0000] EP 1 924 125 B1

[0005] DE 10 2020 215 949 A1

[0006] DE 10 2021 211 134 A1

[0009] Cited non-patent literature

[0000] DIN EN ISO 13732-1 -2008 - 12

[0019]

Claims

[1] System (10) comprising a multi-layer composite structure (1) with a single-layer or multi-layer top layer (2), a heating layer (3) formed from a first electrically conductive layer (3) and at least one temperature sensor (9), wherein a first sensor signal (S1) of the temperature sensor (9) can be forwarded to an electronic computing device (4) connected to the temperature sensor (9), wherein the electronic computing device (4) is designed to detect the first sensor signal (S1) when a defined threshold value (S1 max ) to monitor, characterized by , that the composite structure (1) has at least one proximity sensor (5), wherein a second sensor signal (S2) of the proximity sensor (5) can be forwarded to the electronic computing device (4), wherein the electronic computing device (4) is designed to evaluate the second sensor signal (S2) and to detect an impending contact of the composite structure (1), wherein the electronic computing device (4) after detecting an impending contact and exceeding the threshold value (S1 max ) is designed to output a control signal (S3) and to reduce or interrupt the heating power of the heating layer (3). [2] System (10) according to claim 1, characterized by that the proximity sensor (5) is designed as a capacitive sensor, comprising the first electrically conductive layer (3), a dielectric (6) and a second electrically conductive layer (7). [3] System (10) according to claim 1, characterized bythat the proximity sensor (5) is designed as an optical sensor, an infrared sensor or an ultrasonic sensor. [4] System (10) according to one of the preceding claims, characterized by that the multi-layer composite structure (1) has a base layer (8) made of a polymer foam. [5] System (10) according to one of the preceding claims, characterized by that the upper layer (2) is translucent. [6] System (10) according to one of the preceding claims, characterized by that the multi-layer composite structure (1) is part of a cladding element. [7] Vehicle with a system (10) according to one of the preceding claims. [8] Method for controlling the temperature of a multilayer composite structure (1) using a system (10) according to one of claims 1 to 6, characterized by the following procedural steps: a) detecting a first sensor signal (S1) by at least one temperature sensor (9) and forwarding the first sensor signal (S1) to an electronic computing device (4), b) detecting a second sensor signal (S2) by at least one proximity sensor (5) and forwarding the second sensor signal (S2) to the electronic computing device (4), c) Evaluation of the first sensor signal (S1) for exceeding a defined threshold value (S1 max ) by the electronic computing device (4), d) evaluation of the second sensor signal (S2) and, if necessary, detection of an impending contact with the surface of the composite structure (1) by the electronic computing device (4), e) Output of a control signal (S3) after detection of an impending contact and exceeding of the threshold value (S1 max ) to reduce or interrupt the heating power of the heating layer (3).

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