Sensor system and method for condition determination

Abstract

The invention relates to a sensor system for use in a vehicle by means of which temperature differences can be determined in various areas and conclusions can be drawn about the heat input into these areas. Furthermore, the invention relates to a method for determining the condition using a sensor system and the use of a sensor system in a vehicle chassis.

Description

[0001] The present invention relates to a sensor system and a method for determining the condition in a vehicle.

[0002] Sensor systems for monitoring the condition of individual components and assemblies of a vehicle are already known from the state of the art. Modern motor vehicles, such as passenger cars or commercial vehicles, use a large number of sensors, which are evaluated in central data processing units to provide a commercial vehicle driver or a mechanic in the workshop with information regarding the individual vehicle components. However, a disadvantage of the sensor systems known from the state of the art has proven to be the need to install a large number of cables, which not only increases the weight of the vehicle but also, due to their sheer number, makes the vehicle's wiring confusing.In addition, the large number of cables typically installed on a motor vehicle also makes it prone to errors, as the probability of a cable break understandably increases with the number of cables installed and, at the same time, troubleshooting becomes more difficult with a large number of cables.

[0003] The object of the present invention is to provide a sensor system that is particularly simple in design. Relatedly, the object of the present invention is also to offer a method for determining the condition that avoids the disadvantages known from the prior art.

[0004] This object is achieved with a sensor system according to claim 1 and a method according to claim 14. Furthermore, the use of a sensor system in a vehicle is proposed.

[0005] According to the invention, a sensor system is provided for use in a vehicle, comprising a first conductor and a vehicle part, wherein the first conductor is made of a different material than the first vehicle part, wherein the first conductor is electrically conductively connected to the vehicle part only in a first measuring section and is fixed to the vehicle part at a distance from the first measuring section and electrically insulated from the material of the vehicle part, wherein in the first measuring section there is a first temperature which is present both in the material of the first conductor in the region of the first measuring section and in the material of the vehicle part in the first measuring section, wherein the first conductor is arranged and fixed to the vehicle part at a distance from the first measuring section in such a way that the first conductor has a second temperature in the region of the second measuring section,which is essentially also present in the material of the vehicle part in the second measuring section, wherein the sensor system comprises a measuring unit which is designed to measure a first electrical voltage between the first conductor and the vehicle part in the region of the second measuring section and to calculate a first temperature difference from this first electrical voltage. The combination of the first conductor and the vehicle part thus functions as a thermocouple. Such thermocouples are known per se as measuring sensors from the prior art. Accordingly, a thermocouple is formed from two electrical conductors, in particular metals, which consist of different materials. A first end of the two electrical conductors is electrically conductively connected to one another and arranged in a first measuring section. The two separate,The distally opposite ends of the two electrical conductors are arranged in a second temperature range, and due to the difference in temperature between the first end and the second end of the respective conductor, a so-called thermoelectric voltage can be measured between the two loosely lying conductor ends in the second temperature range. This voltage depends on the temperature difference between the first temperature range and the second temperature range. Instead of using a conventional thermocouple in the vehicle area, the vehicle part itself is used as one of the conductors of the thermocouple, whereby only one additional conductor is required to achieve the same function as with a conventional thermocouple. It is of course important that the material combination of the manufacturing material of the vehicle part and the first conductor is suitable,to allow a reliable determination of the temperature difference between two measuring sections. Within the scope of the present invention, it is therefore provided that the manufacturing material of the first conductor is adapted to the manufacturing material of the vehicle part. In a very basic embodiment of the present invention, it is provided that the sensor system determines a temperature difference between a first measuring section and a second measuring section,wherein a first temperature is present in the first measuring section and a second temperature is present in the second measuring section. In the first measuring section, the first conductor and the vehicle part are electrically connected to one another and arranged electrically insulated from one another over the remaining extent of the first conductor up to the second measuring section. The electrical connection between the first conductor in the first measuring section and the vehicle part is preferably established by soldering with metallic solder. Alternatively, the first conductor can be inserted into a recess in the vehicle part and clamped there. By strategically arranging the first measuring section in the area of, for example, a vehicle chassis, a critical temperature in the first measuring section can be determined even with this simplest embodiment of the sensor system. This can be the case, for example,when an unusually high temperature prevails in the area of ​​the rolling bearings of a wheel suspension, which is very high compared to a second, more outwardly located area on an axle stub. In this case, the sensor system can detect a high temperature difference, which indicates a potential fault in one of the rolling bearings of the vehicle's wheel suspension. To determine a temperature difference, the sensor system has a measuring unit that calculates a first temperature difference corresponding to this voltage from a first electrical voltage determined in the second measuring section, i.e., the thermoelectric voltage between the material of the vehicle part and the material of the first conductor, between the distal end of the first conductor and the vehicle part. For this purpose, the measuring unit is equipped with a data processing system, in particular a computer.which is connected to a memory in which corresponding data on specific material pairings and the resulting thermoelectric voltages are stored, which in turn represent a specific temperature difference for this specific material pairing. Such data is typically determined in series of tests in which, for known temperature differences, the corresponding voltages at the loose ends of a thermocouple with a specific material pairing are determined. The advantage of using only one conductor in combination with the vehicle part, which is already made of metal and therefore electrically conductive, is that the sensor system is simple and cost-effective, and the electrical conductor can be accommodated in the chassis in a particularly space-saving manner.

[0006] In one embodiment of the sensor system, the first conductor is fixed to the vehicle part in a form-fitting and / or material-fitting manner in the area between the first and second measuring sections. Advantageously, the first conductor is therefore not only fixed to the vehicle part in the area of ​​the first measuring section, but also advantageously fixed to the vehicle part over the majority of its extension between the first and second measuring sections. This avoids cable clutter and, in particular, allows for a space-saving arrangement of the sensor system. Furthermore, the particularly close arrangement of the only electrical conductor to the vehicle part also reduces the susceptibility to errors, as the electrical conductor can be snuggled up to the vehicle part, so to speak. This avoids loose parts of the conductor that protrude from the vehicle part and thus also ensures its mechanical safety.In other words, the conductor according to the present invention is very well protected against environmental influences and mechanical effects.

[0007] In one embodiment of the sensor system, the first vehicle part is made of a ferrous alloy, and the first conductor is made of a copper alloy. It has been shown that, in particular, a material combination of a ferrous alloy, as is commonly used in the chassis components of motor vehicles, and a copper alloy as the material of the first conductor produces particularly reliable thermal voltages, which allow for reliable temperature difference determination in the measuring unit.

[0008] The sensor system advantageously has a second conductor which is electrically connected to the vehicle part in a third measuring section and is arranged and fixed to the vehicle part at a distance from the third measuring section in the second measuring section or in a fourth measuring section such that the second conductor has the second temperature in the region of the second measuring section or a third temperature in the region of the fourth measuring section, which third temperature is also present in the material of the vehicle part in the region of the second or fourth measuring section, wherein the measuring unit is designed to measure a second electrical voltage between the second conductor and the vehicle part in the region of the second measuring section or the fourth measuring section and to calculate a second temperature difference from this second electrical voltage. The second conductor is preferably equipped with the same material properties as the first conductor.The second conductor is therefore also only electrically connected to the vehicle part or to a further, second vehicle part in the third measuring section and is connected to the measuring unit in the prescribed second measuring section or in a further, fourth measuring section. In this way, the measuring unit determines a temperature difference between the third measuring section and either the second or the fourth measuring section. The measuring unit is advantageously suitable for comparing and outputting the first temperature difference and the second temperature difference. Alternatively, the measuring unit is advantageously connected to an electronic data processing system already provided in the vehicle, which in turn compares the two temperature differences and draws a conclusion about the condition of the vehicle part or the vehicle system in the first and third measuring sections.

[0009] In one embodiment of the sensor system, the first measuring section is arranged adjacent to a bearing section of the vehicle part, wherein at least one rolling bearing is fixed to the vehicle part in the bearing section. Thus, the first measuring section is particularly preferably provided, for example, on an axle stub, and advantageously more precisely in the area of ​​the axle stub where the bearing seats for rolling bearings of a vehicle's wheel bearing are arranged. This arrangement of the first measuring section thus makes it possible to monitor the heat input into the axle stub by the rolling bearings. If the temperature difference increases between the rolling bearing area and another, generally cooler area of ​​the chassis, this can be considered an indication of bearing wear that needs to be recorded.When a certain limit temperature difference, previously determined in tests, is reached, the measuring unit or the vehicle's electronic data processing system can issue a warning to the driver or a workshop that a bearing is worn and should be replaced.

[0010] In one embodiment of the sensor system, the third measuring section is arranged adjacent to an area where a brake carrier or a brake disc is attached to the vehicle part. The arrangement of the additional, third measuring section in the area of ​​a brake carrier or a brake disc gives the sensor system the ability to relate the temperature difference between the first measuring section to the typically relatively high heat input from the braking system into the vehicle part. Thus, if the braking system causes a particularly high heat input into the vehicle part, both the temperature difference between the first measuring section and the second measuring section, as well as the temperature difference between the third and second measuring sections, can increase. However, in this case, this does not yet indicate increased wear in the vicinity of the first measuring section.In contrast, if the heat input from the braking system into the vehicle part is low and yet there is a large temperature difference between the first measuring section and the second measuring section, this can be an indication of increased wear near the first measuring section.

[0011] In one embodiment, the sensor system has at least one and preferably a plurality of further conductors which are electrically connected to the vehicle part or a further component of a vehicle chassis in further measuring sections and are connected to the measuring unit such that further temperature differences between the measuring sections and the second or fourth measuring section can be determined. The strategic arrangement and distribution of a plurality of measuring sections and corresponding conductors according to the present invention thus makes it possible to specifically monitor individual, critical areas of the vehicle chassis and to process unusual temperature differences between two specific measuring sections as an indication of increased wear. This makes it possible to issue warnings with information about where problems exist on the vehicle in order to specifically initiate maintenance work on the vehicle's chassis.

[0012] In one embodiment of the sensor system, at least one of the conductors is guided, at least in part, in a groove formed on the vehicle part. To accommodate the conductor in a particularly protected manner in the area of ​​the vehicle part, a groove is preferably formed in the vehicle part, into which the conductor is inserted entirely or at least partially.

[0013] In one embodiment of the sensor system, at least one of the conductors is designed as a flat, preferably self-adhesive strip. In addition or alternatively to arranging the conductor in a groove, it is preferably designed as an electrically conductive, foil-like, and self-adhesive element. This allows, in particular, the subsequent manufacture of a sensor system according to the present invention on existing chassis and vehicle parts without requiring any mechanical modification of the available installation space or the existing vehicle parts.

[0014] In one embodiment of the sensor system, at least one of the conductors is printed onto the vehicle part. As an alternative to a self-adhesive and electrically conductive film, the conductor(s) can also be printed onto the vehicle part. It goes without saying that in this case, an insulating layer must be provided between the respective conductor and the vehicle part outside the respective first or third measuring section in order to achieve electrical insulation between the two layers. Printing the conductor(s) onto the vehicle part, similar to self-adhesive film, has the advantage of only requiring minimal space. A particularly advantageous feature here is that the conductor can be applied to the vehicle part even with a particularly complicated geometry that may circumvent obstacles, which would only be possible with increased effort using a film or cable.

[0015] According to the invention, the use of a sensor system as described above in a commercial vehicle is provided for determining undesirably high temperatures in a specific area of ​​a vehicle part to be monitored, wherein the first measuring section is arranged in the area to be monitored and wherein a third measuring section is arranged in a reference area of ​​the commercial vehicle. The sensor system described above is particularly suitable for use in a commercial vehicle, in particular in its chassis. The particularly space-saving design of the sensor system allows for particularly effective use of the available installation space in the commercial vehicle.Furthermore, the use of a previously described sensor system in a commercial vehicle enables particularly high operational reliability, as the sensor system itself is optimally protected against mechanical influences, and the data acquired by the sensor system allows for particularly precise monitoring of material wear in specific areas of the commercial vehicle chassis. The sensor system is advantageously used to compare the temperature differences between a monitored area and a reference area. This allows temperature increases in the monitored area to be related to the temperature increases in the rest of the commercial vehicle's chassis, thus enabling more precise fault detection.

[0016] When using the sensor system, the area to be monitored preferably includes at least one rolling or plain bearing, with the reference area preferably being the connection area of ​​a braking system. In particular, the comparison between the connection area of ​​a brake disc or brake carrier and the area of ​​the rolling and plain bearings allows for a particularly precise condition determination in the commercial vehicle chassis. This allows the high heat input typically occurring in the brake area to be calculated from the temperature monitoring in the bearing area, allowing a clearer conclusion about the heat input actually occurring in the bearing area.

[0017] When using the sensor system, a heat flow ratio between the area to be monitored and the reference area is preferably determined from two temperature differences (ΔT1, ΔT2) of the sensor system determined by the measuring unit. The heat flow ratio is in particular an expression of the heat input that occurs in the reference area in relation to the heat input that occurs in the area to be monitored. If a worn bearing in the monitored area of ​​the chassis is heavily worn and thus causes a high heat input, this can be compared to the usually very high heat input caused by the braking system of a chassis. The condition of the chassis system can therefore be determined using the proposed sensor system independently of the outside temperatures in which the vehicle, particularly preferably the commercial vehicle, is moving.

[0018] According to the invention, a method for condition monitoring in a vehicle is provided, comprising the steps: a) providing a vehicle part on which at least one first conductor is arranged and fixed, wherein the first conductor is electrically conductively connected to the vehicle part only in a first measuring section; b) connecting a measuring unit to the first conductor and to the vehicle part in a second measuring section; c) determining a first electrical voltage between the first conductor and the vehicle part in the second measuring section; d) Calculating a first temperature difference between the first and second measuring sections.

[0019] The proposed method is therefore particularly simple to implement, since, to prepare the sensor system used, only a conductor needs to be placed on a vehicle part and electrically connected to the vehicle part in a first measuring section. In a second measuring section, which is spaced apart from the first measuring section, a voltage is then simply measured, which reflects a specific temperature difference between the first and second measuring sections. Based on this temperature difference, a conclusion can be drawn about the condition of the vehicle part in the first measuring section.

[0020] Preferably, the method comprises the following further steps: e) providing a second conductor which is electrically connected to the vehicle part only in a third measuring section; f) connecting the measuring unit to the second conductor in the second measuring section or in a fourth measuring section; g) determining a second electrical voltage between the second conductor and the vehicle part in the second measuring section or fourth measuring section; h) calculating a second temperature difference between the third measuring section and the second or fourth measuring section; i) Comparing the first with the second temperature difference and determining a

[0021] Heat flow ratio between the first and third measuring sections. By expanding the sensor system used in the method with one or more additional conductors, a variety of other areas of the vehicle can be monitored during the monitoring process. Thus, a single measuring unit can determine a variety of different temperature differences, which, when compared to one another, provide precise status data on the wear of individual components at various locations in a vehicle. The monitoring process is therefore particularly precise and, by attaching only one conductor between each two measuring sections, requires only minimal resources and installation space.

[0022] Further advantages and features of the present invention will become apparent from the following description of selected embodiments with reference to the accompanying figures.

[0023] They show: Fig. 1 a partially sectioned view of a region of a landing gear, with a sensor system arranged thereon; Fig. 2 a schematic view of a sensor system; Fig. 3 and Fig. 4 two sectional views of a preferred embodiment of a sensor system; and Fig. 5 a schematic block diagram of the measuring section and the measuring unit.

[0024] Fig. 1 shows the wheel suspension area of ​​a typical commercial vehicle chassis with an embodiment of a sensor system 1 according to the present invention. The sensor system has a first conductor 4, which is fixed to a vehicle part 2 in a first measuring section A and is electrically connected to the vehicle part 2 there. In a second measuring section B, a measuring unit 5 measures a first voltage V1 between the first conductor 4 and the vehicle part 2. In addition, the sensor system 1 preferably has a second conductor 6, which is electrically connected to the vehicle part 2 in a third measuring section C and also ends in the second measuring section B. In the second measuring section, the measuring unit 5 measures a second voltage V2 between the second conductor 6 and the vehicle part 2.The first measuring section A is advantageously arranged in a bearing section 22, preferably characterized by at least one rolling bearing 24, while the third measuring area C is arranged near the connection area of ​​a braking system 9. In the preferred embodiment shown in FIG. Fig. In Figure 1, the vehicle part 2 is the axle stub of a commercial vehicle wheel suspension. However, it is understood that any other attachment or assembly of a vehicle can also be used as a vehicle part within the meaning of the present invention; this only needs to be made of metal in order to function as a thermocouple in a suitable material pairing with a suitable conductor.

[0025] Fig. 2 shows a schematic view of a further embodiment of the present invention. Here, the first measuring area A is again arranged near a first rolling bearing 24, wherein a monitoring area U is defined in this area in accordance with the present invention. Furthermore, a reference area R is defined near the fastening of a brake system 9, wherein the third measuring section C is arranged in this reference area. As in the embodiment of Fig. 1, a first conductor 4 is electrically conductively connected to the vehicle part 2 in the first measuring section A and a second conductor 6 is electrically conductively connected to the vehicle part 2 in the third measuring section C. The measuring unit 5 in this exemplary embodiment is designed to measure a first voltage between the first conductor 4 and the vehicle part in a second measuring section B and a second voltage in a fourth measuring section D between the second conductor 6 and the vehicle part 2. Furthermore, it is indicated that in addition to the first and second conductors 4, 6, a further conductor 8 can also be provided which is electrically conductively connected to the vehicle part 2 in a further measuring section E, which in this exemplary embodiment is arranged below the second rolling bearing 24, to the left of the first rolling bearing 24.It is understood that in addition to the 3 conductors shown, which are each connected to the vehicle part 2 in different areas, further additional conductors can also be provided, which are each electrically connected to the vehicle part 2 or to another vehicle part in a measuring section and can thus transmit a temperature difference ΔT from the respective measuring section to the measuring unit 5.

[0026] Fig. 3 shows a preferred embodiment in which the first conductor 4 and / or the second conductor 6 is arranged in a groove 26 formed on the vehicle part 2. In this embodiment, the corresponding conductor 4, 6 is arranged on the vehicle part 2 in a particularly space-saving manner and protected against environmental influences.

[0027] Fig. 4 shows an alternative to the Fig. 3, in which a conductor 4, 6 is designed as a flat strip and is arranged on the vehicle part 2 in a space-saving manner and with only a few protruding outer edges. It is understood in this context that a flat conductor 4, 6 designed as a strip can also be arranged in a groove 26 formed on the vehicle part 2, whereby a flat surface of the composite of conductor 4, 6 and vehicle part 2 is particularly preferably achieved.

[0028] Fig. Finally, Figure 5 shows a simplified block diagram, which particularly illustrates the measuring signals entering the measuring unit 5 and the respective voltage determined therefrom, as well as the temperature differences determined therefrom. A plurality of measuring sections A, B, C, D, E are arranged on the vehicle part 2, which is only shown schematically. A conductor 4, 6, 8 is provided in each case, which is laid between two measuring sections and is electrically connected to the vehicle part 2 in the left-hand measuring section A, C, E.Based on the principle that the voltage measured between a conductor 4, 6, 8 and the vehicle part 2 in the measuring section B, D, in which the vehicle part and the respective conductor are separated from each other, is in a specific relationship to the temperature difference ΔT existing between two measuring sections, the measuring unit 5 determines the corresponding temperature differences ΔT1, ΔT2, ΔTX from the respective voltages V1, V2, VX in a processor with a data memory (illustrated only schematically). From these temperature differences, in turn, a corresponding heat flow ratio Q can be determined, which is an expression for the ratio of the heat flows introduced into the vehicle part 2 in specific areas of the vehicle part 2.For example, if the heat flow ratio Q between an area of ​​the vehicle part 2 in which a rolling bearing is arranged on the vehicle part 2 and an area in which a brake carrier of a brake system 9 is arranged on the vehicle part 2 exceeds a certain value, i.e. the heat flow introduced in the bearing section 22 is unusually high, it can be concluded that there is disproportionately high wear in the corresponding bearing. It is understood that within the scope of the present invention the corresponding measuring sections A, C, E can be arranged at a plurality of selected locations on a vehicle part in order to be able to determine comparisons in these measuring sections between the existing temperature differences in relation to a spaced-off, preferably central measuring section B, D. In . Fig.5 also schematically indicates the possibility of providing one or more additional measuring sections on a further vehicle part 2', which are also connected to the measuring unit 5 in order to also be able to perform measurements of temperature differences occurring in other vehicle parts 2'. In addition to or as an alternative to determining unusual temperature conditions within a vehicle part 2, it is also possible to determine whether unusual temperature conditions exist between different vehicle parts 2, 2' of a vehicle. List of reference symbols: 1 sensor system 2 vehicle part 2' additional vehicle part 22 storage section 24 rolling bearings 26 grooves 4 first leader 5 measuring unit 6 second leader 9 Braking system A first measuring section B second measuring section C third measuring section D fourth measuring section E further measuring section Q heat flow ratio R Reference range U area to be monitored V1 first electrical voltage V2 second electrical voltage VX further electrical voltage ΔT1 first temperature difference ΔT2 second temperature difference ΔTX further temperature difference

Claims

[1] Sensor system (1) for use in a vehicle, comprising a first conductor (4) and a vehicle part (2), wherein the first conductor (4) is made of a different material than the first vehicle part (2), wherein the first conductor (4) is electrically conductively connected to the vehicle part (2) only in a first measuring section (A) and is fixed to the vehicle part (2) at a distance from the first measuring section (A) and is electrically insulated from the material of the vehicle part (2), wherein in the first measuring section (A) there is a first temperature which is present both in the material of the first conductor (4) in the region of the first measuring section (A) and in the material of the vehicle part (2) in the first measuring section (A), wherein the first conductor (4) is arranged and fixed in a second measuring section (B) on the vehicle part (2) at a distance from the first measuring section (A), such that the first conductor (4) has a second temperature in the region of the second measuring section (B), which second temperature is essentially also present in the material of the vehicle part (2) in the second measuring section (B), wherein the sensor system (1) comprises a measuring unit (5) which is designed to measure a first electrical voltage (V1) between the first conductor (4) and the vehicle part (2) in the region of the second measuring section (B) and to calculate a first temperature difference (ΔT1) from this first electrical voltage (V1). [2] Sensor system (1) according to claim 1, wherein the first conductor (4) is fixed in a form-fitting and / or material-fitting manner to the vehicle part (2) in the region between the first and the second measuring section (A, B). [3] Sensor system (1) according to one of the preceding claims, comprising a second conductor (6) which is electrically conductively connected to the vehicle part (2) in a third measuring section (C) and is arranged and fixed to the vehicle part (2) at a distance from the third measuring section (C) in the second measuring section (B) or in a fourth measuring section (D), such that the second conductor (6) has the second temperature in the region of the second measuring section (B) or a third temperature (T3) in the region of the fourth measuring section (D), which third temperature is also present in the material of the vehicle part (2) in the region of the second or fourth measuring section (B, D), wherein the measuring unit (5) is designed to measure a second electrical voltage (V2) between the second conductor (6) and the vehicle part (2) in the region of the second measuring section (B) or the fourth measuring section (D) and to calculate a second temperature difference (ΔT2) from this second electrical voltage (V2). [4] Sensor system (1) according to one of the preceding claims, wherein the first measuring section (A) is arranged adjacent to a bearing section (22) of the vehicle part (2), wherein in the bearing section (22) at least one rolling bearing (24) is fixed to the vehicle part (2). [5] Sensor system (1) according to claim 4, wherein the third measuring section (C) is arranged adjacent to a region of the fixing of a braking system (9) on the vehicle part (2). [6] Sensor system (1) according to claim 3, comprising at least one and preferably a plurality of further conductors (8) which are electrically conductively connected in further measuring sections (E) to the vehicle part (2) or a further component of a vehicle chassis and are connected to the measuring unit (5) in such a way that further temperature differences (ΔTX) between the measuring sections (E) and the second or fourth measuring section (B, D) can be determined. [7] Sensor system (1) according to one of the preceding claims, wherein at least one of the conductors (2, 4) is guided at least partially in a groove (26) formed on the vehicle part (2) and / or wherein at least one of the conductors (2, 4) is designed as a flat, preferably self-adhesive tape and / or wherein at least one of the conductors (2, 4) is printed on the vehicle part (2). [8] Use of a sensor system (1) according to claim 1 and claim 3 in a commercial vehicle for determining undesirably high temperatures in a specific area (U) of a vehicle part (2) to be monitored, wherein the first measuring section (A) is arranged in the area to be monitored (U) and wherein a third measuring section (C) is arranged in a reference area (R) of the commercial vehicle. [9] Use of a sensor system according to claim 8, wherein a heat flow ratio (Q) between the area to be monitored (U) and the reference area (R) is determined from two temperature differences (ΔT1, ΔT2) of the sensor system (1) determined by the measuring unit (5). [10] A method for monitoring the condition of a vehicle, comprising the steps of: a) providing a vehicle part (2) on which at least one first conductor (4) is arranged and fixed, wherein the first conductor (4) is electrically conductively connected to the vehicle part (2) only in a first measuring section (A); b) connecting a measuring unit (5) to the first conductor (4) and to the vehicle part (2) in a second measuring section (B); c) determining a first electrical voltage (V1) between the first conductor (4) and the vehicle part (2) in the second measuring section (B); d) Calculating a first temperature difference (ΔT1) between the first and the second measuring section (A, B).

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