Sensor unit and method of operating such a unit, and motor vehicle

Abstract

Sensor unit and method of operating such a unit, and motor vehicle. This sensor unit comprises a first analog signal transmitter for supplying measurement signals generated by a rotating element, and a second analog signal transmitter in the form of a temperature transmitter. A data processing device and an interface (8) are provided.The data processing device (6) is designed, in a basic state, to query, via the interface, only the measurement signals provided by the first analog signal transmitter (5) and to query, via the interface, the temperature-related measurement signals provided by the second analog signal transmitter at a specified time, which is determined based on a signal curve of the measurement signals that the data processing device (6) received from the first analog signal transmitter (5) during the query. Figure 1 for the abbreviation.

Description

Title of the invention: Sensor unit and method of operating such a unit, and motor vehicle

[0001] The invention relates to a sensor unit that can be used in particular in a motor vehicle. It also relates to a corresponding motor vehicle and a method of operating a sensor unit.

[0002] Sensors for detecting path or movement and / or speed are now widely used in various automotive applications, particularly in the field of tachographs. These sensors are designed specifically for more complex applications as small embedded microcontroller systems consisting of a sensor element and a microcontroller. These systems focus on the primary function, namely the accurate acquisition of path or movement and speed data. The components are optimized for efficient signal processing, reduced costs, and low power consumption.

[0003] For example, DE 10 2023 210 763.5, published after the filing of the present application, describes a sensor system operating on the principle of pulse detection. A sensor detects changes in the magnetic field of an associated pulse wheel. The sensor may include a pulse transmitter and is electromagnetically coupled to the pulse wheel. The pulse wheel or flywheel is connected to, or mounted on, a moving or rotating part of the vehicle. The pulse wheel may, for example, be connected to a drive shaft in the gearbox. Such a pulse wheel is generally disc-shaped with teeth on its outer edge. As the vehicle moves, the ferromagnetic pulse wheel rotates in front of the sensor, causing the teeth to slide against the sensor.A Hall effect IC (IC: Integrated Circuit), for example, that is, a Hall effect probe with a polarizing magnet, is mounted in the sensor. The sensor operates without contact, using the fact that the detected magnetic field varies with the movement of the pulse wheel. The magnetic field is notably stronger in front of a tooth than in front of an interdental space. The magnetic field is detected by the sensor as the teeth slide past the sensor and is converted in real time into pulses. The resulting sensor signal is, for example, in the form of an analog electronic signal, such as a voltage and / or current signal.

[0004] Such sensors are often used in extreme environmental conditions. These include very low to very high temperature ranges. The devices are also subjected to mechanical stresses such as vibrations and shocks. The sensors must therefore be robust and operate reliably.

[0005] The invention aims to contribute to the sustainable improvement of the performance and reliability of such systems.

[0006] The problem is solved by a sensor unit comprising:

[0007] .a first analog signal transmitter for the supply of measurement signals which are generated by a rotating element;

[0008] . a second analog signal transmitter for supplying signals from measurement at a temperature, in particular at a temperature relative to the rotating element;

[0009] . a data processing device, in particular a microcontroller; and

[0010] . an interface through which the data processing device is coupled to both to the first analog signal transmitter and to the second analog signal transmitter,

[0011] in which the data processing device is designed, in a basic state, to query, via the interface, only the measurement signals provided by the first analog signal transmitter and to query, via the interface, the temperature-related measurement signals provided by the second analog signal transmitter at a specified time which is determined according to a signal curve of the measurement signals that the data processing device received from the first analog signal transmitter during the query.

[0012] The problem is also solved by a motor vehicle with a shaft, in particular a drive shaft, on which is mounted a rotating element, in particular a pulse wheel, and with the sensor unit as defined above, in which the first analog signal transmitter detects measurement signals for the rotation of this rotating element on the shaft.The problem is also solved by a method of operating a sensor unit in which, on the one hand, a first analog signal transmitter for supplying measurement signals to a rotating element and, on the other hand, a temperature transmitter as a second analog signal transmitter share a common interface with a data processing device. In this method, the data processing device first queries measurement signals relating to this rotating element from the first analog signal transmitter and, depending on the signal profile of these measurement signals, provides a pause during which the data processing device queries measurement signals from the temperature sensor. Advantageous embodiments are shown below.

[0013] The sensor unit according to the invention comprises as follows:

[0014] - a first analog signal transmitter for supplying signals from measurements generated by a rotating element (in particular the aforementioned impulse wheel or flywheel);

[0015] - a second analog signal transmitter for supplying signals from measurement at a temperature, in particular at a temperature relative to the rotating element;

[0016] - a data processing device; and

[0017] - an interface through which the data processing device is coupled to both to the first analog signal transmitter and to the second analog signal transmitter,

[0018] in which the data processing device is designed, in a basic state, to query, via the interface, only the measurement signals provided by the first analog signal transmitter and to query, via the interface, the temperature measurement signals provided by the second analog signal transmitter at a specified time which is determined according to a signal curve of the measurement signals that the data processing device received from the first analog signal transmitter during the query.

[0019] The invention first introduces the idea of ​​measuring a temperature, doing so using the same sensor unit, and sending the signals to the same data processing device. It further incorporates the idea of ​​using a common interface. By querying the temperature at a defined time, determined by the evolution of the measurement signals to the rotating element, it is possible to pause the querying process to some extent, at a time that is as ideal as possible while remaining as harmless as possible to the success of the measurement. Thus, thanks to the common interface and the integration of the temperature sensor (a second analog signal transmitter), the sensor unit can be built compactly and made available at a cost-effective price.

[0020] According to a preferred embodiment, the data processing device is designed to perform the interrogation in the basic state several times over half a period of the period defined by the rotating element, in particular by a sequence of teeth on the rotating element, and preferably also several times over a quarter of the period defined by the rotating element. Thanks to a corresponding high-speed timing, the temperature measurement can be "intercalated" particularly easily. In the case of the unit mentioned above, frequencies of approximately 40 kHz, for example, can be useful for the reading.

[0021] According to another preferred embodiment of the invention, preferably in conjunction with the aforementioned preferred embodiment of obtaining the values data (repetition of the interrogation) at a high frequency, the data processing device is designed to make the interrogation of the measurement signals of the second analog signal transmitter so short that a complete digital signal can nevertheless be obtained, in particular calculated, for the signals of the first analog signal transmitter.

[0022] According to another preferred embodiment of the invention, it is further provided that, as in the case of the sensor system mentioned in the introduction, the first transmitter of analog signals comprises a magnetic sensor, preferably a magnetic sensor using the Hall effect.

[0023] According to another preferred embodiment of the invention, the sensor unit comprises a single analog-to-digital converter in or as an interface, which can be controlled or is controllable by the data processing device and which is connected or mounted and designed so that, according to the control, it sends the measurement signals from either the first or second analog signal transmitter to the data processing device. The control may be linked to a contactor associated with the analog-to-digital converter.

[0024] In this aspect, it is therefore possible to save another analog-to-digital converter by using the single analog-to-digital converter both for the rotation signals of the rotating element and for the temperature sensor (second transmitter of analog signals).

[0025] According to another preferred embodiment of the invention, the data processing device is designed to perform an analysis of the measurement signals from the first analog signal transmitter which have been received from it on the basis of at least the last two interrogations, preferably also on the basis of at least three, preferably again on the basis of at least four, preferably again on the basis of at least five, preferably again on the basis of at least six, preferably again on the basis of at least seven, preferably again on the basis of at least eight, preferably again on the basis of at least nine, preferably again on the basis of at least ten, preferably again on the basis of the last fifteen interrogations.

[0026] It is thus possible to predict the shape of the analog signal so that, as already stated, a digital signal can be reconstructed (calculated) despite the intermediate temperature requirement.

[0027] According to another preferred embodiment, the data processing device is designed to, after detection of the beginning of a flank in the trajectory of the measurement signals coming from the first analog signal transmitter, perform a temperature interrogation with the second analog signal transmitter under predetermined conditions. If the timing is sufficient (for example: several times in a quarter period as already mentioned), it is possible to predict the remaining shape of the flank and to forgo a limited number of subsequent measurement values.

[0028] The timing of the interrogation of the measurement signals by the first analog signal transmitter can be regular and the interrogation of the temperature can be carried out in the same timing, for example on one to two interrogation timings, preferably no more than five.

[0029] Temperature interrogation occurs under predetermined conditions: thus, it is naturally not necessary for the temperature to be interrogated at each rotation period of the rotating element. On a moving vehicle, the temperature will hardly change, even if the rotating element rotates 1,000 times, 10,000 times, or 100,000 times. Thus, temperature measurement can be carried out in units of 10,000 rotation periods, 100,000 rotation periods, 1,000,000 rotation periods, or 10,000,000 rotation periods, or the predetermined conditions for performing a temperature interrogation can be carried out in all the aforementioned embodiments of the sensor unit according to the invention as defined above at predetermined time intervals, for example, approximately every fifteen minutes. Depending on the state of the rotating element (of the vehicle), such time intervals could also be increased.

[0030] The motor vehicle according to the invention comprises a shaft, in which the drive shaft is here typically the central point, to which is fixed a rotating element, in particular a pulse wheel, and it comprises the sensor unit of the type according to the invention, also in all preferred embodiments, in which the first analog signal transmitter detects measurement signals for the rotation of this rotating element on the shaft.

[0031] The compact and economical sensor unit of the type of the invention is thus used practically in the motor vehicle according to the invention.

[0032] According to a preferred embodiment, the sensor unit in the motor vehicle is designed to also regularly detect the temperature, even when the shaft is not rotating (i.e., when the motor vehicle is stationary). Even in this case, temperature information can be useful; perhaps even for purposes completely different from those related to detecting the shaft's rotational speed, for example.

[0033] According to a preferred embodiment of the motor vehicle, the latter includes a memory in the sensor unit, in which temperature measurement values ​​are recorded. In particular, the data processing device is designed to store the temperature measurement values ​​in the memory. including, where applicable, the resulting data values ​​and, where applicable, other measured values, for example, those of the first analog signal transmitter. In this way, a long-term, or even multi-year, profile of the temperature curve can be obtained and subsequently read from the memory where applicable, so that long-term monitoring of the vehicle components, in particular the sensor unit itself, can be carried out and these components can then be optimized.

[0034] In the method according to the invention for the operation of a sensor unit in which, on the one hand, an analog signal transmitter for supplying measurement signals to a rotating element and, on the other hand, a temperature transmitter as a second analog signal transmitter share a common interface with a data processing device, the data processing device first queries measurement signals relating to this rotating element from the first analog signal transmitter and, depending on the signal profile of these measurement signals, provides a pause during which the data processing device queries measurement signals from the temperature sensor and then preferably returns to querying measurement signals relating to the rotating element from the first analog signal transmitter.

[0035] According to a preferred embodiment of the method, the temperature sensor measurement signals are further polled repeatedly, preferably even when the rotating element is stationary (i.e., in the example case, when the motor vehicle is stationary), and the corresponding data are stored in memory. In this case, the temperature measurement values ​​are preferably stored directly, but if necessary, they are stored in combination with the speed of the rotating element in order, among other things, to optimize an analysis.

[0036] To implement the described steps, a processor circuit may be provided, which includes programming or software comprising program instructions that, when executed, cause the processor circuit to implement an embodiment of the process. The processor circuit may, for this purpose, include at least one microprocessor and / or a microcontroller. The program instructions may be stored in a data memory of the processor circuit.

[0037] The invention also relates to specific embodiments of the method according to the invention, which have the characteristics already described in connection with specific embodiments of the sensor unit according to the invention and of the motor vehicle according to the invention. For this reason, the corresponding specific embodiments of the method according to the invention have not yet been described here.

[0038] For application cases or application situations that may arise with the method and that are not explicitly described here, it may be provided that, in accordance with the method, an error message and / or a request for input of user feedback is issued and / or that a default setting and / or a predefined initial state is set.

[0039] The invention also includes combinations of features of the embodiments described.

[0040] An example of an embodiment of the invention is described below. For this purpose:

[0041] [Fig.1] shows a motor vehicle according to an embodiment of the invention with a sensor unit according to an embodiment of the invention in a partial perspective view;

[0042] [Fig.2] shows the signals obtained from the first analog signal transmitter at the top and the digital signals derived from it at the bottom;

[0043] [Fig. 3] shows a curve of the analog signals from the first analog signal transmitter with an interrupt for temperature measurement at the top and the corresponding digital signal from the first analog signal transmitter at the bottom; and

[0044] [Fig.4] shows a temperature profile in the form of a bar graph which assigns a number of hours to the temperature ranges.

[0045] The embodiment described below is a preferred embodiment of the invention. In the embodiment, the described components of the embodiment represent individual features of the invention, which are to be considered independently of one another and which also improve the invention independently of one another and are therefore also to be considered as a constituent element of the invention individually or in a combination other than that shown. Furthermore, the described embodiment can also be supplemented by other features of the invention already described.

[0046] In the figures, functionally identical elements are each provided with the same reference characters.

[0047] Figure 1 schematically represents a vehicle 1. In this example, vehicle 1 is designed as a passenger car. In Figure 1, vehicle 1 is shown in a side-view perspective. The vehicle includes a drive shaft 2 which transmits power between a gearbox and the respective drive wheel of vehicle 1. To obtain motion information about vehicle 1, vehicle 1 also includes a sensor unit 4. The motion information may, for example, relate to or contain speed information v and / or displacement information w or path information. The motion information provides thus information which presents the speed of movement of vehicle 1 and / or the route / path already traveled by vehicle 1.

[0048] The sensor unit 4 comprises a first analog signal transmitter 5 and a processing unit 6 as a data processing device. The processing unit 6 includes, for example, one or more microprocessors or microcontrollers and is configured to perform or implement computational operations. These include, for example, processing a sensor signal SI to determine the desired motion information, which is provided by the first analog signal transmitter 5. To determine the motion information, the first analog signal transmitter 5 is electromagnetically coupled to a pulse wheel 3. In the present embodiment, the pulse wheel is fixed or mounted on the drive shaft 2. The mounting is such that the pulse wheel 3 moves with the drive shaft 2.The first analog signal generator 5 can detect the movement of the pulse wheel 3, and thus indirectly also the movement of the vehicle 1 via the drive shaft 2 in the form of pulses. The first analog signal transmitter 5 delivers the pulses in the form of a sensor signal.

[0049] The sensor unit 4 provides a pulse transmitter for generating a representative path and / or speed signal (sensor signal), which operates on the basis of dynamic adaptive pulse recognition. The first analog signal transmitter 5 can be installed or mounted in various locations in the vehicle, such as in a vehicle gearbox, on the drive shaft, or on the axles. The sensor signal is representative because the acquired displacement or path and / or speed information, as in the present embodiment on the drive shaft, is directly proportional to the vehicle's path or speed information.

[0050] The functionality of the sensor unit 4 is briefly summarized again below: For acquiring travel and / or speed information, the pulse wheel is fixed to the drive shaft 2 in the gearbox, for example. As illustrated in the embodiment shown in [Fig. 1], the pulse wheel is disc-shaped with teeth on its outer edge. While the vehicle 1 is moving, the ferromagnetic pulse wheel 3 rotates in front of the first analog signal transmitter 5. A Hall effect IC with a polarizing magnet, for example, is mounted in the first analog signal transmitter. The first analog signal transmitter therefore operates without contact. The first analog signal transmitter reacts, in particular, to variations in the magnetic field that occur when the pulse wheel 3, especially its teeth, The teeth pass in front of the first analog signal transmitter. This utilizes the fact that the magnetic field is stronger in front of a tooth than in front of an interdental space. The magnetic field is detected by the first analog signal transmitter as the teeth slide past it and, through dynamic adaptive pulse recognition, is converted in real time into pulses and delivered as a real-time signal. This real-time signal is the sensor signal SI, which can be, for example, an electrical signal, such as a voltage signal. The evolution of the sensor signal SI—that is, the pulses generated in response to the movement of the pulse wheel—represents the movement of the vehicle.For example, the number of teeth that have passed in front of the first analog signal transmitter allows us to determine the path traveled by the vehicle. The pulses per time contained in the sensor signal indicate, for example, a measurement of the vehicle's speed. Evaluating the sensor signal, for example in the processing unit, thus allows us to determine the desired motion information.

[0051] In the present case, in addition to the first analog signal transmitter 5, there is also a second analog signal transmitter 7, which is designed as a temperature transmitter, i.e., which provides measurement signals for a temperature, in particular a temperature related to the rotating element. The aim is to determine the prevailing temperature in the area of ​​the pulse wheel 3.

[0052] The second analog signal transmitter 7 also sends a signal S2 to the processing unit 6, which is to represent a data processing device within the meaning of the invention. An analog-to-digital converter 8 serves as an interface between the analog signal transmitters 5 and 7 on the one hand and the data processing device (processing unit) 6 on the other. The data processing device 6 is further equipped with a memory 9 in which the acquired measurement values ​​can be partially stored. This occurs primarily for the temperature measurement signals from the second analog signal transmitter 7.

[0053] The temperature no longer needs to be measured continuously; however, due to the common use of a single interface (the analog-to-digital converter 8), it is necessary to interrupt the polling of the SI signals from the first analog signal transmitter 5 in order to obtain the S2 signals from the second analog signal transmitter 7.

[0054] In this context, [Fig. 2] first illustrates a typical SI signal, as emitted by the first analog signal transmitter. Since the analog-to-digital converter 8 converts this sequence of SI signals, the data processing device 6 ultimately receives the digital signal D1, which may, however, have been processed here as part of data processing by the data processing device to obtain its final DI form represented here.

[0055] At some point, the temperature measurement must also be carried out, for example, every hour. It is possible that the motor vehicle 1 may now be momentarily stopped, but if this is not the case, it is sufficient to supply power to the data processing device 6 with the analog-to-digital converter 8 and, by nature, also the second analog signal transmitter 7 to enable operation. A measurement can then be easily carried out. If the motor vehicle 1 is not stopped, the temperature measurement must be carried out in some way in a signal sequence as shown in [Fig. 2] above in SI form. The exact way of doing this is explained in [Fig. 2].3] :

[0056] The data processing device (computing unit) 6 receives from the first. The analog signal transmitter sends a series of measurement signals M1, M2, M3, M4. Based on the signal curve, the device now recognizes this series as a rising edge. In the digital signal D1, the upper level is reached anyway. This situation is now a favorable moment to pause the detection of the signals from the first analog signal transmitter, and two temperature signals T1, T2 are then detected by the second analog signal transmitter. This is sufficient to perform the temperature measurement redundantly, so that it is subsequently detected with M7, M8, M9 that the maximum is reached during the period, so that a falling edge is present in M10, M1, M12, and the digital signal D1 falls back to the lower value at time M12. The measurement values ​​M13, M14 to M25 are then obtained at a regular interval, without pause.

[0057] A period such as that represented in the signal D1 of [Fig. 2] below and also in [Fig. 3] is typically the sign of the passage of a tooth followed by an interdental gap of the pulse wheel 3 in front of the Hall effect TC in the first analog signal transmitter 5. It is therefore preferable that, in the basic state, the measurement points be taken several times over a partial period of rotation of the rotating element with respect to a tooth. For example, the objective may be to take 15 to 16 measurements here, so it is necessary, for example, to multiply the number 16 by the number of teeth to determine the number of measurements per revolution of the pulse wheel 3. The timing of the measurement of the measurement points M1, M2, M3 and also T1, T2, etc. can be planned in a constant manner and oriented for example on a maximum rotation speed of the impulse wheel 3, or it can also be adapted several times.

[0058] The temperature values ​​T1, T2 or an average value of the two, or the most plausible value, are now recorded in memory 9 of sensor unit 4. Measuring the temperature over the lifetime of the motor vehicle or at least of sensor unit 4 yields the following profile as shown in [Fig.4]:

[0059] The bar chart shows, for example, a duration of 10 hours for the temperature range of -40 °C, 30 hours for the range around -35 °C, 50 hours for the range around -25 °C, etc. The maximum range is around +95 °C (1,500 hours). It should be taken into account that the temperature inside the motor vehicle is higher than the ambient temperature, namely due to the operation of the drive motor and friction in the drivetrain.

[0060] Such information then makes it possible to optimize the mechanics and / or, where appropriate, the electronics in the motor vehicle, in particular the sensor unit 4 itself.

[0061] The advantages of the measures according to the invention are as follows:

[0062] 1. Integrated temperature detection: synchronization of the detection of Temperature measurement combined with distance or movement and / or speed measurement allows for the integration of an additional sensor that operates without affecting the primary function. This enables continuous monitoring of ambient temperature.

[0063] 2. Optimal use of resources: the invention makes efficient use of the unit The existing computing / data processing device 6, which is usually designed as a microcontroller, and the integrated analog-to-digital converter 8 are used, without the need for additional hardware. This saves costs and space and reduces energy consumption.

[0064] 3. Detection of ambient conditions: systematic data acquisition Temperature monitoring over the lifetime of the sensor unit provides valuable information for analyzing and optimizing the entire system. This is particularly useful in extreme environments where the sensor unit, along with its two analog signal transmitters, is exposed to high temperatures and mechanical stresses.

[0065] 4. Improving system reliability: detecting and analyzing profiles of Temperature, as shown in [Fig. 4], can increase the reliability and lifespan of the sensor unit. Early signs of overheating and other environmental problems can be detected, and appropriate measures can be taken.

[0066] 5. No alteration of the primary function: the temperature measurement is carried out in such a way as not to alter the primary function of measuring displacement or path and / or speed. This is achieved by the strategic placement of temperature measurements (T1, T2) in the scanning cycles (M1 - M4, M7 and following).

[0067] 6. Profitability, because there are no additional material costs, except for the if applicable, of the temperature sensor 7.

[0068] Overall, the example shows how a sensor for path or displacement detection and / or speed with integrated temperature profile detection can be made available with limited resources.

[0069] List of reference numbers

[0070] 1 Vehicle

[0071] 2 Drive shaft

[0072] 3 Impulse wheel

[0073] 4 Sensor Unit

[0074] 5 First transmitter of analog signals

[0075] 6 Calculation unit

[0076] 7 Second analog signal transmitter, temperature sensor

[0077] 8 Analog-to-digital converter

[0078] 9 Memory

[0079] DI Digital Signal

[0080] M1-M4 Measurement signal

[0081] M7-M25 Measurement signal

[0082] SI Signal

[0083] S2 Signal

[0084] Temperature Signal

[0085] T2 Temperature Signal

Claims

Demands

1. Sensor unit (4), comprising: - a first analog signal transmitter (5) for supplying measurement signals (SI) which are generated by a rotating element (3); - a second analog signal transmitter (7) for supplying measurement signals (S2) at a temperature, in particular at a temperature relative to the rotating element (3); - a data processing device, in particular a microcontroller (6);and - an interface (8) through which the data processing device (6) is coupled to both the first analog signal transmitter (5) and the second analog signal transmitter (7), in which the data processing device (6) is designed, in a basic state, to query, via the interface (8), only the measurement signals (S1) provided by the first analog signal transmitter (5) and to query, via the interface, the temperature-related measurement signals (S2) provided by the second analog signal transmitter at a specified time which is determined according to a signal curve of the measurement signals which the data processing device (6) received from the first analog signal transmitter (5) during the query.

2. Sensor unit (4) according to claim 1, wherein the data processing device (6) is designed to perform the polling in the basic state several times over half a period of the period defined by the rotating element, in particular the period defined by a sequence of teeth on the rotating element, preferably over a quarter of this defined period.

3. Sensor unit (4) according to claim 1 or 2, wherein the data processing device (6) is designed to make the polling of measurement signals from the second analog signal transmitter (7) so short that a complete digital signal (Dl) can nevertheless be calculated for the signals (SI) from the first analog signal transmitter (5).

4. Sensor unit according to any one of claims 1 to 3, in which the first analog signal transmitter includes a magnetic sensor, preferably a magnetic sensor using the Hall effect.

5. Sensor unit (4) according to any one of claims 1 to 4, comprising a single analog-to-digital converter (8) in the interface or in the form of an interface, which can be controlled by the data processing device (6) and which is mounted and designed so that, according to the control, it sends optionally the measurement signals from the first analog signal transmitter (5) or from the second analog signal transmitter (7) to the data processing device (6).

6. Sensor unit (4) according to any one of claims 1 to 5, wherein the data processing device is designed to perform an analysis of measurement signals from the first analog signal transmitter which were received from it on the basis of at least the last two polls.

7. Sensor unit (4) according to any one of claims 1 to 6, wherein the data processing device is designed to, after detection of a beginning of flank in the trajectory of the measurement signals from the first analog signal transmitter (5), perform a temperature interrogation from the second analog signal transmitter (7) under predetermined conditions.

8. Motor vehicle (1) with a shaft, in particular a drive shaft (2), on which is mounted a rotating element, in particular a pulse wheel (3), and with the sensor unit (4) according to any one of claims 1 to 7, wherein the first analog signal transmitter (5) detects measurement signals for the rotation of this rotating element on the shaft.

9. Motor vehicle (1) according to claim 8, wherein the sensor unit (4) is designed to also detect the temperature regularly when the shaft is not rotating.

10. Motor vehicle (1) according to claim 8 or 9, comprising a memory (9) in the sensor unit (4), in which temperature measurement values ​​are stored.

11. Method of operating a sensor unit (4), wherein, on the one hand, a first analog signal transmitter (5) for supplying measurement signals to a rotating element (3) and, on the other hand, a temperature transmitter as a second analog signal transmitter (7) share a common interface (8) with a data processing device (6), wherein the data processing device (6) first queries measurement signals relating to this rotating element (3) from the first analog signal transmitter (5) and, depending on the signal profile of these measurement signals, provides a pause during which the data processing device (6) queries measurement signals from the temperature sensor (7).

12. A method according to claim 11 wherein the measurement signal from the temperature sensor (7) is repeatedly polled and the corresponding data is stored in a memory (9).

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