Sensor device for detecting an electrically conductive medium and method for operating a sensor device

Abstract

Sensor device (10) for detecting an electrically conductive medium, in particular a liquid, in a control unit (1) of a motor vehicle, comprising a sensor element (12) and a test unit (14), wherein the sensor element (12) is electrically connected to the test unit (14), wherein the test unit (14) has a signal transmitter (16) connected to the sensor element (12) and a signal receiver (18) connected to the sensor element (12), wherein the signal transmitter (16) is configured to generate an electrical test signal (T), wherein the signal receiver (18) is configured to detect a reaction signal (R) to the electrical test signal (T), wherein the test unit (14) is configured to detect an interruption of an electrical connection between the sensor element (12) and the test unit (14), wherein the sensor element (12) has a first sensor ring (12a) and a second sensor ring (12b),wherein the first sensor ring (12a) is connected to the test unit (14) by a first electrical line (20) and a second electrical line (22), and wherein the second sensor ring (12b) is connected to the test unit (14) by a third electrical line (26) and a fourth electrical line (28), characterized in that the sensor element (12) has at least one component (24) designed as a capacitor, which connects the first sensor ring (12a) and the second sensor ring (12b).

Description

[0001] The invention relates to a sensor device for detecting a conductive medium, in particular a liquid, in a control unit of a motor vehicle. Furthermore, the invention relates to a control unit, a steering system, and a method for operating a sensor device. State of the art

[0002] Sensor devices and methods for operating them are already known from the prior art. For water detection, it is known to use two electrically conductive sensor elements to determine whether they are electrically connected by the water. For example, if the two sensor elements are submerged in water and one of the sensor elements is connected to a predetermined electrical potential, it can be determined whether the other sensor element adopts the electrical potential of the other sensor element.

[0003] However, if water ingress into a control unit of a motor vehicle is to be reliably detected, it may happen that the sensor device itself is faulty, e.g. that there is an interruption in an electrical line in the sensor device and that the sensor device is therefore unable to detect water ingress into the control unit.

[0004] Especially for use in steering systems or braking systems of autonomous vehicles, it is therefore of great importance to provide redundant systems on the one hand and to identify and detect all possible causes of failure of the control unit on the other.

[0005] There is therefore a need, in addition to providing a sensor device for detecting water ingress into the control unit of the motor vehicle, to also monitor the functionality of the sensor device itself.

[0006] In this context, for example, KR 10 2006 0 008 522 A and JP 2002-111 468 A disclose a sensor device for detecting an electrically conductive medium, by means of which an interruption of an electrical connection between a sensor element and a test unit can be detected.

[0007] The invention is therefore based on the object of providing an improved sensor device for detecting an electrically conductive medium in a control unit of a motor vehicle, in which a failure of electrical connecting elements can be detected.

[0008] The object is achieved with a sensor device for detecting an electrically conductive medium in a control unit of a motor vehicle having the features of patent claim 1. The object is further achieved with a control unit having the features of patent claim 5. The object is further achieved with a steering system having the features of patent claim 6 and with a method for operating a sensor device having the features of patent claim 7. Disclosure of the invention

[0009] The present invention provides a sensor device for detecting an electrically conductive medium, in particular a liquid, in a control unit of a motor vehicle, comprising a sensor element and a test unit, wherein the sensor element is electrically connected to the test unit, wherein the test unit has a signal transmitter connected to the sensor element and a signal receiver connected to the sensor element, wherein the signal transmitter is configured to generate an electrical test signal, wherein the signal receiver is configured to detect a reaction signal to the electrical test signal, and wherein the test unit is configured to detect an interruption of an electrical connection between the sensor element and the test unit, in particular based on a characteristic and / or a course of the reaction signal and / or an absence of the reaction signal.

[0010] The present invention further provides a control unit with the sensor device according to the invention and a steering system with at least one sensor device according to the invention and / or with at least one control unit according to the invention.

[0011] The present invention further provides a method for operating a sensor device, a control device or a steering system, wherein the signal transmitter is controlled to generate a test signal, and wherein a reaction signal caused by the test signal is detected by means of the signal receiver, and wherein a functionality of the sensor device or an interruption of the electrical connection between the sensor element and the test unit is determined as a function of the detected reaction signal.

[0012] One idea of the present invention is to differentiate, by providing the test unit with the functionality of detecting an interruption in an electrical connection between the sensor element and the test unit, whether a malfunction of the control unit is caused by water ingress or an interruption in the electrical connection within the sensor device. Thus, if an interruption in the electrical connection between the sensor element and the test unit should occur, this can be reliably detected and recorded by the control unit, allowing the control unit to generate a corresponding warning.

[0013] This can prevent the situation where water ingress into the control unit cannot be detected due to an interruption in the electrical connection in the sensor device. The sensor device according to the invention is thus capable of reliably detecting both water ingress and an interruption in the electrical connection within the sensor device. This contributes to increasing the safety of control units in, for example, steering systems or braking systems for autonomous vehicles.

[0014] Advantageous embodiments and further developments emerge from the subclaims and from the description with reference to the figures.

[0015] According to a preferred development, the electrical test signal generated by the signal generator triggers a first response signal if the sensor device is functioning properly, and a second response signal if at least one electrical line is interrupted. When the test signal or a test pulse is applied to the sensor element, the test signal is modified according to a characteristic of the component, so that a different response signal is generated if the sensor device is functioning properly than if the electrical line is interrupted.

[0016] In this case, the sensor element is connected to the test unit by several electrical lines, wherein the sensor element has at least one component in the form of a capacitor. The provision of the component, in particular the capacitor, on the sensor element advantageously makes it possible to prevent the physical values of the component from being measured, thus making it possible to detect an interruption in an electrical connection.

[0017] According to a further preferred development, it is provided that, if the sensor device is functional, the electrical test signal generated by the signal generator can be modified by the component, in particular the capacitor, and wherein, if the at least one electrical line is interrupted, the electrical test signal generated by the signal generator cannot be modified by the component, in particular the capacitor. If there is an interruption in the electrical line, the test signal is not applied to the component and is therefore modified by it, whereby a failure or malfunction of the electrical line of the sensor device can advantageously be detected.

[0018] In the present case, the sensor element comprises a first sensor ring and a second sensor ring, wherein at least the component, in particular the capacitor, connects the first sensor ring and the second sensor ring. Since an electrical line is connected to the first sensor ring and another electrical line is connected to the second sensor ring, it is therefore expedient to install the component, in particular the capacitor, between the first sensor ring and the second sensor ring in order to advantageously achieve the inventive effect of detecting the line interruption.

[0019] Furthermore, the first sensor ring is connected to the test unit by a first electrical line and a second electrical line, and the second sensor ring is connected to the test unit by a third electrical line and a fourth electrical line. Providing a multi-wire connection with a total of four connecting lines on the respective sensor rings has the advantage that an interruption of the electrical connection of each individual sensor ring can be detected.

[0020] According to a further preferred development, the signal transmitter is configured to feed the test signal into the first electrical line and the third electrical line, and the signal receiver is configured to receive the response signal through the second electrical line and the fourth electrical line. The signal receiver is thus advantageously configured to feed the test signal into the respective connection to one of the sensor rings and to receive the corresponding response signal.

[0021] According to a further preferred development, if the sensor device is functional, the test signal fed into the first electrical line and the third electrical line corresponds to the response signal received by the signal receiver via the second electrical line and the fourth electrical line. Because no modification of the test signal is performed, the response signal advantageously corresponds to the test signal if the sensor device is functional.

[0022] According to a further preferred development, it is provided that in the event of an interruption of the first and / or second electrical line, the signal receiver receives no reaction signal through the second electrical line, and wherein in the event of an interruption of the third and / or fourth electrical line, the signal receiver receives no reaction signal through the fourth electrical line. If no reaction signal is received through the second electrical line, a line interruption in the region of the first sensor ring or its connections can thus advantageously be detected, and if no reaction signal is received from the fourth electrical line, an interruption of the electrical connection in the region of the second sensor ring and its connections can advantageously be detected.

[0023] According to the invention, the sensor element thus has a first sensor ring and a second sensor ring, wherein the first sensor ring is connected to the test unit by a first electrical line and a second electrical line, wherein the second sensor ring is connected to the test unit by a third electrical line and a fourth electrical line, and wherein the sensor element has at least one component in the form of a capacitor. In the present embodiment, the sensor device thus has four electrical lines and one component, so that connection interruptions can advantageously be detected even more precisely. By using test pulses, a combined evaluation of both the connection lines and the component can be carried out.

[0024] According to a further preferred development, it is provided that the signal generator is designed to feed the test signal into the first electrical line and the third electrical line, wherein the signal receiver is designed to receive the reaction signal through the second electrical line and the fourth electrical line, wherein when the test signal is fed into the first electrical line, in the case of the functionality of the sensor device, the electrical test signal generated by the signal generator can be modified by the component, in particular the capacitor, and can be received by the signal receiver through the fourth electrical line, and wherein an unmodified test signal can additionally be received by the signal receiver through the second electrical line.

[0025] According to a further preferred development, it is provided that when the test signal is fed into the third electrical line, in the event of the sensor device being functional, the electrical test signal generated by the signal generator can be modified by the component, in particular the capacitor, and can be received by the signal receiver through the second electrical line, and wherein an unmodified test signal can additionally be received by the signal receiver through the fourth electrical line.

[0026] If there is an interruption in the electrical line, the test signal is not applied to the component and is therefore modified by it, advantageously detecting a failure or malfunction of the electrical line of the sensor device. The signal receiver is also advantageously configured to feed the test signal into the respective connection to one of the sensor rings and to receive the corresponding response signal.

[0027] The described designs and further training courses can be combined as desired.

[0028] Further possible embodiments, developments and implementations of the invention also include combinations of features of the invention described previously or below with regard to the exemplary embodiments that are not explicitly mentioned. Short description of the drawings

[0029] The accompanying drawings are intended to provide a further understanding of embodiments of the invention. They illustrate embodiments and, in conjunction with the description, serve to explain principles and concepts of the invention.

[0030] Other embodiments and many of the aforementioned advantages will become apparent upon review of the drawings. The elements illustrated in the drawings are not necessarily drawn to scale.

[0031] They show: Fig. 1 a schematic representation of a sensor device for detecting an electrically conductive medium in a control unit of a motor vehicle according to a preferred embodiment of the invention; Fig. 2 shows a representation of a signal form of a test signal and a reaction signal of the sensor device in the case of functionality of the sensor device according to the preferred embodiment of the invention; Fig. 3 is a representation of a signal waveform of a test signal and a reaction signal of the sensor device in the event of an interruption of an electrical connection of the sensor device according to the preferred embodiment of the invention; Fig. 4 a schematic representation of the sensor device for detecting the electrically conductive medium in the control unit of the motor vehicle according to a further preferred embodiment of the invention; Fig. 5 a schematic representation of the sensor device for detecting the electrically conductive medium in the control unit of the motor vehicle according to a further preferred embodiment of the invention; and Fig. 6 a flowchart of a method for operating the sensor device according to the preferred embodiment of the invention.

[0032] In the figures of the drawings, the same reference symbols designate the same or functionally identical elements, parts or components, unless otherwise stated.

[0033] Fig. 1 shows a schematic representation of a sensor device for detecting an electrically conductive medium in a control unit of a motor vehicle according to a preferred embodiment of the invention.

[0034] The sensor device 10 for detecting the electrically conductive medium, in particular the liquid, in the control unit 1 of the motor vehicle has a sensor element 12 and a test unit 14. In the present embodiment, the test unit 14 is arranged in the control unit 1. Alternatively, the test unit 14 can be arranged, for example, outside the control unit 1 and connected to the control unit 1 in a suitable manner.

[0035] The sensor element 12 is electrically connected to the test unit 14. The test unit 14 has a signal transmitter 16 connected to the sensor element 12 and a signal receiver 18 connected to the sensor element 12. The signal transmitter 16 is configured to generate an electrical test signal T. The signal receiver 18 is configured to detect a response signal R to the electrical test signal T. The test unit 14 is configured to detect an interruption of an electrical connection between the sensor element 12 and the test unit 14.

[0036] The sensor element 12 is connected to the test unit 14 via a first electrical line 20 and a second electrical line 22. The sensor element 12 further comprises a component 24. In the present embodiment, the component 24 is formed by a capacitor. Alternatively, the component 24 can be formed by a resistor, for example.

[0037] The electrical test signal T generated by the signal generator 16 causes a first reaction signal R1 in the event of a functional capability of the sensor device 10 and a second reaction signal R2 in the event of an interruption of at least one electrical line.

[0038] The sensor element 12 has a first sensor ring 12a and a second sensor ring 12b. The component 24 electrically connects the first sensor ring 12a and the second sensor ring 12b.

[0039] Fig. Figure 2 shows a representation of a signal form of a test signal and a response signal of the sensor device in the case of a functional function of the sensor device according to the preferred embodiment of the invention. The upper, in Fig. The signal waveform shown in Figure 2 is the test signal or a test pulse generated by the signal generator. The lower signal waveform shown in Figure 2 is Fig. The signal waveform shown in Figure 2 is the response signal R, i.e., the test signal modified by the component. Due to the modifiability of the test signal, this is an indication of the functionality of the sensor device.

[0040] Fig. 3 shows a representation of a signal form of a test signal and a reaction signal of the sensor device in the event of an interruption of an electrical connection of the sensor device according to the preferred embodiment of the invention. Fig. 3 The waveform shown above is as in Fig. 2 shows the test signal generated by the signal generator of the test unit. The lower, in Fig. The signal form shown in Figure 3 indicates a connection interruption of the sensor device, since this signal form is atypical for the component, in the present embodiment of the capacitor.

[0041] Fig. 4 shows a schematic representation of the sensor device for detecting the electrically conductive medium in the control unit of the motor vehicle according to a further preferred embodiment of the invention.

[0042] According to the further preferred embodiment, the sensor element 12 has a first sensor ring 12a and a second sensor ring 12b. The first sensor ring 12a is connected to the test unit 14 via a first electrical line 20 and a second electrical line 22. The second sensor ring 12b is connected to the test unit 14 via a third electrical line 26 and a fourth electrical line 28.

[0043] The signal generator 16 is configured to feed the test signal T into the first electrical line 20 and the third electrical line 26. The signal receiver 18 is configured to receive the response signal R through the second electrical line 22 and the fourth electrical line 28.

[0044] If the sensor device 10 is functional, the test signal fed into the first electrical line 20 and the third electrical line 26 corresponds to the response signal received by the signal receiver 18 through the second electrical line 22 and the fourth electrical line 28, since no modification of the signal is carried out.

[0045] In the event of an interruption of the first and / or second electrical line 20, 22, the signal receiver 18 does not receive a response signal R through the second electrical line 22. In the event of an interruption of the third and / or fourth electrical line 26, 28, the signal receiver 18 does not receive a response signal R through the fourth electrical line 28.

[0046] The test unit 14 is thus configured to detect an interruption of an electrical connection between the sensor element 12 and the test unit 14 based on the reaction signal R or the absence of the reaction signal R.

[0047] Fig. 5 shows a schematic representation of the sensor device for detecting the electrically conductive medium in the control unit of the motor vehicle according to a further preferred embodiment of the invention.

[0048] The sensor element 12 has a first sensor ring 12a and a second sensor ring 12b. The first sensor ring 12a is connected to the test unit 14 via a first electrical line 20 and a second electrical line 22. The second sensor ring 12b is connected to the test unit 14 via a third electrical line 26 and a fourth electrical line 28. The sensor element 12 has a component 24, in the present embodiment, a capacitor.

[0049] The signal generator 16 is configured to feed a test signal T into the first electrical line 20 and the third electrical line 26, wherein the signal receiver 18 is configured to receive the response signal R through the second electrical line 22 and the fourth electrical line 28.

[0050] When the test signal T is fed into the first electrical line 20, provided the sensor device 10 is functional, the electrical test signal T generated by the signal generator 16 can be modified by the component 24 and received by the signal receiver 18 via the fourth electrical line 28. An unmodified test signal T can also be received by the signal receiver 18 via the second electrical line 22.

[0051] When the test signal T is fed into the third electrical line 26, provided the sensor device 10 is functional, the electrical test signal T generated by the signal generator 16 can be modified by the component 24 and received by the signal receiver 18 via the second electrical line 22. An unmodified test signal T can also be received by the signal receiver 18 via the fourth electrical line 28.

[0052] Fig. 6 shows a flowchart of a method for operating the sensor device according to the preferred embodiment of the invention.

[0053] The signal generator 16 is controlled to generate a test signal T S1. A reaction signal R caused by the test signal T is detected S2 by the signal receiver 18. Depending on the detected reaction signal R, the functionality of the sensor device 10 or an interruption of the electrical connection between the sensor element 12 and the test unit 14 is determined S3.

Claims

[1] Sensor device (10) for detecting an electrically conductive medium, in particular a liquid, in a control unit (1) of a motor vehicle, comprising a sensor element (12) and a test unit (14), wherein the sensor element (12) is electrically connected to the test unit (14), wherein the test unit (14) has a signal transmitter (16) connected to the sensor element (12) and a signal receiver (18) connected to the sensor element (12), wherein the signal transmitter (16) is configured to generate an electrical test signal (T), wherein the signal receiver (18) is configured to detect a reaction signal (R) to the electrical test signal (T), wherein the test unit (14) is configured to detect an interruption of an electrical connection between the sensor element (12) and the test unit (14), wherein the sensor element (12) has a first sensor ring (12a) and a second sensor ring (12b),wherein the first sensor ring (12a) is connected to the test unit (14) by a first electrical line (20) and a second electrical line (22), and wherein the second sensor ring (12b) is connected to the test unit (14) by a third electrical line (26) and a fourth electrical line (28), , characterized by that the sensor element (12) has at least one component (24) designed as a capacitor, which connects the first sensor ring (12a) and the second sensor ring (12b). [2] Sensor device (10) according to claim 1, characterized by that the test signal (T) is a test pulse. [3] Sensor device (10) according to one of the preceding claims, characterized byin that the signal generator (16) is designed to feed the test signal (T) into the first electrical line (20) and into the third electrical line (26), wherein the signal receiver (18) is designed to receive the reaction signal (R) through the second electrical line (22) and the fourth electrical line (28), wherein when the test signal (T) is fed into the first electrical line (20) and the sensor device (10) is functional, the electrical test signal (T) generated by the signal generator (16) can be modified by the component (24), in particular the capacitor, and can be received by the signal receiver (18) through the fourth electrical line (28), and wherein an unmodified test signal (T) can additionally be received by the signal receiver (18) through the second electrical line (22). [4] Sensor device (10) according to one of the preceding claims, characterized bythat when the test signal (T) is fed into the third electrical line (26) in the event of the functionality of the sensor device (10), the electrical test signal (T) generated by the signal generator (16) can be modified by the component (24), in particular the capacitor, and can be received by the signal receiver (18) through the second electrical line (22), and wherein an unmodified test signal (T) can additionally be received by the signal receiver (18) through the fourth electrical line (28). [5] Control unit (1) with a sensor device according to one of claims 1 to 4. [6] Steering system with at least one sensor device (10) according to one of claims 1 to 4 and / or with at least one control unit (1) according to claim 5. [7] Method for operating a sensor device (10) according to one of claims 1 to 4, a control unit (1) according to claim 5 or a steering system according to claim 6, wherein the signal transmitter (16) is controlled to generate a test signal (T) (S1), wherein a reaction signal (R) caused by the test signal (T) is detected (S2) by means of the signal receiver (18), and wherein a functionality of the sensor device (10) or an interruption of the electrical connection between the sensor element (12) and the test unit (14) is determined (S3) as a function of the detected reaction signal (R).

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