Device and method for evaluating the fill level of a coolant in a coolant container

Abstract

A device for evaluating the fill level of a coolant in a coolant reservoir, particularly in a vehicle, is proposed, wherein the device comprises a sensor configured to output a sensor signal, the sensor signal having a first value when the sensor is in contact with the coolant and a second value when the sensor is not in contact with the coolant, the first value being different from the second value, wherein the device comprises a processing unit configured to receive the sensor signal and determine a frequency with which the sensor signal exhibits the second value, and wherein the processing unit is further configured to output an evaluation of the coolant fill level based on the determined frequency of the second value.

Description

DESCRIPTION OF THE INVENTIONThe present invention relates to a device for detecting the level of a coolant in a coolant container, in particular a coolant container in a vehicle, according to the preamble of claim 1.In various technical systems, in particular also in vehicles, cooling circuits with coolant are used to cool various elements. These include, for example, high-voltage accumulators or internal combustion engines. The cooling circuits used usually have a coolant container.If the coolant container has a leak and thereby loses coolant, or if the cooling circuit loses coolant elsewhere, the fill level of the coolant in the coolant container may decrease. A decrease in the coolant can no longer ensure cooling, which in the worst case can lead to a failure of the cooled parts or at least to damage to these parts. In the case of a high-voltage accumulator, there is additionally the risk that the coolant (in this case water) can escape from the coolant container or cooling circuit into the high-voltage accumulator and an undesired chemical reaction can occur there, which can cause, for example, oxyhydrogen to form.In order to detect such a leakage of the coolant container or of the entire cooling circuit, it is known to monitor the fill level of the coolant container and to output a warning if a predefined minimum quantity of coolant falls below a critical level.To date, simple fill level sensors have been used here, for example for a coolant compensation container, which measure a voltage value via two pins. If a critical threshold is undershot, the measured voltage changes significantly, with the result that evaluation electronics with a certain attenuation (in order, for example, to compensate for fluctuations in the fill level as a result of sloshing of the liquid) trigger an alarm. However, these simple 2-pin sensors can only detect a threshold being exceeded or undershot, but not how far the fill level is still away from the threshold. Furthermore, more complex measuring systems are known which measure the fill level not only by means of threshold monitoring, but continuously measure the fill level, for example via the movement of a float. However, these more complex measurement systems are expensive.The present invention is therefore based on the object of providing a favorable possibility for more accurately monitoring the fill level of a coolant in a coolant container.This object is achieved by a device for detecting the fill level of a coolant in a coolant container according to patent claim 1 and a method for detecting the fill level of a coolant in a coolant container according to patent claim 9.The device is provided in particular for evaluating a fill level of a coolant in a coolant container in a vehicle.The coolant may be any coolant that may be used in a vehicle. For example, the coolant may be a coolant of a cooling circuit for cooling an internal combustion engine or for cooling a high-voltage accumulator of a vehicle. The coolant container in which the coolant is located can be a coolant container used in such cooling circuits, for example also a coolant compensation container. The coolant may move in the coolant reservoir due to movements of, for example, the vehicle. The fill level of the coolant can therefore change on the one hand on account of an actual decrease in the coolant (in this case permanently) and on the other hand on account of such movements (in this case only provisionally).The device therefore has a sensor which is designed to output a sensor signal which has a first value when the sensor is in contact with the coolant and a second value when the sensor is not in contact with the coolant. The first value and the second value differ from one another. The sensor may be any sensor, e.g., a 2-pin sensor or 2-wire sensor, which outputs different values upon contact or non-contact with the coolant.For example, the sensor may correspond to a switch that is closed by contact with the coolant and therefore has a low resistance and that is open in the absence of contact with the coolant and therefore has a high resistance. The sensor can therefore output a low voltage as the first value in the first case and a significantly higher voltage as the second value in the second case.In contrast to previous systems, in order to now achieve a more accurate monitoring of the fill level, which goes beyond a mere detection of the exceeding or falling below a threshold value, the device has a processing unit which is designed to receive the sensor signal and to determine a frequency with which the sensor signal has the second value, i.e. the value in the case of non-contact of the sensor with the coolant.If the fill level of the coolant changes and falls, in particular, to a fill level at which the sensor no longer makes contact with the coolant, the sensor signal will have the second value. If the fill level of the coolant is at a level around the position of the sensor, the fill level can fluctuate due to movements of the coolant container and thus movements of the coolant and the coolant can come into contact with the sensor more frequently or less frequently. In this case, the first and second values may alternate.In previous systems, it was only determined whether and how long a threshold value is exceeded. In this way, it was possible to ignore single brief exceeds of the threshold value, but a further more accurate determination of the fill level was not possible with the systems hitherto.In contrast, a more accurate assessment of the fill level is made possible by the present device, since the processing unit recognizes how frequently the second value of the sensor signal occurs and how frequently the sensor does not have any contact with the coolant therewith. This information can be used by the processing unit to assess the fill level of the coolant in the coolant container and to output this assessment. At the same time, a very simple sensor can be used which gives only an indication of contact or non-contact with the lubricant.The processing unit may output the assessment to a user, e.g., a driver or occupant of the vehicle, e.g., via a screen. Alternatively, the processing unit can also pass the information or evaluation on to further units or devices of the vehicle, which in turn can use this information in order to take or initiate further actions. This can be, for example, a stopping of the vehicle or throttling of the engine or the like in order to prevent damage to the elements to be cooled.According to one specific embodiment, the processing unit is designed to determine the frequency with which the sensor signal has the second value over a predefined period of time. In this way, it can be ensured that not only a short-term dry-state of the sensor is detected, but rather a plurality of such events occur over a specific period of time, which events are indicated by the sensor by outputting the second value. The more frequently the sensor outputs the second value within the predefined period of time, the more likely the sensor is to be dry and thus a critical fill level of the coolant, as explained below.Furthermore, the processing unit may also take into account a duration of the second value in addition to the frequency of the second value. If the second value occurs more and more frequently and longer, for example, this can likewise indicate a high probability that a critical fill level of the coolant has been reached.Furthermore, the processing unit may be configured to calculate a gradient via an increase in the frequency of the second value over the predefined period of time. With this gradient, a time can again be determined which still remains until the critical fill level is undershot. If this time is below a threshold to be defined (e.g. two weeks), a corresponding warning is output by the processing unit.According to a further embodiment, the evaluation of the fill level of the coolant comprises a statement about a sufficient fill level, a deficient fill level or an insufficient fill level. When a sufficient fill level is present, enough coolant is present in the coolant container so that proper operation can be ensured. Furthermore, in the case of a sufficient fill level, it is to be assumed that no leak is present in the coolant container or the cooling circuit, as a result of which the fill level would decrease.In the case of a deficient fill level, sufficient coolant is still present in the coolant container so that proper operation can be ensured, but in this case the fill level has already decreased to such an extent that coolant should be replenished. Furthermore, if the fill level is deficient, there is the risk that proper operation is no longer possible in the near future and possibly further parts which are cooled can be damaged. In addition, a poor level may indicate that there is a leak in the coolant reservoir or the cooling circuit, and therefore should be checked and checked.In the case of an inadequate fill level, although coolant may still be present in the coolant container, this has already reached a critical threshold, so that proper operation may no longer be ensured. In this case, it can be checked, on the one hand, whether a leak is present in the coolant container or the cooling circuit. On the other hand, suitable measures such as filling up the coolant container or possibly also stopping the vehicle should be taken.According to a further embodiment, the processing unit is configured to determine whether the frequency of the second value exceeds a first threshold value or a second threshold value. In particular, the first threshold value may correspond to a pre-warning threshold and the second threshold value may correspond to a critical threshold. The first threshold value corresponds to a lower frequency of occurrence of the second value than the second threshold value. As described above, the pre-warning threshold may correspond to a deficient fill level, which may be an indication of a loss of coolant, for example. The critical threshold may correspond to an insufficient fill level.According to a further embodiment, the processing unit is configured to determine, based on the determined frequency, a probability with which the fill level of the coolant corresponds to the pre-warning threshold and / or the critical threshold.The closer the fill level is to the critical threshold, the more frequently the sensor signal will have the second value. The more frequently the second value is present, the higher the probability that the pre-warning threshold is reached. If the second value is present even more frequently, the probability is higher that the critical threshold has already been reached. Any number of gradations between the sufficient fill level and the pre-warning threshold or the critical threshold can be defined.Furthermore, the probability can be determined depending on the application. If the device is to warn early, the processing unit can establish a high probability of the pre-warning threshold already at a low frequency of the second value. If, on the other hand, the device is to warn only late, the processing unit can establish a high probability at a high frequency of the second value. This applies analogously to the critical threshold.According to a further embodiment, the device has one or more further sensors for determining the acceleration of the vehicle, wherein the processing unit is designed to take the acceleration of the vehicle into account in the evaluation of the fill level of the coolant.In this way, in addition to the fluctuations of the coolant detected by the sensor by changing values of the sensor signal, the fluctuations in the fill level occurring, for example, in a vehicle during travel due to transverse and longitudinal acceleration forces can also be utilized. As already described above, the closer the fill level is to the critical threshold, the more frequently the sensor signal has the second value. Since, in this embodiment, the processing unit also has access to data from the acceleration sensors in the vehicle, the processing unit can determine a model for the actual fill level on the basis of this information about the acceleration and the sensor signal. The processing unit can use machine learning algorithms or neural networks, for example, to create the model.The processing unit can determine the probability of reaching the pre-warning threshold, for example, on the basis of the following rules:1) The more frequently the sensor signal has the second value, the higher the probability that the pre-warning threshold is reached;2) The lower the accelerations at which the second value occurs, the higher the probability that the pre-warning threshold is reached.According to a further embodiment, the device has one or more further sensors for determining an inclination of the vehicle. The inclination of the vehicle, and thus of the coolant container, can also have an influence on the contact of the sensor with the coolant and thus on the sensor signal. According to this embodiment, the processing unit can therefore be configured to take into account the inclination of the vehicle when assessing the fill level of the coolant. This can preferably be done in combination with the acceleration.According to a further embodiment, the processing unit is configured to take into account information regarding the shape of the coolant container and / or the position of the sensor in the coolant container when evaluating the fill level of the coolant. Depending on the shape of the coolant container and / or the position of the sensor in the coolant container, the sensor may or may not be in contact with the coolant in the event of different fluctuations in the fill level. In particular, if the sensor is arranged asymmetrically, in the case of corresponding movements or positions of the vehicle, caused for example by transverse and / or longitudinal acceleration forces or by an inclination of the vehicle, the sensor can still be in contact with the coolant, even though a critical threshold or pre-warning threshold has already been reached, or can no longer be in contact with the coolant, even though the fill level is sufficient. By evaluating the fill level based both on the sensor signal or the frequency of the second value of the sensor signal and further information such as the position of the sensor, the acceleration of the vehicle and / or the inclination of the vehicle, an accurate and comprehensive evaluation of the fill level is thus possible.According to a further aspect, a method for evaluating a fill level of a coolant in a coolant container, in particular in a vehicle, is proposed. The method comprises the following steps: outputting a sensor signal from a sensor, wherein the sensor signal has a first value when the sensor is in contact with the coolant and has a second value when the sensor is not in contact with the coolant, wherein the first value differs from the second value, receiving the sensor signal, determining a frequency at which the sensor signal has the second value, and outputting an evaluation of the fill level of the coolant based on the determined frequency of the second value.The embodiments and features described for the proposed device apply correspondingly to the proposed method.Furthermore, a computer program product is proposed, which has a program code which is designed to cause a computer to carry out the method as explained above.A computer program product, such as a computer program means, can be provided or supplied, for example, as a storage medium, such as a memory card, USB stick, CD-ROM, DVD, or else in the form of a downloadable file from a server in a network. This can be effected, for example, in a wireless communication network by the transmission of a corresponding file with the computer program product or the computer program means.Further possible implementations of the invention also include combinations, not explicitly mentioned, of features or embodiments described above or below with respect to the exemplary embodiments. In this case, the person skilled in the art will also add individual aspects as improvements or additions to the respective basic form of the invention.Further advantages and advantageous embodiments are specified in the description, the drawings and the claims. In this case, in particular the combinations of the features indicated in the description and in the drawings are purely exemplary, and therefore the features can also be present individually or in a different combination.The invention will be described in more detail below with reference to exemplary embodiments illustrated in the drawings. The exemplary embodiments and the combinations shown in the exemplary embodiments are purely exemplary and are not intended to define the scope of protection of the invention. This is defined solely by the appended claims.The following are shown: FIG. 1 : shows a schematic block diagram of a device for evaluating a fill level of a coolant; and FIG. 2 : shows a schematic view of a vehicle with the device from FIG. 1.FIG. 1 shows a device 1 for evaluating a fill level F 1, F 2, F 3 of a coolant 4 in a coolant container 2.The coolant 4 in the coolant container 2 can be monitored by a sensor 6. The sensor 6 is preferably arranged in such a way that it is in contact with the coolant 4 in a sufficient fill level F 1 of the coolant 4 and is not in contact with the coolant 4 in an insufficient fill level F 3. In a fill state F 2 in which sufficient coolant 4 is still present but a pre-warning threshold is already reached, the sensor 6 will sometimes be in contact with the coolant 4 and sometimes not depending on movements of the coolant 4 that may be caused by movements of the vehicle 20.This alternating contact of the sensor 6 with the coolant 4 is detected since the sensor 6 outputs a sensor signal 8 which has a first value when the sensor 6 is in contact with the coolant 4 and has a second value when the sensor 6 is not in contact with the coolant ( 4). The first value and the second value are different, for example, the first value may be a low voltage and the second value may be a high voltage.In order to now carry out an evaluation of the fill level F 1, F 2, F 3 of the coolant 4 on the basis of the sensor signal 8, the device 1 has a processing unit 10. The processing unit 10 may be part of a control or computing system of the vehicle 20, for example.The processing unit 10 receives the sensor signal 8 and determines a frequency with which the sensor signal 8 has the second value. Based on the determined frequency of the second value, the processing unit 10 can subsequently output (12) an evaluation of the fill level F1, F2, F3of the coolant 4.The processing unit 10 preferably receives further sensor signals from sensors 14- 1,... in addition to the sensor signal 8. 14-n. These sensors 14-1,... 14- nmay be various sensors, for example of the vehicle, which contain information about a longitudinal and / or lateral acceleration, inclination or angle of inclination of the vehicle 20. This information can additionally be used to perform the evaluation of the fill level F 1, F 2, F 3.The processing unit 10 may further receive information 18 regarding the position of the sensor 6 in the coolant reservoir 4, the position of the coolant reservoir 4 in the vehicle 2, the shape of the coolant reservoir 4, or the like. This information 18 may be retrieved from, for example, a database 16, which may be part of the vehicle 20 or which is implemented on a server.The processing unit 10 is configured in particular to assess whether the fill level of the coolant 4 is in a sufficient fill level F 1, a fill level F 2 corresponding to a pre-warning threshold or a critical fill level F 3.For this purpose, the processing unit 10, as described above, determines the frequency with which the sensor signal 8 assumes the second value. In contrast to previous systems, in which it was only determined whether the sensor 6 exceeds or falls below a threshold value, the processing unit 10 can also detect fluctuations / movements of the coolant 4 by determining the frequency of the second value and take them into account when evaluating the fill level. In the case of severe fluctuations or movements, if the fill level has actually already reached the pre-warning threshold F 2, the second value will occur more frequently than if the fill level is still sufficient (F 1). If, on the other hand, the critical threshold F 3 has already been reached, the second value of the sensor signal 8 will occur even more frequently.If the sensor 8 is mounted asymmetrically, e.g. on the left side of the container 2, as shown by way of example in FIG. 1, for example in the case of a right-hand turn of the vehicle 20, the sensor 6 can lie dry due to the corresponding fluctuation of the coolant 4, even though the fill level F 1 is sufficient. In contrast thereto, for example, the sensor 6 can be in contact with the coolant 4 during a left turn of the vehicle 20, even though the fill level has already reached the pre-warning threshold F 2. If, therefore, the processing unit 10 receives not only the sensor signal 8, but also further additional information from sensors 14, 14- 1... 14- n, the evaluation of the fill level F 1, F 2, F 3 can be further improved.In summary, the device described here makes it possible to evaluate the fill level of a coolant in a coolant container, which is substantially more comprehensive and accurate than previous systems. Furthermore, the described device is capable of taking into account and compensating movements and fluctuations of the coolant during the evaluation.Reference numerals denote reference numerals1 Device 2 Coolant container 4 Coolant 6 Sensor 8 Sensor signal 10 Processing unit 12 Output signal 14, 14-1, 14-2 Acceleration sensors, inclination sensors 16 Database 18 Further information F 1 Sufficient fill level F 2 Insufficient fill level (pre-warning threshold) F 3 Insufficient fill level (critical threshold)

Claims

Device (1) for evaluating a fill level (F1, F2, F3) of a coolant (4) in a coolant container (2), in particular in a vehicle (20), wherein the device (1) has a sensor (6) which is designed to output a sensor signal (8), wherein the sensor signal (8) has a first value when the sensor (6) contacts the coolant (4) and has a second value when the sensor (6) does not contact the coolant (4), wherein the first value differs from the second value, characterized in that the device (1) has a processing unit (10) which is designed to receive the sensor signal (8) and to determine a frequency at which the sensor signal (8) has the second value, wherein the processing unit (10) is furthermore designed to, based on the determined frequency of the second value, an evaluation of the fill level (F1, F2, F3) of the coolant (4) is to be output.The device according to claim 1, wherein the processing unit (10) is configured to determine the frequency with which the sensor signal (8) has the second value over a predefined period of time.Device according to claim 1 or 2, wherein the evaluation of the fill level (F1, F2, F3) of the coolant (4) comprises a statement about a sufficient fill level (F1), a deficient fill level (F2) or an insufficient fill level (F3).The device according to any of the preceding claims, wherein the processing unit (10) is configured to determine whether the frequency of the second value exceeds a first threshold value or a second threshold value.The apparatus of claim 4, wherein the first threshold corresponds to a pre-warning threshold (F2) and wherein the second threshold corresponds to a critical threshold (F3).Device according to one of the preceding claims, wherein the processing unit (10) is designed to determine, based on the determined frequency, a probability with which the fill level (F1, F2, F3) of the coolant (4) corresponds to the pre-warning threshold (F2) and / or the critical threshold (F3).Device according to one of the preceding claims, wherein the device (1) has one or more further sensors (14, 14-1, 14-n) for determining the acceleration of the vehicle (20), and wherein the processing unit (10) is designed to take account of the acceleration of the vehicle (20) in the evaluation of the fill level (F1, F2, F3) of the coolant (4).Device according to one of the preceding claims, wherein the device (1) has one or more further sensors (14, 14-1, 14-n) for determining an inclination of the vehicle (20), and wherein the processing unit (10) is designed to take account of the inclination of the vehicle (20) in the evaluation of the fill level (F1, F2, F3) of the coolant (4).Device according to one of the preceding claims, wherein the processing unit (10) is configured to take into account information relating to the shape of the coolant container (2) and / or the position of the sensor (6) in the coolant container when evaluating the fill level (F1, F2, F3) of the coolant (4).Method for evaluating a fill level (F1, F2, F3) of a coolant (4) in a coolant container (2), in particular in a vehicle (20), wherein the method comprises the output of a sensor signal (8) from a sensor (6), wherein the sensor signal (8) has a first value when the sensor (6) contacts the coolant (4) and has a second value when the sensor (6) does not contact the coolant (4), wherein the first value differs from the second value, characterized in that the method comprises the following steps: receiving the sensor signal (8), determining a frequency at which the sensor signal (8) has the second value, and outputting an evaluation of the fill level (F1, F2, F3) of the coolant (4) based on the determined frequency of the second value.

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