Method for operating a power device, control device for carrying out such a method and power device with such a control device

Abstract

The invention relates to a method for operating a power device (1), wherein - the power device (1) is operated in a first predetermined operating range (B1), wherein - a first diagnostic value (D1) of a sensor (3) is detected while the power device (1) is operated in the first predetermined operating range (B1), wherein - the power device (1) is operated in a second predetermined operating range (B2) different from the first predetermined operating range (B1), wherein - a second diagnostic value (D2) of the sensor (3) is detected while the power device (1) is operated in the second predetermined operating range (B2), and wherein - a sensor behavior of the sensor (3) is evaluated based on a comparison between the first and second diagnostic values ​​(D1, D2).

Description

[0001] The invention relates to a method for operating a power device, a control device for a power device, configured to carry out such a method, and a power device having at least one sensor and such a control device operatively connected to the at least one sensor.

[0002] Power devices are usually equipped with a large number of sensors and are typically operated depending on the sensor values ​​recorded by the sensors. Therefore, there is a fundamental need to reliably detect inaccurate sensor values, which can arise, for example, if a sensor is defective, blocked, dirty, sooted, or missing. For example, it may not have been initially installed, removed during maintenance and not reinstalled, or deliberately removed with the intention of tampering. While it is possible to verify the plausibility of sensor values ​​recorded in a control device using computer models or additional sensors, additional tolerances and aging effects must be taken into account, so that threshold values ​​used to evaluate sensor behavior are defined quite roughly.It is therefore not always possible to set such threshold values ​​with sufficient sensitivity, which can regularly lead to problems if a sensor value changes only slightly over wide ranges, for example when checking the plausibility of an intake vacuum of an internal combustion engine, where only a very small pressure change of, for example, -15 mbar occurs between low load and full load.

[0003] DE 10 2018 108 115 B4 discloses a method for detecting and mitigating sensor or actuator degradations in an automotive system, comprising: collecting signal data from at least one device that outputs signal data related to operating parameters of a vehicle system; analyzing patterns of the signal data in comparison to patterns of signal data from a nominal operating device; and identifying when at least one of the patterns of signal data from the at least one device deviates from a threshold value, wherein the deviation indicates that the at least one device is operating in a degraded state; subsequently identifying how the deviation itself has changed over time, comprising continuously detecting the degradation of the patterns until a predetermined second threshold is reached, indicating a sensor or actuator failure;and selecting between the following steps: (a) generating correction data to change the operating parameters of the vehicle system so that the at least one of the patterns corresponds to the patterns of the signal data of the nominal operating device; or (b) if the correction data cannot change the patterns to correspond to the patterns of the signal data of the nominal operating device, identifying the at least one device as faulty.;

[0004] Further methods and systems for operating a power device and for diagnosing sensors are also disclosed in DE 10 2022 203 170 B3 and DE 10 2004 040 924 B4.

[0005] The invention is based on the object of providing a method for operating a power device, a control device for a power device, configured to carry out such a method, and a power device having at least one sensor and such a control device operatively connected to the at least one sensor, wherein the aforementioned disadvantages are at least reduced, preferably avoided.

[0006] The object is achieved by providing the present technical teaching, in particular the teaching of the independent claims as well as the preferred embodiments disclosed in the dependent claims and the description.

[0007] The object is achieved in particular by providing a method for operating a power device, wherein the power device is operated in a first predetermined operating range, wherein a first diagnostic value of a sensor is detected while the power device is operated in the first predetermined operating range, wherein the power device is operated in a second predetermined operating range different from the first predetermined operating range, wherein a second diagnostic value of the sensor is detected while the power device is operated in the second predetermined operating range, and wherein a sensor behavior of the sensor is evaluated - in particular automatically - based on a comparison between the first diagnostic value and the second diagnostic value.The evaluation of sensor behavior is thus advantageously based on a comparison of sensor values, namely the diagnostic values, in different operating ranges of the power device. Any tolerances, drifts, and / or aging effects are compensated for, since values ​​from the same sensor are always compared, particularly in a timely manner. This allows for a sensitive evaluation even of sensors with only small changes in the recorded sensor values; in particular, threshold values ​​used for the evaluation can be sensitively data-based. Furthermore, the method is easy to implement, and no complex and expensive additional sensors or complicated computational models are required to evaluate a specific sensor.Without wishing to be bound by theory, the method is based on the idea that a sensor, if correctly installed and functioning, will record different sensor values ​​in different operating ranges of a power device. A comparison of these sensor values ​​assigned to the different operating ranges can therefore provide a statement as to whether the sensor is correctly installed and functioning. For example, a sensor value recorded in a control device would be constant, or at least nearly constant within a noise range, if the associated sensor were not installed or blocked at all, because no real measured values ​​would be recorded and the noise of the sensor value in the control device does not depend on the current operating range of the power device.

[0008] Within the scope of the method proposed here, the power device does not need to be specifically placed into the predetermined operating ranges; rather, it is sufficient to record the diagnostic values ​​whenever the power device is operating in the correspondingly assigned operating ranges anyway, i.e., during regular operation. Thus, the method can easily be implemented during normal operation of the power device and is not limited to special test, maintenance, or test bench runs.

[0009] It is possible for associated diagnostic values ​​to be recorded in more than two predetermined operating ranges. Additional diagnostic values ​​recorded in additional operating ranges can be beneficial for verifying the plausibility or increasing the accuracy of the evaluation of sensor behavior.

[0010] However, one embodiment provides that only the first diagnostic value is recorded in the first operating range and the second diagnostic value is recorded in the second operating range. Therefore, in this embodiment, no further operating ranges are used to evaluate the sensor behavior.

[0011] According to a further development of the invention, the first operating range and the second operating range are selected such that the first diagnostic value and the second diagnostic value differ by more than a predetermined distance value when the sensor is functional. Advantageously, the sensor can be evaluated with high accuracy in this case, particularly when the predetermined distance value is greater than an expected noise signal.

[0012] In particular, the first operating range and the second operating range are matched to the sensor in such a way that the first diagnostic value and the second diagnostic value differ by more than the predetermined distance value when the sensor is functional. In this way, the specific characteristic and / or an area of ​​application of the respective sensor under consideration is advantageously taken into account. In this case, and in particular also when defining the predetermined distance value, it is advantageous to take into account how strongly the detected sensor value is expected to change depending on the operating range of the power device. The first operating range and the second operating range, and alternatively or additionally also the predetermined distance value, can therefore be selected differently depending on the specific sensor under consideration and / or its area of ​​application.

[0013] According to a further development of the invention, the operating ranges are load ranges. This represents a particularly advantageous embodiment of the method, since sensor values ​​can typically change significantly depending on the load of a power device.

[0014] In one embodiment, a lower load is assigned to the first predetermined load range than to the second predetermined load range. This advantageously ensures a particularly pronounced or significant difference in the recorded diagnostic values.

[0015] Alternatively or additionally, at least one load range, selected from the first predetermined load range and the second predetermined load range, is limited by a respective lower speed limit and a respective upper speed limit. The speed is a particularly suitable parameter for determining a load range of a power device, in particular an internal combustion engine. Preferably, both load ranges are limited by a respective lower speed limit and a respective upper speed limit. The speed limits can be configured as characteristic curves or curves.

[0016] Alternatively or additionally, at least one load range selected from the first predetermined load range and the second predetermined load range is limited by a respective lower torque limit and a respective upper torque limit. The torque is also a particularly suitable parameter for determining a load range of a power device, in particular an internal combustion engine. Preferably, both load ranges are limited by a respective lower torque limit and a respective upper torque limit. The torque limits can be configured as characteristic curves or curves.

[0017] In a preferred embodiment, the at least one load range is limited by a respective lower speed limit, a respective upper speed limit, a respective lower torque limit and a respective upper torque limit. It is possible for the at least one load range to be defined as a rectangle in a load diagram of the power device spanned on the one hand by the speed and on the other hand by the torque. Preferably, both load ranges are limited by a respective lower speed limit, a respective upper speed limit, a respective lower torque limit and a respective upper torque limit, wherein they are particularly preferably each defined as a rectangle in the load diagram of the power device spanned on the one hand by the speed and on the other hand by the torque. However, the load ranges do not have to be specified as rectangles.Rather, their torque and / or speed limits can also be specified as characteristic curves that deviate from the constant curve, i.e., the horizontal or vertical straight line in the load diagram, and in particular are curved at least in some areas, defining lower and upper load thresholds. The characteristic curves can have any desired curve shape. In one embodiment, the torque limits can be specified as characteristic curves that deviate from the constant curve, preferably curved at least in some areas, while the speed limits are configured as constants.

[0018] Alternatively or additionally, a finite speed difference is established between a first upper speed limit of the first predetermined load range and a second lower speed limit of the second predetermined load range. This can advantageously ensure that a clear, distinct, or significant difference results in the recorded diagnostic values.

[0019] Alternatively or additionally, a finite torque difference is established between a first upper torque limit of the first predetermined load range and a second lower torque limit of the second predetermined load range. This can also advantageously ensure that a clear, distinct, or significant difference results in the recorded diagnostic values.

[0020] In a preferred embodiment, there is a finite speed difference between the first upper speed limit of the first predetermined load range and the second lower speed limit of the second predetermined load range, and there is also a finite torque difference between the first upper torque limit of the first predetermined load range and the second lower torque limit of the second predetermined load range. If the load ranges are defined as rectangles in the load diagram spanned by the speed on the one hand and the torque on the other, they are offset and spaced from one another along the speed axis on the one hand and along the torque axis on the other.

[0021] According to a further development of the invention, a measured value from the sensor is recorded as at least one diagnostic value selected from the first diagnostic value and the second diagnostic value. This represents a particularly simple embodiment of the method.

[0022] Alternatively, an average value from a plurality of sensor measurements is recorded as the at least one diagnostic value. This represents a particularly precise and reliable embodiment of the method, which is less affected by any outliers than if only one measurement value were recorded as the diagnostic value.

[0023] According to a further development of the invention, the comparison between the first and second diagnostic values ​​is performed by forming a first difference of a diagnostic difference between the diagnostic values, wherein the first difference is compared with a predetermined minimum diagnostic difference. This advantageously represents a simple yet precise method for evaluating sensor behavior.

[0024] In one embodiment, the sensor behavior is assessed as "OK" if the first difference is greater than the predetermined minimum diagnostic difference. This advantageously results from the idea already described above that, with a correctly installed and functional sensor, a minimum change in the sensor value recorded in the control device can be expected when the operating range of the load device changes. The predetermined minimum diagnostic difference can be defined differently depending on the specific sensor under consideration and / or its area of ​​application. It can also be the same as or different from the previously described distance value. The category "OK" can also be defined the same as or differently from the category "functional."

[0025] Alternatively or additionally, the sensor behavior is assessed as "not OK" if the first difference is less than the predetermined minimum diagnostic difference. This is advantageously based on the complementary idea that something must be wrong with the sensor if a change in the operating range does not result in a corresponding change in the recorded sensor value. A "not OK" sensor behavior can mean that the sensor is defective, blocked, dirty, or sooted, or that the sensor is missing entirely.

[0026] According to a further development of the invention, it is provided that for at least one operating range selected from the first operating range and the second operating range, it is checked whether the power device is operated in the operating range for a predetermined operating range operating time, wherein the diagnostic value assigned to the operating range is only recorded if the power device is operated in the operating range for the predetermined operating range operating time. This advantageously ensures that a steady-state operating behavior of the power device and thus also of the sensor has been established before the sensor behavior is evaluated. Otherwise, overshoots or the like could possibly occur during transient operation, which would possibly impair the accuracy of the evaluation of the sensor behavior.

[0027] In one embodiment, a first predetermined operating range operating time is used for the first operating range, and a second predetermined operating range operating time is used for the second operating range. In one embodiment, it is possible for the first predetermined operating range operating time and the second predetermined operating range operating time to be the same; however, in another embodiment, the first predetermined operating range operating time can also be different from the second predetermined operating range operating time.

[0028] According to a further development of the invention, it is provided that in each of the operating ranges, an environmental parameter value influencing or characterizing the respective diagnostic value is recorded. This can advantageously help ensure that the observed sensor behavior is not significantly influenced by changing environmental conditions.

[0029] In one embodiment, the recorded ambient parameter values ​​are used to determine whether the evaluation of the sensor behavior could be disrupted by a change in the ambient parameter. For example, a change in the ambient pressure can lead to a change in the recorded sensor value of a pressure sensor, even when the operating range is kept constant, so that a comparison of the diagnostic values ​​measured in the different operating ranges is no longer meaningful. Such a change in the ambient pressure can occur, for example, when the altitude of the power device changes, for example, during an uphill or downhill journey.

[0030] In one embodiment, the sensor's behavior is only evaluated based on a comparison of the first and second diagnostic values ​​if it is determined from the recorded environmental parameter values ​​that the evaluation is not affected by the change in the environmental parameter. This, in particular, ensures that a meaningful and reliable statement about the sensor's behavior is made.

[0031] According to a further development of the invention, the sensor behavior of the sensor is only evaluated based on the comparison of the first and second diagnostic values ​​if a second difference of a parameter difference between the ambient parameter values ​​recorded in the operating ranges is smaller than a predetermined maximum parameter difference. This is advantageously based on the idea that no meaningful and reliable statement about the sensor behavior can be made if the second difference exceeds the maximum parameter difference and thus a significant change in the ambient conditions has occurred. The predetermined maximum parameter difference can be defined differently depending on the specific sensor under consideration and / or its area of ​​application.

[0032] According to a further development of the invention, the sensor is selected from a group consisting of a pressure sensor and a temperature sensor. The previously described advantages are particularly realized with these sensors. However, the method is by no means limited to these sensors.

[0033] The object is also achieved by providing a control device for a power device that is configured to carry out a method according to the invention or a method according to one or more of the previously described embodiments. In connection with the control device, the advantages that were previously described in connection with the method arise, in particular.

[0034] In one embodiment, the control device has at least one interface for operative connection with the at least one sensor.

[0035] Finally, the object is also achieved by providing a power device comprising at least one sensor and a control device according to the invention, or a control device according to one or more of the previously described embodiments, operatively connected to the at least one sensor, wherein the control device is configured to evaluate the sensor behavior of the at least one sensor. In connection with the power device, the advantages that have already been described previously in connection with the method or the control device are particularly advantageous.

[0036] In the context of the present technical teaching, a power device is generally understood to be a device configured to provide power, in particular electrical and / or mechanical power, or to convert or consume power. The power device can thus be designed as a power supply device or as a power conversion device. A power supply device is generally understood to be a device that provides power, in particular electrical and / or mechanical power, using electrical, mechanical, chemical, or electrochemical energy—or another form of energy.A power conversion device is generally understood to be a device that uses or consumes power, in particular electrical or mechanical power, to convert or store energy, for example to provide chemical energy in the form of certain substances such as hydrogen or methanol, or electrochemical energy, using electrical energy. In various embodiments, the power device can be an internal combustion engine, a combined internal combustion engine-generator device, i.e. a genset, a fuel cell, an energy storage device, in particular a battery, or an electrolyzer. However, the power device can also be a larger, complex system, for example comprising a plurality of the aforementioned devices, or in particular also a data center or a microgrid.The power device can also be a controllable or adjustable load on an electrical network.

[0037] In one embodiment, the power device has a plurality of sensors, wherein the control device is operatively connected to the sensors and configured to evaluate the respective sensor behavior of the sensors. It is possible for the control device to be configured to evaluate the sensor behavior of all sensors of the power device; however, it is also possible for the control device to be configured to only evaluate the sensor behavior of a selected minority of sensors of the power device, while the power device has further sensors whose sensor behavior is not evaluated by the control device. Nevertheless, these further sensors can also be operatively connected to the control device in order to transmit sensor values ​​to the control device and / or to be controlled by the control device.

[0038] The invention also includes a vehicle having a power device according to the invention or a power device according to one or more of the previously described embodiments. In connection with the vehicle, the advantages already described above in connection with the method, the control device, or the power device are realized in particular.

[0039] In one embodiment, the vehicle has the power device as a drive or part of a drive, in particular as a motor or as a device for providing drive power for a motor.

[0040] The vehicle is preferably selected from a group consisting of an excavator, a lorry or truck, a mining vehicle or construction vehicle, in particular a wheel loader or dump truck, a rail vehicle, a marine vehicle, for example a yacht, a ferry or a submarine, and a military vehicle, in particular an armoured vehicle, for example a battle tank, infantry fighting vehicle, armored reconnaissance vehicle, mine clearance vehicle or the like.

[0041] The invention is explained in more detail below with reference to the drawings, which show: Fig. 1 is a schematic representation of an embodiment of a power device; Fig. 2 a schematic representation of operating areas for a method for operating the power device, and Fig. 3 a representation of an embodiment of the method in the form of a flow chart.

[0042] Fig. 1 shows a schematic representation of an embodiment of a power device 1.

[0043] The power device 1 has at least one sensor 3 and a control device 5 operatively connected to the at least one sensor 3. The control device 5 is configured to evaluate the sensor behavior of the at least one sensor 3.

[0044] The power device 1 is preferably part of a vehicle 7, which is only indicated schematically. The vehicle 7 can have the power device as a drive or part of a drive, in particular as a motor or as a device for providing drive power for a motor. The vehicle 7 is preferably selected from a group consisting of an excavator, a lorry or truck, a mining vehicle or construction vehicle, in particular a wheel loader or dump truck, a rail vehicle, a marine vehicle, for example a yacht, a ferry or a submarine, and a military vehicle, in particular an armored vehicle, for example a battle tank, infantry fighting vehicle, armored reconnaissance vehicle, mine clearance vehicle or the like.

[0045] The sensor 3 is preferably selected from a group consisting of a pressure sensor and a temperature sensor.

[0046] The control device 5 is preferably configured to carry out an embodiment of a method for operating the power device 1 described below.

[0047] Fig. 2 shows a schematic representation of operating ranges for a method for operating the power device 1.

[0048] Identical and functionally identical elements are provided with the same reference symbols in all figures, so that reference is made to the preceding description in each case.

[0049] Within the scope of the method, the power device 1 is operated in a first predetermined operating range B1, wherein a first diagnostic value D1 - see Fig. 3 - of the sensor 3 is detected while the power device 1 is operated in the first predetermined operating range B1. The power device 1 is also operated in a second predetermined operating range B2 different from the first predetermined operating range B1, wherein a second diagnostic value D2 - see Fig. 3 - of the sensor 3 is detected while the power device 1 is operating in the second predetermined operating range B2. A sensor behavior of the sensor 3 is evaluated - in particular automatically - based on a comparison between the first diagnostic value D1 and the second diagnostic value D2.

[0050] In this case, the first operating range B1 and the second operating range B2 are preferably selected, in particular matched to the sensor 3, in such a way that the first diagnostic value D1 and the second diagnostic value D2 differ by more than a predetermined distance value when the sensor 3 is functional.

[0051] The operating ranges B1, B2 are load ranges in the exemplary embodiment shown here. A lower load is assigned to the first predetermined operating range B1 than to the second predetermined operating range B2. The operating ranges B1, B2 are defined, for example, as rectangles in a load diagram 9 of the power device 1, which is preferably designed as an internal combustion engine and spanned on the one hand by a rotational speed n and on the other hand by a torque M. As a further example, the operating ranges B1 and B2 could also assume other geometric shapes, which can be arbitrarily defined by specifying the lower and upper torque limits M1, u , M1, o , M2, u , M2 o The first predetermined operating range B1 is defined by a first lower speed limit n 1,u , a first upper speed limit n 1,o and also a first lower torque limit M 1,uand a first upper torque limit M 1,o Accordingly, the second predetermined operating range B2 is limited by a second lower speed limit n 2,u , a second upper speed limit n 2,o and also a second lower torque limit M 2,u and a second upper torque limit M 2,o limited.

[0052] Between the first upper speed limit n 1,o of the first predetermined operating range B1 and the second lower speed limit n 2,u of the second predetermined operating range B2 is a finite speed difference Δn = (n 2,u - n 1,o ) is given. In addition, between the first upper torque limit M 1,o of the first predetermined operating range B1 and the second lower torque limit M 2,u of the second predetermined operating range B2 a finite torque difference ΔM = (M 2,u - M 1,o ) given.

[0053] Fig. 3 shows a representation of an embodiment of the method for operating the power device 1 in the form of a flow chart.

[0054] The flowchart—and thus the method—is divided into an upper first part, designated I, and a lower second part, designated II. The first part I and the second part II of the method preferably run simultaneously and in parallel to one another, at least over large portions of the operation of the power device 1, and are linked to one another in the manner described in more detail below.

[0055] The method starts in a first step S1, in which at least one start condition is optionally checked. The at least one start condition can be selected in such a way that it contributes to avoiding excessive repetition of the evaluation process, which may be rather slow on a timescale of a typical changeover interval between operating ranges of the power device 1, which advantageously contributes to debouncing the evaluation. For example, a start condition can be defined as a predetermined period of time having elapsed since the last evaluation was performed.

[0056] If at least one start condition is not met, the first step S1 is repeated. If at least one start condition is met—in particular, if a plurality of start conditions or, where applicable, all start conditions are met cumulatively—the method continues in a second step S2.

[0057] In the second step S2, it is checked whether the power device 1 is currently operating in the first operating range B1 or in the second operating range B2. If the power device 1 is not currently operating in either of these operating ranges, the second step S2 is repeated. Otherwise, the method continues in a third step S3.

[0058] The third step S3 comprises a combination of sub-steps executed in parallel, a first sub-step S3.1 and a second sub-step S3.2. In the first sub-step S3.1, a diagnostic value Dx associated with the current operating range Bx - that is, the first operating range B1 or the second operating range B2 - is determined - that is, the first diagnostic value D1 or the second diagnostic value D2. In addition, an environmental parameter value Px associated with the current operating range Bx, influencing or characterizing the respective diagnostic value Dx, for example, an ambient pressure, is determined. In the second sub-step S3.2, a time t(Bx) is monitored for which the power device 1 is in the current operating range Bx. In this case, a check is carried out to determine whether the power device 1 is in the current operating range Bx for a predetermined operating range operating period t W,Bxis operated in the current operating area Bx.

[0059] If this is not the case, i.e. the operation of the power device 1 in the current operating range Bx ends before the expiry of the assigned predetermined operating range operating time t W,Bx , the method branches back to the second step S2, and the diagnostic values ​​Dx and environmental parameter values ​​Px determined up to that point are discarded, thus not recorded in the narrower sense. Otherwise, the determined diagnostic values ​​Dx and environmental parameter values ​​Px are stored and thus recorded in the narrower sense for the subsequent method; the method then continues in a fourth step S4.

[0060] As diagnostic value Dx, a measured value of the sensor 3 or a temporal average of a plurality of temporally successive measured values ​​of the sensor 3 over the predetermined operating range operating time t W,Bx be recorded.

[0061] In the fourth step S4, a check is made as to whether a diagnostic value D1, D2 is present for each of the two operating ranges B1, B2. If the method is executed repeatedly, a check is made in the fourth step S4 as to whether an updated diagnostic value D1, D2 is present for at least one of the two operating ranges B1, B2. If the test result in the fourth step S4 is negative, the system branches back to the second step S2; if, however, the test result in the fourth step S4 is positive, the diagnostic values ​​D1, D2 or at least the updated diagnostic value D1, D2 are transferred to a fifth step S5 in the second part II of the method, and at the same time the system branches back to the first step S1.

[0062] In the fifth step S5, a check is carried out to determine whether any values ​​are initially present or, in the case of a recurrence, whether at least one new or updated value is present for the diagnostic values ​​D1, D2. In one embodiment, it is possible for the check result in the fifth step S5 to be positive only if new or updated values ​​are present for both diagnostic values ​​D1, D2; in another embodiment, it is possible for the check result in the fifth step S5 - in the case of a recurrence - to be positive if an updated value is present for one of the two diagnostic values ​​D1, D2. If the check result is negative, the fifth step S5 is repeated; if the check result is positive, the method continues in a sixth step S6.

[0063] In the sixth step S6, the recorded environmental parameter values ​​P1, P2 are used to check whether the evaluation of the sensor behavior could be disturbed by a change in the environmental parameter. For this purpose, a parameter difference (P2 - P1) between the environmental parameter values ​​P1, P2 recorded in the operating ranges B1, B2, referred to as the second difference, is calculated based on the recorded environmental parameter values ​​P1, P2. A check is carried out to determine whether this second difference is smaller than a predetermined maximum parameter difference P. max If this is not the case, the process branches back to the fifth step S5, and the sensor behavior is not evaluated based on the currently available diagnostic values ​​D1, D2. If, however, the test result in the sixth step S6 is positive, the process continues in a seventh step S7.

[0064] In the seventh step S7, the comparison between the first diagnostic value D1 and the second diagnostic value D2 is carried out by forming the already mentioned first difference amount of a diagnostic difference (D2 - D1) between the diagnostic values ​​D1, D2, wherein it is checked whether the first difference amount is greater than a predetermined minimum diagnostic difference D min .

[0065] If this is the case, the sensor behavior is assessed as "OK" in an eighth step S8. If, however, the test result in the seventh step S7 is negative, the sensor behavior is assessed as "not OK" in a ninth step S9.

[0066] The method then provisionally ends in a tenth step S10. The tenth step S10 can optionally include further measures, in particular for debouncing the method, for example, low-pass filtering. Furthermore, the tenth step S10—as schematically shown here—can have a feedback effect on the first step S1 of the first part I and optionally influence the at least one start condition, for example, by providing feedback of a system time of the performed evaluation or by influencing certain parameters for debouncing. At the same time, however, the second part II of the method also continues in the fifth step S5.

[0067] Overall, the method is preferably carried out continuously during the operation of the power device 1. Alternatively, however, it is also possible for the method to be carried out only temporarily, for example at predetermined time intervals, in particular measured in operating hours, at predetermined operating times, or depending on the occasion.

Claims

[1] Method for operating a power device (1), wherein - the power device (1) is operated in a first predetermined operating range (B1), wherein - a first diagnostic value (D1) of a sensor (3) is detected while the power device (1) is operated in the first predetermined operating range (B1), wherein - the power device (1) is operated in a second predetermined operating range (B2) different from the first predetermined operating range (B1), wherein - a second diagnostic value (D2) of the sensor (3) is detected while the power device (1) is operated in the second predetermined operating range (B2), and wherein - a sensor behavior of the sensor (3) is evaluated based on a comparison between the first and second diagnostic values ​​(D1, D2). [2] Method according to claim 1, wherein the first operating range (B1) and the second operating range (B2) are selected and optionally matched to the sensor (3) such that the first diagnostic value (D1) and the second diagnostic value (D2) differ by more than a predetermined distance value when the sensor (3) is functional. [3] Method according to one of the preceding claims, wherein the operating ranges (B1, B2) are load ranges, wherein optionally the first predetermined load range is assigned a lower load than the second predetermined load range, wherein alternatively or additionally - at least one load range selected from the first predetermined load range and the second predetermined load range is limited by a respective lower speed limit and a respective upper speed limit, and / or - at least one load range selected from the first predetermined load range and the second predetermined load range is limited by a respective lower torque limit and a respective upper torque limit, and / or - between a first upper speed limit (n 1,o ) of the first predetermined load range and a second lower speed limit (n 2,u ) of the second predetermined load range, a finite speed difference (Δn) is given, and / or - between a first upper torque limit (M 1,o ) of the first predetermined load range and a second lower torque limit (M 2,u ) of the second predetermined load range, a finite torque difference (ΔM) is given. [4] Method according to one of the preceding claims, wherein as at least one diagnostic value (D1, D2) selected from the first diagnostic value (D1) and the second diagnostic value (D2), - a measured value of the sensor (3), or - an average value is recorded from a plurality of measured values ​​of the sensor (3). [5] Method according to one of the preceding claims, wherein the comparison between the first and the second diagnostic value (D1, D2) is carried out by forming a first difference amount of a diagnostic difference between the diagnostic values ​​(D1, D2), wherein the first difference amount is compared with a predetermined minimum diagnostic difference (D min ) is compared, optionally - the sensor behavior is assessed as “OK” if the first difference is greater than the predetermined minimum diagnostic difference (D min ), and / or - the sensor behavior is assessed as “not OK” if the first difference is smaller than the predetermined minimum diagnostic difference (D min ). [6] Method according to one of the preceding claims, wherein for at least one operating range (B1, B2) selected from the first operating range (B1) and the second operating range (B2), it is checked whether the power device (1) is in operation for a predetermined operating range operating time (t W,Bx ) is operated in the operating range (B1, B2), wherein the diagnostic value (D1, D2) assigned to the operating range (B1, B2) is only detected if the power device (1) is operated for the predetermined operating range operating time (t W,Bx ) in the operating area (B1, B2). [7] Method according to one of the preceding claims, wherein in each of the operating ranges (B1, B2) an environmental parameter value (P1, P2) of an environmental parameter is detected which influences or characterizes the respective diagnostic value (D1, D2), wherein optionally a check is carried out on the basis of the detected environmental parameter values ​​(P1, P2) as to whether the evaluation of the sensor behavior can be disturbed by a change in the environmental parameter, wherein further optionally the sensor behavior of the sensor (3) is only evaluated on the basis of the comparison of the first and second diagnostic values ​​(D1, D2) if it is determined on the basis of the detected environmental parameter values ​​(P1, P2) that the evaluation is not disturbed by the change in the environmental parameter. [8] Method according to claim 7, wherein the sensor behavior of the sensor (3) is only evaluated based on the comparison of the first and second diagnostic values ​​(D1, D2) if a second difference amount of a parameter difference between the environmental parameter values ​​(P1, P2) respectively detected in the operating ranges (B1, B2) is smaller than a predetermined maximum parameter difference (P max ). [9] Method according to one of the preceding claims, wherein the sensor (3) is selected from a group consisting of a pressure sensor and a temperature sensor. [10] Control device (5) for a power device (1), arranged to carry out a method according to one of claims 1 to 9. [11] Power device (1) with at least one sensor (3) and a control device (5) operatively connected to the at least one sensor (3) according to claim 10, wherein the control device (5) is configured to evaluate the sensor behavior of the at least one sensor (3).

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