Method and device for wear analysis of a component of a motor vehicle

Abstract

The invention relates to a method for the wear analysis of at least one component of a motor vehicle. Sensor data are captured by at least one sensor, the sensor data being captured in order to provide at least one basic function of the motor vehicle and / or of a drive train of the motor vehicle. Data which are dependant on an instantaneous state of the at least one component are calculated using a model, the model receiving the captured sensor data as an input variable. Information regarding instantaneous wear of the at least one component is determined using the calculated data.

Description

[0001] Description

[0002] title

[0003] Method and device for wear analysis of a component of a motor vehicle

[0004] The present invention relates to a method and a corresponding device for wear analysis of a component of a motor vehicle.

[0005] State of the art

[0006] The components of a drive train are designed based on stored load profiles. A load profile can be understood as the statistical load-dependent distribution of one or more physical variables, such as the temporal dependence of temperature fluctuations or the dependence of torque on speed.

[0007] The load profiles are usually based on assumptions or are transferred from field data from combustion vehicles and adjusted accordingly. However, there is often insufficient field data from powertrains to validate or compare load profiles with the field data. Furthermore, the status of a component or the status of the entire powertrain cannot be verified in the field; only statistical failure probabilities can be considered.

[0008] One way to compare the stored load profiles with field data and, if necessary, adjust the load profiles during operation is a wear analysis. This allows the vehicle manufacturer, a supplier, or even the end user (such as a fleet operator or a private user) to be informed at regular intervals about the current state of wear or aging (or "state of health") of the respective powertrain.

[0009] EP 1 623284 B1 discloses a method for optimizing vehicles, in which the vehicle is simulated. AT 518850 B1 relates to another method for simulation-based analysis or optimization of a motor vehicle. DE 10 2019 202 980 A1 relates to a system for determining analysis data for the further development of a mobility system. DE 10 2019 219436 A1 relates to a method for detecting a load-related condition.

[0010] Disclosure of the invention

[0011] The invention provides a method and a device for wear analysis of at least one component of a motor vehicle with the features of the independent patent claims.

[0012] Preferred embodiments are the subject of the respective subclaims.

[0013] According to a first aspect, the invention accordingly relates to a method for wear analysis of at least one component of a motor vehicle. Sensor data is acquired by at least one sensor, wherein the sensor data is acquired to provide at least one basic function of the motor vehicle and / or the drive train. Data dependent on a current state of the at least one component is calculated using a model, wherein the model receives the acquired sensor data as an input variable. Information regarding current wear of the at least one component is determined using the calculated data.

[0014] According to a second aspect, the invention relates to the wear analysis of at least one component of a motor vehicle. The device comprises an interface which is designed to receive sensor data from at least one sensor of the motor vehicle, wherein the at least one sensor acquires the sensor data to provide at least one basic function of the motor vehicle and / or the drive train. The device further comprises a computing device which is designed to calculate data which depend on a current state of the at least one component using a model, wherein the model receives the acquired sensor data as an input variable, and to determine information regarding current wear of the at least one component using the calculated data.

[0015] Advantages of the invention

[0016] According to the invention, to calculate the data that depends on the current state of the at least one component, sensor data is used that is acquired by sensors that are already required to provide basic functions of the motor vehicle and / or the powertrain. Such sensors are therefore already standard sensors in the motor vehicle. In particular, these sensors are not additional dedicated sensors specifically designed for wear analysis.

[0017] The invention can thus provide a very accurate wear analysis, i.e., a determination of information regarding current wear, in a quick and cost-effective manner using software models or algorithms without the need for additional sensors. This eliminates the need for additional sensors, or allows existing sensors to be eliminated.

[0018] In contrast to a purely load profile-based wear analysis, by taking sensor data into account, the currently prevailing damage of the respective component can not only be calculated but also actually recorded. This makes it possible to measure not only the theoretical condition, but also the actual condition of the respective component of the vehicle. This actual condition of the component of the vehicle can then be compared with the stored damage (permitted over the service life), which may result from the respective load profile. Furthermore, it can be recorded if a component exhibits unusual behavior, such as high vibrations, pressures, unusual current patterns, or similar. This allows the remaining wear to be predicted with great accuracy. Furthermore, it is possible to replace components in the workshop before they are destroyed or seriously damaged.This helps avoid unnecessary major repairs.

[0019] By knowing the remaining wear and tear, the vehicle's remaining, precisely defined, minimum service life can be determined when reselling it. This allows the vehicle's residual value, or resale value, to be determined much more accurately.

[0020] Furthermore, a learning process optionally implemented in the wear analysis function allows the component to be designed much more precisely for the actual stress or damage over its lifetime. This can reduce the overall weight of the vehicle, lower material costs, and reduce the costs for component testing as well as for testing the entire powertrain. Furthermore, a lifetime guarantee or warranty can be increased if necessary.

[0021] Furthermore, sensors in the electric drive train can be eliminated because the load on the respective components is known, which in turn saves costs and weight.

[0022] A sensor that collects sensor data to provide at least one basic function of the motor vehicle and / or the drive train can be understood as standard sensors, such as those for detecting speed and torque or the like. A "basic function" can be understood as providing a desired drive torque, i.e., accelerating or decelerating the vehicle according to the driver's command. The basic function can also include monitoring a coolant circuit or the like. A basic function is therefore required for standard operation of the motor vehicle and / or the drive train.

[0023] According to a further embodiment of the method for wear analysis of at least one component of the motor vehicle, only the recorded sensor data is considered for calculating the data. In particular, the model does not receive any sensor data from additional dedicated sensors that might be specifically intended for wear analysis. Such additional sensors can thus be eliminated. The method is "sensorless" in that no special sensors can be provided; instead, only the sensor data from the sensors already installed as standard in the motor vehicle are evaluated to perform the wear analysis.

[0024] According to a further embodiment of the method for wear analysis of at least one component of the motor vehicle, the recorded sensor data comprise at least one of a torque of an electric machine of the motor vehicle, a speed of the electric machine, a direct current applied to an electric drive train (in particular to power electronics of the electric drive train), a direct voltage applied to the electric drive train, an alternating voltage applied to the electric machine, a temperature of power electronics and / or electric machine, a coolant volume flow and a coolant temperature. The sensor data can also occur multiple times in each case, for example, multiple temperatures can be measured. The sensor data can thus be recorded in particular by sensors installed in the drive train.In particular, the measured torques, speeds, or currents can be taken into account. In one embodiment, additional sensor data for wear analysis is not available.

[0025] According to a further embodiment of the method for wear analysis of at least one component of the motor vehicle, the calculated data comprise at least one temperature of the at least one component. The data can further comprise at least one of a hotspot temperature of a stator, a temperature in a film capacitor, a temperature of a power module, a temperature in the transmission, a temperature of a transmission oil, a temperature of a cooling medium at various points within the drivetrain, a direct current, an alternating current, a torque or a rotational speed at the output of an electric axle, a torque or a rotational speed at the transition from the electric machine to a transmission or between individual transmission stages, a temperature at a coupling or decoupling system, a temperature of a park lock system or other components of the drivetrain.Again, the data can occur multiple times, for example, hotspot temperatures can include several stators.

[0026] According to a further embodiment of the method for wear analysis of at least one component of the motor vehicle, the model for calculating the data models the at least one component. This can be, for example, a finite element model.

[0027] According to a further embodiment of the method for wear analysis of at least one component of the motor vehicle, a remaining wear of the at least one component is predicted using a comparison of the determined information regarding the current wear of the at least one component with predetermined information regarding a maximum permissible wear of the at least one component.

[0028] According to a further embodiment of the method for wear analysis of at least one component of the motor vehicle, the information relating to a current wear of the at least one component comprises a ratio of a variable describing the current wear to a variable describing the maximum permissible wear.

[0029] According to a further embodiment of the method for wear analysis of at least one component of the motor vehicle, the predetermined information regarding a maximum permissible wear of the at least one component comprises a load profile of the at least one component. Thus, stored load profiles can be compared with field data, i.e., validated, and the load profiles can be adjusted during operation if necessary. Based on the load profile, the maximum permissible wear of the component over the service life can be determined. With the help of damage models (damage formulas with corresponding coefficients), the current damage can be calculated, compared with the maximum permissible damage over the service life, and residual damage or predicted remaining service life can be determined.

[0030] According to a further embodiment of the method for wear analysis of at least one component of the motor vehicle, a remaining operating time of the at least one component and / or a remaining range of the motor vehicle is determined based on the predicted remaining wear of the at least one component. The remaining operating time and / or remaining range can be determined by extrapolating the wear of the component, assuming that the driver continues driving with a previously determined driving style. Alternatively, a driving profile can be stored to represent a standard driver.

[0031] According to a further embodiment of the method for wear analysis of at least one component of the motor vehicle, a wear state (state of health) is determined based on the predicted remaining wear of the component. The wear state can, for example, indicate the current wear as a percentage of the wear permissible over the entire service life (maximum damage).

[0032] According to a further embodiment of the method for wear analysis of at least one component of the motor vehicle, unusual wear behavior of the component is registered if the sensor data and / or the information regarding the current wear of the component exhibit unusual behavior. This can be understood, for example, as meaning that the evaluation of the sensor data and / or the information regarding the current wear of the component lies outside a predetermined range, i.e., falls below or exceeds predetermined threshold values.

[0033] According to a further embodiment of the method for wear analysis of at least one component of the motor vehicle, a warning signal and / or a recommended course of action is issued to a user based on the predicted remaining wear of the at least one component. The user can be, for example, a driver of the vehicle, a manufacturer, a fleet operator, or the like. The warning signal can be issued, for example, if unusual wear behavior of the component is detected. The warning signal can, for example, indicate that the maximum permissible wear will soon be reached or that there is a discrepancy in the component detected based on the sensor data.

[0034] According to a further embodiment of the method for wear analysis of at least one component of the motor vehicle, the remaining wear of the component or the wear state of the component is communicated to the vehicle manufacturer, a supplier (in particular the manufacturer of the component) and / or the end user (fleet operator or private user) at regular intervals or continuously.

[0035] According to a further embodiment of the method for wear analysis of at least one component of the motor vehicle, the component is an electric drive or a part of an electric drive.

[0036] According to a further embodiment of the method for wear analysis of at least one component of the motor vehicle, the prediction of the remaining wear of the component is carried out by means of an evaluation device of the motor vehicle.

[0037] According to a further embodiment of the method for wear analysis of at least one component of the motor vehicle, the prediction of the remaining wear of the component is carried out by means of an evaluation device located outside the motor vehicle.

[0038] According to a further embodiment of the method for wear analysis of at least one component of the motor vehicle, the component can be a shaft seal, a bearing, a bearing grease, a transmission oil, a gear, a differential, a side gear, a spur gear, a pinion, a plug-in connection, a parking lock system, a gearbox, a gearbox housing, a shaft, a seal, an output shaft, an input shaft, a coupling or decoupling system (disconnect unit), a retaining ring, welded components, or screws. Furthermore, it can be an electric motor or components thereof (such as a rotor, a stator, insulation or a bearing, a bearing grease, or a retaining ring).Furthermore, it can be an inverter or components thereof (e.g., power modules including a B6 bridge, B12 bridge, or Bx bridge, a discharge circuit, a DC capacitor, an EMC filter, a film capacitor, or the like). Furthermore, it can be a system or components thereof (e.g., a system housing, damping elements or seals, such as liquid seals or intermediate seals, radial shaft seals, components for voltage grounding, screws, cables, or liquids such as oil, water, or water-glycol mixtures).

[0039] Short description of the drawings

[0040] They show:

[0041] Figure 1 is a schematic block diagram of a device for wear analysis of a component of a motor vehicle; and

[0042] Figure 2 shows a flow chart of a method for wear analysis of a component of a motor vehicle.

[0043] The numbering of procedural steps is for clarity and generally does not imply a specific chronological order. In particular, several procedural steps can be performed simultaneously.

[0044] Description of the embodiments

[0045] Figure 1 shows a schematic block diagram of a device 1 for wear analysis of a component of a motor vehicle. The motor vehicle can be, in particular, an electric vehicle or a hybrid vehicle. The device 1 can be arranged in the motor vehicle or used outside the motor vehicle (e.g., as an external analysis system).

[0046] The device 1 comprises an interface 11 which is coupled to at least one sensor 2, for example via a CAN bus. The at least one sensor 2 is a standard sensor which is thus already present in the motor vehicle and does not have to be provided specifically for the wear analysis. The sensor data recorded by the at least one sensor 2 comprise, for example, a torque of an electric machine of the motor vehicle, a speed of the electric machine, a direct current applied to the electric machine, a direct voltage applied to the electric machine, an alternating voltage applied to the electric machine, a temperature of an electric drive train of the electric machine, a coolant volume flow or a coolant temperature.

[0047] The device 1 further comprises a storage device 12 with at least one non-volatile data memory for storing the sensor data received from the at least one sensor 2. Pre-provided information regarding a maximum permissible wear of the component is also stored in the storage device 12. This can be at least one load profile of the component.

[0048] The device 1 further comprises a computing device 13, such as a microprocessor, an integrated circuit, or the like. The computing device 13 calculates data that depend on a current state of the at least one component or that corrects this state (ie, in particular, can depend on a current wear state of the at least one component) using the acquired sensor data.

[0049] The computing device 13 determines information regarding the current wear of the at least one component using the calculated data. The computing device 13 can be arranged in the motor vehicle and / or in the device 1 or outside the motor vehicle and / or outside the device 1. Furthermore, the computing device 13 can determine the remaining wear of the component by comparing the determined information regarding the current wear of the component with predetermined information regarding a maximum permissible wear of the component.

[0050] The wear analysis can be carried out (especially for the load profile-based analysis) for example for one of the components listed in Table 1 with the corresponding exemplary damage mechanism.

[0051]

[0052] Table 1 Figure 2 shows a flowchart of a method for wear analysis of a component of a motor vehicle, such as a component of an electric drive. The method can be carried out using the device 1 described above. Conversely, the device 1 described above can be configured to carry out all or some of the method steps described below. In particular, all calculation steps can be carried out by the computing device 13.

[0053] In a first method step S1, a vehicle simulation is performed, taking into account vehicle data, data relating to the powertrain, and / or a driver profile determined from past measurement data. In particular, a frequency distribution of torque, speed, and / or voltage can be determined.

[0054] In a second process step S2, the variables determined in the first process step S1 (e.g., temperatures over frequency) can be used as input variables for a simulation model to simulate parameters required for calculating the maximum permissible wear of the component. The simulation model can include a thermal simulation of the component, for example, to determine a maximum temperature (hot spot temperature) of the component.

[0055] In a third method step S3, a wear calculation is performed to determine the maximum permissible wear of the component. The maximum permissible wear of the component can be stored in the storage device 12.

[0056] In a fourth method step S4, measurements are performed during operation of the motor vehicle using at least one standard sensor 2 to acquire sensor data. Sensor 2 acquires, for example, a torque, a rotational speed, and / or a current of a drive train.

[0057] In a fifth method step S5, data depending on a current state of the at least one component is calculated using a model, with the input parameters or variables of the model comprising the acquired sensor data. For example, a hottest temperature occurring at the stator can be determined using a thermal model.

[0058] The model can, for example, include one or more temperature models for at least one rotor, at least one stator, at least one gearbox, at least one oil, at least one AC busbar, at least one DC busbar, at least one power module, at least one DC link capacitor, at least one electromagnetic compatibility (EMC) filter, and at least one coolant failure diagnostic. The respective component is thus described and simulated entirely or partially by the model, and a corresponding temperature value is calculated depending on the input parameters.

[0059] The model may further include, for example, a torque accuracy model, a speed accuracy model, a voltage ripple model, a gearbox protection function, an AC current and voltage determination model from a given DC current and DC voltage, or a motor current signature analysis for a bearing, a rotor, a stator, a gearbox gear, or oil.

[0060] The sensor data can be compared with target values ​​to detect any discrepancies. These discrepancies can be incorporated into the calculation of the current wear of at least one component.

[0061] Furthermore, in the fifth method step S5, it may be provided to compare the sensor variables with a target value in order to register possible discrepancies.

[0062] In a sixth method step S6, information regarding the current wear of the at least one component is determined. For example, the number of occurrences and / or duration of this temperature can be determined for given temperatures of the component.

[0063] In a seventh process step S7, the information regarding the current wear of the component is compared with the determined information regarding the maximum permissible wear of the component. For example, histograms of temperature fluctuations can be compared with each other to determine to what extent the maximum permissible wear has already been reached. The remaining wear is then predicted and output. This can be a percentage that indicates the extent of the remaining residual wear. As an alternative to the temperature distribution (e.g. maximum temperature fluctuations over frequency), a damage distribution (damage over time) or total damage can also be calculated, for example from temperature fluctuations and / or temperature changes. Alternatively, this damage distribution or total damage is then compared with the maximum damage distribution or total damage permitted over the service life.

[0064] In an eighth method step S8, it can be determined whether the predicted remaining wear exceeds a specified threshold. If this is the case, a warning signal and / or a recommended course of action can be issued in a method step S9.

[0065] Predicting the remaining wear of the component can be performed in an evaluation device on the vehicle or in an external evaluation device located outside the vehicle. For example, the field data in the drivetrain can simply be recorded and collected. In a workshop, the field data is then transmitted via a diagnostic interface and can thus be processed with high computing power (outside the drivetrain).

[0066] Furthermore, it may be intended to draw conclusions based on these results, e.g. to determine a remaining service life or remaining mileage, or to provide warnings and / or recommendations for action in the event of discrepancies to the end customer, OEM, fleet operator and / or powertrain manufacturer or sub-supplier.

[0067] Furthermore, it can be provided that the field data in the drivetrain is simply recorded and collected and transmitted to the customer via a CAN interface, for example, to a cloud provided by the customer or the supplier or drive manufacturer. The field data can thus be processed with high computing power (outside the drivetrain).

[0068] Furthermore, it can be provided that the sensor data is recorded and processed in the drivetrain, i.e., that the current wear is calculated from the sensor data, which is then compared with a stored, maximum permissible wear. In the workshop, the information regarding the current wear or all data is transmitted via a diagnostic interface and can thus be further processed with high computing power (outside the drivetrain) or used for learning processes and statistics. This allows the stored load profiles and the resulting maximum permissible wear of the component to be adjusted at regular intervals.

[0069] Furthermore, it can be provided that the sensor data is recorded and processed in the drivetrain, i.e., that the current wear is calculated from the sensor data, which is then compared with a stored, maximum permissible wear. This damage or all data is transmitted to a user or a cloud via an interface, such as a CAN connection, and can thus be further processed with high computing power (outside the drivetrain) or used for learning processes and statistics. The stored load profiles can also be adjusted.

Claims

Claims 1 . A method for wear analysis of at least one component of a motor vehicle, comprising the steps: Acquiring (S4) sensor data by at least one sensor (2), wherein the sensor data are acquired to provide at least one basic function of the motor vehicle and / or a drive train of the motor vehicle; Calculating (S5) data which depend on a current state of the at least one component using a model, wherein the model receives the acquired sensor data as input; and Determining (S6) information regarding a current wear of the at least one component using the calculated data.

2. The method according to claim 1, wherein the acquired sensor data comprise at least one of a torque of an electric machine of the motor vehicle, a speed of the electric machine, a direct current applied to an electric drive train of the motor vehicle, a direct voltage applied to the electric drive train, an alternating voltage applied to the electric machine, a temperature at an electric drive train of the electric machine, a coolant volume flow and a coolant temperature.

3. The method of claim 1 or 2, wherein the calculated data includes at least one temperature of the at least one electrical component.

4. The method according to any one of the preceding claims, wherein the model for calculating the data models the at least one component. Method according to one of the preceding claims, further comprising the step: Predicting a remaining wear of the at least one component using a comparison of the determined information regarding the current wear of the at least one component with predetermined information regarding a maximum permissible wear of the at least one component. Method according to claim 5, wherein the predetermined information regarding a maximum permissible wear of the at least one component comprises a load profile of the at least one component. Method according to claim 5 or 6, wherein a remaining operating time of the at least one component and / or a remaining range of the motor vehicle is determined based on the predicted remaining wear of the at least one component. Method according to one of claims 5 to 7, wherein a warning signal and / or a recommended action is output to a user based on the predicted remaining wear of the at least one component.Method according to one of claims 5 to 8, wherein the prediction of the remaining wear of the at least one component is carried out by means of an evaluation device (1) of the motor vehicle. Device (1) for wear analysis of at least one component of a motor vehicle; comprising: an interface (11) which is designed to receive sensor data from at least one sensor (2) of the motor vehicle, wherein the at least one sensor (2) acquires the sensor data for providing at least one basic function of the motor vehicle and / or a drive train of the motor vehicle; and. a computing device (13) which is designed to calculate data which depend on a current state of the at least one component, using a model, wherein the model receives the detected sensor data as an input variable, and wherein the The computing device (13) is further designed to determine information relating to a current wear of the at least one component using the calculated data.

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