System and method for recording and evaluating a measured quantity

Abstract

System for acquiring and evaluating a measured quantity of at least one component of a vehicle, comprising at least one sensor (20) for acquiring a measured quantity of at least one component of the vehicle and for outputting an output quantity (22), and at least one evaluation unit (30) for evaluating the output quantity (22) and for generating a warning signal (32) depending on the evaluation of the output quantity (22) based on at least one defined warning criterion, wherein the measured quantity is a temperature, wherein the component of the vehicle is a wheel bearing, wherein the evaluation unit (30) is configured to generate the warning signal (32) when a predetermined, characteristic measured quantity profile is detected and / or when a predetermined deviation from a calculated measured quantity profile is exceeded, wherein several sensors (20) are provided, wherein a central warning unit (40) is present, which is configuredto issue warning messages (42) relating to the sensors (20), wherein at least one sensor (20) of the system is mounted on an axle head.

Description

The invention relates to a system and a method for acquiring and evaluating a measured variable of at least one component of a vehicle. In particular, the invention relates to a system and a method for acquiring and evaluating the temperature of at least one wheel bearing of a vehicle. The temperature development of a wheel bearing is a key indicator of its functional condition. A wheel bearing failure is often preceded by a temperature increase. Regularly monitoring the wheel bearing temperature is therefore a suitable method for checking its functionality and thus its operational reliability. For monitoring wheel bearing temperature, melting point indicators are known in the prior art. These indicators are designed so that when a defined temperature is exceeded, a component melts, changing the indicator's color. For example, a previously white surface might turn black when the component melts. This allows the system to determine whether a specific temperature has been exceeded at the measuring point. US 2013 / 0038436 A1 discloses a trailer equipped with multiple sensors for determining operating parameters. A computer is connected to the sensors. A visual or audible alarm is transmitted to the driver when safety-relevant information is received, such as low tire pressure or elevated brake or wheel bearing temperature. WO 9806078 A1 describes the acquisition of operating parameters such as tire pressure, wheel temperature, and vibration by sensors mounted on wheel modules. The vehicle owner or operator is notified if inefficient or unsafe operating conditions occur. Further sensor devices on vehicles for determining operating parameters are known from US 2009 / 0033510 A1, US 2014 / 0309860 A1, US 7 271 733 B2, US 2013 / 0234847 A1, US 2009 / 0284362 A1, DE 100 04 464 A1, DE 102 42 199 A1, US 2002 / 0167401 A1, US 2012 / 0032793 A1, US 2003 / 0074961 A1 and DE 10 2012 210 015 A1. The invention is based on the objective of providing a system and a method which ensure or enable a particularly reliable detection of a malfunction of a component of a vehicle, in particular a wheel bearing. The problem is solved according to the invention by a system having the features of claim 1 and a method having the features of claim 10. Preferred embodiments of the invention are specified in the dependent claims. The system according to the invention for detecting and evaluating a measured quantity, in particular a temperature of at least one component of a vehicle, in particular a wheel bearing, comprises the following components: at least one sensor for detecting a measured quantity, in particular a temperature, of at least one component of the vehicle, in particular a wheel bearing of the vehicle, and for outputting an output quantity, and at least one evaluation device for evaluating the output quantity and for generating (triggering) a warning signal depending on the evaluation of the output quantity based on at least one defined warning criterion. The inventive method for acquiring and evaluating a measured quantity, in particular a temperature, of at least one component, in particular a wheel bearing, of a vehicle, comprises the following steps: Acquiring a measured quantity, in particular a temperature, of at least one component, in particular a wheel bearing, of the vehicle and outputting an output quantity; evaluating the output quantity and generating a warning signal depending on the evaluation of the output quantity based on at least one defined warning criterion. The method according to the invention can be carried out, in particular, with a system according to the invention. The system according to the invention is particularly designed and suitable for carrying out the method according to the invention. A fundamental concept of the invention is to not only acquire the measured value but also to evaluate it and, based on this evaluation, issue a warning message when at least one predefined warning criterion is met. The measured value preferably relates to temperature, but other parameters, such as tire pressure, are also possible. Therefore, one aspect of the invention is to monitor the functionality of a wheel bearing by not only acquiring the temperature but also evaluating it. Based on this evaluation, a warning message is automatically issued when at least one predefined, and preferably adjustable or modifiable, warning criterion is met. Consequently, it is not necessary for the driver to manually read the temperature measuring device regularly.Rather, the evaluation unit automatically signals a warning situation to the driver or, if applicable, another person. The operational safety of the vehicle is increased by the automatic detection and signaling of a warning situation. In the context of the present invention, evaluation refers in particular to a single or multiple comparison of the measured value (especially temperature) with a reference value and / or a comparison of a time-dependent measured value profile with a time-dependent reference value profile. In principle, it is also conceivable to compare a spatial temperature distribution with a reference value by evaluating the output values ​​of several temperature sensors. The reference value or reference value profile can preferably be set or changed by an operator, particularly electronically, or automatically calculated by the system based on predefined input values. Furthermore, it is preferred that the evaluation is based on at least two comparisons (i.e., at least two comparisons are performed), for example, two successive comparisons of individual measured values ​​with one or more reference values.In this way, a first measured temperature value can be compared with a reference value, a second temperature value can subsequently be compared with a reference value, and based on these or possibly further comparisons, a yes / no decision can automatically be made about triggering or not triggering a warning message. In a preferred embodiment of the invention, the evaluation unit is configured to perform a comparison of at least one value of the output variable (measured value) with a comparison or reference value. The evaluation unit receives an output variable from the sensor (transducer), for example, a temperature or a temperature profile. A comparison value can be stored in the evaluation unit, for example, a predefined limit temperature or a temperature profile that is characteristic of a wheel bearing malfunction. The limit temperature or the characteristic temperature profile then represents a comparison value. Based on the comparison of a value or characteristic of the output variable with the comparison value, the warning signal is generated or not generated. In a further preferred embodiment, the evaluation unit is configured to generate the warning signal when the measured quantity, in particular temperature, exceeds a predetermined limit, especially a temperature limit. The warning criterion here is therefore the exceeding of a specific absolute temperature at the measuring point. In a further preferred embodiment, the evaluation unit is configured to generate a warning signal when the measured variable, in particular temperature, exceeds a predetermined limit value, especially a temperature limit value, repeatedly or for a predetermined minimum period. This is based on the understanding that a brief period of significant heating of the wheel bearing does not usually indicate a defect in the wheel bearing, but can be due to normal operation. For example, emergency braking leads to significant heating of the wheel bearing and generally does not signal excessive wear or failure of the wheel bearing. Only if the temperature limit value is exceeded repeatedly or for a longer period is damage to the wheel bearing to be assumed, and the system issues a warning message. According to one embodiment of the invention, the evaluation unit is configured to generate a warning signal when a predetermined characteristic measurement profile, in particular a temperature profile, is detected. Such a characteristic measurement profile can, for example, be the change in the measured quantity over time or a temperature profile over time. A specific temperature profile over time can, for example, be characteristic of damage to the wheel bearing. A characteristic temperature profile can, for example, be a range of changes in the wheel bearing temperature over time. In one embodiment of the invention, the evaluation unit is configured to generate a warning signal when a predetermined or predefinable deviation from a calculated measurement profile, in particular a temperature profile, is exceeded.For example, the temperature profile, i.e., the change in temperature over time (wheel bearing temperature), can be calculated taking into account disturbances (e.g., alternatively or at least partially cumulatively, brake disc temperature, brake pad temperature, air speed, ambient temperature, brake application). This calculated temperature profile is then compared with the actually measured temperature profile. A warning is issued if a deviation is deemed unacceptable. Preferably, the system includes a warning device, in particular an optical and / or acoustic one, which is configured to issue a warning message, for example an optical and / or acoustic one, based on the warning signal generated by the evaluation unit (signaling a warning situation, for example to the driver of the vehicle or another person). The warning device can, for example, have a transparent cutout in the area of ​​the wheel, in particular a wheel cover, which can be backlit. In this way, for example, a lighting device, in particular a stationary (non-rotating) one, can be arranged in the area of ​​an axle, in particular a stationary one, which backlit the transparent cutout in the wheel cover. A light guide can be fixedly mounted and illuminate or backlit part or all of the wheel cover.The warning device may include a warning element, particularly a visual one, integrated into the wheel cover, wheel hub, or rim. Additionally or alternatively, another perceptible warning message, such as an audible warning, may be emitted. The warning is triggered, in particular, when defined warning criteria are exceeded. Preferably, at least one first transmission device is provided for transmitting the output signal from the sensor to the evaluation device. The transmission device can, for example, comprise a cable or a transmission module for wireless data transmission. Furthermore, it is preferred that at least one second transmission device is provided for transmitting data between the evaluation unit and the warning device. Communication between the evaluation unit and the warning device (e.g., a display) can be wireless (Bluetooth, ZigBee), for example. It is also possible for communication to take place via a bus system (e.g., CAN bus). In another embodiment, communication between the evaluation unit and the warning device occurs via a data line. The communication can also be bidirectional, for example, to allow a user to confirm a warning message and send it back to the evaluation unit. In a particularly preferred embodiment, communication between the evaluation unit and the warning device occurs via an electronic braking system (EBS), which is already installed in many vehicles.In an electronic braking system, the brake cylinders are controlled by electronic signals. The brake cylinders then adjust the required brake pressure according to the received control signals. The desired deceleration is initiated by the driver by applying the brakes and is electronically transmitted to the other components of the braking system, in particular the brake cylinders. According to the invention, the communication system of the electronic braking system can also be used for communication between the evaluation unit and the warning device. The warning device, or alerting device, can be permanently integrated into the vehicle, for example, the tractor unit of a commercial vehicle. The warning device can include a display device, such as a screen, and / or an input device, such as buttons, rotary knobs, or a touchpad. It is advantageous that the system's at least one sensor is located in the area of ​​an axle head. The axle head, i.e., the axial end of the vehicle axle (which is stationary), is in close proximity to the wheel bearing, thus enabling precise measurement of the wheel bearing temperature. Furthermore, the sensor can be positioned on a stationary (non-rotating) component, significantly reducing installation and maintenance effort. In principle, it is also possible to position the sensor at any point along the axle and correct the measured temperature based on the distance to the wheel bearing (heat losses). The system's at least one evaluation unit is preferably arranged on or along the vehicle's axle, particularly in the area of ​​the axle head. Alternatively, the evaluation unit can also be mounted, for example, on the vehicle's steering linkage. The sensor and / or the evaluation unit can, for example, be mounted on the axle head, e.g., on an axle nut. Another embodiment of the invention provides for multiple sensors, each arranged, for example, in the area of ​​an axle head, and for each sensor to be assigned an evaluation unit and / or a warning device. The individual sensors are preferably assigned to their own wheel bearings or axles or axle systems. In this decentralized approach, temperature measurement, evaluation, and, if applicable, the display (warning message) are performed independently of one another at the wheel bearings, axles, or axle systems. In this approach, the warning message is preferably signaled by a display in the area of ​​the respective wheel, in particular on a wheel cap, wheel hub, or rim. According to the invention, several sensors are provided, which can, for example, each be arranged in the area of ​​an axle head, with a central warning device being present which is configured to output warning messages related to the sensors. With this central approach, the acquisition of the measured variable is therefore preferably decentralized (e.g., at several axle heads). The evaluation devices can also be arranged decentrally, for example, at the axle heads. Alternatively, a central evaluation device can be provided which receives and evaluates the output variables of the sensors. The central warning device receives either the warning signals from the decentralized evaluation devices or a warning signal generated by the central evaluation device and is preferably arranged away from the wheels at a central position of the vehicle (for example, in or on the driver's cab), trailer, or away from the vehicle or trailer (strategically advantageous or(Easily accessible location). It is preferred that a triggered warning signal remains permanently stored in memory or can only be deleted after authorization by an authorized person. For example, a triggered warning signal can be permanently stored in a non-erasable memory. Alternatively, it is possible that a triggered warning signal can be deleted by the driver or another person. For this purpose, security measures can be integrated into the system to restrict the group of people who can do so. For example, it may be necessary to enter a code or provide authentication to delete the warning signal. It is also possible that while the warning message (e.g., audible / visual) can be switched off (deleted), the underlying (electrical) warning signal remains stored in the system. Deleting / resetting the warning message can be done, for example, via an input device (e.g., a button) integrated into the system.It is also conceivable that the warning message could be deleted / reset via wireless communication, especially a remote control. The invention is further described below with reference to preferred embodiments, which are illustrated in the accompanying schematic figures. The figures show: Fig. 1: a schematic representation of a first embodiment of the invention; Fig. 2: a schematic representation of a second embodiment of the invention; and Fig. 3: an axle system of a vehicle with an inventive design for detecting and evaluating a wheel bearing temperature. Identical or equivalent components are marked with the same reference symbols in all figures. Fig. 1 shows a first embodiment of a system 10 for detecting and evaluating a wheel bearing temperature on an axle system 50. The axle system 50, shown in a highly abstracted form, comprises a first axle 52, a second axle 54, and a third axle 56. The system 10 for detecting and evaluating a wheel bearing temperature is arranged on the axle system 50. The system 10 includes several sensors 20 for temperature detection. The sensors 20 are each arranged in the area of ​​a wheel bearing 60 (see Fig. 5) at one axial end of the respective axle. In the illustrated case with three axles and six wheel bearings, six sensors 20 are present. In principle, however, additional sensors can also be arranged. The number of axles and the number of wheels per axle can, of course, also be larger or smaller. The sensors 20 (measuring elements) detect a temperature as an input 18 and output an electrical signal 22 in response to the input 18. The sensors 20 can be, for example, semiconductor elements (semiconductor temperature sensors) or thermocouples. The output 22 can be, for example, an electric current, an electric voltage, or a digital signal. The output 22 is transmitted to an evaluation unit 30, for example, a control unit. For this purpose, initial transmission devices 26, such as power or data cables, are provided. The evaluation unit 30 evaluates the output 22 by, for example, comparing the measured temperature value with predefined reference values ​​or comparing a measured temperature profile (time-dependent temperature change) with a predefined or calculated temperature profile. As a result of this comparison, the evaluation unit 20 triggers a warning signal 32 if a warning situation is detected based on the comparison. The warning signal 32 is transmitted by means of a second transmission unit 36 ​​to a warning device 40, for example, a light element, a display, or an acoustic warning element. The warning device 40 then issues a warning message 42 that is perceptible to a person, in particular a visual and / or acoustic warning message. The illustrated system 10 comprises a separate measuring chain for each wheel bearing 60, from temperature measurement to evaluation and warning. The individual sensors 20, evaluation units 30, and warning devices 40 are preferably arranged along the axis 52, 54, and 56, respectively, with the warning device 40, in particular an optical one, being located at the outer end of the axis so that it can be perceived by a user (person) in the area of ​​the wheel, in particular on a hubcap. Fig. 2 shows a second embodiment of a system 10 for detecting and evaluating the temperature of a wheel bearing on an axle system 50. As in the embodiment according to Fig. 1, the respective sensors 20 are arranged in the area of ​​the individual wheel bearings 60 on the axle, in particular on the axle head. The output variables 22 are transmitted via corresponding transmission devices 26 to a central evaluation unit 30, for example, a control unit. The central evaluation unit evaluates the detected temperatures and, if a warning situation exists for at least one of the wheel bearings 60, outputs a warning signal 32. The warning signal 32 is transmitted via a second transmission device 36 to an optical and / or acoustic warning device 40. The warning device 40 can, for example, be a display located in a vehicle cabin. The warning device 40 triggers a warning message, for example, an acoustic and / or optical warning message. Fig. 3 shows an axle system 50 of a vehicle, in particular a commercial vehicle, with a system 10 arranged thereon, which is designed according to Fig. 2 (central attachment). The temperature sensors 20 are located in the area of ​​the axle heads of axles 52, 54, and 56. The temperatures measured are transmitted as output 22 via first transmission devices 26 to a central evaluation unit 30, which is mounted on one of the axles 52, 54, or 56. The evaluation unit 30 transmits any generated warning signal 32, e.g., wirelessly, via a second transmission device 36 to a warning device 40, for example, a display in the vehicle cabin. For clarity, the left wheels of the axle system 50 are not shown in Fig. 3. The basic concept of the invention, namely the acquisition and evaluation of a measured value and the signaling of a warning situation to the driver or another person, can, for example, also be applied to other measured variables besides wheel bearing temperature, such as tire pressure. Overall, the evaluation of the measured variable according to the invention by a central or several decentralized control units not only captures and displays the temperature, but also detects a warning situation and signals it with a warning message. The warning situation can thus be perceived by a user almost without delay.

Claims

System for acquiring and evaluating a measured quantity of at least one component of a vehicle, comprising at least one sensor (20) for acquiring a measured quantity of at least one component of the vehicle and for outputting an output quantity (22), and at least one evaluation unit (30) for evaluating the output quantity (22) and for generating a warning signal (32) depending on the evaluation of the output quantity (22) based on at least one defined warning criterion, wherein the measured quantity is a temperature, wherein the component of the vehicle is a wheel bearing, wherein the evaluation unit (30) is configured to generate the warning signal (32) when a predetermined, characteristic measured quantity profile is detected and / or when a predetermined deviation from a calculated measured quantity profile is exceeded, wherein several sensors (20) are provided, wherein a central warning unit (40) is present, which is configuredto issue warning messages (42) relating to the sensors (20), wherein at least one sensor (20) of the system is mounted on an axle head. System according to claim 1, wherein the evaluation device (30) is configured to perform a comparison of at least one value of the output variable (22) with a comparison value. System according to one of the preceding claims, wherein the evaluation device (30) is configured to generate the warning signal (32) when the detected measured quantity exceeds a predetermined limit value and / or when the detected measured quantity exceeds a predetermined limit value multiple times or for a predetermined minimum period of time. System according to one of the preceding claims, wherein the system includes an optical and / or acoustic warning device (40) which is configured to issue a warning message (42) based on the warning signal (32) generated by the evaluation unit. System according to claim 4, wherein at least one transmission device (36) is provided for transmitting data between the evaluation device (30) and the warning device (40). System according to one of the preceding claims, wherein the at least one evaluation device (30) of the system is arranged in the area of ​​an axle head. System according to one of the preceding claims, wherein several sensors (20) are provided and wherein each sensor (20) is assigned an evaluation device (30) and / or a warning device (40). System according to one of the preceding claims, wherein a triggered warning signal (32) remains permanently stored in a memory or can only be deleted after authorization by an authorized person. Method for acquiring and evaluating a measured quantity of at least one component of a vehicle, comprising the steps of: acquiring a measured quantity of at least one component of the vehicle and outputting an output quantity (22), evaluating the output quantity (22), and generating a warning signal (32) depending on the evaluation of the output quantity (22) based on at least one defined warning criterion, wherein the measured quantity is a temperature, wherein the component of the vehicle is a wheel bearing, wherein the warning signal (32) is generated when a predetermined characteristic measured quantity profile is detected and / or when a predetermined deviation from a calculated measured quantity profile is exceeded, wherein several sensors (20) are provided, wherein a central warning device (40) is provided which is configured to output warning messages (42) relating to the sensors (20), and wherein the at least one sensor (20) of the system is mounted on an axle head.

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