DEVICE FOR DETERMINING A TEMPERATURE

Abstract

A device for determining temperature information from a sensor device, which is configured to transmit sensor information by time-limited electrical pulses according to a defined protocol, including: a data processing unit configured to perform the following: retrieving reference data relating to a relationship between a pulse duration of the electrical pulses and thermal effects in the sensor device; measuring the pulse duration at at least one of the electrical pulses; and determining the temperature information on the basis of at least one result of the measurement and the reference data. Also described are a related sensor system, a related vehicle, related methods, and a computer readable medium.

Claims

1-11. (canceled)

12. A device for determining temperature information from a sensor device, which is configured to transmit sensor information by time-limited electrical pulses according to a defined protocol, comprising: a data processing unit configured to perform the following: retrieving reference data relating to a relationship between a pulse duration of the electrical pulses and thermal effects in the sensor device; measuring the pulse duration at at least one of the electrical pulses; and determining the temperature information on the basis of at least one result of the measurement and the reference data.

13. The device of claim 12, wherein the data processing unit is configured to determine the temperature information based on reference data, wherein the reference data has at least one of the following characteristics: specifying, for at least one pulse duration of the electrical pulses, a temperature assigned to the pulse duration, and/or specifying a linear relationship between a temperature and the pulse duration of the electrical pulses, and/or specifying a quantized or non-linear relationship between a temperature and the pulse duration of the electrical pulses, and/or specifying sensor-dependent correction data which define, for the sensor device, deviations from a predefined relationship between a temperature and the pulse duration of the electrical pulses.

14. The device of claim 12, wherein the data processing unit is configured, after determining the temperature information, to compare this temperature information with at least one threshold value and to trigger at least one alarm after the threshold value has been exceeded.

15. A sensor system, comprising: a speed sensor, for determining a speed in a vehicle, which is configured to transmit sensor information from the speed sensor by time-limited electrical pulses according to a defined protocol; and a device for determining temperature information from the speed sensor or from an environment thereof, wherein the device includes: a data processing unit configured to perform the following: retrieving reference data relating to a relationship between a pulse duration of the electrical pulses and thermal effects in the sensor device; measuring the pulse duration at at least one of the electrical pulses; and determining the temperature information on the basis of at least one result of the measurement and the reference data.

16. The sensor system of claim 15, wherein sensor information is transmitted according to a protocol which does not provide for any transmission of temperature information.

17. A vehicle, comprising: at least one sensor system, including: a speed sensor, for determining a speed in a vehicle, which is configured to transmit sensor information from the speed sensor by time-limited electrical pulses according to a defined protocol; and a device for determining temperature information from the speed sensor or from an environment thereof, wherein the device includes: a data processing unit configured to perform the following: retrieving reference data relating to a relationship between a pulse duration of the electrical pulses and thermal effects in the sensor device; measuring the pulse duration at at least one of the electrical pulses; and determining the temperature information on the basis of at least one result of the measurement and the reference data.

18. The vehicle of claim 17, wherein the data processing unit includes a predefined systematic correction in the determination of the temperature information to determine the temperature at a predefined position in the vehicle in the vicinity of the speed sensor.

19. A method for measuring temperature information from a sensor device, which is configured to transmit sensor information to a receiver by time-limited electrical pulses according to a defined protocol, wherein the receiver has reference data relating to a relationship between a pulse duration of the electrical pulses and thermal effects in the sensor device, the method comprising: measuring the pulse duration at at least one of the electrical pulses; and determining the temperature information from at least the measured pulse duration and the reference data.

20. A method for generating reference data relating to a relationship between a pulse duration of time-limited electrical pulses and thermal effects for a sensor device, which is configured to transmit sensor information to a receiver by the electrical pulses and is heated during a production method and subsequently cooled, the method comprising: transmitting sensor information from the sensor device to the receiver, and, at the same time, continuously measuring at least one temperature in the sensor device during heating and subsequent cooling; gauging the relationship between the pulse duration and thermal effects in the sensor device based on the transmission of sensor information and the measurement of the temperature in the sensor device; and determining the reference data from at least one result of the gauging process.

21. The method of claim 20, wherein the determination of the reference data includes at least one of the following: averaging results of repeated gauging of the relationship between the pulse duration and the thermal effects for a sensor device, averaging results of a process of gauging the relationship between the pulse duration and the thermal effects for a plurality of sensor devices, and/or determining a functional dependence for the relationship between the pulse duration and the thermal effects by an equalization calculation.

22. A non-transitory computer readable medium having a computer program, which is executable by a processor, comprising: a program code arrangement having program code for measuring temperature information from a sensor device, which is configured to transmit sensor information to a receiver by time-limited electrical pulses according to a defined protocol, wherein the receiver has reference data relating to a relationship between a pulse duration of the electrical pulses and thermal effects in the sensor device, by performing the following: measuring the pulse duration at at least one of the electrical pulses; and determining the temperature information from at least the measured pulse duration and the reference data.

23. The sensor system of claim 15, wherein sensor information is transmitted according to the protocol of “Requirement Specifications for Standardized Interface for Wheel Speed Sensors with Additional Information—AK-Protocol Version: 4.0”.

Description

BRIEF DESCRIPTIONS OF THE DRAWINGS

[0061] FIG. 1 shows a diagram for an exemplary embodiment of the present invention.

[0062] FIG. 2 shows a typical pulse sequence according to the AK protocol.

[0063] FIG. 3 shows results of a measurement series for the dependence of a pulse width on a temperature in the sensor device.

[0064] FIG. 4 shows a situation of a speed sensor in a vehicle.

[0065] FIG. 5 shows steps of a method for measuring temperature information from a sensor using pulse widening.

[0066] FIG. 6 shows steps of a method for generating reference data.

DETAILED DESCRIPTION

[0067] FIG. 1 schematically shows a device 100 for determining temperature information 130 from a sensor device 200. The sensor device 200 is electrically connected to the device 100 for the purpose of transmitting sensor information by time-limited electrical pulses 210 according to a defined protocol. The device 100 comprises a data processing unit 110 which has access to reference data 120 relating to the dependence of a pulse duration 215 on a temperature in the sensor device 200. In the diagram illustrated, the reference data are stored in a memory of the data processing unit itself, but may also be stored at a different location in the device, for example. The data processing unit 110 measures the pulse duration 215 at at least one of the electrical pulses 210. It retrieves the reference data 120 in order to determine the temperature information 130 on the basis of the result of the measurement and the reference data 120.

[0068] FIG. 2 shows a typical sequence of electrical pulses 210 according to the AK protocol which is used, in particular, to transmit sensor information from wheel sensors 200 (not in the image here) for wheels in vehicles. A speed sensor 200 measures a speed of a wheel, typically at a rotor 330 (not illustrated here), for instance on the basis of passes of spokes or teeth. In this case, the passes cause speed pulses 211 at a rate proportional to the speed of the wheel.

[0069] The pulses 210 transmitted by the speed sensor 200 are current pulses. Above a basic current intensity 217, transmission is effected using two current intensities. A high current intensity 219—for example 28 mA—indicates a speed pulse 211 at the start of a pulse sequence or data packet. The speed pulse 211 is followed, with a lower current intensity 218 (the output current), by nine bits of information, with the bit cell number being numbered from 0 to 8. In this case, the electrical pulses 210 typically transmit the bits using Manchester encoding. The bit cells are limited in terms of time by a duration (often denoted t.sub.p in the literature) which is typically determined by the duration or width of the speed pulse 211. Inside the bit cells, bits are coded by changing the current intensity: a logic 1 is indicated by a rising current intensity and a logic 0 is indicated by a falling current intensity, for example. The information content of the protocol typically does not comprise any temperature information from the speed sensor 200 or its environment.

[0070] The duration of the speed pulse 211 or of the bit cells can be used here as the pulse duration 215 and can be measured in the data processing unit 110 (not illustrated here). It is in a range of 50 μs±10 μs, depending on the temperature in the speed sensor 200. Speed sensors 200 in vehicles normally operate in environments which exhibit temperatures between approximately −40° C. and approximately 200° C. A resolution of approximately 12° C. per microsecond can therefore be achieved, for example, if the temperature range is utilized fully.

[0071] For advantageous use of the temperature sensing presented here, modifications of the coding or other protocols do not constitute an obstacle. Only a pulse duration 215 must be able to be measured in order to determine temperature information 130.

[0072] FIG. 3 shows an example of measurement results 30 for the dependence of a pulse duration 215 of the AK protocol on the temperature for a speed sensor 200 (not illustrated here in each case), as is used in the automotive sector. Illustrated alongside the measurement results 30 are a linearization straight line 60 calculated from said results and a temperature warning threshold 70.

[0073] The linearization straight line 60 has been determined by an equalization calculation from the measurement results 30 and may be used, for example, as a characteristic curve for the speed sensor 200 or another speed sensor of the same configuration. The linearization straight line 30 can also be replaced, in particular, with a more accurately adapted curve, for instance a polynomial.

[0074] If the determined temperature 130 exceeds the warning threshold 70 during operation of the speed sensor 200, the data processing unit 110 or the device 100 for determining a temperature can report this to a superordinate system, for example, or can output an alarm or a warning, for example.

[0075] FIG. 4 shows a situation of a speed sensor 200 on a wheel for a brake system in a vehicle. A cross section through a part of the wheel axle 310 and of the wheel carrier or of the wheel bearing unit 320 in a plane comprising the wheel axis of rotation can be seen. Depicted on the right-hand side is the sensor device in the form of a speed sensor 200 which determines a speed of the wheel by virtue of a rotor 330 punched from sheet metal, for example, passing through openings 335 and forwards it to an electronic control unit 100, not illustrated here, for instance the anti-lock braking system. The bearing 325 is in the form of a two-row tapered roller bearing or angular ball bearing, for example.

[0076] In order to monitor a temperature in the bearing 325, a data processing unit 110, not illustrated here, in the electronic control unit 100 can determine the temperature in the speed sensor 200 close to the bearing. Furthermore, the data processing unit 110 may also be configured infer a temperature in the bearing by predefined correction of this temperature. In contrast, a temperature measurement, for example by measurement and coded transmission in the speed sensor 200 itself or by a further sensor, would be complicated and cost-intensive on account of the necessary change to the transmission protocol or the use of further hardware in view of the complexity of the wheel module.

[0077] FIG. 5 shows steps of a method for measuring temperature information 130 from a sensor device 200 which is configured to transmit sensor information to a receiver by time-limited electrical pulses 210 according to a defined protocol, wherein the receiver has reference data 120 relating to a relationship between a pulse duration 215 of the electrical pulses and thermal effects in the sensor device 200. A first characterizing step of the method involves measuring S10 the pulse duration 215 at least one of the electrical pulses 210. This measurement S10 is advantageously carried out in the receiver. The second characterizing step of the method involves determining S20 the temperature information 130 from at least the measured pulse duration 215 and the reference data 120. The determination may comprise further corrections in this case.

[0078] FIG. 6 shows steps of a method for generating reference data for a sensor device 200, which is configured to transmit sensor information to a receiver by time-limited electrical pulses 210 of an electrical current and is encapsulated with a plastic during a production method, is heated in the process and is subsequently cooled, relating to a relationship between a pulse duration 215 of the electrical pulses 210 and thermal effects in the sensor device 200. The sensor device 200 is connected, during the production method, to a provided receiver which is configured to receive the sensor information and gauge the pulse duration 215. Characterizing steps first of all then comprise repeatedly transmitting S50 sensor information from the sensor device 200 to the receiver while, at the same time, continuously measuring at least one temperature in the sensor device 200 during heating during the encapsulation with the plastic and subsequent cooling. As the next step, the data obtained are used to gauge S60 or determine the relationship between the pulse duration 215 and thermal effects in the sensor device 200 on the basis of the transmission S50 of the sensor information and the measurement of the temperature in the sensor device 200. Finally, the reference data 120 are determined S70 from at least one result of the gauging process S60.

[0079] When transmitting S50 sensor information and measuring a temperature in the sensor device 200, the content of the information is at least not necessarily important. The reference data 120 may be basic data, for instance for a characteristic curve of the relationship between the pulse width 215 and the temperature for the sensor type and/or sensor-specific data.

[0080] The features of the invention which are disclosed in the description, the claims and the figures may be important, both individually and in any desired combination, for the implementation of the invention.

THE LIST OF REFERENCE SIGNS IS AS FOLLOWS

[0081] 30 Measurement results [0082] 60 Calculated linearization straight line [0083] 70 Warning threshold [0084] 100 Device for determining temperature information [0085] 110 Data processing unit [0086] 120 Reference data [0087] 123 Characteristic curve [0088] 127 Correction data [0089] 130 Temperature information [0090] 200 Sensor device [0091] 210 Electrical pulses [0092] 211 Speed pulse [0093] 215 Pulse duration [0094] 217 Basic current [0095] 218 Low current [0096] 219 High current [0097] 310 Wheel axle [0098] 320 Wheel bearing unit [0099] 325 Wheel bearing [0100] 330 Rotor [0101] 335 Rotor opening [0102] S10 Measure the pulse duration [0103] S20 Determine the temperature information [0104] S50 Transmit sensor information and measure a temperature in the sensor device [0105] S60 Gauge the relationship between temperature and pulse width [0106] S70 Determine the reference data