Speed sensor device, speed sensor method, electronic control unit and control method

Patent metadata

Field	Value
Publication number	US-9651572-B2
Application number	US-201414219352-A
Country	US
Kind code	B2
Filing date	Mar 19, 2014
Priority date	Mar 19, 2014
Publication date	May 16, 2017
Grant date	May 16, 2017

Abstract

Embodiments relate to a speed sensor device including a sensor element to provide a sensor signal, a status module to provide status information of the speed sensor device; and a processing module to generate an output signal. The output signal is derived from the sensor signal, if the status information is indicative of a non-critical state of the speed sensor device, and the output signal is a safety message signal having signal edges such that time intervals between subsequent congeneric signal edges are equal to or shorter than a preselected threshold, if the status in-formation is indicative of a critical state of the speed sensor device. An Electronic Control Unit (ECU) includes an interface for receiving a signal having signal edges from a speed sensor device and a processing unit to analyze time intervals between subsequent congeneric signal edges. The processing unit is configured to determine a non-critical state of the speed sensor device, if the time intervals are higher than a preselected thresh-old, and to determine a critical state of the speed sensor device, if the time intervals between two subsequent congeneric signal edges are equal to or shorter than the preselected threshold.

First claim

The invention claimed is:

1. A speed sensor device, comprising:
a sensor element to provide a sensor signal;
a status module to provide status information of the speed sensor device; and
a processing module to generate an output signal, wherein the output signal is derived from the sensor signal, if the status information is indicative of a non-critical state of the speed sensor device, and wherein the output signal is a safety message signal having signal edges such that time intervals between subsequent congeneric signal edges are equal to or shorter than a preselected threshold, if the status information is indicative of a critical state of the speed sensor device.

2. The speed sensor device of claim 1 , wherein the time intervals between subsequent congeneric signal edges of the safety message signal have a length determined as quotient of the preselected threshold and n, wherein n is a natural number higher than 1.

3. The speed sensor device of claim 1 , wherein the signal derived from the sensor signal comprises signal edges such that time intervals between subsequent congeneric signal edges of the derived signal are longer than the preselected threshold.

4. The speed sensor device of claim 1 , wherein the sensor signal comprises signal edges and wherein the preselected threshold depends on an application of the speed sensor device and is the longest possible time interval between subsequent congeneric signal edges of the sensor signal, which can not be reached in the corresponding application of the speed sensor device.

5. The speed sensor device of claim 1 , wherein the preselected threshold is a value in the range from 1/1000 s to 1/5000 s, if the speed sensor device is applied to determine a rotational speed for ABS applications in an automobile.

6. The speed sensor device of claim 1 , wherein the preselected threshold is a value in the range from 1/7000 s to 1/13000 s, if the speed sensor device is applied to determine a rotational speed for transmission applications in an automobile.

7. The speed sensor device of claim 1 , wherein the preselected threshold is predetermined during production of the speed sensor device or selected dependent on the application of the speed sensor device during installation thereof.

8. The speed sensor device of claim 1 , wherein the sensor module is a magnetic field sensor module and the sensor signal is indicative of an oscillating magnetic field indicative of a revolution speed of a rotatable body.

9. The speed sensor device of claim 1 , wherein the status information is determined on the basis of general functional safety tests, of comparison information of redundant paths or of outer parameters.

10. The speed sensor device of claim 1 , wherein the critical state of the speed sensor device is a state in which the speed sensor device is not able to output information of the sensor signal in a reliable way.

11. The speed sensor device of claim 1 , wherein the critical state is indicative of a lack of sufficient supply voltage provided to the speed sensor device or indicative of a bit-error in a storage of the sensor or indicative of an outer parameter.

12. The speed sensor device of claim 1 , wherein the status module is configured to output a status signal having a low level and a high level, wherein one of the low and the high level is indicative of the non-critical state of the speed sensor device and the other of the low and the high level is indicative of the critical state of the speed sensor device.

13. The speed sensor device of claim 1 , wherein the status module is configured to provide status information indicative of a further critical status and the safety message signal is indicative of a type of the critical states.

14. The speed sensor device of the claim 1 , wherein the safety message signal has time intervals between two subsequent disparate signal edges being shorter or longer than half of the time interval between two subsequent congeneric signal edges of the safety message signal, if the state signal is indicative of the critical state.

15. The speed sensor device of the claim 1 , wherein the time interval between two subsequent disparate signal edges of the safety message signal is shorter than 40% or longer than 60% of the time interval between two subsequent congeneric signal edges of the safety message signal, if the state signal is indicative of the critical state.

16. The speed sensor device of the claim 1 , wherein the time intervals between two subsequent disparate signal edges of the safety message signal vary periodically, if the state signal is indicative of the critical state.

17. The speed sensor device of the claim 1 , wherein the safety message signal is provided with an offset compared to the output signal being the sensor signal or derived from the sensor signal.

18. A speed sensor method comprising the acts of: receiving a sensor signal indicative of a sensed physical quantity from a sensor element of a speed sensor device;
providing a status information of the speed sensor device; and
generating an output signal, wherein the output signal is derived from the sensor signal, if the status information is indicative of a non-critical state of the speed sensor device, and wherein the output signal is a safety message signal having signal edges such that time intervals between subsequent congeneric signal edges are equal to or shorter than a preselected threshold, if the status information is indicative of a critical state of the speed sensor device.

19. An electronic control unit comprising: an interface for receiving a signal having signal edges from a speed sensor device, and a processing unit to analyse time intervals between subsequent congeneric signal edges, wherein the processing unit is configured to determine a non-critical state of the speed sensor device, if the time intervals are higher than a preselected threshold, and to determine a critical state of the speed sensor device, if the time intervals between two subsequent congeneric signal edges are equal to or shorter than the preselected threshold.

20. The electronic control unit of claim 19 , wherein the processing unit is configured to differentiate between two or more critical states by analysing time intervals between two subsequent disparate signal edges, the time intervals being shorter than the preselected threshold.

Assignees

• Infineon Technologies Ag

Inventors

• Rasbornig Friedrich

Classifications

• G01P3/489

  Digital circuits therefor · CPC title

• G01M17/013

  Wheels · CPC title

• G01P21/02

  of speedometers · CPC title

• G01P3/00 Primary

  Measuring linear or angular speed; Measuring differences of linear or angular speeds (G01P5/00 - G01P11/00 take precedence; {direction and speed indication G01P13/045}; counting mechanisms G06M) · CPC title

• B60T17/18

  Safety devices; Monitoring · CPC title