Method for controlling a piezo-actuated fuel-injection valve

• US 20040168511A1
• Filed: 03/08/2004
• Published: 09/02/2004
• Est. Priority Date: 09/14/2001
• Status: Active Grant

• Current Assignee: Continental Automotive GmbH (Continental AG)
• Original Assignee: Siemens AG
• Inventors: Wolpert, Hartmut, Przymusinski, Achim
• Granted Patent: US 7,123,021 B2
• Time in Patent Office: Days
• US Class Current: 73/132
• CPC Class Codes: G01D 3/08 with provision for safeguarding the apparatus, e.g. against abnormal operation, against breakdown
• CPC Class Codes: G01D 5/1655 more than one point of contact or actuation on one or more tracks

Abstract

In a method for the diagnosis of a sensor, in particular a pedal-travel sensor of a motor vehicle, a first signal (S1) and at least one second equivalent signal (S2) are delivered. If the second signal (S2) is time-delayed with respect to the first signal (S1), at least the previous curve of the first signal (S1) and/or the previous curve of the second signal (S2) is taken into account.

Claims

1. A method for diagnosis of a sensor, especially a sensor for generating pedal travel values for a motor vehicle, comprising the steps of:

receiving a first signal and at least an equivalent value second signal from the sensor, and

at least when the second signal exhibits a time delay compared to the first signal, taking into account the previous curve of the first signal and/or the previous curve of the second signal.

2. The method in accordance with claim 1, wherein the process of taking account of the previous timing curve of the first signal includes determining a rate of change of the first signal.

3. The method in accordance with claim 2, wherein the rate of change of the first signal is determined by determining the amount of the difference between a first value of the first signal and an earlier second value of the first signal.

4. The method in accordance with claim 1, wherein the process of taking account of the previous timing curve of the second signal includes determining a rate of change of the second signal.

5. The method in accordance with claim 4, wherein the rate of change of the second signal is determined by determining the amount of the difference between a first value of the second signal and an earlier second value of the second signal.

6. The method in accordance with claim 1, wherein, especially for detection of low frequency faults, the amount of the difference between a value of the first signal and a value of the second signal is compared with a first threshold value.

7. The method in accordance with claim 6, wherein the first threshold value is an adaptive threshold value.

8. The method in accordance with claim 7, wherein the adaptation of the first threshold value is undertaken depending on the rate of change of the first signal and/or depending on the rate of change of the second signal.

9. The method in accordance with claim 8, wherein, for adaptation of the first threshold value, the sum of the rate of change maxima determined at different points in time and if necessary of a constant is determined.

10. The method in accordance with claim 1, wherein, especially for detection of high-frequency faults, a filtered value determined depending on the previous curve of the first signal and/or on the previous curve of the second signal, is compared with a second threshold value.

11. The method in accordance with claim 10, wherein the second threshold value is specified as a fixed value.

12. The method in accordance with claim 10, wherein determining the filtered value includes a process by which a first rate of change sum is determined from a rate of change of the first signal determined at a first point in time and one or more rates of change of the first signal determined before the first point in time.

13. The method in accordance with claim 10, wherein determining the filtered value includes a process by which a second rate of change sum from a rate of change of the second signal determined at a second point in time and one or more rates of change of the second signal determined before the second point in time.

14. The method in accordance with claim 12, wherein determining the filtered value includes a process by which the difference between the first rate of change sum and the second rate of change sum is determined.

15. The method in accordance with claim 14, wherein determining the filtered value includes a process by which the difference between the first rate of change sum and the second rate of change sum is subjected to low pass filtering.

16. The method in accordance with claim 15, wherein determining the filtered value includes a process by which the amount of the low pass filtered difference between the first rate of change sum and the second rate of change sum is formed.

17. A device for diagnosis of a sensor, especially a sensor for generating pedal travel values for a motor vehicle, comprising:

means for receiving a first signal and at least an equivalent value second signal from the sensor, and

an evaluation unit for determining whether the second signal exhibits a time delay compared to the first signal, in which case the device takes the previous curve of the first signal and/or the previous curve of the second signal into account.

18. A device for diagnosis of a sensor, especially a pedal travel sensor of a motor vehicle which delivers a first signal and at least one second equivalent signal wherein at least when the second signal exhibits a time delay compared to the first signal, the device takes account of the previous curve of the first signal and/or the previous curve of the second signal.

19. The device in accordance with claim 18, comprising means for determining the first rate of change which determine a rate of change of the first signal, to take account of the previous time curve of the first signal.

20. The device in accordance with claim 19, wherein the first means of determining the rate of change determines the rate of change of the first signal by determining the amount of the difference from a first value of the first signal and an earlier second value of the first signal.

21. The device in accordance with claim 18, comprising a second means for determining the rate of change of the second signal, to take account of the previous timing curve of the second signal.

22. The device in accordance with claim 21, wherein the second means for determining that rate of change determines the rate of change of the second signal by determining the amount of the difference between a first value of the second signal and an earlier second value of the second signal.

23. The device in accordance with claim 18, comprising first comparison means which, especially for detection of low-frequency faults, compares the amount of the difference between a value of the first signal and a value of the second signal with a first threshold value.

24. The device in accordance with claim 23, comprising threshold value adaptation means which adapt the first threshold value.

25. The device in accordance with claim 24, wherein the threshold adaptation means adapt the first threshold depending on the rate of change of the first signal and/or depending on the rate of change of the second signal.

26. The device in accordance with claim 25, wherein the means for adapting the threshold value, to adapt the first threshold value, determine the sum of the different rate of change maxima determined at different points in time and if necessary of a constant.

27. The device in accordance with claim 18, comprising a second means of comparison which, especially for detection of high-frequency faults, compares a filtered value determined depending on the previous curve of a first signal and/or the previous curve of the second signal with a second threshold value.

28. The device in accordance with claim 27, comprising means of storing threshold values which specifies the second threshold value as a fixed value.

29. The device in accordance with claim 27, comprising a first means of summation which, to determine the filtered value, determines a first rate of change sum from a rate of change of the first signal determined at a first point in time and one or more rates of change of the first signal determined before the first point in time.

30. The device in accordance with claim 27, comprising a second means of summation which, to determine the filtered value, determines a second rate of change sum from a rate of change of the second signal determined at a first point in time and one or more rates of change of the second signal determined before the second point in time.

31. The device in accordance with claim 29, comprising subtraction means, which, to determine the filtered value, determine the difference between the first rate of change sum and the second rate of change sum.

32. The device in accordance with claim 31, comprising means of low pass filtering, which, to determine the filtered value, apply low pass filtering to the difference between the first rate of change sum and the second rate of change sum.

33. The device in accordance with claim 32, comprising means for forming the amount which, to determine the filtered value, determines the amount of the low pass filtered difference between the first rate of change sum and the second rate of change sum.