System and method for measuring valve lift and for detecting a fault in a valve actuator based on the valve lift

Patent metadata

Field	Value
Publication number	US-9506381-B2
Application number	US-201414260608-A
Country	US
Kind code	B2
Filing date	Apr 24, 2014
Priority date	Jan 31, 2014
Publication date	Nov 29, 2016
Grant date	Nov 29, 2016

Abstract

A system according to the principles of the present disclosure includes a valve lift determination module and a fault detection module. The valve lift determination module determines valve lift based on at least one of a first period when a valve is open and N differences between a first value of a valve lift signal generated by a valve lift sensor when the valve is closed and a second value of the valve lift signal when the valve is open, wherein N is an integer greater than one. The fault detection module detects a fault in a valve actuator based on the valve lift.

First claim

What is claimed is:

1. A system comprising:
a valve lift determination module that:
obtains samples of a valve lift signal generated by a valve lift sensor;
determines whether a valve is open or closed based on a magnitude of the samples;
determines a first period for which the valve is open based on a number of the samples obtained while the valve is open and a corresponding sampling rate; and
determines valve lift based on the first period, wherein the valve lift is an amount by which the valve is lifted; and

a fault detection module that detects a fault in a valve actuator based on the valve lift.

2. The system of claim 1 wherein the fault detection module detects a fault in the valve actuator when the valve lift is outside of a valve lift range.

3. The system of claim 2 further comprising a valve control module that controls the valve actuator, wherein the fault detection module determines the valve lift range based on a valve lift command that the valve control module sends to the valve actuator.

4. The system of claim 1 wherein the valve includes at least one of an intake valve of an engine and an exhaust valve of the engine.

5. The system of claim 1 further comprising a valve control module that controls the valve actuator based on a default state when a fault in the valve actuator is detected.

6. The system of claim 1 wherein the valve lift determination module:
determines a second period for which the valve is closed based on a number of the samples obtained while the valve is closed and the sampling rate; and
determines the valve lift based on the first period for which the valve is open and the second period for which the valve is closed.

7. The system of claim 6 wherein the valve lift determination module determines the valve lift based on a ratio of the first period to a sum of the first period and the second period.

8. The system of claim 7 further comprising a sensor voltage determination module that determines an output voltage of the valve lift sensor when the valve is closed based on a predetermined number of samples that are taken from the valve lift signal over a predetermined period and that are greater than other samples taken from the valve lift signal during the predetermined period.

9. The system of claim 8 further comprising a sensor voltage normalization module that normalizes the output voltage of the valve lift sensor by multiplying the output voltage by a ratio of a predetermined voltage to the output voltage when the valve is closed, wherein the valve lift determination module determines whether the valve is open or closed based on the normalized output voltage.

10. The system of claim 8 wherein the valve lift determination module:
determines first and second thresholds based on the output voltage when the valve is closed;
determines that the valve is open when the output voltage of the valve lift sensor is less than the first threshold; and
determines that the valve is closed when the output voltage is greater than the second threshold, wherein the second threshold is greater than the first threshold.

11. The system of claim 1 further comprising an engine actuator control module that adjusts operation of an engine actuator based on whether a fault in the valve actuator is detected.

12. A method comprising:
obtaining samples of a valve lift signal generated by a valve lift sensor;
determining whether a valve is open or closed based on a magnitude of the samples;
determining a first period for which the valve is open based on a number of the samples obtained while the valve is open and a corresponding sampling rate;
determining valve lift based on the first period, wherein the valve lift is an amount by which the valve is lifted; and
detecting a fault in a valve actuator based on the valve lift.

13. The method of claim 12 further comprising detecting a fault in the valve actuator when the valve lift is outside of a valve lift range.

14. The method of claim 13 further comprising determining the valve lift range based on a valve lift command that is sent to the valve actuator.

15. The method of claim 12 wherein the valve includes at least one of an intake valve of an engine and an exhaust valve of the engine.

16. The method of claim 12 further comprising controlling the valve actuator based on a default state when a fault in the valve actuator is detected.

17. The method of claim 12 further comprising:
determining a second period for which the valve is closed based on a number of the samples obtained while the valve is closed and the sampling rate; and
determining the valve lift based on the first period for which the valve is open and the second period for which the valve is closed.

18. The method of claim 17 further comprising determining the valve lift based on a ratio of the first period to a sum of the first period and the second period.

19. The method of claim 18 further comprising determining an output voltage of the valve lift sensor when the valve is closed based on a predetermined number of samples that are taken from the valve lift signal over a predetermined period and that are greater than other samples taken from the valve lift signal during the predetermined period.

20. The method of claim 19 further comprising:
normalizing the output voltage of the valve lift sensor by multiplying the output voltage by a ratio of a predetermined voltage to the output voltage when the valve is closed; and
determining whether the valve is open or closed based on the normalized output voltage.

21. The method of claim 19 further comprising:
determining first and second thresholds based on the output voltage when the valve is closed;
determining that the valve is open when the output voltage of the valve lift sensor is less than the first threshold; and
determining that the valve is closed when the output voltage is greater than the second threshold, wherein the second threshold is greater than the first threshold.

22. The method of claim 12 further comprising adjusting operation of an engine actuator based on whether a fault in the valve actuator is detected.

23. A system comprising:
a valve lift determination module that:
obtains L samples of a valve lift signal when a valve is closed;
obtains M samples of the valve lift signal when the valve is open; and
determines valve lift based on N differences between the L samples of the valve lift signal and the M samples of the valve lift signal, wherein the valve lift is an amount by which the valve is lifted, and L, M, and N are integers greater than one; and

a fault detection module that detects a fault in a valve actuator based on the valve lift.

24. The system of claim 23 wherein the valve lift determination module determines the valve lift based on a sum of the N differences between the L samples of the valve lift signal and the M samples of the valve lift signal.

25. The system of claim 23 further comprising an engine actuator control module that adjusts operation of an engine actuator based on whether a fault in the valve actuator is detected.

26. A method comprising:
obtaining L samples of a valve lift signal when a valve is closed;
obtaining M samples of the valve lift signal when the valve is open;
determining valve lift based on N differences between the L samples of the valve lift signal and the M samples of the valve lift signal, wherein the valve lift

Assignees

• Gm Global Tech Operations Llc

Inventors

• Kubani Ronald J
• Feldmann Scott T
• Dibble Donovan L

Classifications

• F01L2013/11

  Sensors for variable valve timing · CPC title

• F01L13/0015 Primary

  for optimising engine performances by modifying valve lift according to various working parameters, e.g. rotational speed, load, torque · CPC title

• F01L1/185 Primary

  Overhead end-pivot rocking arms · CPC title

• F01L2013/118

  Valve lift · CPC title

• F01L3/24

  Safety means or accessories, not provided for in preceding sub- groups of this group · CPC title