System to diagnose variable valve actuation malfunctions by monitoring fluid pressure in a hydraulic lash adjuster gallery

Patent metadata

Field	Value
Publication number	US-9644503-B2
Application number	US-201514695355-A
Country	US
Kind code	B2
Filing date	Apr 24, 2015
Priority date	Jul 22, 2008
Publication date	May 9, 2017
Grant date	May 9, 2017

Abstract

A system for diagnosing malfunctions in a variable valve actuation device. The system has a rocker arm assembly with first and second arms attached at a first end and a hydraulically operated latch assembly to secure the first arm to the second arm when latched. The rocker arm assembly pivots upon a hydraulic lash adjuster and includes a source of pressurized fluid connected to a hydraulic valve providing high or low pressure fluid to the hydraulically-operated latch. The latch may be operated by a remote device. A pressure transducer positioned within the hydraulic lash adjuster (HLA) is adapted to create a signal indicating fluid pressure in the HLA. A control unit coupled to the hydraulic valve and the pressure transducer is adapted to sense engine operating parameters, actuate the hydraulic valve, read the signal from the pressure transducer and identify malfunctions of the rocker arm assembly based upon the signal.

First claim

What is claimed is:

1. A system for diagnosing malfunctions in a variable valve actuation system, wherein the variable valve actuation system comprises a hydraulic lash adjuster (HLA) chamber filled with fluid, the system for diagnosing malfunctions comprising:
a pressure transducer coupled to the HLA chamber adapted to generate a pressure signal indicative of fluid pressure in the HLA chamber, wherein the pressure signal is transmitted to a control unit for determination of whether the variable valve system is malfunctioning; and
wherein the control unit is configured to diagnose a malfunction by comparing a pre-stored pressure signal to the generated pressure signal.

2. The system for diagnosing malfunctions of claim 1 , wherein the control unit is further configured to:
compare the pre-stored pressure signal to the generated pressure signal and, based on said comparison, identify at least one of:
a shift of a pressure event in time;
changes in a rate of occurrence of events;
sudden unexpected pressure transients; and
an overall change in an amplitude of pressure events.

3. The system for diagnosing malfunctions of claim 1 , wherein the control unit is further adapted to:
store information indicating a desired mode of the variable valve actuation system;
generate information of a current mode of the variable valve actuation system from the generated pressure signal;
compare the information of the desired mode to the information of the current mode; and
determine an occurrence of a malfunction of the variable valve actuation system based on the comparison.

4. The system for diagnosing malfunctions of claim 1 , wherein the control unit is further adapted to:
determine a number of malfunctions over a predetermined time period to determine a malfunction rate.

5. The system for diagnosing malfunctions of claim 4 , wherein the control unit is further adapted to:
determine if the malfunction rate exceeds a predetermined malfunction rate.

6. The system of claim 3 , wherein the control unit is further configured to determine the occurrence of the malfunction of the variable valve actuation system as a failure to engage a low lift mode based on the pressure signal indicating the fluid pressure in the HLA chamber is below the pre-stored pressure signal.

7. The system of claim 1 , wherein the control unit is further configured to diagnose the malfunction of the variable valve actuation system based on a speed of an engine operationally coupled to the variable valve actuation system being below 3500 RPM.

8. The system of claim 7 , wherein the control unit is further adapted to:
store information indicating a desired mode of the variable valve actuation system;
generate information of a current mode of the variable valve actuation system from the generated pressure signal;
compare the information of the desired mode to the information of the current mode; and
determine an occurrence of a malfunction of the variable valve actuation system based on the comparison.

9. The system of claim 8 , wherein the control unit is further adapted to determine the occurrence of the malfunction of the variable valve actuation system as a failure to engage a low lift mode based on the pressure signal indicating the fluid pressure in the HLA chamber is below the pre-stored pressure signal.

10. The system of claim 1 , wherein the controller is further configured diagnose a first malfunction comprising a failure to engage a high lift mode operation of the variable valve actuation system, and a second malfunction comprising a failure to engage a low lift mode operation of the variable valve actuation system.

11. The system of claim 1 , wherein the control unit is further configured to diagnose the malfunction of the variable valve actuation system based on a speed of an engine operationally coupled to the variable valve actuation system being at a value selected from the values consisting of: below 3500 RPM, below 5000 RPM, and within an engine fuel economy speed range.

12. A method of diagnosing a malfunction of a variable valve actuation system, the variable valve actuation system comprising a rocker arm assembly coupled to a hydraulic lash adjuster (HLA), the method comprising the steps of:
generating a pressure signal in a fluid chamber of the HLA when the rocker arm assembly is in operation; and
determining a malfunction based upon the pressure signal, and comparing pre-stored pressure signals to the generated pressure signal to determine the malfunction.

13. The method of claim 12 wherein the rocker arm assembly comprises at least two modes.

14. The method of claim 13 wherein one of the at least two modes is a desired mode and another of the at least two modes is a current mode.

15. The method of claim 14 wherein the malfunction comprises being in a current mode that is not the desired mode.

16. The method of claim 12 wherein determining a malfunction further comprises:
comparing pre-stored pressure signals to the generated pressure signal and identifying from the comparison at least one of:
a shift of a pressure event in time;
changes in a rate of occurrence of events;
sudden unexpected pressure transients; and
an overall decrease in an amplitude of pressure events.

17. The method of claim 16 further comprising the steps of:
calculating a plurality of malfunction rates over time;
determining trends of the malfunction rates; and
estimating when the malfunction rate will reach a predetermined unacceptable malfunction rate.

18. The method of claim 12 further comprising:
determining a number of malfunctions over a predetermined period of time to calculate a malfunction rate; and
determining when the calculated malfunction rate exceeds a predetermined maximum malfunction rate.

19. The method of claim 12 , further comprising determining the malfunction as a failure to engage a high lift mode based on the pressure signal indicating the fluid pressure in the HLA is above the pre-stored pressure signal.

20. The method of claim 12 , further comprising determining the malfunction as a failure to engage a low lift mode based on the pressure signal indicating the fluid pressure in the HLA is below the pre-stored pressure signal.

21. The method of claim 12 , further comprising determining the malfunction based on a speed of an engine operationally coupled to the variable valve actuation system being below 3500 RPM.

22. The method of claim 21 , further comprising:
storing information indicating a desired mode of the variable valve actuation system;
generating information of a current mode of the variable valve actuation system from the generated pressure signal;
comparing the information of the desired mode to the information of the current mode; and
determining an occurrence of a malfunction of the variable valve actuation system based on the comparison.

23. The method of claim 22 , further comprising determining the occurrence of the malfunction of the variable valve actuation system as a failure to engage a low lift mode based on the pressure signal indicating the fluid pressure in the HLA chamber is below the pre-stored pressure signal.

24. The method of claim 23 , further comprising determining the occurrence of the malfunction of the variable valve actuation system as a failure to engage a high lift mode based on the pressure signal indicating the fluid pressure in the HLA chamber is above the pre-stored pressure si

Assignees

• Eaton Corp

Inventors

• Zurface Austin Robert
• Trudell Daniel Bennett
• Vandeusen Brian Karl

Classifications

• F01L1/2405

  by means of a hydraulic adjusting device located between the cylinder head and rocker arm · CPC title

• F01L2820/01

  Absolute values · CPC title

• F01L2001/186

  Split rocking arms, e.g. rocker arms having two articulated parts and means for varying the relative position of these parts or for selectively connecting the parts to move in unison · CPC title

• F01L2301/00

  Using particular materials · CPC title

• F01L13/0005

  Deactivating valves · CPC title