Method and apparatus for monitoring an electromagnetic hydraulic valve for a variable valve timing system

Patent metadata

Field	Value
Publication number	US-9207146-B2
Application number	US-201414458260-A
Country	US
Kind code	B2
Filing date	Aug 13, 2014
Priority date	Aug 20, 2013
Publication date	Dec 8, 2015
Grant date	Dec 8, 2015

Abstract

A method monitors an electromagnetic hydraulic valve for controlling a hydraulically adjustable valve gear of a reciprocating piston engine. The hydraulic valve includes an electromagnetic coil and a moving armature configured to connect a control port hydraulically to a high-pressure port or a low-pressure port, depending on an energization of the coil. The method includes detecting a movement of the armature, using a control unit, in response to an energization of the coil based on a mutual induction in the coil and identifying a defect, using the control unit, if the expected mutual induction does not occur.

First claim

The invention claimed is:

1. A method for monitoring an electromagnetic hydraulic valve for controlling a hydraulically adjustable valve gear of a reciprocating piston engine, the hydraulic valve including an electromagnetic coil and a moving armature configured to connect a control port hydraulically to a high-pressure port or a low-pressure port, depending on an energization of the coil, the method comprising:
detecting a movement of the armature, using a control unit, in response to another energization of the coil resulting from a mutual induction in the coil; caused by movement of the armature; and
identifying a defect, using the control unit, if the expected mutual induction does not occur.

2. The method as recited in claim 1 , further comprising:
switching on a current through the coil;
sampling a voltage or a current on the coil;
detecting that there is no temporary dip in the voltage or the current after switching on, and
detecting the defect.

3. The method as recited in claim 2 , further comprising detecting that the temporary dip does not occur in a predetermined time window after switching on.

4. The method as recited in claim 3 , wherein a start of the time window is chosen in such a way that it lies before an expected beginning of movement of the armature.

5. The method as recited in claim 3 , wherein an end of the time window is chosen in such a way that it lies before an expected end of movement of the armature.

6. The method as recited in claim 4 , wherein an end of the time window is chosen in such a way that it lies before an expected end of movement of the armature.

7. The method as recited in claim 1 , storing a fault code in a non-volatile memory when the defect has been detected.

8. The method as recited in claim 2 , storing a fault code in a non-volatile memory when the defect has been detected.

9. The method as recited in claim 3 , storing a fault code in a non-volatile memory when the defect has been detected.

10. The method as recited in claim 4 , storing a fault code in a non-volatile memory when the defect has been detected.

11. The method as recited in claim 5 , storing a fault code in a non-volatile memory when the defect has been detected.

12. The method as recited in claim 6 , storing a fault code in a non-volatile memory when the defect has been detected.

13. A control unit for monitoring an electromagnetic hydraulic valve for controlling a hydraulically adjustable valve gear of a reciprocating piston engine, the hydraulic valve including an electromagnetic coil and a moving armature configured to connect a control port hydraulically to a high-pressure port or a low-pressure port, depending on an energization of the coil, the control unit being configured:
to detect a movement of the armature in response to another energization of the coil resulting from a mutual induction in the coil; caused by movement of the armature; and
to identify a defect if the expected mutual induction does not occur.

Assignees

• Porsche Ag

Inventors

• Melzig Thomas
• Pelters Stephan
• Wunderlich Arno
• Kretzschmar Lutz

Classifications

• H01F7/1844 Primary

  Monitoring or fail-safe circuits (for relays H01H47/002) · CPC title

• F01L2820/031

  Electromagnets · CPC title

• F01L13/0036

  the valves being driven by two or more cams with different shape, size or timing or a single cam profiled in axial and radial direction · CPC title

• F01L2800/11

  Fault detection, diagnosis · CPC title

• G01M15/042 Primary

  by monitoring a single specific parameter not covered by groups G01M15/06 - G01M15/12 · CPC title