Control unit and method for monitoring the function of an electromagnetic actuator

Patent metadata

Field	Value
Publication number	US-10643775-B2
Application number	US-201615761976-A
Country	US
Kind code	B2
Filing date	Sep 15, 2016
Priority date	Sep 21, 2015
Publication date	May 5, 2020
Grant date	May 5, 2020

Abstract

A magnetic core and an electric coil, wherein the magnetic core is configured to move by supplying current to the electric coil to allow electrical energy to be transformed into mechanical energy and an electromagnetic actuator operates a valve body to move, and a controller configured to measure a current flowing through the electric coil, select a temporal evaluation section of a course of the current, wherein the current changes from a current value at a beginning of the temporal section to a current value at an end of the section, wherein the evaluation section lasts for a duration period, form an evaluation product from at least the current value at the beginning of the section, the current value at the end of the section, and the duration period of the section, and detect an error function of the actuator by comparing the evaluation product with an evaluation product limit.

First claim

The invention claimed is:

1. A method for monitoring the function of an electromagnetic actuator, comprising:
shifting a magnetic core within the electromagnetic actuator by supplying a current to an electric coil, wherein the magnetic core shifts between a first spring and a second spring, wherein a first surface of the magnetic core is in contact with the first spring and a second surface of the magnetic core is in contact with the second spring;
measuring of a temporally varying current flowing through the electric coil;
selecting of a temporal evaluation section of a course of the temporally varying current, wherein the temporally varying current changes from a current value at a beginning of the temporal section to a current value at an end of the section, wherein the temporal evaluation section lasts for a duration period;
forming of an evaluation product from factors which comprise at least the current value at the beginning of the section and the current value at the end of the section as well as the duration period of the section; and
detecting of an error function of the actuator by comparing the evaluation product with an evaluation product limit;
wherein the evaluation product represents a surface area of an area at a graph of a function of the temporally varying current, wherein the area is limited at least by one point of the graph of the function that is assigned to the current value of the beginning of the section and by one point of the graph of the function that is assigned to the current value of the end of the section;
wherein the area is limited by a first line that runs through the point of the graph of the function that is assigned to the current value of the beginning of the section; and that the area is limited by a second line that runs through the point of the graph of the function that is assigned to the current value of the end of the section;
wherein the area is furthermore limited by a portion of the graph of the function that is assigned to the evaluation section; and
wherein a portion of the graph of the function that is assigned to the evaluation section is approximated by a third line in a first evaluation partial section; and that the portion of the graph of the function that is assigned to the evaluation section is approximated by a fourth line in a second evaluation partial section; wherein the area is formed by a tetragon, which sides are made up by the first line, by the second line, by the third line and by the fourth line.

2. The method of claim 1 , wherein the current that is flowing through the electric coil rises during a current increase phase, while along its course, the magnetic core is initially in an idle mode; wherein the current increase phase is followed by a current peak phase, in which the current decreases from a current peak phase start value to a current peak phase intermediate value and then rises from a current peak phase intermediate value to a current peak phase end value; wherein the current peak phase is followed by a holding current phase, in which the current decreases until it reaches a range of a holding current value and remains there; and wherein the holding current phase is followed by a phase-out period, in which the current rises from a phase-out period beginning current value to a phase-out period intermediate current value and then sinks from the phase-out period intermediate current value to a phase-out period end current value.

3. The method of claim 2 , wherein the evaluation section is located within the current increase phase; wherein the current value at the end of the section is smaller than the maximum current value and is temporally situated prior to the end of the current increase phase; and wherein the current value at the beginning of the section is provided at a deviation point, which is determined by the following partial steps:
creating a logarithmic function of the current that was measured in the current increase phase;
approximating of the logarithmic function, which represents an early temporal partial section of the idle mode, by a linear function;
a constant determining of a difference between the logarithmic function and the linear function beyond the early temporal partial section of the idle mode; and
determining the deviation point based on the point, in which the difference reaches a pre-defined difference value.

4. The method of claim 3 , wherein the evaluation section is located within the current peak phase, wherein the current value at the end of the section is larger than the intermediate value within the current peak phase and is reached prior to the intermediate value within the current peak phase.

5. The method of claim 4 , wherein the evaluation section is located within the phase-out period, wherein a phase-out period start value is used as the current value at the beginning of the section, and wherein the current value at the end of the section is smaller than the phase-out period intermediate value and is reached temporally before the phase-out period intermediate value.

6. A method for monitoring a function of an electromagnetic actuator, comprising:
measuring of a current flowing through an electric coil wrapped around a magnetic core of the electromagnetic actuator, wherein the magnetic core shifts between a first spring and a second spring, wherein a first surface of the magnetic core is in contact with the first spring and a second surface of the magnetic core is in contact with a valve body;
selecting of a temporal evaluation section of a course of the current, wherein the current changes from a current value at a beginning of the temporal section to a current value at an end of the section, wherein the temporal evaluation section lasts for a duration period;
forming of an evaluation product from at least the current value at the beginning of the section, the current value at the end of the section, and the duration period of the section; and
detecting an error function of the actuator by comparing the evaluation product with an evaluation product limit.

7. The method of claim 6 , wherein the error function is detected when there is a blockage of the electromagnetic actuator.

8. The method of claim 6 , wherein the method further includes outputting to the error function to regulate a combustion engine.

9. The method of claim 6 , wherein the evaluation product includes a voltage value of an operating voltage applied to the electric coil for supplying current to the electric coil.

10. The method of claim 6 , wherein the evaluation product represents a surface area of an area at a graph of a function of the current that has changed within the duration period.

11. The method of claim 10 , wherein the area is limited at least by one point of the graph of the function that is assigned to the current value at the beginning of the section and by one point of the graph of the function that is assigned to the current value at the end of the section.

12. A control valve, comprising:
a magnetic core and an electric coil, wherein the magnetic core is configured to be moved by supplying a current to the electric coil to allow electric energy to be transformed into mechanical energy and an electromagnetic actuator operates a valve body that is to be moved, wherein the magnetic core is located between a first spring and a second spring, and a first surface of the magnetic core is in contact with the first spring and a second surface of the magnetic core is contact with the valve body; and
a controller configured to:
measure a current flowing through the electric coil;
select a temporal evaluation section of a course of the current, wherein the current changes from a

Assignees

• Schaeffler Technologies Ag

Inventors

• Wang Weigang
• Traversa Piergiacomo
• Elicker Michael

Classifications

• H01F7/1844 Primary

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

• G01R31/3278

  of relays, solenoids or reed switches (measuring contact resistance G01R27/205; high voltage magnetic switches G01R31/3271, G01R31/333; testing electric windings G01R31/72; monitoring of fail safe circuits H01H47/002) · CPC title

• F16K37/0083

  by measuring valve parameters · CPC title

• H01F2007/1861

  using derivative of measured variable · CPC title

• F16K31/0675

  Electromagnet aspects, e.g. electric supply therefor · CPC title