Actuator motion control

Patent metadata

Field	Value
Publication number	US-9777686-B2
Application number	US-201514660015-A
Country	US
Kind code	B2
Filing date	Mar 17, 2015
Priority date	Mar 20, 2014
Publication date	Oct 3, 2017
Grant date	Oct 3, 2017

Abstract

A system for controlling actuation of an electromagnetic actuator includes an actuator having an electrical coil, a magnetic core, and an armature. A controllable drive circuit is responsive to an electric power flow signal for driving current through the electrical coil to actuate the armature. A control module includes an armature motion observer configured to determine an armature motion parameter in the actuator based upon a magnetic flux within the actuator and a predetermined mechanical equation of motion corresponding to the actuator and adapt the electric power flow signal based on the armature motion parameter.

First claim

The invention claimed is:

1. A method for controlling an electromagnetic actuator including an electrical coil, a magnetic core, and an armature comprising a position dependent mass adjacent the magnetic core, comprising:
determining a magnetic flux within the actuator when the electrical coil is energized by a current;
determining a magnetic force acting upon the armature based upon the magnetic flux, a surface area of the armature near an air gap between the magnetic core and armature, and armature position;
applying the magnetic force as a forcing function upon a mechanical equation of motion corresponding to the actuator to determine at least one armature motion parameter; and
controlling the actuator based upon said at least one armature motion parameter.

2. The method for controlling the electromagnetic actuator of claim 1 , wherein determining the magnetic flux within the actuator, comprises determining the magnetic flux based upon a search coil voltage.

3. The method for controlling the electromagnetic actuator of claim 1 , wherein determining the magnetic flux within the actuator, comprises determining the magnetic flux based upon an electrical coil voltage.

4. The method for controlling the electromagnetic actuator of claim 1 , wherein determining the magnetic flux within the actuator, comprises determining the magnetic flux based upon a magnetic field sensor signal.

5. The method for controlling the electromagnetic actuator of claim 1 , wherein determining the magnetic force acting upon the armature comprises determining the magnetic force in accordance with the following relationship:

f
mag

≅

s
a

·

(

B
n

·

b
⁡

(

s
,
φ

)

)

2

2
⁢

μ
o

wherein ƒ mag is the magnetic force,
S a is the surface area of the armature near the air gap,
B n is the flux density

(

φ

s
a

)

 of the armature near the air gap,
μ o is the permeability of free space, and
b is a correction factor that is a function of armature position s and flux φ.

6. The method for controlling the electromagnetic actuator of claim 1 , wherein the mechanical equation of motion is represented by the following relationship:

f
mag

=

m
⁢

d
2

⁢
s

dt
2

+
f

wherein ƒ mag is the magnetic force acting upon the armature,
m is a moving mass of the armature,
s is armature position, and
ƒis an aggregate force acting upon the armature.

7. The method for controlling the electromagnetic actuator of claim 1 , wherein said at least one armature motion parameter comprises position.

8. The method for controlling the electromagnetic actuator of claim 1 , wherein controlling the actuator based upon said at least one armature motion parameter comprises providing said at least one armature motion parameter in feedback in an armature position control module.

9. The method for controlling the electromagnetic actuator of claim 8 , wherein said armature position control module comprises an armature motion observer.

10. A system for controlling actuation of a fuel injector, comprising:
a fuel injector comprising an electrical coil, a magnetic core, and an armature comprising position dependent mass comprising a moving mass of a first portion of the armature and a moving mass of a second portion of the armature;
a controllable drive circuit responsive to a power flow signal for driving current through the electrical coil to actuate the armature; and
a control module configured to determine an armature motion parameter in the fuel injector and adapt the power flow signal based on the armature motion parameter.

11. The system for controlling actuation of the fuel injector of claim 10 , wherein said control module comprises an armature motion observer configured to determine said armature motion parameter based upon a magnetic flux within the fuel injector.

12. The system for controlling actuation of the fuel injector of claim 11 , further comprising a search coil mutually magnetically coupled to the electrical coil, said control module further configured to determine said magnetic flux within the fuel injector based on the search coil.

13. The system for controlling actuation of the fuel injector of claim 11 , further comprising a magnetoresistive sensor disposed within a flux path within the fuel injector, said control module further configured to determine said magnetic flux within the fuel injector based on the magnetoresistive sensor.

14. The system for controlling actuation of the fuel injector of claim 11 , further comprising a hall effect sensor disposed within a flux path within the fuel injector, said control module further configured to determine said magnetic flux within the fuel injector based on the hall effect sensor.

15. The system for controlling actuation of the fuel injector of claim 11 , wherein said armature motion observer:
determines a magnetic flux within the actuator when the electrical coil is energized by a current;
determines a magnetic force acting upon the armature based upon the magnetic flux, a surface area of the armature near an air gap between the magnetic core and armature, and armature position; and
applies the magnetic force as a forcing function upon a mechanical equation of motion corresponding to the actuator to determine said armature motion parameter.

16. The system for controlling actuation of the fuel injector of claim 15 , wherein the magnetic force acting upon the armature is determined in accordance with the following relationship:

Assignees

• Gm Globaltechnology Operations Llc
• Gm Global Tech Operations Llc

Inventors

• Nehl Thomas Wolfgang
• Gopalakrishnan Suresh
• Omekanda Avoki M
• Namuduri Chandra S

Classifications

• F02M51/061

  using electromagnetic operating means · CPC title

• F02M51/0625 Primary

  characterised by arrangement of mobile armatures · CPC title

• F02D2041/2051

  using voltage control · CPC title

• F02D41/14

  Introducing closed-loop corrections · CPC title

• F02M51/0671 Primary

  the armature having an elongated valve body attached thereto · CPC title