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US 10,520,334 B2Granted
Induction based position sensing in an electromagnetic actuator
AssigneeDana Automotive Systems Group, LLC
InventorsMichael Z. Creech, Justin S. Davis
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Abstract
The present invention relates to a method and system for determining the position of the armature of a solenoid using a controller to determine the temperature of the solenoid and to indirectly determine the position of the armature without the need of an additional sensor using current sensing pulses and a solenoid capable of staying engaged due to residual magnetism after the coil has been de-energized.
Claims12
A method for sensing a position of an armature in a solenoid, said method comprising:
- providing a solenoid having a coil, a housing and an armature;
- applying a current to the coil to move the armature into a variety of positions including engaged and disengaged;
- terminating the current used to move the armature;
- applying a resistance-sensing voltage pulse to the coil, wherein the resistance-sensing voltage pulse is insufficient to move the armature;
- measuring the ohmic resistance from the resistance-sensing voltage pulse;
- determining the temperature of the coil from the measured ohmic resistance;
- applying an inductance-sensing voltage pulse to the coil, wherein the inductance-sensing voltage pulse is insufficient to move the armature;
- measuring the current rise or fall from the inductance-sensing voltage pulse;
- and
- comparing the measured current rise or fall to a pre-determined value, wherein the pre-determined value is either (i) a current rise or fall of the solenoid when the armature is in engagement at the determined temperature or (ii) a current rise or fall of the solenoid when the armature is in non-engagement with the solenoid at the determined temperature to determine the position of the armature relative to the solenoid.
7 more elements
A system for determining a position of an armature in a solenoid, the system comprising:
- a solenoid including a coil, an armature and a housing, wherein the coil is at least partially enclosed in the housing and the armature is selectively in a coupled or uncoupled position relative to the housing;
- a controller in communication with the solenoid to provide the coil with magnetization current and to detect current, rise time and ohmic resistance in the coil;
- and
- wherein the armature and housing are constructed of ferromagnetic material capable of holding a residual magnetic force.
1 more element
Dependencies are inferred from the claim text.