Back to results
US 2016/0108774 A1Published application
Method and system for variable cam timing device
AssigneeFord Global Technologies, LLC
InventorsPaul A. Pietrzyk, John Eric Rollinger, Ed Badillo
Life of this patent
Estimating the term…
Abstract
Methods and systems are described for an engine with a cam torque actuated variable cam timing phaser. Phaser positioning control is improved by reducing inaccuracies resulting from inadvertent spool valve and/or phaser movement when the spool valve is commanded between regions. In addition, improved spool valve mapping is used to render phaser commands more consistent and robust.
Claims20
A method for an engine, comprising:
- in response to a desired cam timing at a mid-lock position with a locking pin engaged, moving a spool valve to move a cam timing phaser to a position advanced of the mid-lock position;
- holding the phaser at the position advanced of the mid-lock position;
- and
- then moving the spool valve to a detent region while a cam torsional pulse occurs.
1 more element
A method for an engine, comprising:
- during a first condition, in response to a locked advance phasing command, moving a spool valve into an advance region to preposition a cam phaser at a first position advanced of a desired position, and then moving the spool valve to a detent region during a cam torsional pulse;
- and
- during a second condition, in response to a locked retard phasing command, moving the spool valve into a retard region to preposition the cam phaser at a second position, less advanced of the first position, and then moving the spool valve to the detent region during the cam torsional pulse.
A method for an engine, comprising:
- during a first operating mode, moving a cam torque actuated variable cam timing phaser to a locking position by moving a spool valve to a detent region through a retard region of the spool valve in between torsional pulses of a camshaft;
- and
- during a second operating mode, moving the phaser to the locking position by moving the spool valve to preposition the phaser advanced of the locking position, and then moving the spool valve to the detent region during the torsional pulse of the camshaft.
Dependencies are inferred from the claim text.