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US 2016/0108773 A1Published application
Method and system for variable cam timing device
AssigneeFord Global Technologies, LLC
InventorsJohn Eric Rollinger, Paul A. Pietrzyk, Edward Badillo
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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, comprising:
- moving a spool valve of a cam torque-actuated variable cam timing phaser to a detent region in between torsional pulses of a camshaft.
A method, comprising:
- moving a cam torque actuated variable cam timing phaser from advanced of a locking position to the locking position by moving a spool valve through a retard region of the spool valve in between torsional pulses of a camshaft.
An engine system, comprising:
- an engine cylinder including valves and a crankshaft;
- cams coupled to a camshaft for actuating the valves;
- a variable cam timing phaser for adjusting valve timing, the phaser actuated using torque from the cams;
- a spool valve for adjusting a position of the phaser, and
- a controller with computer readable instructions stored on non-transitory memory for:
- estimating a timing of retard torsional pulses of the camshaft based on camshaft position relative to crankshaft position;
- advancing the phaser to a locking position and holding the phaser in the locking position without engaging a locking pin by moving the spool valve in between the torsional pulses while holding the spool valve during the torsional pulses;
- and
- after advancing the phaser to the locking position, engaging the locking pin.
6 more elements
Dependencies are inferred from the claim text.