Back to results
US 2016/0108775 A1Published application
Method and system for variable cam timing device
AssigneeFord Global Technologies, LLC
InventorsPaul A. Pietrzyk, John Eric Rollinger, Gilbert Fournelle
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:
- moving a spool valve to move a cam torque actuated variable cam timing phaser to a locking position;
- holding the phaser at the locking position without engaging a locking pin for a duration;
- and
- after the duration, further moving the spool valve to engage the locking pin.
1 more element
A method for an engine, comprising:
- during a first condition, moving a cam timing phaser to a locking position without prepositioning and holding the phaser in the locking position without engaging a locking pin;
- and
- during a second condition, moving the phaser to the locking position with prepositioning and holding the phaser in the locking position with the locking pin engaged.
An engine system, comprising:
- an engine cylinder including valves;
- 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, the phaser including a locking circuit with a locking pin;
- a solenoid driven spool valve for adjusting a position of the phaser;
- and
- a controller with computer readable instructions stored on non-transitory memory for:
- receiving a command for moving the phaser to a desired position;
- in response to the command, moving the spool valve to use cam torque actuated hydraulic pressure separate from engine generated oil pressure to move the phaser to the desired position;
- holding the phaser in the desired position with the locking pin disengaged for a duration, the locking pin held disengaged via the engine generated oil pressure applied on the locking circuit;
- and
- in response to one of engine generated oil pressure being lower than a threshold pressure and oil temperature being lower than a threshold temperature during the holding,
- moving the spool valve to a detent region to reduce engine generated oil pressure applied on the locking circuit and engage the locking pin.
9 more elements
Dependencies are inferred from the claim text.