Back to results
US 2016/0108767 A1Published application
Method and system for variable cam timing device
AssigneeFord Global Technologies, LLC
InventorsPaul A. Pietrzyk, Ed Badillo, John Eric Rollinger
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, comprising:
- in response to a command for phasing a cam torque actuated variable cam timing phaser from a locked position,
- jumping a spool valve from a detent region to outside a null region;
- and
- ramping the spool valve through the null region while monitoring for cam timing movement away from a locked position.
1 more element
A method for a cam torque actuated variable cam timing phaser, comprising:
- in response to an unlocking advance phasing command, jumping a spool valve from a detent region to a retard region outside a null region before ramping the spool valve through the null region towards an advance region;
- and
- in response to an unlocking retard phasing command jumping a spool valve from the detent region to the advance region outside the null region before ramping the spool valve through the null region towards the retard region.
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;
- 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 out of a locked position to a desired unlocked position;
- and
- in response to the command,
- adjusting a duty cycle applied to the solenoid to jump the spool valve from a detent region to a position immediately outside a null region, the position selected based on a commanded direction of moving the phaser;
- and
- then, ramping the spool valve through the null region while monitoring phaser motion out of the locked position, a direction of the ramping also based on the commanded direction of moving the phaser.
9 more elements
Dependencies are inferred from the claim text.