23-11-2017 дата публикации
Номер: US20170335726A1
Принадлежит:
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. 1. A method for an engine , comprising: 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., 'in response to a desired cam timing at a mid-lock position with a locking pin engaged,'}2. The method of claim 1 , wherein the cam torsional pulse is a retard torsional pulse.3. The method of claim 2 , wherein the cam timing phaser is a cam torque actuated variable cam timing phaser.4. The method of claim 3 , wherein moving the spool valve to move the phaser to a position advanced of the mid-lock position includes when current cam timing is retarded of the mid-lock position claim 3 , moving the spool valve to an advance region of the spool valve to move the phaser to a first position advanced of the mid-lock position.5. The method of claim 4 , wherein the phaser is held at the first position advanced of the mid-lock position with the locking pin disengaged claim 4 , the method further comprising claim 4 , after the cam torsional pulse has occurred claim 4 , engaging the locking pin.6. The method of claim 5 , wherein moving the spool valve to move the phaser to a position advanced of the mid-lock position further includes claim 5 , when the current cam timing is advanced of the mid-lock position claim 5 , moving the spool valve of the cam timing phaser to move the phaser to a second position advanced of the mid-lock position claim 5 , the second position less advanced relative to the first ...
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