METHOD AND SYSTEM FOR VARIABLE CAM TIMING DEVICE

摘要

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.

主权项

1. A method, comprising:
during selected conditions, ramping a spool valve coupled to a cam torque actuated variable cam timing phaser from a detent region to a retard region; and mapping a transitional region between the detent and retard regions based on phaser movement away from a locked position, the phaser movement responsive to the ramping.