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 for an engine, comprising:
indicating degradation of a variable cam timing phaser based on cam torque oscillations being higher than a threshold, the cam torque oscillations learned during a condition while a spool valve of the variable cam timing phaser is outside a no-fly zone.