Patent ID: 6722328
Filing Date: 2004-04-20
Classification: F01L

Abstract:
A variable cam timing (VCT) control system used in an internal combustion engine, said system having a dual dependent cam shaft configuration, wherein an intake cam shaft is dependent upon an exhaust cam shaft, comprising:a) an exhaust phaser engaging said exhaust cam shaft; b) an intake phaser engaging said intake cam shaft, the movement of said intake cam shaft being dependent upon the movement of said exhaust cam shaft; c) a first feedback loop for correcting errors relating to said intake phaser, said first feedback loop including a measured intake phase signal, being used to compare with a local intake set point and being used to generate an error signal used by the first feedback loop; and d) a second feedback loop for correcting errors relating to said exhaust phaser, said second feedback loop including a measured exhaust phase signal, wherein said measured exhaust phaser signal is used for adjustments of both said exhaust phaser and said intake phaser.