CONTROL METHOD FOR DUAL DEPENDENT VARIABLE CAM TIMING SYSTEM

摘要

PURPOSE: A control method for a dual dependent variable cam timing system is provided to improve feedback controls and to achieve the desired intake global phase and generate a desired control signal by directly controlling global phase of an exhaust VCT(Variable Camshaft Timing) phaser and local phase of an intake VCT phaser. CONSTITUTION: A variable cam timing control system of an internal combustion engine having a dual dependent camshaft configuration that an intake cam shaft is dependent upon an exhaust cam shaft is composed of an exhaust phaser(86) engaged with the exhaust cam shaft; an intake phaser(66) combined with the intake cam shaft; a first feedback loop(42) for correcting errors related to the intake phaser; and a second feedback loop(44) for correcting errors related to the exhaust phaser. The movement of the intake camshaft is dependent on the movement of the exhaust cam shaft. The first feedback loop has a measured intake phase signal(54) used to compare with a local intake set point(48) and to generate an error signal(55) used by the first feedback loop. The second feedback loop has a measured exhaust phase signal(50).