CONTROL METHOD FOR ACHIEVING EXPECTED VCT ACTUATION RATE BY USING SET POINT RATE LIMITER

摘要

PURPOSE: A control method for achieving the expected VCT(Variable Camshaft Timing) actuation rate by using a set point rate limiter is provided to reduce loop errors and to decrease overshoot caused by the change of a set value. CONSTITUTION: A VCT system have a feedback loop for controlling a phaser angular relationship and a controller having a control law(18a) disposed to receive a plurality of set point values(12) and a plurality of feed back values(16). The control law comprises a computation block(40) for receiving a plurality of the set point values as inputs and outputting first and second outputs; a first summer for summing the first output and a plurality of the feed back values to produce a first sum(e0); a phase integrator(42) and a phase compensator(44) for receiving the first sum and derivatives(e1) and outputting a processed value(e2); an amplifier for amplifying the second output by a predetermined scale(Kff); and a second summer for summing the processed value and the amplified second output to produce a second sum(e3).