Control apparatus

A control apparatus for controlling a cam phase of at least one of an intake cam and an exhaust cam in an internal combustion engine relative to a crank shaft through a cam phase varying mechanism, said control apparatus comprising:

• cam phase detecting means for detecting the cam phase;
• target cam phase setting means for setting a target cam phase for the cam phase;
• control value calculating means for calculating a control value for controlling the detected cam phase to bring the same to the set target cam phase based on a predetermined control algorithm;
• and
• control input calculating means for calculating a control input to said cam phase varying means by modulating the calculated control value in accordance with an algorithm to which a predetermined modulation algorithm is applied, said control input calculating means including an amplitude setting means for setting the amplitude of the control input in accordance with an operating condition parameter representative of an operating condition of said internal combustion engine.