Patent ID: 8091523

Claim:
An apparatus of controlling a variable valve timing mechanism that varies valve timing of an engine valve, comprising: a target calculation unit that calculates target valve timing; a first calculation unit that calculates a first manipulated variable based on the target valve timing; a second calculation unit that calculates a second manipulated variable by which a variation speed of valve timing is maximized; an estimation unit that estimates valve timing of when the second manipulated variable is output to the variable valve timing mechanism; a determination unit that determines timing at which the second manipulated variable is switched to the first manipulated variable based on a comparison of an estimated valve timing with the target valve timing; and an operation unit that outputs the second manipulated variable to the variable valve timing mechanism in a period after a start of an engine and before it is determined to be the switching timing, and outputs the first manipulated variable to the variable valve timing mechanism in a period after it is determined to be the switching timing.