A variable valve timing control device includes a rotational shaft, a rotation transmitting member assembled around the rotational shaft, and a vane assembled to one of the rotational shaft and the rotation transmitting member. The variable valve timing control device also includes a fluid pressure chamber defined between the rotational shaft and the rotation transmitting member and divided into a retarded angle chamber and an advanced angle chamber by the vane, a fluid passage through which an operation fluid is selectively supplied to or discharged from the advanced angle chamber or the retarded angle chamber, and a torsion coil spring for constantly biasing the rotational shaft to an advanced angle direction relative to the rotation transmitting member. The torsion coil spring is disposed between the rotational shaft and the rotation transmitting member under a condition that the torsion spring is compressed to a predetermined length from a free length.

 
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> Method to control electromechanical valves in a DISI engine

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