A control device and method for adjusting the angular velocity ratio (N(t)/K(t))
between a camshaft and a crankshaft is provided. Various control devices and methods
for rotating the camshaft relative to the crankshaft provide a drive which may
advance and retard the camshaft in comparison to the crankshaft. Previous systems
have the disadvantage that either two drives in different directions are necessary
for each actuation direction or the drive must have right-handed rotation and left-handed
rotation. In the control device and the method according to the invention, the
advancing of the camshaft is achieved by a drive in the running direction of the
camshaft and the retarding is achieved by a braking device. It has been shown to
be especially advantageous if an electric motor in two quadrant mode is used as
the drive, which may then also be used as the braking device. Such a control device
and method are required for setting the control times in internal combustion engines.