The notion of
dynamical entropy for actions of a countable free abelian group $G$ by
automorphisms of $C^*$-algebras is studied. These results are applied to
Bogoliubov actions of $G$ on the CAR-algebra. It is shown that the dynamical
entropy of Bogoliubov actions is computed by a formula analogous to that
found by Størmer and Voiculescu in the case $G={\bf Z}$, and also it is
proved that the part of the action corresponding to a singular spectrum gives
zero
contribution to the entropy. The case of an infinite number of generators has
some essential differences and requires new arguments.