  Investigations of the dynamic modes of the Poincare gauge theory of gravity
found only two good propagating torsion modes; they are effectively a scalar
and a pseudoscalar. Cosmology affords a natural situation where one might see
observational effects of these modes. Here we consider only the ``scalar
torsion'' mode. This mode has certain distinctive and interesting qualities. In
particular this type of torsion does not interact directly with any known
matter and it allows a critical non-zero value for the affine scalar curvature.
Via numerical evolution of the coupled nonlinear equations we show that this
mode can contribute an oscillating aspect to the expansion rate of the
Universe. From the examination of specific cases of the parameters and initial
conditions we show that for suitable ranges of the parameters the dynamic
``scalar torsion'' model can display features similar to those of the presently
observed accelerating universe.
