  In five dimensional cosmological models, the convention is to include the
fifth dimension in a way similar to the other space dimensions. In this work we
attempt to introduce the fifth dimension in a way that a time dimension would
be introduced. With such an internal space, we are able to obtain accelerated
expansion without introducing dark energy. We obtain a five dimensional flat,
meaning both Ricci flat and conformally flat, spacetime into which all relevant
four dimensional cosmologies can be locally embedded. We also argue on the
choice of the cosmological frame. The choice that is simplest and most
convenient in terms of dimensional analysis, amounts to a linearly expanding
universe.
