  The "dark energy" problem is investigated in the framework of the Poincare
gauge theory of gravity in 4-dimensional Riemann-Cartan space-time. By using
general expression for gravitational Lagrangian homogeneous isotropic
cosmological models with pseudoscalar torsion function are built and
investigated. It is shown that by certain restrictions on indefinite parameters
of gravitational Lagrangian the cosmological equations at asymptotics contain
effective cosmological constant and can lead to observable acceleration of
cosmological expansion. This effect has geometrical nature and is connected
with space-time torsion.
