  We apply methods of dynamical systems to study the behaviour of universe
dominated by the generalized Chaplygin gas. We reduce the dynamics to a
2-dimensional Hamiltonian system and study its behaviour for various ranges of
parameters. The dynamics is studied on the phase plane by using methods of
qualitative analysis of differential equations. The behaviour of trajectories
at infinity is studied in some convenient coordinates introduced on the phase
plane. Hence we shown that FRW model with the generalized Chaplygin gas is
structurally stable. We clearly find the domains of cosmic acceleration as well
as conditions for which the horizon problem is solved. We also define some
general class of fluids which generalize the Chaplygin gas. The dynamics of
such models in terms of energy conditions is also discussed.
