In this paper we consider a new version of Chaplygin gas cosmology that includes bulk viscosity and a varying gravitational constant. This new model of Chaplygin gas allows us to recover a barotropic fluid with a quadratic equation of state. Bulk viscosity is assumed to be a power law function of the energy density. We study the evolution of dark energy density numerically for several forms of scale factor and analytically under some assumptions corresponding to a late epoch of the universe. We discuss some cosmological parameters and fix them using recent observational data, such as those from the Background Imaging of Cosmic Extragalactic Polarization 2 (BICEP2) telescope.
