  The motion of a Brownian particle in the presence of Coulomb friction and an
asymmetric spatial potential was evaluated in this study. The system exhibits a
ratchet effect, i.e., an average directed motion even in the absence of an
external force, induced by the coupling of non-equilibrium conditions with the
spatial asymmetry. Both the average motion and the fluctuations of the Brownian
particle were analysed. The stationary velocity shows a non-monotonic behaviour
as a function of both the temperature and the viscosity of the bath. The
diffusion properties of the particle, which show several time regimes, were
also investigated. To highlight the role of non-linear friction in the
dynamics, a comparison is presented with a linear model of a Brownian particle
driven by a constant external force, which allows for analytical treatment. In
particular, the study unveils that the passage times between different temporal
regimes are strongly affected by the presence of Coulomb friction.
