  We summarize recent results concerning the evolution of second order
perturbations in flat dust irrotational FLRW models with $\Lambda\ne 0$. We
show that asymptotically these perturbations tend to constants in time, in
agreement with the cosmic no-hair conjecture. We solve numerically the second
order scalar perturbation equation, and very briefly discuss its all time
behaviour and some possible implications for the structure formation.
