Added acceleration system for endothermic engine

Added acceleration system (S) for an endothermic engine (1), comprising means (4,7,11,12,13) for an additional air intake to at least one cylinder of said engine (1), the mentioned intake system comprising means (4,7,11) for withdrawing said compressed air from means (6) for containing compressed air coupled and being integral part of said cylinder, and intake means (12,13) suitable for introducing said compressed air directly in an intake pipe (14) of said cylinder before the fuel injection.