Abstract: An air intake device for an engine comprises an intake manifold (1) equipped with a series of intake pipes (4) respectively associated with an inlet duct (5) of the cylinder head (3), each of the inlet ducts being subdivided into an upper duct segment (50) and a lower duct segment (51) by a partition (6), and the intake manifold (1) being equipped with a series of flaps (7) mounted about a common rotation shaft (8). The partition (6) of each of the inlet ducts (5) extends into the associated intake pipe (4), and each of the flaps (7) is rotatably moveable between an open position and a sealing position in which each flap (7) essentially seals the lower segment (51) of the associated inlet duct (5).