Abstract: An intake duct 1 is provided, particularly for taking air in an internal combustion engine, notably the engine of an automobile. The duct includes a first wall 2 made of a porous material, wherein a film 4 is implemented which is sufficiently thin for avoiding any incidence upon the acoustical characteristics, having notably a surface mass of less than 100 grams per square meter. The film 4 is fixed onto the porous wall 2 such that at least 50% of the surface of the film facing the porous wall 2 is not fixed thereto.

Abstract: An intake duct 1 is provided, particularly for taking air in an internal combustion engine, notably the engine of an automobile. Said duct includes a first wall 2 made of a porous material, wherein a film 4 is implemented which is sufficiently thin for avoiding any incidence upon the acoustical characteristics, having notably a surface mass of less than 100 grams per square meter. Said film 4 is fixed onto said porous wall 2 such that at least 50% of the surface of said film facing said porous wall 2 is not fixed thereto.

Abstract: Thermoformed intake duct (1) made of non-woven material and including flanges (6, 7, 8, 9) parallel to the longitudinal axis of the duct, projecting from the outer surface of the duct, a first portion (4) of the duct being formed in the form of a first bellows, a first bellows-shaped portion (4) having two longitudinal flanges (6, 7) diametrically opposed along a first diameter (D2), characterized in that the duct includes at least a second bellows-shaped portion (5) having two longitudinal flanges (8, 9) diametrically opposed along a second diameter (D3) of the duct which makes, with respect to the first diameter (D2) of the two flanges (6, 7) of the first bellows-shaped portion, a non-zero angle, and especially 90°.

Abstract: Air filter (F), especially for an internal combustion engine motor vehicle, comprising a duct (1) for coupling to an intake duct (5), a female portion (3) of the connecting duct being intended to cover a male portion of the intake duct, characterized in that the female portion (3) has two parallel longitudinal openings (7), the two openings (7) being preferably diametrically opposed, and the female portion (3) includes an end-piece in the form of a frustoconical chamfer (4), so that the female portion (3) is of greater size in cross section than the remainder (2) of the coupling duct (1), and means, preferably removable means, are provided for fastening the filter to the intake duct (5).