Intake device for internal combustion engine with spark ignition

The arrangement has for each cylinder, a flexible vane (5) fixed between an injector (4) and a valve (3). The vane is integrated to intake duct wall over length (L) of the duct from the valve, and is free from the wall over remaining length. The free portion of the vane moves between a rest position in which it diametrically separates the duct into two identical portions and a position in which one duct portion is closed by the vane.