Air intake system containing an opening provided with a notch to confer a swirling movement on intake gases

The system a valve (36) with its extreme degree of opening controlled according to operating parameters of a combustion engine. The circumference (46) of an inlet orifice (32) associated to the valve has a notched angular sector (66) which extends on an arc along a direction tangential to turbulent gas flow in a combustion chamber of the engine such that inlet gas flow is oriented tangential to the turbulent gas flow.