Land vehicle with an engine comprising an air intake duct provided with a device for selectively generating an air tumble in the combustion chamber

A road vehicle (1) having an endothermic engine (2) comprising an air intake duct (3) for introducing air into at least one combustion chamber (4);

• wherein in the air intake duct (2) a device (5) is provided for selectively generating a tumble of air in the combustion chamber (4);
• characterized in that the device (5) for selectively generating a tumble consists of a single fin (6) arranged within the air intake duct (3);
• in which the fin (6) is shaped as a corresponding portion of the inner surface of the intake duct (3) and is movable between a rest position, in which it is substantially entirely in contact with the corresponding portion of the inner surface of the intake duct (3) and does not interfere with the flow of air passing through the intake duct (3), and a plurality of working positions in which it progressively penetrates the intake duct (3) to convey the flow of air passing through only at a portion of the intake duct (3).