Efficient energy recovering air inlet system for an international combustion engine

An air inlet system (10) for an internal combustion engine (200) is provided. The air inlet system comprises an air intake port (20), an air output port (30) for providing air for a combustion chamber (202) of the combustion engine (200), and a turbine (40). The turbine (40) is situated in between the air intake port (20) and the air output port (30) for turning kinetic energy of an airstream from the air intake port (20) to the air output port (30) into mechanical energy. The turbine (40) comprises at least one adjustable vane (48) for controlling an air flow resistance of the turbine (40). An electrical generator (46) is coupled to the turbine (40) for converting the mechanical energy into electrical energy. A controller (60) controls a rotational speed of the turbine (40) by controlling a quantity of electric power generated by the electrical generator (46), the controller (60) being configured to adapt the rotational speed of the turbine (40) to the air flow resistance of the turbine (40) in such a way that a substantially optimal turbine efficiency is obtained.