A reciprocating engine includes a turbocharging unit that: supplies the intake manifold with air via a coolant; is supplied with gas by the exhaust manifold; and has the turbine supply pressure substantially equal to the compressor discharge pressure. At constant air temperature, the turbocharging unit delivers a substantially constant volume of cooled air when the pressure varies, and the volume is substantially proportional to the turbine outlet section. The turbine pressure is maintained substantially equal to compressor pressure by a EGR bypass between the intake and exhaust manifold. In addition, the volume of air is less than the volume drawn in at the speed so that a flow of hot gases is drawn in again via the bypass above the speed, where the volume drawn in is equal to the volume, and a flow of air is deflected towards the turbine below the speed.