Turbocompound internal combustion engine

A turbocompound internal combustion engine (1) having a turbocharger (2) with a variable-geometry turbine (3); and an auxiliary turbine (13), which is located downstream from the turbine (3) of the turbocharger (2), provides for recovering energy from the exhaust gas, and is connected mechanically to the drive shaft (19) of the engine via a transmission (20); a control device (31) compares the rotation speed of the auxiliary turbine (13), detected by means of a sensor (28), with a range of permissible speeds calculated on the basis of the speed of the drive shaft (19), and controls fuel supply to the engine (1) and the geometry of the variable-geometry turbine (3) to maintain the speed of the auxiliary turbine (13) within predetermined limits in the event of a fault on the transmission (20).