The invention concerns a turbo compound system, including a crankshaft driven by an internal combustion engine; a blowdown turbine arranged in the exhaust line of the internal combustion engine; a hydrodynamic clutch, including a driving torus and a driven torus, which form with each other a working chamber that is fillable or filled with working fluid; where the driven torus of the hydrodynamic clutch is arranged on a shaft on the crankshaft side, which is in drive connection with the crankshaft and is geared up relative to the crankshaft; and where the driving torus of the hydrodynamic clutch is arranged on a shaft on the blowdown turbine side, which is in drive connection with the blowdown turbine, and where a rotary pump is arranged on the shaft on the crankshaft side or on the shaft on the blowdown turbine side, whose impeller is driven by this shaft.