Internal combustion engine with exhaust gas turbocharger and compound power turbine

An internal combustion engine having a crankshaft and including an exhaust gas turbocharger and a compound power turbine coupled to said crankshaft, said exhaust gas turbocharger comprising an exhaust gas turbine mounted in an exhaust gas duct of said engine, a compressor operatively connected to said exhaust gas turbine and being mounted in an intake duct of said engine, an exhaust gas recirculation system including a control valve extending between said exhaust duct upstream of said turbine and said intake duct downstream of said compressor for the controlled return of exhaust gas to the intake duct of said engine, and a compound power turbine arranged in said exhaust duct downstream of said exhaust gas turbine and being operatively connected to said crankshaft, said exhaust gas turbine and said compound power turbine having a size relationship determined by the power absorption capability φ of each turbine in accordance with the relationship:

• φ = m . ⁢ T p
• wherein φ is the absorption capability,
• {dot over (m)} is the exhaust gas mass flow rate through the turbine,
• T is the exhaust gas temperature at the turbine inlet,
• and, p is the exhaust gas pressure at the turbine outlet, and the maximal absorption capability φTC,max of the compound power gas turbine exceeds the maximal absorption capability (φATL,max) of the exhaust gas turbine.