Abstract: A two stage turbocharger for an internal combustion engine, the two stage turbocharger comprising a high pressure turbine fluidly connected to an exhaust manifold of the engine through a high pressure turbine inlet duct and a low pressure turbine fluidly connected to the high pressure turbine through a low pressure turbine inlet duct, wherein the low pressure turbine is a variable geometry turbine, wherein the two stage turbocharger comprise a bypass duct system to bypass the variable geometry low pressure turbine, wherein the bypass duct system comprises a bypass valve.

Abstract: A two stage turbocharger for an internal combustion engine, the two stage turbocharger comprising a high pressure turbine fluidly connected to an exhaust manifold of the engine through a high pressure turbine inlet duct and a low pressure turbine fluidly connected to the high pressure turbine through a low pressure turbine inlet duct, wherein the low pressure turbine is a variable geometry turbine, wherein the two stage turbocharger comprise a bypass duct system to bypass the variable geometry low pressure turbine, wherein the bypass duct system comprises a bypass valve.

Abstract: In an internal combustion engine, a two stage turbocharger is disclosed including a low pressure turbine and the high pressure turbine are arranged in series. The high pressure turbine is connected to an exhaust manifold of the engine through a high pressure turbine inlet duct. The low pressure turbine is connected to the high pressure turbine through a low pressure turbine inlet duct and to the high pressure turbine inlet duct through a connecting channel. The two stage turbocharger is provided with a bypass system including a high pressure turbine valve arranged in the high pressure turbine inlet duct, and a low pressure turbine valve arranged in the connecting channel. An actuator is configured to operate the high pressure turbine valve and the low pressure turbine valve to alternatively close the high pressure turbine inlet duct or the connecting channel.

Abstract: A turbocharger system for an internal combustion engine is disclosed which includes a variable-geometry-turbine having movable vanes, an electric actuator coupled to rotate the movable vanes. An electronic control unit is configured to operate the electric actuator for rotating the movable vanes until they reach a mechanical stop corresponding to a fully-open position. A position sensor learns the position value of the movable vanes, once they have reached the mechanical stop.