VARIABLE NOZZLE TURBOCHARGER HAVING CAMBERED VANES

摘要

There is provided a turbocharger with a variable nozzle assembly having a plurality of cambered vanes positioned annularly around a turbine wheel, each vane (20) being pivotable around a pivot point (Pp) and being configured to have a leading edge (Ple) and a trailing edge (Pte) connected by an outer airfoil surface (2) and an inner airfoil surface (4), said outer airfoil surface (2) being substantially convex and said inner airfoil surface (4) having a convex section at the leading edge (Ple) which has a local extreme (Pex) of curvature and transitions into a concave section towards the trailing edge (Pte). The positions of the pivot point (Pp) and the local extreme (Pex) are set such that, even when the vanes are placed in a closed position, the exhaust gas stream exercises a positive torque on the vanes which tends to open the nozzle.