Patent ID: 6854272

Claim:
An exhaust gas turbocharger for an internal combustion engine, having an exhaust gas turbine, which is arranged in the exhaust system of the internal combustion engine, and a compressor, which is arranged in the induction system and is connected to the exhaust gas turbine by means of a shaft, having variable turbine geometry associated with the exhaust gas turbine for adjustably setting a radial flow inlet cross section to the turbine rotor between a back-pressure position which reduces the inlet flow cross section and an open position which increases the inlet flow cross section, the variable turbine geometry being configured as a guide cascade, which encompasses the turbine rotor and has guide vanes distributed around the periphery, and adjacent guide vanes having a minimum distance apart (b min ) in the back-pressure position in order to secure a flow path in the direction of the turbine rotor, wherein the minimum distance (b min ) between two adjacent guide vanes in the back-pressure position is b min ≦0.5 D TR /z, where D TR designates the diameter of the turbine rotor, z designates the number of guide vanes of the guide cascade, and in that there is a flow edge on the radially inner surface of each guide vane—on the surface facing towards the adjacent guide vane—the flow edge including an angle (α), which obeys the relationship α = k ⁢ ⁢ arctan ⁡ ( 1 k ⁢ M 2 - 1 ) - arctan ⁡ ( M 2 - 1 ) , k = κ + 1 κ - 1 where M designates an average Mach number in the region of the guide vane trailing edge, κ designates the isentropic exponent.