Patent ID: 7937942

Claim:
A turbocharger system for an internal combustion engine ( 10 ) having at least one exhaust line ( 15 , 16 ) for evacuating exhaust gases from the combustion chamber ( 11 ) of the engine and at least one inlet line ( 12 ) for supplying air to said combustion chamber, the turbocharger system includes a high-pressure turbine ( 17 ) interacting with a high-pressure compressor ( 19 ) and a low-pressure turbine ( 21 ) of the axial type interacting with a low-pressure compressor ( 23 ) for extracting energy from the exhaust flow of the engine and pressurizing the inlet air of the engine, both compressor stages are of the radial type and are provided with compressor wheels having backswept blades ( 35 ) in which the blade angle, (β 2 ), between an imaginary extension of the centerline of the blade between root section and tip section in the direction of the outlet tangent and a line ( 36 ) connecting the center axis of the compressor wheel to the outer point of the blade, is at least about 40 degrees, the high-pressure turbine ( 17 ) is of the radial type and is connected to the low-pressure turbine by an intermediate duct ( 20 ) and the low-pressure turbine ( 21 ) is provided with inlet guide rails ( 34 ) and wherein the high-pressure turbine ( 17 ) which drives the high-pressure compressor ( 19 ) is of the radial type, having a turbine wheel which has a small diameter and a recess-free hub.