Compressor

Abstract

A turbocharger unit for an internal combustion engine having at least one exhaust line for the evacuation of exhaust gases from the combustion chamber of the engine and at least one inlet line for the supply of air to the combustion chamber is provided. The turbocharger unit includes a turbine which interacts with a compressor in order to extract energy from the exhaust-gas flow of the engine and pressurize the inlet air of the engine. The compressor is of the radial type and is provided with an impeller having backswept blades in which the blade angle between an imaginary extension of the center line of the blade between root section and tip section in the direction of the outlet tangent and a line connecting the center axis of the impeller to the outer tip of the blade is at least about 40 degrees. The ratio between the inlet diameter of the impeller and its outlet diameter lies within the range 0.50-0.62. The compressor diffuser is provided with blades, the length of which has a ratio to the distance between them, along the periphery in the blade inlet, within the range 0.7-1.5.

1 . A turbocharger unit for an internal combustion engine having at least one exhaust line for the evacuation of exhaust gases from the combustion chamber of the engine and at least one inlet line for the supply of air to the combustion chamber, comprising a turbine, which interacts with a compressor in order to extract energy from the exhaust-gas flow of the engine and pressurize the inlet air of the engine, wherein the compressor is of the radial type and is provided with an impeller having backswept blades in which the blade angle, between an imaginary extension of the center line of the blade between root section and tip section in the direction of the outlet tangent and a line connecting the center axis of the impeller to the outer tip of the blade, is at least about 40 degrees, and the ratio between the inlet diameter of the impeller and its outlet diameter lies within the range 0.50-0.62, and is further provided with a diffuser, which is provided with blades, the length of which has a ratio to the distance between them, along the periphery in the blade inlet, within the range 0.7-1.5, for diminishing velocity difference between the flow along a pressure side and a suction side of the blade for increasing compressor efficiency. 
     
     
         2 . The turbocharger unit as claimed in  claim 1 , wherein the blade angle is at least about 45°, 
     
     
         3 . The turbocharger unit as claimed in  claim 1  wherein the blade inclines, at an angle of inclination greater than 0 degrees, in the direction of rotation in the outlet of the impeller. 
     
     
         4 . The turbocharger unit as claimed in  claim 1  wherein the angle of inclination is at least about 30 degrees. 
     
     
         5 . The turbocharger unit as claimed in  claim 1  wherein the impeller is machine-worked from an aluminum alloy forging. 
     
     
         6 . The turbocharger unit as claimed in  claim 1  wherein the impeller is machine-worked from a titanium alloy.