Patent ID: 7428815
Filing Date: 2008-09-30
Classification: F01D,F02B,F02C,F04D,F05D,Y02T

Abstract:
1. A method of operating a compressor ( 5 ) of an exhaust gas turbocharger of an internal combustion engine including an exhaust gas turbine with a variable turbine inlet geometry coupled to the compressor near the compressor pumping limit wherein the compressor includes a control arrangement for adjusting the momentary operating state of the compressor, the method comprising the steps of: measuring the flow velocity v 3 of a mass flow through the compressor ( 5 ) in the boundary layer along the wall of a flow passage through the compressor, determining an operation of the compressor near the pumping limit from a reversal of the direction of a mass flow vector in the boundary layer, and actuating the control arrangement for stabilizing compressor operation so as to prevent the compressor from transgressing the pumping limit, wherein, when the mass flow through the compressor reaches a first flow velocity threshold value (v s,1 ), one of an actuating mechanism for adjusting a variable compressor geometry and an actuating mechanism for adjusting a variable turbine geometry is operated, when the mass flow through the compressor reaches a second flow velocity threshold value (v s,2 ), the other of the actuating mechanism for adjusting a variable compressor geometry and the actuating mechanism for adjusting a variable turbine geometry is operated and, finally, when the mass flow through the compressor reaches a third flow velocity threshold value (v s, 3 ), an actuating mechanism for reducing the fuel amount injected into the cylinders of the internal combustion engine is operated.