Patent ID: 7073334

Claim:
A method for controlling the rotational speed of a variable exhaust gas turbocharger ( 1 ) of a controllable internal combustion engine ( 10 ) with a compressor ( 3 ) which has radial input end and output areas wherein an adjustable radial inflow guide vane structure ( 4 ) is disposed in a constant-width radial flow duct upstream of the compressor wheel ( 3 . 1 ) in the direction of flow so that the vane structure as adjustable over a range of âˆ’90Â° to +90Â°, wherein a) during a switching phase, a controllable swirl in the opposite direction from the direction of flow is generated against the compressor wheel ( 3 . 1 ), as a result of which the exhaust gas turbocharger ( 1 ) is braked and/or b) during an engine braking phase, the position of the variable vane structure ( 4 ) with swirl in the direction opposite to the direction of flow is formed in the inflow duct ( 3 . 3 ), as a result of which the rotational speed of the exhaust gas turbocharger ( 1 ) is limited in a controllable fashion and c) during a steady-state phase, a controllable swirl in the same direction as the flow with pressure reduction over the entire compressor is generated against the compressor wheel ( 3 . 1 ), as a result of which the compressor ( 3 ) operates as a turbine.