Patent ID: 8152689

Claim:
A method of operating a hydraulic pump ( 11 ) of a drive train of a motor vehicle having a transmission with a hydrodynamic torque converter ( 16 ) and a drive engine ( 10 ), the method comprising the steps of: coupling the hydraulic pump ( 11 ) with the torque converter ( 16 ), which is coupled to the drive engine ( 10 ), such that an input speed of the hydraulic pump ( 11 ) is adjusted in dependence on a speed of a turbine (T) of the torque converter ( 16 ) and a speed of the torque converter ( 16 ), which corresponds to a speed of the drive engine ( 10 ); operating the hydraulic pump ( 11 ) at a speed higher than the speed of the drive engine ( 10 ) when a speed of a pump (P) of the torque converter ( 16 ) is higher than the speed of the turbine (T) of the torque converter ( 16 ); reducing the operating speed of the hydraulic pump ( 11 ) in relation to the speed of the drive engine ( 10 ) when the speed of the turbine (T) of the torque converter ( 16 ) approaches the speed of the pump (P) of the torque converter ( 16 ); operating the hydraulic pump ( 11 ) at a maximally increased speed in relation to the speed of the drive engine ( 10 ) when the motor vehicle is stationary and the drive engine ( 10 ) is running and thus the speed of the pump (P) of the torque converter ( 16 ) corresponds to the speed of the drive engine ( 10 ) and the speed of the turbine (T) of the torque converter ( 16 ) is approximately zero; and operating the hydraulic pump ( 11 ) at a speed that corresponds to the speed of the drive engine ( 10 ) when the motor vehicle is in a drive operation and the speed of the pump (P) of the torque converter ( 16 ) corresponds to the speed of the turbine (T) of the torque converter ( 16 ).