Patent ID: 7993241
Filing Date: 2011-08-09
Classification: F16H,Y10T

Abstract:
1. Method for controlling an upshift process in a dual-clutch gearbox having a dual-clutch gearbox input shaft connected to a drive engine, having two friction clutches and having two partial gearboxes, the method comprising the steps: detecting a demand for a shift from a low source gear into a higher target gear, with the source gear and the target gear being assigned to one of the two partial gearboxes of the dual-clutch gearbox, opening the friction clutch which is assigned to the one partial gearbox and closing the friction clutch assigned to the other partial gearbox in order to transmit drive power via an intermediate gear of the other partial gearbox without an interruption in tractive force, with the rotational speed of the dual-clutch gearbox input shaft being reduced in this way, disengaging the source gear and conducting temporarily a pressure-exertion process in the friction clutch assigned to the one partial gearbox before the engagement of the target gear, with the rotational speed of the one partial gearbox being reduced as a result of the pressure-exerting process by virtue of a drag torque being transmitted to the one partial gearbox by the dual-clutch gearbox input shaft which is rotating at a reduced rotational speed, such that a synchronization of the target gear may be begun at a reduced differential rotational speed, and opening the friction clutch assigned to the other partial gearbox and closing the friction clutch assigned to the one partial gearbox in order to transfer drive power to the target gear without an interruption in tractive force, wherein the pressure-exertion process is carried out according to at least one of: when the differential rotational speed is greater than a certain threshold value, when a sliding speed of a friction ring of a target shift clutch is greater than a certain threshold value, and when the rotational speed of the one partial gearbox is greater than the rotational speed of the dual-clutch gearbox input shaft.