The invention relates to a method for operating a vehicle drive train (1) comprising a prime mover (2), comprising a transmission (3), and comprising a driven end (4). A friction-locking shift element (10) is provided, the power transmission capacity of which is variable and, with the aid of which, at least a portion of the torque transmitted in the vehicle drive train (1) can be transmitted between a transmission output shaft (8) and an area (6) of the driven end (4). One shift-element half is operatively connected to the transmission output shaft (8) and the other shift-element half is operatively connected to the area (6) of the driven end (4). The rotational speed of the transmission output shaft (8) is determined as a function of the rotational speed in the area (6) of the driven end (4) and also as a function of the rotational speed of the prime mover (2) and the ratio currently engaged in the area of the transmission (3). In the event of a deviation between the rotational speed of the transmission output shaft (8) determined on the output end and the rotational speed of the transmission output shaft (8) determined on the transmission-input end, which is greater than or equal to a threshold value and/or an operating temperature in the area of the friction-locking shift element (10), which is greater than or equal to a limiting value, measures reducing loads of the friction-locking shift element (10) are initiated.

A method for controlling a separating clutch in a power train of a vehicle having a drive motor and a retarder. The clutch is arranged such that a rotor of the retarder is switched into a drive connection with the motor and/or power train via the clutch and a working chamber of the retarder can be filled with an operating medium to build up a braking power such that braking torque is exerted by the retarder onto the power train and/or motor. A control system switches the clutch into a closed or an open position. The switching of the clutch into the closed position occurs depending on an input signal to the controller, and the clutch is switched back into the open position depending on essentially no medium being present in the working chamber of the retarder and that predetermined limits of an operating and/or environmental parameter are not exceeded.

A method (200) for the open-loop control of a gearbox (100) that includes a first and a second proportionally controllable shift element (A-F) is provided. The method includes disengaging (215) the first shift element (A-F) according to a first control profile and engaging (220) the second shift element (A-F) of the gearbox (100) according to a second control profile. The first control profile includes a first variable portion which is determined as a function of a temperature of the gearbox (100).

Methods and systems are provided for operating a powertrain or driveline of a hybrid vehicle that includes two electric machines and a transmission are described. In one example, vehicle propulsion is maintained while transmission operating parameters are determined for improving transmission operation. In particular, a rear drive unit maintains vehicle speed and monitors torque delivered via an output of the transmission.

In a dutch engagement control system for engagement and disengagement of transmission of a rotational force between a mainshaft and a countershaft, when clutch engagement control is executed based on the determination that rotational speeds of both the shafts agree with each other, even if unexpected variations in countershaft rotational speed result from torsion occurring downstream of the countershaft in a drive system and/or the like, smooth engagement control is implemented. A control value of countershaft rotational speed at each time is updated and managed. If a threshold value is exceeded by a difference between a countershaft rotational speed actual measured value and the preceding control value, the threshold value is added to the preceding value to obtain the control value. If the threshold value does not exceed the difference, the actual measured value at this time is set as a control value without any change.

A method for controlling a separating clutch in a power train of a vehicle having a drive motor and a retarder. The clutch is arranged such that a rotor of the retarder is switched into a drive connection with the motor and/or power train via the clutch and a working chamber of the retarder can be filled with an operating medium to build up a braking power such that braking torque is exerted by the retarder onto the power train and/or motor. A control system switches the clutch into a closed or an open position. The switching of the clutch into the closed position occurs depending on an input signal to the controller, and the clutch is switched back into the open position depending on essentially no medium being present in the working chamber of the retarder and that predetermined limits of an operating and/or environmental parameter are not exceeded.

A method of drivingly engaging a first motor of a dual motor drive unit with an output shaft driven by a second motor of the dual motor drive unit includes actuating a clutching device for drivingly engaging the first motor with the output shaft. Next, a rotational speed of the first motor is synchronized with a rotational speed of the output shaft. When the rotational speed of the first motor and the rotational speed of the output shaft are synchronized, an output torque of the first motor is reduced. When the clutching device drivingly engages the first motor with the output shaft, the output torque of the first motor is increased. The invention further relates to a dual motor drive unit for carrying out the method.

A method for coupling a first sub-shaft, which has a first turbomachine and a generator connected to a mains supply, to a second sub-shaft, which has a second turbomachine, by means of an overrunning clutch, has the following steps: a) rotating the second sub-shaft with a starting rotational speed which is lower than the rotational speed of the first sub-shaft; b) measuring the mains frequency of the mains supply; c) measuring a differential angle between the first sub-shaft and the second sub-shaft; d) accelerating the second sub-shaft with an acceleration value which is produced using the mains frequency measured in step b), the differential angle and the starting rotational speed, and therefore the overrunning clutch couples the two sub-shafts to each other with a previously determined target coupling angle.

A clutch disengagement position is detectable with high precision even during speed change. A vehicle transmission device can include a transmission including a main shaft to which rotational power from an engine is inputted via a clutch, and a countershaft, a clutch operation member that is driven by an actuator and performs disengaging and engaging operations of the clutch, and a driving wheel to which rotational power of the countershaft is transmitted via a driving force transmitting device. A damper member deformed by a driving force is provided in the countershaft, the driving force transmitting device or the driving wheel, or among the countershaft, the driving force transmitting device and the driving wheel. A control device learns a clutch disengagement operation amount when the control device detects deceleration of a predetermined value of the rotational frequency of the main shaft.

A method for operating a drive train for a motor vehicle, with at least one primary drive axle and at least one secondary drive axle, which are operatively connected to each other via a clutch to an adjustable transmission torque. At the same time it is provided that a vibration amplitude of a vibration of the drive train is determined and in a damping operation type of the drive train, the transmission torque is determined from the vibration amplitude and adjusted on the clutch.