A method and a device for operating a drive train of a motor vehicle are provided. The drive train includes at least a first and a second shaft, a first clutch having at least one first friction surface pairing, and an electric drive, the first and the second shaft being coupleable to one another via the at least one first friction surface pairing, wherein for cooling the first clutch, a fluid is used via which a drag torque of the first clutch is influenced after the first clutch is disengaged, the method including: a) Rotating the first shaft and the second shaft when the first clutch is at least partially engaged; b) Disengaging the first clutch; c) Accelerating the first shaft by means of the electric drive and discharging the fluid from an area of the at least one first friction surface pairing;
wherein the drag torque of the first clutch is reduced by the accelerated discharge of the fluid.

A method for reducing overheating in a clutch assembly having a clutch housing, a shaft, and a clutch pack. The clutch pack includes a backing plate, an applied plate, a plurality of friction plates, and a plurality of reaction plates. A primary actuator applies pressure to the applied plate to longitudinally compress the entire clutch pack and couple rotation of the clutch housing and the shaft. A secondary actuator applies pressure to at least one plate in the plurality of friction plates and the plurality of reaction plates to longitudinally move the at least one plates independently of the applied plate. This relieves some of the torque transmitted across the clutch pack adjacent the applied plate and reduces localized temperature spikes in the clutch pack adjacent to the applied plate.

A device that employs shear forces to transmit energy includes an outer housing assembly, a disk, and a reservoir with a working fluid. The disk is received in and rotatable relative to the outer housing assembly. A working cavity is formed between a rotor portion of the disk and the outer housing assembly into which the working fluid is received to create shear forces. A plurality of flow altering structures are disposed on the outer housing assembly and are configured to reduce a thickness of a boundary layer of the working fluid in the working cavity in areas that are local to the flow altering structures.

A device that employs shear forces to transmit energy includes an outer housing assembly, a disk, and a reservoir with a working fluid. The disk is received in and rotatable relative to the outer housing assembly. A working cavity is formed between a rotor portion of the disk and the outer housing assembly into which the working fluid is received to create shear forces. A plurality of flow altering structures are disposed on the outer housing assembly and are configured to reduce a thickness of a boundary layer of the working fluid in the working cavity in areas that are local to the flow altering structures.

A method for reducing overheating in a clutch assembly having a clutch housing, a shaft, and a clutch pack. The clutch pack includes a backing plate, an applied plate, a plurality of friction plates, and a plurality of reaction plates. A primary actuator applies pressure to the applied plate to longitudinally compress the entire clutch pack and couple rotation of the clutch housing and the shaft. A secondary actuator applies pressure to at least one plate in the plurality of friction plates and the plurality of reaction plates to longitudinally move the at least one plates independently of the applied plate. This relieves some of the torque transmitted across the clutch pack adjacent the applied plate and reduces localized temperature spikes in the clutch pack adjacent to the applied plate.

A device that employs shear forces to transmit energy includes an outer housing assembly, a disk, and a reservoir with a working fluid. The disk is received in and rotatable relative to the outer housing assembly. A working cavity is formed between a rotor portion of the disk and the outer housing assembly into which the working fluid is received to create shear forces. A plurality of flow altering structures are disposed on the outer housing assembly and are configured to reduce a thickness of a boundary layer of the working fluid in the working cavity in areas that are local to the flow altering structures.

An electromagnetic actuating device for a torque transmission system includes a shell arranged around an axis X, the shell being fixed relative to the axis X. The shell includes walls defining an annular cavity which houses a coil and at least partially a plunger which is able to move axially along the axis X to actuate a coupling device.

A clutch assembly that is less prone to overheating is disclosed. The clutch assembly includes a clutch housing, a shaft, and a clutch pack. The clutch pack includes a backing plate, an applied plate, a plurality of friction plates, and a plurality of reaction plates. A primary actuator applies pressure to the applied plate to longitudinally compress the entire clutch pack and couple rotation of the clutch housing and the shaft. A secondary actuator applies pressure to at least one plate in the plurality of friction plates and the plurality of reaction plates to longitudinally move the at least one plates independently of the applied plate. This relieves some of the torque transmitted across the clutch pack adjacent the applied plate and reduces localized temperature spikes in the clutch pack adjacent to the applied plate.

An oil pressure supply system distributes lubrication for a dual clutch transmission and an includes a mechanical oil pump pumping oil stored in a sump while being driven by an engine; a line regulator valve directly supplying a lubrication flow rate to an input shaft and a counter shaft by controlling the oil pressure supplied from the mechanical oil pump and simultaneously supplying the lubrication flow rate to a gear train and clutch through another path; a line pressure control valve variably exhausting the lubrication oil pressure when the lubrication oil pressure supplied to the input shaft and the counter shaft is a predetermined value or more; an electric oil pump pumping the oil depending on a control of a transmission control unit; a first lubrication switch valve selectively blocking oil pressure supplied from the electric oil pump to the gear train and the clutch; and a second lubrication switch valve switching a flow path so that oil pressure supplied from the line regulator valve and the first lubrication switch valve is selectively supplied to the gear train and the clutch.

An internal combustion engine including a cooling liquid circuit, which is connected to a cylinder head and an engine block of the internal combustion engine and which includes a cooling liquid pump. The cooling liquid pump includes a drive shaft and is capable of conveying cooling liquid in the cooling liquid circuit. Further, the internal combustion engine includes a Visco clutch. The Visco clutch is arranged for the drive by the internal combustion engine. The Visco clutch includes a clutch fluid for torque transmission. At the output side, the Visco clutch is connected to the drive shaft of the cooling liquid pump. The drive shaft of the cooling liquid pump include at least one heat pipe. The heat pipe is in heat exchange with the clutch fluid as a heat source and the cooling liquid as a heat sink.