Controlling a multiplate clutch situated between an input shaft and an output shaft for the switchable transmission of torques, wherein in the event of a torque request and a subsequent engagement of the multiplate clutch, includes: a) determining a setpoint engagement force, acting in an axial direction, of the multiplate clutch for transmitting a setpoint torque to the output shaft; b) determining and setting a limiting engagement force that is less than the setpoint engagement force, and c) setting the setpoint engagement force in a time-delayed manner;

wherein a transmission of an actual torque is achieved by limiting the setpoint engagement force to the limiting engagement force, so that a maximum actual torque that is transmitted upon engagement of the multiplate clutch exceeds a setpoint torque to be transmitted by at most 5%.

A control apparatus of an all-wheel drive vehicle includes a vehicle speed detector, a first clutch, a second clutch, and a clutch controller. The vehicle speed detector detects a speed of the all-wheel drive vehicle. The first clutch is provided between a parking mechanism and a drive force source of the all-wheel drive vehicle, and adjusts first drive force to be transmitted from the drive force source to an output shaft of an automatic transmission of the all-wheel drive vehicle. The second clutch is provided between the parking mechanism and a drive wheel of the all-wheel drive vehicle, and adjusts second drive force to be transmitted from the output shaft to the drive wheel. The clutch controller controls engagement force of the first and second clutches, and disengages the first and second clutches when the speed of the all-wheel drive vehicle is equal to or less than a predetermined speed.

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.

A control apparatus that controls a four-wheel drive vehicle in which a driving force is transmitted to rear wheels via a dog clutch, a propeller shaft, and a driving force transmission apparatus is configured to, when switching to a four-wheel drive mode, reduce a difference in rotation speeds of an intermediate rotational member and a ring gear member by a frictional force between a friction surface of a friction member, which is configured such that its rotation relative to the intermediate rotational member is restricted, and a target frictional slide surface of the ring gear member, and then couple the intermediate rotational member and the ring gear member by a clutch member in a state in which engagement forces of friction clutches configured to transmit the driving force between each of first and second output rotational members and the intermediate rotational member of the driving force transmission apparatus are set to engagement forces that allow their relative rotation.

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 four-wheel drive vehicle in which, when a switching request is made for switching from a non-meshing state to a meshing state, the control device calculates a first rotation speed difference between the drive-power-source-side meshing teeth and the sub-drive-wheel-side meshing teeth, and a second rotation speed difference between the drive-power-source-side meshing teeth and the sub-drive-wheel-side meshing teeth. If at least one of the calculated first and second rotation speed differences is within a predetermined range set in advance, the control device couples the sub-drive wheel corresponding to the rotation speed difference within the predetermined range, to the central axle by the control coupling to switch the dog clutch from the non-meshing state to the meshing state. And, if neither the calculated first nor second rotation speed difference is within the predetermined range, the control device prohibits switching of the dog clutch from the non-meshing state to the meshing state.

A control device for a power transmission mechanism is provided, performing control so that a driving wheel reliably obtains torque when a vehicle is started. In a vehicle having a power transmission mechanism that includes a power transmission path transmitting power from a power source to a first driving wheel and a second driving wheel, and a power transmission element arranged in the power transmission path between the power source and the second driving wheel, a control device for a power transmission mechanism includes a control section controlling a fastening force of the power transmission element so as to control power transmission capacity of the power transmission mechanism from the power source to the second driving wheel, wherein when the control section acquires that the vehicle transitions from a traveling state to a stop state, the acquisition triggers the control section to increase the power transmission capacity.

A multimode clutch may be adapted for selectively connecting and disconnecting front and/or rear axles from respective internal combustion engine and electric motor powertrains connected to such front and rear driving axles in a through-the-road hybrid vehicle. For example, the engine may be part of a front axle driven powertrain connected to the front wheels, while the motor may be part of a separate rear axle driven powertrain connected to the rear wheels, or vice versa. By selective disconnection of an axle not being actively driven, a real time reduction in parasitic losses may be achieved, leading to higher overall operating efficiencies. The multimode clutch offers greater flexibility over the use of standard friction clutches; each multimode clutch may provide four distinct operational modes for accommodating a wide diversity of driving conditions. For example, bi-rotational freewheeling of the rear axle may occur whenever the motor is not in use.

A control device for a torque distributor provided with a control means acquiring a demand value of a torque distributed to second driving wheels (W3, W4) using a torque distributor (10) and outputs a command value (TR) of torque corresponding to the demand value of torque. When a variation per unit time (ND) of a differential rotation speed (NS) between a drive source (3) side and a second driving wheel side with respect to the torque distributor in a torque transmission path (20) is a predetermined first threshold (ND1) or more, the control means (60) performs a torque command value limit control controlling the torque command value to a predetermined limit value (TR1) or less. This can secure the running stability necessary for the vehicle by distributing an appropriate torque to the second driving wheels using the torque distributor, while enabling proper protection of components including the torque distributor.

According to one embodiment, for example, a transfer control device controls a transfer that adjusts torque distribution to front wheels and rear wheels of a four-wheel vehicle and that includes a wet type multi-disc clutch and a piston. The transfer control device includes: a detector that detects, based on an output value of a sensor provided in the vehicle, whether a predetermined condition corresponding to a state immediately before ignition of the vehicle is turned ON is established; a controller that starts moving the piston when the detector detects that the predetermined condition is established, so that the multi-disc clutch is switched to a connected state from a disconnected state; and a storage that stores therein, while the piston is moved by the controller, information on a connection start state at which connection of the multi-disc clutch is started.