A vehicle includes a primary axle powered by an actuator and a secondary axle powered by a motor. The secondary axle includes a differential, first and second halfshafts, first and second wheels, a first electric clutch selectively coupling the first wheel to the first halfshaft, and a second electric clutch selectively coupling the second wheel to the second halfshaft. A vehicle controller is programmed to: responsive to a request to activate the secondary axle and a first speed difference between the first and second wheels being less than a first threshold, engage the first and second clutches at a same time, and, in response to the request to activate the secondary axle and the first speed difference between the first and second wheels exceeding the first threshold, engage one of the clutches and then subsequently engage the other of the clutches once the one of the clutches is fully engaged.

A vehicle includes a primary axle powered by an actuator and a secondary axle powered by a motor. The secondary axle includes a differential, first and second halfshafts, first and second wheels, a first electric clutch selectively coupling the first wheel to the first halfshaft, and a second electric clutch selectively coupling the second wheel to the second halfshaft. A vehicle controller is programmed to: responsive to a request to activate the secondary axle and a first speed difference between the first and second wheels being less than a first threshold, engage the first and second clutches at a same time, and, in response to the request to activate the secondary axle and the first speed difference between the first and second wheels exceeding the first threshold, engage one of the clutches and then subsequently engage the other of the clutches once the one of the clutches is fully engaged.

A method for multi-speed electric vehicle shift control for damping an acceleration oscillation of the electric vehicle. The method includes determining a percentage of accelerator pedal travel and then retrieving a clutch calibration, a first electric motor calibration, and a second electric motor calibration correlating with the determined percentage of accelerator pedal travel. The method then applies the clutch calibration in actuating a clutch-to-clutch gear ratio change, thereby generating a vibration fluctuation in a first axle, and applies the first electric motor calibration in modulating a first electric motor to dampen the vibration fluctuation. The clutch actuation and first electric motor modulation together produces a first axle torque oscillation. The method applies the second electric motor calibration in modulating the second electric motor to generate a second axle torque oscillation sufficiently out-of-phase with the first axle torque oscillation, thereby dampening the vehicle acceleration oscillation of the electric vehicle.

A method for multi-speed electric vehicle shift control for damping an acceleration oscillation of the electric vehicle. The method includes determining a percentage of accelerator pedal travel and then retrieving a clutch calibration, a first electric motor calibration, and a second electric motor calibration correlating with the determined percentage of accelerator pedal travel. The method then applies the clutch calibration in actuating a clutch-to-clutch gear ratio change, thereby generating a vibration fluctuation in a first axle, and applies the first electric motor calibration in modulating a first electric motor to dampen the vibration fluctuation. The clutch actuation and first electric motor modulation together produces a first axle torque oscillation. The method applies the second electric motor calibration in modulating the second electric motor to generate a second axle torque oscillation sufficiently out-of-phase with the first axle torque oscillation, thereby dampening the vehicle acceleration oscillation of the electric vehicle.

A vehicle power distribution control method, apparatus and system are provided. The method includes: acquiring an image of a road surface on which a vehicle drives currently, and recognizing, according to the image of the road surface, the type of the road surface on which the vehicle drives currently; starting a corresponding terrain mode in an all-terrain adaptive mode according to the current type of the road surface; determining a power distribution strategy corresponding to the current terrain mode according to a correspondence between terrain modes and preset power distribution strategies; and switching a center differential of the vehicle to a corresponding locking mode according to the current power distribution strategy, and distributing, in the locking mode, torques to front and rear axles of the vehicle according to a torque distribution curve corresponding to the current power distribution strategy. The front and rear axles of a four-wheel drive vehicle can be conveniently provided with adequate torques on different road surfaces.

A vehicle power distribution control method, apparatus and system are provided. The method includes: acquiring an image of a road surface on which a vehicle drives currently, and recognizing, according to the image of the road surface, the type of the road surface on which the vehicle drives currently; starting a corresponding terrain mode in an all-terrain adaptive mode according to the current type of the road surface; determining a power distribution strategy corresponding to the current terrain mode according to a correspondence between terrain modes and preset power distribution strategies; and switching a center differential of the vehicle to a corresponding locking mode according to the current power distribution strategy, and distributing, in the locking mode, torques to front and rear axles of the vehicle according to a torque distribution curve corresponding to the current power distribution strategy. The front and rear axles of a four-wheel drive vehicle can be conveniently provided with adequate torques on different road surfaces.

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.

Operating a drive train of a vehicle having a clutch assembly, wherein the clutch assembly is actuatable via an actuating device for the switchable transmission of a torque, wherein a first state of the actuating device, and thus a second state of the clutch assembly, is settable via a position of a drive unit of the actuating device, comprises: a) determining that a first torque request to the clutch assembly is constant; and b) determining that a first position of the drive unit is constant within the interval; and then c) controlling the drive unit with a dither function, wherein a position of the drive unit is continuously varied about the first position; and d) ending the dither function when the conditions stated in steps a) and b) are no longer met.

Operating a drive train of a vehicle having a clutch assembly, wherein the clutch assembly is actuatable via an actuating device for the switchable transmission of a torque, wherein a first state of the actuating device, and thus a second state of the clutch assembly, is settable via a position of a drive unit of the actuating device, comprises: a) determining that a first torque request to the clutch assembly is constant; and b) determining that a first position of the drive unit is constant within the interval; and then c) controlling the drive unit with a dither function, wherein a position of the drive unit is continuously varied about the first position; and d) ending the dither function when the conditions stated in steps a) and b) are no longer met.

A motor vehicle sets a front wheel average rotation speed that is an average rotation speed of left and right front wheels, based on a rotation speed of a first motor, and sets a rear wheel average rotation speed that is an average rotation speed of left and right rear wheels, based on a rotation speed of a second motor. When a difference between the front wheel average rotation speed and the rear wheel average rotation speed is larger than a first reference value, the motor vehicle sets a vehicle body speed, based on the lower between the front wheel average rotation speed and the rear wheel average rotation speed. The motor vehicle compares a difference between the vehicle body speed and the wheel speed of each wheel, with a second reference value and thereby determines whether the wheel idles.