Methods and systems are provided for a dual motor electric transmission configured with two dual synchronizers to reduce torque interruption during gear shifting. In one example, a method may include dropping torque of a first electric motor, allowing a first synchronizer to shift from a first gear arrangement to a second gear arrangement, and compensating for dropped torque with a second electric motor. The method may be repeated to shift a second synchronizer from the first gear arrangement to the second gear arrangement, allowing uninterrupted torque supply during gear shifting.

During a transmission upshift, a torque capacity of an off-going clutch is maintained at a non-zero state during the transition from the torque phase to the inertia phase and throughout a substantial portion of the inertia phase. This permits the inertia phase to be completed faster without an unacceptable increase in output torque during the torque phase. Monotonically reducing the off-going clutch torque and using feedback from an output torque sensor enable sufficiently precise control of the off-going clutch torque capacity during this interval.

Systems and methods for an electric powertrain. The method, in one example, includes responsive to receiving a shift command, engaging a second friction clutch while disengaging a first friction clutch to transition from a first operating gear ratio to a second operating gear ratio. The method, further includes during the gear ratio transition, operating a traction motor under a peak condition, the peak condition denotes a condition where the motor speed is greater than a maximum continuous torque curve of the motor.

A method is provided to control a hybrid powertrain comprising an internal combustion engine, a gearbox, a range gearbox, and two electrical machines to achieve a shift operation from a low range position to a high range position with minimal to no torque interruption and optimal brake regeneration, on the one hand, and a large torque and a lame number of gear steps are achieved on the other hand.

A method is provided for controlling a hybrid powertrain comprising a combustion engine, a gearbox, a range gearbox, and two electrical machines to achieve a shift operation from a low range position to a high range position with minimal to no torque interruption and optimal brake regeneration, on the one hand, and a large torque and a large number of gear steps are achieved on the other hand.

During a transmission upshift, a torque capacity of an off-going clutch is maintained at a non-zero state during the transition from the torque phase to the inertia phase and throughout a substantial portion of the inertia phase. This permits the inertia phase to be completed faster without an unacceptable increase in output torque during the torque phase. Monotonically reducing the off-going clutch torque and using feedback from an output torque sensor enable sufficiently precise control of the off-going clutch torque capacity during this interval.

In a power transmission device in which a first power transmission path is formed by engagement of a first clutch and a dog clutch and a second power transmission path is formed by engagement of a second clutch, the first clutch is released from a state where the first clutch and the dog clutch are engaged, and when a front-rear rotation speed difference of the dog clutch becomes equal to or greater than a predetermined value after the start of a clutch-to-clutch gear shift for engaging the second clutch, complete release control for releasing the first clutch to lower the torque capacity of the first clutch is performed.

A method for changing between a multiplicity of discrete transmission ratio stages in a motorcycle gearbox is provided. In response to a shift demand, during the torque-transmitting connection of a drive shaft of the drive machine to a gearbox input shaft, a gear-selection drum of the transmission is rotatable from a first shifting position to an intermediate position which is situated between the first and a second shifting position, before shifting to the second shift position. In the intermediate position, no drive torque can be transmitted from the gearbox input shaft to a gearbox output shaft. During the gear selection drum movement from the first shifting position and the intermediate position, the drum may be rotated to a rest position in which drive torque can be transmitted from the gearbox input shaft to a gearbox output shaft.

A method is provided to control a hybrid powertrain comprising engaging gears corresponding to a first gear pair connected with a first planetary gear in a gearbox with a first coupling device connecting two rotatable components in the first planetary gear; activating a second electrical machine to generate a propulsion torque on the output shaft via a second gear pair connected with a second planetary gear and the output shaft; disconnecting the first gear pair from the countershaft, by controlling the first electrical machine and a combustion engine connected with the first planetary gear to achieve a substantially zero torque state between the first gear pair; connecting the first gear pair to the countershaft, by controlling the combustion engine to achieve a synchronous rotational speed between the first gear pair; and activating the combustion engine and/or the first electrical machine to generate a propulsion torque on the output shaft.

A control system of a vehicle includes an automatic transmission provided with a plurality of friction engagement elements changeable between engaged and disengaged states, and configured to form a plurality of gear stages by changing a combination of three friction engagement elements to be selectively engaged among the friction engagement elements, and a controller which controls the change between the engaged and disengaged states of each friction engagement element. The controller performs a neutral control in which, for setting the automatic transmission to a neutral state in which a driving force of a drive source is not transmitted to driving wheels, while two of the three friction engagement elements engaged when forming each gear stage are kept engaged, the remaining one of the three friction engagement element is disengaged. The two friction engagement elements engaged during the neutral control are common in at least two adjacent gear stages.