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.

Methods and systems are provided for estimating a maximum available torque reserve prior to a gear upshift and then during the upshift, generating the torque reserve to fill a torque hole. In one example, a method may include estimating a maximum torque reserve based on each of a driver torque demand, an auxiliary system demand, and a maximum generable engine torque and then opportunistically generating the torque reserve.

A method for, during creep mode, performing gearshift in a vehicle powertrain comprising a combustion engine, a gearbox, and a clutch is provided. The method comprises, in response to a request for gearshift, disconnecting the combustion engine from the gearbox by opening the clutch. The method further comprises, when the combustion engine is disconnected from the gearbox, shifting the gearbox and controlling the speed of the combustion engine to a target speed. Said target speed constitutes a combustion engine speed corresponding a desired combustion engine torque for completing a torque ramp during closing of the clutch. The method further comprises connecting the combustion engine to the gearbox by closing the clutch. A control device configured to perform the method and a vehicle comprising the control device are also provided.

Methods and systems are provided for estimating a maximum available torque reserve prior to a gear upshift and then during the upshift, generating the torque reserve to fill a torque hole. In one example, a method may include estimating a maximum torque reserve based on each of a driver torque demand, an auxiliary system demand, and a maximum generable engine torque and then opportunistically generating the torque reserve.

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.

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.

Provided are gearboxes including compound planet gear assemblies as well as methods of using such gearboxes. A gearbox includes at least a first ring gear and a second ring gear. Depending on the current gear selection, one of these ring gears may be engaged with a shifting mechanism or not engaged with any ring gears when in a neutral gear. The first ring gear may be constantly engaged with a first planet gear of a compound planet gear assembly, while the second ring gear may be constantly engaged with a second planet gear of the same compound planet gear assembly. The first planet gear may be also engaged with a sun gear coupled to a shaft. Another shaft is coupled to the shifting mechanism. Different gear selections of the gearbox engage different ring gears to the shifting mechanism thereby changing the rotational speed ratio of the two shafts.

A method for, during creep mode, performing gearshift in a vehicle powertrain comprising a combustion engine, a gearbox, and a clutch is provided. The method comprises, in response to a request for gearshift, disconnecting the combustion engine from the gearbox by opening the clutch. The method further comprises, when the combustion engine is disconnected from the gearbox, shifting the gearbox and controlling the speed of the combustion engine to a target speed. Said target speed constitutes a combustion engine speed corresponding a desired combustion engine torque for completing a torque ramp during closing of the clutch. The method further comprises connecting the combustion engine to the gearbox by closing the clutch. A control device configured to perform the method and a vehicle comprising the control device are also provided.