A method is provided to control a hybrid powertrain to achieve gear shifts without torque interruption, comprising a gearbox with input shaft and output shafts; a first planetary gear connected to the input shaft and a first main shaft; a second planetary gear connected to the first planetary gear and a second main shaft; first and second electrical machines respectively connected to the first and second planetary gears; a first gear pair and a third gear pair between the first main shaft and a countershaft; and a second gear pair between the second main shaft and the countershaft, which is connected with the output shaft via a fifth gear pair. The method comprises disconnecting the first gear pair; connecting the first planetary gear with the output shaft via a coupling mechanism connecting the first main shaft and output shaft; disconnecting the fifth gear pair; transferring torque generated from the combustion engine from the second planetary gear to the countershaft via the second gear pair; and transferring a torque from the countershaft to the output shaft via the third gear pair.

A power transmission system of a vehicle and a gear-shift control method are provided. The power transmission system includes a first drive assembly (101) and a second drive assembly (102). The first drive assembly includes a first automatic transmission (2) and a first motor (1) connected with the first automatic transmission (2) for outputting power to two wheels of the vehicle. The second drive assembly (102) includes a second automatic transmission (2000) and a second motor (1000) connected with the second automatic transmission (2000) for outputting power to the other two wheels of the vehicle. The first and second automatic transmission are configured to be shifted to a preset gear or a gear adjacent to the preset gear, such that when one of the first and second automatic transmission is shifted to the preset gear, the other one of the first and second automatic transmission is shifted to the preset gear or the gear adjacent to the preset gear.

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 control device for a vehicle is provided. The vehicle includes a transmission and an engine configured to input a torque into the transmission. The transmission has multiple transmission stages and includes a first engagement mechanism and a second engagement mechanism. The control device includes an ECU configured to: (a) control the second engagement mechanism when a second transmission stage is set such that the capacity of torque transmission of the second engagement mechanism is increased and a thrust for separating a first member and a second member of the first engagement mechanism from each other in an axial direction is generated; (b) calculate a decrement in an output torque of the transmission when the capacity of torque transmission of the second engagement mechanism is increased; and (c) increase a torque input into the transmission by the engine based on the decrement in the output torque by controlling the engine.

A transmission for a vehicle may include an input shaft connected to a power source, an output shaft disposed in parallel with the input shaft, a synchromesh type shift mechanism including at least two pairs of external gear pairs and a synchronous device which may be installed on the input shaft and the output shaft, and a clutch device provided on a power transfer path connected from the input shaft to the output shaft through the external gear pair and configured to connect the synchronous device in parallel with the power transfer path.

A method is provided to control a hybrid powertrain to achieve gear shifts without torque interruption, comprising a gearbox with input shaft and output shafts; a first planetary gear connected to the input shaft and a first main shaft; a second planetary gear connected to the first planetary gear and a second main shaft; first and second electrical machines respectively connected to the first and second planetary gears; a first gear pair and a third gear pair between the first main shaft and a countershaft; and a second gear pair between the second main shaft and the countershaft, which is connected with the output shaft via a fifth gear pair. The method comprises disconnecting the first gear pair; connecting the first planetary gear with the output shaft via a coupling mechanism connecting the first main shaft and output shaft; disconnecting the fifth gear pair; transferring torque generated from the combustion engine from the second planetary gear to the countershaft via the second gear pair; and transferring a torque from the countershaft to the output shaft via the third gear pair.