The present invention provides a hybrid powertrain comprising an internal combustion engine (ICE), a transmission (2), a first electric motor (4a) and a second electric motor (4b), wherein the transmission comprises an input shaft (1) to which the ICE is connected via a main clutch (3), an output shaft (6) and a gear assembly providing at least two different gear ratios that may be selected for transfer of mechanical power from the input shaft (1) to the output shaft (6), the first electric motor (4a) is connected to the input shaft (1) via a first gear (i.sub.x), such that torque and rotation may be transferred between the first electric motor and the input shaft, and the second electric motor (4b) is connected to the input shaft (1) via a first clutch (5a) and the first gear (i.sub.x), such that torque and rotation may be transferred between the second electric motor (4b) and the input shaft (1), and connected to the output shaft (6) via a second clutch (5b) and a second gear (i.sub.y), such that torque and rotation may be transferred between the second electric motor (4b) and the output shaft (6), wherein the first electric motor (4a) is connected to the second electric motor (4b) via the first clutch (5a), and the first electric motor (4a), the second electric motor (4b), the first clutch (5a) and the second clutch (5b) form parts of a torque transfer path bypassing the at least two different gear ratios, the torque transfer path arranged to transfer torque from the input shaft (1) to the output shaft (6) during a gearshift.

A method of controlling a vehicle drivetrain by an electric motor, in order to synchronize the speed of an internal combustion engine and the speed of gears in the drivetrain, wherein if a speed synchronization error e.sub.sync(t) is controlled to remain within a prespecified region for a specific period of time, the synchronization is finished, and a gear may be engaged.

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.

A method of shifting a vehicle transmission including a first clutching device and a second clutching device is described. At least a portion of the first clutching device is coupled with or configured to be coupled with at least a portion of the second clutching device. The method may include the steps of engaging the second clutching device, where engaging the second clutching device includes controlling a state of the second clutching device by changing a state of the first clutching device. A transmission controller and a vehicle driveline are also described.

A shift control method for the vehicle with a DCT may include a start determining step of determining, by a TCU, whether the DCT may have entered a power-on down shift inertia phase, a clutch control step of controlling a release-side clutch by determining, by the TCU, a release-side clutch control torque, when the DCT enters the power-on down shift inertia phase, a limit determining step of determining whether the release-side clutch control torque is reduced below a predetermined minimum control torque, while the TCU performs the clutch control step, and an engine-assistance requesting step of requesting an ECU to set an engine-torque rise request amount in proportion to a release-side clutch control torque reduction amount that is additionally required by the TCU, when it is determined in the limit determining step that the release-side clutch control torque is reduced below the minimum control torque.

There are provided a transmission control device and a transmission control method that controls a prime mover in a system including the prime mover and a gear transmission. A processing circuitry of the transmission control device executes a process including: determining whether to fall into a predetermined situation at a time of acquiring a shift command; when it is determined as being the predetermined situation, starting a separation control that adjusts an output of the prime mover such that a dog is separated from an abutment surface against which the dog abuts at the time of acquiring the shift command; and after the separation control is completed and before the dog at the first transmission gear position moves out of an accommodation space at the first transmission gear position, starting a synchronous control relating to the dog and transmission gears.

A method of operating a transmission which is shifted to various operating conditions by engaging shifting elements. At least one of the shifting elements is an interlocking shifting element which has to be engaged to obtain at least one defined operating condition of the transmission during which force flows between an input and an output shaft. When a command is received to engage the interlocking shifting element, a rotational speed of the transmission input shaft is displaced in the direction toward a synchronous rotational speed produced in the engaged operating condition of the interlocking shifting element at least as a function of the rotational speed of the transmission output shaft. When the variation of the rotational speed of the transmission input shaft crosses a predefined rotational speed threshold, the interlocking shifting element is actuated in its engaging direction.

The present invention provides a shift control method implemented in a vehicle equipped with an automatic transmission for controlling an input shaft rotation speed to a target input shaft rotation speed during a shift. The method includes setting of a basic target synchronization rotation speed that is a basic target value of the input shaft rotation speed during the shift, and setting of a corrected target input shaft rotation speed as the target input shaft rotation speed when the shift is a downshift without a requirement for a driving force of the vehicle, The corrected target input shaft rotation speed is obtained by decreasingly correcting the basic target synchronization rotation speed. Further, a decreasing correction amount of the basic target synchronization rotation speed is set so as to become larger as a deceleration of the vehicle becomes larger.

A method of controlling a drive axle system. The method may include executing a gear upshift or a gear downshift after decreasing the torque that is provided by an electric motor to a transmission of an axle assembly and increasing the torque that is provided by another electric motor to a transmission of another axle assembly.

There is provided a transmission control device that controls a first prime mover and a second prime mover of which output responsiveness is different from each other. A processing circuitry of the transmission control device executes a process including: in response to a shift command, calculating each target rotational speed of the first prime mover and the second prime mover for a synchronous control that brings one of rotational speeds of a dog and a transmission gear at the second transmission gear position close to the other; and determining a first timing or a second timing such that the second timing is later than the first timing, the first timing being a time at which the synchronous control of the first prime mover is started, and the second timing being a time at which the synchronous control of the second prime mover is started.