A method to control the execution of a shift to a lower gear while an accelerator pedal is released in a drivetrain provided with a dual-clutch, servo-assisted transmission; the control method comprises the following steps: opening, in a first instant, an outgoing clutch; closing, in the first instant, an incoming clutch; completing the opening of the outgoing clutch and the closing of the incoming clutch in a second instant; synchronizing, between the second instant and a third instant, a rotation speed of the internal combustion engine with a rotation speed of the incoming clutch; and controlling the incoming clutch between the second instant and the third instant so as to have the incoming clutch temporarily transmit a greater torque than the torque that the clutch is going to transmit immediately after the shift to a lower gear and than the torque that the outgoing clutch transmitted immediately before the shift to a lower gear.

A control device and a method for controlling a vehicle powertrain to overcome, or avoid, a cog-to-cog condition during gear shifting is provided. The method comprises, when an input shaft of the gearbox is rotating, controlling a synchromesh arrangement so as to induce a difference in rotational speed between a first gear wheel and a first coupling sleeve arranged to lock the first gear wheel to a main shaft of the gearbox by at least partly engaging the first gear wheel or a second gear wheel to the input shaft. Furthermore, a computer program, a computer-readable medium and a vehicle are provided.

A method to control the execution of a shift to a lower gear while an accelerator pedal is released in a drivetrain provided with a dual-clutch, servo-assisted transmission; the control method comprises the following steps: opening, in a first instant, an outgoing clutch; closing, in the first instant, an incoming clutch; completing the opening of the outgoing clutch and the closing of the incoming clutch in a second instant; synchronizing, between the second instant and a third instant, a rotation speed of the internal combustion engine with a rotation speed of the incoming clutch; and controlling the incoming clutch between the second instant and the third instant so as to have the incoming clutch temporarily transmit a greater torque than the torque that the clutch is going to transmit immediately after the shift to a lower gear and than the torque that the outgoing clutch transmitted immediately before the shift to a lower gear.

Systems and methods are provided for simulating rev-matching in hybrid electric vehicles (HEVs), e.g., HEVs having a two motor hybrid system transmission. In particular, increased engine response is provided while downshifting during acceleration. The two-motor hybrid system transmission may include an electronic control unit that controls the speed of the engine to simulate gears, and increases the speed of the engine responsive to a driver using the gear selector to shift from one of the simulated gears to a lower one of the simulated gears, thereby providing the desired rev-matching experience.

A method for operating a transmission for a motor vehicle having an input shaft, a first shaft connectable to the input shaft via a first input clutch and a second shaft connectable to the input shaft via a second input clutch, a plurality of gearshift clutches, and an output shaft. Different gear ratios between the input and output shafts are implementable by selective engagement of the plurality of clutches. A first torque transmission path between the first and second shafts is engageable with a first friction-locking clutch and a second torque transmission path between the first and second shafts is engageable with a second friction-locking clutch. The method includes actuating, at least intermittently during a synchronization phase in an upshift process of the transmission, the first friction-locking clutch to transmit a first torque and the second friction-locking clutch to transmit a second torque.

A method for performing rotational speed synchronisation of a first transmission component having a first initial rotational speed with a second transmission component having a second initial rotational speed, so that they rotate with the same final rotational speed during a gear switch from an initial driving gear to a final driving gear in a stepped gear transmission for a hybrid electric or electric drive train having an electric traction motor. The method including calculating a total frictional work resulting from performing the total rotational speed synchronisation by means of a mechanical synchroniser of the stepped gear transmission only, and if the calculated total frictional work exceeds a maximal frictional work of the mechanical synchroniser, performing the rotational speed synchronisation by means of both the electric traction motor and the mechanical synchroniser.

A method for performing rotational speed synchronisation of a first transmission component having a first initial rotational speed with a second transmission component having a second initial rotational speed, so that they rotate with the same final rotational speed during a gear switch from an initial driving gear to a final driving gear in a stepped gear transmission for a hybrid electric or electric drive train having an electric traction motor. The method including calculating a total frictional work resulting from performing the total rotational speed synchronisation by means of a mechanical synchroniser of the stepped gear transmission only, and if the calculated total frictional work exceeds a maximal frictional work of the mechanical synchroniser, performing the rotational speed synchronisation by means of both the electric traction motor and the mechanical synchroniser.

A compact and fast-shifting two-speed transmission for an electric drive system, such as an electric vehicle, has two synchronized dog clutches. A sliding sleeve for engaging a first and second gear is actuatable using a single actuator. A substantially load-interruption-free shifting is realized via a friction engagement in the synchronization. A drive system having such a two-speed transmission is capable of achieving at least substantially load-interruption-free shifting.

A method for operating a transmission for a motor vehicle having an input shaft, a first shaft connectable to the input shaft via a first input clutch and a second shaft connectable to the input shaft via a second input clutch, a plurality of separating clutches, and an output shaft. Different gear ratios between the input and output shafts are implementable by selective engagement of the plurality of clutches. A first torque transmission path between the first and second shafts is engageable with a first friction-locking clutch and a second torque transmission path between the first and second shafts is engageable with a second friction-locking clutch. The method includes actuating, at least intermittently during a synchronization phase in an upshift process of the transmission, the first friction-locking clutch to transmit a first torque and the second friction-locking clutch to transmit a second torque.

A transmission is between a drive aggregate and a drive output of a vehicle drivetrain and includes a hydrodynamic starting element and a powershiftable main transmission having a plurality of forward gears and at least one reversing gear. The main transmission has frictional shifting elements, where in each gear a first number of shifting elements are closed and a second number of shifting elements are open. A downstream range group is connected downstream from the main transmission and has at least one interlocking shifting element that can be shifted between first a second driving ranges. With the drive aggregate running, the motor vehicle at a standstill or nearly so, and the main transmission in neutral, a shift request to change the downstream range group is received. The shifting elements of a reversing gear are at least partially closed, and the driving range of the downstream range group is then changed.