A method for turning off an internal combustion engine (ICE) where a clutch arrangement has first and second clutches that respectively couple the ICE to first and second input shafts of a transmission. The input shafts are drivingly connected to first and second sets of gears, respectively. The sets of gears are connected to an output shaft of the transmission. The method includes: controlling the ICE in an idling state when the vehicle is in standstill, wherein the clutches are in open positions; engaging the first input shaft with a first pre-selected gear, and engaging the second input shaft with a second pre-selected gear; initiating an engine turning off command; stopping the ICE by at least partly closing the clutches for simultaneously introducing torque transfer to the clutches into a transmission tie-up state for a controlled engine stop, wherein engine inertia of the ICE is captured in the clutches.

A method for operating a dual clutch transmission of a motor vehicle having a first partial transmission, a second partial transmission, and a transmission output shaft common to the partial transmissions and drivable both by the first partial transmission and by the second partial transmission, in which the dual clutch transmission is in a parking lock state in which two gears of one of the partial transmissions are engaged simultaneously. The following steps are carried out to exit the parking lock state: Introducing a torque caused by a drive element of the motor vehicle via the transmission output shaft common to the one partial transmissions into the one and/or other partial transmission while the gears of the partial transmission are engaged; and disengaging at least one of the gears of the one partial transmission engaged simultaneously in step a).

A method for operating a dual clutch transmission of a motor vehicle having a first partial transmission, a second partial transmission, and a transmission output shaft common to the partial transmissions and drivable both by the first partial transmission and by the second partial transmission, in which the dual clutch transmission is in a parking lock state in which two gears of one of the partial transmissions are engaged simultaneously. The following steps are carried out to exit the parking lock state: Introducing a torque caused by a drive element of the motor vehicle via the transmission output shaft common to the one partial transmissions into the one and/or other partial transmission while the gears of the partial transmission are engaged; and disengaging at least one of the gears of the one partial transmission engaged simultaneously in step a).

A hybrid drive includes a control unit, an internal combustion engine, an electrical machine and a dual clutch transmission having an output shaft. The dual clutch transmission includes a first sub-transmission and a second sub-transmission, each couplable to the output shaft. A drive shaft of the internal combustion engine is couplable to a first input shaft of the first sub-transmission via a first clutch and to a second input shaft of the second sub-transmission via a second clutch. The control unit is configured to permit the second clutch to be closed even when the hybrid drive is being operated purely electrically so that the driveshaft of the internal combustion engine is driven by the electrical machine. A control unit and a method for operation of a hybrid drive are also provided.

A hybrid drive includes a control unit, an internal combustion engine, an electrical machine and a dual clutch transmission having an output shaft. The dual clutch transmission includes a first sub-transmission and a second sub-transmission, each couplable to the output shaft. A drive shaft of the internal combustion engine is couplable to a first input shaft of the first sub-transmission via a first clutch and to a second input shaft of the second sub-transmission via a second clutch. The control unit is configured to permit the second clutch to be closed even when the hybrid drive is being operated purely electrically so that the driveshaft of the internal combustion engine is driven by the electrical machine. A control unit and a method for operation of a hybrid drive are also provided.

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.

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.

The invention relates to a multi-speed transmission (10, 110), comprising a power split device (11; 111), an input shaft (12, 112) of the transmission (10, 110) being connected or connectable to prime mover (18, 118), an output shaft (13; 113), two shiftable sub-transmissions (14, 114; 15, 115), each providing a plurality of different gear ratios, and at least one rotating electric machine (16; 116, 116a), connected to said power split device (11; 111), wherein the two sub-transmissions (14, 114; 15, 115) can be connected alternatively to the output shaft (13, 113), and a control system (26; 126, 126a), connecting said electric machine (16; 116, 116a) with an electric battery (27; 127) and auxiliary electrical consumers (31, 131). The electric machine (16; 116, 116a) is connected to the power split device (11; 111) in a way that it allows to reduce torque value down to zero on either an input shaft (20; 120) of the first sub-transmission (14; 114) or on an input shaft (22; 122) of the second sub-transmission (15; 115) by applying different shaft torque levels, and the internal heat generation capacity of the electric machine (16; 116, 116a) exceeds the power capacity of the power line in said control system (26; 126, 126a).

A shifting control method for a hybrid vehicle may include motor torque determination step, of determining the condition of a motor torque, by a controller, in a power-off downshift shifting process, gear mesh step, by the controller, of releasing a clutch of a releasing side and meshing a target shifting stage gear connected to a clutch of engaging side when the motor torque is positive (+) torque, an assist control step, of controlling, by the controller, the motor torque to 0 Nm, a rising step, by the controller, of controlling the motor speed to rise and follow a target motor speed predetermined higher than at least an input shaft speed of an engaging side after releasing the assist control, and an engaging step, by the controller, of engaging the clutch of the engaging side by a clutch torque of the engaging side when the motor speed exceeds the input shaft speed of the engaging side.

A shifting control method for a hybrid vehicle may include motor torque determination step, of determining the condition of a motor torque, by a controller, in a power-off downshift shifting process, gear mesh step, by the controller, of releasing a clutch of a releasing side and meshing a target shifting stage gear connected to a clutch of engaging side when the motor torque is positive (+) torque, an assist control step, of controlling, by the controller, the motor torque to 0 Nm, a rising step, by the controller, of controlling the motor speed to rise and follow a target motor speed predetermined higher than at least an input shaft speed of an engaging side after releasing the assist control, and an engaging step, by the controller, of engaging the clutch of the engaging side by a clutch torque of the engaging side when the motor speed exceeds the input shaft speed of the engaging side.