A method for operating a vehicle drive train (1) includes, during a downshift, disengaging at least one shift element (A through F) from a power flow of the transmission (5), guiding a power transmission capacity of a torque converter lockup clutch (4) to a level at which the torque converter lockup clutch (4) is in a non-slip operating condition during a positive engine override when a rotational speed of a prime mover (2) is guided towards a synchronous speed of a demanded desired ratio, and guiding the power transmission capacity of the torque converter lockup clutch (4)—no later than a point in time of the downshift at which the rotational speed of the prime mover (2) is equal to the synchronous speed of the desired ratio—to a level at which the torque converter lockup clutch (4) is transferred into a continuous slip operation due to torque.

A multiple speed transmission includes an input shaft, an output shaft, a first planetary gearset having a first member, a second member, and a third member, and a second planetary gearset having a first member, a reaction member, a second member, and a third member. The transmission also includes a plurality of interconnecting members each connected between at least one of the first and second planetary gearsets and at least another of the first and second planetary gearsets. The transmission includes a plurality of torque-transmitting mechanisms which are selectively engageable in combinations of at least two to establish between seven and nine forward speed ratios and between two and four reverse speed ratios between the input shaft and the output shaft.

An electro-hydraulic control system for a multispeed transmission having a plurality of torque-transmitting mechanisms includes a controller for operably controlling the transmission, a fluid source for supplying hydraulic fluid, and a plurality of torque-transmitting mechanisms being operably selected between an applied and an unapplied state to achieve a plurality of ranges including at least one reverse, a neutral, and a plurality of forward ranges. The system includes a plurality of trim systems having pressure control solenoids and trim valves. The system may also include one or more shift valves disposed in fluid communication with the fluid source and being capable of moving between stroked and de-stroked positions. In any given range, only two of the plurality of torque-transmitting mechanisms may be applied. Moreover, three of the plurality of pressure control solenoids are normally high solenoids, and the remaining solenoids are normally low solenoids.

A power transmission apparatus configured for a vehicle, may include a first input shaft selectively connectable to an engine output shaft, a second input shaft mounted coaxial with the first input shaft and selectively connectable to the engine output shaft, a third input shaft external to the second input shaft and selectively connectable to the engine output shaft, a torque mediating shaft mounted coaxial with the first input shaft, first and second intermediate shafts, an idle shaft, a first shifting section including five gear sets, the first and second intermediate shafts, the torque mediating shaft and the idle shaft, a second shifting section including a planetary gear set having a sun gear fixedly connected to the torque mediating shaft, and an output shaft mounted coaxial with and selectively connectable to the first intermediate shaft and outputting a torque from the first and second shifting sections.

An electro-hydraulic control system for a multispeed transmission having a plurality of torque-transmitting mechanisms includes a controller for operably controlling the transmission, a fluid source for supplying hydraulic fluid, and a plurality of torque-transmitting mechanisms being operably selected between an applied and an unapplied state to achieve a plurality of ranges including at least one reverse, a neutral, and a plurality of forward ranges. The system includes a plurality of trim systems having pressure control solenoids and trim valves. The system may also include one or more shift valves disposed in fluid communication with the fluid source and being capable of moving between stroked and de-stroked positions. In any given range, only two of the plurality of torque-transmitting mechanisms may be applied. Moreover, three of the plurality of pressure control solenoids are normally high solenoids, and the remaining solenoids are normally low solenoids.

A control device for an automatic transmission includes a traveling drive source, an automatic transmission, an AT controller, and a traveling drive source controller. The AT controller is configured to execute shifting by changeover of friction elements upon receiving a shift request. The traveling drive source controller is configured to execute torque limit control of the traveling drive source when a request for limiting a torque by an upper limit torque is input from the AT controller. The AT controller has an upper limit torque change processing unit configured to change the upper limit torque from a low gear upper limit torque to a high gear upper limit torque when auto-upshift is executed. The upper limit torque change processing unit is configured to raise the upper limit torque using a prescribed gradient during an inertia phase when the inertia phase is started with the auto-upshift.

A method for operating a transmission (3) that includes at least one form-locking shift element (A, F) with two shift-element halves is provided. The shift element (A, F) is disengaged in a first end position and is engaged in a second end position of a displaceable shift-element half. Upon detection of a sensor malfunction, a check is carried out to determine whether the shift-element half, before the malfunction of the sensor, was in an end position as demanded and was actuated by an actuation force acting in the direction of this end position. Power flow in the transmission (3) is maintained for as long as it takes for the shift-element half, starting from the current end position, to be actuated in the direction of the other end position and/or for the actuation force acting in the direction of the current end position to be less than a threshold value.

A dual-clutch transmission may include: a first input shaft and a second input shaft mounted concentrically to the first input shaft; a first clutch mounted to the first input shaft to selectively transmit power to the first input shaft; a second clutch mounted to the second input shaft to selectively transmit power to the second input shaft; a first output shaft and a second output shaft mounted in parallel with the first input shaft and the second input shaft; an input shaft connection device provided to switch a power transmitting and a blocking state between the first input shaft and the second input shaft by use of a selection output shaft; a plurality of drive gears mounted on the first input shaft and the second input shaft; and a plurality of driven gears mounted on the first output shaft and the second output shaft engaged with the plurality of drive gears to form each shifting stage.

A power transmission apparatus of a hybrid electric vehicle includes a first input shaft mounted along an axis of an engine shaft and selectively connectable to the engine shaft, a second input shaft formed as a hollow shaft, coaxially mounted with the first input shaft, and fixedly connected to a rotor of the first motor-generator, a third input shaft formed as a hollow shaft, coaxially mounted with the first input shaft, and selectively connectable to the first input shaft, an intermediate shaft mounted in parallel with the first input shaft, an output shaft mounted in parallel to the first input shaft and outputting a shifted toque, a planetary gear set mounted on the output shaft, having an element fixed to the output shaft and forming a shifted torque, and a plurality of gear sets mounted over the first, second, and third input shafts, the intermediate shaft, and the output shaft.

A power transmission apparatus for a hybrid electric vehicle may include an input shaft receiving an engine torque, first and second planetary gear sets respectively having first to third rotation elements fourth to sixth rotation elements, a first shaft fixedly connected to the first rotation element and the motor-generator and selectively connectable to the input shaft, a second shaft fixedly connected to the second and sixth rotation elements and selectively connectable to the input shaft, a third shaft fixedly connected to the third rotation element and selectively connectable to the transmission housing, a fourth shaft fixedly connected to the fourth rotation element and selectively connectable to the transmission housing, a fifth shaft fixedly connecting the fifth rotation element and an output gear and selectively connectable to the third shaft, and a plurality of engagement elements including at least one clutch and at least one brake.