A power transmission system of a hybrid electric vehicle uses an engine and a motor/generator as power sources, and includes: a torque converter including a planetary gear set having first, second, and third rotating elements, the first rotating element being selectively connected to a transmission housing, the second rotating element being connected to an engine output shaft of the engine, and the third rotating element being connected to a motor output shaft of the motor/generator; an input device including a first input shaft selectively connected to the motor output shaft through one clutch and a second input shaft that is disposed on a same shaft line as the first input shaft to be selectively connected to the motor output shaft through another clutch; and a shift output device shifting and outputting rotation power of the input device.

A control device of a vehicle including a multi-speed transmission having gear positions switched by executing release of a release-side engagement device out of a plurality of engagement devices and engagement of an engagement-side engagement device out of the plurality of engagement devices, and an engine of which a power is transmitted through the multi-speed transmission to drive wheels, the control device performing a shift of the multi-speed transmission by using a predefined shift model for determining control operation amounts of a torque at an input rotating member of the multi-speed transmission, a torque capacity of the release-side engagement device, and a torque capacity of the engagement-side engagement device, the control operation amounts achieving shift target values that are a target value of a torque at an output rotating member of the multi-speed transmission and a target value of angular acceleration of the input rotating member of the multi-speed transmission, the control device comprising: a condition setting portion setting a condition necessary for determining the control operation amounts using the shift model such that during a downshift performed during deceleration running associated with accelerator-off state, an output torque of the engine is raised with the release-side engagement device released so as to increase a rotation speed of the input rotating member of the multi-speed transmission toward a synchronous rotation speed after the downshift and such that the engagement-side engagement device is then engaged; and a shift target value setting portion setting the target value of the torque at the output rotating member of the multi-speed transmission during the downshift such that the torque at the output rotating member of the multi-speed transmission is increased from a value of the torque at the output rotating member before the downshift within a range of zero or less, and when a rotation speed of the input rotating member of the multi-speed transmission approaches the synchronous rotation speed after the downshift, the target value is reduced toward a torque at the output rotating member after the downshift.

A method for operating a transmission, wherein the transmission is shifted from an original gear to a target gear, the method including: setting one of the shift elements located in a power flow of the transmission essentially load-free by use of an electric motor; opening the shift element essentially load-free in the first step; synchronizing a rotational speed between two shafts of the transmission by the electric motor or by a torque at the transmission input shaft, the two shafts to be connected in the target gear through a shift element not in the power flow of the transmission at the first step; and locking the shift element between the two shafts synchronized in the third step; wherein a change to a transmission ratio between the original gear and the target gear is greater than a change between the original gear and an adjacent gear.

An automatic transmission and a method of synchronization are described. The automatic transmission includes a plurality of planetary gear sets, a plurality of dog clutches and a plurality of brakes coupled to the plurality of planetary gear sets, and an electric machine coupled to the plurality of dog clutches and a plurality of brakes via the planetary gear sets. Further, the automatic transmission includes a first speed sensor measuring a first speed of the electric machine and a second speed sensor measuring a second speed of an output shaft, and a synchronization controller configured to receive the first speed sensor data and the second speed sensor data, determine a synchronization speed, and adjust the first speed of the electric machine to the synchronization speed.

A method for shift control of an automated auxiliary transmission that is mounted in a drive train of a motor vehicle between a drive motor (AM) and a final drive, and includes at least one multi-step main gearing (HG) and one two-step front-mounted group (VG) connected upstream of the main gearing (HG), and with which the main gearing (HG) can be shifted via unsynchronized clutches and the front-mounted group can be shifted via synchronized clutches. Depending on the currently existing driving or operating situation, a gear change is performed in the auxiliary transmission through a change in the transmission ratio step (G1, G2, G3) of the main gearing (HG) while maintaining the currently engaged transmission ratio step (K1, K2) in the front-mounted group (VG).

A method of controlling an electric vehicle transmission includes: a torque-securing step of securing a predetermined spare torque to be generated by a motor in accordance with a current motor torque when a controller determines that there is a need for downshift from an upper gear step to a lower gear step; a slip-controlling step of generating a friction force through a servo clutch applying a friction force between an input shaft and a servo driving gear of a pair of servo gears; a shifting-to-neutral step of shifting to a neutral gear by disengaging a synchronizer for the upper gear step; a motor-synchronizing step of synchronizing a rotational speed of the motor with a desired speed of a lower gear step using the spare torque of the motor secured in the torque-securing step; a gear-engaging step of engaging a synchronizer for the lower gear step; and a clutch-disengaging step of finishing shifting by disengaging the servo clutch.

Provided are gearboxes including compound planet gear assemblies as well as methods of using such gearboxes. A gearbox includes at least a first ring gear and a second ring gear. Depending on the current gear selection, one of these ring gears may be engaged with a shifting mechanism or not engaged with any ring gears when in a neutral gear. The first ring gear may be constantly engaged with a first planet gear of a compound planet gear assembly, while the second ring gear may be constantly engaged with a second planet gear of the same compound planet gear assembly. The first planet gear may be also engaged with a sun gear coupled to a shaft. Another shaft is coupled to the shifting mechanism. Different gear selections of the gearbox engage different ring gears to the shifting mechanism thereby changing the rotational speed ratio of the two shafts.

A power transmission system of a hybrid electric vehicle uses an engine and a motor/generator as power sources, and includes: a torque converter including a planetary gear set having first, second, and third rotating elements, the first rotating element being selectively connected to a transmission housing, the second rotating element being connected to an engine output shaft of the engine, and the third rotating element being connected to a motor output shaft of the motor/generator; an input device including a first input shaft selectively connected to the motor output shaft through one clutch and a second input shaft that is disposed on a same shaft line as the first input shaft to be selectively connected to the motor output shaft through another clutch; and a shift output device shifting and outputting rotation power of the input device.

An electric motorcycle includes an electric motor, a manual transmission, a shift drum potentiometer, and an ECU. When it is determined based on an input from the shift drum potentiometer that a transmission manipulation has been performed, the ECU executes a first control operation when switching from a power transmission state to a power cut state and executes a second control operation when returning from the power cut state to the power transmission state. In the first control operation, the ECU controls an operation of the electric motor to facilitate disengagement of an engagement mechanism from a gear train of the manual transmission. In the second control operation, for facilitating engagement of the engagement mechanism with a different gear train, the ECU controls the operation of the electric motor to make a revolving speed of the different gear train close to the revolving speed of the engagement mechanism.

An automatic transmission control device with which it is occurrence of meshing failure at the time of engaging an engagement clutch may be prevented while suppressing prolonged time for completing the engagement. Disclosed is an automatic transmission control device comprising: an automatic transmission that is provided in the drive system of a vehicle and that includes, as an coupling element, an engagement clutch which undergoes meshing/engagement at the time of coupling; and a transmission controller that performs transmission control of the automatic transmission. The engagement clutch includes: a clutch gear connected to a transmission input shaft; and a clutch hub connected to a transmission output shaft and capable of meshing with the clutch gear. At the time of shifting at which the engagement clutch is engaged, the transmission controller sets a target differential rotation speed for generating a predetermined differential rotation between the input rotation speed and the output rotation speed in the engagement clutch when the clutch gear and the clutch hub mesh with each other.