Methods and systems for a hydromechanical transmission. In one example, the transmission system includes a hydrostatic assembly including a variable displacement hydraulic pump and a hydraulic motor and a planetary gearset coupled to a multi-speed gearbox, a hydraulic motor, and an output shaft via separate gears and shafts. In the system the variable displacement hydraulic pump is coupled to an input of the multi-speed gearbox, the multi-speed gearbox includes one or more clutches and is coupled to a prime mover and the output shaft is designed to couple to an axle.

A drive unit includes an electric motor, first and second torque transmission paths, a torque converter, first and second gear trains, and a first switch mechanism. The first and second torque transmission paths are provided parallel to each other. The torque converter is disposed in the first torque transmission path. The torque converter amplifies a torque outputted from the motor when the torque is directed in a first rotational direction. The first gear train is disposed in the first torque transmission path. The first gear train is disposed downstream with respect to the torque converter. The second gear train is disposed in the second torque transmission path. The first switch mechanism switches between the first torque transmission path and the second torque transmission path as a path for transmitting the torque outputted from the motor.

A multi-speed transmission including a plurality of planetary gearsets and a plurality of selective couplers to achieve at least eighteen forward speed ratios and at least two reverse speed ratios is disclosed. The plurality of planetary gearsets may include a first planetary gearset, a second planetary gearset, a third planetary gearset, a fourth planetary gearset, and a fifth planetary gearset. The plurality of selective couplers may include a number of clutches and a number of brakes. The multi-speed transmission may have five planetary gearsets and eight selective couplers. The eight selective couplers may include three clutches and five brakes.

Methods and systems for transmission control are provided. In one example, a transmission system operating method includes maintaining a displacement set-point of a variable displacement hydraulic motor in a hydrostatic assembly within a working zone, where at least a portion of a boundary of the working zone is determined based on a kinematic constraint of the hydrostatic assembly. the transmission system includes the hydrostatic assembly that includes the variable displacement hydraulic motor that is hydraulically coupled in parallel with a variable displacement hydraulic pump and a gearbox mechanically coupled to the hydrostatic assembly and including one or more clutches.

Provided is an electrified vehicle including a motor and a transmission, and a control method thereof. The electrified vehicle is caused to travel forward when forward gear is achieved and the electrified vehicle is caused to travel backward when reverse gear is achieved while the motor is performing forward rotation. When the transmission is switched to reverse gear while the electrified vehicle is traveling forward, or when the transmission is switched to forward gear while the electrified vehicle is traveling backward, fail-safe control to allow reverse rotation of the motor is executed, thereby suppressing a great shock from being generated in the vehicle.

A transmission for a vehicle is configured to provide nine forward gears in sequence from the first gear to the ninth gear The transmission includes

a first and a second planetary gear set, wherein

the first and second planetary gear sets are configured axially in series, wherein

each planetary gear set is configured to provide a first and a second forward speed reduction and one direct speed with a one to one (1:1) speed ratio, the first forward speed reduction being larger than the second forward speed reduction, thereby providing three forward speeds with different speed ratios wherein

each planetary gear set is configured to be individually shiftable between its three forward speeds

wherein the transmission is configured to provide

the first to third gears by utilizing the first forward speed reduction of the second planetary gear set and by alternating the three forward speeds with different speed ratios of the first planetary gear set,

the fourth to fifth gears by utilizing the first forward speed reduction of the first planetary gear set,

the sixth to seventh gears by utilizing the second forward speed reduction of the first planetary gear set, and

the eighth to ninth gears by utilizing the direct speed of the first planetary gear set.

A control device with an electronic control unit that is configured to perform specific supply control, the specific supply control driving at least one of the rotating electrical machine and the internal combustion engine in a neutral state, and supplying hydraulic pressure to an engagement operating part of a target engagement device with at least one of the rotating electrical machine and the internal combustion engine being driven, the automatic transmission not transmitting power in the neutral state, and the target engagement device being one of the plurality of transmission engagement devices.

A transmission unit for a hybrid motor vehicle, includes an input shaft that can be connected to an internal combustion engine, a planetary gearing, which can be coupled to the input shaft, the planetary gearing having a first planetary wheel set and a second planetary wheel set, a first electric machine the rotor of which is rotationally fixedly coupled to the input shaft, a second electric machine which is coupled with a component part of the planetary gearing, and no more than four switching devices, each of which forms a brake or a clutch, and each can be moved between an activated position and a deactivated position. The switching devices are used for switching various transmission ratios acting between the input shaft and an output shaft and/or between the second electric machine and the output shaft. The no more than four switching devices are configured to implement four different transmission ratios in a drive state of the internal combustion engine, and two different transmission ratios in a drive state of the second electric machine, thereby implementing a serial operation as a result of their activated and deactivated positions. The invention disclosure also relates to a motor vehicle comprising said transmission unit.

A hybrid dual-clutch transmission includes a first sub-transmission and a second sub-transmission, a first countershaft, a first output gear non-rotatably connected to the first countershaft, a second countershaft, a dual clutch, which has a first clutch assigned to the first sub-transmission and a second clutch assigned to the second sub-transmission, a separating clutch and an electric motor. The electric motor is or can be coupled to the separating clutch and to the dual clutch.

A transmission, in particular a reducer transmission (34), which has two planetary sets and two shift elements (S1, S2). In addition, a transmission assembly which has a main transmission (32), of a planetary design, in particular a continuous power split transmission of a planetary design, and such a transmission which is coupled, as a reducer transmission (34), with the main transmission (32). Also, a powertrain (10) of a working machine with such a transmission assembly (30).