While a vehicle is traveling in a state where any one of gear positions of a mechanical stepped transmission unit is established, until an estimated input torque that is obtained from the equation of motion for an electrical differential unit changes, a hydraulic pressure of a non-engaged intended hydraulic friction engagement device is increased, and a pack end pressure is learned on the basis of the hydraulic pressure at that time. Therefore, irrespective of feedback control, or the like, over motor generators of the electrical differential unit, it is possible to appropriately learn the pack end pressure, so it is possible to appropriately execute hydraulic control over the hydraulic friction engagement devices, that is, engaging and releasing control, or the like, at the time of shifting, irrespective of individual differences of the portions, aging of friction materials, or the like.

While a vehicle is traveling in a state where any one of gear positions of a mechanical stepped transmission unit is established, until an estimated input torque that is obtained from the equation of motion for an electrical differential unit changes, a hydraulic pressure of a non-engaged intended hydraulic friction engagement device is increased, and a pack end pressure is learned on the basis of the hydraulic pressure at that time. Therefore, irrespective of feedback control, or the like, over motor generators of the electrical differential unit, it is possible to appropriately learn the pack end pressure, so it is possible to appropriately execute hydraulic control over the hydraulic friction engagement devices, that is, engaging and releasing control, or the like, at the time of shifting, irrespective of individual differences of the portions, aging of friction materials, or the like.

A powertrain assembly includes a continuously variable transmission having a variator, an input member, an output member and a torque converter clutch. An input sensor configured to receive a signal from the input member. An output sensor is configured to receive a signal from the output member. The assembly includes a controller having a processor and tangible, non-transitory memory on which is recorded instructions for executing a method of controlling the continuously variable transmission. If the torque converter clutch is locked, the controller is programmed to obtain respective readings at predefined time intervals which are collected for the respective signals from the input sensor and the output sensor, until a predefined time window is reached. First and second fast Fourier transforms are obtained of the respective signals. The continuously variable transmission is controlled based at least partially on the first and second fast Fourier transforms.

A hydro-mechanical series and parallel transmission device and a control method thereof are provided. The device includes an input shaft assembly, a hydraulic transmission assembly, a planetary gear transmission assembly, an intermediate gear transmission assembly, and an output shaft assembly. Switching among a hydraulic transmission mode, a mechanical transmission mode, and a hydro-mechanical composite transmission mode is implemented through combination and engagement/disengagement of clutches and brakes. The hydro-mechanical series transmission is used to expand the speed regulation range of the hydraulic transmission and is combined with the hydraulic transmission to meet the requirements on precision and the speed regulation range. The requirements of low-power and high-power operations are met through combination of the hydro-mechanical series and parallel transmissions. Multiple transmission modes are formed to adapt to the working conditions of startup, operation, and transfer.

Systems and methods for operating a transmission of a hybrid powertrain that includes a motor/generator are described. The systems and methods may adjust one or more actuators in response to an estimated transmission input shaft speed that is determined from transmission output shaft speed. The one or more actuators may include a transmission clutch, the motor/generator, or a gear selection solenoid.

A method of controlling a transmission includes detecting a first inflection point and a second inflection point in the movement of the accelerator pedal. An amplitude between the first inflection point and the second inflection point is then calculated, and a period of time between the first inflection point and the second inflection point is measured. An attenuation coefficient is defined from the amplitude and the measured period of time between the first and second inflection points. A current iteration temporary gear ratio is defined as the gear ratio calculated during the most recent iteration of an iterative gear ratio selection algorithm, and is adjusted with the defined attenuation coefficient to define a current iteration final output gear ratio. The operation of the transmission is then controlled to change the transmission from a previous iteration final output gear ratio to the current iteration final output gear ratio.

A vehicle powertrain shift control method includes a step of determining which of four types of divided hydraulic pressure difference areas a main hydraulic pressure difference belongs, by a controller, the main hydraulic pressure difference being a value obtained by subtracting a coupling-side preparatory hydraulic pressure from a coupling-side preliminary target pressure, and a step of limiting the inclination of the control hydraulic pressure corrected calculated value of a first shift initiation phase or a second shift initiation phase so as not to deviate from predetermined limit values, by the controller, when corresponding to an area in which the main hydraulic pressure difference is equal to/less than a predetermined positive first reference value, and an area in which the main hydraulic pressure difference is equal to/larger than a predetermined negative second reference value, respectively, among the four types of hydraulic pressure difference areas.

A method of controlling a transmission includes detecting a first inflection point and a second inflection point in the movement of the accelerator pedal. An amplitude between the first inflection point and the second inflection point is then calculated, and a period of time between the first inflection point and the second inflection point is measured. An attenuation coefficient is defined from the amplitude and the measured period of time between the first and second inflection points. A current iteration temporary gear ratio is defined as the gear ratio calculated during the most recent iteration of an iterative gear ratio selection algorithm, and is adjusted with the defined attenuation coefficient to define a current iteration final output gear ratio. The operation of the transmission is then controlled to change the transmission from a previous iteration final output gear ratio to the current iteration final output gear ratio.

A vehicle includes a system and method of operating a gearbox of the vehicle. The vehicle includes an interface for entering a desired vehicle acceleration and a processor. The system includes a processor. The processor is configured to receive the desired vehicle acceleration, create an objective function that relates the desired vehicle acceleration to a torque, perform an optimization process on the objective function to determine the torque, and apply the torque to the vehicle to achieve the desired vehicle acceleration.