Systems and methods for controlling transmissions having CVTs are disclosed with multiple modes and gearing arrangements for range enhancements, where embodiments include synchronous shifting to allow the transmission to achieve a continuous range of transmission ratios, while minimizing empty cycling of the CVT during mode shifts. Embodiments provide for wide ratio range and performance and efficiency flexibility, while maximizing CVT usage through synchronous shifting.

Embodiments of the present invention provide a vehicle drivetrain assembly operable in a first mode and a second mode. The vehicle drivetrain assembly comprises: a drive unit arranged to generate power to drive a vehicle (1); an automatic transmission comprising a torque converter and operatively coupled to the drive unit to receive the power; and a control system comprising one or more controllers (11), the control system being arranged to adjustably limit the maximum torque delivered to the transmission from the drive unit. When the automatic transmission is in first gear with the torque converter stalled, the control system limits the maximum torque to a first level when the vehicle drivetrain assembly is in the first mode and to a second level when the vehicle drivetrain assembly is in the second mode, the first level being lower than the second level.

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 control device for hybrid vehicle is configured to transmit a torque generated by an engine and a motor to a power transmission member according to a driving power request from a driver. The control device for hybrid vehicle includes motor control means and transmission capacity control means. The motor control means is configured to control an output from the motor according to the driving power request. The transmission capacity control means is configured to control a transmission capacity of the power transmission member. The transmission capacity control means is configured to increase the transmission capacity in consideration of a variation of the output from the motor when the output from the motor is increased based on the driving power request. The motor control means is configured to increase the output from the motor after the transmission capacity is increased in consideration of the variation of the output from the motor when the output from the motor is increased based on the driving power request.

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 method for estimating torque transmitted to a structure located downstream of a transmission system of a vehicle is disclosed. The vehicle comprises an engine for generating torque, a transmission system configured to transmit a fraction of the torque generated by the engine to a plurality of wheels of the vehicle, and a further fraction of the torque generated by the engine to the structure. The transmission system includes a shaft arrangement interposed between the engine and the structure, a planetary gearing supported by the shaft arrangement, and a transmission unit arranged in parallel to the shaft arrangement. The torque transmitted to the structure is estimated on the basis of a group of parameters which comprise torque upstream of the transmission system, twist of the shaft arrangement, and a parameter which is indicative of the ratio between an output rotational speed at an output of the transmission unit and an input rotational speed at an input of the transmission unit.

A system and method for controlling a transmission system is provided. One agricultural vehicle includes a vehicle controller configured to instruct an engine controller to maintain an engine at a constant speed and to receive a first signal from a transmission controller indicative of gear shift initiation. The vehicle controller is also configured to instruct the engine controller to maintain the engine at a current torque upon receipt of the first signal and to receive a second signal from the transmission controller indicative of gear shift completion. The vehicle controller is configured to instruct the engine controller to maintain the engine at the constant speed upon receipt of the second signal.

A method for controlling a hybrid drive system for a motor vehicle involves, in an operation in which both the internal combustion engine and the electric machine introduce drive torques into the hybrid gearbox to drive the drive wheel, employing third limit torques for the third gearbox gear are provided in a first mode, and second limit torques for the second gearbox gear are provided in a second mode. A maximum third limit torque of the first mode is greater than a maximum second limit torque of the second mode.

A method and an apparatus for controlling engine start for a hybrid electric vehicle are provided. The apparatus includes a data detector that is configured to detect data for controlling start of an engine. Additionally, a controller is configured to calculate a demand power of a driver based on the data and start the engine when the demand power of the driver is greater than an engine-on power line which is a reference for starting the engine.

A vehicle control device has a controller configured to control a hydraulic pressure required for shifting of a sub-transmission based on an input torque to the sub-transmission during the coordinated shift, and to execute limitation processing in which, when an instruction to execute specific control causing fluctuation in the input torque to the sub-transmission during the coordinated shift is issued, execution of the specific control is prohibited or the specific control is executed by limiting a control amount.