A hydraulic pressure calculation apparatus is applied to a gear shifting system including a transmission configured to switch between a connected state and a disconnected state of a friction engagement element depending on a hydraulic pressure supplied from a hydraulic circuit, and a hydraulic controller configured to control the hydraulic circuit. The hydraulic pressure calculation apparatus includes a memory and a processor. The memory stores pieces of mapping data of a plurality of phases obtained by dividing a period from a start to an end of switching between the connected state and the disconnected state of the friction engagement element. Each piece of the mapping data defines a mapping. The processor is configured to output, as an output variable, an estimated hydraulic pressure variable indicating an estimated value of an actual hydraulic pressure supplied from the hydraulic circuit to the friction engagement element.

A nonlinear closed-loop control combined with an integral time-delay feedback control is disclosed to adjust a speed ratio of an infinitely variable transmission (IVT) system. A speed ratio control for an IVT system involves a forward speed controller and a crank length controller for different speed ranges. The time-delay control is designed to reduce speed fluctuations of the output speed of an IVT with an accurate speed ratio. The speed ratio of an IVT with the disclosed control strategy can achieve an excellent tracking response for the desired constant output speed and reduce speed fluctuations of the output speed of an IVT by the time-delay feedback control.

A nonlinear closed-loop control combined with an integral time-delay feedback control is disclosed to adjust a speed ratio of an infinitely variable transmission (IVT) system. A speed ratio control for an IVT system involves a forward speed controller and a crank length controller for different speed ranges. The time-delay control is designed to reduce speed fluctuations of the output speed of an IVT with an accurate speed ratio. The speed ratio of an IVT with the disclosed control strategy can achieve an excellent tracking response for the desired constant output speed and reduce speed fluctuations of the output speed of an IVT by the time-delay feedback control.

A transmission device and method for operating a transmission for a motor vehicle, which transmission device has an input shaft which is operatively connectable to a drive device of the motor vehicle, and has a first output shaft and a second output shaft, and has a spur gear differential transmission configured as a planetary transmission, whereby the input shaft and an intermediate shaft are coupled to the first output shaft and the second output shaft. An electric machine is coupled to the input shaft in a first shifting position of the shifting device and to the intermediate shaft in a second shifting position of the shifting device, and the electric machine is operated for applying a torque to the input shaft.

A transmission device and method for operating a transmission for a motor vehicle, which transmission device has an input shaft which is operatively connectable to a drive device of the motor vehicle, and has a first output shaft and a second output shaft, and has a spur gear differential transmission configured as a planetary transmission, whereby the input shaft and an intermediate shaft are coupled to the first output shaft and the second output shaft. An electric machine is coupled to the input shaft in a first shifting position of the shifting device and to the intermediate shaft in a second shifting position of the shifting device, and the electric machine is operated for applying a torque to the input shaft.

A control device for a continuously variable transmission mounted in a vehicle, includes a lead compensation unit and a delay compensation unit. The lead compensation unit is configured to perform phase lead compensation in a transmission ratio control system of the continuously variable transmission according to an operating state of the vehicle with a lead amount being variable according to a vibration frequency of a torsional vibration of an input shaft of the continuously variable transmission. The delay compensation unit is configured to perform phase delay compensation in the transmission ratio control system with a delay amount being variable according to the operating state of the vehicle.

A vehicle includes a multi-speed transmission having an input shaft and an output shaft, an actuator, and a torque converter having an impeller selectively coupled to the actuator and a turbine coupled to the input shaft. A vehicle controller is programmed to, in response to an estimated torque ratio between the impeller and output shaft of the transmission being less than a minimum torque ratio between the impeller and output shaft of the transmission during a shift of the transmission, command torque to the actuator based on a driver-demanded wheel torque and the minimum torque ratio, and, in response to the estimated torque ratio exceeding the minimum torque ratio during the shift of the transmission, command another torque to the actuator based on the driver-demanded wheel torque and the estimated torque ratio.

A vehicle includes a multi-speed transmission having an input shaft and an output shaft, an actuator, and a torque converter having an impeller selectively coupled to the actuator and a turbine coupled to the input shaft. A vehicle controller is programmed to, in response to an estimated torque ratio between the impeller and output shaft of the transmission being less than a minimum torque ratio between the impeller and output shaft of the transmission during a shift of the transmission, command torque to the actuator based on a driver-demanded wheel torque and the minimum torque ratio, and, in response to the estimated torque ratio exceeding the minimum torque ratio during the shift of the transmission, command another torque to the actuator based on the driver-demanded wheel torque and the estimated torque ratio.

Selection solenoid valve (75) controls engagement/disengagement of travel clutch (31, 32) in synchronization with a selecting operation of selector lever (90) that selects a range position of belt-type continuously variable transmission (CVT). Selection solenoid valve abnormality diagnosing unit (8a) is configured to, when performing a selecting operation from no-drive range to drive range, if a time required for travel clutch (31, 32) to be judged to be engaged from a start of selection of the drive range is less than a predetermined time, judge selection solenoid valve (75) to be a maximum hydraulic pressure side abnormality. When performing the selecting operation of drive range.fwdarw.no-drive range.fwdarw.drive range, if a selecting operation speed condition indicating that a no-drive range selection time is shorter than a setting time (Tth) is satisfied, execution of abnormality diagnosis of selection solenoid valve (75) is not permitted. With this configuration, misjudgment is prevented.

A shift control device for a vehicle includes: an engine; a shift mechanism disposed between the engine and driving wheels; a shift control section configured to control a transmission gear ratio of the shift mechanism; and a fuel cut control section configured to stop a fuel supply to the engine, at least when an accelerator pedal is in a release state, and when an engine speed is equal to or greater than a predetermined rotation speed, the shift control section being configured to perform a minimum rotation speed restriction control to control the transmission gear ratio of the shift mechanism so that the minimum rotation speed of the engine is equal to or greater than the predetermined rotation speed regardless of a vehicle front condition and an accelerator operation condition.