A shift control device includes: a stepless shift controller executing a stepless shift mode and controlling a transmission gear ratio of a continuously variable transmission in a stepless fashion; a stepped shift controller executing a stepped shift mode and controlling the continuously variable transmission using fixed transmission gear ratios; a mode setting unit switching the shift mode to the stepped shift mode when a vehicle is to be accelerated; and a transmission-gear-ratio setting unit setting an initial transmission gear ratio in the stepped shift mode when the shift mode is to be switched to the stepped shift mode. The transmission-gear-ratio setting unit estimates a variation in an engine rotation speed when the shift mode is to be switched to the stepped shift mode, and sets a fixed transmission gear ratio, at which the variation is greater than or equal to a lower limit value, as the initial transmission gear ratio.

A shift control device of a vehicle including an internal combustion engine and a multi-speed transmission in series, the shift control device comprises: a control portion providing a downshift control in which an input shaft rotation speed of the multi-speed transmission is increased through a torque-up of the internal combustion engine toward a post-shift input shaft rotation speed in a neutral state where a release-side engagement device to be released during a downshift of the multi-speed transmission is released, so as to engage an engagement-side engagement device to be engaged after the shift. In the case of a shift pattern having a large internal inertia of the multi-speed transmission, the control portion controls a torque capacity of the engagement-side engagement device to a value greater than zero before starting a torque-up control of the internal combustion engine.

A device and a method of controlling a transmission of a vehicle may include a determining device that compares road information related to a first road section corresponding to a road section on which the vehicle is currently traveling and a second road section disposed ahead of the first road section to determine a gradient of the second road section, a calculating device that determines an increase amount of a gradient-inducing resistance based on a difference between gradients of the first road section and the second road section according to a determination result from the determining device, and a controller that compares the increase amount of the gradient-inducing resistance with a reference value to perform transmission control and engine torque control based on comparison of the increase amount of the gradient-inducing resistance with the reference value.

Described herein is a gearbox for a motor vehicle including a plurality of forward gear ratios and a reverse gear ratio, the gearbox further including: a control device (configured for controlling the selection and the engagement of said forward gear ratios and of said reverse gear ratio; and a plurality of engagement devices that can be controlled by means of said control device for engaging the forward gear ratios or reverse gear ratio (RM) of the gearbox that are operatively associated to said devices. The gearbox includes a locking device, which is electrically controlled and configured for preventing actuation of the engagement device associated to a predetermined forward gear ratio, said locking device being configured for being actuated above a threshold speed of the motor vehicle on which said gearbox is installed.

A vehicle control device performing upshift to a forward gear stage in a current travel section in a case where: (1) the forward gear stage is higher than a current gear stage; (2) a travel resistance of a vehicle in the current travel section is greater than a driving force in a case of traveling at the forward gear stage; (3) a stall amount until the vehicle passes an end point of the current travel section in a case where the vehicle travels in the current travel section at the forward gear stage is equal to or smaller than a specified value; and (4) a value obtained by subtracting the travel resistance of the vehicle in a forward travel section from a driving force in a case where the vehicle travels in the forward travel section at the forward gear stage is equal to or greater than a predetermined value.

A method of controlling a multispeed transmission includes providing a transmission controller, a plurality of ranges of the transmission of which at least one of the plurality of ranges is defined as a limiting range, and a communication link. The transmission is operated in a first range of the plurality of ranges and the method includes detecting a loss of communication over the communication link between the transmission controller and another controller. The method also includes determining if the first range is defined as the limiting range when communication is lost and commanding a shift from the first range to a second range of the plurality of ranges which is not defined as the limiting range. The method further includes controlling the shift from the first range to the second range.

A shift control device includes: a stepless shift controller executing a stepless shift mode and controlling a transmission gear ratio of a continuously variable transmission in a stepless fashion; a stepped shift controller executing a stepped shift mode and controlling the continuously variable transmission using fixed transmission gear ratios; a mode setting unit switching the shift mode to the stepped shift mode when a vehicle is to be accelerated; and a transmission-gear-ratio setting unit setting an initial transmission gear ratio in the stepped shift mode when the shift mode is to be switched to the stepped shift mode. The transmission-gear-ratio setting unit estimates a variation in an engine rotation speed when the shift mode is to be switched to the stepped shift mode, and sets a fixed transmission gear ratio, at which the variation is greater than or equal to a lower limit value, as the initial transmission gear ratio.

A method of controlling a multispeed transmission includes providing a transmission controller, a plurality of ranges of the transmission of which at least one of the plurality of ranges is defined as a limiting range, and a communication link. The transmission is operated in a first range of the plurality of ranges and the method includes detecting a loss of communication over the communication link between the transmission controller and another controller. The method also includes determining if the first range is defined as the limiting range when communication is lost and commanding a shift from the first range to a second range of the plurality of ranges which is not defined as the limiting range. The method further includes controlling the shift from the first range to the second range.

This vehicle control device 10 is provided with: a current gear stage selection unit 13 which, on the basis of the travel resistance of the vehicle, selects a current gear stage, which is the gear stage of the vehicle in the current travel segment where the vehicle is traveling; a next gear stage selection unit 16 which selects a next gear stage, which will be the gear stage of the vehicle in the next travel segment, forwards in the travel direction of the vehicle, having a road slope different from that of the current travel segment; and a shift control unit 17 which, if during travel of the vehicle in the current travel segment in the current gear stage, the current gear stage selection unit 13 has newly selected a target gear stage higher than the next gear stage, controls shifting such that upshifting from the current gear stage to the target gear stage is suppressed and the current gear stage is maintained. If, in a state in which upshifting is suppressed, the engine rotation speed reaches or exceeds a prescribed value during travel in the current travel segment, the shift control unit 17 controls shifting so as to upshift to the target gear stage without suppression of upshifting.

This vehicle control device 10 is provided with: a current gear stage selection unit 13 which selects a current gear stage, which is the gear stage of the vehicle in the present travel state; a travel segment determination unit 15 which determines the next travel segment forwards in the direction of travel of the vehicle V; and a shift control unit 17 which, in the case that the current gear stage selection unit 13 has newly selected a target gear stage lower than the current gear stage during travel of the vehicle V in the current gear stage in the current travel segment, if the next travel segment can be traveled in the current gear stage and the amount the vehicle V will lose speed after traveling the current travel segment is less than or equal to a prescribed threshold value, controls shifting of the gear stage such that downshifting from the current gear stage to the target gear stage is suppressed and the current gear stage is maintained. Even in a state in which downshifting is suppressed, if the state of the vehicle the satisfies a prescribed condition, then the shift control unit 17 controls shifting of the gear stage so as to downshift to the target gear stage without suppression of downshifting.