A method of operating a vehicle having an engine, a throttle valve and a throttle operator. A continuously variable transmission is operatively connected to the engine and has a driving pulley, a driven pulley, and a belt operatively connecting therebetween. At least one ground engaging member is operatively connected to the driven pulley and includes at least one of a wheel and a track. A piston is operatively connected to the driving pulley for applying a piston force to the driving pulley when actuated and thereby changing an effective diameter of the driving pulley. A control unit controls actuation of the piston and the piston force. The method includes determining an engine speed, and controlling the piston force based on the engine speed.

A method of operating a vehicle having an engine, a throttle valve and a throttle operator. A continuously variable transmission is operatively connected to the engine and has a driving pulley, a driven pulley, and a belt operatively connecting therebetween. At least one ground engaging member is operatively connected to the driven pulley and includes at least one of a wheel and a track. A piston is operatively connected to the driving pulley for applying a piston force to the driving pulley when actuated and thereby changing an effective diameter of the driving pulley. A control unit controls actuation of the piston and the piston force. The method includes determining an engine speed, and controlling the piston force based on the engine speed.

When the vehicle speed increases and reaches a predetermined switching threshold, the controller reduces the displacement of the first travel motor and controls the flow rate control device to offset a flow rate excess in the hydraulic circuit in accordance with the reduction in the displacement of the first travel motor. After the vehicle speed has reached the switching threshold, the controller executes switching control to switch the clutch from an engaged state to a disengaged state.

When the vehicle speed increases and reaches a predetermined switching threshold, the controller reduces the displacement of the first travel motor and controls the flow rate control device to offset a flow rate excess in the hydraulic circuit in accordance with the reduction in the displacement of the first travel motor. After the vehicle speed has reached the switching threshold, the controller executes switching control to switch the clutch from an engaged state to a disengaged state.

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 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 the gear shifting of an automatic range-change transmission, which is arranged between a drive engine and a final drive in a drive train of a motor vehicle and includes at least one multi-stage main transmission, a two-stage front-mounted group upstream of the main transmission, and a transmission brake. The main transmission can be shifted, via unsynchronized clutches, and the front-mounted group can be shifted, via synchronized clutches. Upon upshifting in the range-change transmission including at least one change of a transmission ratio stage of the front-mounted group, synchronization of the front-mounted group is effected via actuation of the synchronized clutch of the front-mounted group and supportingly via at least intermittently parallel actuation of the transmission brake. Actuation of the transmission brake, for supporting the synchronization of the front-mounted group, is effected on the basis of a prevailing driving or operating situation.

An automatic transmission control device includes diagnosis means configured to perform an abnormality diagnosis of a rotation sensor on the basis of a maximum cycle and a minimum cycle of a plurality of the pulse signals in a predetermined period.

Disclosed is a method of controlling a shifting time and a transmission controlled by the method. A method of controlling a shifting time of an automatic transmission mounted on a vehicle to control the driving of the transmission by incorporating the state of an engine includes an entry condition determination step of determining whether the engine of the vehicle being driven is a full throttle driving state and a shifting point correction logic entry condition is satisfied, an engine speed calculation step of calculating an expected maximum engine speed during gear shifting, and a shifting time delay step of delaying a shifting time during a specific time if an expected maximum engine speed value calculated in the engine speed calculation step is less than a preset value. Accordingly, a shifting pattern into which maximum acceleration performance set through maximum performance of an engine has been incorporated can be implemented.

An alternator driving apparatus for driving an alternator may include a crank pulley mounted on a crank shaft of an engine, an alternator pulley connected to the crank pulley through a driving belt, an alternator shaft connected between the alternator and the alternator pulley, and a rotation speed varying mechanism configured to vary a rotation speed of the alternator shaft.