A transmission speed change control system using effective torque force as a master control parameter instead of throttle percentage signal and engine speed signal. Response time of this system is extremely shorter than existing system, therefore, when this transmission speed change control system is used in cooperation with a continuously variable transmission, the real-time speed ratio matching, can be realized, and the transmission system is maintained in an optimal working condition at any time, so as to improve the transmission efficiency of the transmission system. Meanwhile, the load of the power source can be adjusted without abrupt change. Hence, the work efficiency of the power source is improved, and the service life thereof is prolonged. At the same time, compared with the existing transmission system, the composition and control logic of this control system are simpler and more efficient, and easier to calibrate and adjust.

A method for operating a power shiftable transmission of a motor vehicle, the transmission including a control unit, an input shaft, an output shaft, a gear set, and multiple shift elements, the method including transmitting, with the control unit, a request for a reduction of a drive torque acting on the input shaft for carrying out an upshift, and determining, with the control unit, whether the reduction is completely possible, partially possible, or impossible based on a signal. When the reduction is completely possible, the method includes controlling, with the control unit, a torque transmission rate of a shift element of the multiple shift elements to be engaged during the upshift according to a first way. When the reduction is partially possible or impossible, the method includes controlling, with the control unit, the torque transmission rate according to a second way, the second way differing from the first way.

A control device of a gear transmission-equipped vehicle includes a power controller that starts power reduction control when it is determined that a start condition is satisfied, the power reduction control being control of reducing power transmitted from a driving source to a gear transmission. The start condition includes: a condition that a detection value of a gear position sensor that detects a current gear position of the gear transmission falls within a transition region between engagement regions corresponding to respective gear positions; and a condition that a speed difference obtained by subtracting a rotational speed of an output shaft of the gear transmission from a rotational speed of an input shaft of the gear transmission is a threshold or more.

A method of controlling a vehicle drivetrain by an electric motor, in order to synchronize the speed of an internal combustion engine and the speed of gears in the drivetrain, wherein if a speed synchronization error e.sub.sync(t) is controlled to remain within a prespecified region for a specific period of time, the synchronization is finished, and a gear may be engaged.

With a torque-controlled internal combustion engine and a variable-speed transmission having fixed shift gear ratios, during a shift, the internal combustion engine is controlled in such manner that the drive output torque of the transmission remains the same before and after the shift.

There are provided a transmission control device and a transmission control method that controls a prime mover in a system including the prime mover and a gear transmission. A processing circuitry of the transmission control device executes a process including: determining whether to fall into a predetermined situation at a time of acquiring a shift command; when it is determined as being the predetermined situation, starting a separation control that adjusts an output of the prime mover such that a dog is separated from an abutment surface against which the dog abuts at the time of acquiring the shift command; and after the separation control is completed and before the dog at the first transmission gear position moves out of an accommodation space at the first transmission gear position, starting a synchronous control relating to the dog and transmission gears.

A method of controlling a drive axle system. The method may include executing a gear upshift or a gear downshift after decreasing the torque that is provided by an electric motor to a transmission of an axle assembly and increasing the torque that is provided by another electric motor to a transmission of another axle assembly.

A control device of a gear transmission-equipped vehicle includes a power controller that starts power reduction control when it is determined that a start condition is satisfied, the power reduction control being control of reducing power transmitted from a driving source to a gear transmission. The start condition includes: a condition that a detection value of a gear position sensor that detects a current gear position of the gear transmission falls within a transition region between engagement regions corresponding to respective gear positions; and a condition that a speed difference obtained by subtracting a rotational speed of an output shaft of the gear transmission from a rotational speed of an input shaft of the gear transmission is a threshold or more.

There is provided a transmission control device that controls a first prime mover and a second prime mover of which output responsiveness is different from each other. A processing circuitry of the transmission control device executes a process including: in response to a shift command, calculating each target rotational speed of the first prime mover and the second prime mover for a synchronous control that brings one of rotational speeds of a dog and a transmission gear at the second transmission gear position close to the other; and determining a first timing or a second timing such that the second timing is later than the first timing, the first timing being a time at which the synchronous control of the first prime mover is started, and the second timing being a time at which the synchronous control of the second prime mover is started.

Systems and methods for operating a driveline system are disclosed and include a step-variable transmission. A continuously variable transmission (CVT) is coupled between an input source and the step-variable transmission. The CVT receives a first torque from the input source and outputs a second torque. The CVT has a plurality of planetary members in rolling contact with an inner race and an outer race. A radial distance between the planetary members and a drive-transmitting member corresponds to a transmission ratio of the CVT.