A power transmission system of a vehicle and a gear-shift control method are provided. The power transmission system includes a first drive assembly (101) and a second drive assembly (102). The first drive assembly includes a first automatic transmission (2) and a first motor (1) connected with the first automatic transmission (2) for outputting power to two wheels of the vehicle. The second drive assembly (102) includes a second automatic transmission (2000) and a second motor (1000) connected with the second automatic transmission (2000) for outputting power to the other two wheels of the vehicle. The first and second automatic transmission are configured to be shifted to a preset gear or a gear adjacent to the preset gear, such that when one of the first and second automatic transmission is shifted to the preset gear, the other one of the first and second automatic transmission is shifted to the preset gear or the gear adjacent to the preset gear.

An automatic transmission control device implements a downshift by disengagement of a clutch that is engaged in a gear position before the downshift. It is determined whether an engine state is in a predetermined region in which a change of an engine torque per a change of an accelerator pedal opening is smaller than that in another region, and the engine torque is within a predetermined range, and an engine rotational speed is within a predetermined range. It is determined whether an operating state is in a predetermined state of accelerator operation in which the accelerator pedal opening is larger than a predetermined value, and an accelerator pedal opening change rate has an absolute value smaller than a predetermined value. The downshift is inhibited in response to determination that the engine state is in the predetermined region and the operating state is in the predetermined state of accelerator operation.

An automatic transmission control apparatus includes an engine generating power by a combustion of fuel; an automatic transmission provided with a friction element including a clutch and a brake and changing the power generated in the engine into a torque required depending on a speed by an engagement and release of the friction element to be output; an accelerator pedal position sensor detecting a position signal of the accelerator pedal; and a controller determining whether a vehicle is in a rapid acceleration state from the position signal of the accelerator pedal detected from the accelerator pedal position sensor and correcting a control hydraulic pressure of the friction element if the vehicle is the rapid acceleration state. Since the friction element control hydraulic pressure is controlled depending on the operation speed of the accelerator pedal, the shift responsiveness may be improved.

A shift control apparatus of an automatic transmission may include a data detector configured to detect driving data to perform a shift control, and a vehicle controller configured to determine a shift gear stage based on the driving data and control a transmission based on the shift gear stage, in which the vehicle controller sets driver's demand acceleration based on the driving data, sets a gear stage range which arrives at the driver's demand acceleration, and sets a target gear stage, at which fuel consumption is minimized, in the gear stage range to instruct a shift.

A control apparatus for a vehicle with a continuously variable transmission, having an acceleration requirement determining portion determining operator required acceleration, a first restricted accelerator operation amount setting portion setting an accelerating member restricted operation amount that increases with a running speed increase, when the determining portion has determined required vehicle acceleration, and a shift control portion controlling the transmission speed ratio on the restricted amount basis, the control apparatus having: a second restricted accelerator operation amount setting portion decreasing the restricted amount from a value immediately prior to an accelerating member rapid releasing action determination moment, at a rate lower than an accelerating member operation actual amount decrease rate after the rapid releasing action determination moment, and an upper limit stop processing portion to limit the restricted amount after a determination moment that the operator requires vehicle acceleration, the restricted amount is not larger than the actual operation amount.

An automatic transmission control apparatus includes an engine generating power by a combustion of fuel; an automatic transmission provided with a friction element including a clutch and a brake and changing the power generated in the engine into a torque required depending on a speed by an engagement and release of the friction element to be output; an accelerator pedal position sensor detecting a position signal of the accelerator pedal; and a controller determining whether a vehicle is in a rapid acceleration state from the position signal of the accelerator pedal detected from the accelerator pedal position sensor and correcting a control hydraulic pressure of the friction element if the vehicle is the rapid acceleration state. Since the friction element control hydraulic pressure is controlled depending on the operation speed of the accelerator pedal, the shift responsiveness may be improved.