Abstract: In a constitution where a hydraulic pressure is delivered periodically to friction engagement elements in released states to discharge air mixed into a hydraulic circuit a duty ratio in the hydraulic pressure delivery is switched to a plurality of different values according to operating conditions, a ratio of an actual total time to a target total time is switched per each of duty ratios; and the air discharge control is terminated when a sum of the ratios becomes a predetermined value or above.

Abstract: Grade resistance Ri is calculated based on a driving force, an acceleration degree and rolling/air resistance. When a brake switch is OFF, a down-slope is judged using the grade resistance Ri directly as a value Rif for down-slope judgment. On the contrary, when braking is performed where the brake switch is ON, a minimum value of the grade resistance Ri is peak held, to set the peak held value as the value Rif for down-slope judgment.

Abstract: When a different speed change request occurs during pre-charging, an indicated pressure is stepwise changed up to a standby pressure for after pre-charge, and a processing in accordance with the different speed change request is commenced with the indicated pressure after the stepwise change, as an initial pressure.

Abstract: Grade resistance Ri is calculated based on a driving force, an acceleration degree and rolling/air resistance. When a brake switch is OFF, a down-slope is judged using the grade resistance Ri directly as a value Rif for down-slope judgment. On the contrary, when braking is performed where the brake switch is ON, a minimum value of the grade resistance Ri is peak held, to set the peak held value as the value Rif for down-slope judgment.

Abstract: A hydraulic pressure is supplied to friction engagement elements in the release state to discharge air in the hydraulic circuit when a delivery amount of a hydraulic pump exceeds a predetermined value and when an oil amount required to be supplied to friction engagement elements in the engagement state is less than a predetermined value. The supply of the hydraulic pressure for discharging the air is suspended when the delivery amount is equal to or less than the predetermined value and when the oil amount required to be supplied is equal to or greater than the predetermined value.

Abstract: In a constitution where a hydraulic pressure is delivered periodically to friction engagement elements in released states to discharge air mixed into a hydraulic circuit a duty ratio in the hydraulic pressure delivery is switched to a plurality of different values according to operating conditions, a ratio of an actual total time to a target total time is switched per each of duty ratios; and the air discharge control is terminated when a sum of the ratios becomes a predetermined value or above.

Abstract: A hydraulic pressure is supplied to friction engagement elements in the release state to discharge air in the hydraulic circuit when a delivery amount of a hydraulic pump exceeds a predetermined value and when an oil amount required to be supplied to friction engagement elements in the engagement state is less than a predetermined value. The supply of the hydraulic pressure for discharging the air is suspended when the delivery amount is equal to or less than the predetermined value and when the oil amount required to be supplied is equal to or greater than the predetermined value.

Abstract: When a different speed change request occurs during pre-charging, an indicated pressure is stepwise changed up to a standby pressure for after pre-charge, and a processing in accordance with the different speed change request is commenced with the indicated pressure after the stepwise change, as an initial pressure.

Abstract: A down-shift is carried out when a) the sum of a dry force of a vehicle and a predetermined value, is smaller than a running resistance, and b) when an accelerator opening is larger than a threshold value which is based on vehicle speed, road inclination, and speed change step (gear position).

Abstract: With a speed change control wherein a speed change step is determined corresponding to the gradient of a road surface on which a vehicle is travelling, an upshift requirement is output at the time of a downslope, based on the gradient being gentle, and a reference acceleration and a reference engine load are set corresponding to vehicle speed, speed change step, and gradient. Then, only when an actual acceleration is greater than or equal to the reference acceleration, and an actual engine load is greater than or equal to the reference engine load, is upshift executed based on the upshift requirement, and for other than the above conditions, the upshift requirement is cancelled.

Abstract: A change amount .DELTA.TVO is computed as a deviation of a new value for the throttle opening representing engine load from a previous value. When the change amount .DELTA.TVO is greater than or equal to a positive judgment level TH and engine load is changing rapidly in an increasing direction, computation of running resistance using a detected value for the throttle opening is stopped. However, since when the throttle opening is stable or the throttle opening is changing reducingly, a necessary and sufficient computational accuracy can be maintained, computation of the running resistance is not stopped, and control is carried out based on the computational results.

Abstract: A gearshift controller for an automatic transmission comprises an input shaft torque estimating portion for estimating the input shaft torque, a torque dividing ratio setting portion for setting the torque dividing ratio for each friction member of each gear range, and a desired torque calculating portion for calculating the desired torque of each friction member on the basis of the input shaft torque and the torque dividing ratio, and a desired hydraulic fluid calculating portion for calculating the desired hydraulic fluid pressure for each friction member on the basis of the desired torque of the each friction member, and a hydraulic fluid controlling portion for providing the desired hydraulic fluid pressure to each friction member.

Abstract: Methods and apparatus for controlling the downhill running of a vehicle judge, based on a running resistance of the vehicle, whether a shift-down operation should be carried out or whether a clutch for transmitting power from drive wheels to an engine should be connected. It is judged whether a driver is requesting deceleration by comparing possible acceleration .alpha.s with actual acceleration .alpha.R. A shift-down operation is executed or a clutch connection is carried out only when it is judged that the shift-down operation should be executed or the clutch connection should be carried out and it is judged that the driver is requesting deceleration. Thus, the shift-down operation control is only carried out when the driver intends to decelerate.

Abstract: A shift position is controlled so that a vehicle driving force becomes larger than a corrected vehicle running resistance obtained by adding a correction value corresponding to a surplus driving force to an original running resistance. When the automatic speed control device is operative to drive the vehicle at a constant speed, the correction value is switched to a smaller value compared with when the same is inoperative so that the upshift easily occurs during the constant speed drive.

Abstract: A down-shift acceleration resistance and a down-shift target acceleration are compared, and only when a deceleration intent by the driver is detected, is a down-shift to a gear ratio which is one step higher than a gear ratio which will produce deceleration in excess of that indicated necessary by the comparison, permitted. In the absence of any detected deceleration intent by the driver, a forcible downshifting is inhibited. The shifting is controlled through computation which does not rely on large amounts of prestored table data.

Abstract: The present invention provides for a rapid down-shift to meet an insufficient drive force due to an increase in running resistance such as when ascending a slope. Speed change control is carried out by selecting a speed change step based on the vehicle speed and throttle opening. When there is no speed change requirement, the current running resistance is computed, and the maximum drive force for the current speed change step computed. The maximum drive force is computed based on the down-shift throttle opening corresponding to the current vehicle speed on a down-shift line from the current speed change step to a speed change step on a lower speed side. The running resistance and maximum drive force are compared, and when the maximum drive force is less than the running resistance a forceful down-shift is made.