Abstract: In a system for controlling an automatic transmission, an ECU is constructed to carry out changeover control in accordance with shift determination from second speed to first speed to achieve release of a second engaging element and engagement of a first engaging element, detect a magnitude of a torque signal before a predetermined time of shift determination when the changeover control is carried out, and control release of the second engaging element in accordance with the magnitude of the torque signal.

Abstract: In a shift control system for an automatic transmission, shelf-pressure control means include means for increasing the engagement pressure of the friction elements at a first gradient as previously set after output of the shift command, wherein after output of the shift command and when start of the inertia phase is detected, a torque-reduction command is output to the torque-reduction control means, the engagement pressure at detection of the inertia phase is set as an initial shelf pressure to increase the shelf pressure at a second gradient set for each speed, and a torque variation part oil pressure is added only when detecting a variation in throttle opening, and wherein after start of the inertia phase and when completion of the inertia phase is detected, a torque-reduction completion command is output to the torque-reduction control means.

Abstract: There is provided a hydraulic control device for an automatic transmission, which is comprised of an engagement state determining section and a protection control section. If the engagement state determining section determines that each clutch, which is supplied with a line pressure via a regulating valve having a spool and has an oil pressure switch disposed in an oil channel, is held in an engaged state when gears are not changed, the protection control section sets a command pressure for the regulating valve to a protective oil pressure lower than the line pressure. This brings the regulating valve into a pressure-regulating state to cause lands of the spool to form apertures that reduce hydraulic vibration applied to the line pressure. This inhibits an oil pressure beyond an acceptable value from being applied to the oil pressure switch, and therefore improves the durability of the oil pressure switch.

Abstract: In a shift control system for an automatic transmission, shelf-pressure control means include means for increasing the engagement pressure of the friction elements at a first gradient as previously set after output of the shift command, wherein after output of the shift command and when start of the inertia phase is detected, a torque-reduction command is output to the torque-reduction control means, the engagement pressure at detection of the inertia phase is set as an initial shelf pressure to increase the shelf pressure at a second gradient set for each speed, and a torque variation part oil pressure is added only when detecting a variation in throttle opening, and wherein after start of the inertia phase and when completion of the inertia phase is detected, a torque-reduction completion command is output to the torque-reduction control means.

Abstract: A shift control apparatus is arranged to effect a shift in an automatic transmission by changeover of friction elements to be engaged with disengagement of a disengagement-side friction element and engagement of an engagement-side friction element. A shift controller is configured to detect an end of a loss stroke in the engagement-side friction element, and performs an operation to decrease the disengagement-side working oil pressure at a set gradient and to increase the engagement-side working oil pressure at a predetermined gradient upon detection of the end of the loss stroke in the engagement-side friction element. The predetermined gradient of the engagement-side working oil pressure for the engagement-side friction element is made lower for a low engine load than for a high engine load.

Abstract: In a system for controlling an automatic transmission, an ECU is constructed to carry out changeover control in accordance with shift determination from second speed to first speed to achieve release of a second engaging element and engagement of a first engaging element, detect a magnitude of a torque signal before a predetermined time of shift determination when the changeover control is carried out, and control release of the second engaging element in accordance with the magnitude of the torque signal.

Abstract: There is provided a hydraulic control device for an automatic transmission, which is comprised of an engagement state determining section and a protection control section. If the engagement state determining section determines that each clutch, which is supplied with a line pressure via a regulating valve having a spool and has an oil pressure switch disposed in an oil channel, is held in an engaged state when gears are not changed, the protection control section sets a command pressure for the regulating valve to a protective oil pressure lower than the line pressure. This brings the regulating valve into a pressure-regulating state to cause lands of the spool to form apertures that reduce hydraulic vibration applied to the line pressure. This inhibits an oil pressure beyond an acceptable value from being applied to the oil pressure switch, and therefore improves the durability of the oil pressure switch.

Abstract: A shift control system of an automatic transmission executes an interchange shift by interchanging engagement conditions of first and second friction elements of the automatic transmission. The first and second friction elements are engaged and disengaged according to oil pressures supplied thereto. A controller of the shift control system is arranged to decrease the second oil pressure of the second friction element by a second predetermined gradient and to increase the first oil pressure of the first friction element by a first predetermined gradient after the loss stroke of the first friction element is terminated, and to determine the first gradient such that a difference between a command pressure and an actual pressure of the first friction element is kept substantially constant.

Abstract: As the disengage pressure command value PO lowers and as the engagement pressure command value PC rises, a changeover shift is effected by bringing a disengagement side friction element into disengagement and a disengagement side friction element into engagement. The rising gradient of the engagement pressure command value PC at and after the ON instant t2 of the oil pressure switch, when the engagement side friction element takes the engaging capacity, is made as low as &ggr;1 for a low throttle opening degree but as high as &ggr;2 for a high throttle opening degree, and the lowering gradient of the disengagement side pressure command value PO is also made as small as &bgr;1 at the low throttle opening degree and as large as &bgr;2 at the high throttle opening degree.

Abstract: In gear-shift control performed during normal travelling, a drive frequency of each solenoid valve is set to a higher one to suppress fluctuations or changes of a quantity or speed of a flow of a hydraulic oil concerned when the solenoid current is turned on/off to suppress fluctuations of the output hydraulic pressure. In start selection, the drive frequency of the solenoid valve is set to a lower one to reduce the number of times a plunger and a ball hit each other within the solenoid valve to reduce a sound produced by the operation of the solenoid.

Abstract: A shift control system of an automatic transmission executes an interchange shift by interchanging engagement conditions of first and second friction elements of the automatic transmission. The first and second friction elements are engaged and disengaged according to oil pressures supplied thereto. A controller of the shift control system is arranged to decrease the second oil pressure of the second friction element by a second predetermined gradient and to increase the first oil pressure of the first friction element by a first predetermined gradient after the loss stroke of the first friction element is terminated, and to determine the first gradient such that a difference between a command pressure and an actual pressure of the first friction element is kept substantially constant.

Abstract: During a shifting operation that a first engaging element is changed from an engaged state to a disengaged state, a fail-safe valve is used to forcibly drain a first engaging-element pressure from the first engaging element by using a second engaging-element pressure applied to a second engaging element brought into an engaging state from a releasing state. The fail-safe valve includes a spool and uses the second engaging-element pressure acting on the spool in one axial direction and an opposing pressure acting on the spool in the opposing direction as operating signal pressures. The fail-safe valve is switchable to a drain position, when the second engaging-element pressure is regulated toward a specified fail-safe valve operating point pressure higher than a maximum pressure value of the second engaging-element pressure regulated during the shifting operation and lower than a maximum possible engaging-element pressure.

Abstract: A sealless accumulator 14, which intervenes between a solenoid valve 4 and a spool valve 5 for absorbing vibrations of a hydraulic oil concerned, is disposed in an upper half of a valve body above an oil path 18 formed in the upper half of the valve body 16. Air discharge path 24 is provided on an opposite side of an accumulator 14 from its oil chamber in which the oil pressure is applied to the piston 22 such that when the oil pressure is applied to the oil path 18, the piston 22 is moved, the hydraulic oil is discharged through the air discharge path 24 to the outside, possible air present up within the oil path 18 flows into the accumulator 14, and then is discharged through the air discharge path 24 to the outside.

Abstract: An anti-creep control apparatus has a forward clutch control section that controls the hydraulic pressure of a forward clutch so as to slip the forward clutch when an automatic transmission is set in a drive range and the vehicle is stopped. The anti-creep control apparatus sets a target engagement time that is inversely proportional to the engine rotation speed at the time just before starting anti-creep control. The anti-creep control apparatus controls an oil pressure modulator so that one of a slip amount of the forward clutch and the output shaft rotation speed of the torque converter becomes nearly zero when the target engagement time elapses.

Abstract: A rotation clutch device rotates on an axis of an automatic transmission. The rotation clutch device comprises a clutch piston which slides around the axis of the automatic transmission for the engagement of the clutch device. First and second chamber are formed to slide the clutch piston in the direction of the engagement by receiving hydraulic pressure respectively. A cancel chamber is formed opposite to the first and second chambers through the clutch piston to cancel the centrifugal pressure generated in the first and second chambers. A selector valve selectively supplies hydraulic pressure to the first and second chambers according to a selected shift position of the automatic transmission to adapt to a different required engagement capacity in each shift position.

Abstract: A shift control apparatus of an automatic transmission executes a transient control of an engagement pressure of a first speed selecting friction element when a first speed is selected after a higher speed is once selected during a change from a neutral range to a forward drive range. A band brake pressure for selecting the second speed is rapidly increased at a first moment. A forward clutch pressure for selecting the first speed is increased at a second moment delaying to the first moment by a predetermined period adjusted to a line pressure lowered period. The forward clutch pressure is pre-charged during a period between the first and second moments, then being hold for a preset time period at a return spring corresponding pressure adjusted by a leaning control, and being increased by a slope adjusted by the leaning control for a predetermined period to establish the second speed by the engagement of the forward clutch.

Abstract: In apparatus and method for controlling a gear shift of a vehicular automatic transmission, the automatic transmission the automatic transmission having a releasing frictional element, a clutching frictional element, and a source of a releasing working liquid pressure to be applied to the releasing frictional element and a clutching working liquid pressure to be applied to the clutching frictional element, a gear shift in the automatic transmission being carried out by a shift from the releasing frictional element to the clutching frictional element, during a time duration from a time at which a gear shift instruction is outputted to a time at which a torque phase is started, the releasing working liquid pressure is reduced and reached without undershooting to a first predetermined working liquid pressure value under which the releasing frictional element is in a state immediately before an occurrence of a slip and the clutching working liquid pressure is set at least a second predetermined working liquid pre

Abstract: An anti-creep control apparatus of an automatic transmission has a forward clutch control section which controls the hydraulic pressure of a forward clutch by slipping the forward clutch when the automatic transmission is set in a drive range and the vehicle is stopped while an engine is operating. The anti-creep control apparatus controls an hydraulic pressure of the forward clutch to be held or increased by a predetermined value when a relative rotation of the forward clutch is detected during the anti-creep control. The controlled hydraulic pressure is set as a lower limit value of the forward clutch hydraulic pressure in a present anti-creep control.

Abstract: An automatic transmission with an anti-creep control apparatus includes a torque converter connected to the engine, first and second friction elements, and a control unit. The first friction element is operated when the automatic transmission is put in a drive range. The second friction element performs to prevent a reverse rotation of an output shaft of the automatic transmission. The control unit executes an anti-creep control controls, controlling the second friction element to prevent a reverse rotation of an output shaft of the automatic transmission when the anti-creep control is executed, holds the engagement of the second friction element during a time period from the time when the anti-creep control is cancelled to the time when the first friction element is fully engaged, and disengages the second friction element thereafter.

Abstract: A vibration damping equipment for a torsional damper comprises a hub plate, side plates, a torsion spring, a friction block, and low rigidity members. Each low rigidity member is interposed between the hub plate and each friction block to be adjacent to each other through a partition of the hub plate. The low rigidity members are connected to each other on at least one axial side of the partition.