Abstract: A transmission system includes a first clutch, a second clutch, and a controller. The controller communicates with the first and second clutches and commands a gear shift. The controller calculates a torque phase time for the gear shift and determines a desired torque trajectory within said torque phase time. The controller determines on-coming torque values for the second clutch and off-going torque values for the first clutch to achieve the desired torque trajectory within the torque phase time. The controller calculates an on-coming clutch pressure based on the on-coming torque value, and an off-going clutch pressure based on the off-going torque value. The controller delays actuation of the first and second clutches to compensate for hydraulic delays.

Abstract: A control apparatus for controlling a shift operation in an automatic transmission includes a disengaging side controlling device for performing a feedback control so as to substantially match a slip amount calculated by a slip amount calculating device with a target slip amount calculated by a target slip amount calculating device when the calculated slip amount is judged to be in excess of the predetermined threshold value by a judging device. The target slip amount varies from a predetermined threshold value to a predetermined target value drawing an ideal trace for restraining a shift shock and is maintained at the predetermined target value. The control apparatus further includes an engaging side controlling device for increasing a torque to be transmitted to an on-coming friction engagement element in association with commencement of the feedback control.

Abstract: According to an aspect of the present invention, an automatic transmission includes plural friction engaging elements configures plural shift ranges based on combinations of each friction engaging element being in engaging or disengaging condition, a controlling unit for controlling the friction engaging elements to be in engaging or disengaging condition by controlling a hydraulic pressure applied.

Abstract: When it has been determined that control for a predetermined upshift has been started while an accelerator pedal was not being depressed, and that a factor that changes an input torque of an automatic transmission has been generated, an engaging pressure of a predetermined hydraulic frictional engagement device is corrected by a correction amount in accordance with the factor that changes the input torque. As a result, undershooting of an engine speed, as well as shift shock which results from that undershooting, is able to be preferably suppressed.

Abstract: When a clutch is disengaged in a D-N shift, a duty ratio of a linear solenoid in a stand-by state at a constant pressure is calculated according to the following equation by using the following values: a reference duty ratio in a stand-by state at a constant pressure; a correction value for an AT oil temperature; a correction value for an engine speed; and respective learning correction values in a N-D shift and a 4-3 coast down shift in which the clutch is engaged. In the equation, K is a coefficient and has a constant value predetermined in the range of 0≦K≦1.

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: Described is a method for the control of a transmission of a motor vehicle, especially an automatic transmission, with hydraulically activated shifting elements. The shifting elements are shifted to engage or disengage by means of specified pressure pattern (pkab, pkzu) which have been input into an electronic control unit. In the said method, an applied pressure (pkab) on a disengaged shifting element, by the release of a force flow generated by a holding pressure (pkab-h) is reduced to a shift pressure (pkab-sd) and a transmission input speed of rotation (nt) experiences a change dependent upon the applied pressure (pkab) on a disengaged shifting element.

Abstract: A hydraulic change speed system for a working vehicle includes a gear type change speed device shiftable by an actuator, a hydraulic clutch connected to a power transmission line including the gear type change speed device, a valve unit for switching operative states of the hydraulic clutch, a controller for controlling the valve unit, and a timer for measuring a shifting time of the gear type change speed device. The valve unit is interlocked to the actuator to be controllable to pressurize the hydraulic clutch rapidly for a predetermined time from a start of engagement of the hydraulic clutch and to pressurize the hydraulic clutch gradually the predetermined time. The controller sets the predetermined time based on the shifting time measured.

Abstract: In gear shift controlling method and apparatus for an automatic transmission, the automatic transmission comprising a plurality of frictional elements, a working liquid pressure for each of first and second frictional elements is controlled to make a gear shift in the automatic transmission in such a manner that while the first frictional element is released by a decrease pressure control for the working liquid pressure, the second frictional element is clutched by an increase pressure control for the working liquid pressure and a release capacity during an inertia phase during which the gear shift from a first gear range to a second gear range occurs is set in accordance with an instantaneous gear ratio during the inertia phase so as to output the release capacity set according to the instantaneous gear ratio.

Abstract: An automatic shift-down apparatus for an automatic transmission which comprises vehicle speed detection device for detecting the speed of a vehicle; vehicle-speed variation rate calculation device for calculating the variation rate of the detected vehicle speed; shift-start vehicle speed calculation device for calculating, on the basis of the calculated vehicle-speed variation rate and a time required to complete a shift operation, a shift-start vehicle speed which enables the shift operation to finish before the vehicle speed attains a shift-completion speed; and a shift device which starts a shift operation when the detected vehicle speed attains the calculated shift-start vehicle speed.

Abstract: In an automatic transmission, transient control of the working oil pressures for friction elements whose state is to be switched is normally carried out in accordance with a degree of shift development determined based on at least a vehicle speed. When the vehicle speed is too low to provide determination of the degree of shift development, transient control of the working oil pressures for the friction elements is carried out in accordance with elapsed time from shift instead of normal transient control.

Abstract: In an automatic transmission having a torque converter interposed between an engine and a transmission mechanism, the torque converter includes a lock-up clutch capable of directly coupling an output shaft of the engine and an input shaft of the transmission mechanism. A speed difference detector is provided for detecting a difference between engine rotational speed and input shaft rotational speed. An engine speed controller means is also provided for controlling the engine speed to cause the speed difference to converge within a predetermined range. By detecting the speed difference, it is possible to precisely detect the actual vehicle state, and to reliably and smoothly engage the lock-up clutch without generating shift shock in any vehicle state. With this structure, the lock-up clutch can be reliably engaged and the engine brake can be secured.

Abstract: When a contradictory event in which raising of the engine rotation speed is detected and the inertia phase start time is early occurs (8), a learn correction is made to engagement hydraulic pressure (ON side). If the raising of the engine rotation speed cannot be canceled still after the learn correction is made, release hydraulic pressure (OFF side) is increased for correction.

Abstract: A speed change mechanism (1) constructed by connecting in tandem a hydraulic type speed change unit (17) having a plurality of hydraulic clutches (57, 58, 59) to be alternatively engaged and a hydraulic type speed change unit (20) having a plurality of hydraulic clutches (66, 67, 68) to be alternatively engaged, wherein a time-varying region (common slip region) is secured in which the two clutches slip in common such that during speed change, when the working hydraulic pressure in a clutch to be engaged is on its way to gradual increase, the working hydraulic pressure in a clutch to be disengaged lowers.

Abstract: In a shift control method for an automatic transmission, it is first determined a signal for shifting from a reverse range to a drive range is input, then further determined if an engine is in an idle state. An initial shifting signal of a first duty ratio is output to a drive unit and maintained the first duty ratio for a first predetermined fill time. Next, the first duty ratio is reduced to a second duty ratio and outputting a signal of the second duty ratio for a soft engagement control to the drive unit, and it is determined if a current turbine rpm is less than a first predetermined value which is obtained by extracting a second predetermined value from a target turbine rpm. Next, a feedback duty control signal is output to the drive unit, and it is determined if a turbine rpm variation is higher than a third predetermined value or if the turbine rpm is less than a fourth predetermined value.

Abstract: Disclosed is a method for controlling runup comprising the steps performing upshifting from a second speed to a third speed if throttle opening and vehicle speed are at predetermined levels; determining if runup occurring at the point where upshifting from the second speed to the third speed is performed, the determination of the occurrence of runup being performed based on turbine rpm, transmission output rpm and a second speed gear ratio; determining if a time rate of change in turbine rpm is less than 0 if runup is occurring; reducing a duty for a predetermined time period if the time rate of change in turbine rpm is greater than 0; and performing feedback control if the time rate of change in turbine rpm is less than 0.

Abstract: A travel speed controller for use in an electrically powered light weight vehicle with a battery-powered motor and a control circuit. If an operator applies some accelerating force or a physical force, to the vehicle body, the control circuit receives a plus signal from a rotation transmission means attached to its wheel, corresponding to the accelerating force, and calculates an acceleration based on operation treatment of variation of time intervals of the pulse signal, memorizes the acceleration, and supplies to the motor a driving electric current corresponding to the memorized acceleration. If a higher acceleration is calculated, the memorized acceleration is renewed and a driving electric current is supplied to the motor, corresponding to the renewed acceleration.

Abstract: An output bearing assembly of a transmission includes a housing, and a pair of bearings. At least one speedometer sensor is mounted between the bearings. The arrangement allows the output bearings to be spaced axially by a relatively great distance.

Abstract: A power Off upshift control method for an automatic transmission includes the steps of determining, during an upshift operation, if power Off upshifting is taking place; determining if power Off upshift conditions are satisfied; measuring a hydraulic pressure response time, establishing a maximum duty value for preventing forced shifting, and calculating the hydraulic pressure response time when the maximum duty value changes to 100% duty, these processes being performed if the power Off upshift conditions are satisfied; calculating a shift finish point after the hydraulic pressure response time is calculated; determining if the shift finish point corresponds to an actual shift finish point; and setting the maximum duty value at 100% duty if the shift finish point corresponds to the actual shift finish point.

Abstract: An apparatus for controlling a vehicle automatic transmission, wherein a moment at which the supply of a pressurized fluid to a hydraulic cylinder for engagement of a frictional coupling device to effect an upshift of the transmission during running of the vehicle in a power-off state is initiated is determined by comparing an estimated synchronizing time required for the transmission input speed to reach a synchronizing speed of a higher-gear position to which the transmission is shifted, with a stored predetermined stroking time required for the piston of the hydraulic cylinder to reach its engaging stroke end.

Abstract: An improved automatic shift transmission control method establishes an initial methodology for sharing adaptive corrections among shift parameters stored for related types of shifts, and subsequently modifies the initial methodology as the adapted parameters converge on respective optimum values. Individual shift types are initially categorized to indicate the degree of cross-adaptive correction, and when shift parameter convergence occurs, the shift types are re-categorized, thereby modifying the initial cross-adaptive methodology to restrict further cross-adaptive correction. A given shift type is automatically reset to an initial or prior categorization to permit less restricted cross-adaptive correction if reset conditions are met. In this way, the methodology for sharing adaptive corrections automatically evolves to suit individual transmission operating characteristics and conditions, and effectively prevents degradation of a shift due to sharing of adaptive corrections developed for a related shift.

Abstract: Torque phase detecting means 110 detects the starting point of a torque phase in an automatic transmission. Racing detecting means 120 detects a racing. Control means 140 shifts disconnecting or connecting hydraulic pressure or timing in the next automatic transmission according to whether the racing means 120 occurred before or after the starting point of a torque phase detected by said torque phase detecting means 110. An automatic transmission control unit which suppresses racing without giving any shock to the driver can be obtained.

Abstract: An improved control for an automatic transmission closed-throttle downshift, wherein closed-throttle engine torque is used to raise the transmission input speed to the synchronous speed of the target speed ratio, and wherein the on-coming clutch is controlled in a manner to complete the shift with minimum driveline torque disturbance in spite of clutch control variability. The invention includes a primary on-coming clutch control for completing the downshift when the input speed reaches the synchronous speed, and a contingent on-coming clutch control that is initiated if shift completion is not achieved by the primary control, the contingent control being effective to re-establish input speed synchronization and thereupon engage the on-coming clutch to complete the shift.

Abstract: An improved control for an automatic transmission garage shift, wherein a dynamic model of the transmission is used to estimate the transmission input torque during the shift and to schedule the on-coming clutch pressure in accordance with the estimated input torque to achieve a desired input shaft trajectory. The transmission input torque is estimated based on two different methodologies —one suited to steady-state engine idle conditions, and the other suited to engine output torque transient conditions. A fuzzy summation of the input torques provided by the two methodologies is utilized in transitions between the two conditions. Shift quality variations due to variations in mechanical and/or hydraulic stiffness are minimized by a pause or hold interval inserted between the end of the fill period and the initiation of on-coming clutch pressure control, which results in a reasonably consistent degree of perceived transmission-to-transmission hydraulic and mechanical compliance.

Abstract: When a contradictory event in which raising of the engine rotation speed is detected and the inertia phase start time is early occurs (8), a learn correction is made to engagement hydraulic pressure (ON side). If the raising of the engine rotation speed cannot be canceled still after the learn correction is made, release hydraulic pressure (OFF side) is increased for correction.

Abstract: A shift control apparatus comprises clutches driven by shift solenoids and whether or not the raising of the rotation speed occurs in an internal combustion engine is determined. If the raising of the engine rotation speed is detected, a hydraulic pressure learn correction is made to engagement hydraulic pressure and a time learn correction is made to the hydraulic pressure supply preparation time. The correction ratio of the energization-hydraulic pressure characteristic (I-P characteristic) of clutch clearance and the shift solenoid is set so as to become an appropriate distribution ratio and the learning is started based thereon.

Abstract: A vehicle control system comprising a vehicle speed sensor for detecting the speed of a vehicle; a road situation storage device for storing road structures and conditions; a recommended gear stage determining device for determining a recommended gear stage of an automatic transmission on the basis of the vehicle speed and the road structures and conditions; a present position detecting device for detecting the present position of the vehicle; a present position recognizing device for recognizing the present position of the vehicle, as detected by the present position detecting device; a control content selecting device for evaluating at least one of the present position detecting device and the present position recognizing device to select the control content on the basis of the evaluation result; and a speed change processing device for changing the speed in accordance with the control content selected by the control content selecting device.

Abstract: An improved diagnostic control method for a motor vehicle powertrain including an electronically controlled multi-range transmission and a multi-range transfer case, wherein a default determination of transfer case range enables reliable evaluation of transmission ratio, for powertrain configurations with or without a transfer case range indicator switch. An overall speed ratio is computed according to a ratio of the transmission input speed and the transfer case output speed, and the computed ratio is monitored to identify a period of stable operation at the conclusion of transmission shifting and in steady state operation during which the rate of change of the computed ratio is stable over a predefined interval. If the computed ratio is also deemed to be stable, it is compared with an expected overall ratio based on an assumed speed range (low or high) of the transfer case.

Abstract: A controller of an automatic transmission having a lockup clutch and a control method of the automatic transmission, in which engine rotational speed is prevented from changing even though turbine rotational speed changes at gear shift and slip control can be carried out without making a driver feel uncomfortable are provided. When a speed change command is detected and it is determined that an inertia phase has not yet started, target engine rotational speed during a replenish period is calculated and the target engine rotational speed control is carried out to have the target engine rotational speed. When it is determined that the control is in the inertia phase, another target engine rotational speed during the inertia phase is calculated. Then, target engine rotational speed control in which the engine rotational speed at the start of the inertia phase is maintained as the target engine rotational speed is carried out.

Abstract: A method for pressure adaptation is proposed for an automatic transmission. The gear shifts here are carried out as overlapping gear shifts with a first opening (K1) and a second closing (K2) clutch, the overlapping gear shift consisting of a first and a second phase. During the first phase, a banking of the transmission input rotational speed (nT) is adjusted. The invention proposes that upon issuance of the shift command, a time period (t2) is determined until the transmission input rotational speed has reached the banking value (dn). This is compared with a predetermined time (tAD) during which a difference is obtained which provided with a sign is totaled in a summation memory. An adaptation value is stored in a correction value memory when the summation memory exceeds a limit value. As consequence of this, the disconnection pressure level (pAB) of the first clutch (K1) is adapted in subsequent gear shifts.

Abstract: Control apparatus having improved characteristics at an early stage of changing the gear position which make it possible to clearly discriminate the change in the transmission input shaft revolution speed caused by a rise in the engine torque by depressing the accelerator pedal from changes attending on the disengagement of the disengaging side clutch. For the above purpose, the control apparatus adopts a configuration capable of correcting the oil pressure acting on the friction coupling device by an arrangement that the transmission output shaft revolution ratio, obtained from the transmission output shaft revolution speed and the transmission input shaft revolution speed, follows up the target value of the revolution ratio after a speed change signal is issued.

Abstract: The invention relates to a method for increasing the spontaneity of automatic gear boxes with overlapping gear shifts. The overlapping gear shifts consist of three phases. Upshifting from a first gear ratio to a second gear ratio is aborted and downshifting to a first gear ratio occurs if an abort criterion is detected. The abort criterion is validated if a request for downshifting is made by the driver and detected before the third overlapping shift phase begins.

Abstract: Disclosed herein is a speed change transition control apparatus for an automatic transmission. The speed change transition control apparatus comprises rotational speed detection unit for detecting an input shaft rotation speed of the speed change mechanism, and a feedback control unit for controlling engagement pressure through a fluid pressure control element in such a manner that the input shaft rotation speed during a speed change follows a target rotation slope with an actual input shaft rotation speed detected at an actual inertia phase start point by the rotational speed detection unit as its starting point.

Abstract: A method for increasing the spontaneity is proposed for an automatic transmission, the gear shifts of which are carried out as overlapping gear shifts. Here an upshift from a first to a second gear is not completely terminated and a change back from an upshift to the first gear is carried out when an abort criterion is detected.

Abstract: In a gearshift control apparatus for an automatic transmission wherein the torque capacity of a release side clutch is gradually lowered, and the torque capacity of an engagement side clutch is gradually raised, whereby the release side clutch and the engagement side clutch are changed-over to effect a clutch-to-clutch gearshift; control means issues two control commands to the engagement side hydraulic control mechanism in a term which extends until an inertia phase begins since start of the gearshift control. A first hydraulic pressure command (D1) is issued for a predetermined time period. The first hydraulic pressure command (D1) is variable for adjusting the timing of the changeover between the clutches. The second hydraulic pressure command (D2) succeeding the first one is issued until the inertia phase begins. The second hydraulic pressure command is variable for adjusting the torque capacity of the engagement side clutch at the changeover.

Abstract: In executing a clutch-to-clutch gearshift based on the release and engagement of two clutches by the control of the hydraulic pressures of the clutches, the fluctuating magnitude of the output shaft r.p.m. (No in FIG. 2) of the automatic transmission is calculated, and the degree of the drag (tie-up) state of the clutches is detected on the basis of the calculated fluctuating magnitude. As a result, the pressure increasing/decreasing timings of the hydraulic pressures of the clutches can be optimized to realize a feedback control or learning control of higher precision.

Abstract: A process is provided for operating a vehicle transmission with preferably electrohydraulically actuatable friction elements for shifting between different transmission steps, in a vehicle with at least one drive engine in which an actual value of at least one of the quantities characterizing the shift process is determined for each shift process, which actual value is compared with a theoretical value that can be established and stored. When the actual value deviates from the theoretical value, a regulated quantity for at least direct influencing is changed by a correction value that can be established. For each shift process, the time duration for the output of a gear shift signal up to the beginning of the synchronization process and/or the change of the drive rpm during this time period is determined as a first and/or second actual value of the quantity characterizing the process.

Abstract: In an automotive transmission, a method for determining whether an upshift should be enabled or disabled determines the predetermined upshift vehicle speed at which the upshift is scheduled to occur with reference to current throttle position and vehicle speed. The method employs the difference between upshift vehicle speed and current vehicle speed, the current vehicle acceleration, an empirically determined upshift vehicle acceleration referenced to current vehicle speed and the speed difference. If the current vehicle acceleration is equal to or greater than upshift vehicle acceleration, the upshift is enabled; otherwise, the scheduled upshift is disabled.

Abstract: An apparatus for controlling the pressure of a hydraulically operated frictional coupling device which is released or engaged to achieve a shifting action of an automatic transmission, by first rapidly reducing or increasing the pressure to a predetermined level, holding the pressure at this level for a predetermined time and then continuously reducing or increasing the pressure to complete the shifting action, wherein a learning compensation device is provided to update, by learning compensation, a selected control parameter influencing a pattern of change of the pressure of the coupling device during the shifting action such that the shifting action is achieved in a predetermined manner.

Abstract: A shift control unit which improves the shift feeling of an automatic transmission includes an operation control device for placing a frictional engaging element in a slow drain state during a timing time decided by a timing time deciding device and in a quick drain state when the timing time has elapsed.

Abstract: Described are apparatus and method for monitoring revolution speed values detected by corresponding revolution speed sensors too determine whether at least any one of an engine revolution speed sensor, a continuously variable transmission input axle revolution speed sensor, and a continuously variable transmission output axle revolution speed sensor has failed according to detected values of the engine revolution speed sensor, the input axle revolution speed sensor, and the output axle revolution speed sensor and a detected value of an instantaneous gear shift ratio when a lock-up mechanism is in a lock-up state. If all of three formulae on predetermined correlations are established, all of the sensors are determined to be normally operated. If any one or two of the three formulae are not established, the failure one of the three sensors is identified. The three correlation formulae are based as follows: 1) N.sub.E =N.sub.PRI ; 2) N.sub.PRI =N.sub.SEC .times.CN; and 3) N.sub.E =N.sub.PRI .times.C.sub.

Abstract: An apparatus for controlling an automatic transmission of a motor vehicle, wherein a shift-down action of the automatic transmission is achieved with a releasing action of a hydraulically operated frictional coupling device, the apparatus including a rapid pressure reduction device operated upon determination that the shift-down action should be effected, for rapidly reducing a pressure of the frictional coupling device to a predetermined pressure level higher than a critical level at which the frictional coupling device starts slipping, an input torque determining device for determining an input torque of the automatic transmission, or a rate of increase of the input torque, and a rapid pressure reduction amount determining device for determining the predetermined pressure level to which the pressure of the frictional coupling device is reduced, on the basis of the input torque or the rate of increase thereof of the automatic transmission determined by the input torque determining device.

Abstract: A vehicle automatic transmission control controls fluid pressure changes applied to a frictional engagement element which is being changed from an engaged state to a disengaged state at a stage before input shaft rotational speed starts to increase from the beginning of a down-shift control. The control instruction value is set to gradually decrease the applied fluid pressure and to increase the ratio of such decrease with elapsed time. Specifically, a solenoid is used to control the fluid pressure applied to a clutch. The duty-cycle instruction for the solenoid is determined based on a quadratic function expressed as: duty cycle value=initial value-at.sup.2.

Abstract: A controller of an automatic transmission having a lockup clutch and a control method of the automatic transmission, in which engine rotational speed is prevented from changing even though turbine rotational speed changes at gear shift and slip control can be carried out without making a driver feel uncomfortable are provided. When a speed change command is detected and it is determined that an inertia phase has not yet started, target engine rotational speed during a replenish period is calculated and the target engine rotational speed control is carried out to have the target engine rotational speed. When it is determined that the control is in the inertia phase, another target engine rotational speed during the inertia phase is calculated. Then, target engine rotational speed control in which the engine rotational speed at the start of the inertia phase is maintained as the target engine rotational speed is carried out.

Abstract: Upshifting is performed in a short time without giving rise to shocks. For that purpose, at the time of upshifting, a hydraulic pressure (QUPOFF) of a hydraulic engaging element on disengaging side is controlled such that the input and output speed ratio ("Gratio") of a transmission is decreased to, and held at, a predetermined slipping region (YG(N)S) that is lower than an engaging region (YG(N)L)-YG(N)H) to be set based on a gear ratio which is established by the engagement of the hydraulic engaging element on the disengaging side. The hydraulic pressure (QUPON) of a hydraulic engaging element on engaging side is gradually increased. When "Gratio" once falls below YG(N)L and then increases up again to YGCONOK, QUPOFF is lowered to a predetermined low pressure (QUPOFFB) at a lapse of a predetermined time (YTMUP8). Once "Gratio">YGCONOK, QUPON is increased to a predetermined high pressure QUPONB at a lapse of a second predetermined time YTMUP3.

Abstract: Both shocks and time lag at the time of gear-in are reduced. For that purpose, the hydraulic pressure of a hydraulic engaging element to be engaged at the time of gear-in (in-gear pressure) QING is increased relatively rapidly at the beginning of gear-in. The speed of increase of QING is lowered after the input and output speed ratio "Gratio" of a transmission has exceeded a predetermined value YINGS which works as a basis for discriminating the start of engagement of the hydraulic engaging element.

Abstract: Disclosed is a hydraulic control system for an automatic transmission including a plurality of friction elements associated with respective transmission speeds. The hydraulic control system includes a hydraulic fluid source, a line pressure controller, a reducing pressure controller, a range controller, a shift controller, a hydraulic pressure controller, and a hydraulic pressure distributor.

Abstract: Even if a rotational speed of an engine has already increased due to slipping of a fluid torque converter at the time of start of downshifting, a smooth downshifting is performed. For that purpose, there is obtained a speed change developing degree function K(etrm) of the rotational speed of the engine at the time of start of downshifting, the developing degree being dependent on an increase in the rotational speed of the engine due to slipping in the fluid torque converter. The function K(etrm) is obtained with a speed ratio "etrm" of the fluid torque converter at the time of starting of downshifting as a parameter. A boosting correction value QDNOFFZ is computed by multiplying a reference correction value QDNOFFZO by K(etrm) (step S108-5). The hydraulic pressure of the hydraulic engaging element on the disengaging side during downshifting is boosted by the amount of QDNOFFZ (step S108-6).

Abstract: It is detected on the basis of a change in an engine speed whether an out-of shelf condition in which a gear shft time exceeds a predetermined time is caused or not (step S11), and when the out-of shelf condition is caused, a lapping control processing corresponding to first engaging oil pressure setting means is executed so that a correction value is set to increase a line pressure supplied to each kind of engaging elements of an automatic transmission, and that the correction value is decreased as a gear shft load time elapses. At the same time, a learning control processing corresponding to a second engaging oil pressure setting means is executed (step S17) so that a variation of the engaging oil pressure due to the non-uniformity of engaging elements and the deterioration with age is learned, thereby to enable to automatically act a proper line pressure on each kind of engaging elements when either one of the automatic transmission or a controller which controls the automatic transmission is replaced.

Abstract: An apparatus for controlling the pressure of a hydraulically operated frictional coupling device which is released or engaged to achieve a shifting action of an automatic transmission, by first rapidly reducing or increasing the pressure to a predetermined level, holding the pressure at this level for a predetermined time and then continuously reducing or increasing the pressure to complete the shifting action, wherein a learning compensation device is provided to update, by learning compensation, a selected control parameter influencing a pattern of change of the pressure of the coupling device during the shifting action such that the shifting action is achieved in a predetermined manner.