Abstract: There are prevented shocks that will occur when a switchover speed changing is made to transfer from one speed changing, in the midst of that speed changing, to another speed changing when the input and output speed ratio "Gratio", which serves a control parameter, is not accurately detected. For that purpose, there is used a flag FGFAIL for setting "1" when the input and output speed ratio "Gratio", at the time of non-speed changing, does not lie within a predetermined range based on the gear ratio of the speed stage that is being established at that time. A switchover speed changing in which switching to another speed changing is made during a speed changing is prohibited when FGFAIL=1.

Abstract: Manual speed changing is performed in a shorter time without giving rise to shocks. For that purpose, at the time of manual speed changing, a hydraulic pressure QUPON of a hydraulic engaging element on the engaging side is corrected by boosting. A correction value QUPONX before starting of an inertia phase and a correction value QUPONY after starting of the inertia phase are separately set. By making QUPONX>QUPONY, the time required for manual speed changing as well as the shocks at the time of speed changing are reduced.

Abstract: Torque which is being transmitted by a clutch in the power train of a motor vehicle is regulated in response to processed signals from a control unit which receives signals denoting the driver's desire concerning the acceleration of the vehicle as well as numerous other variables including the position of the gas pedal, the RPM of the engine, the input and/or the output RPM of the transmission and others. The regulation is planned in such a way that the vehicle undergoes a higher than standard acceleration at the desired rate and that the thermal stressing of the clutch is minimized.

Abstract: The present invention prevents shift shock and reduces time required to execute the complete speed change operation in the case where a second speed change is commanded while a first speed change operation is still in progress. If a down-shift to a first speed stage is commanded during an up-shift operation from the first to the second speed, the hydraulic pressure in the second speed change operation is controlled in accordance with the state of the first speed change operation at the time of generation of the command for the second speed change. For example, if a down-shift to the first speed stage is commanded during the torque phase of an up-shift operation from first to second speeds, namely, before change in the rotational speed of the input shaft has started, only completion control of the down-shift operation is executed.

Abstract: When slipping is generated during the upshifting from a first gear shift stage to a second gear shift stage on ice or the like, a control for prohibiting the upshifting from the second gear shift stage to a third gear shift stage can be carried out precisely. A control system is designed so that when a slipping state is detected on ice having a lower road surface friction coefficient by a slipping state determining device, the upshifting of an automatic transmission from a second gear shift stage to a third gear shift stage is prohibited. In this control system, the time required for the upshifting from a first gear shift stage to the second gear shift stage is measured. If such time is shorter than a first predetermined time, it is determined that a slipping has been generated during the upshifting, and the upshifting from the second gear shift stage to the third gear shift stage is prohibited for a second predetermined time.

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: If a shift to the 3rd speed is decided during the 5th-4th speed shift, in which the hydraulic servo for a second clutch is released by pressure regulation control, a changeover valve is switched by a solenoid valve so that the fluid pressure P.sub.C2 from the pressure regulating valve is conducted to a third clutch hydraulic servo. Thereby, the third clutch hydraulic servo pressure P.sub.C3 stands by at a predetermined engaging pressure P.sub.H and, at the same time, the servo-start of a fourth brake fluid pressure P.sub.B4 is performed by another pressure regulating valve. Meanwhile, the fluid pressure P.sub.C2 is released by an accumulator. After the servo-start ends and the 4th speed is established, the 4-3 speed shift control is performed, thus preventing shift shock and reducing shift duration.

Abstract: A method of controlling and regulating an automatic transmission with overlapping gearshifts. The change from the control mode to the regulating mode for the disengaging clutch (11) is made here when a defective engagement of the engaging clutch (12) is detected.

Abstract: A method and system for controlling shift in an automatic transmission that can establish a plurality of gear ratios by selectively supplying a hydraulic pressure for a plurality of frictional engaging elements.

Abstract: A shift control method for an automotive automatic transmission is provided, which reduces a shift shock particularly at the time of a skip down-shift, and shortens a required shifting time period. An electronic control unit of a shift control apparatus releases the engagement of a clutch of a subsidiary transmission mechanism and engages a one-way clutch so as to establish a gear position not used in the normal speed change when a shift command from the fifth shift position to the third shift position is issued, gradually decreasing a valve opening duty ratio of an electromagnetic valve associated with a brake of a main transmission mechanism from an initial value D.sub.HLi before this gear position is established, determines an average turbine rotation speed changing rate dD.sub.TAVE /dt from the detected turbine rotation speed (S203), and learning correction of the initial value D.sub.HLi is made if the changing rate deviates from a target range (S204-S208).

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. 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: An up-shift control apparatus includes an engine racing detecting means for detecting engine racing during an up-shift and an engine racing preventing means. The up-shift control apparatus is installed to an automatic transmission which executes the up-shift by disengaging a first friction element and by engaging a second friction element. The engine racing preventing means outputs a command signal to a valve actuator to temporally increase an engagement force of the first friction element when the engine racing is detected during the up-shift.

Abstract: A gear shift control apparatus for use in an automatic transmission having friction elements each of which is operable on a working fluid pressure applied thereto in an engaged and released state. A change is produced from the current gear ratio to a desired gear ratio by increasing the pressure of the working fluid to a first one of the friction elements at a first rate to engage the first friction element while decreasing the pressure of the working fluid to a second one of the friction elements at a second rate to release the second friction element. A time elapsed for a torque phase in the gear ratio change is measured. The first rate is decreased when the measured torque phase time is shorter than a predetermined value. The second rate is increased when the measured torque phase time is longer than the predetermined value.

Abstract: In the vehicle equipped with an ABS, a control system for reducing stopping distance in an abrupt braking operation and a method thereof includes an idle sensor for detecting an operating state of an accelerator pedal; a brake sensor for detecting an operating state of a brake pedal; a brake operation sensor for detecting an angle change of a brake pedal to output an electric signal corresponding thereto; an engine RPM sensor for detecting a rotation number of a crank gear to output an electric signal corresponding thereto, the sensor being equipped on an engine crank shaft and rotated by driving engine; a transmission control unit which when a power source is applied to the vehicle and the idle switch and the brake switch is worked, detects the angle change per hour of the brake pedal and then if the brake angle change is over the predetermined one, determines that as an abrupt braking state, and further detects the shift range set up by the operation of the shift lever as well as the current shift stage in

Abstract: A controller (100 in FIG. 1) for relieving a gear shift shock in a vehicle, comprising an input torque calculation portion (131) which calculates the input torque (T.sub.t) of the stepped automatic transmission mechanism of the vehicle from engine r.p.m. (N.sub.e) and turbine r.p.m. (N.sub.e), a shift start recognition portion (134) which recognizes the real mechanical shift start timing of the stepped automatic transmission mechanism in accordance with the change of the input torque (T.sub.t), a line-pressure correction magnitude calculation portion (142) which calculates a line-pressure correction magnitude (.DELTA.PL) during the gear shift operation of the stepped automatic transmission mechanism when the shift start has been recognized, a standard line pressure calculation portion (143) which calculates a standard line pressure (PL), and a command line pressure calculation portion (144) which adds the line-pressure correction magnitude (.DELTA.

Abstract: A speed change control apparatus for an automatic transmission includes a transmission control unit for controlling gear-changing. The control unit discriminates a fluid temperature/rotational speed zone based on the hydraulic fluid temperature and the engine speed at the start of gear-changing, and detects a time period from the end of dead-stroke elimination of an engagement-side hydraulic clutch to the start of actual gear-changing. In the case that a condition for executing learning correction is satisfied and if a time period from the end of the dead-stroke elimination to the start of the actual gear-changing is longer than an upper limit, the control unit increases a learning-correction time with which a dead-stroke-elimination time for the discriminated temperature/speed zone is calculated. The learning-correction time is decreased if such a time period is shorter than a lower limit.

Abstract: An apparatus for controlling an automatic transmission including hydraulic friction elements each of which is operable between engaged and disengaged positions in response to a working pressure of hydraulic fluid supplied thereto so as to produce a selected one of a plurality of modes of gear change. The control apparatus is operable through successive operating modes including a precharge mode of precharging the hydraulic fluid to a corresponding one of the friction elements to complete a loss stroke of the friction element, a critical pressure retaining mode of retaining the working pressure at a critical value and a feedback control mode of controlling the working pressure. A different of the rate of change of the friction element input side speed sensed during the critical pressure retaining mode from the average rate of change of the friction element input side speed sensed during the precharge mode is calculated.

Abstract: The apparatus comprises a planetary gear device and a magnetic particle type electromagnet clutch. The planetary gear device has a gear element connected to an input member, another gear element connected to an output member and a remaining other gear element. The electromagnetic clutch has a fixed member provided with a exciting coil and a rotary member adapted to be fixed to the fixed member by controlling intensity of electric current in the exciting coil. The rotary member is connected to the remaining other gear element.

Abstract: A shift control method for executing a shift-up control from an off-going range to an on-coming range comprises an off-going-range releasing stage, an off-going-range controlling stage, and an on-coming-range invalid-stroke-clearing stage. In the off-going-range releasing stage, a pressure command signal is generated to quickly lower the engagement-actuation pressure of the off-going engaging element. In the off-going-range controlling stage, a pressure command signal is generated to control the engagement-actuation pressure of the off-going engaging element in such a way that the off-going engaging element is kept slipping within a predetermined range of input/output rotational speed ratio (=output rotational speed/input rotational speed).

Abstract: A system for controlling a vehicle automatic transmission, in which a gear ratio to be shifted to is determined based on the vehicle speed and throttle opening degree and a clutch is supplied with hydraulic pressure such that the rotational speed of the transmission input shaft concurs with a desired rotational speed change rate. The system includes means for discriminating whether the engine load fluctuates and the operation is discontinued when it is discriminated that the engine load fluctuates. Specifically, even when the accelerator pedal is operated only somewhat rapidly and the engine output is able to follow the change in the degree of throttle opening, the degree of throttle opening nevertheless differs between that at the start of gearshift and that in the course of gearshift thereafter, causing unexpected gearshift shock to occur. The arrangement can solve the problem.

Abstract: A control for an automatic transmission minimizes shift cycling between adjacent speed ratios due to non-ideal load conditions such as grade climbing and trailering. The control utilizes shift schedule data in formulating a determination of the ability of the vehicle to maintain current levels of performance if an upshift were to occur and inhibits such upshifts where the determination so indicates an inability to meet the criteria.

Abstract: A shift control system for an automatic is designed to prevent engine racing and clutch tie-up during a clutch-to-clutch shift (clutch switching shift) involving engagement/disengagement of first and second frictional engagement elements. The shift control system includes an engagement force controller for independently controlling both of the frictional engagement elements. A gear ratio calculator continuously calculates a gear ratio r of the transmission and a shift characteristic value calculator calculates a shift characteristic value .alpha. based on changes in the gear ratio between the start of the shift and completion of the shift. A control value calculator calculates a control value .beta., based on the shift characteristic value .alpha. calculated by the shift characteristic value calculator and a shift characteristic value .alpha.I on an ideal gear ratio curve. The control value .beta. is calculated so that the shift characteristic value .alpha. coincides with the shift characteristic value .

Abstract: A control unit 11b which consists of a microcomputer compensates the detected intake manifold pressure Pb with an atmospheric pressure, obtains a first estimated position of the throttle when the amount of by-pass air is null and a second estimated position of the throttle when the mount of by-pass air is the maximum from the intake manifold pressure compensated with the atmospheric pressure and the detected revolution speed Ne, obtains the ratio of the amount of by-pass air currently under control to the maximum controllable amount of by-pass air, estimates the position of the throttle from the ratio and the first and second estimated positions of the throttle, and collates the estimated position of the throttle after compensation and the detected vehicle speed V.sub.s with the speed change map to shift the gear of the automatic transmission 3.

Abstract: A shift control system of an automatic transmission controls operating forces on frictional engaging elements being engaged and disengaged with gear elements during a shift operation by generating a target transmission variable which prevents a rate of change of a corresponding target input rotational speed from inverting at the start of the shift operation and/or at the end of the shift operation. The target transmission variable may be the target input rotational speed, a target gear ratio, or other variable corresponding to a target input rotational speed which has a rate of change gradually changing at the start and end of the shift operation so as to avoid any inversion of the rate of change within a predetermined duration after the start of the shift operation and within a predetermined duration before the end of the shift operation.

Abstract: In a hydraulic control system for automatic transmissions of a vehicle, drive pressure is fed to a first friction member at the first, second and third speeds of a "D" range, drive pressure is fed to a third friction member at a fourth speed, a 2-4/3-4 shift valve for exhausting pressure from the first friction member at third-to-fourth and second-to-fourth speed shifting is connected to an end clutch valve to allow pressure from a first pressure control valve to be fed to the third friction member at the fourth speed, and exhausting of pressure from a releasing conduit of a second friction member and the third friction member via an exhaust conduit connecting the 2-4/3-4 shift valve and a 2-3/4-3 shift valve during fourth-to-second, fourth-to-first and third-to-second speed shifting is delayed by an orifice.

Abstract: A method for the control of a gear change of an automatic discrete step gearbox of a motor vehicle superimposes a regulation of the gearbox input rotational speed during a rotational speed adaptation phase on a control of the transmission torque of a frictional connection. A required deceleration value is specified as a function of a deceleration torque to be brought about by the frictional connection.

Abstract: A motor vehicle shift control apparatus wherein two hydraulically operated frictional coupling devices are simultaneously released and engaged, respectively, to effect a clutch-to-clutch shift of an automatic transmission, including an overshoot control device for compensating the hydraulic pressure of at least one of the coupling devices during the clutch-to-clutch shift such that the amount of engine speed overshoot is held within a predetermined range, and an inhibiting device for inhibiting an operation of the overshoot control device if a preventing device for preventing an excessive rise of the engine speed above an upper limit is expected to be activated, or if the preventing device is in operation. The inhibiting device may be replaced by a device for reducing the output of the engine if the engine speed is higher than a threshold not higher than the upper limit.

Abstract: A control system for an automatic transmission for a vehicle provides an enhancement in a shifting characteristic in a manually shifting mode by controlling an operating hydraulic pressure for hydraulic engage elements in an appropriate manner. In a first range from the output of a shifting command to a time point when a timer TOIPU reaches a counting-up value, or a time point when the slip rate ECL of the hydraulic engage elements exceeds a value YECLIPUS, the operating hydraulic pressure is set at a preset value depending upon the type of shifting. In a second range from the end of the first range to a time point when the timer TOIPU reaches a counting-up value, or a time point when a slip rate ECL exceeds a value TECLIPUS, and in a third range from the end of the second range to a time point when a timer TKAK reaches a counting-up value, the operating hydraulic pressure QAT is set at a value corresponding to an engine torque or a transmission input torque.

Abstract: An apparatus for controlling an automatic transmission of a motor vehicle wherein two hydraulically operated frictional coupling devices are released and engaged, respectively, to effect a clutch-to-clutch shift-up action of the transmission, and a shift-up boundary line for determining whether the shift-up action should take place is compensated by a learning shift-point compensating device, so as to prevent a rise of the vehicle engine above an upper limit during the shift-up action effected according to the compensated shift-up boundary line, the apparatus including an inhibiting device for inhibiting an operation of the learning shift-point compensating device if an amount of overshoot of the engine speed detected during the shift-up action is larger than a predetermined threshold.

Abstract: A shift control system can perform clutch-to-clutch shifts without occurrence of delay in shifting operation and aggravation of shift shock, by decreasing an engaging force of a first frictional engagement device and increasing an engaging force of a second frictional engagement device, and comprises a low pressure retention instructer for maintaining the second frictional engagement device at a predetermined low level until a revolution speed of a rotary member reaches a predetermined value upon the shift, an engagement instructer for increasing the engaging force of the second frictional engagement device after the revolution speed of the rotary member has reached said predetermined value, and a pressure rise instructer for increasing the engaging force of the first frictional engagement device after increasing the engaging force of the second frictional engagement device.

Abstract: The present invention provides a sensing system and method for providing information relating to a drivetrain during shifting operations. The drivetrain includes an engine, a torque converter and a transmission. The system includes sensors for detecting the output speed of the engine, the output speed of the torque converter, and the output speed of the transmission. The system detects the starting condition of a shifting operation, responsively determines a set of performance parameters, and produces a set of performance parameter signals.

Abstract: The present invention is directed toward determining when a clutch of an automatic transmission substantially fills with fluid. Once it is accurately determined when a clutch fills with fluid, then control over the transmission shifting may reliably be performed. The present invention determines when an on-coming speed clutch substantially fills with fluid in response to determining when an off-going speed clutch releases. Further, the present invention determines when an on-coming direction clutch substantially fills with fluid in response to determining when the torque converter output torque suddenly changes.

Abstract: An electronically controlled arrangement for changing the transmission ratio of a speed-change gearbox of a drive assembly of a motor vehicle, in which a change with the effect of changing-up is prevented by an inhibiting signal formed as a function of parameters of the control of the drive assembly or of the driving state. The change is re-authorized when the accelerator pedal again reaches a significant position determined by a change in level of the inhibiting signal and when a delay time determined by the actuation of the accelerator pedal has elapsed.

Abstract: A control system (104)/method for a vehicular automated mechanical transmission is provided, which will compare input signals indicative of input shaft speed (IS) to the product of input signals indicative of output shaft speed multiplied by engaged gear ratio (OS*GR) to develop control parameters indicative of drivetrain torque magnitude and/or phase requiring a driveline torque transducer.

Abstract: An automatic transmission of a vehicle including a speed change gear mechanism including rotary members such as gears and gear carriers and hydraulically operated friction engaging means and adapted to provide various speed stages according to selective engagement and disengagement of the friction engaging means is controlled by such steps as detecting rotation speed of at least one of the rotary members during a shifting between the speed stages, changing hydraulic pressure of at least one of the friction engaging means during a first phase of the speed stage shifting so as to make the rotation speed of the one rotary member follow a first change performance curve calculated according to a first feedback control program, and changing the hydraulic pressure of the one friction engaging means during a second phase of the speed stage shifting so as to make the rotation speed of the one rotary member follow a second change performance curve calculated according to a second feedback control program in continuity

Abstract: In one aspect of the present invention, an electronic shift control for a powershift transmission is disclosed. The transmission includes a plurality of speed and direction changing clutches. A plurality of pressure control valves are individually connected to the clutches. A hydraulic pump delivers pressurized hydraulic oil to predetermined pressure control valves to meter hydraulic fluid in response to receiving a clutch command signal. The method produces a shift from a first transmission ratio to a second transmission ratio through disengagement of an off-going clutch associated with the first transmission ratio and engagement of an on-coming clutch associated the second transmission ratio. The method includes filing an on-coming speed clutch, releasing an off-going direction clutch in response to the on-coming speed clutch being filled, and thereafter, gradually increasing the on-coming speed clutch pressure to engage the speed clutch.

Abstract: The present invention provides a method of adaptively modifying the transmission shift schedule during various driving conditions. The method determines a desirable upshift schedule based upon driving conditions, and adaptively adjusts the transmission shift schedule in accordance with a predefined criteria. This is accomplished by observing vehicle speed and other transmission operating parameters and determining whether an adaptive shift schedule adjustment is required. If the shift schedule is adaptively adjusted, the driving parameters are further monitored to determine at which time the shift schedule may be reset to its initial state.

Abstract: An automatic transmission shift control system calibrates a locking speed, which is regulated by a regulating valve and at which locking of a specific frictional element is performed so as to shift an transmission gear mechanism to a specific gear, in accordance with a deviation of an input speed of rotation to the transmission from a specified input speed of rotation while shifting the transmission to the specific gear. The system further varies the calibration according to a transitional period of time which is defined from a completion of shifting to a preceding gear from which the transmission is shifted directly to the specific gear to a commencement of shifting to the specific gear subsequently to the shifting to the preceding gear.

Abstract: The present invention provides improved initial shift quality in an electronically controlled automatic transmission by enabling the friction element fill volumes to be "learned" by the transmission controller before the vehicle leaves the assembly line. An end of line (EOL) volume learn procedure is intended for final check out at car assembly or for other appropriate circumstances such as for service after a transaxle has been rebuilt or replaced, or as a diagnostic tool to help confirm an indicated condition of an element.Upon satisfaction of a set of initial conditions, an end of line volume learn procedure is initiated wherein the transmission is cycled through a number of phases, each phase generally corresponding to the application of a different friction element.

Abstract: An automatic transmission on an automobile has an input shaft, an output shaft, a plurality of power transmitting paths disposed between the input and output shafts for establishing respective gear positions, and a plurality of engaging elements for selecting one of the power transmitting paths at a time. A shift controller disengages a previous-position engaging element and engages a next-position engaging element to switch from one of the power transmitting paths to another for thereby effecting a shift from a previous gear position to a next gear position.

Abstract: A reengagement control system/method (200) for a semi-automatic mechanical transmission system (104) of the type requiring manual synchronization of the transmission to enable automatic implementation of a selected shift into a target gear ratio is provided. The reengagement control will cause immediate engagement of an engageable ratio, based upon vehicle speed, if the transmission is shifted to neutral and is then unable to engage in the target gear for greater than a predetermined time (REF.sub.2) as vehicle acceleration (dOS/dt) exceeds an acceleration reference value (REF.sub.1).

Abstract: During downshift operation of an automotive automatic transmission in which a lower-speed clutch for establishing a lower-speed gear is engaged while higher-speed clutch, which has established a higher-speed gear, is disengaged, to increase the turbine rotational speed Nt toward a synchronous rotation speed Ntj associated with the lower-speed gear, speed change control is carried out according to the same control method regardless of whether the engine is in a power-on or power-off state. A target change rate (Nir)' of turbine rotational speed associated with the higher-speed clutch and a target change rate (Nia)' of turbine rotational speed associated with the lower-speed clutch are set, and a change rate (Nia)' of the turbine rotational speed is detected. The transmission torque through the higher-speed clutch is controlled in a feedback manner such that the detected change rate (Nt)' coincides with the change rate (Nir)'.

Abstract: An improved adaptive transmission pressure control in which cumulative adaptive corrections are stored in a multi-cell memory array, the cells being associated with specified contiguous ranges of a vehicle operating parameter, such as engine throttle position. Periodically determined adaptive correction amounts are applied to a selected cell which includes the engine throttle setting measured at the initiation of the shift and to two or more cells associated with contiguous engine throttle ranges. In this way, a relatively large number of cells may be employed to minimize approximation errors, while maintaining a cell-to-cell continuum of pressure correction values. In operation, an electro-hydraulic pressure regulator is controlled as a combined function of a predefined pressure command obtained from a normal table look-up and a cumulative correction amount obtained from the memory array.

Abstract: An automotive automatic transmission has a hydraulically operated clutch device and an electronic control unit. The clutch device includes drive and driven clutch plates and a piston for pressing the drive and driven clutch plates to establish an engagement therebetween when an oil chamber for the piston is fed with a certain amount of fluid. In order to control the clutch device, the following steps are employed, which are (a) issuing a first instruction signal to the clutch device; (b) feeding the oil chamber with the fluid by an amount which is sufficient for moving the piston from a rest position to a critical position which is ready for effecting the actual pressure against the drive and driven clutch plates; (c) issuing a second instruction signal to the clutch device; and (d) increasing the hydraulic pressure in the oil chamber to cause the piston to instantly establish the engagement between the drive and driven clutch plates.

Abstract: A control system is provided for servo hydraulic pressure in an automatic transmission. Upon downshifting, one of first and second frictional engagement devices is released while the other is engaged. A directional control valve is provided to feed or drain servo hydraulic pressure to selectively engage or release the first and second devices. The hydraulic pressure is regulated by a pressure regulator under the control of an electronic control unit. Detectors are also provided to determine input rotation and torque, respectively. The regulator is interposed between the directional control valve and the engaged device. The regulator is controlled to maintain the servo hydraulic pressure at a predetermined value under the control of the electronic control unit until predetermined input rotation is detected and then to gradually raise the servo hydraulic pressure under the control of the electronic control on the basis of the value of input torque.

Abstract: A control system for controlling an automotive automatic transmission which comprises a friction element operated by a hydraulic pressure. The control system comprises a first device for judging whether a gear change of the transmission is necessary or not in accordance with the running condition of the vehicle; a second device for lowering the hydraulic pressure when the first device judges a necessity of the gear change; a third device for increasing the hydraulic pressure when a difference between the maximum engine speed appearing after starting of gear change operation and a current engine speed is greater than a predetermined degree; and a fourth device for increasing the hydraulic pressure when a predetermined time passes from the time when the first device has judged the necessity of the gear change irrespective of operation of the third device.

Abstract: A control device of a transmission fluid pressure for an electronically controlled automatic transmission comprising: a rotational number change detecting means for detecting a rotational number change of either an engine or a rotational member of an automatic transmission; a transmission fluid pressure controlling means for arbitrarily controlling a transmission fluid pressure for a transmission fluid pressure controlling device of the automatic transmission; and a control device for controlling a target value of the transmission fluid pressure for the transmission fluid pressure controlling device by a negative feed back control dependent at least on the rotational number change of either the engine or the rotational member of the automatic transmission, said control device determining whether the engine is in a constant speed or acceleration mode, and temporarily discontinuing the negative feed back control or reducing a control quantity thereof when the engine shifts from a deceleration/closed throttle mo

Abstract: A particular engine control system is used with an engine equipped with an automatic transmission. The automatic transmission is changeable between an economy operation mode, in which the automatic transmission is placed more frequently in higher gears so as to create a travel mode giving priority to fuel economy, and a power operation mode, in which the automatic transmission is placed more frequently in lower gears so as to create a travel mode giving priority to powerful running. The system controls the engine so as to provide a gentle increase in engine output in the economy mode.

Abstract: A process is described for controlling the actuating pressure in a control element (shift element) of an electrohydraulically controlled transmission of a motor vehicle during a change of the gear position. In the case of downshifts in the coasting operation, the hydraulic pressure in the transmission is preferably increased with the initiating of the shifting by way of the pressure control valve in a time-limited manner. Starting from a presettable or preset basic value, the amount of this filling pulse is automatically and in steps for each control operation in the course of the operation of the transmission adapted to a target value in such a manner that an input rotational speed of the transmission or a rotational speed of a driving engine connected in front of the transmission follows a predetermined sequence of movements.

Abstract: A particular shift control system is provided for an automatic transmission having a primary transmission, changeable to at least three primary gear ratios, and a secondary transmission, changeable to at least two secondary gear ratios. The primary and secondary transmissions combine to shift the automatic transmission to a plurality of forward speeds. The control system monitors the progression of change in the primary transmission gear ratio. In a specific automotive drive condition, the primary transmission changes from one primary gear ratio to another primary gear ratio via an intermediate primary gear ratio between the two primary gear ratios. This produces an increase or decrease in a primary gear ratio. At the same time, the secondary transmission decreases or increases, respectively, a secondary gear ratio so as to shift the automatic transmission from one forward speed to another, skipping an intermediate speed between the two forward speeds.