Abstract: Inventive embodiments are directed to components, subassemblies, systems, and/or methods for continuously variable transmissions (CVT). In one embodiment, a main axle is adapted to receive a shift rod that cooperates with a shift rod nut to actuate a ratio change in a CVT. In another embodiment, an axial force generating mechanism can include a torsion spring, a traction ring adapted to receive the torsion spring, and a roller cage retainer configured to cooperate with the traction ring to house the torsion spring. Various inventive idler-and-shift-cam assemblies can be used to facilitate shifting the ratio of a CVT. Embodiments of a hub shell and a hub cover are adapted to house components of a CVT and, in some embodiments, to cooperate with other components of the CVT to support operation and/or functionality of the CVT. Among other things, shift control interfaces and braking features for a CVT are disclosed.

Abstract: A vehicle includes a multi-speed transmission having an input shaft and an output shaft, an actuator, and a torque converter having an impeller selectively coupled to the actuator and a turbine coupled to the input shaft. A vehicle controller is programmed to, in response to an estimated torque ratio between the impeller and output shaft of the transmission being less than a minimum torque ratio between the impeller and output shaft of the transmission during a shift of the transmission, command torque to the actuator based on a driver-demanded wheel torque and the minimum torque ratio, and, in response to the estimated torque ratio exceeding the minimum torque ratio during the shift of the transmission, command another torque to the actuator based on the driver-demanded wheel torque and the estimated torque ratio.

Abstract: A hydraulic control circuit for a drive line includes first and second switching valves and first and second solenoid valves. Each switching valve is alternatively switched by a switching hydraulic pressure to connect any two of three ports. The first port of the first switching valve is connected to a hydraulic actuator. The first port of the second switching valve is connected to the second port of the first switching valve. The first solenoid valve supplies the switching hydraulic pressure to the switching valves. The second solenoid valve regulates a control hydraulic pressure supplied to the hydraulic actuator. Any one of three oil paths is communicated with the hydraulic actuator by supplying the control hydraulic pressure via the third port of the first switching valve or the second or third port of the second switching valve and supplying the switching hydraulic pressure to at least one switching valve.

Abstract: A multiple ratio transmission having an input shaft, an output shaft and oncoming clutch and off-going clutch for effecting ratio upshifts is provided. The transmission also includes a transmission controller configured for controlling shifts. During the torque phase of a ratio upshift, the controller increases input torque. Next, the controller estimates an oncoming clutch target torque. The controller controls a torque input to ensure the off-going clutch remains locked. The controller measures an actual transmission value for a torque transmitting element of the transmission and corrects the oncoming clutch target torque using the actual transmission value whereby an increasing torque for the oncoming friction element is achieved with minimal torque transients along the output shaft during the upshift.

Abstract: A method of maintaining a substantially stable engine speed after a garage shift of an automatic transmission includes identifying a moment when a load from the automatic transmission is applied to an engine via a torque converter during the garage shift based on a first turbine speed change with respect to a reference engine speed change and a second turbine speed change with respect to an actual engine speed change. The method further includes generating a feed forward torque command based on a turbine speed decrement after identifying the moment when the load from the automatic transmission is applied to the engine, and controlling the engine based on the feed forward torque command to maintain a substantially stable engine speed after the garage shift.

Abstract: A method of controlling a pump for a hybrid transmission includes commanding a first line pressure of the transmission and deriving a first torque value—an open-loop torque value—from the first line pressure command, and commanding the pump to operate at the first torque value. The method monitors actual speed of the pump and derives a second torque value—a closed-loop torque value—therefrom. A third torque value is derived from the first and second torque values, and the pump commanded to operate at the third torque value. A first speed value may be derived from the first line pressure command, and the second torque value derived from the difference between the monitored and the first speed values. Deriving the third torque value may include a substantially-linear combination of the first and second torque values.

Abstract: There is disclosed a continuously variable ratio transmission assembly (“variator”) comprising a roller which transmits drive between a pair of races, the roller being movable in accordance with changes in variator ratio, a hydraulic actuator which applies a biasing force to the roller, at least one valve connected to the actuator through a hydraulic line to control pressure applied to the actuator and so to control the biasing force, and an electronic control which determines the required biasing force and sets the valve accordingly, wherein the valve setting is additionally dependent upon a rate of flow in the hydraulic line.

Abstract: A transmission and control method are disclosed which ensure proper stroke pressure and minimize torque transients during a shift event. The transmission includes a clutch having a torque capacity based on a fluid pressure, a torque sensor adapted to measure a torque value that varies in relationship to the torque capacity, and a controller. The method includes varying the fluid pressure around a predetermined value, measuring a resulting torque difference with the torque sensor, and adjusting a clutch control parameter if the resulting torque difference is less than a threshold value.

Abstract: A method for an automatic transmission includes measuring torque of a component of the transmission using a torque sensor in communication with the component. The torque of the component is estimated from information other than the measured torque. The measured torque is rejected from being used in a control operation of the transmission if the difference between the measured torque and the estimated torque is greater than a selected threshold.

Abstract: A multiple ratio transmission having an input shaft, an output shaft and oncoming clutch and off-going clutch for effecting ratio upshifts is provided. The transmission also includes a transmission controller configured for controlling shifts. During the torque phase of a ratio upshift, the controller increases input torque. Next, the controller estimates an oncoming clutch target torque. The controller controls a torque input to ensure the off-going clutch remains locked. The controller measures an actual transmission value for a torque transmitting element of the transmission and corrects the oncoming clutch target torque using the actual transmission value whereby an increasing torque for the oncoming friction element is achieved with minimal torque transients along the output shaft during the upshift.

Abstract: Methods and apparatus for sealing a puncture or incision formed percutaneously in tissue separating two internal portions of the body of a living being with an anchor, a sealing plug and a filament connecting the anchor and sealing plug are disclosed. The methods and apparatus provide for automatic tamping of the sealing plug. In addition, torque required to tamp the sealing plug is automatically sensed and gear ratios of an automatic tamping device are automatically changed in response to sensed changes in torque. A planetary transmission may be used to automatically change gear ratios in response to the changes in torque.

Abstract: A powertrain includes a torque generative device and a torque converter having an impeller, a turbine and a torque converter clutch. A method to control torque converter slip includes monitoring a reference slip and a turbine speed of the torque converter, determining a turbine torque based upon the reference slip and the turbine speed, determining a feed forward torque converter clutch pressure command based upon the turbine torque, a torque generative device torque, and a TCC gain, and controlling the torque converter clutch based upon the feed forward torque converter clutch pressure command.

Abstract: An in-gear oil pressure correcting section corrects engagement control oil pressure set up by an oil pressure supply control section over the entire range to be reduced by first predetermined pressure. An engagement determining section determines, on the basis of a torque converter slip ratio calculated by a calculating section, whether a frictional engagement element of a destination gear starts to engage or not. An addition correcting control section corrects the corrected engagement control oil pressure to add second predetermined pressure thereto in the case where engagement of the frictional engagement element has not been started yet when a timer measures first predetermined time. The addition correcting control section further corrects the corrected engagement control oil pressure to add third predetermined pressure thereto in the case where the engagement of the frictional engagement element has not been started yet when the timer measures second predetermined time.

Abstract: A method for operating a motor vehicle hybrid powertrain having an engine, a motor-generator and a multi-speed automatically-shiftable transmission, wherein the engine and the motor-generator operate to supply torque to the transmission for driving a vehicle. The method includes modulating the torque supply from the motor-generator to the transmission during a gear shift to minimize a transmission output torque disturbance.

Abstract: A method of controlling output torque in a hybrid or electric vehicle transmissions includes calculating a first long-term output torque constraint and a first short-term output torque constraint. A first effective output torque constraint is determined from at least one of the first long-term and short-term output torque constraints. The first effective output torque constraint is bounded by both of the first long-term and short-term output torque constraints. The method may further include calculating a rate limit, such that determining the first effective output torque constraint includes restricting the magnitude of changes in the first long-term output torque constraint to the calculated rate limit. A spread between the first short-term output torque constraint and the first effective output torque constraint may be measured, and the rate limit calculated as a function of that spread. The rate limit may also be calculated with an inversely-proportional relationship to the spread.

Abstract: During control of a shift of a first friction engagement element from an engaged state into a disengaged state and a shift of a second friction engagement element from a disengaged state into an engaged state for a gear shift to a first target gear from a second target gear, a desired torque capacity of the first friction engagement element is set based on an actual transmission gear ratio by interpolation from values of the desired torque capacity corresponding to at least first and second reference transmission gear ratios, wherein the first reference transmission gear ratio is a transmission gear ratio at start of an inertia phase of the shift control. When the first reference transmission gear ratio is between the actual transmission gear ratio and the second reference transmission gear ratio, the desired torque capacity is set to the value corresponding to the first reference transmission gear ratio.

Abstract: A shift control apparatus that disconnects and connects respective pairs of friction engagement elements during downshift to a speed spaced apart by two or more steps through an intermediate shift speed. A shift controller controls a hydraulic pressure of a second shift release element by feedback control, and in accordance with the increase in the torque capacity of the second shift release element, also controls the torque capacity of a first shift engagement element so as to be sufficiently higher than the amount of change in the torque capacity of the second shift release element. The occurrence of adverse consequences in which a shift shock is generated is effectively suppressed because a sufficient reaction force cannot be ensured during engagement switching due to insufficient torque capacity of the first shift engagement element, and since the second shift release element cannot be appropriately feedback-controlled, difficulty in control of rotation change results.

Abstract: Methods and apparatus for sealing a puncture or incision formed percutaneously in tissue separating two internal portions of the body of a living being with an anchor, a sealing plug and a filament connecting the anchor and sealing plug are disclosed. The methods and apparatus provide for automatic tamping of the sealing plug. In addition, torque required to tamp the sealing plug is automatically sensed and gear ratios of an automatic tamping device are automatically changed in response to sensed changes in torque. A planetary transmission may be used to automatically change gear ratios in response to the changes in torque.

Abstract: The adjustment method includes an estimation step in which valve characteristics of the linear solenoid valves fitted to the hydraulic control circuit are measured, and estimated linear valve characteristics of the linear solenoid valves in isolation state are estimated based on the measured valve characteristics using predetermined correlations; and a correction value output step in which estimated linear piston-end pressures of the hydraulically-driven friction engagement elements immediately before the hydraulically-driven friction engagement elements are engaged are calculated based on the estimated linear valve characteristics, and the correction values that are applied to the control command values to adjust the drive currents supplied from the valve control unit to the linear solenoid valves are calculated based on differences between the estimated linear piston-end pressures and nominal piston-end pressures, and then output.

Abstract: A control system for a vehicle having first and second wheels is provided that includes a differential apparatus adapted to distribute torque between the first and second wheels and a traction controller for controlling operation of the differential apparatus from vehicle launch up to a predetermined vehicle speed. The traction controller is configured to engage the differential apparatus in a first operating state according to at least one vehicle operating parameter indicative of a low traction operating condition and to further control engagement of the differential apparatus in a second vehicle operating state during the low traction operating condition according to a difference between an actual vehicle yaw rate and a predetermined target vehicle yaw rate. The control system also includes a stability controller for controlling engagement of the differential apparatus at or above the predetermined vehicle speed.

Abstract: A drive unit includes an engine and a transmission having a variable transmission ratio. An instantaneous setpoint power output quantity of the drive unit is determined from an intended power output. The setpoint power output quantity is a function of the instantaneous transmission ratio of the transmission at least for a given intended power output.

Abstract: Strain gauges and a torque value calculating unit detect a value for torque acting on a sun gear, based on a reaction force. A torque phase detecting unit detects start of a torque phase at which only torque distribution changes while a gear ratio stays at the same level as before upshift, based on a change in the value for torque detected by the strain gauges and the torque value calculating unit. Consequently, when upshifting, an end of a piston stroke can be accurately determined by precisely detecting the torque phase during the shifting. Thus, problems such as burning of friction materials due to excessive heat generation in friction engagement elements can be eliminated.

Abstract: There is provided a control system for electro-mechanical transmission that is selectively operative in a plurality of fixed gear modes and continuously variable modes comprising first and second electrical machines and four hydraulically-actuated clutches in fluid communication with a hydraulic circuit comprising first, second and third pressure control devices and first and second flow management valves. The control system is operative to selectively actuate the pressure control devices and the flow management valves based upon a demand for torque, presence of a fault, and temperatures of the electric machines.

Abstract: A drive system for a work machine is disclosed. The drive system has at least one driven traction device and a transmission operatively connected to the at least one driven traction device. The transmission is configured to drive the at least one driven traction device. The drive system further has a controller configured to determine a ground tractive capacity associated with the at least one driven traction device and to limit an amount of torque transmitted from the transmission to the at least one driven traction device when the amount of torque to be transmitted will exceed the ground tractive capacity.

Abstract: There is provided a control system for electro-mechanical transmission that is selectively operative in a plurality of fixed gear modes and continuously variable modes comprising first and second electrical machines and four hydraulically-actuated clutches in fluid communication with a hydraulic circuit comprising first, second and third pressure control devices and first and second flow management valves. The control system is operative to selectively actuate the pressure control devices and the flow management valves based upon a demand for torque, presence of a fault, and temperatures of the electric machines.

Abstract: Methods and apparatus for sealing a puncture or incision formed percutaneously in tissue separating two internal portions of the body of a living being with an anchor, a sealing plug and a filament connecting the anchor and sealing plug are disclosed. The methods and apparatus provide for automatic tamping of the sealing plug. In addition, torque required to tamp the sealing plug is automatically sensed and gear ratios of an automatic tamping device are automatically changed in response to sensed changes in torque. A planetary transmission may be used to automatically change gear ratios in response to the changes in torque.

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 shift control system for an automatic transmission wherein shifting from a first gear ratio to a second gear ratio is carried out by releasing the hydraulic pressure of a first friction engaging element for disengagement thereof and supplying the hydraulic pressure to a second friction engaging element for engagement thereof, the hydraulic pressure to the second friction engaging element being subjected to feedback control, wherein the shift control system includes a sensor for sensing a parameter on a vehicle cruising condition; and an ECU having a part for calculating, in accordance with the sensed parameter, a difference in output-side rotational speed of the fluid coupling before and after the shifting; and a part for setting, when the shifting is carried out with an output of the engine being smaller than a predetermined value, the second hydraulic pressure in accordance with the calculated difference immediately before start of the feedback control.

Abstract: In a shift control system of an automatic transmission for a vehicle, an engaging torque applied to a predetermined friction element that has been engaged to establish a predetermined gear stage of the automatic transmission during running of the vehicle is gradually decreased to generate a slip in the predetermined friction element. Based on the engagigng torque of the friction element and a command value output to generate the engaging torque to the friction element, a predetermined relationship used for determining the command value for generating a required engaging torque is corrected. Learning quality or accuracy with respect to the predetermined relationship between the engaging torque of the friction element and the control value for generating the engaging torque may be sufficiently ensured.

Abstract: A transmission control method improves shift feel during kickdown shifts. The release clutch is fully released at the initiation of the kickdown shift. The release clutch is then reapplied when the volume of the release clutch reaches a threshold capacity. The volume of the release clutch is slowly ramped down, thereby increasing turbine speed. When the turbine speed reaches a threshold, the apply clutch is actuated. The apply clutch is actuated by controlling the volume of the apply clutch according to a target volume.

Abstract: A control system of a continuously variable transmission for a vehicle compensates for delays in an estimated input torque TINE based on a gradient value (variation) of the estimated input torque TINE,. For example, a friction force being applied to a driving belt of a continuously variable transmission is regulated according to the compensated estimated input torque TINE. Accordingly, an appropriate torque transmitting capacity is maintained in the transmission even at a rapid accelerating operation of the vehicle, while realizing good fuel efficiency.

Abstract: In an automatic transmission having a torque converter with a pump impeller, a turbine runner, and a stator, a stator shaft is provided to support the stator on its outer periphery and to rotatably support a transmission input shaft on its inner periphery. A magnetostrictive torque sensor is provided to detect the magnitude of input torque transmitted to the transmission input shaft. The magnetostrictive torque sensor includes a magnetic material having a magnetostrictive property and attached onto the outer periphery of the transmission input shaft, and a cylindrical magnetic-property detector mounted on the inner periphery of the stator shaft and arranged to be opposite to the magnetic material to detect a change in a magnetic property of the magnetic material, occurring owing to the input torque applied to the transmission input shaft.

Abstract: An automatic transmission achieves a desired shift through an initial stage shift in which a first engagement element is released and a third engagement element is engaged, and a final stage shift in which a second engagement element is released and a fourth engagement element is engaged. A control apparatus sets an estimated rotation acceleration for a transmission input shaft in accordance with an input torque and an input torque rotation acceleration speed, and controls the release of the second engagement element for moving to the final stage shift according to the estimated rotation acceleration. As a result, it is possible to prevent a shifting delay and/or degradation that occurs between the initial stage and the latter stage by continuous transmission of the input rotation (engine rotation) change when moving from the initial stage to the later stage.

Abstract: An automatic transmission achieves a desired shift through an initial stage shift in which a first engagement element is released and a third engagement element is engaged, and a final stage shift in which a second engagement element is released and a fourth engagement element is engaged. A control apparatus sets an estimated rotation acceleration for a transmission input shaft in accordance with an input torque and an input torque rotation acceleration speed, and controls the release of the second engagement element for moving to the final stage shift according to the estimated rotation acceleration. As a result, it is possible to prevent a shifting delay and/or degradation that occurs between the initial stage and the latter stage by continuous transmission of the input rotation (engine rotation) change when moving from the initial stage to the later stage.

Abstract: Siloxane compositions are useful as traction fluids in traction drive systems which are subject to varied operating temperature and pressure conditions. Specific siloxane compositions included contain units of formulae (I) (R3SiO1/2)(RSiO3/2)(SiO4/2), (II) (R3SiO1/2)(RSiO3/2), (III) (R3SiO1/2)(SiO4/2), (IV) (R3SiO1/2)(R2SiO2/2)(RSiO3/2), (V) (R3SiO1/2)(R2SiO2/2), and (VI) (R2SiO2/2)a in varying mole percents, where a is an integer ranging from 3 to 20 and each R is independently selected from alkyl groups comprising 1 to 18 carbon atoms and aryl groups comprising 6 to 18 carbon atoms.

Abstract: A control current is converted into an activation pressure for a transmission actuator by a pressure regulating valve. Both a control current at a given time and the activation pressure at the given time are fed back to a regulator. A setpoint value for the activation pressure in a partial range of a torque to be transmitted is converted by the regulator into the control current in dependence on the control current at the given time and otherwise as a function of the activation pressure at a given time. The current measuring device for determining the control current at the given time is adjusted here in such a way that a high resolution is obtained in the partial range.

Abstract: A torque calculator and method for providing real time data that measures net torque output of a running engine in a motor vehicle. Gross torque production is calculated using engine speed and fueling data. Torque losses due to accessories, pumping, and friction are calculated and subtracted from gross torque production, and inertial torque is also accounted for to yield engine net running torque. The engine net running torque data and engine speed data are processed according to a filter algorithm that compensates the engine net running torque data for engine speed. Transmission shifting is controlled by the speed-compensated engine net running torque.

Abstract: In a constitution that a transmission torque capacities of friction engagement elements are determined based on an input shaft torque of a speed change mechanism and a torque sharing ratio, a change velocity of the torque sharing ratio of when the transmission torque capacity of a release side friction engagement element is changed from a value greater than a critical transmission torque capacity to a value smaller than the critical transmission torque capacity, is abruptly altered when the input shaft torque is equal to or less than predetermined value.

Abstract: A control device for an automatic transmission which prevents an automatic transmission from executing a “busy-shift” caused by a lower gear ratio of the highest gear, and which reduces revolutions of a driving power source at high speed. The control device includes an automatic shift mode, an independent manual shift mode, and a highest gear control means. The automatic shift mode automatically determines a gear ratio of the automatic transmission on the basis of a driving condition of a vehicle having the automatic transmission. The manual shift mode determines a gear ratio of the automatic transmission by a driver's intention. The highest gear control means controls the automatic transmission, so that the smallest gear ratio set by the manual shift mode is smaller than the smallest gear ratio set by the automatic shift mode. If the gear ratio of the highest gear of the automatic shift mode is not so small, a shift caused by a change of a driving condition does not easily occur.

Abstract: A hydraulic control device for an automatic transmission capable of preventing engine racing and tie-up by controlling disengagement side oil pressure in accordance with an input torque and an oil temperature. Gear-change execution controller U4 controls drain timings T1 and T3 and a drain gradient &dgr;P of the disengagement side oil pressure acting on the frictional engagement elements of the disengagement side according to the magnitude of the input torque and elevation of the oil temperature in torque phase control wherein both the engagement side oil pressure and the disengagement side oil pressure are controlled.

Abstract: In an automatic transmission for conducting a gear change by replacing friction engagement elements, a transmission torque capacity of an engage side friction engagement element at a torque phase is corrected based upon a change amount per unit time of a turbine rotation speed at the torque phase or a torque phase time.

Abstract: An automatic transmission has a low clutch that assumes its engaged condition at a plurality of lower gear positions of D-range and a high clutch that assumes its engaged condition at a plurality of higher gear positions of D-range, A hydraulic control system for the transmission comprises a hydraulic section that produces a line pressure; a solenoid valve that produces a solenoid pressure upon receiving a solenoid signal; a first pressure control valve that produces a first output pressure from the line pressure by using the solenoid pressure and the first output pressure as operation signal pressures, the first output pressure having a smaller gain with respect to the solenoid pressure; a second pressure control valve that produces a second output pressure from the line pressure by using the solenoid pressure and the second output pressure as operation signal pressures, the second output pressure having a larger gain with respect to the solenoid pressure; and a switching valve that selectively assumes a fir

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: A control apparatus executes appropriate speed change control under any operating conditions encountered during an up-shift by change-over, without requiring an increase in control logic. Engagement side hydraulic pressure is swept up as a result of an arithmetic operation in torque phase speed change control. Disengagement side hydraulic pressure is calculated by initial speed change control, dependent on the engagement side hydraulic pressure. The engagement side hydraulic pressure is directly controlled and the disengagement side hydraulic pressure is indirectly controlled, i.e. responsive to the engagement side control. Consequently, the same control scheme can be executed regardless of power-on state or power-off state and regardless of vehicle operating conditions.

Abstract: A shift control apparatus for an automatic transmission includes a first transmission gear unit equipped with a clutch to clutch shift mechanism and a second transmission gear unit which is operatively connected in series with the first transmission gear unit and which is equipped with a clutch to one-way clutch shift mechanism. A clutch controller controls the clutch-to-clutch shift mechanism and the clutch to one-way clutch shift mechanism in such a manner that rotational synchronization of the clutch to one-way clutch shift mechanism is caused to take place earlier than or at the same time as rotational synchronization of the clutch to clutch shift mechanism when gear shifting is effected over the first and second transmission gear units.

Abstract: In a power train control apparatus including an engine, an automatic transmission having a torque converter, and a control unit for controlling the engine and the automatic transmission, the control apparatus is provided with a microcomputer for calculating and estimating values of the input shaft torque and a gear ratio of the automatic transmission. Various characteristics of the engine and the torque converter are obtained in advance by experiments, such as the relationship between an engine torque and an engine speed, and that between a pump capacity coefficient data and a slip ratio of the torque converter. Thereafter, data tables are made by using these characteristics, and control factors required to control the engine and the automatic transmission are made as an equation in relation to the input shaft torque and the gear ratio so as that they can be calculated by the microcomputer.

Abstract: A control system for an automatic transmission in a vehicle powertrain including an engine and a fluid coupling for transmitting the rotation of an engine to the transmission, the transmission having a clutch which is applied responsive to selection of a forward running range and a hydraulic servo for applying the clutch responsive to an oil pressure. The control system includes a control unit for controlling the oil pressure to the hydraulic servo; an input torque detector for detecting the input torque to be inputted to the transmission; and a specific state detector for detecting satisfaction of a set of specific starting conditions including: (1) that the forward running range has been selected, (2) that the vehicle is stopped and (3) that the engine is in an idling state.

Abstract: A frictional engagement device for an automatic transmission, by which an input shaft and an output shaft are engaged or disengaged by use of oil pressure. A casing connected to an input shaft and a first piston disposed in the casing define a first oil pressure chamber. The first piston is rotationally movable by predetermined angle and is axially movable by predetermined distance relative to the casing. A second piston disposed in the first piston defines a second oil pressure chamber with the first piston, and the second piston is axially movable relative to the first piston. Separator plates axially slidably connected to the first piston and clutch discs axially slidably connected to a hub which is fixedly connected to the output shaft are engaged by a displacement of the second piston by supplying pressurized oil to the second oil pressure chamber and/or to the first oil pressure chamber.

Abstract: A controller of an automatic transmission provides gear changes with optimum gear change characteristics under any traveling conditions. The controller of the automatic transmission of the present invention includes an input torque detector for determining input torque to the transmission, an inertia torque estimator for estimating an inertia torque corresponding to the rate of change of rotary speed of a rotary member during a gear change, input torque corrector for calculating a required operating torque by adding the input torque and the inertia torque and an operating pressure controller for controlling operating pressure to correspond to the required operating torque. The operating pressure corresponding to the necessary engagement torque is supplied to a hydraulic servo, to effect a gear change, irrespective throttle opening and driving speed and irrespective of whether the gear change is made step by step or jumped.

Abstract: The invention is directed to a method for adjusting the hydraulic pressure actuating at least one clutch of an automatic transmission. The hydraulic pressure is pregiven only by one pressure controller and the automatic transmission coacts with the motor which is especially a drive motor of a motor vehicle. The pressure supplied by the pressure controller is determined in dependence upon the trace of a pregiven motor desired torque.