Abstract: A vehicle having an automatic transmission includes a roll-back detector that generates a roll-back signal indicating a vehicle roll-back event. A controller receives the roll-back signal and determines whether the automatic transmission is in a forward drive mode having first and second torque transfer elements engaged. The controller engages a third torque transfer element to prevent the vehicle roll-back event.

Abstract: A hydraulic circuit for a continuously variable transmission having a continuously variable ratio unit that is controlled by at least one hydraulic actuator acting on a movable torque transmission element. The actuator has opposed first and second working chambers. The circuit includes first and second flow lines that are connected to two respective actuator working chambers. The lines feed fluid thereto and therefrom A pressurized supply of fluid urges fluid flow through the flow lines. A variable control valve is incorporated in both flow lines. Each valve generates an adjustable back pressure therein. A further valve is connected between the two flow lines. The further valve has a variable opening and is located upstream of the variable control valve. Opening of the further valve enables flow fluid from one flow line to the other to reduce pressure difference between the lines.

Abstract: A shift hydraulic apparatus and method are provided for a vehicular automatic transmission constituted by a torque converter and a continuously variable transmission. A bypass circuit enables an upstream side hydraulic circuit of the hydraulic circuit to communicate with a downstream side hydraulic circuit. A switching valve enables a switching between a communication state of the bypass circuit and a non-communication state thereof. Through the switching valve, both communication state and the non-communication state of the bypass circuit are controlled.

Abstract: There is provided a control system for a vehicle, which is capable of increasing the service life of a transmission belt while preventing slippage thereof, and at the same time improving fuel economy and drivability. The control system for a vehicle sets a transmission transfer torque to be transmitted from a drive pulley of a continuously variable transmission to a driven pulley of the same, and a clutch transfer torque to be transferred by a clutch. When it is determined that the vehicle is traveling on a bad road, the clutch transfer torque is reduced, and the transmission transfer torque is set to a larger value as the clutch transfer torque is larger.

Abstract: In a hydraulic system for an automatic transmission, a method for automatically draining fluid from an oil cooler and related hydraulic lines when power is off to prevent fluid leakage, escape and outflow when they are disconnected from the system. A control system includes a source of relatively high pressure when power is on, an oil cooler, fluid circuit lines for supplying transmission oil to the cooler, a source of low pressure for containing fluid, such as an oil sump, and a valve hydraulically connected to the circuit, high pressure source, and low pressure source, the valve having a first state at which a hydraulic connection through the valve between the circuit and the source of low pressure is closed when power is on, and a second state at which a hydraulic connection through the valve between the circuit and the low pressure source is open when power is off.

Abstract: In a toroidal continuously variable transmission (TCVT) control apparatus with a variator unit and a ratio control hydraulic system, an electronic TCVT control unit electronically feedback-controls a transmission ratio based on a deviation from a desired transmission ratio, and generates a normal-period command signal to be input to a step motor for compensating for the deviation. The control unit determines whether the deviation can be compensated for by electronically feedback-controlling the transmission ratio based on the deviation and generates an abnormal-period command signal to be input to the step motor to realize a step-motor displacement capable of shifting or diverging the transmission ratio to a speed-reduction side, while keeping a trunnion out of contact with a stopper in the direction of the trunnion axis, when the deviation cannot be compensated for by electronically feedback-controlling the transmission ratio based on the deviation.

Abstract: A control apparatus for controlling transmission ratio of a toroidal-type continuously variable transmission unit of a continuously variable transmission apparatus, the continuously variable transmission apparatus has: a toroidal-type continuously variable transmission unit, which changes a transmission ratio between pair of disks by shifting trunnions in the axial direction of pivot shafts by using actuators; and, a differential unit of a gear type including a combination of a plurality of gears, the control apparatus having: rotation speed control unit; transmission ratio setting unit; oil pressure measuring unit; and, transmission ratio correcting unit operating in response to a deviation of a pressure difference between a measured value by the oil pressure measuring unit and a target value of a torque passing through the toroidal-type continuously variable transmission unit, and adjusting the transmission ratio of the toroidal-type continuously variable transmission unit so as to eliminate the deviation.

Abstract: A method and apparatus for operating an automatic transmission as a function of the engine rotational speed of a variable speed internal combustion engine. Upon a failure of the electronic control system, a return home of a motor vehicle under its own power is enabled. A delivery system delivers a working medium with which a transmission ratio adjusting device is actuated by a first control device that, in turn, is controlled by a pilot pressure that can be accurately changed by a second control device to actuate the transmission ratio adjusting device. The pilot pressure for controlling the first control device is changed by a third control device as a function of the rotational speed of the internal combustion engine when an adjusting device is switched out of a normal operation position into an emergency operation position.

Abstract: An automatic transmission comprises a metal V-belt mechanism 10, which changes the speed ratio of the rotational output from an engine ENG, a forward/reverse direction change mechanism 20, which switches the rotational direction of the ratio-change mechanism, and a forward clutch 30, which actuates the switching operation of the rotational direction performed by the forward/reverse direction-change mechanism. A control system for this transmission comprises a regulator valve 50, which generates a line pressure, a manual valve 80, which is operated in correspondence to the shift lever and switches the supply of the line pressure to the forward clutch, and a drive-range sensor 105, which detects the operation of the manual valve. When the movement of the manual valve to a position where the line pressure is to be supplied to the forward clutch is detected by the drive-range sensor 105, the line pressure, which is adjusted by the regulator valve, is lowered for a predetermined time period.

Abstract: In a slippage prevention apparatus of a belt-drive continuously variable transmission for an automotive vehicle in which a transmission ratio is controlled by a speed-change hydraulic pressure brought closer to a desired speed-change hydraulic pressure, a quick-acceleration-frequency decision section is provided to determine whether a frequency of quick accelerating operations is low or high. Also provided is a desired hydraulic pressure decision section that sets the desired speed-change hydraulic pressure used during an operating mode that the frequency of quick accelerating operations is low to a relatively lower pressure level than the desired speed-change hydraulic pressure used during an operating mode that the frequency of quick accelerating operations is high.

Abstract: An automatic transmission control apparatus includes a continuously variable transmission (CVT) which, in turn, includes a primary pulley, a secondary pulley, a belt stretched between the primary pulley and the secondary pulley. The control apparatus further includes a pinching pressure generator for generating a pinching pressure on the belt, a travel environment all detector for detecting the travel environment of a vehicle, a torque variation estimator for estimating the transmission torque variation during travel, and a pinching pressure changer for changing the pinching pressure based on the estimation. The pinching pressure is prevented from constantly increasing because the transmission torque variation during travel is estimated, and the pinching pressure for the belt is changed based on the estimation. Accordingly, the torque transmission efficiency can be increased, and the fuel efficiency can thus be improved.

Abstract: A device for hydraulically controlling a continuously variable transmission by decreasing the load exerted on an engine to improve the fuel efficiency and preventing the slipping. The device includes a belt slip detector unit 27 which forms a slip detection signal DS when a slipping state of a V-belt is detected, and a belt slip suppressing unit 25, 26, SW1 which executes a correction processing for suppressing the slipping in response to the slip detection signal. The line pressure is set to a minimum required value until the slip is detected, and the correction processing is executed for suppressing the slip only when the slip is detected.

Abstract: The trunnion (23) of a vehicle toroidal continuously variable transmission is displaced by a step motor (52) via a control valve (56) and oil pressure servo cylinder (50) in order to vary a speed ratio of the transmission. A controller (80) calculates a target value (z*) of a control variable (z) based on an accelerator pedal depression amount (APS) and output disk rotation speed (&ohgr;co) (S5). Further, a time-variant coefficient (f) showing the relation between the trunnion displacement (y) and variation rate ({dot over (&phgr;)}) of the gyration angle (&phgr;) of the power roller, is calculated (S10). The error between the speed change response of the transmission and a target linear characteristic can be decreased by determining a command value (u) to the step motor (52) under a control gain determined based on a time differential ({dot over (f)}) of the coefficient (f) (S20).

Abstract: A modular electronic control system for a geared multiple-ratio transmission wherein pressure profiles for each ratio shift actuator are used to provide seamless transitions during both positive and negative engine torque conditions to improve shift feel and responsiveness to ratio change commands. The system provides shift staging for sequenced shifts between ratios as well as for so-called “change-of-mind” shifts in which a sequence shift is interrupted as a new destination gear is introduced. A constant ratio change occurs during sequenced shifts. A change-of-mind shift can be performed directly where the new destination gear is commanded immediately. Independent pressure profiles for each clutch involved in a commanded shift are used to accommodate various types of shifts.

Abstract: Within the scope of the method for regulating the rotational speed difference of a switchable frictional engagement control, specially of a clutch or brake, in the driving train of a motor vehicle by means of a control closed loop with the desired rotational speed difference as reference input and the actual rotational speed difference as controlled variable, together with the clutch pressure or brake pressure to be adjusted, at least one other controlled variable is used, wherein the closed loop comprises a linear governor and damping members (TP1, TP2, TP3) in a manner such that the time shift of the damped variable per reading step does not exceed a predetermined value so that the exciting of the closed loop remains within a stable range for controlling.

Abstract: The invention proceeds from a system for generating a signal for hydraulically adjusting the transmission ratio of a continuously variable transmission in a motor vehicle. Here, a valve is provided which influences the hydraulic connection from a pressure reservoir, which exhibits a hydraulic pressure, to a pressure chamber. The adjustment of the transmission ratio takes place via the drive of at least the valve via the electrical signal. For this purpose, the electrical signal is generated in such a manner that it is limited to maximum and/or minimum values. The essence of the invention is that the maximum and/or minimum values are determined in dependence upon the hydraulic pressure. With the limiting in accordance with the invention, it is ensured that an adequate pressure reserve for the adjustment of the belt tension is available notwithstanding the adjustment of the transmission ratio.

Abstract: A shift control system of a hydraulic CVT for an automotive vehicle with which it is possible to control a speed ratio to a target value with certainty while maintaining a required primary pressure, even when the vehicle is substantially stationary. Normally, a speed feedback control means sets a target speed of a rotating element on the basis of the vehicle speed and the load on the vehicle engine. The speed feedback control means feedback-controls a hydraulic pressure control means of the rotating element so that the actual speed approaches the target speed. When the vehicle becomes substantially stationary, control of the hydraulic pressure control means is switched from the speed feedback control executed by the speed feedback control means to pressure feedback control executed by a pressure feedback control means. That is, the actual hydraulic pressure acting on the rotating element is detected by a hydraulic pressure detecting means.

Abstract: When an ignition switch is turned off to stop an engine, a control apparatus of a continuously variable transmission places a line pressure regulating valve in a fully draining condition to reduce a load of a hydraulic pump by maintaining an electric power supply to the line pressure regulating valve, a shift control pressure regulating valve and the control apparatus.

Abstract: Leak oil from a regulator 24 for regulating the pressure of oil supplied to a lubricating system (the lubricating pressure) is supplied to an oil cooler 23. An electromagnetic valve 25 is connected to a pressure controlling and regulating oil chamber 24a of the regulator 24 so that the lubricating pressure can be controlled to be increased or decreased. The lubricating pressure is decreased while an engine is running in a low load state during a high-speed running to thereby increase the volume of oil to be supplied to the oil cooler 23.

Abstract: A hydraulic control system including: a rotating speed raising unit for raising the rotating speed of the prime mover while the transmission is not rotated by the prime mover, to increase an output volume of the hydraulic pump; at oil pressure instructor for outputting a plurality of instruction signals of different pressure instruction values to the valve modulating mechanism while the output volume of the hydraulic pump is increased; an oil pressure detector for detecting the oil pressure to be modulated and fed to the transmission, at a plurality of pressure levels; and a learning corrector for learning and correcting the instruction signals on the basis of the outputted pressure instruction value and the detected oil pressure detected.

Abstract: In a control apparatus for an automotive continuously variable transmission having a forward-reverse selector mechanism in which a gear ratio for reverse is set closer to a speed reducing side than a gear ratio for forward and a belt type continuously variable transmission mechanism, a PH pressure that is outputted from a first regulator valve and a PL pressure that is outputted from a second regulator valve are changeably supplied to one and the other of a hydraulic cylinder of a drive pulley and a hydraulic cylinder of a driven pulley via a shift control valve. A hydraulic pressure supplied to a reversing hydraulic pressure connecting element from a reversing manual valve is inputted into an oil chamber of a first regulator valve so that the PH pressure is increased with the hydraulic pressure so inputted.

Abstract: A method and apparatus for operating an automatic transmission as a function of the engine rotational speed of a variable speed internal combustion engine. Upon a failure of the electronic control system, a return home of a motor vehicle under its own power is enabled. A delivery system delivers a working medium with which a transmission ratio adjusting device is actuated by a first control device that, in turn, is controlled by a pilot pressure that can be accurately changed by a second control device to actuate the transmission ratio adjusting device. The pilot pressure for controlling the first control device is changed by a third control device as a function of the rotational speed of the internal combustion engine when an adjusting device is switched out of a normal operation position into an emergency operation position.

Abstract: A line pressure control device for a continuously variable transmission comprises: a target line pressure setting part that sets a target value of a line pressure, which is able to adjust a clamping force applied to a transmission member of the continuously variable transmission; and an engine torque suppressing part that suppresses an engine torque to prevent the transmission member from slipping. When it is impossible to suppress the engine torque and thus a torque non-suppressible flag is set, the target value of the line pressure is corrected to a greater value to prevent the transmission member from slipping. Otherwise, the target value of the line pressure is set to a smaller value. This makes it possible to surely prevent the transmission member from slipping.

Abstract: A transmission comprises: an input shaft intended to be coupled to a motor; an output shaft; an epicyclic reduction unit with an input sun wheel, a ring gear and first and second output shafts respectively fast and slow; a first clutch for connecting the input sun wheel to the ring gear of the said reduction unit; an hydraulic variator unit coupled between the input shaft of the transmission and the input sun wheel; second and third clutches operable to connect the input shaft of the transmission with the ring gear of the epicyclic reduction gear unit to give respective transmission ratios of opposite sign, respectively for forward and reverse gears. The arrangement is such that when the output speed of the variator varies over a predetermined range on either side of zero, and the first clutch is disengaged and the second or third clutch is engaged, the first and the second output shaft of the epicyclic reduction unit have respective speeds which vary over respective ranges of contiguous values.

Abstract: In an infinite speed ratio transmission, a rotation of an input shaft (1) is input both to a continuously variable transmission (2) and a fixed speed ratio transmission (3). A CVT output shaft (4) of the toroidal continuously variable transmission (2) is joined to a sun gear (5A) of a planetary gear set (5), an output shaft (3C) of the fixed speed ratio transmission (3) is joined to a planet carrier (5B) of the planetary gear set (5), and a vehicle is driven under the output of a ring gear (5C) of the planetary gear set (5). A controller of the infinite speed ratio transmission comprises an actuator (30) which varies an amount of torque transmitted between the input shaft (1) and the CVT output shaft (4). A microprocessor (80) controls the actuator (30) so that a torque in the opposite direction to the vehicle travel direction shown by a selection range of a selector lever (86) is not transmitted by the continuously variable transmission (2).

Abstract: A transmission has an rpm-converter controlled by a hydraulic system. The hydraulic system has a supply circuit from a fluid-conveyor device to the rpm-converter, a return circuit to carry the spent fluid back from the rpm-converter, and a run-off circuit to return the run-off portion of fluid from a flow-regulating device that regulates the volume flow in the supply circuit. The return circuit and the run-off circuit are merged in a circuit junction that continues into a flow-back circuit.

Abstract: In an apparatus for controlling a pulley side-pressure of a belt type continuously variable transmission mechanism provided, in series with a starting clutch, in a transmission of a vehicle having a function of stopping engine idling so that an engine is automatically stopped, if the vehicle start-up is controlled from the state of engine stopping in an ordinary way in which the pulley side-pressure is determined by that belt transmission torque corresponding to an output torque of the engine which is obtained by the rotational speed and the negative suction pressure of the engine, the pulley side-pressure becomes excessive by wrong judgement that the engine output torque is large, because the negative suction pressure is small at the beginning of the engine starting. The durability then deteriorates and the specific fuel consumption becomes poor.

Abstract: A clutch (25, 26) which connects an engine to a toroidal continuously variable transmission (100) is engaged and transmits a torque to the transmission (100) according to a line pressure. The toroidal continuously variable transmission (100) transmits the torque also according to the line pressure. A microprocessor (81) calculates a first pressure required to engage the clutch (25, 26) in the idle running state of the engine (99), calculates a second pressure required for torque transmission of the clutch (25, 26) based on a torque transmission amount of the clutch (25, 26) (S141), and calculates a third pressure required for torque transmission of the continuously variable transmission (100) based on the torque transmission amount of the clutch (25, 26) and the speed ratio of the continuously variable transmission (100) (S142).

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: A motor vehicle has a continuously variable transmission and a hydraulic device to perform the functions of changing as well as maintaining the ratio of the continuously variable transmission. The hydraulic device comprises a valve arrangement with at least one connector terminal for controlling a transmission ratio change and at least one connector terminal for maintaining the transmission ratio at a set level.

Abstract: A method for control of a positioning and/or angle control device without an absolute position sensor and the device itself is proposed as having at least one position label for a controllable part in a motor vehicle using an electronic circuit. The positioning and/or angle control device initialized after termination of the operation of the motor vehicle.

Abstract: A select-shock control system of an automotive automatic transmission is shown. The transmission has an engaging element which becomes engaged due to application of hydraulic pressure thereto when it is needed to shift the transmission from a neutral condition to a drive condition.

Abstract: A controller (61) for a line pressure control device of a transmission (200) determines whether or not a vehicle speed is above a fixed vehicle speed. The controller (61) set a target line pressure in response to a torque input into said transmission (200) when the vehicle speed is lower than the fixed vehicle speed. When the vehicle speed is higher than the fixed vehicle speed, the target line pressure is increased to a fixed hugh line pressure irrespective of the torque input into the transmission (200). In this way, it is possible to prevent deficiencies in an amount of lubricant when the vehicle is running at a high speed.

Abstract: A process is proposed for automatically coordinating the filling and feeding operation of hydraulically operated and hydraulically or electronically individually commanded shift elements. The filling and feeding operation is divided into a rapid filling phase and a filling equalization phase and has as parameters at least one rapid filling period, one rapid filling pressure, one filling equalization period and one filling equalization pressure. To optimize said parameters two of the four are preset and for the other two, an optimal value is determined for the first parameter to be optimized on the basis of a preset, time-dependent pressure curve in which a pressure increase phase follows the rapid filling phase and equalization phase. To this end, based on an initial value presettable in each case, the first parameter is gradually adjusted until a speed change occurs at or before the start of the pressure increase phase.

Abstract: In an engine provided with a throttle valve actuator which controls the opening/closing of the throttle valve, a target throttle valve opening degree is determined based the amount of accelerator pedal depression. Following a speed change command being issued in an automatic transmission the target throttle position is gradually decreased until an inertial phase is detected. The target throttle opening is then returned to that which corresponds to the accelerator pedal depression by the driver.

Abstract: A control for determining the state of adjustment or misadjustment of a master friction clutch (14) in a vehicular automated mechanical transmission system (10). A system controller (24) receives input signals (26) indicative of the engaged or disengaged condition of the master clutch, the rotational speed of the transmission input shaft (IS) and the engaged or disengaged condition of the mechanical transmission (16). When the master clutch and the transmission both are disengaged, the rate of change of input shaft speed (dIS/dt) is compared to a predetermined reference value, and if the rate of deceleration of the input shaft speed is less than said reference value, significant master clutch misadjustment is determined and corrective action is initiated. Corrective action may include causing a display (48) to signal the operator that the master clutch is improperly adjusted and/or operating an input shaft brake (50) in a fault-tolerant mode.

Abstract: A speed ratio of a continuously variable transmission is varied according to an oil pressure which is adjusted by a valve driven by a step motor. The step motor is feedback controlled so that a real speed ratio coincides with a target speed ratio determined according to the running conditions of a vehicle. By determining a feedback gain based on the oil pressure, oil temperature, real speed ratio and output shaft rotation speed of the transmission, precise control of the speed ratio according to the running state is realized.

Abstract: In a continuously variable transmission which varies a speed change ratio based on a target speed change ratio which has been set according to a running condition of a vehicle, a sensor is provided for detecting the temperature of the continuously variable transmission. A shift amount of the speed change ratio due to a thermal expansion difference of parts of the continuously variable transmission is prevented by correcting the target speed change ratio based on the temperature detected by the sensor.

Abstract: A toroidal type continuously variable transmission whose gear ratio is varied by changing the position of a trunnion is provided with double-slider valves driven by stepping motors and linear solenoid valves. The gear ratio control is performed by controlling position of the double-slider valves when the vehicle travels at speeds higher than a specified speed or by controlling directly line and relief pressures applied to the trunnion through the solenoid valves.

Abstract: Two speed change units of a continuously variable transmission for a vehicle are accommodated in chambers partitioned by an intermediate wall in a casing. Oil pan is fitted to the underside of the casing in order to store lubricating oil for the units. A strainer for filtering the lubricating oil is disposed in the oil pan. A controller comprising a control valve driven by an actuator via a speed change link, a cam and a feedback link is provided for controlling the speed change ratio of the speed change units. The actuator is disposed further towards the rear of the vehicle body than the intermediate wall. The control valve, feedback link and cam are disposed further towards the front of the vehicle body than the intermediate wall. This arrangement avoids the interference of the actuator and the strainer.

Abstract: The electro-hydraulic control device is designed to control a continuously variable loop transmission including a hydraulic bevel disk displacement device having two pairs of bevel disks, each pair of which has piston/cylinder elements with a piston chamber, and a pump for supplying one of the piston chambers with hydraulic oil. The electro-hydraulic control device supplies and regulates a hydraulic pressure in the piston chamber by means of a flow control valve (50) and a proportioning pressure relief valve (30). The electro-hydraulic control device also includes a pressure sensor (90) for generating an electronic pressure sensor signal according to the hydraulic pressure in a low-pressure control pressure line (34) connecting the flow control valve (50) and the proportioning pressure relief valve (30) and an electronic control unit for generating an electrical current for actuating the flow control valve (50) according to the pressure sensor signal.

Abstract: An automatic transmission having a multiple ratio gearset arranged in series with an overdrive gearset wherein ratio upshifts and downshifts are effected by separate reaction brakes for each gearset, each brake being independently controlled to achieve an enhancement of shift quality using closed loop control of reaction brake pressure and high ratio clutch pressure as a function of turbine speed, output shaft speed, brake drum speed for the multiple ratio gearset and input shaft speed in establishing control of upshifts and downshifts.

Abstract: This toroidal continuous variable transmission detects a deviation of the spool valve from its neutral position and performs a feedback control to prevent the transmission ratio from converging on other than the target transmission ratio or the speed change sequence from being started again. Further, the toroidal continuous variable transmission performs control so that as the actual transmission ratio approaches the target transmission ratio, the transmission speed decreases in order to prevent an overshoot of the speed change control. When the difference between the actual transmission ratio and the target transmission ratio is smaller than a specified value, the output signals to the solenoid valves are controlled so that the pressure difference between the pilot pressures acting on the ends of the spool valves is proportional to the difference between the actual transmission ratio and the target transmission ratio.

Abstract: When a failure occurs with the electrical system while the car is traveling at low speed, the toroidal continuous variable transmission fixes the transmission ratio to a value on the speed-decrease side, so that the car can start even when the car stops on a slope or it is heavily loaded. Further, when one spool valve is at the neutral position and if one of the trunnions supporting the power rollers should receive a force due to torque variations in the input disk, the other trunnion is not affected at all and not displaced.

Abstract: A shift control system for a troidal continuously variable transmission comprises an electronic system for calculating a shift command value, a first electronic feedback system for feeding back a first physical quantity indicative of the tilting angle of power rollers, and a second electronic feedback system for feeding back a second physical quantity indicative of a speed of change of the tilting angle of the power rollers, the electronic system calculating the shift command value in accordance with the first and second physical quantities.

Abstract: The present invention provides a toroidal continuous variable transmission, which corrects an output signal to the solenoid valve according to changes in the temperature of the working oil and thereby secures a desired transmission ratio without being affected by working oil temperature changes or by variations in performance of the constitutional components. The controller has stored in memory a relation, predetermined from experiments, between the working oil temperature and the characteristic of output pressure supplied from the solenoid valve. Once the target transmission ratio is determined by the main routine, the controller calculates the amount of correction for the output signal to the solenoid valve based on the signal from the oil temperature sensor, corrects the conventional output signal by the correction amount, and outputs the corrected output signal to the solenoid valve.

Abstract: Power rollers in a toroidal continuous variable transmission receive an external force from input and output discs. The external force is supplied to trunnions, so that pressure in one cylinder chamber becomes higher than that in the other, and a sleeve is urged to be shifted away from a neutral position. However, return force urging the sleeve back to the neutral position occurs. Since this return urging force is equal in magnitude to the external force and works in the direction opposite to that of the external force, the external force is offset by the urging force, and the trunnions are not displaced. Or, a controller outputs a control signal, corresponding to a difference between a target variable speed ratio and an actual variable speed ratio, to solenoid valves so as to generate in the cylinder chambers a pressure difference for offsetting the external force F. Accordingly the trunnions are maintained in the neutral positions, and a speed changing operation is not started again.

Abstract: A vehicle driveline including a control system subject to operator demand, and a continuously-variable-ratio transmission including a variator of the torque-controlled type in which the control system includes a performance "map" of optimum relationships between engine torque and speed over a range of values of those two quantities, and in which the control system regulates both the energy input to an engine and also the reaction torque at the variator so as to seek a state in which the mapped optimum relationship between engine torque and speed is maintained. The variator may be of the toroidal-race rolling-traction type, reaction torque within it being regulated by controlling the operating force applied to the variator rollers.

Abstract: A hydraulic control system for shifting a positive variable drive transmission includes a series of indexing mechanisms 90 through 95 for indexing a series of overrunning clutches between to two limit positions. A selector valve 150 controlled by a computer 162 directs flows of pressurized fluid to the indexing mechanisms 90 through 95. A motor 152 indexes a shear plate 172 of the selector valve 150 to predetermined positions for shifting the transmission.