Abstract: In order to optimize the speed change control of a continuously variable transmission, a necessary minimum primary pressure (Ppmin) for achieving speed change ratio control, a necessary minimum line pressure (Plmin) for the non occurrence of slippage between a secondary pulley 3 and a belt 4, and a required speed change ratio line pressure (Plratio) which can realize a target speed change ratio without slippage on the primary pulley 2 side are computed. The highest of these is then selected, and a final output line pressure (Plprs) then obtained based on the selected line pressure. By using this line pressure (Plprs) to control a secondary pulley actuator 3a, slipping of the belt 4 can be prevented and a target speed change ratio achieved, with an extremely simple construction compared to that of conventional arrangements.

Abstract: A method for controlling the transmission ratio (input speed/output speed) of a continuously variable transmission, in particular for a motor vehicle. The transmission can be set to a second operational state as a result of energization by an activation signal. In the second operational state, the transmission ratio increases or decreases in the event of a decrease of increase, respectively, in the output speed of the transmission. In the second operational state, the transmission ratio is controlled using a control line, which intersects a point determined by the instantaneous input speed and instantaneous output speed of the transmission at the instant of commencement of said second operational state and also intersects a starting point determined by an input speed equal to zero and an output speed notionally less than zero. The invention also relates to an apparatus for carrying out the method.

Abstract: A basic speed change ratio is set on the basis of vehicle speed and throttle valve opening, and a control target speed change ratio is made to gradually approach the basic speed change ratio in accordance with a speed change speed. Feedback control is then carried out so that the actual speed change ratio coincides with the control target speed change ratio. When there is an up-shift requirement with a rate of change in throttle valve opening equal to or less than a predetermined value, and a rate of change in the basic speed change ratio, which is set on the basis of operating conditions, equal to or less than a predetermined value, the speed change speed is faster than at the time of an up-shift requirement with throttle valve closure.

Abstract: A speed change controlling apparatus and method for a non-stage change-gear system of the V-belt type or CVT are disclosed, wherein control is performed based particularly on the torque of a non-stage change-gear to meet with a high degree of accuracy requirements in which importance is attached to the fuel cost of a vehicle or the power performance and the time for development of a speed change schedule is avoided. A torque of a change-gear is estimated and speed change control is performed based on a targeted drive shaft torque so that the necessity for a speed change schedule map is eliminated and accurate speed change control based on the torque is performed. Consequently, an object speed change characteristic can be produced readily with a high degree of accuracy. Because matching need not be performed for each vehicle, the development man-hours can be reduced remarkably.

Abstract: In a control apparatus for controlling a gear shift ratio of a continuously variable transmission mounted in an automotive vehicle as an automatic power transmission, a gear shift ratio command value is calculated using a control constant corresponding to a dynamic characteristic determined for each instantaneous gear shift ratio of the continuously variable transmission so as to achieve a target gear shift ratio response characteristic.

Abstract: With the present invention, it is possible for a vehicle to run on an uphill road at substantially the same throttle opening as on a horizontal road.When the road is uphill (hill-climbing resistance R.theta.>0), a maximum acceleration Amax for a full throttle opening is obtained according to a vehicle speed, and a maximum driving force Fmax=m.multidot.Amax+RL is calculated based on the mass of the vehicle m and the rolling and air resistance RL of the vehicle. Then, a correction coefficient HOS is obtained according to a throttle opening to calculale a required driving force Ftgt=Fmax.multidot.HOS. According to the required driving force Ftgt, hill-climbing resistance R.theta., and vehicle speed VSP, a target horsepower Ptgt=(Ftgt+R.theta.).multidot.VSP is calculated. To attain the target horsepower Ptgt, a target speed change ratio "itgt" for a continuously variable transmission is calculated to control the transmission.

Abstract: A control apparatus for a belt-type continuously variable transmission that has a drive pulley, a driven pulley, a V-belt trained around the drive and driven pulleys, a drive cylinder for varying the pulley width of the drive pulley, and a driven cylinder for varying the pulley width the said driven pulley. A pressure regulator valve produces pulley control pressures supplied to the drive and driven cylinders and a shift valve distributes the pulley control pressures to the drive and driven cylinders for varying the widths of the drive and driven pulleys for speed ratio control. An electric shift control normally controls the shift valve by electric power supplied to solenoid valves but the electric shift control causes the pressures in both the drive cylinder and said driven cylinder to be equal when the electric power is lost.

Abstract: The gear ratio of a belt-type continuously variable transmission is changed by increasing or decreasing the hydraulic pressure applied to an oil chamber for a drive pulley by a ratio control valve. A spool of the ratio control valve is driven by a normally opened solenoid valve and a normally closed solenoid valve. In a lower gear ratio range, the gear ratio is controlled by controlling the duty rate of the normally opened solenoid valve, and in a higher gear ratio range, the gear ratio is controlled by controlling the duty rate of the normally closed solenoid valve. When any trouble is generated, the gear ratio is held at an intermediate value by bringing both the duty rates of the normally opened solenoid valve and the normally closed solenoid valve into 0% or 100%. Thus, it is possible to finely control the gear ratio of the belt-type continuously variable transmission and, when any trouble is generated, the gear ratio can be held at the value intermediate between a LOW value and an OD value.

Abstract: A belt type continuously variable transmission (CVT) and a planetary gear unit are combined in a continuously variable transmission system for an automobile to deliver an output from the output shaft in the normal and reverse directions with a neutral position therebetween. A control mechanism with a hydraulic circuit controls hydraulic pressure of primary and secondary hydraulic servos for controlling axial forces applied to respective primary and secondary pulleys of the belt type continuously variable transmission. When an axial force difference is produced between the primary pulley and the secondary pulley, the belt type continuously variable transmission changes its speed corresponding to a torque transmission direction and normal and reverse rotation directions.

Abstract: The invention provides a method and apparatus for controlling a continuously variable speed transmission of a motor vehicle driven by an internal-combustion engine, by means of a control arrangement having a selecting device which simulates a stepped transmission by adjusting transmission ratios in according to a group of preset transmission ratios. To prevent repeated up and down shifting, a control arrangement is provided with a unit for detecting driving situations in which a transmission ratio shift according to the preset transmission rations would be too large, and also a unit for adjusting the preset transmission ratio. The recognition unit activates the adjustment unit as soon as the above-described driving situation occurs, and the adjustment unit then changes a preset transmission ratio so that the motive force is adapted to the present motive resistance, allowing the vehicle to achieve a positive longitudinal acceleration.

Abstract: A control system (in FIG. 1A) for a motor vehicle having a continuously variable transmission, in which a control of better fuel consumption is selected between the retardation angle correction (the correction of the retardation angle side of an advance angle correction) of the ignition timing of an internal combustion engine and the increase correction of the target r.p.m. of a continuously variable transmission, and the selected control is executed, whereby the fuel consumption of the engine is relieved from worsening in a control for the prevention of knocking or for the suppression of NOx in emission.

Abstract: A control system and process for an infinitely variable transmission which has a first operating mode which automatically selects the transmission ratio, and a second operating mode in which the transmission ratio can be selected directly by the driver. According to the invention, the degree of damping effective during the adjustment of the transmission ratio is adjusted in response to the selected operating mode. In the automatic operating mode, a high degree of damping is used, while in the manual operating mode, a lower degree of damping is provided.

Abstract: The speed change ratio of a continuously variable transmission is controlled so that the actual speed change ratio approaches the basic speed change ratio at a predetermined rate of changing the speed by setting the basic speed change ratio based upon the opening degree of the accelerator and the vehicle speed. Here, when a change in the basic speed change ratio accompanying the accelerator operation is against the direction in which the actual speed change ratio approaches the basic speed change ratio, the speed is forcibly and temporarily changed to follow the change in the basic speed change ratio.

Abstract: The invention improves the driveability of a vehicle by controlling a target engine speed according to an engine load and a vehicle running condition to ensure an actual engine speed. In controlling a speed ratio of a continuously variable transmission, an adaptation factor is used for deciding a target engine speed, the adaptation factor is determined according to constants, an average engine load and an average vehicle speed change quantity. Even when the average engine load changes because of fluctuation in an accelerator opening, various running modes can be decided by the adaptation factor depending upon both the average engine load and the average vehicle speed change quantity, thereby improving driveability upon changing speed of the continuously variable transmission.

Abstract: A control system for an engine-CVT drive-train includes a ratio control element positionable to various command positions in response to a rate of change per unit time of CVT ratio determined by a controller to establish various CVT ratios. The controller decreases the rate of change per unit time of CVT ratio as the rate of change per unit time of the position of a gas pedal toward a release position thereof increases.

Abstract: A pulley thrust pressure control apparatus for a belt-type continuously variable transmission having a drive pulley connected with an input member, a driven pulley connected with an output member, a V-belt trained around the drive and driven pulleys, a drive cylinder for varying the pulley width of the drive pulley, and a driven cylinder for varying the pulley width of the driven pulley. The actual transmitting torque transmitted through the V-belt is calculated and a belt transmittable torque is calculated by multiplying the actual transmitting torque by a safety factor which is higher when said actual transmitting torque is negative than when it is positive. A pulley thrust pressure control valve controls the pressures supplied to the drive and driven cylinders so as to obtain the calculated belt transmitting torque.

Abstract: According to the present invention, the driver's operation quantity and the vehicle running status are measured, the target value of speed ratio or the target value of revolution speed on the input side of the transmission is determined on the basis of the above measured values, and the speed ratio is changed using different algorithms (particularly fuzzy rules) on the basis of the magnitude of deviation between the target value and the actual value.Furthermore, when a vehicle has a continuously variable transmission, a change of at least one of the vehicle acceleration and the shaft torque of a drive wheel is predicted, the engine output torque is controlled on the basis of the prediction, and finite speed ratio characteristics or intermediate characteristics between finite speed ratio characteristics and continuously variable speed ratio characteristics are controlled for the continuously variable transmission.

Abstract: The invention relates to a method of inputting the actual transmission ratio of a continuously variable transmission (CVT=continuously variable transmission) of a vehicle, especially a passenger motor vehicle. For this method, operating points of a shift characteristic field can be assumed which lie on a characteristic line of optimized consumption of a motor characteristic field of a motor of a vehicle. In this method, also operating points of the shift characteristic field can be assumed which lie on a characteristic line of optimized power of the motor characteristic field. The trace of the characteristic line of the shift characteristic field results from the particular selected characteristic line of the motor characteristic field. It is provided that operating points of the shift characteristic field can be assumed which lie on a dynamic characteristic line (c"') of the motor characteristic field.

Abstract: A method for controlling a continuously variable transmission, preferably activated electro-hydraulically, of a motor vehicle equipped with an internal combustion engine, provides for an increase of the transmission ratio while braking and especially while approaching a curve. Adherence to certain boundary conditions for this guarantees a safe driving behavior. The braking effect of the internal combustion engine is used more effectively by increasing the transmission ratio, so that the service brake is relieved of stress. In connection with a transmission-ratio retention mechanism before, during, and after curves, the motor vehicle with a continuously variable transmission controlled by this method can be accelerated nearly without delay when it comes out of the curve.

Abstract: A device for optically providing information pertaining to the value of the quotient of the rates of revolution of two axles contains converters connected to the axles, which converters generate electrical signals which are a measure for the rate of revolution of the respective axles. At least one of the signals is fed to a ladder network of resistances which contains tap-off points which are connected to similar inputs of comparator circuits. The other inputs of the various amplifiers receive as input the signal which is a measure for the rate of revolution of the other axle. The comparator circuits are each coupled to light-emitting elements of which a few, depending upon the quotient of the revolution rates, illuminate. When applied in a vehicle which is provided with a continuously variable transmission, optical information pertaining to the current value of the transmission ratio is thus provided.

Abstract: A CVT control system comprises a controller. The controller determines the desired engine speed as a first function of operator power demand and vehicle speed during a predetermined period involving a momenet when a control element moves off from one of the maximum and minimum reduction ratio command positions, and determines the desired engine speed as a second function of the operator power demand and the vehicle speed during the subsequent period to the predetermined period.

Abstract: An electronically controlled continuously variable transmission system is provided with a driving belt trained over a primary and secondary pulley. The primary pulley is provided on a primary shaft and the secondary pulley is provided on a secondary shaft. Each pulley has corresponding spaced, conical pulley halves and at least one of the corresponding pulley halves is axially movable by respective primary and secondary moving devices. The transmission further includes a primary electronic control system for controlling the transmission ratio and a secondary electronic control system for controlling the belt tension. The primary electronic control system permits the operator to select from fuel economy, sporting, and maximum comfort performance modes. The primary electronic control means controls the transmission ratio in accordance with the performance mode selected. The moving devices include standby operating valves to permit continued operation of the transmission in case of power failure.

Abstract: A change ratio control apparatus is arranged to set the lower limit of the change ratio to values included in a range in which transmission efficiency does not deteriorate due to the reduction in the change ratio if the transmission efficiency of the driving force in the transmission deteriorates in a low load region in which the change ratio is low. Therefore, deterioration in the transmission efficiency can be prevented and the fuel consumption rate can thereby be improved.

Abstract: An electronically controlled continuously variable transmission system is provided with a driving belt trained over a primary and secondary pulley. The primary pulley is provided on a primary shaft and the secondary pulley is provided on a secondary shaft. Each pulley has corresponding spaced, conical pulley halves and at least one of the corresponding pulley halves is axially movable by respective primary and secondary moving devices. The transmission further includes a primary electronic control system for controlling the transmission ratio and a secondary electronic control system for controlling the belt tension. The primary electronic control system permits the operator to select from fuel economy, sporting, and maximum comfort performance modes. The primary electronic control means controls the transmission ratio in accordance with the performance mode selected. The moving devices include standby operating valves to permit continued operation of the transmission in case of power failure.