Abstract: A power train for use in motor vehicles has an infinitely variable transmission with two adjustable sheaves, an endless flexible torque transmitting element trained over the sheaves, and at least one hydraulic adjusting unit for each of the sheaves. The adjusting units receive pressurized fluid from a pump and the pressure of such fluid, and hence the extent of frictional clamping engagement between the sheaves and the flexible element, is regulated by a torque sensor including a plenum chamber with an outlet having an effective cross-sectional area which is variable in dependency upon variations of torque being applied to the torque sensor by the engine of the vehicle. The energy of fluid leaving the plenum chamber is used to operate a jet pump which draws fluid from a source for lubrication and/or cooling of the transmission and/or one or more clutches forming part of the power train.

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 control system for a vehicle having an engine-CVT drivetrain suspends the ratio change command during a predetermined period of time from operator's command to request the vehicle to move off from a standstill position.

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: 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 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 relates to a process for controlling a change of the transmission ratio (ue) in an infinitely variable transmission, which simulates a stepped transmission. A basic shifting time is determined separately for each shifting position and direction. In addition, a rotational speed factor, is used to take into account the change of the rotational input speed of the transmission caused by the change of the transmission ratio, and a lead factor reflects the lead existing at the transmission input. Shifting of the infinitely variable transmission is then performed as a function of the basic shifting time, the rotational speed factor and the lead factor.

Abstract: A controller (17) obtains a target input rotating speed (N.sub.is) based on a vehicle running speed (VSP) and a throttle valve opening degree (TVO), drives a motor (23) by the use of a corresponding instruction value, and operates a speed change control valve (21) through a link (22). The controller (17) makes the motor (23) rotate to a hardware limit position in a side corresponding to a lower speed ratio side when the vehicle is in a stopping condition, and then makes the motor (23) rotate in the counter direction to return to a position corresponding to the lowest speed change ratio. On this occasion, the instruction value of the motor (23) is initialized to "0" corresponding to the lowest speed change ratio. When the vehicle is in a running condition, an actual speed change ratio is calculated, from which the motor position is inferred. Then, the instruction value of the motor (23) is initialized as a value corresponding to the inferred position thereof.

Abstract: An improved lockup control system for a lockup-type torque converter for automotive vehicle performs a coasting lockup control of a lockup clutch with minimized response delay of lockup releasing control and suppressed lockup releasing shock upon acceleration of the vehicle. The control system includes a controller that is operative when the driving condition of a vehicle as represented by the throttle valve opening and the vehicle speed is judged to belong to a lockup region. The controller reduces the differential pressure across the lockup clutch to a lower limit value within a range in which the clutch can be prevented from slips. Thus, when the vehicle is reaccelerated and the driving condition shifts out of the lockup region, the reduction amount of the differential pressure is minimized to mitigate the response delay in the lockup releasing control.

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 CVT is operated in both a continuously-variable mode and in a simulated stepped-ratio mode. In the stepped ratio mode, the highest preset transmission ratio (e.g., "first gear"), is variable and responsive to vehicle driving conditions. A control senses a low vehicle speed operating condition and adapts the highest ratio to reduce the step up to the next preset ratio. The control also senses a vehicle start condition and adapts the highest ratio to the current engine torque to improve drivability.

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 combined transmission assembly and monitoring system for indicating the operating condition of the transmission assembly includes a transmission assembly having an input shaft, an output shaft, and a plurality of components for connecting the output shaft for rotation at a predetermined speed relative to the input shaft, a sensor attached to a portion of the transmission assembly, the sensor being responsive to vibration of the portion of the transmission assembly for generating signals indicative of the sensed vibration, and a controller for receiving the signals from the sensor and generating an indication of the operating condition of the transmission assembly based on the vibration of the portion of the transmission assembly. Preferably the sensor is adapted to detect both the frequency and magnitude of vibration of the transmission assembly and to generate signals indicative of the sensed frequency and magnitude of vibration.

Abstract: A method is described for controlling the power train of a work vehicle. The power train includes an engine with a fuel injection control and an infinitely variable transmission. The method include first determining an initial engine speed, an initial wheel speed, the actual engine speed, and the actual wheel speed. To improve comfort and reduce fuel consumption and emissions two steps are performed. First, the transmission ratio of the infinitely variable transmission will be increased if the actual engine speed is less than the initial engine speed, or decreased if the actual engine speed is greater than the initial engine speed. Second, while the transmission ratio remains constant, the engine speed will be adjusted until the engine speed is the same as the initial engine speed.

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: 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 method for controlling a preferably electrohydraulically actuated continuously variable transmission of a motor vehicle equipped with an internal combustion engine provides, in and ahead of curves, a retention of the last gear ratio set. The gear-ratio determination is initiated when the accelerator pedal is released rapidly in coasting operation. The gear transmission determination is suspended as soon as, after expiration of a time interval following recognition of acceleration, no curve is being traversed. If, during expiration of the time interval, coasting operation is detected again, the gear transmission determination is maintained for an additional time interval. Upon termination of the gear-ratio determination, a relatively slow adaptation of the gear ratio to the setting corresponding to the control curve RKLj takes place.

Abstract: A continuously variable belt and sheave drive mechanism for use with an internal combustion engine in an automotive vehicle driveline including a simplified valve system that responds to control commands from a microprocessor that receives input data from engine, turbine and output shaft speed sensors, an engine throttle position sensor and a sheave position sensor as well as other driveline variables so that the operating characteristics of the transmission are matched to the speed torque characteristics of the engine to produce improved driveline efficiency and performance while permitting the engine speed to be related functionally to the throttle position as well as vehicle speed and permitting engine speed to increase when rapid acceleration is desired while minimizing changes in engine speed for small throttle position variations.

Abstract: A method for controlling an electro-hydraulically operated infinitely variable transmission of a motor vehicle which is driven, in particular, by an internal-combustion engine, provides a control of the infinitely variable transmission according to several characteristic control curves. The characteristic control curves are selected corresponding to a driving activity which evaluates the driver's driving style or his action with respect to the control of the motor vehicle caused by a traffic situation. The characteristic control curves cover, at least in steps, the range between a characteristic control curve permitting the consumption-optimized operation of the motor vehicle and a characteristic control curve which permits the power-optimizing operation of the motor vehicle.

Abstract: With an engine wherein the setting of a target air-fuel ratio is changed in accordance with operating conditions, and the air-fuel ratio of the engine intake mixture is controlled in accordance with the target air-fuel ratio, a gear ratio in an automatic continuously variable transmission fitted to the engine is forcibly changed towards a ratio which suppresses changes in vehicle drive torque, at the time of changing the setting of the target air-fuel ratio. As a result even with a rapid change in engine output torque following a change in the target air-fuel ratio, a rapid change in the vehicle drive torque can be suppressed, so that vehicle driving stability can be improved.

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 apparatus for adjusting the output torque, or the output power, of a continuously variable transmission in vehicles propelled by combustion engines to a predetermined value, has a calculating unit (15) for setting a target value for the output torque or power M ab Soll as a function of an accelerator position (14;2) and vehicle speed (nab). An engine torque target value is calculated (units 18, 19, 20) as a function of the so value and an actual or instantaneous transmission ratio value or speed (u n ist). Target values of a transmission ratio are calculated in a unit (16), including a look-up table or an algorithm for storing or calculating transmission ratio values as a function of transmission output speed and of the accelerator pedal position (14;2) or the transmission output torque target value in accordance with a predeterminable engine operating strategy (e.g. optimum fuel efficiency, or performance, or driving comfort.

Abstract: A control apparatus for controlling a stepless transmission which changes the effective diameter between a primary pulley and a secondary pulley by cyclically controlling a change rate toward a target value to be set in advance based upon the characteristic set in advance. The apparatus detects the throttle opening degree TVO, a RANGE signal, the revolutional frequency of the secondary pulley Ns and the like, and detects whether the vehicle is in a transitional status of an acceleration operation or a deceleration operation. At a point in time during the transitional period, the apparatus sets a first target value based upon the signals such as the TVO signal, the RANGE signal and the Ns signal, and sets a second target value based upon the difference between the first target value set in the current control cycle and the second target value set in the previous control cycle, at the same time, sets a change in the second target value to be smaller than that in the first target value.