Abstract: For an automatic transmission (2), a safety system is proposed in which a virtual reduction ratio is calculated when a driver moves the selector lever from a drive position to neutral and then from neutral back to a drive position. The virtual reduction ratio is then compared with the reduction ratio resulting from a shift characteristic field. In case of divergence, the virtual reduction ratio is assigned to a characteristic field having a linearly constant reduction ratio surrounded by a reduction ratio range. The electronic control unit (5) selects as a set reduction ratio, the one containing in its range the virtual reduction ratio.

Abstract: When a slip control system starts operating, a vehicle speed VSP used for speed change control is simultaneously changed over from a sensor detected vehicle speed VSPSEN to an estimated vehicle speed VSPFL. On the other hand, when the slip control system has stopped, it is first determined whether a speed ratio variation amount, due to the change-over of the vehicle speed used for speed change control from the estimated vehicle speed VSPFL to the sensor detected vehicle speed VSPSEN, is less than a permissible amount. When it is determined that the speed ratio variation amount is smaller than the permissible amount, the vehicle speed used for speed change control is changed over from the estimated vehicle speed VSPFL to the sensor detected vehicle speed VSPSEN. By performing this change-over, a sharp variation of the vehicle speed used for speed change control is suppressed, and a sharp variation of the speed ratio leading to shocks or slipping is suppressed.

Abstract: A method is provided for determining an acceptable torque level to be applied to at least one clutch pack (of an automobile) which includes the requirement of internal slip to transmit torque. The automobile includes a plurality of wheels. A velocity is sensed at each of the plurality of wheels of the automobile. A speed information value is calculated. The speed information value is a function of the sensed velocities at each of the plurality of wheels. The speed information value is then compared with a calibration table. Finally, the acceptable torque level is determined primarily from the calibration table based on the speed information value.

Abstract: A system for controlling downhill vehicle operation includes an electronically actuatable engine compression brake unit associated with an internal combustion engine, an electronically controllable turbocharger boost pressure adjustment device, electronically actuatable service brakes and a transmission including a number of automatically selectable gear ratios, wherein each of these components are coupled to a control computer. In accordance with one aspect of the present invention, the control computer is operable to detect a potential runaway vehicle condition and control any one or combination of engine compression brake activity, turbocharger boost pressure, service brake activity and automatic transmission shifting to thereby provide for a controlled descent down a negative grade and thereby prevent a runaway vehicle condition.

Abstract: The driving force control system calculates a target driving force Tt* and then calculates a target engine torque Te* from a target driving force Tt* and a target calculated engine torque gear ratio. When the transmission is not shifting, the driving force control system uses a gear ratio determined by the gear position as the target calculated engine torque gear ratio. When the transmission is shifting, the driving force control system uses an actual gear ratio calculated from the input and output rotational speeds. This gear ratio switching control makes it possible to vary the target engine torque Te* gradually in response to the change of the actual gear ratio during shifting. Thus, a dip in the output torque is eliminated, and the shifting shock is mitigated to a satisfactory level.

Abstract: A shift control system for a continuously variable transmission, in which a road load on a vehicle is detected, the lower limit speed is set according to the detected road load, in which a target input speed, as set according to the running state of a vehicle, is restricted with the set lower limit speed, and in which the gear ratio of the continuously variable transmission is controlled so that the actual input speed may be equal to the target input speed restricted. The target input speed is restricted after the actual input speed is more than the lower limit value, when the road load is light, and said target input speed is restricted irrespective of the actual input speed when the road load is heavy.

Abstract: In an infinite speed ratio transmission comprising a continuously variable transmission (2), reduction gear unit (3) and planetary gear set (5), the speed ratio of the continuously variable transmission (2) is controlled by a step motor (36). A range selected by a selector lever (86) is detected by a sensor (84). When the selected range has changed from a stationary range to one of a forward motion range and a reverse motion range, a microprocessor (80) first drives the step motor (36) to a predetermined position (S48, S54).

Abstract: A method for ratio control for a continuously variable belt drive transmission with electrohydraulic control by means of a control loop with a linear PID controller with the theoretical ratio of the variator iv_theor.

Abstract: A multiple-ratio automatic transmission comprising a first multiple-ratio gear unit and a second simple planetary gear unit arranged in series in a torque flow path, each gear unit having a reaction brake that can be selectively activated and deactivated to effect a ratio change as the first gear unit is upshifted and the second gear unit is downshifted, ratio changes in each gear unit being effected by pressure-operated clutches and brakes, the brakes having opposed pressure-apply and pressure-release chambers. Separate exhaust flow paths are provided for a reaction brake release chamber and for a companion pressure-operated clutch. A pressure modifier valve circuit is provided for increasing the rate of response to a command for applying and releasing the clutch.

Abstract: The invention relates to a system for adjusting a transmission ratio in a transmission built into a motor vehicle. The system has at least two determination elements for determining values based on different determination modes with these values representing individual driving situations of the motor vehicle. An administrator calls up the values from the determination elements and stores the values. The administrator outputs individual ones of the values in response to a command whereupon the transmission ratio is adjusted at least in dependence upon the outputted ones of the values. The invention affords advantages with respect to expandability, functionality and reusability.

Abstract: A transmission includes a transmission input speed sensor which generates transmission input speed signals indicative of an input speed to the transmission and a transmission output speed sensor which generates transmission output speed signals indicative of an output speed of the transmission. The transmission further includes a controller operable to receive the transmission input speed signal and the transmission output speed signal and determine a transmission ratio based on the transmission input speed signal and the transmission output speed signal. The controller is further operable to calculate a rate of change of the transmission ratio and initiate a transmission range shift based on the transmission ratio, the rate, and a shift completion ratio such that the transmission range shift is completed when the transmission is at the predetermined shift completion ratio.

Abstract: In a method of controlling a transmission ratio of a continuously variable toroidal transmission, a holding force for an intermediate roller is pilot-controlled as a function of the torques acting on the toroidal disks and of the pivoted position of the intermediate roller, and/or the adjustment path of the intermediate roller is fed back statically or dynamically into a control circuit.

Abstract: The invention relates to a method for determining a transmission ratio for an automatic transmission arranged in the drive train of a motor vehicle. Operating parameters of the vehicle and especially of equipment arranged in the drive train are made available in a control apparatus to determine the transmission ratio. The invention provides that the transmission ratio (i) of the transmission is determined in dependence upon an instantaneous vehicle load.

Abstract: An electronic control system for an automatic transmission has an electronic control unit including a CPU and a memory. The control program is programmed based on an object-oriented programming. An object such as a domain control unit or individual control parts are provided for driving a corresponding linear solenoid valve. A shift request output unit determines types of required shift and outputs a shift request message including the shift type. The domain control unit determines a method to be executed in response to the shift type ID. Preferably, the shift request output unit further determines whether the shift is a single shift or a multiple shift and whether the shift is a normal shift or a special shift. These determination results are also included in the shift request message, so that the domain control unit varies the method to control the linear solenoid valves.

Abstract: A learning controller makes learning correction based on a time tST between start of a shift control routine and detection of start of a change in rotational speed of the transmission input shaft and further based on the amount of rotational speed change &ohgr;S′ at the detected start of the rotational speed change. When the time tST is longer than a basic time and when the rotational change amount &ohgr;S′ is too large, it is determined that a servo piston has not been sufficiently advanced and the shift control is corrected so that the time tST is lengthened. When the time tST to the detected start of the rotational speed change &ohgr;S′ is too small, it is determined that, while the piston has been advanced properly, the target engagement pressure PTA in torque phase control is too low because of a miscalculation, and the shift control is corrected so that the target engagement pressure is raised.

Abstract: A continuously variable transmission of an automobile which varies the drive ratio arbitrarily between an input axis and an output axis is combined with a traction control device for example which performs braking corresponding to vehicle running conditions and irrespective of the accelerator pedal depression. A microprocessor calculates the vehicle speed from the rotation speed of the output axis, calculates the target drive ratio depending on the vehicle speed, and controls the drive ratio of the continuously variable transmission to be equal to the target ratio. When the brake operation device performs braking, fluctuation of the drive ratio based on the rotation variation of the output axis is prevented by the correction of the drive ratio in the upshift direction.

Abstract: A hand-off state determination section 73 estimates torque Th exerted on the steering handle by a driver. When the steering handle is in the hand-off state in which the torque is small, switching is effected to the side of compensator 75 having smaller gains set, so as to stabilize a steering control system.

Abstract: The invention is directed to the automatic determination of a quantity which represents the rpm ratio between the transmission and the wheels. For this purpose, first and second rpm values are first detected which represent the rpm of at least one wheel and the rotational speed of a transmission component. Furthermore, a driving state quantity is formed which represents the instantaneous driving state of the motor vehicle. The essence of the invention is that a pregiven driving state can be determined when the formed driving state quantity indicates an essentially steady state driving state. The determination of the rpm transmission ratio which is sought takes place in dependence upon the detected rpm values when the pregiven operating state is detected. Furthermore, the invention relates to a stepped method which, for example, ensures a rapid determination of the differential transmission ratio after a transmission control apparatus is newly built in.

Abstract: A method of shifting a transmission having both a hydrostatic portion, including a variable pump (15), and a hydraulic motor (29), and a mechanical transmission (33) portion, including a shift cylinder (37). The method includes relieving the output torque of the motor (29), shifting the mechanical transmission to neutral, and controlling the. displacement of the pump (15) to synchronize motor output speed with the required input speed to the desired gear ratio of the mechanical transmission (33). Then fluid flow to the shift cylinder (37) occurs to shift to the desired gear ratio. The shifting method includes a series of steps in which the feasibility of the prospective shift is determined, and only when the prospective shift can be completed, without detriment to the operation of the vehicle, will the shift be completed. As a result, the shifting between low gear and high gear can occur without bringing the vehicle to a stop each time.

Abstract: In a continuously variable transmission for use with a vehicle comprising an actuator for continuously varying a speed change ratio, a target speed change ratio is set according to the vehicle running conditions and a real speed change ratio of the transmission is detected. A proportional value which is directly proportional to a difference between the target speed change ratio and real speed change ratio, and an integral value of the difference therebetween, are calculated. When the integral value is not within a preset range, the integral value is corrected to a value within the range, and the actuator is driven based on the sum total of the proportional value and the corrected integral value. In this way, a command exceeding the response capability of the actuator is prevented from being output to the actuator, and overshoot of the speed change ratio is prevented.

Abstract: A transmission control system of an automotive vehicle with a continuously variable automatic transmission, comprises an electronic transmission control unit which detects an acceleration of a drive wheel of the vehicle, and compares the acceleration of the drive wheel to a predetermined acceleration value. The control unit operates to inhibit only the upshifting action by preventing a speed ratio of the continuously variable automatic transmission from being upshifted toward a speed ratio less than a predetermined upshift limiting threshold.

Abstract: A control for preventing damage to a vehicular driveline (10) during attempts to launch a vehicle from a stopped condition while engaged in an inappropriate start ratio. The control involves sensing engaged transmission ratio (GR) and vehicle speed (OS) to determine if the vehicle is being launched while the transmission is engaged in an inappropriate start ratio and, if such conditions are sensed, issuing command signals to the engine controller (36) to cause engine output torque to be limited to a predetermined value, preferably a value less than 50% of maximum engine output torque.

Abstract: The invention relates to a method of adjusting the transmission ratio of a continuously variable gear. The position of a current operating point (B_akt) in a predetermined driving range is constantly adjusted in accordance with the driving situation. The position of the operating point is also determined by range boundaries (UG, OG) which can be varied in accordance with the driving resistance and the driver's manner of driving. The method is characterized in that it simplifies development and application.

Abstract: The invention concerns a drive system, especially for a vehicle, with a drive unit, especially an internal combustion engine, a transmission with variable transmission ratio between drive unit and drive, and especially with a continuously variable transmission ratio or one variable in fine gradations, at least one additional unit driven by the drive unit, especially an electric generator, a control, which selects the transmission ratio within a range of possible transmission ratios, so that the highest possible efficiency is achieved with joint consideration of the individual efficiency functions of the vehicle drive and the additional unit(s) and their drive, in which the individual efficiency functions are incorporated in the total efficiency with a weight corresponding to the power fraction of the vehicle drive and additional unit(s). The invention is also geared toward a corresponding method.

Abstract: A controller (61) calculates a transient target speed ratio based on a final speed ratio set according to a vehicle running condition and second order delay time constant gains (75, S99), and control a speed ratio of a continuously variable transmission to the transient target speed ratio via an actuator (4) (87, S103). The controller (61) also calculates the deviation between the final target speed ratio and transient target speed ratio (74, S95), and determines the second order delay time constant gains based on the deviation (74, S98). Preferably, the gains are determined so that the response rate is slower the larger the deviation (74, S134, S135, S136, S137, S139, S140, S141).

Abstract: A gyration angle .phi. of a power roller (3) of a toroidal continuously variable transmission (10) is made to vary via a step motor (4) and control valve (5). A controller (61) calculates a feedback control amount v of a step motor (4) so that a real speed ratio i of the transmission (10) coincides with a target speed ratio i*. The controller (61) calculates a command value u by correcting a control value v based on a non-linear relation between the gyration angle .phi. and the real speed ratio i, and controls the actuator (4) based on the command value u.

Abstract: A controller for a continuously variable transmission of a vehicle sets a command speed ratio so that a real speed ratio approaches a target speed ratio which is set according to running conditions including throttle opening. When an upshift is performed, this controller determines, from the variation of throttle opening, whether the upshift is due to a decrease in throttle opening or whether it is another type of upshift. When it is determined that the upshift is due to throttle opening decrease, a response rate of the command speed ratio relative to the target speed ratio immediately after start of speed change is temporarily increased, and subsequently slowly decreased.

Abstract: In a disengagement side control, in a power on state, a disengagement side pressure P.sub.W is output, P.sub.W being set higher than a base pressure dependent on input torque, and a disengagement side frictional engagement element is engaged and maintained. In a power off state, a disengagement side pressure lower than the base pressure is output, and the disengagement side frictional engagement element slips. In the disengagement side control, when the vehicle driving state is changed from the power off state to the power on state, the disengagement side pressure P.sub.W is changed from that for a slip state to that for a maintain state.

Abstract: A control apparatus and method for an automatic transmission that prevents incorrect determination of the start of a gear change inertia phase caused by bounding of an input shaft speed, and that prevents delay of the detection of the start of the inertia phase. A working fluid pressure of the frictional element is feedback-controlled in an inertia phase of a gear change transition of a speed-changing gear mechanism, wherein the input shaft speed of the mechanism changes along with an engaging operation of a frictional element of the mechanism. When it is determined that a starting point for the inertia phase control has been reached, inertia phase control is initiated. After a predetermined determination interval subsequently elapses, it is determined whether the inertia phase control should continue.

Abstract: A shift control apparatus outputs a command transmission ratio to a continuously variable transmission (CVT) to control a real transmission ratio of the CVT. The shift control apparatus comprises a shift mode determining section determines whether an actually selected shift mode is an automatic upshift or a power-down upshift (foot-release upshift), on the basis of the result of a previously selected shift mode, a difference between a final objective transmission ratio and a transient objective transmission ratio and a rate of change in the transmission ratio per time. The dynamic characteristic selecting section determines the dynamic characteristic according to the determined shift mode.

Abstract: A variable control device which controls the rotations of a step motor in a continuously variable transmission and maintains the variable ratio is provided with a feed back control system and a feed forward control system. These control systems are switched on the basis of the driving conditions. The feed back control is provided with an actual pulley compensator 108b which calculates the external disturbance compensation from the actual pulley ratio (Aip) and a command value external disturbance compensator 108a which calculates the external disturbance compensation from the command pulley ratio. When switching from open loop control to feed back control, the actual pulley ratio compensator 108b is initialized to the actual variable ratio (Aip). On the other hand, the command value compensator 108a is initialized to the command pulley ratio (ip.sub.R).

Abstract: A controller for a motor vehicle device, such as a transmission. The transmission ratio is automatically controlled in dependence on at least the accelerator pedal position and the driving speed, using stored characteristic maps. A fuzzy logic circuit has at least one rule base. Various signals, which characterize driving states and the load state of the motor vehicle, are evaluated by the fuzzy logic circuit and control signals are generated in response. The control signals define the transmission ratio. At a predefined dynamic driving state, an additional control signal is generated by the fuzzy logic circuit, by means of which signal a change to the transmission ratio is carried out. That change is independent of the respective characteristic map. Dynamic driving states of this type are, for example, the occurrence of an impermissible wheel brake slip or driving down relatively long downhill gradients.

Abstract: A method and apparatus for controlling a transmission for use with an automotive vehicle including an engine. The transmission coupled to the engine for transmitting a torque inputted thereto from the engine to produce an output torque at a continuously variable speed ratio. A target value for the speed ratio is calculated based on vehicle operating conditions. A rate at which the speed ratio changes to the calculated target value is calculated. An upper limit for the rate is calculated to satisfy such a condition that the output torque is substantially equal to or greater than zero. The rate of change of the speed ratio is limited to the upper limit when the calculated rate of change of the speed ratio is greater than the upper limit.

Abstract: A continuously variable transmission control system determines the desired speed ratio for a continuously variable transmission from various input data received from the vehicle and operator. The desired speed ratio is compared with a commanded speed ratio to provide an error signal which establishes a new commanded speed ratio for the continuously variable transmission. The comparing process of desired speed ratio to commanded speed ratio is repeated until the error signal is substantially null. Also, the control provides an adaptive modifier for the actuator of the continuously variable transmission such that a comparison of actual transmission ratio to commanded speed ratio will determine if an adaptive modification is necessary. The control further provides a step control function which is operable when the ratio of the continuously variable transmission is moving toward an underdrive ratio.

Abstract: A method and a circuit configuration for gear detection in a motor vehicle transmission detect a signal corresponding to an input rpm and a signal corresponding to an output rpm of the transmission. A quotient of the output rpm to the input rpm is formed. A gear that has been engaged is detected from this quotient and from a known gear ratio of the transmission. A variation over time of the ratio of the output rpm to the input rpm of the transmission is ascertained and compared with a limit value. If the limit value is exceeded, a determination is made that no gear has been engaged.

Abstract: A method and apparatus for shuttle shifting a power transmission are disclosed. The transmission is of the type including a plurality of intermeshing gears and a plurality of clutches associated with the gears. The clutches are engageable in predetermined combinations to place the transmission in various gear ratios. A control system permits the transmission to be shuttle shifted from forward to reverse gear ratios and vice versa, taking into account the vehicle speed and the target gear ratio to be engaged following the shuttle shift. If the shuttle shift request prior to expiration of a preset time following movement of a command device from a directional position, the transmission is placed in a neutral condition. If the vehicle speed is greater than a maximum allowable shuttle shifting speed upon request of the shuttle shift, the transmission is placed in a neutral condition.

Abstract: A continuously variable transmission in a motor vehicle is regulated using a controller comprising a first control circuit as a speed controller for regulating the transmission input speed as the product calculated from the transmission output speed and the transmission ratio, complete with a summation element at the controller input as well as with a control element, and a second control circuit post-connected to the first control circuit as a speed gradient controller for regulating the time derivative of the transmission input speed, complete with a summation element at the controller input.

Abstract: A downshift control device for an automatic transmission is provided in which the transmission is shifted down by releasing an oil pressure from a first engaging element that has been engaged while applying an oil pressure to a second engaging element that has been released.

Abstract: A control system and method for a semi-automatic mechanical transmission system (10) is provided for allowing operator request for direct shifts into a preselected default start ratio (GR.sub.DS) or into a dynamic best gear ratio (GR.sub.DB) under certain predefined conditions. The dynamic best gear ratio, under at least certain vehicle operating conditions, is the higher of a test best gear ratio (GR.sub.TB =ES.sub.TARGET /OS), determined as a function of vehicle speed (OS) and a target engine speed (ES.sub.TARGET), or the default start ratio.

Abstract: In order to precisely determines the time to start feedback control of line pressure during a shifting period, a shift control computer calculates an effective gear ratio Ge=Nt/Nos at the time of an shift instruction based on input shaft rotational speed Nt and detected vehicle speed Nos and then calculates a parameter F=Nos.times.Ge-Nt indicating the point to start feedback control based on the input shaft rotational speed Nt, the detected vehicle speed Nos and the effective gear ratio Ge. By comparing the calculated parameter F with a predetermined value .DELTA.Nt, hydraulic pressure at the start of shift operation is maintained if F<.DELTA.Nt and, if F.gtoreq..DELTA.Nt, feedback control is performed to cause the input shaft rotational speed Nt to vary in a predetermined manner.

Abstract: A multiple ratio transmission having a main gear unit with at least three forward driving ratios and a single reverse drive ratio and a simple planetary gear unit in series with the main gear unit, the simple planetary gear unit being downshifted and the main gear unit being upshifted on an upshift from a first intermediate ratio to a higher intermediate ratio, the simple planetary gear unit being upshifted and the main gear unit being downshifted on a downshift from the higher intermediate ratio to the first intermediate ratio, the initiation of the inertia phase of the upshifting mean gear unit on an overall automatic transmission ratio upshift triggering the beginning of the release of a reaction element of said simple planetary gear unit upon downshifting of said simple planetary gear unit.

Abstract: A method and apparatus for controlling a transmission for use with an automotive vehicle including an engine. The transmission coupled to the engine for transmitting a torque inputted thereto from the engine to produce an output torque at a continuously variable speed ratio. A target value for the speed ratio is calculated based on vehicle operating conditions. A rate at which the speed ratio changes to the calculated target value is calculated. An upper limit for the rate is calculated to satisfy such a condition that the transmission input torque is less than a maximum value below which there is no danger of damaging the transmission. The rate of change of the speed ratio is limited to the upper limit when the calculated rate of change of the speed ratio is greater than the upper limit.

Abstract: A control system is provided for a vehicle with a power source connected to a transmission, a transmission controller, a clutch and a clutch control element for controlling clutch engagement and disengagement. The control system includes a gear shift lever with a neutral and non-neutral position, a relay circuit coupled to the gear shift lever and the clutch control element that responds to neutral and non-neutral signals from the gear shift lever, and a limp-home switch coupled to the clutch control element to control the application of power to the clutch control element by providing power to the clutch control element when the switch is actuated and the gear shift lever is not in neutral and interrupting power to the clutch control element when either the limp-home switch is not actuated or the gear shift lever is in the neutral position.

Abstract: A steady state transmission ratio Base i is computed from a vehicle speed VPS and a throttle opening TVO (S1). An output shaft revolution speed No of the transmission and a current transmission ratio i are detected (S2, S3). A coefficient TTINR is computed from a difference or a ratio or the like between the steady state transmission ratio Base i and the current transmission ratio i (S4). Then, from the current transmission ratio i, the output shaft revolution speed No and the coefficient TTINR, a shift speed SV=TTINR/(IE.times.i.times.No) is computed (S5). Then a shift control is performed in accordance with the shift speed SV so as to approach to the steady state transmission ratio Base i (S6.about.S9). Thus, the shift speed during shifting in a continuously variable transmission is controlled in consideration of inertia torque.

Abstract: A method and apparatus for operating a power transfer device such as a vehicle transfer case having, shaft speed sensors, a two speed (high-low) drive assembly, an electrically, pneumatically or hydraulically operated shift operator and a microprocessor comprising the steps of sensing the speeds of the transfer case input shaft and output shaft, calculating the rate of change (.DELTA.S/.DELTA.t) of the speed of the input shaft, predicting, based upon such rate of change, a time when the input shaft and the output shaft will be synchronized and commencing movement of such shift operator at a time prior to such synchronization in order to effect engagement of such clutch into high gear at substantially the instant of synchronization.

Abstract: A method of establishing an adaptive pressure term in an automatic transmission having a pressure command developed from a base line pressure term and an adaptive pressure term extends implementation of adaptive pressure corrections during non-ideal periods of operation such as low temperatures, short operating cycles and driver variations by establishing an adaptive pressure term proportional to a measure of confidence in a pressure correction term calculated at each ratio change of the transmission. The measure of confidence is determined according to a variety of functions of predetermined powertrain operating parameters and measures of criticality.