Abstract: An control apparatus for an automatic transmission includes: a failure shift stage setting section configured to set, to the target shift stage, a shift stage which can be attained in a state in which the one of the solenoids judged that the failure is generated is not energized; and a failure neutral state through section configured to control the solenoids at a predetermined vehicle speed or over so that the automatic transmission is brought to a neutral state, when the target shift stage is a shift stage at which the vehicle speed is suddenly decreased when the solenoids are controlled so that the automatic transmission attains the target shift stage, and to control the solenoids below the predetermined vehicle speed so that the automatic transmission attains the target shift stage.

Abstract: In an automatic transmission of this invention, a determination as to whether or not a failure has occurred in a friction element is made repeatedly while a vehicle is traveling, and control to specify the failed friction element is begun when a vehicle speed falls to or below a predetermined value for the first time following detection of the failure in the friction element (S1, S3). When the failed friction element has been specified (S4, S13, S15, S24, S26, S35, S37), usable gear positions are determined on the basis of the specified friction element, whereupon shift control is performed using only the usable gear positions (S5, S14, S16, S25, S27, S36, S38, S39).

Abstract: An automatic transmission control unit determines whether or not a constantly open failure, in which a switch valve cannot switch a pressure regulating valve and a second hydraulic chamber to a non-communicative state, has occurred on the basis of a parameter (an inertia phase time, for example) representing a dynamic characteristic during a shift from a first gear position to a second gear position. The determination of the constantly open failure is begun after initial variation in the parameter representing the dynamic characteristic during the shift has been eliminated through learning control in which the dynamic characteristic during the shift is caused to approach a target dynamic characteristic.

Abstract: An automatic transmission of a motor vehicle, comprising a plurality of planetary gear units; a plurality of frictional elements, the frictional elements assuming engaged/disengaged condition upon receiving a ratio change instruction thereby to establish a desired speed of the transmission with the aid of the planetary gear units; a deceleration detecting means that detects a deceleration of the motor vehicle; a gear ratio detecting means that detects an actual gear ratio that is actually established in the transmission; and an interlock judgment means that judges whether or not the transmission is subjected to an interlock, the interlock being a condition wherein upon receiving the ratio change instruction, at least one of the frictional elements is brought into unintended engagement.

Abstract: In a stepping motor cooling apparatus for a belt-type continuously variable transmission, a pair of primary and secondary pulleys are disposed inside a transmission case, and a forward/backward switching unit is disposed coaxially to the primary pulley, furthermore, a stepping motor is disposed below the forward/backward switching unit. An inner case originating from the transmission case surrounds a circumference of the forward/backward switching unit. Through the inner case, a dripping hole is formed at an inner case's portion directly above the stepping motor so that working fluid drained from the forward/backward switching unit can drip on the stepping motor. In order to further improve the cooling effect of the stepping motor, a recess portion is formed immediately below the stepping motor at an upper surface of a valve body disposed under the stepping motor.

Abstract: An control apparatus for an automatic transmission includes: a failure shift stage setting section configured to set, to the target shift stage, a shift stage which can be attained in a state in which the one of the solenoids judged that the failure is generated is not energized; and a failure neutral state through section configured to control the solenoids at a predetermined vehicle speed or over so that the automatic transmission is brought to a neutral state, when the target shift stage is a shift stage at which the vehicle speed is suddenly decreased when the solenoids are controlled so that the automatic transmission attains the target shift stage, and to control the solenoids below the predetermined vehicle speed so that the automatic transmission attains the target shift stage.

Abstract: An automatic transmission includes a planetary gear mechanism, an engagement element group including a particular engagement element having first and second pressure chambers, a pressure control valve to regulate the fluid pressure for the particular engagement element, and a selector valve arranged to connect the second pressure chamber with the pressure control valve at a first valve position, and to disconnect the second pressure chamber from the pressure control valve at a second valve position. A shift control section is configured to command a shift operation from a first gear position, to a second gear position, by controlling the selector valve to the second valve position and to supply the fluid pressure to the first pressure chamber, and to judge the selector valve to be in an abnormal state, in accordance with a parameter in the shift operation.

Abstract: An automatic transmission includes a plurality of planetary gears disposed between an input shaft and an output shaft and having a plurality of rotational elements. A plurality of frictional elements are selectively engaged and released for controlling rotations and connections of the plurality of rotational elements in accordance with instructions so as to realize a plurality of gear positions. A rotational speed detecting section detects a rotational speed of a predetermined one of the plurality of rotational elements other than the input shaft and the output shaft. A frictional element release section releases all of the plurality of frictional elements when it is judged that the rotational speed of the predetermined one of the plurality of rotational elements is higher than a predetermined rotational speed.

Abstract: An automatic transmission control unit determines whether or not a constantly open failure, in which a switch valve cannot switch a pressure regulating valve and a second hydraulic chamber to a non-communicative state, has occurred on the basis of a parameter (an inertia phase time, for example) representing a dynamic characteristic during a shift from a first gear position to a second gear position. The determination of the constantly open failure is begun after initial variation in the parameter representing the dynamic characteristic during the shift has been eliminated through learning control in which the dynamic characteristic during the shift is caused to approach a target dynamic characteristic.

Abstract: An automatic transmission of a motor vehicle, comprising a plurality of planetary gear units; a plurality of frictional elements, the frictional elements assuming engaged/disengaged condition upon receiving a ratio change instruction thereby to establish a desired speed of the transmission with the aid of the planetary gear units; a deceleration detecting means that detects a deceleration of the motor vehicle; a gear ratio detecting means that detects an actual gear ratio that is actually established in the transmission; and an interlock judgment means that judges whether or not the transmission is subjected to an interlock, the interlock being a condition wherein upon receiving the ratio change instruction, at least one of the frictional elements is brought into unintended engagement.

Abstract: An automatic transmission comprising a plurality of planetary gears disposed between an input shaft and an output shaft and having a plurality of rotational elements, a plurality of frictional elements selectively engaged and released for controlling rotations and connections of the plurality of rotational elements in accordance with instructions so as to realize a plurality of gear positions, rotational speed detecting means for detecting a rotational speed of a predetermined one of the plurality of rotational elements, other than the input shaft and the output shaft, and frictional element release means for releasing all of the plurality of frictional elements when it is judged that the rotational speed of the predetermined one of the plurality of rotational elements is higher than a predetermined rotational speed.

Abstract: In an automatic transmission of this invention, a determination as to whether or not a failure has occurred in a friction element is made repeatedly while a vehicle is traveling, and control to specify the failed friction element is begun when a vehicle speed falls to or below a predetermined value for the first time following detection of the failure in the friction element (S1, S3). When the failed friction element has been specified (S4, S13, S15, S24, S26, S35, S37), usable gear positions are determined on the basis of the specified friction element, whereupon shift control is performed using only the usable gear positions (S5, S14, S16, S25, S27, S36, S38, S39).

Abstract: An automatic transmission includes a planetary gear mechanism, an engagement element group including a particular engagement element having first and second pressure chambers, a pressure control valve to regulate the fluid pressure for the particular engagement element, and a selector valve arranged to connect the second pressure chamber with the pressure control valve at a first valve position, and to disconnect the second pressure chamber from the pressure control valve at a second valve position. A shift control section is configured to command a shift operation from a first gear position, to a second gear position, by controlling the selector valve to the second valve position and to supply the fluid pressure to the first pressure chamber, and to judge the selector valve to be in an abnormal state, in accordance with a parameter in the shift operation.

Abstract: A solenoid valve control unit which applies overexcitation voltage to a solenoid valve coil corresponding to a supply voltage in an overexcitation period occurring during an initial stage of a duty drive “ON” cycle and the solenoid valve control unit applies a holding voltage to the coil lower than the overexcitation voltage in a holding period occurring during the duty drive “ON” cycle other than the initial stage. Subsequently, the control circuit decreases the effective value of the overexcitation voltage by executing a chopper control effect in the overexcitation period.

Abstract: In a stepping motor cooling apparatus for a belt-type continuously variable transmission, a pair of primary and secondary pulleys are disposed inside a transmission case, and a forward/backward switching unit is disposed coaxially to the primary pulley, furthermore, a stepping motor is disposed below the forward/backward switching unit. An inner case originating from the transmission case surrounds a circumference of the forward/backward switching unit. Through the inner case, a dripping hole is formed at an inner case's portion directly above the stepping motor so that working fluid drained from the forward/backward switching unit can drip on the stepping motor. In order to further improve the cooling effect of the stepping motor, a recess portion is formed immediately below the stepping motor at an upper surface of a valve body disposed under the stepping motor.

Abstract: In a belt-type continuously variable transmission having a speed-change mechanism, a step motor arrangement including a pulley follower engaged with a movable sheave of the primary pulley, a speed-change control valve for controlling a primary pressure to be supplied to the primary pulley, a servo link, and a step motor for driving, by way of the servo link, the speed-change control valve in response to a speed-change command signal, the servo link being connected to the pulley follower to follow a variation in a width of a groove of the primary pulley, wherein the pulley follower, the speed-change control valve and the step motor are arranged side by side in the horizontal direction, and wherein the servo link extends generally horizontally from the pulley follower to interconnect the pulley follower, the speed-change control valve and the step motor.

Abstract: A transmission mechanism of continuously variable transmission in a vehicle comprises a primary pulley and a secondary pulley provided with a first cylinder chamber and a second cylinder chamber, with groove widths being changed by supply of hydraulic pressure, and a belt provided between the pulleys. A hydraulic pressure to the first cylinder chamber is controlled by CVT control unit through a shift control valve according to a driving state of the vehicle, and the second cylinder chamber is continuously supplied with a line pressure. CVT control unit includes an internal memory to retain a heavy-current system fail flag according to the failure information inputted from a motor control unit.

Abstract: A transmission mechanism of continuously variable transmission in a vehicle comprises a primary pulley and a secondary pulley provided with a first cylinder chamber and a second cylinder chamber, with groove widths being changed by supply of hydraulic pressure, and a belt provided between the pulleys. A hydraulic pressure to the first cylinder chamber is controlled by CVT control unit through a shift control valve according to a driving state of the vehicle, and the second cylinder chamber is continuously supplied with a line pressure. CVT control unit includes an internal memory to retain a heavy-current system fail flag according to the failure information inputted from a motor control unit.

Abstract: Described are apparatus and method for monitoring revolution speed values detected by corresponding revolution speed sensors too determine whether at least any one of an engine revolution speed sensor, a continuously variable transmission input axle revolution speed sensor, and a continuously variable transmission output axle revolution speed sensor has failed according to detected values of the engine revolution speed sensor, the input axle revolution speed sensor, and the output axle revolution speed sensor and a detected value of an instantaneous gear shift ratio when a lock-up mechanism is in a lock-up state. If all of three formulae on predetermined correlations are established, all of the sensors are determined to be normally operated. If any one or two of the three formulae are not established, the failure one of the three sensors is identified. The three correlation formulae are based as follows: 1) N.sub.E =N.sub.PRI ; 2) N.sub.PRI =N.sub.SEC .times.CN; and 3) N.sub.E =N.sub.PRI .times.C.sub.

Abstract: A vehicle diagnostic information storage system includes a volatile storage device such as a backup RAM and a nonvolatile storage device such as EEPROM. If a fault occurs, a control section stores data on fault items, and input and output conditions of sensors of a vehicle control system, in the volatile storage device and updates the data in the volatile storage device during a vehicle operation. In response to a switching operation of a vehicle main switch such as a turn-on operation of an ignition switch, the control section transfers the most recent version of updated data from the volatile storage device to the nonvolatile storage device.