Aisin Seiki Kabushiki Kaisha

Kabushiki Kaisha Toyota Chuo Kenkyusho

Aisin Seiki Kabishuki Kaisha

Masato Shimei

Shigeki Goto

Yoshitami Saitou

Tetsuhiro Miyazawa

Suguru Futamura

Takahiro Sakai

Nobuyuki Isono

Yoshiyuki Onimaru

Hiroyuki Yamaguchi

Shigeo Takahashi

Kiyoharu Takagi

Toshiaki Ishiguro

Katsuhiko Hattori

Masanori Mori

Choji Furusawa

Yasuo Shirai

Masahiko Nakagawa

Kokichi Kato

Masayuki Tomita

Takanao Suzuki

Atuo Okumura

Munenori Kamino

An oil pressure control apparatus for an automatic transmission includes a calculating means for calculating, on the basis of a transmission output shaft rotational speed, at a time of a shift operation from a neutral shift stage to another shift stage appropriate to a vehicle driving condition, output-side rotational speeds of frictional engagement elements, and a shift stage selecting means for selecting a shift stage, in which oil with line pressure is supplied to a first frictional engagement element, from among the frictional engagement elements, and in which a minimum difference exists between the output-side rotational speed of the first frictional engagement element and an input-side rotational speed of a second frictional engagement element, from among the plural frictional engagement elements. The second frictional engagement element corresponds to the first frictional engagement element for the shift stage selected by the shift stage selecting means.

Oil pressure control apparatus for an automatic transmission

An automatic transmission system for a vehicle includes a rotational speed detector for detecting a variation of a rotation number of driving torque transmitting member when a friction engagement element, which has been disengaged based upon oil pressure controlled by a control unit, a side of which has been transmitted with the rotation of the driving torque transmitting member, and the other side of which is locked not to be rotated during the vehicle at a stationary condition, is controlled to be engaged, wherein an oil pressure characteristic value of the friction engagement element is learned by the control unit based upon the variation of the rotation number of the driving torque transmitting member when the friction engagement element is initially engaged.

Automatic transmission system and method for controlling thereby

A lock-up control method of an automatic transmission for making the optimum lock-up control correspond to a shift control. In the lock-up control method of the automatic transmission in which the fastening force of a lock-up clutch is temporarily dropped to cause the lock-up clutch to slip in shifting the automatic transmission, the maximum value of a rate of change of speed of an input element is found while shifting the automatic transmission, the fastening force of the lock-up clutch is corrected so that a deviation between the maximum value and a target rate of change of speed of the input element is zeroed and the lock-up clutch is fastened by the corrected fastening force in the next shift.

Lock-up control method of automatic transmission

A shift control unit which improves the shift feeling of an automatic transmission includes an operation control device for placing a frictional engaging element in a slow drain state during a timing time decided by a timing time deciding device and in a quick drain state when the timing time has elapsed. The shift control unit is provided further with a computing device for computing the power-off engine speed necessary for outputting a small range upper limit value of a turbine torque from a number of revolutions of the turbine of the torque converter and from the performance characteristic of the torque converter, and an auxiliary operation control device for comparing the power-off engine speed and actual engine speed and for running the operation control device when the actual engine speed is equal to or greater than the power-off engine speed to place the frictional engaging element into the quick drain state immediately without running the operation control device when the actual engine speed is below the power-off engine speed.

Shift control unit of automatic transmission

A control device of an automatic transmission comprises a controller which detects accel off caused by the release of accelerating owing to the accel stamping in which lock-up clutch is released, and which proceeds command which releases the operation thereof or releases temporally the operation thereof to an exhaust brake device when it is decided that the exhaust brake is in operation. When accel off is suddenly conducted at the time of accelerating in which the lock-up clutch is not engaged the phenomenon in which the speed ratio at the torque converter is prevented from occurring by releasing the exhaust brake by the controller. Accordingly, the engaging operation of the lock-up clutch is conducted easily and it is possible to let the engine brake work. When the down shift of the automatic transmission or accel off is conducted a the time of using the exhaust brake, it is possible to conduct the engagement, of the lock-up clutch easily and let the engine brake work effectively.

Control device for releasing an exhaust brake and engaging a lockup

An automatic transmission control device for use in controlling an automatic transmission that includes a plurality of friction engaging devices disposed between the rotational shaft of the engine and the output shaft in order to control gear ratios includes a control device which controls the engaging operation and the disengaging operation of each of the friction engaging devices. The control device changes the time when the engagement side friction engaging device begins to engage based on the gear ratio from which the power-on down shift operation is being made and the gear ratio to which the power-on down shift operation is being made. Thus, in the case of a 4.fwdarw.2 power-on down shift operation the time when the engagement side friction engaging device begins to engage is longer than during a 3.fwdarw.2 power-on down shift operation. In this way, temporary increases in the engine rotational speed are prevented and shift shock is avoided.

Automatic transmission control device

An automatic transmission includes the transmission control device which sets a control time upon changeover from the second gear condition to the third gear condition during which the brake device is maintained in the engaged condition until changing to the disengaged condition. The transmission control device also adds a compensating time to the control time upon changeover from the second gear condition to the third gear condition in certain circumstances such as when changeover from the second gear condition to the third gear condition follows operation under the first gear condition, and when change over from the second gear condition to the third gear condition follows vehicle operation under the second gear condition for a period exceeding a predetermined time (e.g., 10 seconds).

Automatic transmission

A control apparatus for an automatic transmission having a set of frictional engagement elements arranged to be selectively engaged or disengaged in shift-up operation of the transmission, and a shift timing valve arranged to be switched over by hydraulic pilot pressure applied there-to under control of a solenoid valve for switching over discharge of fluid under pressure from one of the frictional engagement elements to be disengaged in the shift-up operation from a slow-drain condition to a quick-drain condition. The control apparatus is designed to detect a drive torque of a vehicle engine, to determine a timing period for energization of the solenoid valve in the shift-up operation in accordance with the drive torque of the vehicle engine, to maintain the solenoid valve in its deenergized condition during the timing period, and to energize the solenoid valve upon lapse of the timing period.

Control apparatus for automatic transmission

During a shift operation, a time interval TT which is required to switch a mechanical gear ratio is detected. To bring it into coincidence with a reference value, the duty cycle with which a linear solenoid valve SL6 which determines a back pressure on an accumulator is energized is adjusted. The duty cycle is adjusted in accordance with an oil temperature, a throttle valve opening and a shift mode of an automatic transmission in order to prevent the occurrence of shift shocks as a result of a variation in the shift response of the automatic transmission from transmission to transmission or with time.

Hydraulic control system with condition responsive accumulator control

A shift control apparatus for an automatic transmission includes a kickdown orifice control valve for changing over two systems of hydraulic-pressure supply lines which supply hydraulic pressure to friction engaging elements on an engaging side via at least one orifice by sliding a spool between a first position at which the spool is urged by a spring and a second position at which the spool is urged by changeover hydraulic pressure acting in a direction opposite the spring, a solenoid valve mounted at a point along a line which introduces the changeover hydraulic pressure, and control means for controlling opening and closing of the solenoid valve, e.g., by duty-control or timer. Duty control is made according to vehicle velocity and throttle opening and corrected according to the engine rotational state.

Shift control apparatus for automatic transmissions

Hydraulic control system for automatic transmission

An apparatus and method for synchronizing shifting of a main transmission and a subtransmission, particularly in automatic transmissions having more than four speed ranges. Synchronism is achieved by initiating the shifting of the main transmission when the speeds of the input and output shafts of the main transmission achieve a predetermined relationship.

For a 2.fwdarw.1 shift, a timing solenoid valve SL5 is maintained at a duty cycle of 0% (off) for an interval TE=1.5 sec from the initiation of the shift operation and then the duty cycle is changed to 100% (on) after the TE interval so that an oil pressure of a brake B.sub.2 is maintained low during the shift operation while the oil pressure is increased to a high oil pressure for transfer of a maximum torque used in the first speed range upon completion of the shift operation. In response to a switching of a shift lever from D or S range to L range, the timing solenoid valve SL5 is energized with a duty cycle of 100% (on) at 2 sec after such switching to provide a high oil pressure for transfer of the maximum torque, thus preventing a shift shock from occurring as a result of a switching from D or S to L range. Since a control over the oil pressure through the timing solenoid valve SL5 during the shift operation takes place by switching an energization level of the solenoid SL5, the oil pressure can be switched in an accurate manner.

A shift control device for an automatic transmission comprises a shift valve, a solenoid valve connected to the shift valve, a shift timing valve also connected to the shift valve, a cut-off device connected to the solenoid valve and the shift timing valve, and a timing solenoid valve connected to the cut-off device so as to avoid the problem of shift shock which occurs when the timing solenoid valve is in an abnormal operating condition.

Shift control device for an automatic transmission

An automatic transmission shift control device has multiple friction engaging elements, and a shift timing valve port, a port for an underlap operating control-mode. A timing solenoid valve, a throttle sensor, an automobile speed sensor, and a controller operate the timing solenoid valve by signals from the throttle sensor and the automobile speed sensor. A shift map having an overlap area and an underlap area determines position of the shift timing valve within those areas. The shift timing valve being changed independent of the position in the areas determined by the degree of throttle opening and the automobile speed.

Growing community of inventors

Nagoya, Japan

Masato Shimei