Aisin Seiki Kabushiki Kaisha

Aisin Seiki K.k.

Nobuyuki Isono

Yoshitami Saitou

Nobuyasu Suzumura

Masato Shimei

Shigeki Goto

Tetsuhiro Miyazawa

Makoto Inoue

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

An electronically controlled automatic transmission system for applying and releasing clutches and brakes when the gears for the speed ranges are to be shifted or changed in accordance with the drive torque of the engine. Each brake and clutch is controlled by a solenoid valve and a manual valve. The manual valves control the application of fluid pressure to the clutches and the brakes. Each manual valve has a separate solenoid valve which controls the manual valve in accordance with the detected value of the driving force of the engine. In addition, the automatic transmission system measures the number of revolutions of the input shaft to the automatic transmission after the clutches and brakes at the release side are released for a gear shift, and detects the acceleration of the number of revolutions of the input shaft of the automatic transmission.

Automatic transmission system which minimizes shift-shock using duty

Hydraulic control system for automatic transmission

The rotational speed of an engine Ne and a drum rotational speed Nt of a clutch Cl are compared against each other to determine a power on/off. For a 2.fwdarw.3 and a 2.fwdarw.4 shift in the power off condition, a timing solenoid SL5 is turned on (duty cycle of 100%) to accelerate the termination of a preceding speed range, thus increasing a time delay between such termination and the activation of a new speed range to be established. For other shifts, a time difference between the termination of a preceding speed range and the activation of a new speed range to be established is adjusted, by energizing the solenoid SL5 in accordance with the throttle opening .theta. and the vehicle speed No such that SL5 is energized with a high duty cycle for a longer .theta. and with a low duty cycle for a smaller .theta..

In a four wheel drive vehicle having an anti-lock brake system in combination with a front differential gear, a rear differential gear and a center differential gear, a center differential lock mechanism between the front differential gear and the center differential gear is automatically disengaged when a throttle opening sensor detects a low degree of throttle opening independently of the vehicle speed. The device for automatically disengaging the center differential lock mechanism is operated under the control of an operating unit receiving input signals from a center differential gear operating switch, a vehicle speed sensor, a rear wheel speed sensor, a brake lamp sensor and a throttle opening sensor.

Center differential lock mechanism controlling device

An electronically controlled automatic transmission system including an automatic transmission having a plurality of clutches and brakes activated by application of a fluid pressure to change the gear ratio by engagement and disengagement of the clutches and brakes, a fluid pressure switching device for controlling the application of the fluid pressure to the clutches and brakes, and an electronic controller for changing the engagement and disengagement of the clutches and brakes by driving the fluid pressure switching device in accordance with the running condition of the vehicle, the electronic controller also controlling the speed of engagement of a clutch or brake which is to be engaged. The electronic controller includes a torque sensor for detecting the torque of the output shaft of the automatic transmission, and an engagement speed correcting device for correcting the speed of engagement of a clutch or brake which is to be engaged on the basis of the detected torque. If the condition of double engagement is judged to be improper in the process of gear-shifting, the speed of engagement of the clutch or brake to be engaged is automatically corrected so that the condition of double engagement is shifted to an optimal one by feedback control. Thus, the shock applied to the vehicle during a gear-shifting operation is reduced.

Electronically controlled clutch engagement speed correcting for an

In a vehicle having a torque converter and a lock-up clutch for effecting engagement and disengagement between input and output shafts of the torque converter, an engine brake controlling apparatus provides engine brake control independently of vehicle speed and includes a device for detecting the number of revolutions of the input shaft of the torque converter; a device for detecting the number of revolutions of the output shaft of the torque converter; and a control device for allowing the lock-up clutch to be engaged when the number of revolutions of the output shaft has exceeded the number of revolutions of the input shaft and for releasing the lock-up clutch when brake operation is detected.

Engine brake controlling apparatus using a lock-up system

An electronically controlled automatic transmission including an automatic gear shift for changing the gear ratio according to the coupling/decoupling of the brake and clutch, a hydraulic switch for controlling a hydraulic pressure exerted on the brake and clutch, a timer for setting a time of coupling/decoupling of the clutch and brake during a shifting period, a detector for detecting vehicle information, a time correcting device for correcting the set time according to the detected vehicle information, and an electronic control device for driving the hydraulic switch and for changing the state of coupling/decoupling. The electronic control device having a temperature detector for detecting the temperature of the working fluid of the hydraulic switch, and a feedback stop device for stopping the correction by the time correcting device when the temperature detector detects that the temperature of the working fluid is below a predetermined temperature.

Electronically controlled automatic transmission

A controlling device for an automatic speed change mechanism is capable of preventing a sudden acceleration of an automobile against the intention of the driver. The device includes a shift position detector for emitting electric signals indicating the selection state of a manual shift device; a braking detector for emitting electric signals corresponding to the actuation/non-actuation of a braking device; and an electronic controlling device which monitors the electric signals emitted by said shift position detector and said braking detector, controls the said shifting device corresponding to the selection state of a manual shifting device to switch over the connection mode of the speed change mechanism, and during the non-actuation of the braking device, if the manual shifting device commands a switch-over from the non-connection mode to a connection mode, establishes a connection mode having a relatively small reduction ratio compared with the case of brake actuation.

Controlling device for automatic speed change mechanism

A control system for an automatic variable speed transmission accesses reference data for a down/up shift operation stored in a memory as a function of a particular speed range and a throttle opening. The data read from the memory is compared against a prevailing vehicle speed to determine the need for a down/up shift operation. The reference data includes a first set which is used for determining the need for a down/up shift operation, and a second set which is used in determining the need for a down shift operation when a rapid braking action is applied. When a brake pedal is depressed and the deceleration of the vehicle exceeds a given value, the need for a down operation is determined only utilizing the second set until the brake pedal is released, thus allowing the transmission to shift down to a lower speed range at a relatively higher vehicle speed.

Growing community of inventors

Aichi, Japan

Nobuyuki Isono