Nissan Motor Company Limited

Satoshi Sakakibara

Akihiro Ueki

Tatsuo Wakahara

Chiaki Harada

Hiromasa Sakai

Yasuhiro Yamauchi

Kenichiro Murakami

Kazuhiro Takatori

Takashi Nakazawa

Ryozo Hiraku

Toru Urasawa

Yutaka Fujisawa

Asuka Soutome

Makoto Shouji

An automatic transmission system for a vehicle includes a shift-by-wire system which converts a selected command operation range of a range selector into an electric signal and which changes an actual operation range of an automatic transmission into the selected command operation range by driving an actuator according to the electric signal. A lock mechanism restricts the operation of the range selector when the shift-by-wire system is electrically turned off regardless of the present operation range of the range selector.

Automatic transmission system for vehicle

A hybrid vehicle includes a first motor generator ( ) and an engine ( ) connected to first drive wheels ( ) via a transmission ( ), a second motor generator connected to a second drive wheel ( ), a battery ( ) electrically connected to the first and second motor generators ( ), a sensor ( ) which detects a running state of the vehicle, a sensor which detects a charge state of the battery ( ), and a controller ( ). The controller ( ) controls a drive force of the engine ( ) and the first motor generator ( ) according to the running state of the vehicle and the charge state of the battery ( ), and drives the second motor generator ( ) by the battery ( ) or the power generated by the first motor generator ( ).

Four-wheel drive hybrid vehicle

A lock-up controller is provided for shifting a torque converter of a vehicle from the lock-up state to the unlock state when the accelerator pedal is depressed at a speed larger than a predetermined speed when the vehicle is coasting. The controller is further functioning to prevent the torque converter from shifting to the lock-up state when the torque converter has been shifted to the unlock state and the vehicle speed is within the predetermined re-lock-up prevention speed range so as to avoid frequent lock-up/unlock operation of the torque converter.

Lock-up control device for a torque converter

A hybrid vehicle is driven by either an engine or a motor by tightening or releasing a clutch interposed between an engine and a transmission. A generator is connected to the engine, and the engine torque is absorbed by the generator when the power source is changed over from the motor to the engine. The clutch is tightened when the engine rotation speed of the motor and the engine coincide. As a result, the torque input to the transmission is maintained constant, and a shock due to change-over of the power source is suppressed.

Hybrid vehicle

A lock-up controller is provided for shifting a torque converter of a vehicle from the lock-up state to the unlock state when the accelerator pedal is depressed at a speed larger than a predetermined speed when the vehicle is coasting, The controller is further functioning to prevent the torque converter from shifting to the lock-up state when the torque converter has been shifted to the unlock state and the vehicle speed is within the predetermined re-lock-up prevention speed range so as to avoid frequent lock-up/unlock operation of the torque converter.

Lock-up hystersis control device for a torque converter

A lockup control system controls a lockup state of the automatic transmission employing a torque converter with a lockup clutch. The lockup control system executes a lockup clutch engagement pressure control for decreasing an engagement differential pressure of the lockup clutch at a predetermined differential pressure for a predetermined time period under a coast lockup state. Further, the lockup control system executes a learning control for obtaining the predetermined differential pressure by adding a differential pressure correction value to a differential pressure learning value by which the torque converter generates a slight slip under the coast lockup state. Therefore, even during the coast lockup state, both of suppressing vibrations by a lowering of a lockup capacity and maintaining a responsibility for re-increasing the differential pressure are ensured.

Lockup control system for automatic transmission

A motor vehicle includes an internal combustion engine and an automatic transmission powered by the engine. The engine has a throttle valve for controlling the amount of air fed thereto. The transmission selectively assumes an Over-drive possible D-range wherein both a lock-up ON condition and a lock-up OFF condition are available and an Over-drive impossible D-range wherein only the lock-up OFF condition is kept. A control system comprises a first section for detecting a first condition of the engine wherein an open degree of the throttle valve is reduced to a certain degree; a second section for detecting a second condition of the transmission wherein the lock-up ON condition of the Over-drive possible D-range is kept; and a third section for engaging a friction element of the transmission to induce an engine brake when the first and second sections detect the first and second conditions respectively.

Control system of automotive automatic transmission

An engine-transmission drivetrain includes a torque converter situated between the engine output shaft and the transmission. The torque converter includes a lock-up clutch. A speed sensor, which measures the rotational speed of an output shaft of the transmission, generates a pulse signal. A transmission controller includes a deceleration dependent lock-up release command generator and a torque converter speed dependent lock-up release command generator. The pulse signal from the speed sensor is used as inputs to both of the lock-up release generators. In the deceleration dependent lock-up release command generator, the pulse signal is processed to derive information as to the magnitude of deceleration which the transmission output shaft is subject to. In the torque converter speed dependent lock-up release generator, the pulse signal is processed to derive information as to rotational speed of an output element of the torque converter. At deceleration with the magnitude of deceleration greater than or equal to a predetermined reference, the deceleration dependent lock-up release generator gains authority over the lock-up release control. At deceleration with the magnitude of deceleration less than the predetermined reference, the torque converter speed dependent lock-up release generator gains authority over the lock-up release control.

Lock-up control system for vehicle drivetrain with torque converter

A fuel cut-off and fuel-supply recovery control system for an internal combustion engine coupled to an automatic power transmission with a lock-up torque converter having a lock-up device operable at either one of an open converter state and a locked-up state through a lock-up control based on engine and vehicle operating conditions, comprises an electronic control module configured to store a fuel-cut engine speed (N.sub.1, N.sub.3) above which a fuel cut-off control is executed under a specified engine and vehicle operating condition and a fuel-supply recovery engine speed (N.sub.2) below which a fuel-supply recovery control is restarted so that fuel supply to the engine is recovered from the fuel cut-off control. The electronic control module variably determines a hysteresis between the fuel-cut engine speed and the fuel-supply recovery engine speed so that a deviation (N.sub.3 -N.sub.2) of the fuel-cut engine speed from the fuel-supply recovery engine speed in the locked-up state is smaller than a deviation (N.sub.1 -N.sub.2) of the fuel-cut engine speed from the fuel-supply recovery engine speed in the open converter state.

Fuel cut-off and fuel-supply recovery control system for internal

An automatic power transmission of an automotive vehicle includes various frictional elements and frictional brakes and can prevent a shift shock from occurring by increasing a working hydraulic pressure applied to a certain frictional element (forward clutch F/C) so as to make fast a reengagement of the certain frictional element when a down-shifting from a high gear speed range to a low gear speed range occurs. In a preferred embodiment, the working hydraulic pressure present during the down-shifting is introduced into an accumulator so as to disable a stroke of the accumulator. In another preferred embodiment, a time at which a shifting solenoid (A) is turned from its ON state to its OFF state is retarded after a control valve control solenoid (C) is turned from its OFF state to its ON state in response to an instruction of a controller to shift down the gear speed range. In addition, a fuel consumption of the associated engine is improved by an extension of a lock-up interval off a torque converter.

Automatic power transmission of automotive vehicle

Under a higher speed gear position of the transmission, a control valve can drain a hydraulic pressure of a forward clutch to cause the forward clutch to take a disengaged condition. With this, undesired friction of a forward one-way clutch under such higher speed gear position is suppressed. A fail-safe system is employed for recovering an engaged condition of the forward clutch even when the control valve is stuck at such pressure draining position.

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Yamato, Japan

Satoshi Sakakibara