Jatco Corporation

Nissan Motor Company Limited

Jatco Transtechnology Ltd.

Jacto Ltd

Tatsuya Imamura

Osamu Sato

Kazuhiro Takatori

Hiroshi Sekiya

Yasushi Fujita

Koji Dohi

Toshiji Iida

Kazuhito Sano

Kouji Saitou

Kazuo Tomioka

Satoshi Segawa

Toshihide Fukasawa

Morimasa Yamawaki

Nobuo Kurogo

Kazutaka Adachi

Masayoshi Nakasaki

Aki Hayakawa

Masayuki Kobayashi

A control device of a lock-up clutch of a torque converter interposed between a transmission and engine used with a vehicle, is disclosed. The control device has a sensor which detects an input rotation speed to the torque converter, a sensor which detects an output rotation speed from the torque converter, a differential pressure control device which controls the differential pressure applied to the lock-up clutch, and a controller which sets a target slip rotation speed of the torque converter; calculates a real slip rotation speed which is a difference between the detected input rotation speed and the detected output rotation speed; and performs feedback control to determine the differential pressure applied to the lock-up clutch so that the real slip rotation speed coincides with the target slip rotation speed. The controller is programmed to: set the target slip rotation speed to a first target slip rotation speed determined from a vehicle running parameter; perform feedback control so that the real slip rotation speed coincides with the first target slip rotation speed; change over the first target slip rotation speed to a second target slip rotation speed according to an error between the first target slip rotation speed and the real slip rotation speed; after changing over, and perform feedback control so that the real slip rotation speed coincides with the second target slip rotation speed; wherein the first and second target slip rotation speeds are different functions of time.

Control of lock-up clutch

A lock-up clutch control apparatus for controlling a lock-up clutch () provided in a torque converter () installed between an engine () and a transmission (), is disclosed. The lock-up clutch control apparatus has a differential pressure generator () which engages, causes a slip of or disengages the lock-up clutch by adjusting the differential pressure supplied to the lock-up clutch (); a sensor () for detecting a rotational speed of the engine; a sensor () for detecting an input rotational speed to the transmission; and a controller (). The controller () conducts proportional integration control by using a command signal to the differential pressure generator (), so that an actual slip rotational speed, which is the difference between the engine rotational speed (Np) and input rotational speed (Ni) to the transmission, becomes a target slip rotational speed (Nt). The controller is programmed to conduct integration accumulating the difference (&#x394;N) between the target slip rotational speed (Nt) and the actual slip rotational speed (SN); to determine whether the accumulated integrated value (I) is equal to or higher than a predetermined integration value (It); and to stop the integration when the accumulated integration value (I) is equal to or higher than the predetermined integration value (It).

Lock-up clutch control

A lock-up clutch control device which controls a lock-up clutch provided in a torque converter installed between an engine and a transmission, is disclosed. The lock-up clutch control device changes over between a converter state and a lock-up state of the torque converter according to a differential pressure command value (LUprs) relating to a differential pressure supplied to the lock-up clutch. The lock-up clutch control device includes a differential pressure generating device () which generates the differential pressure supplied to the lock-up clutch; input torque detection means () which detects an input torque (Te) to the torque converter; and a controller (). The controller () is programmed to compute a real differential pressure (P_lu) based on the detected input torque (Te) upon completion of the engagement of the lock-up clutch; compute a learning value (P_learn(Tai)) relating to a differential pressure deviation, based on the difference between the computed real differential pressure (P_lu) and differential pressure command value (P_ref) upon completion of the engagement of the lock-up clutch, and store the learning value (P_learn(Tai)); correct a present differential pressure command value (LUprs_slp) based on the learning value (P_learn(Tai)); and send the corrected differential pressure command value (LUprs) to the differential pressure generating device ().

Lock-up control for torque converter

A lock-up clutch control device which controls a lock-up clutch () provided in a torque converter () interposed between an engine () and a transmission () used with a vehicle, is disclosed. The lock-up clutch control device has a differential pressure generating device (), a vehicle speed sensor (), a throttle valve opening sensor (), an transmission input shaft rotation speed sensor (), engine torque detection means (), and a controller (). The controller () determines, based on the detected vehicle speed (VSP) and the detected throttle valve opening (TVO), whether or not a control region of a torque converter is a converter region wherein control is performed to disengage the lock-up clutch. When the control region of the torque converter is not the converter region, the controller () determines whether or not the control region of the torque converter is a slip control region wherein control is performed to make the lock-up clutch slip, based on the detected input shaft rotation speed (Npri) of the transmission and the detected engine torque (Te). When the control region of the torque converter is the slip control region, the controller commands the differential pressure generating device () to cause a slip of the lock-up clutch ().

A lock-up clutch control device controls a lock-up clutch provided in a torque converter in a vehicle. The lock-up clutch control device includes a sensor for detecting a rise of a vehicle speed; a differential pressure generator which generates a differential pressure to lock the lock-up clutch; and a controller. The controller is programmed to command the differential pressure generator to lock the lock-up clutch when the vehicle speed exceeds a predetermined low vehicle speed, after the vehicle is started; subsequently monitor the rise of the vehicle speed; and command the differential pressure generator to unlock the lock-up clutch when the monitored rise of the vehicle speed is lower than a preset value.

A lock-up clutch control device controls a lock-up clutch provided in a torque converter mounted between an engine and a transmission of a vehicle. The lock-up clutch control device switches between a converter state and a lock-up state by controlling a differential pressure supplied to the lock-up clutch. The lock-up clutch control device has a controller and a differential pressure generator for generating the differential pressure in response to a differential pressure command value. The controller calculates a first differential pressure command value which decreases at a predetermined rate, after the vehicle speed becomes a first predetermined speed; sets the differential pressure command value to a second differential pressure command value, before the vehicle speed becomes a second predetermined speed; and sets the differential pressure command value to a value at which the lock-up clutch is immediately released, when the vehicle speed becomes the second predetermined speed.

A lock-up clutch control device, which controls a lock-up clutch () installed in a torque converter () interposed between an engine () and a transmission () used with a vehicle, is disclosed. The lock-up clutch control device has a differential pressure generating device () which engages or disengages the lock-up clutch by adjusting a differential pressure supplied to the lock-up clutch, a sensor () which detects a vehicle speed, and a controller. The controller is programmed to: determine whether or not the vehicle speed is equal to or larger than a first threshold value (V) corresponding to a lock-up ON vehicle speed; command the differential pressure generating device to engage the lock-up clutch, when the vehicle speed is equal to or larger than the first threshold value (V); determine whether or not the vehicle speed has reached a second threshold value (V) larger than the first threshold value (V); set a lock-up OFF threshold value (V/V) which depends on whether the vehicle speed has reached the second threshold value (V); and command the differential pressure generating device to disengage the lock-up clutch, when the vehicle speed is equal to or less than the lock-up OFF threshold value.

In lock-up capacity control apparatus and method for a torque converter, the torque converter is caused to have a converter state in which a relative revolution between input and output elements of the torque converter is free of limitation in a case where a lock-up capacity (L/Uprso) during a no-load state is equal to or larger than a shock determining lock-up capacity (&#x3b1;), during an acceleration slip lock up in which the lock-up capacity of the torque converter is augmented by means of a time series control which accords with a load state of an engine, and the torque converter is caused to be oriented toward a lock-up state in which the relative revolution is zeroed by continuing an augmentation of the lock-up capacity by means of the time series control in a case where the lock-up capacity during the no-load state is smaller than the shock determining lock-up capacity.

Lock-up capacity control apparatus and method for torque converter

A controller () performs open loop control of the engaging state of a lockup clutch () through a switching mechanism () when a torque converter () transitions from a first state in which the lockup clutch () is disengaged to a second state in which the lockup clutch () is at least partially engaged. At this time, the controller () estimates the engine torque at the time when open loop control ends, estimates a necessary lockup capacity required for the converter () at the time when open loop control ends, based on the estimated engine torque, and controls the engaging state of the lockup clutch () through the switching mechanism () to make the lockup capacity at the time when open loop control ends become the necessary lockup capacity.

Power transmission device having a torque converter with a lockup clutch and lockup control method for torque converter

A lock-up control device for a lock-up torque converter of an automatic transmission is provided which starts measuring an elapsed time when the throttle opening exceeds a first predetermined value due to depression of an accelerator pedal during lock-up clutch slip control. When the throttle opening exceeds a second predetermined value due to sudden depression of the accelerator pedal prior to the elapse of a determination time, a transmission controller terminates the lock-up clutch slip control. After a rapid increase, the slip amount starts decreasing upon termination of the lock-up clutch slip control. Therefore, the temperature of a facing stops rising when the lock-up clutch slip control is terminated, and this improves the durability of the facing. The lock-up clutch slip control is re-started when the throttle opening is reduced to a predetermined value, and this maintains the excellent fuel economy performance.

Lock-up control device for torque converter of automatic transmission

A pressure regulating valve regulates an original pressure outputted from a manual valve by means of a control pressure generated by a solenoid in a D range and supplies the regulated original pressure to an engaging element. An electronic control unit filters a current signal supplied to the solenoid to generate the control pressure by using a strong filter when a N range is switched to a D range during stoppage of a vehicle so that the control pressure has a gentle rise characteristic, switches the filtering process to a filtering process using a weak filter to rapidly move the pressure regulating valve in a working pressure discharge direction when the N range is switched to the D range during running of the vehicle and returns the filtering process to the filtering process using a strong filter after a predetermined time period. Thereby, occurrence of shock is suppressed when the D range is again selected after the N range is selected during running in the D range.

Control system for automatic transmission

A shift control system for an automatic transmission having an automatic shift mode in which a proper gear ratio is automatically selected according to a shift command based on a throttle valve opening and a vehicle speed, and further having a manual shift mode in which a gear ratio is selected according to a shift command given by driver's manual operation. The shift control system includes timer means for counting an elapsed time after a shift operation has been started. The elapsed time is compared with a predetermined first re-shift permission time in the case of automatic shift operation and with a predetermined second re-shift permission time in the case of manual shift operation. The first re-shift permission time and the second re-shift permission time are different from each other to optimize the shift control both in the automatic shift mode and in the manual shift mode.

Shift control system for automatic transmission

An automatic transmission has a gear transmission mechanism with engaging devices. Up-shifting is achieved with oil pressure, which is controlled with an open control component, a gradient of which is determined based on input torque, and a feedback control component, which is based on a target gear ratio. To prevent shock during an up-shift caused by releasing the accelerator, the feedback control component is set to zero when the amount of change in the throttle opening is equal to or greater than a predetermined threshold value. As a result of inhibiting increase in feedback to make up for a tendency for oil pressure depending on an open control component to decrease as a result of the throttle opening reducing and input torque falling, increase of the oil pressure command value becomes smooth. Peaks of the output torque are therefore suppressed.

A hydraulic control system controls a hydraulic pressure as a standby pressure in a period from an engagement start point at which an engagement instruction for engaging a friction element is started to an abutment start point at which an abutment between an input element and an output element is started. The hydraulic pressure supplied to at least one friction element is so increased as to switch the friction element from a disengagement state to an engagement state, thus transmitting a revolution of the input element of the friction element to the output element of the friction element. The hydraulic control system includes: a speed sensor for sensing a speed of the friction element; and a standby pressure increase section for increasing the standby pressure in accordance with the speed of the friction element sensed with the speed sensor.

Hydraulic control system for automatic transmission, and method of controlling hydraulic pressure

When a transmission selector lever is operated from P or N range to D range, an input clutch to be engaged at the fifth gear position is temporally engaged to reduce shift shock when the engaging element for the first gear position is engaged. An oil pressure command value for actuating the input clutch is increased with a constant inclination from a start point oil pressure value, and the start point oil pressure value is lowered when the engine speed is low or when an oil temperature is high. Even if a timing of completion of filling of working fluid to the input clutch is fluctuated, the difference between the actual oil pressure and the oil pressure command value is suppressed to a small level and the occurrence of shock due to surge at the time of the filling completion is prevented.

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Fuji, Japan

Tatsuya Imamura