Jatco Corporation

Nissan Motor Company Limited

Takashi Eguchi

Seiichiro Takahashi

Hiroyasu Tanaka

Ryousuke Nonomura

Tomohiro Utagawa

Mamiko Inoue

Hisao Nobu

Masato Mori

Kenji Sakakibara

Masahide Ito

Takahiro Ikeda

Masayuki Shimizu

Tomoyuki Mizuochi

Takahiro Kobayashi

Tetsuya Izumi

Akito Suzuki

Toshiji Iida

Miki Kinoshita

Yusuke Kimura

Takuichiro Inoue

Yoshinobu Kawamoto

Tomoaki Honma

Hironori Miyaishi

Junsuke Ino

Hidemasa Kawaguchi

Yoshio Yasui

Rei Koike

Keita Okudaira

Yohei Shimokawa

Masami Sakai

Yuta Ishinabe

Toshiaki Izawa

Kazuki Ishida

Tesuya Asada

A first target secondary pulley pressure Psteng is calculated based on an output torque Teng of an engine, and then an offset value Psteng+PO is calculated by adding a predetermined offset PO to the first target secondary pulley pressure Psteng. The first target secondary pulley pressure Psteng is outputted as a target secondary pulley pressure Ps(n) when a target secondary pulley pressure Ps(n&#x2212;1) in a previous control cycle is less than or equal to the first target secondary pulley pressure Psteng; the offset value Psteng+PO is outputted as the target secondary pulley pressure Ps(n) when the target secondary pulley pressure Ps(n&#x2212;1) in the previous control cycle is greater than or equal to the offset value Psteng+PO; and otherwise, the target secondary pulley pressure Ps(n&#x2212;1) in the previous control cycle is outputted as the target secondary pulley pressure Ps(n), thereby suppressing an oscillation in the target secondary pulley pressure Ps(n).

Controller for continuously variable transmission

A CVTECU includes a secondary-pressure control section and a line-pressure control section that performs a same-pressure control to equalize a line pressure and a secondary pressure with each other if a predetermined start condition is satisfied. The line-pressure control section realizes a same-pressure state between the line pressure and the secondary pressure by lowering the line pressure below a target secondary pressure, and then controls the line pressure such that an actual secondary pressure is brought to the target secondary pressure by hydraulic feedback control while maintaining the same-pressure state. The secondary-pressure control section includes a restriction section that restricts an accumulation of integral term of an integral action for a duration between a time point at which the actual secondary pressure starts to be pushed down and a time point at which the same-pressure state between the line pressure and the secondary pressure is realized.

Control device for continuously variable transmission

A control apparatus for a continuously variable transmission with a sub transmission includes a primary solenoid valve installed at an oil passage in a midway position between a mechanical oil pump and a primary pulley and configured to control a hydraulic pressure to be supplied to the primary pulley. The control apparatus further includes a transmission controller which outputs a primary current command value to a primary solenoid valve. The transmission controller outputs the primary current command value which previously closed the oil passage between the mechanical oil pump and the primary pulley to the primary solenoid valve before a rise in an engine revolution number due to at least a re-start of the engine, when a coast stop control/an idle stop control is carried out.

A transmission controller searches a mechanical High, which is a minimum value of a possible speed ratio of the continuously variable transmission (CVT), based on an actual speed ratio, sets a control High lower than the mechanical High by a predetermined amount, and controls a speed ratio of the CVT by setting a minimum value of a speed ratio range of the CVT at the control High.

Continuously variable transmission and control method therefor

In a hydraulic control circuit including a solenoid valve, whose change responsiveness in an actual pressure with respect to a change in an instructional pressure deteriorates when the instructional pressure enters a dead band region on a lower pressure side than a dead band threshold, for adjusting a hydraulic pressure supplied to a hydraulic device operated by the hydraulic pressure based on the instructional pressure, the instructional pressure is increased in a stepwise manner to a charge pressure higher than the dead band threshold, when the instructional pressure is set in the dead band region and the instructional pressure increases within the dead band region to such an extent that a speed ratio does not change. Then, a lower limit of the instructional pressure is set to the dead band threshold, and use of the dead band region is prohibited for a certain period of time.

Hydraulic control circuit and its control method

A transmission controller determines whether a shift is a kickdown, and when the shift is determined as the kickdown, the target line pressure is increased to a first target pressure corresponding to an input torque to a continuously variable transmission increased by the kickdown; the transmission controller then determines whether the line pressure has reached the first target pressure, and if determined that the line pressure has reached the first target pressure, the target line pressure is increased to a second target pressure higher than the first target pressure.

Continuously variable transmission and a hydraulic control method thereof

A target primary pressure and a target secondary pressure are set based on a speed ratio, a target line pressure as a target value of a line pressure is set to be a value obtained by adding an offset amount, as a positive value, to either one having a higher value out of the target primary pressure and the target secondary pressure, in at least a cross-point region as a region where an absolute value of a deviation, obtained by subtracting the target primary pressure from the target secondary pressure, is smaller than a predetermined deviation, and a primary pressure, a secondary pressure, and the line pressure are controlled to be the target primary pressure, the target secondary pressure, and the target line pressure, respectively.

Continuously variable transmission and its hydraulic pressure control method

A transmission controller determines whether a shift returning to low, changing a speed ratio of a continuously variable transmission to the lowest when a vehicle decelerates, is being performed or not, calculates a primary pressure measured lower limit value at which a belt begins to slip actually, based on a deceleration of the vehicle and the speed ratio of the continuously variable transmission, and sets a lower limit value of a target value of the primary pressure during the shift returning to low as the primary pressure measured lower limit value.

A transmission controller detects a rotation speed of an input shaft, calculates an inertia torque input to a continuously variable transmission based on a change ratio of the detected rotation speed, obtains a positive inertia torque by extracting a positive portion from the calculated inertia torque, and corrects pulley pressures based on the extracted positive inertia torque.

Continuously variable transmission and hydraulic pressure control method therefor

The shift control unit shifts the sub-transmission mechanism while changing the speed ratio of the variator in response to a change in the speed ratio of the sub-transmission mechanism so that the through speed ratio does not change after the through speed ratio is caused to reach the final through speed ratio by changing only the speed ratio of the variator if the speed ratio corresponding to the shift instruction from the driver is between a first speed ratio at which the sub-transmission mechanism is in the second gear position at the high speed side and the speed ratio of the variator is lowest and a second speed ratio at which the sub-transmission mechanism is in the first gear position at the low speed side and the speed ratio of the variator is highest when the manual mode is selected.

Continuously variable transmission and shift control method

A control apparatus for a vehicle equipped with continuously-variable transmission includes a drive source; a continuously-variable transmitting mechanism including a primary pulley, a secondary pulley and a power transferring member; a friction engagement element provided between the drive source and the continuously-variable transmitting mechanism; and a vehicle-stop LOW shift control section including a vehicle-stop judging section configured to judge if the vehicle is in a stopped state. A power-transferring state of the friction engagement element is controlled by an engaging-force control. The vehicle-stop LOW shift control section starts a vehicle-stop LOW shift control to shift a pulley ratio of the continuously-variable transmitting mechanism toward LOW side when the vehicle-stop judging section determines that the vehicle is stopped under a power-transferring state where the friction engagement element is in an engaged state and the pulley ratio is not in a LOWEST region.

Control apparatus for vehicle equipped with continuously variable transmission

In a manual mode, a gear position of a continuously variable transmission is selected based on an input operation from a driver, a final through speed ratio is set based on the selected gear position and a variator and a sub-transmission mechanism are controlled to realize the final through speed ratio. Whether an input torque to the sub-transmission mechanism is positive or negative is determined based on an input torque to the sub-transmission mechanism when the manual mode is selected.

Continuously variable transmission and power on/off determination method

The shift control unit executes a control to cause the through speed ratio to follow the final through speed ratio by changing only the speed ratio of the variator if a shift instruction is given from the driver a plurality of times in a row when the manual mode is selected, and advances the start of a change in the speed ratio of the sub-transmission mechanism or accelerates the progression of the change of the speed ratio as compared with the case where the manual mode is not selected when the speed ratio of the variator is maximized or minimized and the through speed ratio cannot follow the final through speed ratio.

A transmission control unit reduces a hydraulic pressure of a release-side frictional engagement element which is to be released of a sub-transmission mechanism and reduces this reduction amount as an input torque to the sub-transmission mechanism increases at the time of starting a shift when a manual mode is selected, the input torque is positive and the sub-transmission mechanism is to be shifted down.

Continuously variable transmission and control method therefore

Continuously variable transmission includes: a variator; a stepwise auxiliary transmission mechanism; and a shift controller configured to set a desired through transmission ratio based on the calculated desired target rotational speed, the shift control section including; a slope road upshift prohibiting section configured to prohibit upshift of the auxiliary transmission mechanism when the vehicle runs on a slope road, and a slope road upshift section configured to upshift the auxiliary transmission mechanism when the vehicle runs in a predetermined running state when the slope road upshift prohibiting section prohibits upshift of the auxiliary transmission mechanism, and to perform the shift of the auxiliary transmission mechanism while the transmission ratio of the variator is varied in accordance with the variation of the transmission ratio of the auxiliary transmission mechanism to prevent varying the through transmission ratio even when the vehicle runs on the slope road.

Growing community of inventors

Machida, Japan

Takashi Eguchi