Jatco Corporation

Nissan Motor Company Limited

Ryousuke Nonomura

Mamiko Inoue

Seiichiro Takahashi

Hiroyasu Tanaka

Hideaki Suzuki

Takuichiro Inoue

Tatsuo Ochiai

Masaaki Uchida

Masato Koga

Tateki Jozaki

Ryoji Kadono

Jouji Seki

Takashi Eguchi

Masato Mori

Masahide Ito

Norio Asai

Makoto Sawada

Shinichiro Watanabe

Tomohiro Utagawa

Fumito Shinohara

Keita Okudaira

Takanori Aoki

Satoru Ishii

A transmission controller executes synchronization shift of shifting a variator in a direction opposite to a speed ratio change direction of a sub transmission mechanism when shifting a sub transmission mechanism. When a gear position of the sub transmission mechanism is at the second gear position and an output increase request of a power source is made, the transmission controller prohibits the synchronization shift and shifts only the sub transmission mechanism from a second gear position to a first gear position.

Continuously variable transmission and method of controlling the same

When a through speed ratio, which is an overall speed ratio of a variator and a subtransmission mechanism, varies from a larger speed ratio than a mode switch speed ratio to a smaller speed ratio than the mode switch speed ratio, a gear position of the subtransmission mechanism is changed from a first gear position to a second gear position. The mode switch speed ratio is set at a through speed ratio obtained when the speed ratio of the variator is a Highest speed ratio and the gear position of the subtransmission mechanism is the first gear position.

Continuously variable transmission and control method thereof

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

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

A transmission controller permits a 2-1 shift, in which a gear position of a subtransmission mechanism is changed from a second speed to a first speed, when an accelerator pedal has been depressed to or above a predetermined opening. The gear position of the subtransmission mechanism is changed from the second speed to the first speed when an actual through speed ratio passes a mode switch line from a High side to a Low side while the 2-1 shift is permitted in the subtransmission mechanism.

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

A control device for a vehicle continuously variable transmission comprises a shift control means for controlling either of or both the speed ratio at the continuously variable transmission mechanism and the gear position at the subtransmission mechanism so as to adjust an overall speed ratio to a final speed ratio and a torque capacity control means for controlling the torque capacity at a disengagement-side frictional engagement element in the subtransmission mechanism so as to sustain a torque capacity value substantially equal to zero in an inertia phase occurring during a process of adjusting the gear position at the subtransmission mechanism from the first gear position to the second gear position when a negative torque is input to the vehicle continuously variable transmission.

Control of and control method for vehicle continuously variable transmission

A control device for a vehicle continuously variable transmissionincludes: final speed ratio setting means for setting an overall speed ratio of the continuously variable transmission mechanismand the subtransmission mechanismto be reached on the basis of an operating condition of the vehicle as a final speed ratio; shift control means for controlling the continuously variable transmission mechanismand the subtransmission mechanismsuch that the overall speed ratio aligns with the final speed ratio at a predetermined transient response; stagnation determining means for determining whether or not a stagnation period in which the overall speed ratio stops varying will occur during an upshift; and reduction control means for shortening a time required to advance to an inertia phase from a start of a shift in the subtransmission mechanismfollowing a determination that the stagnation period will occur.

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.

A control apparatus for an automatic transmission includes a stepwise variable transmission mechanism; a power ON/OFF state judging section; and a shift control section configured to control the stepwise variable transmission mechanism to a target rotational speed by disengaging the first engagement portion and engaging the second engagement portion in accordance with a torque inputted to the stepwise variable transmission mechanism, the shift control section being configured to engage one of the first engagement portion and the second engagement portion which has a function to suppress a variation of an input rotational speed of the stepwise variable transmission mechanism which is generated by a switching of the power ON/OFF state when the power ON/OFF state is switched at the shift control of the stepwise variable transmission mechanism, and to disengage the other of the first engagement portion and the second engagement portion.

Control apparatus and method for automatic transmission

A speed ratio of a continuously variable transmission mechanismis increased when a speed ratio of a subtransmission mechanismconnected in series to the continuously variable transmission mechanismis switched from a first speed to a second speed. When an excess rotation speed Nb obtained by subtracting a target rotation speed from an engine rotation speed Ne exceeds a determination value Nrduring this shifting process, a rapid rotation increase in an internal combustion engineis prevented by reducing a shift speed of the continuously variable transmission mechanism(SA).

Shift control of continuously variable transmission

A control system of an automatic transmission including a stepwise variable transmission section and a continuously variable transmission section makes a speed change control of the continuously variable transmission section cooperate with a change of an input rotation speed of the stepwise variable transmission section and is configured to judge, during the shift change of the stepwise variable transmission section, whether a delivery of a torque from one of a plurality of disengaging side frictional elements to one of a plurality of engaging side frictional elements is completed, and to start the speed change control of the continuously variable transmission section upon judgment that the delivery of the torque is completed and that an inertial phase has started.

Control system of automatic transmission

An inertia torque input into the continuously variable speed change mechanism from the subtransmission mechanism is estimated during the shift in the subtransmission mechanism. During the shift in the subtransmission mechanism, a required oil pressure, which is an oil pressure required to maintain a contact frictional force between the respective pulleys and the wrapped member, is calculated on the basis of an input torque into the continuously variable speed change mechanism and the inertia torque.

The transmission controller changes the gear position of the subtransmission mechanism and varies the speed ratio of the variator in an opposite direction to a speed ratio variation direction of the subtransmission mechanism when the actual through speed ratio passes a predetermined mode switch line. When the improvement in the shift response of the continuously variable transmission is determined to be required and the actual through speed ratio passes the mode switch line from a Low side to the High side, the transmission controller increases a shift speed of the subtransmission mechanism compared with a normal coordinated shift.

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Kawasaki, Japan

Ryousuke Nonomura