Jatco Corporation

Nissan Motor Company Limited

Seiichiro Takahashi

Mamiko Inoue

Ryousuke Nonomura

Hiroyasu Tanaka

Takashi Eguchi

Hideaki Suzuki

Tatsuo Ochiai

Takuichiro Inoue

Masaaki Uchida

Masato Koga

Tateki Jozaki

Ryoji Kadono

Jouji Seki

Tomoaki Honma

Takahiro Kobayashi

Hisao Nobu

Tomohiro Utagawa

Yuta Suzuki

Masato Mori

Kenji Sakakibara

Masahide Ito

Hideshi Wakayama

Takahiro Ikeda

Masayuki Shimizu

Yuzuru Tohta

Keichi Tatewaki

Daisuke Matsumoto

Takashi Matsuda

Yasushi Yabe

Tomoyuki Mizuochi

Jonggap Kim

Akito Suzuki

Yoshio Yasui

Koutarou Tagami

Daisuke Aoki

Hiroyuki Suzuki

Masahiro Iriyama

Takeo Hiramatsu

Hiroki Iwasa

Tomoyuki Suzuki

Shinichiro Watanabe

Tetsuya Izumi

Hironori Miyaishi

Hiroshi Sekiya

Kousuke Waku

Masayuki Miyazono

Kosuke Abe

Tomoaki Kabe

Fumito Shinohara

Nobuhiko Morifuji

Shin Tsukamoto

Yuji Okamoto

Nobuhide Kato

Itaru Shinohara

Hidemasa Kawaguchi

Norio Asai

Hitoshi Goka

Masayuki Mannen

Takaaki Matsui

Yoshihiro Kono

Takashi Nobukawa

Sunghoon Woo

Susumu Saitou

Yasuyuki Hashimoto

Koichi Sugita

Juwan Kim

Yohei Shimokawa

Masami Sakai

Yuta Ishinabe

Yoshihiko Ota

Toshiaki Izawa

Disclosed is a control device for a continuously variable transmission () that has, as forward speed change stages, a first speed change stage () and a second speed change stage (). The control device comprises a coordinated speed change means () that carries out a coordinated speed changing in such a manner that when the speed change stage of an auxiliary transmission mechanism () is about to be changed, a speed change speed of the auxiliary transmission mechanism () is coordinated with a variator () and the variator () is controlled to carry out a speed change in a direction opposite to that of the auxiliary transmission mechanism () while carrying out the speed change operation of the auxiliary transmission mechanism (), and a torque control means () that carries out a torque regulating control during the coordinated speed changing under up-shifting by the coordinated speed change means, the torque regulating control being a control for effecting a torque-up operation to a driving source () after effecting a torque-down operation to the driving source and including a timing through which a starting time point of a drive force gap caused by the coordinated speed changing is advanced and a timing through which an ending time point of the drive force gap is delayed.

Control device for continuously variable transmission

CVT controller has rotation speed sensors detecting driving and driven wheel rotation speed; driving and driven wheel speed difference detection unit detecting wheel speed difference &#x394;vfr; and bad road judgment unit judging that road is bad road when &#x394;vfr is first value &#x394;vfr_br or greater. CVT controller further has first belt clamping force increase unit increasing belt clamping force in case where road is judged to be bad road, as compared with case where road is not judged to be bad road; vibration detection unit detecting vehicle speed vibration fvsp; and second belt clamping force increase unit increasing belt clamping force when &#x394;vfr is second value &#x394;vfr_psec or greater or when fvsp is third value fvsp_psec or greater in case where road is not judged to be bad road, as compared with case where &#x394;vfr is less than &#x394;vfr_psec and case where fvsp is less than fvsp_psec.

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

Control device for continuously variable transmission has continuously variable transmission mechanism (CVT) transmitting power with belt () wound around primary and secondary pulley (); torque convertor () having pump impeller (), turbine runner () and lock-up clutch (); and control unit () controlling lock-up clutch () to predetermined engagement state and controlling the CVT to predetermined transmission ratio, according to travelling condition. Control unit () is configured to, when shifting lock-up clutch () from disengagement to engagement state, control transmission ratio of CVT so that when rotation speed difference (&#x394;N) between engine speed (Ne) and turbine speed (Nt) that is rotation speed of turbine runner is predetermined rotation speed difference (&#x394;N) or less, turbine speed (Nt) approaches engine speed (Ne) more than turbine speed (Nt) of case where control of transmission ratio of CVT, which is set according to travelling condition during shift of lock-up clutch (), is continued.

A continuously variable transmission (), wherein pressure equalization control is performed to make line pressure (PL) equal to secondary pressure (Psec) when prescribed start conditions are satisfied. During pressure equalization control, a secondary pressure indicated value (Psec_co) is raised by a prescribed amount (S), then a line pressure indicated value (PL_co) is gradually decreased (S). If determination is made that line pressure is the same as the secondary pressure after secondary actual pressure (Psec) is lowered (S), then the line pressure is controlled so that the secondary actual pressure (Psec) becomes the secondary pressure indicated value (Psec_co) (S). At the start of pressure equalization control, if the difference (&#x394;Psec) found by subtracting the secondary pressure indicated value from the secondary actual value is negative (S), then a primary pressure indicated value is corrected on the basis of the difference (S).

Continuously variable transmission control device and control method

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.

A hydraulic control device controls hydraulic pressure supplied to a continuously variable transmission. The hydraulic control device includes a pressure regulating valve, a solenoid valve configured to control the pilot pressure, line pressure control means, and hydraulic control means. The pressure regulating valve includes an input port to which line pressure is input, an output port configured to supply an oil chamber of a second pulley with a second pulley pressure, a drain port configured to discharge the second pulley pressure from the oil chamber, and a spool moving according to pilot pressure to regulate the second pulley pressure. The line pressure control means is configured to control the line pressure on the basis of the second pulley pressure and first pulley pressure of first pulley. The hydraulic control means is configured to temporarily change the pilot pressure from set pressure to configure the line pressure identical to the second pulley pressure.

Hydraulic control device and method for controlling the same

A control apparatus for a continuously variable transmission () that includes a belt-type continuously variable transmission mechanism () and friction engagement elements (), () is disclosed. The control apparatus includes: an operation position detection section () configured to detect an operation position of a selection lever (); a selection control section () configured to execute a selection control for engaging the friction engagement elements (), () from a time point at which a switching from a non-travel range to a travel range is detected; a determination section () configured to determine engagement states of the friction engagement elements (); and a pulley pressure control section () configured to control a pulley pressure supplied to two pulleys (), (). A belt slippage during an engagement of clutches is suppressed while a load on an oil pump is reduced.

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

There is provided an oil pressure control device for a belt-type continuously variable transmission which includes two pulleys and a belt, wherein each of the two pulleys has a movable sheave which moves by oil pressure supplied to a hydraulic chamber, wherein the oil pressure control device calculates a request torque according to a running state, wherein when calculating the oil pressure which is supplied to the hydraulic chamber of the movable sheave on the basis of the request torque, the oil pressure control device reduces the request torque if the request torque is greater by a predetermined value or more than an actual input torque which is inputted to the belt-type continuously variable transmission. Accordingly, it is possible to provide an oil pressure control device for a belt-type continuously variable transmission with which undesirable vibration can be avoided by means of stable speed-ratio control.

Oil pressure control device for belt-type continuously variable transmission

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 control device for a belt-type continuously variable transmission CVT includes an engine, a belt-type continuously-variable transmitting mechanism; a forward/reverse switching mechanismincluding a forward clutchand a reverse brake; and a hydraulic control circuitconfigured to control a pulley hydraulic pressure and engagement-element pressures for the forward clutchand the reverse brake. The control device includes a selection control means for outputting a pulley hydraulic command to obtain an idle-time clamping pressure which is higher than an idle-time minimum pressure (idle-time MIN-pressure) calculated from an input torque, to the hydraulic control circuit, when the engineis in operation during a selection of N-range. A position of an element clearance generated in the belt can be maintained even if drag torque is inputted.

Control device for belt-type continuously variable transmission

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

The automatic transmission includes a first friction engagement element which is engaged when a first gear position is realized and disengaged when a second gear position is realized, a second friction engagement element which is engaged when the second gear position is realized and disengaged when the first gear position is realized, and a controller. The controller causes the second friction engagement element to slip by decreasing an instructional pressure for the second friction engagement element while running in the second gear position, and learns an engagement start pressure of the first friction engagement element based on a change in a differential rotation of the second friction engagement element, or in a parameter that changes in accordance with the differential rotation, at a time when an instructional pressure for the first friction engagement element is increased during the slip.

Automatic transmission and method for controlling same

Growing community of inventors

Isehara, Japan

Seiichiro Takahashi