Nissan Motor Company Limited

Jatco Corporation

Tatsuo Wakahara

Shigeki Shimanaka

Masahiro Yamamoto

Hiroshi Yamaguchi

Yuji Kato

Shigeru Ishii

Shinsuke Nakazawa

Hiroshi Asano

Hiroyasu Tanaka

Hiroshi Sasaki

Kazuhiro Ishigami

Yoshihisa Kodama

Kenichiro Murakami

Hisao Nobu

Satoshi Sakakibara

Shinichi Takenouchi

Kazuyoshi Iwanaga

Koichi Hayasaki

Tateki Jozaki

Midori Yamaguchi

Youhei Ishikawa

Akira Watanabe

Yutaka Suzuki

Kazutaka Adachi

Masahiro Iriyama

Akihiro Ueki

Makoto Sawada

Takuichiro Inoue

Toshiji Iida

Kazuhiro Takatori

Kenichi Gotou

Hideki Oshita

Tetsuya Shimada

Masayuki Kobayashi

Taichirou Yokoyama

Shinich Takenouchi

Kenichirou Murakami

Masaki Ohki

Chusaku Udagawa

During a downshift of a belt-drive continuously variable transmission, occurring owing to vehicle deceleration, a CVT controller foretells that a slippage between a drive belt and each of primary and secondary variable-width pulleys tends to occur, when a primary pulley pressure is less than a first predetermined pressure level and a primary pulley speed is less than a first predetermined rotational speed. When the belt slippage has been foretold, the CVT controller inhibits the primary pulley pressure from dropping by setting an actual transmission ratio calculated before a set time period from a time when the slippage has been foretold or a transmission ratio of a relatively higher speed side as compared with a ratio-change operating state obtained when the slippage has been foretold, to a desired transmission ratio, or by relatively rising a line pressure as compared with a line pressure level produced when the slippage has been foretold.

Slippage prevention apparatus of belt-drive continuously variable transmission for automotive vehicle

In control apparatus and method for an automotive vehicle, the vehicle having a continuously variable transmission associated with a vehicular engine and including a belt that transmits a revolution of a primary pulley to a secondary pulley that is enabled to make a gear shift by modifying a pulley ratio between the primary and secondary pulleys with a hydraulic, a determination is made as to whether a belt slip between at least one of the primary and the secondary pulleys occurs and an output section outputs a signal to command an engine control unit to increase an engine speed by a predetermined engine speed when the belt slip is determined to occur.

Control apparatus and method for automotive vehicle in which a belt-type continuously variable transmission is equipped with a belt slip preventive feature

There are provided with a determination means for determining whether or not the correlation between the pressure value detected by the primary pressure sensor and the pressure value detected by the secondary pressure sensor is an actually impossible relation (Step), and a switchover means for switching over to an open control while prohibiting a feedback control when the correlation is determined to have become a relation actually impossible by the determination means (Step). Presence or absence of a fault to the primary pressure sensor or the secondary pressure sensor (particularly, fault of fixed output voltage) is judged based on the correlation between the output voltage of the primary pressure sensor and the output voltage of the secondary pressure sensor to prohibit the control of a primary pressure and a secondary pressure using the hydraulic pressure sensors when it is judged that there is a fault.

Transmission controller of V-belt type continuously variable automatic transmission

Hydraulic control system and method for an automatic transmission. The hydraulic control system includes a hydraulic pressure source, a flow rate control valve having a spool with an orifice and a drain hole, stroke position determining means, and pressure regulator means. The stroke position determining means determines that the spool is displaced from a large spool-stroke position where a communication area of the drain hole is not less than a first predetermined area, to a small spool-stroke position where the communication area is not more than a second predetermined area. The pressure regulator means regulates a hydraulic oil pressure downstream of the orifice and corrects the hydraulic oil pressure downstream of the orifice by adding a predetermined correction amount for a first predetermined time when the stroke position determining means determines that the spool is displaced from the large stroke position to the small stroke position.

System and method for hydraulically controlling automatic transmission

A speed change ratio control unit for a continuously variable transmission that uses a step motor as a driving actuator of a speed change control valve that compares a variable ASTP representing a step position of the step motor and a step position BSTP of the step motor that is necessary for realizing a desired speed change ratio at every predetermined operation cycle, and if ASTP&#x2260;BSTP is satisfied determines that a step-out has occurred on the step motor.

Speed change ratio control unit for continuously variable transmission

In a V-belt type CVT, an actual-shift-ratio corresponding operated position of a step motor is calculated through conversion of an actual shift ratio expressed by the rotational-speed ratio between primary and secondary pulleys. A displacement amount is calculated between the actual-shift-ratio corresponding operated position of the step motor and an actual position thereof. A correction amount of the line pressure is calculated to reduce the displacement amount, and the line pressure is corrected in accordance therewith.

System and method of controlling line pressure for V-belt type continuously variable transmission

A lock-up control device controls a lock-up clutch in a torque converter. The lock-up clutch is engaged by supplying a lock-up control pressure. The torque converter transmits torque via oil in a torque converter chamber when the lock-up clutch is disengaged, and transmits torque directly when the lock-up clutch is engaged. In the lock-up state, the oil pressure in the torque converter chamber is decreased by discharging oil in the torque converter chamber. By providing a circuit which leads oil discharged from the torque converter chamber to a lubricating part of the transmission, the balance between the inflowing oil amount and outflowing oil amount is improved, and oil insufficiency is prevented.

Lock-up control for device torque converter

A valve ( ) causes fluid pressures to act individually on plural frictional elements (A, B) of an automatic transmission so as to selectively lock the rotation of the frictional elements (A, B). A control unit ( ) determines that the automatic transmission has an interlock tendency when the fluid pressures acting on the frictional elements (A, B) detected by pressure sensors ( ) are both equal to or greater than a predetermined pressure. Completion of a gear position change-over is detected by a sensor ( ), and the control unit ( ) does not determine the interlock tendency until a predetermined time &Dgr;t has elapsed after the gear position change-over is complete. In this way, an incorrect determination is prevented by avoiding the determination in a period when the pressures are unstable in a period immediately after the gear position change-over of the automatic transmission.

Fault determining device and method for hydraulically operated automatic transmission

A lock-up control device comprises an inlet circuit which supplies oil to a torque converter chamber, an outlet circuit which discharges oil from the torque converter chamber, a signal output circuit which outputs a signal pressure according to a required engaging capacity of a lock-up clutch, and a lock-up control valve which outputs a lock-up control pressure according to the signal pressure from the signal output device. A lock-up control pressure which is fed back is input to the lock-up control valve so as to decrease the lock-up control pressure, and the pressure of the inlet circuit and pressure of the outlet circuit are input to the lock-up control valve so as to increase the lock-up control pressure. In this way, the pressure in the converter chamber is accurately reflected, and the lock-up control pressure is controlled so that a pressure differential between the lock-up control pressure and the torque converter chamber is a desired value.

Lock-up control device for torque converter

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

A releasable coupling control system in combination with an electronic engine control unit executable a fuel cutoff mode during vehicle deceleration and re-startable a fuel-supply recovery mode as soon as an engine speed drops below a predetermined threshold value, for controlling engaging and disengaging operations of a releasable coupling device placed in an automotive power train between an engine and drive wheels, comprises a wheel-speed sensor for detecting a drive-wheel speed to generate a drive-wheel speed indicative signal, and a controller being configured to be responsive to the drive-wheel speed indicative signal for moderately releasing the releasable coupling device at a moderate turn-off mode when the drive-wheel speed indicative signal value drops below a first predetermined value, and for quickly releasing the releasable coupling device at a quick turn-off mode when the drive-wheel speed indicative signal value drops below a second predetermined value.

System for controlling engaging and disengaging operations of releasable

A lockup control apparatus of a torque converter for a vehicle comprises a coast condition detecting section for detecting coast running of a vehicle, a lockup clutch slip detecting section for detecting a target slip generated between the input and output elements of the torque converter and a slip start capacity storing section, and a coast lockup control section for detecting a lockup capacity. The slip start capacity storing section detects a slip start capacity by once decreasing the lockup capacity to the sum of a last stored slip start capacity and a preset capacity and stores the slip start capacity while updating it. During the coast running a coast lockup control section controls the lockup capacity at a minimum lockup engagement capacity which is the sum of the newest slip start capacity and a predetermined capacity.

Lockup control apparatus of torque converter

A hydraulic-pressure control system for a four-wheel drive vehicle with a hydraulic-pressure operated transfer clutch, which is responsive to a controlled clutch pressure applied thereto to distribute a driving torque passing from a transmission between main drive wheels and auxiliary drive wheels, comprises a pilot-operated directional control valve connected to the transfer clutch for cutting off a supply of hydraulic fluid of the controlled clutch pressure to the transfer clutch and for directing hydraulic fluid of the controlled clutch pressure to the transfer clutch. The system includes a clutch pressure control valve provided upstream of the directional control valve, which pressure control valve is responsive to an external pilot pressure for producing the controlled clutch pressure, and a duty-ratio controlled solenoid valve for decreasingly adjusting the external pilot pressure to be output to the pressure-reduction valve in accordance with an increase in a duty ratio. A controller is provided for forcibly outputting a duty-cycle controlled exciting current of a predetermined high duty ratio such as 100% to the duty-ratio controlled solenoid valve to reduce the controlled clutch pressure to a low pressure level (preferably a minimum clutch pressure) when the directional control valve is maintained at the cut-off position in case of 4L range wherein the transmission is loaded heavier.

Hydraulic-pressure control system for four-wheel drive vehicle with

There is disclosed a motor vehicle having a set of front wheels, a set of rear wheels, an engine, and a transmission driven by the engine and having a transmission output shaft. The motor vehicle further has a transfer including a variable torque trasmitting (VTT) clutch for varying a distribution of torque between the set of front wheels and the set of rear wheels depending upon degree of engagement thereof. A clutch activating pressure is generated and transmitted to the VTT clutch under the control of a mode selector valve.

Transfer for motor vehicle

A working fluid pressure control device for a hydraulic control system of a V-belt type continuously variable transmission comprises a line pressure regulator valve, a pressure reducer valve, a pressure modifier valve, in which the line pressure regulator valve developing a regulated line pressure for cylinder chambers of driving and driven pulleys of the transmission from a source pressure applied from a hydraulic pump driven by an engine associating with the transmission, the pressure reducer valve developing a reduced output pressure for a forward clutch and a reverse brake of the transmission from a source pressure supplied from the line pressure regulator valve, and the pressure modifier valve developing a pilot pressure for the line pressure regulator valve. There is provided a line pressure characteristics changing means which changes a characteristics of the line pressure relating to at least a transmission ratio, between a higher characteristics and a lower characteristics corresponding to whether a lock-up mechanism of a torque converter of the transmission is executing locking-up or not.

Growing community of inventors

Kawasaki, Japan

Tatsuo Wakahara