Jatco Corporation

Nissan Motor Company Limited

Yasutaka Kawamura

Jihoon Kang

Masaki Watanabe

Hiroyasu Tanaka

Shigeki Shimanaka

Hirofumi Okahara

Tatsuo Ochiai

Donggyun Park

Masato Koga

Mitsuru Watanabe

Satoshi Takizawa

Hirofumi Michioka

Masatoshi Akanuma

Kazuya Murota

Junya Takayama

Takashige Hinami

Yoshichika Hagiwara

Toshiyasu Yamaguchi

Takeshi Oohori

Masaoki Horio

In a control device for an automatic transmission having a flow control mechanism that causes a part of a working oil discharged from a mechanical oil pump to flow into the mechanical oil pump when a differential pressure between an upstream side and a downstream side of a narrowed portion increases beyond a predetermined value, the narrowed portion being provided in a discharge passage through which the working oil discharged from the mechanical oil pump flows, a line pressure is raised when an oil temperature of the working oil is equal to or higher than a predetermined oil temperature and an engine torque is equal to or smaller than a predetermined engine torque.

Control device and control method for automatic transmission

An abnormal oil pressure reduction determining device has an oil pressure sensor which detects a real oil pressure, a sensor which detects a vehicle running state, and a controller which sets an oil pressure command value for an oil pressure control mechanism. The controller computes the lower limiting oil pressure which is possible in the present vehicle running state, and when the real oil pressure is less than this lower limiting oil pressure and the pressure difference between the real oil pressure and oil pressure command value exceeds a reference value, determines that there is an abnormal pressure reduction due to a fault in the oil pressure control mechanism. Even if the oil pressure of the transmission has dropped abnormally due to some reason, the abnormal oil pressure reduction determining device determines the situation without fail.

Abnormal oil pressure reduction determination device for vehicle transmission

A vehicle is provided with an engine (), an automatic transmission () connected to the engine (), a detection device () which detects an operating state of the transmission (), and a torque regulating mechanism () which regulates a torque of the engine. When the operating state of the transmission () is in a predetermined drive state and the torque of the engine () is to be reduced, a selection is made, based on the operating state of the transmission (), between a first torque reduction control whereby the torque of the engine () is reduced rapidly and temporarily, and a second torque reduction control whereby the torque of the engine () is reduced continuously, and more smoothly than in the first torque reduction control. The torque of the engine () is then reduced by the selected one of the first torque reduction control and the second torque reduction control.

Control apparatus for vehicle provided with an automatic transmission, and method of controlling the same

There is provided an engine torque control apparatus that is comprised of a torque-down amount calculating section to which the throttle valve opening and the engine speed are inputted and which calculates the torque-down amount based on the inputted values, an inertia correction amount calculating section that calculates the correction amount for inertia of each component part (inertia discharged torque), a friction correction amount calculating section that calculates the correction amount for friction generated by a belt CVT (friction discharged torque), a torque-down amount correcting section that corrects the torque-down amount based on the calculated correction amounts, and an engine torque control section that controls engine torque. Since the engine torque is controlled with inertia and friction discharged torque of each component part being taken into account, the upper limit of the torque inputted to an automatic transmission can be accurately controlled to the value of the allowable input torque of the automatic transmission.

Engine torque control apparatus

An engine torque control apparatus for controlling the output torque of an engine () connected to a transmission () in a vehicle has a temperature sensor () for detecting the temperature of oil used by the transmission (), and a controller () for limiting the output torque of the engine to an engine torque limit or less. The controller () functions to compare the oil temperature with a specific temperature, to set the engine torque limit to a first limiting value when the oil temperature is equal to or less than the specific temperature, and to increase the engine torque limit at a predetermined increase rate when the oil temperature exceeds the specific temperature.

A vehicle engine () is connected with a belt-type continuously variable transmission () via a clutch (). The transmission () transmits torque via a belt () between a pair of pulleys (), and varies the transmission torque according to a supply of oil pressure. The clutch () engages by means of oil pressure supplied as a shift lever is changed over from a neutral range to a drive range. An oil pressure supplying device () supplies the oil pressure required to transmit torque between the belt () and the pulleys (), and the oil pressure for engaging the clutch (). Slippage between the belt () and the pulleys () is prevented during engagement of the clutch () by restricting the output torque of the engine () over a predetermined period of time.

Prevention of slippage in belt-type continuously variable transmission

A control system for an automatic transmission ( ) includes an oil pressure control mechanism ( ) for supplying an oil pressure to the transmission ( ), and sensor ( ) for detecting the oil pressure supplied from the oil pressure control mechanism ( ) to the transmission ( ). System controller ( ) calculates a maximum torque transmittable by the transmission ( ) based on a speed ratio of the transmission ( ) and the detected oil pressure; calculate an engine torque reduction amount from the difference between the torque being inputted into the transmission ( ) and the maximum transmittable torque; and reduce the torque of an engine ( ) according to the engine torque reduction amount.

Control system and control method for automatic transmission

A shift control system of a toroidal CVT for a vehicle is arranged to calculate a command gear ratio by adding a desired gear ratio and a torque shift compensation quantity for compensating a difference between the desired gear ratio and an actual gear ratio which difference is generated by a shifting operation of the toroidal CVT, and to set a magnitude of the torque shift compensation quantity employed in an automatic shift range to be larger than a magnitude of the torque shift compensation quantity employed in other shift range except for the automatic shift range when the actual gear ratio is in a first gear ratio region except for a second gear ratio region including a largest gear ratio.

Shift control system of continuously variable transmission

A shift control system for a toroidal CVT employs a shift technique for setting a torque shift compensation quantity so as to be increased as an actual gear ratio approaches a low-speed side gear ratio region including a lowest-speed gear ratio and so as to be decreased when the actual gear ratio is in the low-speed side gear ratio region. Further, the shift control system is arranged to select a gear ratio in a low-speed side gear ratio region after a gear ratio in a high-speed side gear ratio region is selected.

Shift control system for continuously variable transmission

A toroidal continuously variable transmission ( ) transmits the rotation output of a vehicle engine ( ) at an arbitrary speed ratio. The toroidal continuously variable transmission ( ) comprises two disks ( ) disposed coaxially, and power rollers ( ) in contact with the two disk ( ). Surface of the two disks ( ) and of the power roller ( ) are provided with oil. The oil temporarily collected in oil pan ( ). The oil temperature in the oil pan ( ) is detected by a sensor ( ), and slip of the power rollers ( ) is prevented by suppressing the output torque of the engine ( ) when the oil temperature is low.

Slip preventing control of toroidal continuously variable transmission

An alarm is emitted when a vehicle attempts to start when the speed ratio of a toroidal continuously variable transmission is small. A sensor ( ) detects that the speed ratio is smaller than a predetermined range. A microprocessor ( ) controls an alarm ( ) to operate when an ignition switch ( ) is in a position for starting an engine, while the speed ratio is smaller than the predetermined range.

Small speed ratio detection and control devices for vehicle start

In a line pressure control unit of an automatic transmission for a vehicle which performs feedback control of a line pressure of an automatic transmission, comprising: a line pressure solenoid valve( ) which adjusts a line pressure, a sensor which detects a real line pressure and a microprocessor ( ) which controls the line pressure solenoid valve. The microprocessor is programmed to: calculate a required line pressure(P ) according to the running state of the vehicle, calculate a target line pressure(P ) from the required line pressure(P ), the target line pressure(P ) being modified by a safety factor(S ) for line pressure correction, and calculate a line pressure difference(&Dgr;P ) between the required line pressure(P ) and the real line pressure(P ) and add a feedback control amount(&Dgr;P ) according to the line pressure difference to the target line pressure to calculate a command line pressure(P ) control the line pressure valve based on the command line pressure(P ).

Line pressure control unit of automatic transmission

A clutch ( ) which connects an engine to a toroidal continuously variable transmission ( ) is engaged and transmits a torque to the transmission ( ) according to a line pressure. The toroidal continuously variable transmission ( ) transmits the torque also according to the line pressure. A microprocessor ( ) calculates a first pressure required to engage the clutch ( ) in the idle running state of the engine ( ), calculates a second pressure required for torque transmission of the clutch ( ) based on a torque transmission amount of the clutch ( ) (S ), and calculates a third pressure required for torque transmission of the continuously variable transmission ( ) based on the torque transmission amount of the clutch ( ) and the speed ratio of the continuously variable transmission ( ) (S ). Insufficiency of line pressure when the vehicle starts is prevented by controlling the line pressure to be equal to the maximum value of the first pressure, second pressure and third pressure when the load of the engine ( ) is equal to a greater than a first set value until a first set time has elapsed after the supply of the line pressure to the clutch ( ) is started.

Line pressure control device of continuously variable transmission

A controller (,) for a line pressure control device of a transmission (,) compares a CVT pressure P,and a clutch pressure P,when the rotation speed of an engine (,) is low and sets the higher of the two as a target line pressure P,. When the rotation speed of an engine (,) is high, the CVT pressure P,, the clutch pressure P,and a lubrication pressure P,are compared, and the highest of the three is set as the target line pressure P,. Thus it is possible to reduce pump noise as well as satisfy oil pressure requirements in the transmission (,) by switching the method of setting a line pressure in response to the rotation speed of the engine (,).

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Atsugi, Japan

Yasutaka Kawamura