US 6,480,777 B1Granted

Hydraulic pressure control device for automatic transmission

AssigneeAisin Seiki Kabushiki Kaisha

InventorsKatsutoshi Sato, Yasuo Shirai, Akira Aikawa, Hiroaki Kato, Atsumi Ohara

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Abstract

A hydraulic pressure control device for an automatic transmission is adapted to smoothly change the slip amount of the automatic transmission when a clutch to clutch shift control is performed. The hydraulic pressure control device uses a reference model showing a behavior with an output corresponding to a predetermined slip amount which smoothly varies over time with respect to a target slip amount which varies in a stepped manner. The hydraulic pressure is applied to a release side frictional engagement element using a controller CEMM (s) which shows a behavior such that the controller CEMM(s) and a controlled object P(s) are collaborated to correspond to the reference model. The controller CEMM(s) and the controlled object P(s) have the hydraulic pressure applied to the release side frictional engagement element of the automatic transmission as an input and the slip amount of the automatic transmission as an output.

Claims15

Dependent claims

A method of controlling an automatic transmission comprising:

achieving a predetermined shift by maintaining a plurality of frictional engagement elements under an engagement condition or a disengagement condition by controlling hydraulic pressure applied to the frictional engagement elements, the plurality of frictional engagement elements including a release side frictional engagement element and an engagement side frictional element;
generating a slip by reducing a transmission torque of the release side frictional engagement element by reducing the hydraulic pressure applied to the release side frictional engagement element which is under the engagement condition before a shift change and is changed to the disengagement condition after the shift change;
performing the shift change by increasing the transmission torque of the engagement side frictional element by increasing the hydraulic pressure applied to the engagement side frictional element which is under the disengagement condition before the shift change and is changed to the engagement condition after the shift change;
using a reference model having a behavior such that an output is determined to be a predetermined slip amount which smoothly varies over an elapse of time with respect to a target slip amount that varies in a stepped manner;
and
controlling the hydraulic pressure applied to the release side frictional engagement element using a controller which exhibits a behavior corresponding to the reference model by collaboration of a controlled object and the controller for which a hydraulic pressure applied to the release side frictional engagement element is determined to be an input and a slip amount of the automatic transmission is determined to be an output.

3 more elements

A hydraulic pressure control device in an automatic transmission that includes a plurality of frictional engagement elements adapted to be maintained under an engagement condition or a disengagement condition to achieve a predetermined shift by controlling hydraulic pressure applied to the frictional engagement elements, the plurality of frictional engagement elements including a release side frictional engagement element and an engagement side frictional element, with slip being generated by reducing a transmission torque of the release side frictional engagement element through reduction of the hydraulic pressure applied to the release side frictional engagement element which is under the engagement condition before a shift change and is changed to the disengagement condition after the shift change, and with the shift change being performed by increasing the transmission torque of the engagement side frictional element through increase of the hydraulic pressure applied to the engagement side frictional element which is under the disengagement condition before the shift change and is changed to the engagement condition after the shift change, the hydraulic pressure control device comprising:

a reference model exhibiting a behavior such that an output is determined to be a predetermined slip amount which smoothly varies over time relative to a target slip amount that varies in a stepped manner;
and
a controller which controls the hydraulic pressure applied to the release side frictional engagement element, the controller having a behavior corresponding to the reference model by collaboration of a controlled object and the controller for which a hydraulic pressure applied to the release side frictional engagement element is determined to be an input and a slip amount of the automatic transmission is determined to be an output.

Dependencies are inferred from the claim text.