US 6,149,547 AGranted

Gearshift control apparatus for automatic transmission which alters pre-inertia phase hydraulic pressure command parameters for engagement side clutch

AssigneeToyoda Jidosha Kabushiki Kaisha

InventorsHidehiro Oba, Hiroatsu Endo

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Abstract

In a gearshift control apparatus for an automatic transmission wherein the torque capacity of a release side clutch is gradually lowered, and the torque capacity of an engagement side clutch is gradually raised, whereby the release side clutch and the engagement side clutch are changed-over to effect a clutch-to-clutch gearshift; control means issues two control commands to the engagement side hydraulic control mechanism in a term which extends until an inertia phase begins since start of the gearshift control. A first hydraulic pressure command (D1) is issued for a predetermined time period. The first hydraulic pressure command (D1) is variable for adjusting the timing of the changeover between the clutches. The second hydraulic pressure command (D2) succeeding the first one is issued until the inertia phase begins. The second hydraulic pressure command is variable for adjusting the torque capacity of the engagement side clutch at the changeover. Thus, the timing of the clutch-to-clutch changeover is appropriately regulated without prolonging a gearshifting time period.

Claims7

Dependent claims

A gearshift control apparatus for an automatic transmission having a release side hydraulic control mechanism which controls a hydraulic pressure of a release side clutch, and an engagement side hydraulic control mechanism which controls a hydraulic pressure of an engagement side clutch, wherein a torque capacity of the release side clutch is gradually lowered by the release side hydraulic control mechanism, and a torque capacity of the engagement side clutch is gradually raised by the engagement side hydraulic control mechanism, so that the release side clutch and the engagement side clutch are changed-over to effect a clutch-to-clutch gearshift, comprising:

control means for issuing first and second hydraulic pressure commands for the hydraulic pressure of said engagement side clutch to said engagement side hydraulic control mechanism;
wherein
said control means issues said first hydraulic pressure command for a predetermined time period for adjusting a timing of the changeover between said clutches, and thereafter, issues said second hydraulic pressure command as a constant level command until the inertia phase begins for adjusting the torque capacity of said engagement side clutch at said changeover,
wherein said control means alters at least one of a command value of the fist hydraulic pressure command and said predetermined time, thereby to adjust the timing of said changeover between said clutches,
further comprising means for detecting a time period having lapsed since a timing at which a release command was issued to said engagement side clutch in a previous gearshift;
wherein said control means alters at least one of the command value of said first hydraulic pressure command and said predetermined time on the basis of the time period having lapsed since the timing at which the release command was issued to said engagement side clutch in the previous gearshift.

3 more elements

Dependencies are inferred from the claim text.

Facts

Application: 09/143,658Filed 31 Aug 1998
Priority: JP 9-2408685 Sep 1997
Granted: 21 Nov 2000
Term ends: Not estimatedThe source records don’t support an estimate.

Classification5 codes

F16H 61/061
By controlling rate of change of fluid pressure: using electric control means
F16H 59/72
Inputs being a function of gearing status: dependent on oil characteristics, e.g. temperature, viscosity
F16H 2061/0087
Characterised by a particular control method: adaptive control, e.g. the control parameters adapted by learning
F16H 2061/0477
Smoothing ratio shift: by suppression of excessive engine flare or turbine racing during shift transition