Control means for vehicle automatic transmissions

Claim 2

A vehicle automatic transmission including a hydraulic torque converter having an input member connected with an engine output shaft and an output member connected with a multiple stage transmission gear mechanism which has a plurality of gear stages, gear stage selecting means including hydraulic actuator means for selecting a desired one of said gear stages, a hydraulic circuit including solenoid valve means for controlling hydraulic pressure supplied to said actuator means, speed detecting means for detecting a rotating speed of said output member of said torque converter and producing a speed signal, load detecting means for detecting engine load and producing a load signal, shift control means including a shift control map having a shift down control line which is common to adjacent gear stages and based on the rotating speed of said output member of the torque converter and the engine load with which the torque converter is operated with a torque ratio of substantially one within a speed ratio range not exceeding one, and a plurality of shift up control lines which are shifted to a high speed side with respect to the shift down control line by an amount corresponding to a change in speed of the torque converter output member when a shift up operation is carried out from a gear stage which is actually in use, said shift down control line being determined in accordance with the speed ratio at which the torque converter is operated with a torque ratio of substantially one, except in a kick down zone wherein the engine load is above a first predetermined value, and except in an extremely light load zone wherein the engine load is below a second predetermined value which is lower than the first predetermined value, said shift control means further including means for performing a cycle of shift control operation to compare the speed signal and the load signal with said shift control map and to provide modified shift control lines which have hysteresis with respect to the shift down control line and the shift up control line and for comparing the speed signal and the load signal with the modified shift control lines to produce a shift control signal for energizing the solenoid valve means to perform a required gear shifting operation.

Claim 3

A vehicle automatic transmission in accordance with claim 1 in which said transmission gear mechanism includes planetary gear mechanisms.

Claim 4

A vehicle automatic transmission in accordance with claim 1 in which the hydraulic circuit includes pilot pressure operated shift valves, said solenoid valve means being provided for controlling pilot pressures for the shift valves.

Claim 5

A vehicle automatic transmission in accordance with claim 1 in which said torque converter includes lock up clutch means which is controlled by said hydraulic circuit, said shift control means is provided also for controlling engagement of said lock up clutch means.

Claim 6

A vehicle automatic transmission in accordance with claim 1 in which said shift control map includes a plurality of shift up control lines respectively for respective pairs of adjacent gear stages, and a skip shift up control line for a two gear stage shift up, said shift control means including means for selecting one of the shift up control lines corresponding to the gear stage which is actually in use.

Claim 7

A vehicle automatic transmission in accordance with claim 5 in which said skip shift up control line is in a high turbine speed and low engine load range.

Claim 8

A vehicle automatic transmission in accordance with claim 6 in which said shift control map includes a skip shift down control line for a two gear stage shift down.

Claim 9

A vehicle automatic transmission in accordance with claim 7, in which said transmission gear mechanism includes planetary gear mechanisms and the hydraulic circuit includes pilot pressure operated shift valves, said solenoid valve means being provided for controlling pilot pressure for the shift valves.

Claim 10

A vehicle automatic transmission including a hydraulic torque converter having an input member connected with an engine output shaft, an output member connected with a multiple stage transmission gear mechanism which has a plurality of gear stages and lock-up clutch means for releasably connecting the input member with the output member, gear stage selecting means including hydraulic actuator means for selecting a desired one of said gear stages, a hydraulic circuit including solenoid valve means for controlling hydraulic pressure supplied to said actuator means, speed detecting means for detecting a rotating speed of said output member of said torque converter and producing a speed signal, load detecting means for detecting engine load and producing a load signal, shift control means including a shift control map having a shift down control line which is common to adjacent gear stages and based on the rotating speed of said output member of the torque converter and the engine load with which the torque converter is operated with a torque ratio of substantially one within a speed ratio range not exceeding one, a plurality of shift up control lines which are shifted to a high speed side with respect to the shift down control line by an amount corresponding to a change in speed of the torque converter output member when a shift up operation is carried out from a gear stage which is actually in use, and a lock-up control line which is shifted to a high speed side with respect to the shift down control line, a lock-up release control line which is substantially identical with said shift down control line, said shift down control line being determined in accordance with the speed ratio at which the torque converter is operated with a torque ratio of substantially one within a range not exceeding one, except in a kick down zone wherein the engine load is above a first predetermined value, and except in an extremely light load zone wherein the engine load is below a second predetermined value which is lower than the first predetermined value, said shift control means further including means for performing a cycle of shift control operation to compare the speed signal and the load signal with said shift control map, and to provide modified shift control lines which have hysteresis with respect to the shift down control line and the shift up control line and for comparing the speed signal and the load signal with the modified shift control lines to produce a shift control signal for energizing the solenoid valve to perform a required gear shifting operation and clutch engaging and releasing operations.

Claim 11

A vehicle automatic transmission including a hydraulic torque converter having an input member connected with an engine output shaft, an output member connected with a multiple stage transmission gear mechanism which has a plurality of gear stages and lock-up clutch means for releasably connecting the input member with the output member, gear stage selecting means including hydraulic actuator means for selecting a desired one of said gear stages, a hydraulic circuit including solenoid valve means for controlling hydraulic pressure supplied to said actuator means, speed detecting means for detecting a rotating speed of said output member of said torque converter and producing a speed signal, load detecting means for detecting engine load and producing a load signal, shift control means including a shift control map having a shift down control line which is common to adjacent gear stages and based on the rotating speed of said output member of the torque converter and the engine load with which the torque converter is operated with a torque ratio of substantially one within a speed ratio range not exceeding one, a plurality of shift up control lines which are shifted to a high speed side with respect to the shift down control line by an amount corresponding to a change in speed of the torque converter output member when a shift up operation is carried out from a gear stage which is actually in use, and a lock-up control line which is shifted to a high speed side with respect to the shift down control line, a lock-up release control line which is substantially identical with said shift down control line, said shift down control line being determined in accordance with the speed ratio at which the torque converter is operated with a torque ratio of substantially one within a range not exceeding one, except in a kick down zone wherein the engine load is above a first predetermined value, and except in an extremely light load zone wherein the engine load is below a second predetermined value which is lower than the first predetermined value, said shift control means further including means for performing a cycle of shift control operation to compare the speed signal and the load signal with said shift control map, and to provide modified shift control lines which have hysteresis with respect to the shift down control line and the shift up control line and for comparing the speed signal and the load signal with the modified shift control lines to produce a shift control signal for energizing the solenoid valve to perform a required gear shifting operation and clutch engaging and releasing operations.

Claim 12

A vehicle automatic transmission in accordance with claim 9 in which said transmission gear mechanism includes planetary gear mechanisms.

Claim 13

A vehicle automatic transmission in accordance with claim 9 in which the hydraulic circuit includes pilot pressure operated shift valves, said solenoid valve means being provided for controlling pilot pressures for the shift valves.

Claim 14

A vehicle automatic transmission in accordance with claim 9 in which said shift control map includes a plurality of shift up control lines respectively for respective pairs of adjacent gear stages and a skip shift up control line for a two stage shift up, said shift control means including means for selecting one of the shift control lines corresponding to the gear stage which is actually in use.

Claim 15

A vehicle automatic transmission in accordance with claim 12 in which said skip shift up control line is in a high turbine speed and low engine load range.

Claim 16

A vehicle automatic transmission in accordance with claim 13 in which said shift control map includes a skip shift down control line for a two gear stage shift down.

Claim 17

A vehicle automatic transmission in accordance with claim 14 in which said transmission gear mechanism includes planetary gear mechanisms and the hydraulic circuit includes pilot pressure operated shift valves, said solenoid valve means being provided for controlling pilot pressures for the shift valves.