Method and system for shift control of an automatic transmission
AssigneeToyota Jidosha Kabushiki Kaisha
InventorsHideki Yasue, Kagenori Fukumura
Life of this patent
Estimating the term…
Abstract
A shift control of an automatic transmission including a first transmission section and a second transmission section, which are capable of shifting automatically and independently of each other, and the first transmission section and the second transmission section are simultaneously or alternately shifted, to achieve multi-gear shifts, in which when shifting is to be achieved by shifting the first transmission section and the second transmission section in directions opposite to each other, and shifting is a down shift in the automatic transmission as a whole, such shifting is prohibited. The advantages of the multi-gear shifts are thus fully utilized to avoid high shift shocks.
Claims7
A method for shift control of an automatic transmission having at least a first transmission section and a second transmission section, which are capable of simultaneously or alternately shifting automatically and independently of each other to achieve multi-gear shifts, comprising the steps of:
- determining an indicated gear stage of said automatic transmission;
- testing if a shift to said indicated gear stage occurs by shifting said first transmission section and said second transmission section in directions opposite to each other;
- testing if said shift is a down shift in the automatic transmission as a whole;
- and
- prohibiting said shift when said shift occurs by shifting said first transmission section and said second transmission section in the directions opposite to each other and said shift is a down shift in the automatic transmission as a whole.
A system for shift control of an automatic transmission, comprising:
- a first transmission section and a second transmission section, which are capable of selectively shifting gear stages automatically and independently of each other, to thereby achieve multi-gear shifts;
- means for determining an indicated gear stage in accordance at least a with vehicle speed and engine load;
- means for controlling shifting of said first transmission section and of said second transmission section;
- means for driving said control means such that an actual operating gear stage corresponds to said indicated gear stage;
- means for detecting a shift direction;
- means for prohibiting a shift of said first transmission section and said second transmission section in directions opposite to each other when said shift comprises a down shift in the automatic transmission as a whole;
- and
- means for detecting an indicated gear stage corresponding to a non-prohibited shift and for permitting said non-prohibited shift.
Dependencies are inferred from the claim text.