Line pressure control arrangement for automatic automotive transmission
US4955259A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Apr 14, 1989 |
| Grant date | Sep 11, 1990 |
| Priority date | — |
| Expiry date | Apr 14, 2009 |
Classification
- Technology area (CPC F)Mechanical Engineering; Lighting; Heating
- CPC primaryF16H2061/0255
- WIPO fieldMechanical elements
- WIPO sectorMechanical engineering
Abstract
During non-shift modes of transmission operation, the line pressure is controlled according to a basic line pressure control schedule. Upon a shift being initiated it is determined if the shift is being conducted under power ON or power OFF conditions by sensing the status of an idle switch associated with the engine throttle valve. In the case of a power ON shift, first and second maps which are record solenoid valve duty cycle in terms of engine load and vehicle speed are read out of memory and sequentially used one after the other to control the line pressure during the shifting. In the case of a power OFF shift, tables recorded in terms of duty cycle and vehicle speed are fetched and used one after the other. The changing from the first map or table to the second one is determined by comparing the rotational speed ratio which exists between the input and output shafts of the transmission with a shift solenoid control schedule which relates to the type of shift and which is being conducted and which is recorded in terms of gear ratio and engine load (e.g. throttle opening).
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.