Control system for controlling the pressure of the oncoming servo hydraulic pressure based on a predicted time to sync from output shaft acceleration in automatic transmission
US5411451A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Nov 27, 1992 |
| Grant date | May 2, 1995 |
| Priority date | — |
| Expiry date | Nov 27, 2012 |
Classification
- Technology area (CPC F)Mechanical Engineering; Lighting; Heating
- CPC primaryF16H2061/0078
- WIPO fieldMechanical elements
- WIPO sectorMechanical engineering
Abstract
A control system is provided for servo hydraulic pressure in an automatic transmission. Upon downshifting, one of first and second frictional engagement devices is released while the other is engaged. A directional control valve is provided to feed or drain servo hydraulic pressure to selectively engage or release the first and second devices. The hydraulic pressure is regulated by a pressure regulator under the control of an electronic control unit. Detectors are also provided to determine input rotation and torque, respectively. The regulator is interposed between the directional control valve and the engaged device. The regulator is controlled to maintain the servo hydraulic pressure at a predetermined value under the control of the electronic control unit until predetermined input rotation is detected and then to gradually raise the servo hydraulic pressure under the control of the electronic control on the basis of the value of input torque.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.