Event sequenced clutch-to-clutch downshift for an electronically controlled transmission
US4796490A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Dec 22, 1987 |
| Grant date | Jan 10, 1989 |
| Priority date | — |
| Expiry date | Dec 22, 2007 |
Classification
- Technology area (CPC F)Mechanical Engineering; Lighting; Heating
- CPC primaryF16H2061/0209
- WIPO fieldMechanical elements
- WIPO sectorMechanical engineering
Abstract
A clutch-to-clutch power-on downshift in a motor vehicle automatic transmission is initiated by reducing the torque capacity of the off-going clutch, permitting the transmission input speed to increase toward its post shift value. When the slippage across the off-going clutch exceeds a reference, the reduction of its torque capacity is suspended, permitting continued increase of the transmission input speed. When the slippage across the on-coming clutch falls below a reference value, the on-coming and off-going clutches are concurrently applied and released to complete the shift. The transmission input speed substantially achieves its post shift value at the time of such apply and release, resulting in reduced shift-related output torque disturbance.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.