Coasting downshift control for automatic transmissions
US7089102B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Sep 12, 2003 |
| Grant date | Aug 8, 2006 |
| Priority date | — |
| Expiry date | Aug 10, 2024 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY02T10/60
- WIPO fieldMechanical elements
- WIPO sectorMechanical engineering
Abstract
An automatic transmission ratio shift control system and method for a powertrain having an engine and multiple-ratio gearing controlled by friction elements actuated by hydraulic pressure, an electronic controller for establishing torque transitions among the friction elements as the gear ratio changes, the engine speed being controlled by an electronic throttle control. The strategy employs an electronic throttle and closed loop engine speed control and uses fuel and air as an energy source to increase engine speed during a power-off downshift. The engine speed is boosted to a level close to the synchronous speed in conjunction with release of the off-going friction element. The on-coming friction element is then applied as the engine speed approaches a desired speed. The engine speed increase is timed to lead an increase in torque converter speed.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.