Extreme cold logic limiting shifts to first and third speeds
US6024668A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Apr 1, 1999 |
| Grant date | Feb 15, 2000 |
| Priority date | — |
| Expiry date | Apr 1, 2019 |
Classification
- Technology area (CPC F)Mechanical Engineering; Lighting; Heating
- CPC primaryF16H2061/1204
- WIPO fieldMechanical elements
- WIPO sectorMechanical engineering
Abstract
An automatic transmission control system is provided with extreme cold logic wherein when the transmission oil temperature is below a predetermined temperature so as to cause the transmission oil to have extremely viscus characteristics, the transmission prevents faulty shifting by limiting shifts between first and third gears. The first gear is obtained by application of a single hydraulically controlled clutch element in combination with a freewheel clutch element while the third gear operation can be obtained by engagement of a second clutch element in combination with the first clutch element. Since the shift between first and third gears only requires the application of the second clutch element in combination with the already engaged first clutch element, there is no risk of torque overlap between elements.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.