Torgue converter lockup clutch control for an automatic transmission
This patent describes a converter lockup clutch system controlling an automatic transmission torque converter having an impeller adapted for driveable connection to an engine and a turbine hydrokinetically driveable to the impeller. It comprises: a torque converter clutch for alternately locking and releasing the impeller and turbine, having a first passage carrying converter release pressure to unlock the clutch and a second passage carrying apply pressure to lock the clutch; a source of line pressure, manual valve means for connecting the source of line pressure to an outlet when a low gear ratio is selected manually by a vehicle operator; first control means for producing first control pressure states representing commands to release and to apply the torque converter; and a converter clutch control valve means communicating with the outlet; the first control means and the source of line pressure when the first control means produce the converter apply pressure state, and for connecting the first passage to the source of line pressure when the low gear ratio is selected regardless of the pressure state produced by the first control means.
- Assignee:
- Ford Motor Co., Dearborn, MI
- Patent Number(s):
- US 4876923; A
- Application Number:
- PPN: US 7-217703A
- OSTI ID:
- 6956299
- Country of Publication:
- United States
- Language:
- English
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