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US 5,496,231 AGranted
Hydraulic control for a multi-speed power transmission
AssigneeGeneral Motors Corporation
InventorJames R. Eaton
Life of this patent
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AssigneeGeneral Motors Corporation
InventorJames R. Eaton
Estimating the term…
A hydraulic control for an automatically shifted power transmission has an electronically controlled governor pressure source which provides a speed and throttle sensitive pressure for controlling the shift points and trim boost in the transmission control. An inhibitor circuit is activated in the event of a discontinuance of the electrical control, resulting in maximum governor pressure, to permit selected vehicle operation in one forward ratio and a reverse ratio. Each ratio interchange is controlled by a respective shift valve and clutch control valve. Each clutch control valve has an integral trim control which is effective to control the pressure rise in the on-coming clutch without bypassing fluid to an exhaust. Also during a ratio interchange, an off-going clutch is controlled at a reduced pressure during a portion of the ratio interchange.
In combination, a multi-speed transmissions and control comprising:
In combination, a multi-speed transmissions and control comprising:
Dependencies are inferred from the claim text.