Automatic transmission control for an automotive vehicle driveline having fail-safe logic
AssigneeFord Motor Company
InventorsJames P. McCarthy, Richard E. Byler
Life of this patent
Estimating the term…
Abstract
A control system for operating the clutch and brake elements of a multiple speed ratio transmission includes a manual valve that opens line pressure to a transfer valve, which in its first state pressurizes a feed line through which any of the clutches and servos may be selectively pressurized. In its second state, the transfer valve pressurizes the clutches whose engagement that produces a predetermined speed ratio. The detector valve moves the transfer valve to the second state if the combination of pressurized clutches and servos is other than the combination that produces a drive ratio in normal operation.
Claims8
An automatic power transmission mechanism for delivering torque from a power input member to a power output member comprising:
- multiple speed ratio torque transmitting gearing establishing torque delivery paths between the input member and the output member;
- multiple fluid pressure operated clutch and servo means for connecting and holding elements of said gearing;
- a fluid pressure source;
- a valve for regulating the fluid pressure from said pressure source to line pressure;
- a manual valve supplied with fluid from the regulating valve for communicating fluid at line pressure to a first outlet when the manual valve is disposed in a forward drive position or to a second outlet when the manual valve is disposed other than in the forward drive position;
- transfer valve means normally in a first state at which communication is open between said manual valve first outlet and a feedline, movable to a second state at which communication is open between said manual valve first outlet and a fail-safe line that carries fluid to those clutch and servo means whose pressurization produces a predetermined speed ratio;
- actuating means supplied with fluid from the feedline for selectively opening and closing communication between said feedline and selected clutch and servo means whereby said clutch and servo means are engaged and disengaged and the transmission ratios thereby produced;
- detector valve means continuously communicating with the output of the actuating means disposed in a first state if the output of the actuating means is the output required for normal operation in a transmission drive ratio and disposed in a second state if the output of the actuating means is other than the output required for normal operation in a transmission drive ratio, being adapted to move the transfer valve means to its second state upon movement of the detector valve means to its second state, whereby the feedline is pressurized if the output of the actuating means corresponds to normal operation in a drive ratio and whereby the failsafe line is pressurized if the output of the actuating means is other than the output required for normal operation.
Dependencies are inferred from the claim text.