Abstract: The power transmission has a fly-by-wire electro-hydraulic control mechanism that controls the engagement and disengagement of the range clutches in both forward and reverse operation. In forward operation, the control mechanism permits continued vehicle operation in the third forward range should electrical discontinuance occur during the first through fourth forward ranges, and in the fifth forward range should electrical discontinuance occur in the fifth or sixth forward range. Also, the control mechanism includes two logic valves and a forward on/off solenoid valve that permits the logic valves to control three torque-transmitting mechanisms with the use of two trim solenoid valves.

Abstract: The power transmission has a fly-by-wire electro-hydraulic control mechanism that controls the engagement and disengagement of the range clutches in both forward and reverse operation. In forward operation, the control mechanism permits continued vehicle operation in the third forward range should electrical discontinuance occur during the first through fourth forward ranges, and in the fifth forward range should electrical discontinuance occur in the fifth or sixth forward range. Also, the control mechanism includes two logic valves and a forward on/off solenoid valve that permits the logic valves to control three torque-transmitting mechanisms with the use of two trim solenoid valves.

Abstract: An improved and self-diagnosing shift pressure regulator apparatus for an automatic shift transmission provides a diagnostic output that reliably and timely detects initiation and cessation of fluid supply to a friction element. The regulator apparatus includes a pressure regulator valve responsive to an electronically developed pilot pressure, and a diagnostic switch. The pilot pressure positions the pressure regulator valve in one of three states—ON, TRIM, and OFF—and the diagnostic switch is continuously activated by a control pressure whenever the pressure regulator valve is in the TRIM or ON states.

Abstract: An improved control for an automatic transmission garage shift, wherein a dynamic model of the transmission is used to estimate the transmission input torque during the shift and to schedule the on-coming clutch pressure in accordance with the estimated input torque to achieve a desired input shaft trajectory. The transmission input torque is estimated based on two different methodologies —one suited to steady-state engine idle conditions, and the other suited to engine output torque transient conditions. A fuzzy summation of the input torques provided by the two methodologies is utilized in transitions between the two conditions. Shift quality variations due to variations in mechanical and/or hydraulic stiffness are minimized by a pause or hold interval inserted between the end of the fill period and the initiation of on-coming clutch pressure control, which results in a reasonably consistent degree of perceived transmission-to-transmission hydraulic and mechanical compliance.

Abstract: An improved shift control for a hydraulic automatic transmission in which the apply chamber of an on-coming clutch is filled in the preparation phase of the shift using a hydraulic flow rate model to estimate the volume of hydraulic fluid supplied to the apply chamber. In an initial portion of the fill interval, fluid is supplied to the apply chamber at a first elevated pressure, while continuously updating the fluid volume estimate. When the remaining un-filled volume of the apply chamber reaches a reference volume, the supply pressure is reduced to a second pressure at which the next phase of the shift is to be carried out. When the chamber volume is filled, the torque capacity of the clutch rises to a level corresponding to the second pressure, and the next phase of the shift automatically ensues.

Abstract: A control for a multi-speed transmission has a multiple gain trim valve that controls the engagement pressure rise in a selectively engageable torque transmitting mechanism. The trim valve has a valve spool and a plug valve longitudinally aligned in a valve bore such that four separate areas are present. One of the areas has the engagement pressure of the torque transmitting mechanism imposed thereon. Another of the areas has a control pressure imposed thereon and the remaining two areas are subjected to the trim pressure. The gain rate between the trim pressure and the engagement pressure determines the rapidity with which the torque transmitting mechanism is engaged. The control pressure reduces the effect of the trim pressure to provide a low gain rate until the product of the trim pressure and one of the areas is equal to or greater than the product of the control pressure and the area on which it operates.

Abstract: A pressure control valve system for a friction device has a regulator valve with a plurality of pressure feedback differential areas which are selectively pressurized during the engagement of a friction device to control the apply pressure at one rate during normal operation and at a higher rate during high torque demand operation. A plug valve is disposed adjacent the regulator valve to establish two variable control forces acting on the regulator valve in response to a variable control pressure. The combination of the differential areas and the plug valve permit the regulator valve to establish two distinct pressure gain functions, each of which has a knee or inflection point resulting in two pressure gain ratios.

Abstract: A rotating clutch has a feed passage that is maintained at a predetermined pressure by a backfill control valve during periods of clutch disengagement when the clutch apply chamber is not pressurized. The valve is slidably disposed in a stationary housing in fluid communication between a pressure source and the apply chamber of the clutch. When the pressure source is reduced below a predetermined level, the valve is positioned to prevent the pressure in the passage from decreasing below the predetermined level while exhausting the clutch apply chamber. When clutch actuation is desired, the pressure source increases to open the backfill valve. With the valve opened by pressure, the fluid pressure is supplied to the clutch apply chamber thereby applying the clutch. The valve is positioned in the housing to admit pressurized fluid from the source to the clutch apply chamber while disconnecting the apply chamber from exhaust when clutch apply is required.

Abstract: A hydraulic control for a transmission has a main line regulator, a torque converter clutch relay valve and a torque converter clutch solenoid valve. During torque converter operation, the pressure regulator is subjected to a line pressure bias signal and supplies pressurized hydraulic fluid to a control system at a substantially constant pressure level. During torque converter clutch operation, the pressure regulator is subjected to an additional line pressure bias signal and a variable pressure bias signal from the torque converter clutch solenoid valve to provide a modulated pressure control whereby main pressure is varied proportionally with torque converter clutch apply pressure.

Abstract: A system to control the operation of a vehicular transmission embodying the concepts of the present invention utilizes a controller, at least one pulse width modulation solenoid valve and a torque transfer device operatively controlled by each of the solenoid valves so as to regulate a transmission system. The controller operatively imposes not only a varying modulation frequency on each of the solenoid valves, but also a varying modulation duty cycle on each of the solenoid valves. The controller also operatively varies the modulation rate of said frequency and said duty cycle of the fluid pressure operating the plurality of torque transfer devices, thus controlling the operation of each solenoid valve such that it does not impose a torque spike on the operation of the transmission as each solenoid valve applies fluid pressure to the appropriate torque transfer device. Accordingly, the controller provides smooth and quiet operation of the transmission.