System for computer controlled shifting of an automatic transmission

Patent · Sat Dec 31 23:00:00 EST 1988

OSTI ID:866823

Patil, Prabhakar B ^[1]

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1. Detroit, MI

In an automotive vehicle having an automatic transmission that driveably connects a power source to the driving wheels, a method to control the application of hydraulic pressure to a clutch, whose engagement produces an upshift and whose disengagement produces a downshift, the speed of the power source, and the output torque of the transmission. The transmission output shaft torque and the power source speed are the controlled variables. The commanded power source torque and commanded hydraulic pressure supplied to the clutch are the control variables. A mathematical model is formulated that describes the kinematics and dynamics of the powertrain before, during and after a gear shift. The model represents the operating characteristics of each component and the structural arrangement of the components within the transmission being controlled. Next, a close loop feedback control is developed to determine the proper control law or compensation strategy to achieve an acceptably smooth gear ratio change, one in which the output torque disturbance is kept to a minimum and the duration of the shift is minimized. Then a computer algorithm simulating the shift dynamics employing the mathematical model is used to study the effects of changes in the values of the parameters established from a closed loop control of the clutch hydraulic and the power source torque on the shift quality. This computer simulation is used also to establish possible shift control strategies. The shift strategies determine from the prior step are reduced to an algorithm executed by a computer to control the operation of the power source and the transmission.

• Research Organization: FORD MOTOR CO
• DOE Contract Number: AC08-82NV10308
• Assignee: Ford Motor Company (Dearborn, MI)
• Patent Number(s): US 4799158
• OSTI ID: 866823
• Country of Publication: United States
• Language: English

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