Controlling gear shifts in an automatic transmission.

摘要

A system for scheduling gear ratio changes in an automatic transmission and controlling operation of a torque converter bypass clutch (98) includes a microprocessor (60); electronic memory (62) containing control algorithms, lookup tables, functions and constants; solenoid-operated shift valves (70,72,74), a variable force solenoid (76), friction clutches, brakes and sensors (80), and planetary gear units. A table of calibrated performance weighting factors (PWF) is used to alter reference schedules of gear ratio changes based on the extent to which high performance operation is desired rather than economy operation. The PWFs are used to adjust gear shift points based on inferences drawn from engine throttle position and time rate of change of throttle position. Hydraulic pressure supplied to the friction elements and the schedule of unlocked and modulated operation of the torque converter (100) are adjusted from reference schedules and pressures on the basis of PWF values.