| 摘要 |
PURPOSE: A method of controlling kickdown shift from three-stage into two-stage of an automatic transmission is provided to prevent double-speed change shock caused by actions of a front clutch, to improve durability of an automatic transmission, and to improve drivability. CONSTITUTION: A method of controlling kickdown shift from three-stage into two-stage of an automatic transmission comprises steps of deciding whether a speed change control signal to perform kickdown from 3-stage to 2-stage is output(S120); initializing all variables and deciding whether kickdown shift is off after passage of fill-time(S140); setting up initial duty, duty gradient, and duty output time according to the speed change pattern stored in a memory and outputting into a duty control signal(S150); deciding whether speed change synchronization into a target gear level is finished(S160); calculating duty value at the final duty value of the finish point of time of speed change synchronization and outputting new duty value(S170); and outputting the duty control signal while reducing the duty control signal during predetermined reference time at the gradient set up from the output duty value(S180).
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