Power off upshift control method for automatic transmission

摘要

A power Off upshift control method for an automatic transmission includes the steps of: a) determining if a vehicle is under conditions requiring power Off upshift control; b) starting power Off upshift duty control if the conditions are satisfied; c) calculating average turbine rpm change rate; d) measuring turbine rpm changing period and determining if the turbine rpm changing period is greater than a predetermined value; e) calculating a shift finish point if the turbine rpm changing period is greater than the predetermined value; f) determining if the turbine rpm change rate is less than a value obtained by adding a mapping value to the turbine rpm change rate; g) determining if the turbine rpm value is greater than or equal to the shift finish point, if the turbine rpm change rate is greater than the mapped value in the previous step; h) producing a shift finish point duty rate if the turbine rpm value is greater than or equal to the shift finish point; i) determining if the turbine rpm is less than a target turbine rpm; j) ending duty control if the turbine rpm is less than the target turbine rpm; k) determining if the turbine rpm is less than the a value obtained by subtracting 100 rpm from the target turbine rpm; and l) compensating duty rate and learn the duty rate if the turbine rpm is less than the subtracted value in the previous step.