COASTING DOWNSHIFT CONTROL DEVICE FOR AUTOMATIC TRANSMISSION

摘要

When the torque converter is in the lock-up state to prolong the fuel cut time that results from the vehicle coasting with the accelerator pedal opening angle APO=0, a downshift command is generated at (t1). During downshifting of the automatic transmission by a reduction in the release side clutch oil pressure Poff and an increase in the engagement side clutch oil pressure Pon, the engagement side clutch oil pressure Pon is reduced from the high lock-up ON oil pressure, graphically represented by the dotted line, to the low lock-up OFF oil pressure as represented by the "C" section of the dot-dash line after (t2) when lock-up is predicted to be turned off. An increase in the sag on the transmission output torque at the inertia phase start time (t5) can thereby be prevented and the quality of gear shifting can be improved by reducing the variation width (D) of the subsequent vehicle deceleration (G) as represented by the dot-dash line.