In a shift control system for an automatic transmission, shelf-pressure control
means include means for increasing the engagement pressure of the friction elements
at a first gradient as previously set after output of the shift command, wherein
after output of the shift command and when start of the inertia phase is detected,
a torque-reduction command is output to the torque-reduction control means, the
engagement pressure at detection of the inertia phase is set as an initial shelf
pressure to increase the shelf pressure at a second gradient set for each speed,
and a torque variation part oil pressure is added only when detecting a variation
in throttle opening, and wherein after start of the inertia phase and when completion
of the inertia phase is detected, a torque-reduction completion command is output
to the torque-reduction control means.
With this, the shelf pressure can be set appropriately during inertia phase
without needing an enormous data amount even if a variation in throttle opening
is present.
