Shift control device of vehicular automatic transmission

A shift control device of a vehicular automatic transmission that establishes a plurality of gear steps of different speed change ratios by selectively engaging a plurality of friction engagement devices, and speed-changes rotation transferred from an engine to an input shaft, and outputs speed-changed rotation, in which if during a first shift in a power-off state, a second shift judgment for a second shift that is a power-on downshift is made, performs a second shift control of lower an input shaft rotation speed to a synchronous rotation speed of a post-second shift gear step through an engagement control of the friction engagement devices in order to execute the second shift, the shift control device comprising:

• a shift-time throttle controller that, when the second shift is performed, performs a control of reducing a throttle valve opening degree of the engine to a predetermined degree of opening that causes the engine to output a torque that is able to bring the input shaft rotation speed of the input shaft to a rotation speed that is higher than the synchronous rotation speed of the post-second shift gear step;
• and
• a shift-time ignition timing controller that executes a retardation control of retarding an ignition timing of the engine when the input shaft rotation speed is dropped through the second shift control;
• wherein the shift time ignition timing controller calculates a maximum value of the input shaft rotation speed during execution of the retardation control, and
• wherein the shift-time ignition timing controller judges whether or not the maximum value is less than a pre-determined switch determination speed that is higher than the synchronous rotation speed of the post-second shift gear step, and if it is judged that the maximum value is less than the switch determination speed, the shift-time ignition timing controller causes a return from the retardation control on a condition that the input shaft rotation speed is less than a first return rotation speed, and if it is judged that the maximum value is greater than or equal to the switch determination speed, the shift-time ignition timing controller causes the return from the retardation control on a condition that the input shaft rotation speed is less than a second return rotation speed that is higher than the first return rotation speed.