Lock-up control apparatus for automatic transmission

A lock-up control apparatus for an automatic transmission which inputs power via a lock-up clutch, and performs shifting by operations of a first through a fourth engagement elements when shifting is performed from the first shift speed to the second shift speed,

• and which continuously performs a shift control of a previous phase in which the first engagement element is disengaged and the third engagement element is engaged, and a shift control of a subsequent phase in which the second engagement element is disengaged and the fourth engagement element is engaged when shifting is performed from the first shift speed to the second shift speed, comprising:
• a lock-up control unit that performs a control for preventing reengagement of a lock-up clutch at a completion of shifting of the previous phase, the lock-up clutch having been brought into one of a disengagement state and a slip state at a start of shifting when shifting is performed from the first shift speed to the second shift speed during lock up.

A lock-up control method for an automatic transmission in which operations of four engagement elements are required when shifting is performed from a first shift speed to a second shift speed, the first shift speed being achieved by engaging a first engagement element and a second engagement element, the second shift speed being achieved by engaging a third engagement element and a fourth engagement element, the method comprising:

• performing a control to bring a lock-up clutch into one of a disengagement state and a slip state at a start of shifting, and to prevent reengagement of the lock-up clutch at a completion of engagement of the third engagement element when shifting is performed from the first shift speed to the second shift speed during lock up.

A lock-up control method for an automatic transmission which inputs power via a lock-up clutch, and performs shifting by operations of a first through a fourth engagement elements when shifting is performed from the first shift speed to the second shift speed, and which continuously performs a shift control of a previous phase in which the first engagement element is disengaged and the third engagement element is engaged, and a shift control of a subsequent phase in which the second engagement element is disengaged and the fourth engagement element is engaged when shifting is performed from the first shift speed to the second shift speed, the method comprising:

• performing a control to prevent reengagement of a lock-up clutch at a completion of shifting of the previous phase, the lock-up clutch having been brought into one of a disengagement state and a slip state at a start of shifting when shifting is performed from the first shift speed to the second shift speed during lock up.