Patent ID: 8251165

Claim:
A power output apparatus that outputs power to a drive shaft, the power output apparatus comprising: an internal combustion engine; a first motor configured to input and output power; a second motor configured to input and output power; an accumulator configured to supply and receive electric power from each of the first and second motors; a power distribution integration mechanism having a first element connected to a rotating shaft of the first motor, a second element connected to a rotating shaft of the second motor, and a third element connected to an engine shaft of the internal combustion engine, the power distribution integration mechanism configured to input or output power based on power input to or output from either two of the three elements to a residual element; a change speed transmission configured to selectively connect either one or both of the first and second elements of the power distribution integration mechanism with the drive shaft and to transmit power from the first element and power from the second element at respective speed ratios to the drive shaft; a power demand setting module configured to set a power demand required for the drive shaft; and a control module that controls the internal combustion engine, the first and second motors and the change speed transmission so as to ensure power equivalent to the set power demand; the control module disconnecting one of the first and second elements of the power distribution integration mechanism from the drive shaft and connecting the other of the first and second elements with the drive shaft while performing a rotational speed adjustment process, a connection the other of the first and second elements with the drive shaft by the change speed transmission, a power transfer process, and a disconnection the one of the first and second elements from the drive shaft, in response to a satisfaction of a predetermined change speed state shift condition while the change speed transmission connects the one of the first and second elements with the drive shaft, the internal combustion engine is operated and the first and second motors are driven and controlled; the rotational speed adjustment process being a process of adjusting the rotational speed of the first or second motor corresponding to the other of the first and second elements so as to enable the connection between the other of the first and second elements and the drive shaft; the power transfer process being a process of transferring power between the first and second motors while the change speed transmission connects both of the first and second elements with the drive shaft so as to make the first and second motors respectively output power required when only the other of the first and second elements is connected with the drive shaft.