Power output apparatus, vehicle equipped with power output apparatus, and control method of power output apparatus

1. A power output apparatus configured to output power to a driveshaft, the power output apparatus comprising:

an internal combustion engine;

a first motor constructed to input and output power;

a second motor constructed to input and output power;

an accumulator arranged to transmit electric power to and from each of the first motor and the second motor;

a power distribution integration mechanism configured to have a first element connecting with the rotating shaft of the first motor, a second element connecting with the rotating shaft of the second motor, and a third element connecting with an engine shaft of the internal combustion engine and arranged to allow mutually differential rotations of the three elements;

a connecting-disconnecting device configured to attain driving source element connection and release of the driving source element connection, the driving source element connection being any one of connection of the first motor with the first element, connection of the second motor with the second element, and connection of the internal combustion engine with the third element;

a speed change-transmission assembly configured to selectively connect either one or both of a rotating shaft of the first motor and a rotating shaft of the second motor to the driveshaft and transmit the output power from the first motor and the output power from the second motor to the driveshaft at preset speed ratios;

a power demand setting module configured to set a power demand as a power required for the driveshaft; and

a controller configured to control the first motor and the second motor so as to make a level of heat generation in the first motor substantially equivalent to a level of heat generation in the second motor and ensure output of a power equivalent to the set power demand to the driveshaft in a state that both of the first motor and the second motor are connected to the driveshaft by means of the speed change-transmission assembly, the driving source element connection is released by the connecting-disconnecting device and operation of the internal combustion engine is stopped.

2. The power output apparatus in accordance with claim 1 , wherein the controller sets target powers, which are to be output from the first motor and from the second motor, based on the set power demand, in order to minimize a total of a loss of the first motor and a loss of the second motor.

3. A motor vehicle equipped with drive wheels driven with power from a driveshaft, the motor vehicle comprising:

an internal combustion engine;

a first motor constructed to input and output power;

a second motor constructed to input and output power;

an accumulator arranged to transmit electric power to and from each of the first motor and the second motor;

a power distribution integration mechanism configured to have a first element connecting with the rotating shaft of the first motor, a second element connecting with the rotating shaft of the second motor, and a third element connecting with an engine shaft of the internal combustion engine and arranged to allow mutually differential rotations of the three elements;

a connecting-disconnecting device configured to attain driving source element connection and release of the driving source element connection, the driving source element connection being any one of connection of the first motor with the first element, connection of the second motor with the second element, and connection of the internal combustion engine with the third element;

a speed change-transmission assembly configured to selectively connect either one or both of a rotating shaft of the first motor and a rotating shaft of the second motor to the driveshaft and transmit the output power from the first motor and the output power from the second motor to the driveshaft at preset speed ratios;

a power demand setting module configured to set a power demand as a power required for the driveshaft; and

a controller configured to control the first motor and the second motor so as to make a level of heat generation in the first motor substantially equivalent to a level of heat generation in the second motor and ensure output of a power equivalent to the set power demand to the driveshaft in a state that both of the first motor and the second motor are connected to the driveshaft by means of the speed change-transmission assembly, the driving source element connection is released by the connecting-disconnecting device and operation of the internal combustion engine is stopped.

4. A control method of a power output apparatus, the power output apparatus including: a driveshaft; an internal combustion engine; a first motor and a second motor respectively constructed to input and output power; an accumulator arranged to transmit electric power to and from each of the first motor and the second motor; a power distribution integration mechanism configured to have a first element connecting with the rotating shaft of the first motor, a second element connecting with the rotating shaft of the second motor, and a third element connecting with an engine shaft of the internal combustion engine and arranged to allow mutually differential rotations of the three elements; a connecting-disconnecting device configured to attain driving source element connection and release of the driving source element connection, the driving source element connection being any one of connection of the first motor with the first element, connection of the second motor with the second element, and connection of the internal combustion engine with the third element; and a speed change-transmission assembly configured to selectively connect either one or both of a rotating shaft of the first motor and a rotating shaft of the second motor to the driveshaft and transmit the output power from the first motor and the output power from the second motor to the driveshaft at preset speed ratios, the control method comprising:

controlling the speed change-transmission assembly to connect both the first motor and the second motor to the driveshaft in a state that the driving source element connection is released by the connecting-disconnecting device and operation of the internal combustion engine is stopped; and

controlling the first motor and the second motor to make a level of heat generation in the first motor substantially equivalent to a level of heat generation in the second motor and to ensure output of a power, which is equivalent to a power demand as a power required for the driveshaft, to the driveshaft.

5. The control method of the power output apparatus in accordance with claim 4 , wherein the target powers, which are to be output from the first motor and from the second motor are set based on the power demand, in order to minimize a total of a loss of the first motor and a loss of the second motor.