Power output unit, method of controlling the power output unit, and hybrid vehicle

• US 6,356,817 B1
• Filed: 05/16/2000
• Issued: 03/12/2002
• Est. Priority Date: 05/18/1999
• Status: Expired due to Term

• Current Assignee: Toyota Jidosha Kabushiki Kaisha (Toyota Motor Corporation)
• Original Assignee: Toyota Jidosha Kabushiki Kaisha (Toyota Motor Corporation)
• Inventors: Abe, Tetsuya
• Primary Examiner(s): Cuchlinski, Jr., William A.
• Assistant Examiner(s): MARC-COLEMAN, MARTHE Y
• Application Number:
  US09/571,529
• Time in Patent Office: 665 Days
• Field of Search: 701/22, 290/40.A, 290/40.B, 290/40.C, 290/40.R, 290/38.R, 290/45, 290/46, 180/65.2, 318/8, 318/9, 318/34, 318/51, 318/52
• US Class Current: 701/22
• CPC Class Codes: B60K 1/02 comprising more than one electric motor
• CPC Class Codes: B60K 6/365 with the gears having orbital motion
• CPC Class Codes: B60K 6/445 Differential gearing distribution type
• CPC Class Codes: B60K 6/448 Electrical distribution type
• CPC Class Codes: B60L 2240/421 Speed
• CPC Class Codes: B60L 2240/423 Torque
• CPC Class Codes: B60L 50/15 with additional electric power supply with capacitors charged by engine-driven generators B60L50/40; with batteries charged by engine-driven generators B60L50/61
• CPC Class Codes: B60W 10/06 including control of combustion engines
• CPC Class Codes: B60W 10/08 including control of electric propulsion units, e.g. motors or generators
• CPC Class Codes: B60W 10/26 for electrical energy, e.g. batteries or capacitors
• CPC Class Codes: B60W 20/00 Control systems specially adapted for hybrid vehicles hybrid vehicle design, B60K6/00; electric vehicles B60L
• CPC Class Codes: B60W 20/10 Controlling the power contribution of each of the prime movers to meet required power demand
• CPC Class Codes: B60W 2510/081 Speed
• CPC Class Codes: B60W 2710/083 Torque
• CPC Class Codes: Y02T 10/40 Engine management systems
• CPC Class Codes: Y02T 10/62 Hybrid vehicles
• CPC Class Codes: Y02T 10/64 Electric machine technologies in electromobility
• CPC Class Codes: Y02T 10/7072 Electromobility specific charging systems or methods for batteries, ultracapacitors, supercapacitors or double-layer capacitors
• CPC Class Codes: Y10S 903/903 having energy storing means, e.g. battery, capacitor
• CPC Class Codes: Y10S 903/91 Orbital, e.g. planetary gears

Abstract

A power output unit of the present invention sufficiently ensures the performance of a vehicle by sufficiently developing the performance of an engine without enlarging a motor. In a hybrid vehicle, a power requirement for the engine is set based on a vehicle speed and an accelerator opening degree. Usually, while giving priority to efficiency, an operation state of the engine is set based on a power requirement. Once the operation state of the engine is set, operation states of first and second motors are set based on a vehicle speed and a drive force. If the thus-set operation state of the first or second motor exceeds a threshold value, the operation state of the first or second motor is set so as not to exceed the threshold value. Based on the setting result and the power requirement, an operation state of the engine is set.

Claims

1. A power output unit comprising:

an engine having an output shaft;

electric motors coupled to a drive shaft transmitting a power outputted from the engine through the output shaft to the outside;

a power adjuster which is coupled to the output shaft and the drive shaft and which adjusts a power from the output shaft by means of electric power to transmit the power to the drive shaft;

a power requirement calculator which calculates a power required for the engine;

a rotational speed judging device which detects a rotational speed of the drive shaft and which compares the rotational speed with a permissible rotational speed of the electric motors;

an operation state setting device, wherein the operating state setting device sets operation states of the electric motors such that when an operating limit of the electric motors is reached, the electric motors assume an output torque approximately equal to zero and a rotational speed equal to a rotational speed of the drive shaft, and further wherein the operating state setting device sets an operation state of the engine based on the set operation states of the electric motors and the power requirement; and

an operator which operates the engine, the power adjuster and the electric motors based on the operation state set by the operation state setting device.

2. A hybrid vehicle which has the power output unit according to claim 1 and which travels by means of a power outputted from the drive shaft.

3. The power output unit according to claim 1, wherein:

the power adjuster has a generator and a planetary gear having three rotational shafts;

the three rotational shafts are respectively coupled to the generator, the output shaft of the engine and the drive shaft.

4. A hybrid vehicle which has the power output unit according to claim 3 and which travels by means of a power outputted from the drive shaft.

5. The power output unit according to claim 1, wherein:

the power adjuster has a paired-rotor electric motor having two rotors which can rotate relative to each other.

6. A hybrid vehicle which has the power output unit according to claim 5 and which travels by means of a power outputted from the drive shaft.

7. The power output unit according to claim 1, further comprising:

a secondary battery which can exchange electric power with the power adjuster and with the electric motors; and

a balance calculator which calculates an energy balance at least based on an energy loss generated during transmission of the power from the engine to the drive shaft and on a requirement for charge and discharge in the secondary battery, wherein;

the operation state setting device corrects the power outputted from the engine by correcting a rotational speed of the engine based on the energy balance calculated by the balance calculator, when setting an operation state of the engine; and

the operator operates the engine and the power adjuster based on the power corrected by the operation state setting device.

8. A hybrid vehicle which has the power output unit according to claim 7 and which travels by means of a power outputted from the drive shaft.

9. A power output unit comprising:

an engine having an output shaft;

electric motors coupled to a drive shaft transmitting a power outputted from the engine through the output shaft to the outside;

a power adjuster which is coupled to the output shaft and the drive shaft and which adjusts a power from the output shaft by means of electric power to transmit the power to the drive shaft;

a power requirement calculator which calculates a power required for the engine;

a rotational speed judging device which detects a rotational speed of the drive shaft and which compares the rotational speed with a permissible rotational speed of the electric motors;

a torque setting device which sets an operation state of the engine based on the calculated power requirement and which sets output torque values of the electric motors based on the set operation state of the engine when the detected rotational speed is equal to or lower than the permissible rotational speed;

a torque judging device which compares the set output torque values of the electric motors with a predetermined amount;

an operation state setting device, wherein the operating state setting device sets operation states of the electric motors such that when an operating limit of the electric motors is reached, the electric motors assume an output torque approximately equal to zero and a rotational speed equal to a rotational speed of the drive shaft, and further wherein the operating state setting device sets an operation state of the engine based on the set operation states of the electric motors and the power requirement; and

an operator which operates the engine, the power adjuster and the electric motors based on the operation state set by the operation state setting device.

10. A hybrid vehicle which has the power output unit according to claim 9 and which travels by means of a power outputted from the drive shaft.

11. A method of controlling a power unit including:

an engine having an output shaft;

electric motors coupled to a drive shaft transmitting a power outputted from the engine through the output shaft to the outside;

a power adjuster which is coupled to the output shaft and the drive shaft and which adjusts a power from the output shaft by means of electric power to transmit the power to the drive shaft, comprising the steps of;

calculating a power required for the engine;

detecting a rotational speed of the drive shaft and comparing the rotational speed with a threshold value of a rotational speed that is permissible when the electric motors output power; and

setting operation states of the electric motors such that the electric motors assume an output torque approximately equal to zero and a rotational speed equal to a rotational speed of the drive shaft when the detected rotational speed is higher than an operating limit of the electric motors.