Power output device and control method of the power output device and hybrid vehicle driven by the power output device

• US 6,208,034 B1
• Filed: 04/09/1999
• Issued: 03/27/2001
• Est. Priority Date: 07/13/1998
• Status: Expired due to Term

• Current Assignee: Toyota Jidosha Kabushiki Kaisha (Toyota Motor Corporation)
• Original Assignee: Toyota Jidosha Kabushiki Kaisha (Toyota Motor Corporation)
• Inventors: Yamaguchi, Katsuhiko
• Primary Examiner(s): Enad, Elvin
• Application Number:
  US09/288,657
• Time in Patent Office: 718 Days
• Field of Search: 290/40-A-
• US Class Current: 290/40.00C
• CPC Class Codes: B60K 6/365 with the gears having orbital motion
• CPC Class Codes: B60K 6/40 characterised by the assembly or relative disposition of components
• CPC Class Codes: B60K 6/445 Differential gearing distribution type
• CPC Class Codes: B60L 2240/423 Torque
• CPC Class Codes: B60L 50/61 by batteries charged by engine-driven generators, e.g. series hybrid electric vehicles
• 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 2050/001 Proportional integral [PI] controller
• CPC Class Codes: B60W 2710/0666 Engine torque
• CPC Class Codes: B60W 2710/083 Torque
• CPC Class Codes: Y02T 10/62 Hybrid vehicles
• CPC Class Codes: Y02T 10/64 Electric machine technologies in electromobility
• CPC Class Codes: Y02T 10/70 Energy storage systems for electromobility, e.g. batteries
• 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 903/905 Combustion engine
• CPC Class Codes: Y10S 903/906 Motor or generator
• CPC Class Codes: Y10S 903/91 Orbital, e.g. planetary gears
• CPC Class Codes: Y10S 903/951 : Assembly or relative location of components

Abstract

A power output device is provided with an internal combustion engine having an output shaft, an electric motor for generating and receiving electric power and for rotating a rotation shaft, a drive shaft mechanically connected to the output and the rotation shaft, and a battery for supplying electric power to the electric motor and storing electric power from the electric motor. When a vehicle mounting the power output device drives normally, a target torque of the motor is determined by the PI (Proportional Integral) control. When the vehicle drives with the engine stopping or idling, however, a target torque is determined to be substantially zero. Then an electric power for the control of the electric motor is prevented from being consumed. While such a control is executed, a target torque of the electric motor is determined by the PI control when the drive shaft is locked. Consequently, even when the drive shaft is locked, the rotation speed of the engine is kept to be substantially constant. Then such problems as a resonance and etc. of the power output device can be avoided and the vehicle drives stably.

Claims

1. A power output device comprising:

an internal combustion engine having an output shaft;

an electric motor for generating and receiving electric power and for rotating a rotation shaft;

a drive shaft mechanically connected to the output shaft of said internal combustion engine and the rotation shaft of said electric motor for rotating at the same rotation speed as or a different rotation speed from the output shaft;

a battery for supplying electric power to said electric motor and for storing electric power from said electric motor;

a torque determinater for determining output torque of said internal combustion engine and for relating the output torque to a requested power;

an electric motor controller that feedback-controls said electric motor so that the output power from said drive shaft is equal to the requested power; and

a second electric motor controller that controls said electric motor so that the output torque of said electric motor is substantially zero when the output torque of said internal combustion engine is substantially zero.

2. The power output device according to claim 1, further comprising a prevention determinater that determines whether or not an operating condition of said internal combustion engine should be avoided on the basis of the operating condition of said internal combustion engine, said electric motor and said drive shaft, wherein said second electric motor controller controls said electric motor so that the output torque of said electric motor is substantially zero when the output torque of said internal combustion engine is substantially zero and the operating condition of said internal combustion engine does not need to be avoided.

3. The power output device according to claim 2, wherein said prevention determinater includes rotation detecting means for detecting rotation speed of said drive shaft and prevention determining means for determining whether or not an operating condition of said internal combustion engine shouldbe avoided on the basis of the operation speed of said internal combustion engine.

4. The power output device according to claim 3, wherein said prevention determinater determines the operating condition of said internal combustion engine to be avoided until a predetermined time passes after the rotation speed of said internal combustion engine departs from the rotation speed to be avoided once the operating condition of said internal combustion engine is determined to be avoided.

5. The power output device according to claim 1, further comprising a planetary gear mechanically connecting together the output shaft of said internal combustion engine, the rotation shaft of said electric motor, and said drive shaft.

6. A control method for a power output device having an internal combustion engine with an output shaft, an electric motor for generating and receiving electric power and for rotating a rotation shaft, a drive shaft mechanically connected to the output shaft of said internal combustion engine and the rotation shaft of said electric motor for rotating at the same rotation speed as or a different rotation speed from the output shaft, and a battery for supplying electric power to said electric motor and for storing electric power from said electric motor, comprising:

determining output torque of said internal combustion engine and relating the output torque to a requested power;

feedback-controlling said electric motor so that the output power from said drive shaft is equal to the requested power; and

controlling said electric motor so that the output torque of said electric motor is substantially zero when the output torque of said internal combustion engine is substantially zero.

7. The control method of a power output device according to claim 6, further comprising:

detecting a parameter indicating the operating condition of said power output device;

determining whether or not an operating condition of said internal combustion engine should be avoided on the basis of said parameter;

controlling said electric motor so that the output torque of said electric motor is substantially zero when the output torque of said internal combustion engine is substantially zero and an operating condition of said internal combustion engine does not need to be avoided.

8. A hybrid vehicle with a wheel shaft driven by a power output device comprising:

an internal combustion engine having an output shaft;

an electric motor for generating and receiving electric power and for rotating a rotation shaft;

a drive shaft connected to said wheel shaft and mechanically connected to the output shaft of said internal combustion engine and the rotation shaft of said electric motor for rotating at the same rotation speed as or a different rotation speed from the output shaft;

a battery for supplying electric power to said electric motor and storing electric power from said electric motor;

a torque determinater for determining output torque of said internal combustion engine and for relating the output torque to a requested power;

an electric motor controller that feedback-controls said electric motor so that the output power from said drive shaft is equal to the requested power;

a lock determinater that determines whether said wheel shaft is locked or not; and

a second electric motor controller that controls said electric motor so that the output torque of said electric motor is substantially zero when the output torque of said internal combustion engine is substantially zero.

9. The hybrid vehicle with a wheel shaft driven by a power output device according to claim 8, further comprising a prevention determinater that determines whether or not an operating condition of said internal combustion engine should be avoided on the basis of the operating condition of said internal combustion engine, said electric motor and said drive shaft, wherein said second electric motor controller controls said electric motor so that the output torque of said electric motor is substantially zero when the output torque of said internal combustion engine is substantially zero and the operating condition of said internal combustion engine does not need to be avoided.