Abnormality detection apparatus for power supply circuit

• US RE39,212 E1
• Filed: 10/08/2004
• Issued: 08/01/2006
• Est. Priority Date: 08/25/1999
• Status: Expired due to Fees

• Current Assignee: Toyota Jidosha Kabushiki Kaisha (Toyota Motor Corporation)
• Original Assignee: Toyota Jidosha Kabushiki Kaisha (Toyota Motor Corporation)
• Inventors: Yokoyama, Hidenori
• Primary Examiner(s): DEB, ANJAN K
• Application Number:
  US10/960,895
• Time in Patent Office: 662 Days
• Field of Search: 324/429, 324/426, 324/771, 324/431, 322/25, 320/136, 702/63, 340/455, 307/10.6, 307/10.7
• US Class Current: 324/429
• CPC Class Codes: F02N 11/0825 related to prevention of engine restart failure, e.g. disabling automatic stop at low battery state
• CPC Class Codes: F02N 11/0862 characterised by the electrical power supply means, e.g. battery
• CPC Class Codes: F02N 11/10 Safety devices F02N11/08 takes precedence
• CPC Class Codes: F02N 2200/062 Battery current
• CPC Class Codes: F02N 2200/063 Battery voltage
• CPC Class Codes: F02N 2200/064 Battery temperature
• CPC Class Codes: G01R 31/3647 for determining the ability of a battery to perform a critical function, e.g. cranking
• CPC Class Codes: H02J 7/1415 with a generator driven by a prime mover other than the motor of a vehicle
• CPC Class Codes: H02J 7/1461 with safety or indicationg devices
• CPC Class Codes: Y02T 10/48 Switching off the internal combustion engine, e.g. stop and go

Abstract

An abnormality detection apparatus for a power supply circuit associated with an internal combustion engine detects an abnormality that may occur in a power supply circuit, and controls the automatic stop and the automatic start of the engine based on the state of the power supply circuit. The state of charge/discharge of a battery determined based on the electric potential of a terminal located between the battery and a generator-motor or a load is compared with the current through the battery detected by an ammeter. If there is a contradiction therebetween, it is determined that an abnormality has occurred somewhere in the power supply circuit including the battery. When it is determined that the power supply circuit has an abnormality, the apparatus performs such a control as to prevent the automatic stop/start control in which the engine is automatically stopped if a predetermined condition is met, and in which the engine is automatically restarted when the condition is unmet after being met.

Claims

1. An abnormality detection apparatus for a power supply circuit having a chargeable battery connected to a generator, comprising:

a power supply circuit controller, which

determines a state of the generator;

determines a state of the battery; and

determines that the power supply circuit is normal when the generator is in a generating state and the battery is in a charged state or when the generator is in a non-generating state and the battery is in a discharged state.

2. An abnormality detection apparatus according to claim 1, further comprising a current detector that detects a current through the battery, wherein the power supply circuit controller detects an electric potential of at least a portion of a wiring connecting between the power supply circuit and at least one of the generator and a load, and the power supply circuit controller detects an abnormality of the power supply circuit based on the electric potential detected and the current detected by the current detector.

3. An abnormality detection apparatus according to claim 2, wherein the power supply circuit controller determines the state of the generator based on the electric potential detected.

4. An abnormality detection apparatus according to claim 3, wherein the power supply circuit controller determines that the generator is in a generation capable state when the electric potential detected is equal to a predetermined electric potential.

5. An abnormality detection apparatus according to claim 4, wherein the predetermined electric potential is determined based on an output electric potential set in the generator.

6. An abnormality detection apparatus according to claim 5, further comprising a temperature detector that detects a temperature of the battery, wherein the power supply circuit controller sets the predetermined electric potential based on the temperature detected by the temperature detector.

7. An abnormality detection apparatus for a power supply circuit according to claim 1, further comprising:

an engine controller for controlling an internal combustion engine,

wherein said engine controller automatically stops the internal combustion engine when a predetermined condition is met and automatically restarts the internal combustion engine when the predetermined condition is unmet after being met; and

wherein an automatic stop/restart of the internal combustion engine is prohibited when the power supply circuit controller determines that the power supply circuit has an abnormality.

8. An abnormality detection method for a power supply circuit having a chargeable battery connected to a generator, the method comprising:

determining a state of the generator;

determining a state of the battery; and

determining that the power supply circuit is normal when the generator is in a generating state and the battery is in a charged state or when the generator is in a non-generating state and the battery is in a discharged state.

9. A An abnormality detection method according to claim 8, further comprising:

detecting a current through the battery;

detecting an electric potential of at least a portion of a wiring connecting between the power supple circuit and at least one of the generator and a load; and

determining whether the power supply circuit has an abnormality based on the electric potential detected and the current detected by the current detector.

10. An abnormality detection method according to claim 9, wherein the state of the generator is determined based on the electric potential detected.

11. An abnormality detection method according to claim 10, wherein it is determined that the generator is in a generation capable state when the electric potential detected is equal to a predetermined electric potential.

12. An abnormality detection method according to claim 11, wherein the predetermined electric potential is determined based on an output electric potential set in the generator.

13. An abnormality detection method according to claim 12, further comprising:

detecting a temperature of the battery; and

changing the predetermined electric potential based on the temperature detected.