Engine control apparatus, control method and control system

• US 7,533,746 B2
• Filed: 08/04/2006
• Issued: 05/19/2009
• Est. Priority Date: 08/05/2005
• Status: Active Grant

• Current Assignee: Fujitsu Ten Limited (DENSO Corporation)
• Original Assignee: Fujitsu Ten Limited (DENSO Corporation)
• Inventors: Yamaguchi, Kazuhi
• Primary Examiner(s): Restifo; Jeffrey J
• Application Number:
  US11/498,909
• Publication Number:
  US 20070032915A1
• Time in Patent Office: 1,019 Days
• Field of Search: 180/65.2, 180/65.3, 180/65.4, 180/65.8, 903/941, 903/943
• US Class Current: 180/65.29
• CPC Class Codes: F02N 11/0814 comprising means for controlling automatic idle-start-stop
• CPC Class Codes: F02N 11/0866 comprising several power sources, e.g. battery and capacitor or two batteries
• CPC Class Codes: H02J 7/1423 with multiple batteries
• CPC Class Codes: Y02T 10/70 Energy storage systems for electromobility, e.g. batteries

Abstract

A first buttery supplies power to an electrical load of a vehicle when an engine is in a normal operation. A second buttery supplies power to the electrical load of the vehicle when the engine is in an economical operation. A voltage regulator regulates voltages of the first buttery and the second buttery. A current limiter limits a current value flowing from the voltage regulator to the second battery to a limiting value. An engine stopping unit stops the engine when a first predetermined condition is established. An activator starts the engine when a second predetermined condition is established. A current detecting unit detects the current value when a second battery is charged. A changing unit changes a limiting value between a first limiting value and a second limiting value which is higher than the first limiting value according to the detected current value in a case where the voltage of the second battery is no more than a second predetermined value and the voltage of the first battery is no less than a first predetermined value.

Claims

1. An engine control apparatus adapted to be mounted on a vehicle including:

a first battery, supplying power to an electrical load of the vehicle when an engine is in a normal operation;

a second battery, supplying power to the electrical load of the vehicle when the engine is in an economical operation;

a voltage regulator regulating voltages of the first battery and the second battery; and

a current limiter, incorporated in the voltage regulator and limiting a current value flowing from the voltage regulator to the second battery to a limiting value, the engine control apparatus comprising;

an engine stopping unit, stopping the engine when a first predetermined condition is established;

an engine starting unit, starting the engine when a second predetermined condition is established;

a current detecting unit, detecting the current value when the second battery is charged; and

a changing unit, changing the limiting value between a first limiting value and a second limiting value which is higher than the first limiting value according to the detected current value in a case where the voltage of the second battery is no more than a second predetermined value and the voltage of the first battery is no less than a first predetermined value.

2. The engine control apparatus as set forth in claim 1, further comprising:

a voltage detecting unit, detecting the voltages of the first battery and the second battery; and

switching unit, switching a target voltage value of the second battery from a first voltage value to a second voltage value which is higher than the first voltage value in a case where the voltage of the second battery is no more than a second predetermined value and the voltage of the first battery is no less than a first predetermined value.

3. The engine control apparatus as set forth in claim 2,

wherein the changing unit changes the limiting value to the second limiting value in a case where the current value is equal to the first limiting value in a predetermined time.

4. The engine control apparatus as set forth in claim 2,

wherein the changing unit changes the limiting value to the first limiting vale in a case where the current value is less than the first limiting value in a predetermined time.

5. The engine control apparatus as set forth in claim 2,

wherein the second battery is charged when the engine is idled.

6. The engine control apparatus as set forth in claim 2,

wherein the second battery is charged when the engine is in the normal operation.

7. The engine control apparatus as set forth in claim 2,

wherein the changing unit changes the limiting value to the first limiting value in a case where the voltage of the second battery is charged to a third voltage value which is lower than the first voltage value.

8. The engine control apparatus as set forth in claim 2, further comprising a calculating unit, calculating a differential voltage between the first voltage value and the voltage of the second battery,

wherein the switching unit switches the target voltage value from the second voltage value to the first voltage value in a case where the differential voltage is lower than a forth voltage value.

9. The engine control apparatus as set forth in claim 8,

wherein the switching unit switches the target voltage value from the second voltage value to the first voltage value in a case where the voltage of the first battery is no more than a sixth voltage value.

10. The engine control apparatus as set forth in claim 8, further comprising a prohibiting unit, prohibiting switching the target voltage value from the second voltage value to the first voltage value until the first battery is charged with a voltage corresponding to one of a discharged current value discharged from the first battery when the second battery is charged or a voltage drop when the second battery is charged in a case where the second battery is continuously charged after the switching unit switches the target voltage value from the second voltage value to the first voltage value.

11. The engine control apparatus as set forth in claim 8, further comprising:

a second calculating unit, calculating a second differential voltage between the first voltage value and the voltage of the second battery at the time of filling a condition where the switching unit switches the target voltage value from the second voltage value to the first voltage value;

an integrating unit, integrating the second differential voltage calculated by the second calculating unit;

a correcting unit, multiplying the second differential voltage and a integrated value integrated by the integrating unit by a correction coefficient respectively and correcting the first voltage value by adding a multiplied value multiplied by the correcting unit; and

a control unit, controlling the voltage of the second battery so as to converge on the first voltage value.

12. The engine control apparatus as set forth in claim 11, further comprising a judging unit, judging whether the second differential voltage is no more than a third threshold value or not,

wherein the correcting unit switches the correction coefficient in a case where it is judged by the judging unit that the second differential voltage is no more than the third threshold value.

13. The engine control apparatus as set forth in claim 11, further comprising a judging unit, judging whether the second differential voltage is no more than a fourth threshold value or not,

wherein the integrating unit clears the integrated value at the time of the second differential voltage being no more than a fourth threshold value,

wherein the control unit controls the voltage of the second battery so as to converge on the first voltage value.

14. The engine control apparatus as set forth in claim 11,

wherein the correcting unit determines whether a correction processing of the first voltage of the second battery is performed or not according to whether the second battery is charged or not.

15. The engine control apparatus as set forth in claim 2, further comprising a calculating unit, calculating a differential voltage between the voltage of the first battery before a charging control of the second battery is performed and the voltage of the first battery when the charging control of the second battery is performed,

wherein the switching unit switches the target voltage value from the second voltage value to the first voltage value in a case where the differential voltage is lower than a fifth voltage value.

16. The engine control apparatus as set forth in claim 15, further comprising an integrating unit, integrating a discharge current value of the first battery when the charging control of the second battery is performed,

wherein the switching unit switches the target voltage value from the second voltage value to the first voltage value in a case where the differential voltage is lower than a fifth voltage value and a integrated value integrated by the integrating unit is no less than a first threshold value.

17. The engine control apparatus as set forth in claim 2, further comprising an integrating unit, integrating a discharged current value of the first battery when the charging control of the second battery is performed,

wherein the switching unit switches the target voltage value from the second voltage value to the first voltage value in a case where a integrated value integrated by the integrating unit is no less than a first threshold value.

18. The engine control apparatus as set forth in claim 2,

wherein the changing unit changes the limiting value to the second limiting value in a case where the switching unit switches the target voltage value from the second voltage value to the first voltage value.

19. An engine control apparatus adapted to be mounted on a vehicle including:

a first battery, supplying power to an electrical load of the vehicle when an engine is in a normal operation;

a second battery, supplying power to the electrical load of the vehicle when the engine is in an economical operation; and

a voltage regulator, regulating voltages of the first battery and the second battery;

the engine control apparatus comprising;

a voltage detecting unit, detecting the voltages of the first battery and the second battery; and

switching unit, switching a target voltage value of the second battery from a first voltage value to a second voltage value which is higher than the first voltage value when the second battery is charged in a case where the voltage of the second battery is no more than a second predetermined value and the voltage of the first battery is no less than a first predetermined value.

20. An engine control method for an vehicle adapted to include;

a first battery, supplying power to an electrical load of the vehicle when an engine is in a normal operation;

a second battery, supplying power to the electrical load of the vehicle when the engine is in an economical operation;

a voltage regulator regulating voltages of the first battery and the second battery; and

a current limiter, incorporated in the voltage regulator and limiting a current value flowing from the voltage regulator to the second battery to a limiting value, the engine control method comprising;

stopping the engine when a first predetermined condition is established;

starting the engine when a second predetermined condition is established;

detecting the current value when the second battery is charged; and

changing the limiting value between a first limiting value and a second limiting value which is higher than the first limiting value according to the detected current value in a case where the voltage of the second battery is no more than a second predetermined value and the voltage of the first battery is no less than a first predetermined value.

21. An engine control system adapted to be mounted on a vehicle including:

a first battery, supplying power to an electrical load of the vehicle when an engine is in a normal operation;

a second battery, supplying power to the electrical load of the vehicle when the engine is in an economical operation;

a voltage regulator regulating voltages of the first battery and the second battery; and

a current limiter, incorporated in the voltage regulator and limiting a current value flowing from the voltage regulator to the second battery to a limiting value, the engine control apparatus comprising;

an engine stopping unit, stopping the engine when a first predetermined condition is established;

an activator, starting the engine when a second predetermined condition is established;

a current detecting unit, detecting the current value when the second battery is charged; and

a changing unit, changing the limiting value between a first limiting value and a second limiting value which is higher than the first limiting value according to the detected current value in a case where the voltage of the second battery is no more than a second predetermined value and the voltage of the first battery is no less than a first predetermined value.

22. An engine control apparatus automatically activating and deactivating an engine, and adapted to be mounted on a vehicle including:

a first battery, which is used when the engine is in a normal operation;

a second battery, which is used when the engine is automatically deactivated; and

a voltage regulator, performing a charge control of the second battery and limiting a current value flowing from the voltage regulator to the second battery to a limiting value, the engine control apparatus comprising;

a controller, operable to increase a target charge voltage value more than usual, and changing the limiting value between a first limiting value and a second limiting value which is higher than the first limiting value according to the current value in a case where a voltage of the first battery and a voltage of the second battery have a predetermined relation when the second battery is charged.