Engine Start Device

• US 20090050092A1
• Filed: 05/17/2006
• Published: 02/26/2009
• Est. Priority Date: 05/17/2005
• Status: Active Grant

• Current Assignee: Panasonic Corporation (Panasonic Holdings Corporation)
• Original Assignee: Panasonic Corporation (Panasonic Holdings Corporation)
• Inventors: Yoshida, Koji, Handa, Hiroyuki
• Granted Patent: US 8,210,145 B2
• Time in Patent Office: Days
• US Class Current: 123/179.300
• CPC Class Codes: F02N 11/04 the motors being associated with current generators
• CPC Class Codes: F02N 11/0866 comprising several power sources, e.g. battery and capacitor or two batteries
• CPC Class Codes: F02N 2011/0885 Capacitors, e.g. for additional power supply
• CPC Class Codes: F02N 2011/0888 DC/DC converters
• CPC Class Codes: F02N 2200/063 Battery voltage
• CPC Class Codes: H02J 7/345 using capacitors as storage or buffering devices
• CPC Class Codes: H02P 1/18 for starting an individual dc motor

Abstract

An engine start device includes a generator, a battery charged by the generator, a starter, an electric double layer capacitor and a DC/DC converter. The electric double layer capacitor is connected between the starter and the battery. The DC/DC converter has an input terminal connected to the battery and the electric double layer capacitor. The DC/DC converter has an output terminal connected to the starter and the electric double layer capacitor. According to voltage of the battery, internal DC resistance of the battery or internal DC resistance of the electric double layer capacitor, the DC/DC converter effects control of charge voltage of the electric double layer capacitor so as to stabilize voltage applied to a starter motor and stabilize the engine start.

Claims

1. An engine start device comprising:

a generator connected to a driving system of an engine;

a starter connected to the driving system of the engine;

a battery charged by the generator;

an electric double layer capacitor connected between the starter and the battery; and

a DC/DC converter including;

an input terminal connected to a junction point of the battery and the electric double layer capacitor; and

an output terminal connected to a junction point of the starter and the electric double layer capacitor.

2. The engine start device of claim 1 further comprising:

a diode connected between the starter and the battery in a manner that the diode has a parallel connection to the electric double layer capacitor.

3. The engine start device of claim 1, wherein the DC/DC converter is a two-way converter.

4. The engine start device of claim 1 further comprising:

a controller connected to the DC/DC converter,

wherein the controller controls a voltage for charging from the DC/DC converter to the electric double layer capacitor so that a constant voltage is applied to the starter.

5. The engine start device of claim 4, wherein the controller calculates an amount of voltage-drop from at least one of voltage of the battery internal DC resistance of the battery and internal DC resistance of the electric double layer capacitor, and determines charging voltage of the electric double layer capacitor.

6. The engine start device of claim 4, wherein the controller controls a voltage for charging from the DC/DC converter to the electric double layer capacitor so that the starter starts working with constant application voltage.

7. The engine start device of claim 5 further comprising:

a current-detecting means and a voltage-detecting means for detecting the internal DC resistance of the battery or the electric double layer capacitor.

8. The engine start device of claim 5, wherein the internal DC resistance of the battery or the internal DC resistance of the electric double layer capacitor is calculated from a voltage value of the battery or a voltage value of the electric double layer capacitor detected by the voltage-detecting means and a current value of the DC/DC converter in constant-current driving.

9. The engine start device of claim 6, wherein the engine start device detects voltage of the starter at start-up and determines charging voltage of the electric double layer capacitor according to the detected voltage.

10. The engine start device of claim 3, wherein the two-way converter transfers charges of the electric double layer capacitor to the battery in completion of operations of the engine.

11. The engine start device of claim 2, wherein when the voltage of the battery is lower than a predetermined voltage prior to an initial start of the engine, the DC/DC converter can charge the electric double layer capacitor before the initial start of the engine.

12. The engine start device of claim 2, wherein when an initial start of the engine is not succeeded, the DC/DC converter can charge the electric double layer capacitor prior to a following start of the engine.

13. The engine start device of claim 2, wherein the DC/DC converter is a two-way converter.

14. The engine start device of claim 2 further comprising:

a controller connected to the DC/DC converter,

wherein the controller controls a voltage for charging from the DC/DC converter to the electric double layer capacitor so that a constant voltage is applied to the starter.

15. The engine start device of claim 14, wherein the controller calculates an amount of voltage-drop from at least one of voltage of the battery internal DC resistance of the battery and internal DC resistance of the electric double layer capacitor, and determines charging voltage of the electric double layer capacitor.

16. The engine start device of claim 14, wherein the controller controls a voltage for charging from the DC/DC converter to the electric double layer capacitor so that the starter starts working with constant application voltage.

17. The engine start device of claim 15 further comprising:

a current-detecting means and a voltage-detecting means for detecting the internal DC resistance of the battery or the electric double layer capacitor.

18. The engine start device of claim 15, wherein the internal DC resistance of the battery or the internal DC resistance of the electric double layer capacitor is calculated from a voltage value of the battery or a voltage value of the electric double layer capacitor detected by the voltage-detecting means and a current value of the DC/DC converter in constant-current driving.

19. The engine start device of claim 16, wherein the engine start device detects voltage of the starter at start-up and determines charging voltage of the electric double layer capacitor according to the detected voltage.

20. The engine start device of claim 13, wherein the two-way converter transfers charges of the electric double layer capacitor to the battery in completion of operations of the engine.