Power unit for automobile

• US 7,407,025 B2
• Filed: 09/18/2003
• Issued: 08/05/2008
• Est. Priority Date: 12/16/2002
• Status: Expired due to Fees

• Current Assignee: Mitsubishi Denki Kabushiki Kaisha (Mitsubishi Electric Corporation)
• Original Assignee: Mitsubishi Denki Kabushiki Kaisha (Mitsubishi Electric Corporation)
• Inventors: Okuda, Tatsuya, Tsunoda, Yoshikazu, Urakabe, Takahiro
• Primary Examiner(s): Ellis; Christopher
• Assistant Examiner(s): SWENSON, BRIAN L
• Application Number:
  US10/538,653
• Publication Number:
  US 20060048983A1
• Time in Patent Office: 1,783 Days
• Field of Search: 180/65.1, 180/65.3, 180/65.4
• US Class Current: 180/65.1
• 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 11/10 Safety devices F02N11/08 takes precedence
• CPC Class Codes: F02N 2011/0888 DC/DC converters
• CPC Class Codes: H02J 7/345 using capacitors as storage or buffering devices
• CPC Class Codes: Y02T 10/7072 Electromobility specific charging systems or methods for batteries, ultracapacitors, supercapacitors or double-layer capacitors

Abstract

This invention provides a power unit for an automobile including a motor 6 for starting an engine by transmitting a power thereto and generating a power by receiving a power from the engine during rotation thereof, a power converting circuit 5 for transmitting a power to the motor 6, a battery 1, an energy storing source 20 for storing energy, and a DC/DC converter including at least two switching elements 10, 11, charging the energy storing source 20, and recovering energy in the energy storing source 20 to the battery 1. Since the switch provided in the DC/DC converter is normally turned on when the motor 6 generates power by receiving a power from the engine and charges the battery 1 through the power converting circuit 5 and the DC/DC converter, generation of heat from the DC/DC converter circuit part can be suppressed greatly.

Claims

1. An automobile power unit comprising:

an engine;

a motor that transmits a dynamic force to the engine and starts the engine, and

that receives a dynamic force of the engine during rotation of the engine and generates a power;

a power conversion circuit that has at least two DC voltage input/output terminals and transmits a power to the motor;

a battery that is connected to the power conversion circuit;

an energy storage source that is connected in series to the battery and stores energy; and

a DC/DC converter that is composed of at least two switching elements, that

charges the energy storage source by boosting a voltage of the energy storage source,

and that recovers energy in the energy storage source to the battery by lowering a voltage of the energy storage source,

wherein the switching elements of the DC/DC converter connect a high-voltage-side of the DC voltage input/output terminal of the power conversion circuit to a high-voltage-side terminal of the battery;

wherein when the motor receives a dynamic force of the engine, generates a power, and charges the battery through the power conversion circuit and the DC/DC converter, the switching elements provided in the DC/DC converter are constantly turned on; and

wherein after the engine has been started by the motor and before the power generation is carried out, the DC/DC converter operates the energy storage source in a voltage-lowerihg manner and recovers energy stored in the energy storage source to the battery.

2. The automobile power unit according to claim 1, wherein the energy storage source is charged during stop, pre-stop idling, or deceleration of the vehicle.

3. The automobile power unit according to claim 1, wherein each of the switching elements of the DC/DC converter is constituted by a semiconductor element.

4. The automobile power unit according to claim 1, wherein each of the switching elements of the DC/DC converter is constituted by a parallel circuit composed of a semiconductor element and a mechanical switch.

5. The automobile power unit according to claim 1, wherein the energy storage source is charged from the battery via the DC/DC converter before the engine is started by the motor.

6. The automobile power unit according to claim 1, wherein the switching element of the DC/DC converter is constituted by a mechanical switch.

7. An automobile power unit comprising:

an engine;

a motor that transmits a dynamic force to the engine and starts the engine, and that receives a dynamic force of the engine during rotation of the engine and generates a power;

a power conversion circuit that has at least two DC voltage input/output terminals and transmits a power to the motor;

a battery that is connected to the power conversion circuit;

an energy storage source that is connected in series to the battery and stores energy;

a DC/DC converter that comprises at least two switching elements, that changes the energy storage source by boosting a voltage of the energy storage source; and

a switch connected between a high-voltage-side terminal of the energy storage source and a high-voltage-side of the DC voltage input/output terminal of the power conversion circuit,

wherein the switching elements of the DC/DC converter connect the high-voltage-side of the DC voltage input/output terminal of the power conversion circuit to a high-voltage-side terminal of the battery, and

wherein when the motor receives a dynamic force of the engine, generates a power, and charges the battery through the power conversion circuit and the DC/DC converter, the switching elements provided in the DC/DC converter are constantly turned on and the switch is turned off.

8. The automobile power unit according to claim 7, wherein the energy storage source is charged during stop, pre-stop idling, or deceleration of the vehicle.

9. The automobile power unit according to claim 7, wherein each of the switching elements of the DC/DC converter is constituted by a semiconductor element.

10. The automobile power unit according to claim 7, wherein each of the switching elements of the DC/DC converter is constituted by a parallel circuit composed of a semiconductor element and a mechanical switch.

11. The automobile power unit according to claim 7, wherein the energy storage source is charged from the battery via the DC/DC converter before the engine is started by the motor.

12. The automobile power unit according to claim 7,

wherein energy is supplied from the battery to the power conversion circuit in a first half of a time period in which the engine is started by the motor, and

wherein energy is supplied from the battery and the energy storage source to the power conversion circuit in a second half of the time period.

13. The automobile power unit according to claim 7, wherein the switch connected between the high-voltage-side terminal of the energy storage source and the high-voltage-side of the DC voltage input/output terminal of the power conversion circuit is constituted by a semiconductor element.

14. The automobile power unit according to claim 7, wherein the switching element of the DC/DC converter is constituted by a mechanical switch.

15. The automobile power unit according to claim 7, wherein the switch connected between the high-voltage-side terminal of the energy storage source and the high-voltage-side of the DC voltage input/output terminal of the power conversion circuit is constituted by a mechanical switch.

16. An automobile power unit according to claim 7,

wherein the DC/DC converter further comprises a diode, and

wherein the diode is disposed in parallel with the switching elements of the DC/DC converter for use when the DC/DC converter charges the energy storage source by boosting a voltage of the energy storage source.

17. The automobile power unit according to claim 7, wherein each of the switching elements of the DC/DC converter is constituted by a semiconductor element.

18. The automobile power unit according to claim 7, wherein each of the switching elements of the DC/DC converter is constituted by a mechanical switch.

19. The automobile power unit according to claim 7, wherein the switch is constituted by a semiconductor element.

20. The automobile power unit according to claim 7, wherein the switch is constituted by a mechanical switch.