System for starting an electric drive machine engine

• US 7,122,914 B2
• Filed: 12/22/2003
• Issued: 10/17/2006
• Est. Priority Date: 12/22/2003
• Status: Expired due to Fees

• Current Assignee: Caterpillar Incorporated
• Original Assignee: Caterpillar Incorporated
• Inventors: Caruthers, Michael Aaron
• Primary Examiner(s): Schuberg, Darren
• Assistant Examiner(s): Mohandesi, Iraj A.
• Application Number:
  US10/740,611
• Publication Number:
  US 20050134049A1
• Time in Patent Office: 1,030 Days
• Field of Search: 290/40.C, 290/40.A, 290/40.B, 290/40.R, 180/65.2
• US Class Current: 290/40.00C
• CPC Class Codes: F02D 2041/2003 using means for creating a boost voltage, i.e. generation or use of a voltage higher than the battery voltage, e.g. to speed up injector opening
• CPC Class Codes: F02D 2041/2017 using means for creating a boost current or using reference switching
• CPC Class Codes: F02N 11/04 the motors being associated with current generators

Abstract

A method for starting an engine of an electric drive machine may include the method steps of introducing current to an electric motor system from a battery and receiving the current into at least one coil on an electric motor of the electric motor system. The electric motor may be configured to drive the electric drive machine when operating. The method may also include the steps of releasing the energy from the at least one coil to an energy storage device and discharging the voltage from the energy storage device to a power generation system to start the engine. A system for starting an engine of an electric drive machine is also disclosed.

Claims

1. A method for starting an engine of an electric drive machine, comprising:

introducing current to an electric motor system from a battery;

receiving the current into at least one coil on an electric motor of the electric motor system, the electric motor being configured to drive the electric drive machine when operating,

using a controller to control releasing the energy from the at least one coil to an energy storage device; and

using the controller to control discharging the voltage from the energy storage device to a power generation system to start the engine.

2. The method of claim 1, further including accumulating energy from the at least one coil in the energy storage device.

3. The method of claim 2, further including repeating the receiving and releasing steps until the accumulated voltage in the energy storage device is at a level sufficient to start the engine.

4. The method of claim 1, further including operating switching elements in the electric motor system to direct current to the at least one coil and to release the energy from the at least one coil.

5. The method of claim 1, wherein the at least one coil is a stator winding in the electric motor.

6. The method of claim 1, further including storing the current from the battery in the at least one coil to increase an energy level in the at least one coil.

7. The method of claim 6, further including directing the energy from the at least one coil to the energy storage device through switching elements in a motor converter of the electric motor system.

8. The method of claim 1, wherein discharging the voltage from the energy storage device includes directing the voltage through switching elements in a generator converter of the power generation system.

9. A system for starting an engine of an electric drive machine, comprising:

a power generation system;

an electric motor system including an electric motor having at least one coil and configured to drive the electric drive machine when operating, the electric motor system being electrically associated with the power generation system;

a battery selectively associated with the electric motor system and configured to introduce current to the electric motor system; and

a controller configured to control the release of energy from the at least one coil in the electric motor to an energy storage device and configured to control the discharge of voltage from the energy storage device to the power generation system to start the engine.

10. The system of claim 9, wherein the energy storage device is configured to accumulate energy from the at least one coil to a level sufficient to start the engine.

11. The system of claim 9, further including switching elements in the electric motor system, wherein the controller is configured to operate the switching elements to direct current to the at least one coil and to release the energy from the at least one coil.

12. The system of claim 11, wherein the switching elements are one of IGBT and MOSFET switches.

13. The system of claim 9, wherein the at least one coil is a stator winding in the electric motor.

14. The system of claim 9, wherein the energy storage device is configured to accumulate energy released from the at least one coil, and store the accumulated energy until the energy level is high enough to start the engine.

15. The system of claim 14, wherein the power generation system includes:

a generator; and

a generator converter having switching elements operable to receive voltage from the energy storage device, the generator converter being configured to provide the voltage to the generator to start the engine.

16. The system of claim 9, wherein the electric motor system includes switching elements in a motor converter, the switching elements being configured to activate the accumulation of current in the at least one coil, and configured to activate the release of energy to the energy storage device.

17. The system of claim 16, wherein the controller is configured to modulate the switching elements to accumulate the energy in the at least one coil and release the energy to the energy storage device.

18. An electric drive machine, comprising:

an engine;

a generator associated with the engine and configured to generate power when driven by the engine and to turn the engine to start the engine when the engine is shut down;

a generator converter associated with the generator;

an electric motor converter associated with the generator converter;

an electric motor associated with the electric motor converter, the electric motor having at least one stator winding configured to operate as a coil, the electric motor being configured to drive the electric drive machine when operating;

a battery selectively associated with the electric motor converter and configured to introduce current to the at least one stator winding of the electric motor;

an energy storage device electrically disposed between the generator converter and the electric motor converter; and

a controller configured to control the release of energy from the at least one stator winding in the electric motor to the energy storage device and configured to control the discharge of voltage from the energy storage device to the generator converter to turn the generator and start the engine.

19. The electric drive machine of claim 18, wherein the energy storage device is configured to accumulate energy from the at least one stator winding to a level sufficient to start the engine.

20. The electric drive machine of claim 18, further including switching elements in the electric motor converter, wherein the controller is configured to operate the switching elements to direct current to the at least one stator winding and to release the energy from the at least one stator winding.

21. The electric drive machine of claim 20, wherein the controller is configured to modulate the switching elements to accumulate energy in the at least one stator winding and release the energy to the energy storage device.