Fiber laser coupled optical spark delivery system

• US 20060032471A1
• Filed: 08/04/2005
• Published: 02/16/2006
• Est. Priority Date: 08/04/2004
• Status: Active Grant

• Current Assignee: Colorado State University Research Foundation
• Original Assignee: Colorado State University Research Foundation
• Inventors: Joshi, Sachin, Yalin, Azer, Defoort, Morgan, Reynolds, Adam, Willson, Bryan
• Granted Patent: US 7,340,129 B2
• Time in Patent Office: Days
• US Class Current: 123/143.B
• CPC Class Codes: F02P 23/04 Other physical ignition means, e.g. using laser rays

Abstract

A spark delivery system for generating a spark using a laser beam is provided, and includes a laser light source and a laser delivery assembly. The laser delivery assembly includes a hollow fiber and a launch assembly comprising launch focusing optics to input the laser beam in the hollow fiber. The laser delivery assembly further includes exit focusing optics that demagnify an exit beam of laser light from the hollow fiber, thereby increasing the intensity of the laser beam and creating a spark. Other embodiments use a fiber laser to generate a spark. Embodiments of the present invention may be used to create a spark in an engine. Yet other embodiments include collecting light from the spark or a flame resulting from the spark and conveying the light for diagnostics. Methods of using the spark delivery systems and diagnostic systems are provided.

Claims

1. A system for generating a spark, comprising:

a fiber laser for generating a laser beam, wherein said laser beam exits said fiber laser at a fiber exit as an exit beam of laser light; and

exit optics operatively associated with a spark plug interconnected to a combustion engine at a spark plug well, said exit optics for receiving said exit beam of laser light from said fiber exit, wherein said exit optics yields a focused beam generating a spark sufficient for igniting a fuel and air mixture.

2. The system as claimed in claim 1, wherein at least one of said exit optics are selected from the group consisting of a lens, a plurality of lenses, a curved mirror, a plurality of curved mirrors, diffractive optics, active optics, adaptive optics, and a combination thereof.

3. The system as claimed in claim 1 wherein said exit beam of laser light has an exit angle of less than about 0.03 radians when exiting said fiber exit.

4. The system as claimed in claim 1, wherein said fiber laser includes an enlarged end cap at the fiber exit.

5. The system as claimed in claim 1, wherein said fiber exit comprises a convex shape.

6. The system as claimed in claim 1, further comprising a multiplexed diode pump connected to said fiber laser and at least one other fiber laser.

7. The system as claimed in claim 6, further comprising a plurality of fiber lasers.

8. The system as claimed in claim 1, further comprising a window operatively associated with at least one of said spark plug or said spark plug well.

9. A system for generating a spark, comprising:

a fiber laser for generating a laser beam, wherein said laser beam exits said fiber laser at a fiber exit as an exit beam of laser light; and

a means for focusing said exit beam of laser light generating a spark sufficient for igniting a fuel and air mixture.

10. The system as claimed in claim 9, wherein said exit beam of laser light has an exit angle of less than about 0.03 radians when exiting said fiber exit.

11. The system as claimed in claim 9, wherein said fiber laser includes an enlarged end cap at the fiber exit.

12. The system as claimed in claim 9, wherein said means for focusing includes an integral focusing lens at said fiber exit.

13. The system as claimed in claim 12, wherein said integral focusing lens comprises a convex shape.

14. The system as claimed in claim 9, further comprising means for multiplexing to said fiber laser and to at least a second fiber laser.

15. The system as claimed in claim 9, wherein a least a portion of said means for focusing resides in a spark plug.

16. The system as claimed in claim 15, wherein said spark plug may be inserted into a combustion engine.

17. The system as claimed in claim 16, wherein said means for focusing comprises a window proximate the fuel and air mixture in the combustion engine.

18. A method of generating a spark, comprising:

providing a fiber laser for generating a laser beam through a fiber exit of the fiber laser;

generating the spark using exit optics in optical communication with the fiber exit, wherein the exit optics receives the laser beam from the fiber exit, and wherein the exit optics yields a focused beam for generating the spark.

19. The method as claimed in claim 18, wherein said exit optics is operatively associated with a spark plug interconnected to a combustion engine.

20. The method as claimed in claim 18, further comprising directing the laser beam to a plurality of spark targets using a multiplexer.