High pulse rate ignition system

• US 6,608,543 B2
• Filed: 10/28/2002
• Issued: 08/19/2003
• Est. Priority Date: 09/18/1997
• Status: Expired due to Term

• Current Assignee: Metglas, Inc. (Proterial Ltd.)
• Original Assignee: Honeywell International Inc.
• Inventors: Fish, Gordon E., Rapoport, William R., Grimes, Donald Allen, Papanestor, Paul A., VanBuskirk, Bruce
• Primary Examiner(s): MAI, ANH T
• Application Number:
  US10/281,865
• Publication Number:
  US 20030048165A1
• Time in Patent Office: 295 Days
• Field of Search: 123/634, 123/635, 123/599, 123/406, 336/90, 336/92, 336/96, 336/107, 336/198, 296/021, 296/06, 296/05
• US Class Current: 336/90
• CPC Class Codes: F02P 3/02 having inductive energy storage, e.g. arrangements of induction coils ignition coils structurally combined with sparking plugs F02P13/00; constructional details of ignition coils H01F38/12
• CPC Class Codes: F05B 2220/50 for auxiliary power units (APU's)
• CPC Class Codes: H01F 38/12 Ignition, e.g. for IC engines
• CPC Class Codes: Y10T 29/4902 Electromagnet, transformer or inductor

Abstract

An ignition system for igniting fuel in a gas turbine or diesel engine is described. The system includes a magnetic core-coil assembly having a magnetic core comprising at least one tape wound toroid of ferromagnetic amorphous metal alloy, a primary winding and a secondary winding. Also included are driver electronics for applying voltage to a spark plug to cause a spark to ignite the fuel. The core-coil assembly and driver electronics are capable of operating with a rapid charge and discharge cycle to produce a high spark pulse rate. In another aspect, a magnetic core-coil assembly is disclosed which has a magnetic core comprising at least one tape wound toroid of ferromagnetic amorphous metal alloy having a permeability ranging from about 250 to 500, a primary winding for low voltage excitation and a secondary winding for high voltage output.

Claims

1. An ignition system for igniting fuel in a gas turbine or diesel engine comprising:

a magnetic core coil assembly including a magnetic core comprising at least one tape wound toroid including a ferromagnetic amorphous metal alloy, a primary winding for low voltage excitation, and a secondary winding for high voltage output, the ferromagnetic amorphous metal alloy having a composition defined essentially by the formula;

M_70-85Y_5-20Z_0-20, subscripts in atom percent, where “

M”

is at least one of Fe, Ni and Co, “

Y”

is at least one of B, C and P, and “

Z”

is at least one of Si, Al and Ge;

with the provisos that (i) up to 10 atom percent of component “

M”

can be replaced with at least one of the metallic species Ti, V, Cr, Mn, Cu, Zr, Nb, Mo, Ta, Hf, Ag, Au, Pd, Pt, and W, (ii) up to 10 atom percent of components (Y+Z) can be replaced by at least one of the non-metallic species In, Sn, Sb and Pb; and

(iii) up to about one (1) atom percent of the components (M+Y+Z) can be incidental impurities; and

driver electronics for applying a voltage to an electrode of a spark plug, wherein the driver electronics are associated with the core-coil assembly and are capable of supplying a current to the primary winding, the current resulting in a magnetomotive force that produces a magnetic field in the core in which energy is stored, wherein the driver electronics includes means for interrupting the current flow through the primary winding of the core-coil assembly causing the magnetic field within the core to collapse and thereby induce across the secondary winding a voltage that is carried to the electrode of the spark plug causing production of a spark igniting the fuel, and wherein the core-coil assembly and driver electronics are capable of operating with a rapid charge and discharge cycle to produce a high spark pulse rate.

2. The ignition system of claim 1 wherein the driver electronics comprises a DC voltage source, a capacitor, a switching element capable of opening and closing, and a timing control circuit.

3. An ignition system as recited by claim 1 wherein the magnetic core comprises a single tape-wound toroid encircled by the primary winding and the secondary winding.

4. An ignition system as recited by claim 1 wherein the magnetic core comprises a plurality of the tape-wound toroids secured in substantially coaxial alignment, the primary winding encircling all of said toroids, and the secondary winding comprises a plurality of secondary sub-windings connected in series, one of said secondary sub-windings encircling each of the toroids.

5. An ignition system as recited in claim 4, wherein said magnetic core comprises segmented cores.

6. An ignition system as recited in claim 4, wherein the assembly includes an internal voltage distribution that is segmentally stepped from bottom to top, the number of segments being determined by the number of tape wound toroids in the core.

7. An ignition system as recited by claim 1, wherein the ferromagnetic amorphous metal alloy is an iron-base alloy.

8. An ignition system as recited by claim 7, wherein the ferromagnetic amorphous metal alloy has been heat-treated at a temperature near the alloy'"'"'s crystallization temperature and partially crystallized.

9. An ignition system as recited by claim 7, wherein the ferromagnetic amorphous metal alloy contains at least 70 atom percent Fe, at least 5 atom percent B, and at least 5 atom percent Si, and wherein the total content of B and Si is at least 15 atom percent.

10. An ignition system as recited by claim 9, wherein the ferromagnetic amorphous metal has a composition defined essentially by the formula Fe₈₀B₁₁Si₉.

11. An ignition system as recited by claim 7, wherein the ferromagnetic amorphous metal alloy has been heat-treated below the alloy'"'"'s crystallization temperature and, upon completion of the heat treatment, remains substantially in an amorphous state.

12. An ignition system as recited by claim 1, wherein the ferromagnetic amorphous metal alloy is heat treated.

13. An ignition system as recited by claim 1 wherein each of the tape-wound toroids is gapped.

14. An ignition system as recited by claim 1 wherein each of the tape-wound toroids is non-gapped.

15. An ignition system as recited by claim 1 wherein the ferromagnetic amorphous metal alloy has a permeability ranging from about 250 to 500.

16. An ignition system as recited in claim 1 wherein the core-coil assembly generates a voltage rise ranging from about 200 to 500 nanoseconds, has an output impedance ranging from about 30 to 100 ohms, produces an open circuit voltage greater than about 25 kV, delivers peak current greater than about 0.5 amperes through the spark, provides a charge time of less than about 150 microseconds, provides a discharge time less than about 200 microseconds, and provides spark energy greater than about 5 millijoules per pulse when operated with the driver electronics.

17. An ignition system as recited in claim 1 wherein the driver electronics is powered by a voltage source of at least about 5 volts, and is capable of delivering pulse rates of at least about 500 Hz.

18. An ignition system as recited in claim 1 wherein the voltage across the secondary winding reaches more than 10 kV with a magnetomotive force of less than 70 ampere-turns and more than 20 kV with a magnetomotive force of 75 to 200 ampere-turns within about 20 to 150 microseconds.

19. An ignition system as recited in claim 1, wherein the core-coil assembly is adhesively secured inside a housing by a potting compound.

20. An ignition system as recited in claim 19, wherein the potting compound comprises a two part elastomeric polyurethane system having strong adhesion to said core-coil assembly, high dielectric strength, hardness in the mid Shore A range and a low dielectric constant.

21. An ignition system as recited in claim 19, wherein the potting compound comprises an anhydrous, two-component epoxy having strong adhesion to the core-coil assembly, high temperature electrical performance and good thermal shock resistance.

22. An ignition system as recited in claim 19, wherein the housing comprises a flexible high use temperature plastic with a high dielectric strength, low dielectric constant, good electrical properties, and good chemical resistance.

23. An ignition system as recited in claim 19, wherein the housing comprises an injection moldable glass-filled thermoplastic polyester with a T_g near the maximum operating temperature of the assembly and a coefficient of thermal expansion matched to that of the potting compound.

24. An ignition system as recited in claim 19, wherein the housing comprises a member of the group consisting of polyphenylene ether/polypropylene blends, polymethylpentene/polyolefin blends and polycylcolefin/polyolefin blends.

25. An ignition system as recited in claim 19, wherein the housing comprises a polyphenylene ether/polypropylene blend that is flexible, has a low dielectric constant, good electrical properties, good chemical resistance and is injection moldable and the potting compound comprises a two part elastomeric polyurethane.

26. A method for producing a core-coil assembly comprising:

producing a magnetic assembly that includes a magnetic core comprising at least one tape wound toroid including a ferromagnetic amorphous metal alloy, a primary winding for low voltage excitation, and a secondary winding for high voltage output, the ferromagnetic amorphous metal alloy having a composition defined essentially by the formula;

M_70-85Y_5-20Z_0-20, subscripts in atom percent, where “

M”

is at least one of Fe, Ni and Co, “

Y”

is at least one of B, C and P, and “

Z”

is at least one of Si, Al and Ge;

with the provisos that (i) up to 10 atom percent of component “

M”

can be replaced with at least one of the metallic species Ti, V, Cr, Mn, Cu, Zr, Nb, Mo, Ta, Hf, Ag, Au, Pd, Pt, and W, (ii) up to 10 atom percent of components (Y+Z) can be replaced by at least one of the non-metallic species In, Sn, Sb and Pb; and

(iii) up to about one (1) atom percent of the components (M+Y+Z) can be incidental impurities; and

adhesively securing the core-coil assembly with a potting compound to a housing.

27. The method of claim 26 further comprising connecting driver electronics to the core coil assembly for applying a voltage to an electrode of a spark plug, wherein the driver electronics supplies a current to the primary winding, the current resulting in a magnetomotive force that produces a magnetic field in the core in which energy is stored, wherein the driver electronics includes means for interrupting the current flow through the primary winding of the core-coil assembly causing the magnetic field within the core to collapse and thereby induce across the secondary winding a voltage that is carried to the electrode of the spark plug causing production of a spark igniting the fuel, and wherein the core-coil assembly and driver electronics are capable of operating with a rapid charge and discharge cycle to produce a high spark pulse rate.

28. The method of claim 26 further comprising preparing and plasma cleaning the surfaces of each of the components of the core-coil assembly and the housing prior to adhesively securing the core-coil assembly to the housing with potting compound.