High pulse rate spark ignition system

• US 6,457,464 B1
• Filed: 09/25/2000
• Issued: 10/01/2002
• Est. Priority Date: 04/29/1996
• 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): Mancene, Gene
• Assistant Examiner(s): Castro, Arnold
• Application Number:
  US09/669,421
• Time in Patent Office: 736 Days
• Field of Search: 123/598, 123/604, 123/605, 335/281, 335/296, 335/297, 335/213, 164/423, 336/212, 336/213, 336/229, 296/05
• US Class Current: 123/605
• 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: H01F 38/12 Ignition, e.g. for IC engines

Abstract

A spark ignition system for igniting fuel in an internal combustion engine is described. The spark ignition system includes a magnetic core-coil assembly having a ferromagnetic amorphous metal magnetic core and driver electronics. 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.

Claims

1. A spark ignition system for igniting fuel in an internal combustion engine having at least one combustion chamber, comprising:

a. a magnetic core-coil assembly including a magnetic core comprising at least one tape wound toroid including a ferromagnetic amorphous metal alloy having a composition defined essentially by the formula;

M_70-85 Y_5-20 Z_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 (1) 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;

a low-voltage primary winding; and

a secondary winding for a high voltage output; and

b. 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 pray 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 spark 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. The spark ignition system of claim 1 wherein the magnetic core comprises a single tape-wound toroid encircled by the primary winding and the secondary winding.

4. The spark ignition system of 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. The spark ignition system of claim 4 wherein said magnetic core comprises segmented cores.

6. The spark ignition system of 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. The spark ignition system of claim 1 wherein the ferromagnetic amorphous metal alloy is an iron-base alloy.

8. The spark ignition system of 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. The spark ignition system of 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. The spark ignition system of claim 9 wherein the ferromagnetic amorphous metal has a composition defined essentially by the formula Fe₈₀B₁₁Si₉.

11. The spark ignition system of 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. The spark ignition system of claim 1 wherein the ferromagnetic amorphous metal alloy is heat treated.

13. The spark ignition system of claim 1 wherein each of the tape-wound toroids is gapped.

14. The spark ignition system of claim 1 wherein each of the tape-wound toroids is non-gapped.

15. The spark ignition system of claim 1 wherein the ferromagnetic amorphous metal alloy has a permeability ranging from about 250 to 500.

16. The spark ignition system of 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. The spark ignition system of 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. The spark ignition system of 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. The ignition system of claim 1 wherein the core-coil assembly is adhesively secured inside a housing by a potting compound.

20. The spark ignition system of 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. The spark ignition system of 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. The spark ignition system of 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. The spark ignition system of 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. The spark ignition system of 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. The spark ignition system of 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 magnetic 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_70-85 Y_5-20 Z_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 electrically connecting driver electronics to the primary winding of 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-oil 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.

29. A magnetic core-coil assembly comprising a magnetic core comprising at least one tape wound toroid, a primary winding for low voltage excitation, and a secondary winding for high voltage output, the toroid consisting essentially of a ferromagnetic amorphous metal alloy having a permeability ranging from about 250 to 500 and a composition defined essentially by the formula:

M_70-85 Y_5-20 Z_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.

30. The magnetic core-coil assembly of claim 29 wherein said ferromagnetic amorphous metal alloy contains at least 70 atom percent Fe, at least 5 atom percent B, and at least 5 atom percent Si, with the proviso that the total content of B and Si is at least 15 atom percent.

31. The magnetic core-coil assembly of claim 29 wherein the ferromagnetic amorphous metal alloy has a composition defined essentially by the formula Fe₈₀B₁₁Si₉.

32. The magnetic core-coil assembly of claim 29 wherein the magnetic core comprises a single tape-wound toroid encircled by the primary winding and the secondary winding.

33. The magnetic core-coil assembly of claim 29, the core-coil assembly being adhesively secured inside a housing by a potting compound.

34. The magnetic core-coil assembly of claim 33 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.

35. The magnetic core-coil assembly of claim 33 wherein the potting compound comprises an anhydrous, two-component epoxy having strong adhesion to said core-coil assembly, high temperature electrical performance and good thermal shock resistance.

36. The magnetic core-coil assembly of claim 33 wherein the potting compound comprises a silicone rubber based potting compound.

37. The magnetic core-coil assembly of claim 33 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.

38. The magnetic core-coil assembly of claim 33 wherein the housing comprises an injection moldable glass-filled thermoplastic polyester with a T_g near the maximum operating temperature of said assembly and a coefficient of thermal expansion matched to that of said potting compound.

39. The magnetic core-coil assembly of claim 33 wherein the housing comprises a member of the group consisting of polyphenylene ether/polypropylene blends, polymethylpentene/polyolefin blends and polycylcolefin/polyolefin blends.

40. The magnetic core-coil assembly of claim 29 wherein the 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.

41. The magnetic core-coil assembly of claim 29 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 100 microseconds, provides a discharge time less than about 200 microseconds, and provides spark energy greater than about 10 millijoules per pulse when operated with said driver electronics.

42. The magnetic core-coil assembly of claim 29 wherein the core has a core loss of less than about 100 W/kg when measured at room temperature and excited at a frequency of 100 kHz to a peak sinusoidal flux density of 0.1 T.

43. The magnetic core-coil assembly of claim 42 wherein the core loss is less than about 65 W/kg.

44. The magnetic core-coil assembly of claim 29 wherein said core has a permeability ranging from about 100 to 500.