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Publication numberUS2985797 A
Publication typeGrant
Publication dateMay 23, 1961
Filing dateOct 30, 1958
Priority dateOct 30, 1958
Publication numberUS 2985797 A, US 2985797A, US-A-2985797, US2985797 A, US2985797A
InventorsRoberts John G, Williams James L
Original AssigneeWestinghouse Electric Corp
Export CitationBiBTeX, EndNote, RefMan
External Links: USPTO, USPTO Assignment, Espacenet
Application of semiconductors to ignition circuitry
US 2985797 A
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Description  (OCR text may contain errors)

y 1961 J. L. WILLIAMS ETAL 2,985,797

APPLICATION OF SEMICONDUCTORS TO IGNITION CIRCUITRY Filed 001;. 50-, 1958 INVENTOR3 James L. Williams 8 John G. Roberts BY FCI p ATTORNEY WITNESSES A Kai/4% United States Patent APPLICATION OF SEMICONDUCTORS TO IGNITION CIRC'UITRY James L. Williams, Prairie Village, Kans., and John G. Roberts, Cincinnati, Ohio, assignors to Westinghouse Electric Corporation, East Pittsburgh, Pa., a corporation' of Pennsylvania Filed Oct. 30, 1958, Ser. No. 780,914 3 Claims. (Cl. 315-209) This invention relates to aircraft engine ignition systems and more particularly to an improvement in the existing low voltage, high energy capacitor discharge ignition systems.

One broad object of this invention is to eliminate all moving parts from the existing ignition systems and thus effect a greater reliability.

Another object of this invent-ion is the provision of arc ignition system that is smaller in size and thus less in weight and cost than the existing prior art ignition systems.

Other objects of this invention comprise an ignition system having lower power requirements, less radio interference, higher efilciency, and faster operation than the existing prior art ignition system.

Other objects and advantages will become more apparent from a study of the following specification and the accompanying drawing.

The accompanying drawing shows the invention in diagrammatic form as applied to a portion of the circuitry now in vogue with aircraft jet engine ignition systems.

A better understanding of the contribution to the prior art can very likely be had from a study of a portion of the existing prior art circuitry.

Let the assumption be that the transformer T has its primary winding TP supplied with an alternating current input. The transformer steps the voltage up to some higher value. This higher output voltage from the secondary TS is rectified by the rectifiers RBI, RE2, RE3, etc. The purpose of the rectifiers in series is to provide a rectification of a relatively high voltage. The number of rectifier tubes in series will depend on the output voltage, and the number needed will be directly proportional to the output voltage.

The rectified voltage from the rectifier tubes charges the capacitor C2 and the charge will rise until the breakdown voltage of the spark gap tube SGT is reached. This spark gap tube is a gaseous tube which will conduct large transient current at the instant the spark gap tube breaks down. This breakdown of the spark gap tube usually occurs at from 1 to kilovolts.

Upon conduction of the spark gap tube, the high volt age stored in the charged capacitor C2 is discharged through the spark igniter, or igniter plug IP. The igniter plug IP is a shunted surface gap type spark plug, having the high resistance shunt R2, which will fire at a very low voltage. This firing voltage is between 800 and 1800 volts and is very low with reference to voltage at the capacitor terminals of capacitor C2 when this capacitor begins to discharge.

In view of the low firing voltage of the spark plug this ignition system is usually called a low voltage, high en ergy capacitor discharge ignition system. This system has an advantage over other systems due to the large availability of electrical energy at a comparatively low voltage. In this case,

Electric energy= CE.

where C=the capacitance of the capacitor C2 and E: the charging voltage of the capacitor C2.

Another advantage of this system lies in the use of the shunted surface igniter plug IP. This advantage is due 0 the physical properties of the shunted surface plug which allows it to fire at a rather low voltage (800 to' 1800 volts) and to the physical construction which does not allow the plug to foul even when the firing end is covered with raw fuel or even carbon.

In the existing prior art circuitry the alternating current input to the transformer T is obtained from an involved alternating current supply or from a direct current supply by the use of elaborate, heavy and expensive switching means.

The broad novel features of this ignition system is the substitution of a simple oscillator circuit which allows the use of a direct current power input without having to use a mechanical vibrator, or other rapidly operating switching means, to provide the electrical pulses which are necessary to provide proper transformer action.

In this mentioned simple oscillator, B represents the direct current supply and S a switch for connecting the resistor R1 and inductance coil' L and capacitor C1 to the source of direct current. A hyperconductive negative resistance diode, known as a Dynister, is connectedin series with the primary winding TP and these elements are connected across the terminals of the capacitor C1.

The operation of this oscillator circuit is as follows. The instant switch S is closed, the capacitor C1 begins to charge, the charging rate is rather high, and is merely limited by the resistor R1 and inductance coil L.

At, or near, full charge of the capacitor C1 the voltage at the terminals of the Dynister Dy becomes sufficiently high for the diode to break down and become conducting and thus a surge of current flows through the primary winding TP. The resistor R1 and inductance L allows the capacitor C1 to discharge and repeat the cycle again and again as long as switch S remains closed. The necessary pulsating current is thus supplied to the transformer, thus providing the proper transformer action necessary to operate the ignition unit. Proper selection of the resistor R1, inductance coil L, and capacitor C1, can provide a very rapid charging rate for the capacitor C1, and an operation of the transformer primary TP at a higher voltage than the voltage of the direct current input B.

From the foregoing it will be apparent that all mechanical oscillators and switching means are eliminated. Further mechanical oscillators are limited to frequencies equal to and less than cps. The circuit herein disclosed may be tuned to one kc. and thus give a much higher spark rate than prior art devices.

The circuit herein disclosed can be used to great advantage in the jet engine and possibly in the rocket engine ignition field. In these and other fields the great advantage of the circuitry herein disclosed over existing prior art ignition systems lies in the large reduction in size and weight and the removal of all mechanical moving parts.

While but one embodiment has been disclosed the invention is not limited to the one showing but includes such modifications as fall within the spirit and scope of this invention.

We claim as our invention:

1. In a low voltage, high energy capacitor discharge ignition system, including a shunted surface gap type spark plug, a spark gap tube connected in series with the plug, a charging capacitor connected across the tube and plug, current rectifying means, a transformer having a low voltage primary winding and a high voltage output secondary winding, said secondary winding being connected in a loop circuit with the rectifying means and the capacitor, in combination with, a source of direct current, switching means, an electric oscillator circuit tuned to a relatively high frequency connected through said switching means to the primary winding and to the source of direct current, said oscillator circuit including a capacitor and impedance means connected in a loop circuit with the source of direct current by said switching means, and a hyperconductive negative resistance diode connected in series with the primary winding and selected to break down and conduct to discharge the capacitor each time the charge on the capacitor is increased to a selected magnitude.

2. In a low voltage, high energy capacitor discharge ignition system, including a shunted surface gap type spark plug, a spark gap tube connected in series with the plug, a charging capacitor connected across the tube and plug, current rectifying means, a transformer having a low voltage primary winding and a high voltage output secondary winding, said secondary winding being connected in a loop circuit with the rectifying means and the capacitor, in combination with, a source of direct current, switching means, an electric oscillator circuit including a hyperconductive negative resistance diode, connected in series with the primary winding, a capacitor connected across the primary winding and the diode connected in series with the primary winding, and impedance means connected through said switching means in a loop circuit with the last named capacitor and the source of direct current.

3. In a low voltage, high energy capacitor discharge ignition system, including a shunted surface gap type spark plug, a spark gap tube connected in series with the plug, a charging capacitor connected across the tube and plug, current rectifying means, a transformer having a low voltage primary winding and a high voltage output secondary winding, said secondary winding being connected in a loop circuit with the rectifying means and the capacitor, in combination with, a source of direct current, switching means, an electric oscillator circuit including a resistor, a capacitor, and an inductance connected through said switching means in a loop circuit with the source of direct current, a hyperconductive negative resistance diode connected in series with the primary winding, and the last named capacitor being connected across the series circuit formed by the primary winding and said hyperconductive negative resistance diode.

References Cited in the file of this patent UNITED STATES PATENTS 2,328,444 Francis Aug. 31, 1943 2,347,286 Sandretto Apr, 25, 1944 2,544,477 West Mar. 6, 1951 2,571,789 Tognola Oct. 16, 1951 2,837,698 Segall June 3, 1958

Patent Citations
Cited PatentFiling datePublication dateApplicantTitle
US2328444 *Nov 17, 1941Aug 31, 1943Francis Oliver TIgnition system
US2347286 *Jun 19, 1942Apr 25, 1944United Air Lines IncIgnition system
US2544477 *Dec 28, 1949Mar 6, 1951Rolls RoyceSpark type ignition system for combustion engines
US2571789 *Jun 9, 1949Oct 16, 1951Bendix Aviat CorpElectrical apparatus
US2837698 *Sep 29, 1953Jun 3, 1958Bendix Aviat CorpElectrical apparatus
Referenced by
Citing PatentFiling datePublication dateApplicantTitle
US3219880 *Jun 27, 1963Nov 23, 1965SpectrolabAutomatic starter for the ignition of gas arc lamps
US3247887 *Sep 4, 1962Apr 26, 1966Penn ControlsSpark ignition system
US3253187 *Apr 5, 1962May 24, 1966Gen Motors CorpBreakerless transistor ignition system
US3269447 *Jan 16, 1964Aug 30, 1966Controls Co Of AmericaFuel control and ignition system
US3336506 *Feb 24, 1964Aug 15, 1967Edgar FrankElectric ignition device for oils and gases
US3338288 *Feb 28, 1964Aug 29, 1967Whirlpool CoElectronic spark ignitor
US3361932 *Apr 27, 1964Jan 2, 1968Rotax LtdA.c. operated spark ignition apparatus with compensation for changes in the frequency of the a.c. source
US3416512 *Jan 9, 1967Dec 17, 1968Alvin MintzInfrared heating system
US3425780 *Sep 26, 1966Feb 4, 1969Liberty Combustion CorpFluid fuel igniter control system
US3681001 *May 15, 1970Aug 1, 1972Liberty Combustion CorpFluid fuel igniter control system
US3943905 *Mar 25, 1974Mar 16, 1976Gunter HartigMethod and device for igniting combustible substances
US3982518 *Jan 28, 1975Sep 28, 1976Fournitures Internationales De Materieles ElectroniquesElectronic ignition device for internal combustion engines
US4411247 *Apr 8, 1981Oct 25, 1983Sanke Electric Co., Ltd.Distributorless ignition system for multicylinder internal-combustion engines
US4487192 *Apr 18, 1983Dec 11, 1984Ford Motor CoFor an internal combustion engine
US5245252 *May 8, 1991Sep 14, 1993Frus John RApparatus and method for providing ignition to a turbine engine
US5399942 *Jun 8, 1993Mar 21, 1995Unison Industries Limited PartnershipApparatus and method for providing ignition to a turbine engine
US5561350 *Feb 24, 1995Oct 1, 1996Unison IndustriesIgnition System for a turbine engine
US5754011 *Jul 14, 1995May 19, 1998Unison Industries Limited PartnershipMethod and apparatus for controllably generating sparks in an ignition system or the like
US6034483 *Sep 2, 1997Mar 7, 2000Unison Industries, Inc.Method for generating and controlling spark plume characteristics
US6353293Mar 6, 2000Mar 5, 2002Unison IndustriesMethod and apparatus for controllably generating sparks in an ignition system or the like
US7095181Mar 1, 2002Aug 22, 2006Unsion IndustriesMethod and apparatus for controllably generating sparks in an ignition system or the like
Classifications
U.S. Classification315/209.00T, 123/650, 315/209.00R, 439/92, 123/655, 123/627, 123/654, 315/209.0CD
International ClassificationF02P3/00, F02P3/01
Cooperative ClassificationF02P3/01
European ClassificationF02P3/01