US2413948A

US2413948A - Ignition system

Info

Publication number: US2413948A
Authority: US
Publication date: 1947-01-07
Anticipated expiration: 1964-01-07

Description

Jan. 7, 1947. BRINSQN 2,413,948

IGNITION SYS TEM Filed June 4. 1943 INVENTOR. lye/v7 4 BY A T'I'ORNEY A PatenteciJan- 7, f

IGNITION SYSTEM Hui- A. Brinson, Sidney, N. Y., assi gnor to Bendix Aviation Corporation, corporation of Delaware New York, N. Y 8.

Application June 4, 1943, Serial No. 489,687

This invention relates to electrical apparatus and more particularly to'an ignition system for internal combustion engines and the like.

One of the objects of the present invention is to provide novel means for creating sparks at the gaps of spark plugs in the cylinders of anengine. Another'obiect of the invention is to provide 11 Claims. (or. 123-148) novel means of the above character which are operable independently of the speed of the engine.

Still another object is to provide a novel method of creating sparks across a gap, such as across the points of a spark plug in the cylinder of an internal combustion engine.

A further object is to provide a'novel booster ignition system adapted for use in starting internal combustion engines which are normally operated 'by a magneto-generator or similar means.

The above and further objects and novel features of the invention will more fully appear from the following detailed description when the same is read in connection with the accompanying.

drawing. It is to be expressly understood, however, that the drawing is for the purpose of illustration only and is not intended as a deflnition of the limits of the invention, reference for this latter purpose being primarily had to the appended claims.

In the drawing, the figure is a diagrammatic view illustrating one form of ignition system embodying the present invention.

A single embodiment of the invention is illustrated, by way of example, in the form of an ignition system for a 9-cylinder engine wherein the electrical energy for normal operation of the engine is supplied 'by a magneto-generator or the like. Any of many well-known types of magnetos may be employed for carrying out the invention, the one shown in the drawing consisting of a 4-pole magnetic rotor- 5 adapted to be driven in any suitable manner by the engine and a 2-pole stator 6 adapted to cooperate in a manner well understood in the art'with rotor 5. Wound on stator 6 is an ignition coil consisting of a primary or low tension winding I and a secondary or high tension winding 8.

One end of primary winding 1 is preferably grounded, as at 9, and has a circuit breaker-consisting of a movable point or contact l0 anda stationary point or contact ll connected across it in the usual well-known manner to form a primary or low voltage circuit. The points of the circuit breaker l8, II are normally biased to engaged or closed position, either by the resiliency of the movable arm I! or by other suitable resilient means (not shown). A rotatable cam i3,

which may be of the compensated type for radial engines, or any other suitable known means may be provided for periodically separating the points of circuit breaker Hi, i i to thereby interrupt the circuit through primary winding 7. In

order to eliminate or minimize arcing at points 18, it when the same are separated, a condenser ll may be connected across said points.

One end of secondary winding 8 is preferably connected to the grounded or low potential end of primary winding 1 and the other end of said secondary winding is connected by a lead l5 to the input terminal l6 of a high tension ignition distributor l1. Current from lead I5 is picked up by the rotating arm l8 of the distributor and delivered in a well-known manner to thecircularly arranged output terminals l9 which are in turn connected by leads to spark-plugs 2| in the cylinders of an engine. One terminal of each spark plug is grouded, as at 22.

In the operation of the ignition system thus tar described, rotation of rotor 5 induces alternating' current at relatively low voltage in the primary circuit, including winding 1 and circuit breaker I0, I i. At or about each time the induced current in the primary circuit reaches its maximum value, said circuit is interrupted by the opening of circuit breaker H), .II and the resulting sudden drop of the current and, hence, sudden collapse of the magnetic field about windings I and 8 induces a current at high voltage in secondary winding 8. Rotor 5, cam l3 and distributor arm I8 are preferably all driven by the engine in timed relation so that the high voltage current thus induced in the secondary circuit 'will flow from winding 8 through lead l5 and predetermined sequence, as is well understood in the art.

When starting an engine on which the above system is installed, the starting motor does not ordinarily rotate the engine crankshaft and,

hence, rotor 5 suiliciently fast to generate enough energy to fire'th'e spark plugs in the engine cylinders. Accordingly, for starting purposes, a

, source of electrical energy, such as a battery 23,

may be employed. The present invention contemplates novel means for utilizing the energy from battery 23 in a novel manner .n conjunction with the ignition system heretofore described. In the form shown, one terminal of the 3 battery is connected to ground t 24 d th other terminal is connected through a switch 25 to a coil of relatively high self-induction wound on a metallic core 21. The other end of coil 28 is connected by means of a lead 28 to the ungrounded or high potential end of primary winding 1. Switch 25 may be a manually operated switch normally biased to open position, as shown, or it may be a switch adapted to be automatically opened whenever the engine is operating sufficiently fast to utilize the energy from magneto 5, 6.

For the purpose of rendering the ignition system inoperative and, hence, prevent operation of the engine on which the same is mounted, a suitable ignition switch 29 may be provided for grounding the high potential end of primary winding 1', as at 30. Thus, when switch 29 is in closed position, both ends of primary winding I will be connected to ground and thereby render circuit breaker l0, H incapable of interrupting the primary circuit.

The starting or booster circuit is rendered operative by closing switch 25 when ignition switch 29 is in open position, it being understood that the closing of switch 25 may be effected by closing the circuit to a starting motor which is operative to slowly turn the crankshaft of the engine on which the ignition system is installed.

Current then flows from battery 23 through coil 26 and lead 28, Since circuit breaker l0, Ii and primary winding 1 are connected in parallel with ,respect to battery 23, the current flowing through lead 28 divides when the circuit breaker points are in closed position, a portion of said current flowing through each of the parallel connected branches of the circuit. The major portion of the current takes the path of least resistance and, hence, flows to ground at 9 through circuit breaker H], II. Thus, when the points of the latter are separated by cam l3, thereby making it necessary for the entire battery current to pass through a circuit of higher resistance, 1. e., through primary winding I, there will be a sudden decrease in the value of-the current flowing and, hence, a sudden change in the magnetic field around booster coil 26. This change in the magnetic field induces current in the booster coil, which current rises rapidly, though momentarily, to a relatively high value. This sudden increase or surge of current flows through primary winding 1 and causes a rapid increase in the magnetic fluxaround said winding. This sudden'increase of magnetic flux is effective to induce a high potential current in secondary winding 8, which current is delivered to the spark plugs through distributor II in the manner heretofore described and is capable of causing the necessary arcing across the gaps of said spark plugs. When the engine begins to run sufllciently fast. switch 25 may be released or automatically opened and the required energy for firing the spark plugs will be supplied by magneto 5, 6.

In one suitable embodiment of the invention,

a standard Scintilla magneto with standard coil windings i and 8 was employed as a main source of electrical energy and a battery having a rated voltage of 24 volts was used as the booster source. condenser having a capacitance of approximately .25 to .35 microfarad may be used at M. The inductance of coil 28 may vary, a coil having an inductance of from 20 to 30 millihenries being preferable. When a battery of the above voltage rating is used, it is preferable that the resistance In such a system, a standard magnetoof lead 28 does not exceed one ohm. The foregoing values are merely exemplary and may vary widely in different installations.

There is thus provided an ignition system starting an internal combustion engine which is normally supplied with electrical energy by a magneto. A novel booster system is provided for engine starting purposes, which system utilizes the circuit breaker of the main ignition system with which it is used for timing purposes and utilizes the surges of self-induced current in a booster coil for creating the desired arcing at the spark plugs, Additionally, the novel system contemplated by the invention requires a minimum of wiring and, hence, reduces the weight. cost, upkeep, required space, and the possibilities of failures to a minimum.

Although only a, single embodiment of the invention is illustrated in diagrammatic form, it is tobe expressly understood that'various changes may be made therein without departing from the spirit and scope of the invention, as the same will now be understood by those skilled inthe art. For-example, the booster coil and i8- nition switch may be connected into the main ignition circuit at points other than those illustrated. The various units, such as the magneto and distributor, may assume different formsthan those illustrated, the number of cylinders or spark plugs may'be varied, and'the values of the resistances, inductances, etc., given as exemplary, may be varied in ignition systems for different engines. For a definition of the limits of the invention, reference is had primarily to the appended claims.

What is claimed is:

1. In ignition apparatus, a source of uni-directional electrical current, an inductance electrically connected at one end to a terminal of said source, circuit breaker means having one side thereof connected to the -other end of said inductance, the other side of said circuit breaker means and the other terminal of said source being connected to a common ground, an induction coil having the primary winding thereof connected in parallel with said circuit breaker means, the resistance in the parallel-connected branches of the above circuit being so distributed that a major portion of the current from said source flows through said circuit breaker means when the latter is in closed position, a condenser connected in parallel with said circuit breaker means, means for periodically actuating said circuit breaker means to open position, and a spark gap in series with the secondary winding of said induction coil.

2. In ignition apparatus, a source of uni-directional electrical current, an inductance elecoo trically connected at one end to a terminal of said source, circuit breaker means having one side thereof connected to the other end of said inductance, the other side of said circuit breaker means and the other terminal of said source being '65 connected to a common ground, an induction coil having the primary winding thereof connected in parallel with said circuit breaker means, the resistance in the parallel-connected branches of the above circuit being so distributed that a 7 major portion of the current from said source flows through said circuit breaker means when the latter is in closed position, a condenser connected in parallel with said circuit breaker means, means for periodically actuating said circuit breaker means to open position, a spark gap wherein novel simplified means are provided for ground, a coil hail of said source to in series with the secondary winding of said induction coil, and switch means for disconnecting said inductance from said source.

3. In ignition apparatus, a source of uni-directional electrical current, a coil of relatively high self-induction, circuit breaker means connected in series with said coil across said source, a transformer having the primary winding, thereof connected in parallel with said circuit breaker means, the resistance to the flow of electrical current through said winding being such that a major portion of thecurrent from said source flows through said circuit breaker means when the latter is in closed position, a condenser connected in parallel with said circuit breaker means, means for periodically actuating said circuit breaker means to interrupt the flow of current therethrough, and a spark gap in series with the secondary Winding of said transformer.

4. In ignition apparatus, a source of uni-directional electrical current, acoil of relatively high self-induction, circuit breaker means connected in series with said coil across said source, a transformer having the primary winding thereof connected in parallel with said circuit breaker means, the resistance to the flow of electrical current through said winding being such that a major portion of the current from said source flows through said circuit breaker means when the latter is in closed position, a condenser connected in parallel with said circuit breaker means, means for periodically actuating said circuit breaker means to interrupt the flow of oura circuit breaker, opening said circuit breaker and causing self-induced current from said coil to flow in a surge through the primary winding of a transformer coil, the secondary winding of which is connected in series with said gap, said primary winding being connected in parallel with said circuit breaker.

8. An ignition system for an internal combustion engine comprising a source of unidirectional current, a self-induction coil connected to said source, circuit breaker means connected in circuit with said source and coil for causing the electrical current flowing through said coil from said source to fluctuate and a transformer having the primary winding thereof connected to said coil in parallel with said circuit breaker means for receiving self-induced current from said coil when said circuit breaker means is opened, the sudden increase of current through said primary-winding being adapted to induce the flow of electrical current in the secondary winding of said transformer.

9. Ignition apparatus for an internal combustion engine comprising a source of uni-directional current, an inductance connected to said source to receive the entire power output of said source,

' circuitbreaker means connected in circuit with said inductance and source for causing fluctuarent therethrough, a spark gap in series with the secondary winding of said transformer, and magnetic means for inducing alternating current in said primary winding. 7

5. In an ignition system, a magneto-generator comprising a transformer havingprimary and secondary windings, magnetic means for inducing alternating current in said primary winding, circuit breaker means connected in series with said primary winding, a condenser connected across said circuit breaker means, means connecting one side of said circuit breaker means and one end of said primary winding to a common of relatively high self-induction having one end thereof connected tothe other side of said circuit breaker means, a. source, of

uni-directional electrical current having a terminal thereof connected to the other side of said coil, switch means for disconnecting saidsource and coil, and means connecting the other termisaid common ground.

6. In an ignition system, a magneto-generator wherein electrical current at relatively high voltage is induced in a secondary circuit when circuit breaker means are actuated to interrupt the flow of current induced in a primary circuit by magnetic means a source of uni-directional current, a coil of relatively high self-induction connected to said source in series with said circuit breaker means whereby current induced insaid coil surges through said primary circuit when said circuit breaker means is actuated to open position andinduces a high voltage'current in said secondary circuit.

7. The method of creating sparks across the gap of a spark plug in the cylinder of an in-' ternal combustion 'engine'whic steps of causing uni-directional ectrlcal current to 'flow'through aself-induction coil in series with includes the tions in the electrical current flowing through said coil from said source whereby a, self-induced voltage higher than the voltage of said source is developed across said inductance and a transformer having the primary winding thereof connected in parallel with said circuit breaker means r and in a circuit through which self-induced current surges from said inductance flow for inducing current at still higher voltage in the secondary winding of said transformer.

10. In a magneto ignition system a transforme and means for inducing alternating current in,

the primary winding thereof,-a source of current comprising an induction coil, and means for imposing the current from the said source upon the alternating current in the magneto ignition system comprising a circuit breaker, connected in series with the primary winding and in series with the induction coil, operating in one position to break the alternating current circuit and to send current from the induction coil through the primary winding, and operating in the other position to make the alternating current circuit and to send current from the induction coil to ground whereby the primary winding is supplied with booster current and the induction coil is repeatedly energized.

11'. In a magneto ignition system a transformer and means 'for inducing alternating current in a current and means for combining the energy thereof with the alternating current in the magthe primary winding thereof, a source of direct neto ignition system comprising a circuit breaker connected in series with the primary winding and in series with the said source, and operating in one position to break the alternating current circult and to send current from the said source through the primary winding, and in the other position to make the alternating current circuit and .to send current from the said source to ground whereby the primary winding is repeatedly supplied with booster current at times regulated by the circuit breaker.

' .HARRY A. BRINSON.