US2450524A - Starting and ignition system - Google Patents

Description

Oct. 5, 1948.

c. w. ROOT ,450,524 STARTING AND IGNITION SYSTEM Filed June 8, 1944 I 'l a" AL 75m 56 MHZZZ; INVENTOR. j? 4% M M Patented Oct. 5, 1948 STARTING AND IGNITION SYSTEM Charles W. Root, Sidney, N. Y., assigno'r to Bendix Aviation Corporation, New York, N. Y., a

corporation of Delaware Application June 8, 1944, Serial No. 539,335

11 Claims.

tom in a novel manner whereby simplicity as well as improved efiiciency are obtainable.

Still another object is to provide a novel ignition system wherein a single induction coil is employed as a switch operating relay and as means for stepping up the voltage from a low voltage source.

A further object is to provide novel means for taking the place of or supplementing the output of a magneto generator when the latter is 0perated at speeds too low for rendering the same otherwise eifective.

A still further object is to provide novel means for supplying the necessary energy in the ignition system of an internal combustion engine, or the like, which means is operable independently of the speed of the engine.

Another object is to provide a novel booster ignition system wherein vibrating contact points are eliminated together with the necessity for keeping such points properly adjusted and in satisfactory operating condition.

Another object is to provide a novel ignition system wherein a single cam operated circuit breaker is employed for controlling both the main source of electrical energy and the booster or starting source.

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

In the drawings wherein like reference characters refer to like parts throughout the several views,

Fig. 1 is a diagrammatic illustration showing how the present invention may be incorporated in a high voltage distribution ignition system wherein a magneto generator is employed as the main 2 source of electrical energy for normal operation of the engine; and

Fig. 2 is a partialsimilar view showing how the invention may be adapted to a low voltage distribution system.

In the embodiments shown, by way of example, in the accompanying drawings, the invention is illustrated in combination with an ignition system for a six-cylinder engine, wherein the source of energy during normal operation is in the form of a magneto generator M. The latter, as shown in Fig. 1, embodies an ignition coil or transformer 5 which consists of a primary winding 6 and a secondary winding '7. One end of winding 6 is periodically connected to ground at B through a circuit breaker 9 which may be of any suitable known type. The points or contacts of the circuit breaker are normally biased to closed or contact position by any suitable resilient means, such as a spring i9, and a rotating cam H is provided for periodically separating said contacts. The other end of primary winding 6 and the low voltage end of secondary winding 1 are permanently connected to ground at i2. The high potential end of secondary winding l is connected to the rotating arm M of a suitable ignition distributor [5 whereby the high voltage output of the magneto is distributed through a plurality of circularly arranged distributor contacts Hi to the spark plugs il in the cylinders of the engine. One side of the spark gap of each spark plug is connected to a distributor terminal iii and the other side is connected to ground at 8.

In the familiar circuit described above, current may be generated in primary winding 6 through the medium of any one of many well-known magnetic systems, such as by a magnetic rotor (not shown) capable of periodically causing a reversal or change of magnetic flux in a core it around which windings E5 and i may be wound. Since many of such magnetic systems are familiar to all skilled artisans and since the same, per se, does not constitute a part of the present invention, it is believed to be unnecessary to illustrate and further describe the same.

As is well known in the art, when the current generated in winding 6 is at about its maximum value, the primary circuit, which includes coil 5 and circuit breaker 9 is suddenly interrupted by the opening of the contacts of the circuit breaker by cam il. This results in a sudden cessation of current flow in coil 6 and, hence, a collapse of the surrounding magnetic field, thereby inducing current flow at a relatively high voltage in the secondary winding 1 and, hence, across the gap of a spark plug 11. The particular spark plug is determined each time by the position of distributor arm I4 at that particular moment. To minimize sparking at the points of the circuit breaker, a condenser may be connected in shunt therewith. A condenser having a capacity of about .25 micro-farads is satisfactory.

An ignition switch 2| may be provided for connecting winding 6 to ground at 22 forthe purpose of rendering the magneto ineffective for firing the spark plugs. tion, winding 6 will be permanently connected to ground at 22, thereby preventing any suiiiciently rapid changes of current in said-winding-toinduce the necessary voltage in winding- I;

For starting an engine on which the above-described ignition system is installed, any'suitable means such as a starting motor 23 having a field winding 25 may be employed for turning the crankshaft. The starting motor may be energized' by a battery 28- through a switch 21. In modern installations, a battery having a rated voltage of. about twenty-four volts isordinarily used; If desired, means may be provided for. automatically opening switch 21 when the engine starts-and picks up speed.

Since a starting motor, or the like; of the type ordinarily'used on modern engines is unable. to turn the engine crankshaft and, hence, the magneto rotor at a-sufiiciently high speedto render the magneto effective for. firing the spark plugs, novel means are provided for supplementing or taking the. place of themagneto in the. ignition system to supply the necessary electrical. energy for starting the engine. As shown, said means comprises a-combined self-induction booster and relay coil 28 wound on a metallic core 29. A movable contact carrying arm 3ll'which may be electrically conductive is shown as. being pivotally or the equivalent thereof; mounted thereon andadaptedto engage: stationary. contacts 34' and 36, respectively. Contact 33t-isyieldably maintained inengagement with contact 34 by spring 32 and contact 3S'is engageable by contact 35 when armature'30-is. attracted" by the solenoid or electromagnet 28; 29? The other end of coil28is conn'ected to a'suitable source of electrical energy and in the illustrated embodiment is connected to battery 25- in series with switch 21 and in parallel with'starting motor 23; 25.

of magneto M in such a manner as to place primary winding S'and circuit breaker 9'in parallel with respect to battery 25 or booster coil 28 and, in the form shown, is connected at a point between ignition switch 2| and winding 6;

When it is desiredto start an engine on which the above-described system is mounted, ignition switch 2| is opened and starting switch 21 is moved to closed position. Electrical current thenfiows'from battery 26 to starting motor 23, 25*

for rendering the latter operable to crank the engine. Current from the battery also flows through'coil 23 armature 3'0 and contacts 33, 34'

When this switch is in closed posi- Contact 36 is electrically connected to the primary circuit to ground at 31. The flow of current through coil 28 sets up a magnetic field which is effective to attract armature 3E) in a counter-clockwise direction to core 29, thereby separating contacts 33, 34 and moving contact 35 into engagement with contact 36. During this movement of arm 36, the circuit through coil 28 is momentarily interrupted but the. interruption is of insuificient duration to permit the arm'to be pulled back to the illustrated position by spring 32. If desired, a so-called shaded armature, i. e., an armature withone or more turns of wire 39 thereon, may be employed. This short circuiting turn causes alag inthecollapsing of the flux and, hence, insures against any release of the armature.

Uponthe engagement of contact 35 with contact 36; a circuit is completed from battery 26 through coil 23 to the parallel connected primary winding: Band circuit breaker 9. The flow of current in this circuit is. continuous so that the electromagnetic relay 28',v 29 is continuously elfective to hold armature 3%) toward the left as viewed: in the drawings and, hence, hold contacts 35 and 36 in engagement. Thus, when the pointsof circuit breaker 9 are in closed or engaged position, at least the major portion of the current flowing in said circuit follows the path of least resistance, i; e., through the circuit breaker 9 to ground at 8. Each time the circuit breaker V points are separated byrotating cam l l. the current from the battery can then flow only through primary-winding 6; There is accordingly a sudden rush or surge of current through said windingeach time that the circuit breaker contacts :are separated. The electrical constants of the various circuits maybe so chosen that the cur- 7 rent in primary winding 6 increases suddenly from zero amperes to approximately 6 amperes whenever the circuit breaker is operated.

By reason of the fact that the minimum resistance of the above-described circuit, including battery" 26- and coil 28, is substantially increased when circuit breaker 9 opens, there is a slight but suddenzdrop in the current flow. This sudden slight decrease of current flowing in coil 28 results-by reason-of the self-inductance of the coil in a sudden increaseof voltage; This voltage rise enhances the suddenness of: the current rise in primary winding G and, hence, the suddenness of the changein magnetic flux surrounding said winding and: winding. 1. This change of' magnetic flux is sufiiciently rapid to induce in secondary winding 1 a. sufliciently high voltage to create a spark across. the gap of the spark plug l 1, then in circuit therewith. The periodic surges throughprir'nary winding 6 and, hence, the creation of sparks at' the: spark plugs ar roperly timed by the operation of circuit breaker 9 and are accordingly directive to start the engine. As soon as the speed ofthe engine is'high enough to. drive-the magneto rotor at a suitable operating speed; starting switch 2Tis either manually or automatically opened in any well known manner. Coil 28 is thus disconnected from its source of energy and being'thus de-energized is no longer capableof subjecting armature 38 to an electromagneticpull'. The armature isaccordingly moved back to the illustrated position by spring 32 or other equivalent means, thereby completely disconnecting theentire starting system from the main ignition system.

I'n'onesuccessful embodiment of the invention, a standard type of a well known make of magneto, wherein the primary: winding had a resistance of approximately .31 ohm and an inductance of art.

about 1.9 milli-henries, and a 24-volt battery were employed as the sources of electrical energy. The magneto circuit breaker oiiered a negligible resistance of not more than .02 ohm and the coil 28 in said system comprised 1800 ampere turns, the average current therethrough being approximately 6 ampere's. In this system, the voltage upon the opening of circuit breaker 9 increased from battery voltage to approximately 200 volts by reason of the self-induction of coil 28. With an armature 30 weighing approximately IOgrams, a spring 32 having a pull of about 5 ounces was used. The electromagnetic pull exerted by solenoid 28, 29 on armature 3!! was approximately 2 pounds. If necessary or desirable, a resistance 38 may be included in the circuit for limiting the current which flows through primary winding 6 during the starting operation to a value which will not be detrimental to the magneto or other component of the circuit.

The above-described booster or starting system may also be employed in combination with a low voltage distribution ignition system (Fig. 2) wherein the magneto has only a low voltage induction coil 6a in lieu of transformer 6, l, the energy from said coil being distributed through a suitable low voltage distributor 40 to a plurality of transformer coils 4! each of which comprises a primary winding 42 connected, to a distributor terminal 43 and a secondary winding 44 operatively connected with the insulated terminal of a spark plug [1. The current is distributed to contacts 3 through a rotating arm 45 which carries a brush 46 that has yielding sliding contact with said contacts. The booster system of Fig. 1- may be connected directly to thelow volt-age distributor and, hence, feed the individual transformer coils ll in the same manner that it feeds coil 6, l of the first embodiment, circuit breaker 9 acting as the timing control means. When the present booster system is so used it is preferable, although not necessary, that the rotating brush 46 of the distributor be capable of bridging the gap between successive distributor terminals 63 so there will never be any breaking or interruption of the starting circuit at the distributor. This is desirable to prevent the possibility of armature 33 being withdrawn from the solenoid by spring 32 or other equivalent means during the starting operation.

If desired, a filtering condenser 41 may be pr vided in the booster uni-t or elsewhere. Such a condenser will filter out any radio frequency impulses which might be generated in the magneto and which might otherwise be fed back into or through the battery and cause radio interference by being fed into other circuits connected with the battery.

Although only a limited number of embodiments of the invention have been illustrated and described in the drawing and in the foregoing specification, it is to be expressly understood that the same is not limited thereto. Various changes may be made, for example, in the specific electrical connections, in the specific electrical constants, and in the specific structure and arrangement of the parts illustrated and mentioned, by way of example, without departing from the spirit and scope of the invention as the same will now be understood by those skilled in the For a definition of the limits of the invention, reference is had primarily to the appended claims.

What is claimed is:

1.-In an ignition system for an internal combustion engine, a magneto generator having an ignition coil comprising a primary winding, a circuit breaker connected across said winding, means for periodically opening said circuit breaker, a source of electrical energy, a motor, a solenoid comprising an induction coil, means including a switch connecting said motor and one end of said induction coil to said source, an armature movable by said solenoid when the latter is energized by said'source, a pair of contacts movable with said armature, means connecting said contacts with the other end of said induction coil, a stationary contact connected to ground and adapted to be engaged by one of said movable contacts, resilient means for normally holding said last-named cont-acts in engagement to close a circuit containing said induction coil and said source, a second stationary contact engageable by the other of said movable contacts when said armature is electr-omagnetically attracted by said solenoid, and means for connecting said second stationary contact to the ungrounded end of said primary winding.

2. In an ignition system for an internal combustion engine, a magneto generator having an ignition coil comprising a primary winding, a circuit breaker connected across said winding, one end of said winding and one side of said circuit breaker being connected to ground, means for periodically opening said circuit breaker, a source of uni-directional electrical energy, a motor, a solenoid comprising an induction coil, means including a switch connecting said motor and one end of said induction coil to the ungrounded terminal of said source, an armature movable by said solenoid when the latter is energized by said source, means for electrically connecting said armature to the other end of said induction coil, a contact connected to ground and adapted to be engaged by said armature for completing a circuit containing said induction coil and said source when said switch is in closed position, a second contact engageable by said armature when the latter is attracted away from u said first contact by said solenoid, and means for connecting said second contact to the ungrounded end of said primary winding.

3. In an ignition system for an internal combustion engine, an ignition coil comprising primary and secondary windings, a circuit breaker connected in parallel with said primary winding, means for periodically opening said circuit breaker, a source of electrical energy, a motor, a solenoid comprising an induction coil, means for connecting said motor and one end of said induction coil to said source, an armature movable by said solenoid when the latter is energized by said source, means for electrically connecting the other end of said induction coil to said armature, means norm-ally engaged by said armature for connecting said other end of the induc tion coil to the other terminal of said source, means connected to one end of said primary winding and engageable by said armature for connecting said other end of the induction coil to said primary winding when the armature is electromagnetically attracted by said solenoid, and means operatively connecting the other end of said primary winding to said other terminal of said source.

4. In an ignition system for an internal combustion engine, an ignition coil comprising a primary winding, a circuit breaker connected in parallel with said winding, means for periodical- 1y opening said circuit breaker, a source of elec- .ctrical energy, ..-.a amotor, means ,openatively connecting one end:.oi said primary winding toa terminal of said source, and means jfor connectingthe-t other end. of .said primary winding to the other-terminal of said source, said 1ast-named means comprising a solenoid including an induction-coil, means including-aswitchfor connecting said motor and one end ofsa-id induction 'QOil.tO.;S3fiid other terminal of the source, and an armature operable by said solenoid when the latter=is energized by said source, said armature being-adapted to normally connect the other end .of said induction coil to said oneterminal of the source and-to connect-said other end of said induction coil to said other end of the primary Winding when said armature is electromagneticallyzattracted by said solenoid.

.5. In an ignition systemfor an internal combustion engine, an ignition coil comprising a primary winding, a source of electrical energy, a motor operable thereby, means for connecting one end of said primary winding to one terminal of said source, said means comprising a solenoid including an induction coil, an armature electromagnetically operable by said induction coil for connecting one end of said induction coil to said winding and means including a switch for connecting the motor and the other end of said induction coil to said one terminal, means operatively connected to the other terminal of said source, said armature being operable to disconnect said induction coil and primary winding and to connect said last-named means to said induction coil for connecting the latter and said other terminal of said source when said solenoid is deenergized, and means operatively connecting the other end of said primary winding with said other terminal of the source.

6. In an ignition system for an internal combustion engine, a motor, a plurality of ignition coils, each comprising a primary winding, an ignition distributor comprising a plurality of circularly arranged contacts'and a revolving brush adapted to successively engage said contacts, said brush being adapted to simultaneously engage successive contacts, means connecting each of said contacts to one of said primary windings, a source of electrical energy, means for connecting said brush to one terminal of said source, said means comprising a solenoid including an induction coil, means for connecting said motor and one end of said induction coil to said terminal, anarmature adapted to normally connect the otherend of said induction coil to the other terminal of said source and means engageable by said armature when said solenoid is energized for connecting said otherendof the induction coil to said brush, circuitbreaker means for diverting current from said source away from said brush,

means for periodically opening said circuit breaker means, and means operatively connecting the other ends of said primary windings to said other terminal of the source.

'7. In ignition apparatus, a source of uni-directional electrical current, a'solenoid including an inductance adapted to be electrically connected at one end to a terminal of said source, circuit breakermeans, means for selectively connecting the-other end of said inductance either to the other terminal of .said source or to one side of a circuit breaker, said means comprising an armature adapted to be electromagnetically actuated by said solenoid when the latter is energized, the other side of said circuit breaker being operatively connected to said other terminal of the source, an ignition coil having the primary winding thereof connected in parallel with'said circuit breaker, 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 when the latter is in closed position, means for periodically actuating said circuit breaker to open position, and a spark gap in series with the second winding of said ignition coil.

8. In an ignition system, a magneto generator wherein electrical current at relatively high voltage is induced in a secondary circuit when aicircuit breaker is actuated to interrupt the flow of current induced in a primary circuit by magnetic means, a source of uni-directional current, means for connecting said primary circuit to the ungrounded terminal of said source, said connecting means including a solenoid comprising an induction coil, means for connecting one end of said induction coil to said source and an armature operable by said solenoid when the latter is energized for completing a connection between the other end of said induction coil and said primary circuit, said armature being adapted to normally open said connection and connect said other end of the induction coil to the grounded terminal of said source, and'means operatively connecting said primary circuit to the grounded terminal of said source.

9. In an ignition system for an internal combustion engine, an ignition coil comprising a primary winding, a source of electrical energy, a circuit breaker connected in parallel with said primary winding, means for periodically opening said circuit breaker, a solenoid including an induction coil, means for connecting one end of said induction coil to a terminal of said source, means including an armature electromagnetically operable by said solenoid for normally effectinga connection between the other terminal ofsaid source and the other end of said induction coil when the latter is de-energized and for interrupting'said connection and efiecting a connection between one end of said primary winding and said other end of the induction coil when the latter is energized, and means connecting the other end of said primary winding to the other terminal of the source.

10. In an ignition system for an internal combustion'engine, a motor, an ignition coil comprising a primary winding, circuit breaker means connected in parallel with said primary winding, means for periodically opening said circuit breaker means, a source of electrical energy, a solenoid comprising an induction coil, means for connecting said motor and-said induction coil in a circuit with said source at the will of the operator, and means eiectromagnetically operable by said solenoid for opening said-circuit and closing a circuit including said source, induction coil, and primary winding in series whenever said solenoid is energized.

11. In an ignitionsystem for an internal combustion engine, a plurality of ignition coils, each comprising a primary winding, an ignition distributor comprising a plurality of circularly arranged contacts and a revolving brush adapted to successively engage said contacts, said brush being adapted to simultaneously engage successive contacts, means connecting each of said contacts to one of said primary windings, a source of electrical energy, a solenoid comprising an induction coil, means for connecting said induction coil in a circuit with saidsource at the will 9 of an operator, and means electromagnetically operated by said solenoid for opening said circuit and closing a circuit including said source, induction coil, and brush in series whenever said solenoid is energized.

CHARLES W. ROOT.

REFERENCES CITED The following references are of record in the file of this patent:

Number UNITED STATES PATENTS Name Date Honold Jan. 5, 1915 Lepel Nov. 27, 1928 Lepel Sept. 16, 1930 Hartzell June 14, 1932

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