US1531389A - Flux control for magnetos - Google Patents

Description

March 31,. 1925. 1,531,389

H. H. GORDON FLUX CONTROL FOR MAGNETOS Filed Nov. 20, 197117 Patented Mar. 31, 1925i. e

UNIT-ED sTArEsPArENT OFFICE.

HAYNER H. GORDON, OF WASHINGTON, DISTRICT OF COLUMBIA, ASSIGNOR, BY MESNE ASSIGNMENTS, TO THE ELECTRIC AUTO-LITE COMPANY, OF TOLEDO, OHIO, A COR- PORATION OF OHIO.

FLUX CONTROL non. M AGNETos.

' Application led November20, 1917. Serial Io. 203,027.

To all whom t may concern:

Be itV known that I, HAYNER H. GORDON, a citizen of the United States of America, residing at Washington, in the District of Columbia, have made newv and useful Improvements in Flux Controls for Magnetos, of which the following is a full and complete specification, reference being had to the accompanying drawings, which form -part of the specification.

This invention relates broadly to structure V`in which an electric current is generated, or set up in a winding by subjecting the same to a variation in magnetic flux, and relates vmore particularly to the provision of means for regulating the rate of flux change independently of the means\that produces the ux change.

This invention also relates more particu# larly to high tension magnetos of the type which comprise a high tension winding and a low tension or choke winding, superimposed upon a core which is subjected to a variable magneto motive force. The varia- 5 tion in the magneto motive force is produced by either rotating the core carrying windings in a magnetic field, or else by the use of a magnetized rotor operating in conjunction with a fixed core and pole piece. In either case, a iux change isset up in the core, which change has a variable rate which approaches a sharp maximum twice each revolution of the rotor or core in the two pole magnetos, which flux change however, is opposed by the choke winding, which is normally short circuited and which, as soon as a iux change tends to take place in the core, sets up a counter magneto motive force, which tends to resist such change. At points 4Q of maximum rate of flux change however, the choke winding circuit is suddenly opened by some external means, such as a clrcuit breaker, and the hitherto repressed `iuX change is allowed to take place in the core, thereby setting up a potential in the high tension winding with a consequent breaking down of the spark gap to which the high tension windin is connected. The spark thus formed contlnues to burn in the form of an arc, for the breaking down of the spark gap has closed the high tension winding or circuit, and the current flowing in this winding has a -re,f. ;ulative action upon the fiux change taking place in the core.

This type Aof magneto operates very satisfactorily at low or no'rmal engine` speeds, but when operated at the extremely high speed demanded in the modern eightpor twelve Cylinder motors, the intensity of the flux change becomes so great 'as to cause overheating from eddy currents set up in the magnetic core structure and from the high current density in the short circuited choke winding. Also in a magneto which is designed to give a good spark at starting when rotated at the extremely high speed demanded, the spark becomes so hot that the sparking points of plugs are soon burned away, or become overheated causing pre-ignition and in addition the counter magneto motive force set up by the choke windings at extremely high speed causes serious complications in the armature reaction of the magneto. This same action is also present'in the low tension magneto, such as is used in make and break ignition, the structure of this type of magneto being similar to that just described, with the exception that no secondary winding is used, the low tension or choke winding being directly connected to the spark producing electrodes. It is the general object of this invention to provide a magneto structure in which the rate of iux change through a current producing winding may be controlled independently of the means which produces such flux change` It is a further object of this invention to provide a magnetic leakage path around a current producing winding,the magnetic reluctance of said path being capable of automatic variation in accordance with the character and periodicity of the current prol duced in the winding. y

It is a further object of this invention to provide a magneticA leakage path around a current producing winding, the magnetic reluctance of said path being capable of automatic variation in accordance with the phasev relationship between the `current impulses set up in the current producing winding, and the means for causing a flux change to take place in the winding. p

It is a still further obj ect of this invention to provide a magneto which may be operated satlsfactorily at high speeds without excessive heating and excessive armature reaction.

Further objects of this invention will appear from the following disclosure.

. For the purpose of rendering this inventionv more clear reference is had to the accompanying drawings, in which Figs. 1 and 2 show one embodiment of the in vention as applied to amagneto of the rotating coil type and Figs. 3, 4: and 5`show another embodiment of the invention as applied to a magneto of the inductor type.

In the form shown in Fig. 1, a permanent magnet 1 is provided with pole pieces between which revolves a laminated armature 3 carrying the choke winding 4 and the secondary winding 5, the secondary being connected to a distributor or to plugs by a lead 6 while the low tension winding, one end of which is grounded, is` connected to a circuit breaker 7 by alead 8. Mounted in the limbs of .the magnet 1 are .two projections 9 and 10, the projection 9k being adjustable by means of the screw driver slot 11 and the lock nut 12 while the 4 projection 10 is adjustable by means of the crank 13, these projections forming a magnetic leakage or shunt path for the magnetic iiuX.

The crank 13 may be manually operated but is preferably yconnected to some form of automaticv governor so that thev position of the projection 10 may be automaticallyj controlled by the speed of the engine. At low speeds and for starting, the member 10 is in the position indicated by full lines in Fig. 1 while at high speeds the .same is advanced into the dotted line position. Itn is thereby readily seen that the members 9 and 10 form a` shunt path of variable magnetic resistance, the proportions of which may be so designed as to enable the magneto to produce 'sparks having a fixed energy value throughout the range of speed at which thev magneto is operated, more or less of `the magnetic iiux leaking across the path provided by the projections 9 and 10 at higher speed.

Fig. 2 shows a slight modification of this structure in connection with the same type of magneto. The usual interrupter mechanism is enclosed in the adjustable casing 14, which is controlled by the rod 15 which is connected to any suitable form of spark regulative mechanism. Simultaneously movable by the rod 15 is al rod 16 connected to an arm 17 carried upon a pivot shaft 18 mounted in turn upon a plate 19, which is fastened by suitable means to the magnet. An arc shaped piece of 'soft iron l20 is also fastened to the shaft 18. As the timer is advanced into an earlier s ark position by the upward movement o the rod.

15, which may be controlled either manually or by some type of governing device actuated bythe engine, the piece 20 is swung down into the dotted line position by means H of the rod 16, thereby providing a magnetic l shunt path of more or less reluctance, the reluctance of the same decreasing as the timerA is advanced in accordance with the increase in speed of the motor.

In certain types of magnetos the primary and secondary windings are located upon a-coil supporting structure and a variable magnetic `flux is supplied thereto by means of a rotating polarized inductor. In. such types of magneto the coil supporting structure is usually angularly movable about the axis of rotation of the inductor shaft and carries fastened' thereto, the interrupter mechanism for the choke winding. By such an arrangement the coil supporting means is angularly moved together with the inin which 21 represents a coil carrying the usual choke and secondary windings supported by the pole pieces 22 and 23 between which the inductor 24.1fotates. In Fig. 3 the full lines represent the position of the coil supporting structure when the spark is fully retardedfor starting and the dotted lines represent the position which the coil supporting structure assumes when the spark is fully advanced. A crotch shapedy memberf25 is iixedly supported at one side of the coil supporting structure, the same being shown in plan view in Fig. 4. It will be seen that as the coil su porting strc- 'ture assumes the advanced spark position shown in the dotted lines in Fig. 3 that the -same will lie more or less inside of the crotch shaped member 25 which therefore provides a magnetic leakage path of more or less magnetic resistance.

Fig. 5 shows a furthermodication of this structure in which a stationary member 26 is fastened between the polar projections 22 and 23. It will be evident that as the coil supporting structure is rotated to the left for thel advanced spark position that the circular polar base 23' will a proach the en d" of the fixed member 26 which thereby provides a variable magnetic shunt path.

' 7While permanent magniets are shown in all the figures as a'source of magnetic energy it is, of course, obvious that electromagnets could be used for this purpose without departing from the spirit of the invention.

What I claim is:

1. In an ignition system forsinter-nal combustion englnes, means for generating `a high tension currenuncluding a core hav:

las

ing thereon a winding, means to produce a change of magnetic ilux in said core to produce a current in said winding, a magnetic leakage path to shunt a part of the magneticdlux around said winding, and means for automatically varying the reluctance of said leakage path in accordance a magnetic leakage path with the speed of the engine.

2. In an ignition system for an internal combustion engine, a spark producing winding mounted upon acore, means operated by the engine for causing a periodic IuX change in said core to energize said winding also ysubjected to periodic flux change for controlling the rate of flux change in said core, and means for decreasing the' reluctance of said leakage path as the periodicity of flux change increases. e

3. In a magneto, the combination of a source ofimagnetic flux, parallel paths therefor, mea-ns in one of said paths tor generating an igniting current, and means varying the ratio of magnetic iux in the two paths.

4. In a magneto, the combination with a source of magneticeenergy of a core, means for generating a currentJ comprising a high tension winding and a choke winding, a circuit interrupter connected in circuit with said choke winding, means to advance and retard the time of functioning of said circuit interru'ptr relative to a fixed point in the time cycleof the magneto, and means to simultanously adjust the reluctance of av magnetic leakage path for shunting a por- -tion of the magnetic uX around said core.

5. In a magneto, the combination with a current producingwinding' ot a means for producing a flux change insaid winding, timing mechanismto. adj ustthe time of suchV flux change relative'to a ixed point in the time cycle [of the `I'nagnetowa magneticv leakage patlnto shunt a portion ofthe magnetic flux outside of said current producing winding, and means to adjust said spark timing mechanism and simultaneously controlhthe magnetic reluctance of said leakage pat c Y 6. In a high `tension magneto, the combination rwlth a spark producing winding of rotating means for producing a flux change in said winding, timing mechanism whereby the time of functioning of said spark producing winding may be determined, supplemental means for controlling the rate of e iux change in said winding independently of the speed at which the magneto is operated, and means for simultanously adjusting said timing mechanism and varying the magnetic reluctance of said supplemental means for controlling'the rate oflux change` in said winding.

7. In a system for the production of energy, the combination with an internal combustion engine, of a magneto comprising a source ofmagnetic energy, a

'f core, means for generating a current comprising windings upon said"core, means for producing a variable magnetic flux in said corer said means being actuated by said engine and a magnetic leakage path'for shunting a port-ion of the magnetic flux outside of said current producing windings, the reluctance of said magnetic leakage pathbeingicontrolled vby the speed of the engine.

8./In an ignition system for an internal combustion engine, a spark producing winding mounted upon a core, means operated by the engine for causing a periodicux change' in said core to energize said winding, a magnetic leakage path also subjected to the periodic iuX change for controllingthe rate of flux change in said core, and means for .automatically decreasing the reluctance of said leakage path as the. periodicity kof `flux change increases.

9. In an ignition systemfor an internal combustion engine, a spark plug, a highl tenset my hand. f

HAYNER H. IGrRDl\T

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