US2272625A - Ignition means - Google Patents

Description

Feb. 10, 1942. w. J. SPENGLER ET AL 2,272,625

IGNITION MEANS Filed Oct. 26, 1959 2 Sheets-Sheet 2 a if T7 fiFZ 75 2 56 75 INVENTORS Wm .sgm 052m fflmwq ATTORNEY.

Patented Feb. 10, 1942 IGNITION MEANS .i'alter J. Spengler, Jakob n. Frei, and Glen n. Dingman, Sidney, N. Y., assignors to Bendix Aviation Corporation, South Bend, Ind., a corporation of Delaware Application October 26, 1939, Serial No. 301,357

14 Claims.

This invention relates to ignition apparatus and more particularly to an ignition system and a magneto-generator therefor adapted for use on internal combustion engines.

One of the objects of the present invention is to provide a novel ignition system for an internal combustion engine wherein the current is distributed through at least a major portion thereof at low voltage.

Another object of the invention is to provide a novel magneto-generator which is adapted for use in the ignition system of an internal combustion engine wherein low tension current distribution is employed.

Still another object is to provide a novel ignition distribution system wherein electrical losses are reduced to a minimum and wherein failures due to flash-overs, particularly at high altitudes, are effectively eliminated.

A further object is to provide a novel ignition distribution system for multi-cylinder internal combustion engines wherein long high tension cables are eliminated, thereby obviating inherent electrical losses which are inevitable during the transmission of high tension current through long cables and materially reducing the fire hazard occasioned by ruptured high tension leads.

A still further object is to provide a novel magneto generator adapted for use in a low tension distribution ignition system which is so constructed as to effectively prevent the entrance of moisture, dust and other particles of foreign matter.

Another object is to provide a novel ignition distribution system which requires a minimum of radio shielding to eliminate interference by electrical radiations therefrom with radio reception in nearby receiving sets.

Another object is to provide an ignition system for multi-cylinder internal combustion engines which is so constructed that the circuit breakers therein will not be over-taxed at high speeds.

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 to define the limits of the invention, reference being primarily had for this latter purpose -to the appended claims.

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

Fig. l is a side elevation, partly in section and with parts broken away, of one novel form of magneto which may be employed in carrying out the present invention;

Fig. 2 is a top plan view of said magneto, partly in section and with parts'broken away;

Fig. 3 is a transverse sectional view taken substantially on line 3-3 of Fig. 2 and showing one form of novel distributor circuit-breaker mechanism comprehended by the invention;

Fig. 4 is a detail side elevation, with parts broken away, of the cam employed in said magneto;

Fig. 5 is an enlarged end view of said cam as viewed from the right in Fig. 4;

- Fig. 6 is a still further enlarged end view of a portion of said cam; and,

Fig. 7 is a diagrammatic illustration of one form of the novel ignition distribution system comprehended by the present invention.

Only one embodiment of the invention is illustrated, by way of example, in the accompanying drawings in a form adapted for use in an eight cylinder, four-stroke cycle internal combustion engine. In the form shown, alternating low tension current is generated by a magneto-generator and the current impulses are distributed in timed relation and in predetermined sequence to spark plugs in a plurality of engine cylinders. Said distribution is accomplished through the medium of a plurality of parallel connected circuits, equal in number to the number of engine cylinders to be served and each including a single circuit breaker operated in conjunction with the rotor of .the magneto-generator. Each of said circuits also includes a separate ignition or step-up transformer coil located near the spark plug served thereby.

The novel form of magneto-generator illustrated in the drawings comprises a casing which includes a main casing member l0 that is supplemented by a front cover plate ii, a terminal cap or top cover l2, and a rear plate l3. Rotatably supported in casing H), H by any suitable means, such as ball bearings l4, I5, is a four-pole magnetic rotor I G. The forward end of rotor shaft ll extends outwardly beyond front cover plate I l and may be drivably connected, in any manner well understood in the art, to the crank shaft or other suitable part of an internal combustion engine (not shown). Above rotor IS, a low tension coil it having a laminated core I9 is supported on the upper ends of a pair of laminated pole pieces 20, 20, only portions of which are shown, that cooperate in a known manner with through the coil for generating alternating cur- 4 rent therein.

In the form illustrated in the drawings, the current impulses generated in coll l8 are distributed to the spark plugs of an engine through a novelly constructed circuit breaker and distributor mechanism. Said mechanism is removably and adjustably mounted in a novel manner on rear plate l3 of the magneto casing for operation in conjunction with rotor I, the same comprising a supporting member or frame-like structure 2| which is provided with a plate portion 22 that slidably engages the outer face of rear plate i3 and has a projecting annular guide or pilot 23 which slidably fits into a circular opening l3 in said rear plate. Member 2| is yieldably secured in position against plate I3 by means of a plurality of screws 24 (Pig. 3) and cooperating springs 25 (Fig. 1). The outer ends of screws 24 threadedly engage plate I3 and are provided with enlarged, unthreaded portions 25 which slidably extend through the narrow portions 21 of differential arcuate grooves in plate portion 22'. In the wider portions 23 of said grooves, springs 25 surround the enlarged portions 26 of screws 24 and expand against the heads of said screws and plate portion 22, thereby tending to hold the latter against rear plate l3.

Formed integrally with and projecting rearwardly from plate portion 22, i. e., to the right as viewed in Fig. 1, is a frame-like structure comprising upper and lower arms 29 and 3|), respectively, which are joined at their outer ends by a vertical portion 3|. The lat tr supports 'a short stub shaft 32 which in turn rotatably supports the hollow end of a cylindrical cam member 33 by means of a roller bearing 34. The opposite end of said cam member is provided with a shaft portion 35 which is supported in a roller bearing 35 and extends into magneto housing l0, l3 in concentric relation with opening l3 in plate I3. A gear 31, which meshes with a smaller gear 38 on rotor shaft I1, is secured to the forward end of shaft 35 for rotation therewith. In the embodiment shown gears 31 and 38 are so proportloned that cam 33 will be driven at one half the speed of rotor l6. For a purpose which will more fully appear hereinafter the outer surface of cam member 33 is provided with four axially and circumferentially spaced flats 39A to 39D, the surfaces between opposite edges of each of said flats constituting cam lobes for holding circuit breakers, to be hereinafter described, in open position. Each of the flats 33A to 33!) is rounded off at each end. such as indicated at 39 (Fig. 6) to insure smoother operation of the circuit breakers to be hereinafter described.

Mounted above and secured to frame portion 29 is a block 4|! of insulating material on which is adjustably scoured eight angle shaped contact supporting bars 4|, one arm of each of said bars extending downwardly over the edge of said block and carrying a stationary contact 42 (Fig. 3). Bars 4|, as shown, are secured in position, four at one side of block 4|! and four directly opposite at the other side thereof by any suitable means, such as bolts 43, which serve also as electrical terminals. Bolts 43 are anchored in block 4|! and extend through elongated slots 4| in bars 4| (Fig. 2), thereby rendering the latter adjustable. It will be understood that the number of contacts 4|, 42 in any particular device will depend upon the number of engine cylinders to be served, the number of contacts being equal to the number of cylinders tobe served.

Mounted below frame arm 30 and insulated therefrom by insulating washers 44, 45 and sleeves 46 around the securing bolts 41 is a metallic bus bar 48 to which is electrically connected eight metallic strips 49. Each of the latter supports a resilient arm 50 carrying a contact point 5| on the free end thereof for engagement, with a contact point 42, and a cooperating cam follower 52 mounted on a resilient arm 53, a piece of oil-soaked felt 54 or the like being interposed between parts 52 and 53 for lubrication purposes. Resilient arm 53 yieldably holds follower 52 against cam 33 and arm 50 urges contact 5| toward one of the stationary contacts 42. The novel construction of the circuit breakers is more fully described and claimed in a copending application of Walter J. Spengler Serial No. 27,476.

Secured in position against the outer end of wall 3| by means of a strip 55 are eight small condensers 56, each of which is connected in parallel with a set of cooperating circuit breaker contact points 42, 5|. One side of each condenser 56 is connected by a conductor 51 to a terminal 43 and the other side thereof is connected to a corresponding breaker arm 50 through the condenser casing, strap 55 and bus bar 48, the condenser casings being insulated from wall 3| by an insulating plate 58. The upper end of strap 55 is secured to insulating block 40 by screws 59 and is accordingly wholly insulated from stationary contacts 4|, 42 and from ground.

Each of the terminals 43 is also connected by means of a conductor 60 to one of a plurality of outlet terminals 6| in cap l2, said conductors passing through tubes 62 extending through plate l3 and plate portion 22. Adjacent the terminals 43, conductors 51 and 60 are grouped together in tubes 53 to prevent excessive vibration thereof. Bus bar 48 and. hence, each of the contact points 5| are connected to the un-- grounded end of low tension coil 8 by means of conductors 64 and 65, the former of which passes through tube 62 for connection with the bus bar and both of which are connected to a terminal 66 that is adapted to be connected to ground externally of the magneto casing through an ignition switch 61 (Fig. '7).

The distributor and circuit breaker mechanism may be covered and protected from the elements by a suitable housing member. such as cup-like cover 68. The open end of said cover flts against the face of plate portion 22 and is provided with an external rib 69 complementary to a rib Hi on said plate portion. Cover 58 is firmly clamped to plate portion 22 by a clamp II which is V-shaped in cross section and engages the outer faces of ribs 69 and 10. The free ends of clamp H are secured together by a bolt 12 and a handle 73 is provided thereon whereby the entire breaker mechanism may be angularly adjusted about cam 33, within limits determined by the length of slots 21, 28, to vary the timing of the sparks in the engine cylinders.

Low tension current may thus be conducted from coil |8 through circuit breakers 42, 5| in predetermined sequence and thence to outlet terminals 6|. Each of the latter, as diagrammatically shown in Fig. 7, is connected by a lead 14 to the primary winding 15 of a transformer or ignition coil 15. The secondary winding 11 of each of said coils is connected, in practice,

by a relatively short cable I8 to the center electrode of a nearby spark plug IS. The other terminal of spark plug 19, as well as the opposite ends of windings l and 11, are connected in any suitable manner. to groundas at 80.

In the operation of the above-described ignition system and apparatus, rotor it of the magneto is rotatably driven by a suitable part of an internal combustion engine (notshown) thereby causing four reversals or magnetic flux through low tension coils l8, l9 during each revolution of the rotor and setting up an alternating current flow in the coil. With switch 61 in open position, the current thus generated is transmitted to bus bar 48 through cables 65 and 64 and thence through at least one of the circuit breakers 42, 5| to a primary winding of an induction coil 16. As shown, cam 33 has the flats 39A to 39D thereof so arranged that one pair of contact points 42, 5|, 1. e., the only pair in closed position, will be opened at approximately the same tim that a reversal of flux occurs in coil l8, I9, at which time the current flow in said coil and the winding 15 in circuit with the closed breaker points is at a maximum. Upon the opening of the circuit breaker the sudden drop of current in the particular winding 15 then in circuit results in the generation of a high tension voltage in the corresponding secondary winding 11 and accordingly causes a spark to jump across the terminals of a spark plug I9. Preferably, at' about the same time that one set of breaker points 42, 5| is thus opened to create an ignition spark in the above manner in one cylinder of the engine, another set of said contacts is permitted by the cam to move to closed position so that current from the magneto coil may build up in another ignition coil 16. All of the circuit breakers 42, 5| are thus opened and closed in a predetermined sequence and in timed relation for creating ignition sparks in the various cylinders of the engine. The timing of the sparks with respect to the positions of the pistons in the engine cylinders at the time the sparks occur may be varied by angularly shifting th breaker assembly with respect to cam 33 by manipulating handle 13.

There is thus provided a novel ignition distribution system for internal combustion engines and the like wherein current generated by a magneto-generator is distributed for the most structed magneto-generator embodying a novel combined circuit breaker and distributor unit for use in a system of the above character is provided. .The system and apparatus provided are particularly adapted for use in multi-cylinder, high-speed engines wherein a large number of sparks per unit of time are required and for use in aircraft engines at high altitudes for avoiding flash-overs due to the elimination of the high tension distributor. Simplicity in both construction and operation, as well as low cost in manufacture and maintenance, are also obtained with the present invention.

Although only a, single embodiment of the invention is illustrated and described in detail, it is to be expressly understood that the invention is not limited thereto. For example, the invention may be adapted to engines having a greater or lesser number of cylinders than indicated and to dual ignition engines. The specific construction of the magneto rotor and stator may also be altered in accordance with other structures of this character well-known in the art. If desired, both the low tension and high tension leads and terminals may be shielded in any well known manner to obviate interference thereby with radio reception. Various other changes may also be made in the design and arrangement of parts illustrated without departing from the spirit and scope of the invention, as will now be apparent to those skilled in the art. For a deflnition of the limits of the invention, reference is him primarily to the appended claims.

What is claimed is:

1. In an ignition system for internal combustion engines, a magneto comprising a coil and means for inducing alternating low-tension current therein, a plurality of ignition coils, each comprising a primary winding and a secondary winding, a plurality of circuit breakers, means connecting each one of said circuit breakers in series with a different one of said primary windings, means permitting an uninterrupted flow of electrical current connecting all of said circuit breakers to said magneto coil, and cam means for controlling the opening andclosing of said circuit breakers in predetermined sequence and in timed relation to each other.

2. In an ignition system for internal combustion engines, a magneto comprising a coil and means for inducing alternating low-tension current therein, a plurality of circuit breakers, means connecting one side of each of said circuit breakers to one terminal of said coil, a plurality of ignition coils, each comprising a primary winding and a secondary winding, means connecting the other side of each of saidcircuit breakers to a different one of said primary windings, cam means for effecting the opening and closing of said circuit breakers in predetermined sequence and in timed relation to one another and to the cycles of current flow in said magneto coil, said cam means being so constructed as to cause a different one of said circuit breakers to be closed and opened during each one-half cycle of said current flow, and means connecting the secondary winding of each of said ignition coils in circuit with an ignition device in the engine.

3. In an ignition system for internal combustion engines, a magneto comprising a coil and means for inducing alternating low-tension current therein, a plurality of ignition coils each comprising a primary winding and a secondary winding, a plurality of circuit breakers each comprising a stationary contact and a movable contact engageable therewith, a condenser connected across each of said circuit breakers, means for connecting each of said circuit breakers in series with a different one of said primary windings, said series circuits being connected in parallel with one another, means connecting all of said circuit breakers to one terminal of said magneto coil, said last-named connecting means permitting an uninterrupted flow of electrical current, and cam means for periodically actuating said circuit breakers in predetermined sequence, said cam means being effective to cause the opening of a different one of said circuit breakers each time the current in said first-named coil is at approximately its maximum value. v

4. In an ignition system for internal combustion engines, a magneto comprising a coil and means for inducing alternating low-tension current therein, a plurality of ignition coils each comprising a primary winding and a secondary winding, a plurality of circuit breakers, means connecting each of said circuit breakers in series with a'diiierent one oi! said primary windings, means for uninterruptedly connecting one side of each of said circuit breakers to said magneto coil during normal operation, and means for opening and closing said circuit breakers in predetermined sequence whereby said low-tension current flows through each of said primary windings in predetermined sequence, each oi! said circuit breakers being normally open but closed during an appreciable interval during each cycle of operation or the circuit breakers to permit a build-up of current in the primary winding in series therewith, said last-named means being so constructed as to effect the closing and opening oi only one of said circuit breakers during each one-half cycle of the alternating current ilow in said first-named coil, the opening of each circuit breaker being eilected when the value of the current flowing therethrough it approximately maximum.

5. In a magneto having means for inducing low-tension alternating current in a coil, a plurality of outgoing cables, and means for distributing said current to said cables in a predetermined sequence oomprising a circuit breaker in series with each of said cables, means connecting all or said circuit breakers to said coil and means including rotatable cam means for normally holding said circuit breakers in open position and closing the same in said predetermined sequence, some oi said circuit breakers being aligned on one side of the cam means in a line parallel to the axis of rotation of said cam means and the remainder said circuit breakers being similarly disposed on the other side oi said cam means.

6. In a magneto having means including a coil for generating low-tension alternating current, a plurality of circuit breakers, an outgoing cable connected to a terminal of each of said circuit breakers, means connecting the other terminal of each of said circuit breakers to said coil, and rotatable cam means for controlling the actuation or said circuit breakers, whereby the latter are opened and closed in a predetermined sequence and in timed relation with the cycles or current flowing in said coil, groups of said circuit breakers being disposed on opposite sides of said cam means and the circuit breakers of each of said groups being aligned in parallel relation to the axis of rotation oi said cam means.

7. In an ignition system for internal combustion engines, a magneto-generator comprising a coil and means for inducing low-tension alternating current therein, a plurality of transformer coils having the primary windings thereof in parallel circuits, a circuit breaker connected in series with each or said primary windings, means for normally uninterruptedly connecting one terminal of said first-named coil to each of said circuit breakers, means connecting the second ary winding oi each of said transformer coils to an ignition device in the engine, and cam means i'or actuating said circuit breakers whereby the same are opened and closed in predetermined sequence and in timed relation to one another.

8. In apparatus of' the class described, a coil, means including a magnetic rotor for inducing low-tension alternating current in said coil, a plurality of ignition coils having the primary windings thereof connected in parallel with each other and the secondary windings thereof in circuit with an ignition device of an engine, a circuit breaker in series with each of said primary windings, means for normally and uninterruptedly connecting each oisaid-circuit breakers ,to

one terminal or said first-named coil, cam means for actuating said circuit breakers whereby the same are opened and closed in predetermined sequence during each revolution or said cam means, only one or said circuit breakers being in closed position at any time and a diilerent one oi said circuit breakers being closed during each one-halt cycle of the alternating current produced in said first-named coil, and means drivably connecting said rotor and said cam means whereby the same are rotated in synchronism with each other.

9. In apparatus of the class described, a casing, a coil therein, means including a rotor in said casing for inducing alternating low-tension current in said coil, a cam having a plurality oi axially spaced lobes thereon, means drivabiy connecting said rotor and cam, an element mounted on said casing for limited angular adjustment about the axis of rotation of said cam, a bus bar mounted on said element, means for electrically connecting said coil to said bus bar, a plurality of movable contact supporting arms mounted on and electrically connected to said bus bar, a cam follower adapted to engage each of said arms and yieldingly engage said cam, a plurality of stationary contacts mounted on said element, each adapted to be engaged by a contact on one of said movable contact arms to form a plurality of circuit breakers, said cam being adapted to open and close said circuit breakers in predetermined sequence during each revolution or the cam and in timed relation to the current cycles in said first-named coil, a plurality of ignition coils, means connecting each of said stationary contacts to the primary winding of one of said ignition coils, means connecting the secondary winding of each of said ignition coils to a spark plug, and means connecting the other terminals of said spark plug and said windings to ground.

10. A magneto generator comprising a casing, a magnetic rotor rotatably mounted in said casing, a stator comprising a coil operatively assoelated-with said rotor, an angularly adjustable support mounted on said casing, a bus bar on said support, means electrically connecting said bus bar to said coil, a plurality oi circuit breakers mounted on said support, on contact of each or said circuit breakers being electrically connected to said bus bar and the other contact of each of said circuit breakers being connected to an outgoing conductor, cam means rotatably mounted in said support for actuating said circuit breakers in predetermined sequence, the axis of rotation of said cam means being coincident with the axis about which said support is angularly adjustable, and means operatively connecting said cam and said rotor.

11. A magneto generator comprising a casing, a coil in said casing, means including a rotor for inducing alternating current in said coil, a support mounted on said casing for angular adjustment relative thereto, a bus bar mounted on and insulated from said support, means eletrically connecting said bus bar to said coil, a plurality of circuit breakers on said support, one contact of each of said circuit breakers being electrically connected to said bus bar and the other contact of each of said circuit breakers being connected to an outgoing conductor, a plurality of condensers mounted on said support, means connecting each of said condensers in parallel with a different one of said circuit breakers, cam means rotatably mounted on said support for actuating said circuit breakers in predetermined sequence, the axis of rotation of said cam being coincident with the axis about which said support is angularly adjustable, and means operatively connecting said cam and said rotor.

12. A magneto generator comprising a casing, a coil in said casing, means including a magnetic rotor rotatably mounted in said casing for inducing alternating current in said coil, said casing having a circular opening in one side thereof, a support having a portion thereof piloted in said opening, means for securing said support to said casing for angular adjustment about the center of said opening, a bus-bar mounted on said support, means electrically connecting said bus bar to said coil, a plurality of circuit breakers carried by said support, one contact of each of said circuit breakers being electrically connected to said bus bar and the other contact of each of said circuit breakers being connected to an outgoing conductor, cam means rotatably mounted on said support for actuating said circuit breakers in predetermined sequence, the axis of rotation of said cam being coincident with the center of said opening, and means operativeiy connecting said cam and rotor for simultaneous rotation.

13. A magneto generator comprising a casing, a coil in said casing, means including a rotor for inducing alternating current in said coil, a rotatable cam having axially spaced lobes, groups of axially spaced circuit breakers on opposite sides of said cam, means connecting one contact of each of said circuit breakers to said coil, an outgoing conductor connected to the other contact of each of said circuit breakers, and means interposed between said circuit breakers and cam whereby the latter is operative to eifect the closing and opening of said circuit breakers in a predetermined sequence during each revolution of the cam.

14. A magneto generator comprising a casing, a coil in said casing, means including a rotor for inducing alternating current in said coil, a rotatable cam having axially spaced lobes, supporting means mounted for annular adjustment relative to said cam, two groups of circuit breakers mounted on said supporting means on opposite sides of said cam, said circuit breakers including means engageable by said cam whereby the latter is operative to close and open said circuit breakers in a predetermined sequence during each revolution of the cam, means connecting one contact of each of said circuit breakers to said coil, and an outgoing conductor connected to the other contact of each of said circuit breakers.

WALTER J. SPENGLER.

JAKOB R. FREI. GLEN H. DINGMAN.

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