US2552610A - Ignition apparatus - Google Patents

Description

May 15, 1951 R. E. WHITE Y 2,552,610

IGNITION APPARATUS Original Filed March 7, 1947 5 Sheets-Sheet l Fin! - INVENTOR.

ATTRNEY.

May 15, 1951 R. E. WHITE IGNITION APPARATUS Original Filed March 7, 1947 3 Sheets-Sheet 2 F1104 Y Z INVENTOR.

ATT

ORNEY.

May 15, 1951 R. E. WHITE 2,552,610

IGNITION APPARATUS Original Filed March 7, 1947 s Sheets-Sheet s ATTORNEY.

Patented May 15, 1951 IGNITION APPARATUS Raymond Edgar White, Sidney, N. Y., assignor to Bendix Aviation Corporation, New York, N. Y., a corporation of Delaware Original application March 7-, 1947, Serial No.

733,233. Divided and this application December 29, 1948, Serial No. 67,791

3 Claims.

This invention relates to electrical apparatus and more particularly to current generating and distributing devices adapted for use in ignition systems of internal combustion engines or the like and is a division of my co-pending application Serial No. 733,233 filed March 7, 1947.

One of the objects of the present invention is to provide novel apparatus of the above type which is specially adapted for but not limited to use in a high frequency condenser discharge ignition system.

Another object of the invention is to provide novel apparatus for generating electrical energy in a manner readily adapted for use in ignition systems of modern aircraft engines having large numbers of cylinders.

Still another object is to provide novel apparatus for distributing electrical energy in a predetermined manner to a plurality of loads of points of use.

A further object is to provide novel current distributing means which is so constructed as to be compact without introducing danger of flashovers and pre-ignition.

A still further object is to provide novel means in an ignition unit of the above type wherein the electrical wiring is simplified and wherein electronic units are novelly mounted for mechanical support and electrical connection.

Another object is to provide a novelly constructed magnetogenerator wherein a permanent magnet is so installed as to facilitate recharging thereof.

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 definition 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 vertical sectional view with parts broken away illustrating one form of current generating and distributing apparatus embodying the present invention;

Fig. 2 is a diagrammatic illustration of the magnetic circuit of the current generating means of Fig. 1;

Fig. 3 is a front elevation of a casting which may be employed in the construction of the distributor block;

Fig. 4 is a sectional view taken substantially on line G- l of Fig. 3;

Fig. 5 is a front elevation illustrating the completed distributor block and showing the relative positions of the brushes of the distributor rotor;

Fig. 6 is a sectional view taken substantially on line 6-6 of Fig. 5, and showing the distributor rotor in dotted lines;

Fig. 7 is an elevation view, on a reduced scale, of a mounting and wiring plate with the cover removed;

Fig. 8 is a diagrammatic view looking from the right in Fig. 1 and schematically indicating the electrical circuit; and

Fig. 9 is a detail View, partly in section, illustrating the mounting and electrical connections for an electronic tube.

One embodiment of the invention is illustrated in the drawings, by way of example, in the form of a unit comprising a relatively low voltage magnetogenerator, an ignition distributor and timing control elements electrically and mechanically associated with each other in a novel manner, said control elements comprising electronic means novelly mounted in the unit. The supporting structure of said unit includes a frame member ID (partly broken away) adapted to be secured to an engine casing, or the like, in an known manner, and a member ll, the two members being secured together by a plurality of stud bolts 12. A shaft I3 is rotatably supported by bearings M and I5 in the frame members and is adapted to be rotatably driven by the engine through a splined sleeve Hi.

The novel magnetogenerator comprehended by the inventions is adapted, in spite of its small size, to generate a relatively large number of current alternations or surges during each revolution of shaft [3. The particular structure illustrated produces 14 flux reversals through the coil per revolution of the shaft, and, when the latter is driven at one-half engine speed, sufiicient current impulses are generated to supply ignition for a 14 cylinder four cycle engine. The flux divider or rotor l'l comprises two laminated sleeves or rings is and I9 axially spaced on shaft I3 by non-magnetic means and suitably secured against axial and angular movement relative to the shaft. The periphery of each of said flux conducting rings is formed to provide seven radial projections or poles (Fig. 2) and the poles of one ring alternate circumferentially with the poles of the other. A larger or smaller number of such projections may be provided, depending -28 is opposite a projection on sleeve IE rotation of the rotor through one-fourteenth of 3 on the particular use to which the unit is to be put.

Below rotor I! there is mounted in frame member a pair of stationary, preferably laminated, pole shoes 22 and 23, the upper concave surfaces of which are in fiux conducting proximity to and have the same curvature as the outer surfaces of rings it and [9, respectively. A bar magnet 2:1 i mounted between the free ends of stator pole shoes 22 and 23 so that one shoe contacts the north pole of the magnet and the other shoe contacts the south pole. With the magnet mounted in this novel manner a coil of wire may be wound around it for the purpose of remagnetizing the same or remagnetizing may be effected by contacting the . poles 22, 23 with the poles of another magnet.

Mounted above the rotor ii is a transformer coil 25 having a primary winding P and secondary windings 89 (Fig. 8) wound on a laminated core 26 which is secured to frame member H] by studs 2'! with the ends thereof in magnetic contact with the upper ends of a pair of pole shoes 23 and 29.

When the rotor is in a position such that pole 23 is adjacent a projection on sleeve [8, the pole Upon a revolution from that position, pole shoe 23 will cooperate with ring it and pole 29 will cooperate with ring [8. Thus, with the rotor in any one of seven equally spaced positions, the magnetic lines or" flux flow from the north pole of magnet 24 through stator pole 23, rotor sleeve 19, pole shoe 2.; and back to the south pole of the magnet through core 25, pole shoe 28, rotor sleeve l8 and stator pole 22. With the rotor in any of seven other or intermediate positions, the lines of magnetic flux flow in the opposite direction through the coil, that is, from the north pole of the magnet through stator pole 23, sleeve I9, pole shoe 28, core 2%, pole shoe 2s, rotor sleeve i8 and stator shoe 22. Pole shoes 2t and 29 are preferably divided into two or more branches adjacent the rotor in order to cooperate with more than one projection on each of the flux conducting sleeves H3 and 19. However, one shoe on each of these poles may be sufficient. If desired, the second set of said pole shoes may be connected with the core of another coil and thus provide a dual magneto.

In a manner well understood in the art, the magnetic lines of flux, thus caused to flow through coil 25, eifect the flow of electrical current in the primary winding P of the coil. The circuit which includes said primary winding comprises a circuit breaker 30 (Fig. 8) operated by a rotatable cam 3| for periodically opening said circuit in accordance with known practices. The opening of the primary circuit at opportune moments causes a sudden collapse of the magnetic field around coil 25 and hence the induction of cur-- rent flow at a higher voltage in a secondary winding of the coil which is connected in an ignition circuit in a manner to be more fully hereinafter described.

Novel current distributing means are provided in combination with the above described energy generating means for distributing the electrical energy induced in the secondary winding of coil 25 to spark plugs in a plurality of engine cylinders, said distributing means being novelly so constructed and connected with the source of energy that a large number of spark plugs firing in rapid succession may be supplied through a relatively small distributor Without material danger of undesirable flashovers which tend to occur particularly at high altitudes and cause preignition in the cylinders. In the form shown, the distributor means comprises a stationary insulating block 32 surrounding shaft 13 and a finger or rotor 33 of insulating material mounted on shaft it for rotation therewith.

The construction of distributor block 32 is best illustrated in Figs. 5 and 6 as comprising a molded insulating block 34 having three concentric rings of arcuate contacts 35, 3B and 32 projecting from one face thereof. The total number of contacts in the two inner rings (M are shown but more or less may be provided) represents the number of spark plugs or other such loads served by the distributor, and each of these contacts 35 and 36 'is provided With a terminal boss 33 and 39, re-

spectively, which extends through block 34 for connection with an outgoing cable 46. In the present embodiment, the outer ring consists of seven live segments 2'! which alternate with seven longer segments H which are not in any electrical circuit but serve to mechanically bridge the live segments. Contact segments 3? are all electrically connected together by a wire ring 62 or the like, which is embedded in block 3 and has electrical contact with projections 43 on segments El. At least one of the latter has a terminal boss 44 (Fig. 3) by which ring 42 may be connected to the source of energy.

In the construction of the distributor block, a metal casting illustrated in Figs. 3 and a is first prepared and the ring :2 is placed thereon. The casting comprises a fiat disc-like annular portion 65 with the terminal bosses 38, 39, t4 and projections 43 extending in an axial direction therefrom. The disc is radially slotted. at equal intervals, such as at 3%, and has projections 47 thereon which serve to anchor segments ll in the insulating block of the finished structure. The insulating material 3:? is molded around the casting of Fig. 3 and the projecting face or disc portion 35 thereof is then out along the circular grooves t to form three rings which are in turn out along seven equally spaced radial grooves R9 to form the segments heretofore described. A sturdy and reliable structure embodying a large number or" parts is thus simply and inexpensively constructed. Block 32 may be mounted in frame member H by means of a plurality of studs which engage internally threaded inserts in the block.

The distributor rotor 33 comprises a block of insulating material molded around a sleeve 5i which is in turn keyed to shaft it. A pair of carbon brushes 52, slidably extend through passages in one end of rotor 33, the form-er being adapted to engage the outer ring of segments 3?, 4|, and the latter being adapted to engage the inner ring of segments 35. The free ends of said brushes have small coil springs secured thereto and connected by a stifi conducting bridge the center portion of which is connected to an extension spring 58 that is in turn suitably anchored in rotor 33. Thus, the brushes are resiliently held in engagement with their respective contact segments. A second pair, of similarly mounted brushes 5'! and 58 (the latter being shown diagrammatically only in Figs. 5 and 6) at the other end of rotor 33 serve to connect the outer ring of contact segments 31 with the middle ring of segments 36.

The pairs of brushes 52, 53 and 51, 58 are so arranged as best seen from the dotted line positions indicated in Fig. 5, that whenever current flows to input terminal 44 only one of the two outermost brushes 52 and 57 is in contact with a live segment 3?, the other being at that time in contact with a dead or disconnected segment A l. Current is thus supplied alternately through the two sets of brushes, and hence, alternately to the contacts in the two inner rings of segments and 36. Preferably, only one of the two brushes 52 and ET is in contact with a segment 3? at any given instant.

Novel means are also provided in combination with the above structure for simplifying the electrical wiring and mounting of the elements incorporated in the ignition system of which the magneto-distributor means described above are part. As illustrated, said means include a panel of insulating material secured in position on the frame iii, H by any suitable means such as bolts l2. Said panel 69 comprises a base plate 6i (Fig. 7) and a cover 62 (Fig. l) cemented thereon, the plate having recesses and grooves in the covered face thereof for receiving a plurality of contact elements 83 and connecting wires therefor, as best seen in Fig. 7, Panel G3 has a large opening E i cut in the center thereof and the circuit breaker til and a contactor or circuit maker 65 are conveniently mounted on frame member H in said opening for operation by the fourteen lobe cam 3| which is mounted on the free end of shaft 13.

Mounted in a novel manner on the back of the upper left corner of panel til, as. viewed in 8, is a full wave rectifier 6% which has its input terminals El and 63 connected to opposite ends of the secondary winding es of coil 25, said winding being center tapped to ground at it. The alternating current generated in secondary winding 82 is thus converted into a unidirectional current at the output or plate terminal ll of the rectifier. The latter preferably comprises a hollow metallic envelope l2 which the operative elements are mounted. Suitable leads, such as lead "it, from said element extend through a seal in the bottom of the envelope in accordance with known practice.

In order to simplify the electrical connections to the rectifier tube 66 and to provide a suitable mounting therefore, said tube is secured to a re-- cessed block i l of insulating material by means of an internally flanged sleeve that engages the shoulder it on said block and a flange ill on the tube. A wavy spring washer "i8 is preferably interposed between flange '5? and block '54. Molded into the closed end of the block is a terminal insert 79 for each electrical connection to the tube. Each of said inserts has an opening in which a lead or terminal wire, such as it, is soldered or otherwise suitably secured, and a threaded opening for receiving a combined terminal and mounting stud 57. The studs 67 extend through panel 56 and serve as electrical terminals, as well as mechanical means for securing the tube and its mounting on panel til. When a connection internally of the panel is to be made, terminal stud 61 is electrically connected with an element 63 through a lock washer Bil. If, an external connection is to be made, the end of the external cable is merely connected with the head of stud 67 or other similar stud in any well "known manner, "such as in the manner illus receiving the condenser casing. The terminal of the condenser extends through an opening 86 in panel to into which extends the tongue of an element (33 mounted in the panel.

The output terminal 3 i of the rectifier is also connected through an internal lead 87 to the anode terminal it of a gaseous discharge tube or electronic valve 8?? which may be mounted on panel 63 in the same manner as the rectifier. The grid terminal in; of the discharge tube is connected by an external lead 9! to one contact II I of contactor 55 and by an internal lead 92 to a terminal 93 of a special unit 9% which may be conveniently called RCL unit. The latter includes a grid stabilizing resistor 95 between terminals 93 and a grid charging resistor all and a grid condenser es in series between terminals 96 and 99, a grid current limiting resi tor lilfi in series with resistor 9? between terminals 933 and NH, and a reactance coil Hi2 between terminals 96 and ltii, the latter terminals being externally connected to ground through a conducting strip I04- and a mounting bolt l2. Terminal 99 is connected by internal leads 32 and N35 to the output terminal of the rectifier and terminal Nil is connected by an external lead N36 to the other contactof contactor st. The remaining terminal 5st of unit is internally connected by lead I01 to the cathode terminal Hit of the electronic valve 855 which latter terminal is in turn connected by an external lead it?) to the input contact segments, 3? of the distributor heretofore described.

The circuit breaker 3t may be constructed in.

accordance with the disclosure of Shoemaker et al., Patent No. 1,866,492. When the spring mountedioilower llii rides up on a lobe of cam.

constructed, except that the fixed contact is replaced by a spring mounted contact ill, the outward (downward, as viewed in Fig. 8) movement. of which is limited by a stop i it and the inward.

(upward) movement is yieldably resisted by a spring lit. Thus, when the spring mounted fol-- lower I id is on a lobe of the cam, the contacts are separated. As the foliower rides down into a valley of the cam, the contacts engage thereby closing the circuit and causing the spring or flexible arm on which contact 5 l i is mounted to move away from stop i it. Since the contacts are then free to move as a unit, any danger of one bouncing relative to the other at high operating speeds is virtually eliminated.

In operation, each time the points or contacts of circuit breaker 39 are operated by cam 3| which is driven at one-half engine speed with shaft [3, a surge of current is induced in one of the secondary windings 69 and passes through rectifier 66 to uni-directionally charge condensers 83 and 98, the flow of current to the latter being restricted by resistor 91. At this time the electronicvalve 89 is non-conductive. Thereafter, when it is desired to fire one of the spark plugs I I5, the

cam permits the points or contacts of contactor 65 to close thereby permitting condenser 98 to discharge through the grid circuit of the electronic valve 89 and thereby render the latter conductive to the charge on storage condenser 83. The latter accordingly discharges across the anode and cathode of tube 89 through the distributor in the manner heretofore fully described and thence through the primary winding H6 of a transformer coil, the secondary winding H1 of which is connected in series with the spark plug H5. The reactance coil IE2 is provided for preventing damage to discharge tube 89 in the event of a short in the output circuit thereof.

There isthus provided a novelly constructed, compact unit for generating and distributing high frequency current impulses at timed intervals to a plurality of spark plugs in the cylinders of an internal combustion engine. Said unit is a novel combination embodying novel generating means, novel current distributing means and novel simplified means for mounting and connecting the more or less fragile electronic tubes and other elements which may form a part of a high frequency ignition system.

Although only a single embodiment of the invention has been illustrated and described in detail in the drawings and the foregoing specification, it is to be expressly understood that the invention is not limited thereto. For example, if it is desired to do so, the contactor 65 may be placed in circuit between the storage condenser 83 and the input terminal M of the distributor, thereby eliminating discharge tube 89 and the RCL unit ea. Cther types of rectifiers, such as selenium rectifiers may be used. Various other changes could also be made, particularly in the specific construction, design, and arrangement of parts illustrated, without departing from the spirit and scope of the invention, as will now be readily apparent to those skilled in the art. For a definition of the limits of the invention, reference i had primarily to the appended claims.

What I claim is:

1. In a magnetogenerator, a rotor comprising two axially spaced annular flux conducting members each having equal number of radially extending projections equally spaced about the periphery thereof and the projections of one member being arranged alternately with the projections of the other member, a stator pole shoe arranged in flux conducting relation with each of said members, a magnet disposed between and in contact with said pole shoes and such that the lines of magnetic flux flow through the magnet in a direction longitudinally of the axis of rotation of said members, two pole shoes each bridging the space be seen and being associated with both of said members in flux conducting relation, said last named pole shoes being arranged to alternately cooperate with said members and in a manner such that when one is in flux conducting relation with one member during rotation of the rotor, the other is in flux conducting relation with the other member, and a coil inductively associated with said last named pole shoes.

2. In a magnetogenerator, a rotor comprising two axially spaced annular flux conducting members each having an equal number of radially extending projections equally spaced about the periphery thereof and the projections of one member being angularly displaced with respect to and arranged alternately with the projections of the other member, a stator pole shoe arranged in flux conducting relation with each of said members, a permanent magnet disposed between and in contact with said pole shoes and such that the lines of magnetic flux flow through the magnet in a direction longitudinally of the axis of rotation of said members, two pole shoes each of which bridges the axial space between and is associated with both of said members in flux conducting relation, said last named pole shoes being arranged to alternately cooperate with said members and in a manner such that when one is in flux conducting relation with one member during rotation of the rotor, the other is in flux conducting relation with the other member, each of said last named pole shoes having portions adapted to cooperate simultaneously with at least two projections on each said member, and a coil inductively associated with said last named pole shoes.

3. A magnetogenerator comprising a rotatably mounted flux divider consisting of axially spaced flux conducting rings, each of said rings having an equal number of equally spaced radially extending projections and the projections of one ring alternating circumierentially with the projections of the other ring, a stationary bar magnet, a pole shoe extending from one end of said magnet into permanent flux conducting relation with one of said rings, a pole shoe extending from the other end of said magnet into permanent flux conducting relation with the other of said rings, a coil having a core, pole shoes extending from opposite ends of said core into flux conducting relation with said rings, the free ends of said last named pole shoes being arranged so that each of said shoes bridges the axial space between said rings and alternately cooperates with each of said rings as the latter rotate and so that when one of said last-named pole shoes is in flux conducting relation with one of said rings the other of said last-named pole shoes is in flux conducting relation with the other of said rings.

RAYMOND EDGAR WHITE.

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

UNITED STATES PATENTS Number Name Date 926,225 Williams June 29, 1909 1,853,220 Nowosielski Apr. 12, 1932 2,422,151 Upton June 10, 1947 FOREIGN PATENTS Number Country Date 214,682 Great Britain Apr. 22, 1924

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