US1584881A - Engine ignition timer - Google Patents

Description

May 18,1926. 1,584,881

' M. MALLORY ENGINE IGNITION TIMER Filed June 17 1925 2 Sheets-Sheet 1 Hq El Zlwuwntoz c/bla/u'on dbidm May 18 1926.

M. MALLORY ENGINE IGNITION TIMER Filed June 17 1925 2 Sheets-Sheet 2 gwuanfo'a Patented May 18, 1926.

UNITED STATES PATENT OFFICE.

MARION HALLORY, 0F TOLEDO, OH IO, ASSIGItIOR TO MALLORY ELECTRIC CORPORA- TION, OF TOLEDO, OHIO, A CORPORATION OF OHIO.

ENGINE IGNITION TIMER.

. Application filed June 17, 1925. Serial No. 37,881.

My invention has for its object to provide an ignition timer or circuit breaker for usev in connection with ignition systems of ditferent kinds to produce, from a small primaryeurrent, substantially uniform high tension sparks at theelectrodes of the spark plugs of internal combustion engines, notwithstanding variations in the speeds of the engines.

As is well known in the art of engine ignition, the induction coils have characteristic time constants due to their characteristic self induction that limits the quantity or strength of the primary current that will be permitted to pass through the primary circuit before'lthe expiration of the given time that is characteristic of the coil. As the current builds up in the coil when the circuit is first closed, the counter electromotive force retards its rise and, consequently it does not rise to its full value, as determined by the ohmic law of its circuit, for a comparatively long period after the circuitis closed. If the controlling or spark producing circuit breaker opens the circuit before the primary current is fully built up in the primary coil, there is a correspondingly magnified or multiplied reduction of the secondary current which results in a corre-: sponding magnified reduction in the heat or ignition value of the sparks produced in the electrodes of the spark plugs. It also results in an early cessation of the sparks altogether,

and the engine cylinders fail to fire. lVhen, therefore, the engine, and consequently the timers, are speeded up, the periods of closing the circuit is reduced to within the. time constants which results in poor ignition or n'o-ignition at high speeds. The coils, how-v ever, may be designed to produce short or 'low:time constants, but this naturally results in an enormous battery loss since, probably, the greater portion of the time, the engines will be operated at relatively low speeds. It is therefore, impossible to design induction coils to produce. the desired spark efiiciency and at the same time prevent the battery losses. In the use of engines having more than four cylinders, there is a corresponding increasein the number of times that the induction coil of the ignition system is required to produce the necessary high tension currents to cause the formation of the increased number of sparks and since the periods allowed for building the current to its full value in advance of each spark must necessarily come within the period of each cycle of the engine, it is absolutely requisite thatthere be no waste of the time, during the period of the cycle, inthe functioning of the parts of the ignition system. here eight and twelve cylinderengines are used, this economy of time is absolutely lmperative, and because of the ditficulties that have arisenin connection with the ordinary lgnition systems it has been suggested that a duplicate set of ignition apparatus be used in order that the cylinders may be fired at high speed and prevent battery losses during the periods when the engines are operated at low speed. This invariably results in two different conditions of firing in the engine, one that is caused by the difierent self inductions that are produced by the two ignition coils, and the other due to a difference in timing or want of synchronism, as between the timing elements. The effect on the engine is that one set of cylinders fire in advance of the other set in each cyclic period of the engine.

y my invention the period of the cycle of the engine is taken up quite entirely by the elements of the ignition system in the performance of their required functions to alternately build the magnetic flux in the induction coil to the maximum, and to enable the pioduction of the high tension current and, consequently sparks of high heat value atthe spark electrodes of the engine, particularly, at the maximum speed of the engine, and at the same time prevent battery losses, particularly, during-the periods'when the engine is running at lower speeds. Thus my invention provides a means for maintaining substantially constant periods in which the primary circuit is closed notwithstanding the speed of the engine, the said periods being preferably as long or slightly longer than the time constant of each induction coil used in the particular ignition system. The invention may be used in connection with ignition systems of different forms and conjointly with induction coils of difierent vforms and in circuits having different self inductance. To illustrate a practical application of the invention, I have shown a system and a timer used in connection as for advancing the periods of time of each circuit closure in the cycle of operations of the engine, in order that thetimes of the firing of the cylinders of the engine may take place at the proper times to produce the maximum power at the speed at which it is run. The system selected as-an example is shown in the accompanying drawings and is described hereinafter.

Figure 1 of the drawings is a vertical section of the timer that is used in the preferred form of my invention. Fig. 2 is a view of a cam for controlling the operation of a circuit closer. l ig. 3 illustrates the second cam for controlling another circuit closer. Fig. 1 illustrates an edge view of either of the cams shown in Fig. 2 or Fig. 3. Fig. 5 is a view of a section taken on the plane of the line 55 indicated in Fig. 1, the cover of the device being shown removed. Fig. (3 illustrates a pair of cams for operating the circuit closers. Fig. 7 is a view of a section taken on the plane of the line 7+7 indicated in Fig. 1. Fig. 8 is a view of a section taken through a plane at right angles to the plane of the section shown in Fig. 7. Fig. 9 is a diagrammatic illustration of the connections of the parts embodying my invention. Fig. is also a diagrammatic illustration to indicate the constancy of the periods during which the primary circuit of the ignition system is closed, notwithstanding the speed of the engine.

The timer is suitably mounted in the chassis of the automobile, such as, by means of the plate 1. It is driven by the shaft 2 that may be connected to the crank shaft of the engine to produce rotations at the usual ratio of speed in order to cause the cylinders to fire at the proper times in the cycles of operation of the engine. The shaft 2 extends through protruding bosses 3 and 1 located on the outside and on the inside of the shell 5. The shaft 2 is connected to a hub 6 having fingers 7. Pivot rods 8 extend laterally from the fingers 7 and support a metal ring 9 of considerable weight. The ends of the rods 8 that pivotally support the ring 9 are connectedby means of spiral springs 10 to the ring 9. The springs 10 are located in recesses 11 formed in the sides of the ring. The springs 10 tilt the ring 9 relative to the axis of the shaft 2. Rotation of the shaft 2 and of the ring 9 causes the ring 9 to seek a plane sub stantially at right angles to the axis of the shaft 2 against the yielding resistance of the springs 10. Thus the ring 9 oscillates about the axes of. the rods 8 according to the speed of theshaft 2 in the manner well known in the art-{Curved plates 15 and 16 are connected to :opposite sides of the ring 9 and extend in a direction away from the axis of the shaft 2, that is, the plates tiall at ri ht an les to the axes of the bearing rods 8 and the plate 15 extends downward while the plate 16 extends upward, the springs 10 being so connected to the ring 9 and the ends of the rods 8 as to cause that portion of the ring 9 to which the plate 15 is connected to be normally raised towards the axis of the shaft and the portion of the ring 9 to which the plate 16 is connected to be normally lowered towards the axis of the shaft. The plates 15 and 16 are provided with slots that are located at desired angles with respect to the plane of the axis of the shaft 2 that passes through the vertical central line of the plates 15 and 16.

The slots 17 and 18 of the plates 15 and 1G operate upon pins 19 and 20 that extend through the slots to cause the rotation of cams that operate the circuit closers of the ignition system. The pin 19 is connected to a shaft 21 while the pin 20 is connected to the sleeve 22. The cam 23 is connected to the shaft 21 and the cam 24 is connected to the sleeve 22. Thus the rotation of the shaft 21 is communicated to the shaft 21 and the sleeve 22 through the ring 9, and

the plates 15 and 16. The relation, however, v

between the shaft 2 on the one hand and the shaft 21 and sleeve 22 on the other is shifted according to the speed of the shaft 2 by movement of the ring 9 against the resiliency of the springs 19, since the pins 19 and 20, connected respectively to the shaft 21 and the sleeve 22, are shifted angularly by reason of the angular relation of the slots 17 and 18. Thus the cams 23 and 2% that operate the circuit closers of the ignition system may be advanced relative to the direction of rotation of the shaft 2 according to the speed of the shaft. Tn the construction shown in the drawing a pair of circuit closers are connected in branches of the primary circuit and the earns 23 and 2 1 have as many protruding portions or cam points as there are cylinders in the engine that operate to open the branch circuit through the circuit breaker with which it is associated, and consequently when one or the other of the circuit breakers is closed the primary circuit through the induction coil will be closed but the circuit will not be opened to produce the spark in the secondary circuit until both of the circuit closers are opened by their associated cams. Thus by reason of the difference in the angles of the slots 17 and 18 to the plane of the axis of the shaft 2 that extends through the center lines of thelates 15 and 16, the period of closure of t e primary circuit may be maintained constant or maintained sufltlt) movable contacts 34.

ficiently long to permit the current of the primary circuit to rise to approximate maximum notwithstanding the self induction or counter electromotive force of the coil. Thus, relative to the axis of rotation of the cams 23 and 24:, the opening periods increase, but owing to the increased speed of the cams the period of closure of the primary circuit will approach constancy notwithstanding the changes of the speed of the engine, or may be maintained substantially the same as the time constant of the particular induction coil in connection with which the timer may be used.

The shaft 21 and the sleeve 22 are maintained in rotative position by means of the ball bearing 29 that forms a part of the enclosing case. The circuit breakers 30 and 31 are supported on a plate 32, the parts of the circuit breakers being properly insulated in order that the breakers may perform their functions. The breakers30 and 31 are of the type well known in the art that are commonly used for breaking the primary circuits by the operation of the cams. They are provided with the fixed contacts 33, and the The movable contacts are connected preferably through the springs in the primary circuit in the manner illustrated in the diagram shown in Fig. 9. As is usual the circuit breaker contacts are shunted by means of a condenser 36 which may also be mounted on the plate 32. These parts are readily connected in the primary circuit by means of the wires 37 and 38 located in the shell 2) and the binding post 39 that forms a ready means for connecting the parts within the shell :29 with the wireexternal thereto. and which forms a part of the primary circuit. The distributor may be connected to theupper end of the shaft 21 and to the cam 23. As shown in Fig. 1 the arm 40 operates to cause the secondary circuit to be completed through the spark plugs of the cylinders of the engine in succession in the manner well known in the art. The distributor is mounted in the upper end of the shelletl which is removably secured by means of the elastic hooks 4:2. that commonly used and forms no part of my invention. The connections through the timer are diagrammatically illustrated in Fig; 9 of the drawings.

The operation of systems containing my invention is best described by reference to Figs. 9 and 10 of the drawings wherein the means for automatically maintaining the proper period of closure of the primary circuit to approximate uniform periodsof closure of the primary circuit notwithstanding the variations in the speed of the engine, is

-- indicated. The primary circuit comprises the battery 45. the primary coil 46 of the induction coil 47 and the branch circuits 48 This part of the structure is similar to.

in which the circuit closers 30 and 31 are located, the branch circuits are connected'to the battery 45. The secondary circuit consists of the secondary coil 49, the distributor 50 and the spark plugs51, the circuit being completed through the ground and the batterv.

The circuit breakers 30 and 31 being located in branch circuits the primary circuit will be completed through either branch when its circuit breaker is closed or through both branches when both branches are closed. The plates 15 and 16 that control the relative positions of the cams 23 and 24 thus affords a means for causing the overlap between the closing periods of the circuit breaker to vary according to the speed of the engine, that'is, to increase the overlap as the speed increases. This maintains ample opportunity for the primary current to build upin the primary coil 46 although the speed of the engine may be increased to its limit. This is indicated in Fig. 10. The positions 23' and 24 indicate the closed periods of the circuits breakers controlled by the cams 23 and 24 respectively. As the cams are shifted relative to each other their periods-of closure overlap so as by shifting both cams 23 and 24 by mean? of the governor ring 9 I claim:

1.' In an ignition timer, a pair of circu t breakers. a cam for operating each circuit breaker. means for causing one of the cams to advance opening times of the circuit breakers relativeto the other of the cams and according to the speed of the engine.

2; In an ignition timer, a pair of circuit breakers, a cam for operating each circuit breaker means for causing thq cams to advance according to the speed of the engine and to difl'erent extents, the latter variation being also according to the speed of the engine.

3. In an ignition system, a primary circuit having a battery and a primary coil. of an induction coil a plurality of circuit closers located in 'branch circuits, means for maintaining the circuit closed through one or more of the branch circuits during substantially constant periods notwithstanding the variations in the speed of the engine.

liIO

l'lil 4. In an ignition timer for internal com bustion engines, an electric circuit having a source of current, a plurality of circuit breakers connected in the said circuit, means for operating one of the circuit breakers to advance in its times of opening the circuit relative to the other circuit breaker upon increase of the speed of the engine.

5. In an ignition timer for internal combustion engines, a circuit having a source of current, a pair of circuit breakers located in parallel circuits connected to the said source, means for operating the said circuit breakers to advance the breaking of the circuit by the circuit breakers upon increase of the speed of the engine.

6. In an ignition timer for internal combustion engines, a circuit having a source of current, a pair of circuit breakers, means for operating the said circuit breakers to advance the breaking of the circuit upon increase of the speed of the engine, and to ad- Vance the times of breaking the circuit by one of the circuit breakers relative to the times of breaking of the circuit by the other circuit breaker upon increase of the speed of the engine.

7. In an ignition system for internal combustion engines, a primary circuit having a source of current and an induction coil and a plurality of circuit closers connected to the said primary circuit in parallel, means for operating the circuit closers to increase the closure period of the primary circuit as measured in degrees of rotation of the crank shaft of the engine on increase of the speed of the engine.

8. In an ignition system for internal combustion engines, a primary circuit having a is. weasel In an ignition system for internal combustion engines, a prin'iary circuit an induction coil ha ring a source of current and a pair of branch circuits, a circuit breaker located in. each oi the circuits, a cam for op-v erating each of the circuit breakers, an engine driven governor for operating the cams to increase the closure period as measured in degrees of rotation of the crank shaft of the engine on increase of the speed of the engine.

10. In an ignition system for internal combustion engines having a prin'iary circuit, a pair of cams, a pair of circuit breakers connected in parallel to each other and in series with the primary circuit, an automatic governor for controlling said cams to open the circuit breakers simultaneously at high engine speed and to open them at different intervals at low engine speed to increase the degrees of closure of the primary circuit.

ill. In an ignition system for internal combustion engines, a primary circuit, a pair of earns, a pair of circuit breakers connected to the primary circuit and automatic gov ernor connected to the said cams to advance both cams in'the same direction of rotation as the engine speed increases and "for advancing one can] to cause the ignition to occur earlier in the cylinders of the engine and advancinggrthe other cams'ill further in the direction of its rotation to increase the degrees of closure of the primary circuit. 12. In an ignition system for internal combustion engines, 'apoir of canes each having cam points, a circuit breaker operatcd by each of the cams, an automatic governor operated by the engine for controlling said cams to draw the cam points angularly together at low engine speed and draw the cam points apart at high engine speed to change the degree of closure at dil ferent engine speeds.

In testimony whereof I have hereunto signed my name to this specification.

MARION MALLORY.

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