US2173828A - Ignition system and apparatus - Google Patents

Description

p 1939- J. A. DORAN 7 2,173,828

IGNITION SYSTEM AND APPARATUS Original Filed Sept. 10, 1952 2 Sheets-Sheet 1 p 1939- I J. A DORAN 2,173,828

IGNITION SYSTEM AND APPARATUS Original Filed Sept. 10, 1952 2 Sheets-Sheet 2 Patented Sept. 26, 1939 UNITED STATES PATENT OFFICE Application September 10, 1932, Serial No. 632,483 Renewed December 3, 1937 Claims.

This invention relates to ignition systems, and particularly pertains to ignition systems used for internal combustion engines.

The conventional battery ignition systems have I many inherent disadvantages, due primarily to the construction and operation of their breaker contact points, ignition coils and spark plugs. Ordinary contact points usually have only a very small part of their surface in electrical contact, so that they burn and pit at one small point, and thus set up a. serious resistance against the passage of current, particularly at starting speeds and at high speeds. When stronger coils are employed to compensate for the losses at the breaker points, the contacts burn proportionately faster. The conventional ignition coils also have several disadvantages which weaken their power and shorten their life.

To overcome these troublesome defects in ignition systems, I provide an ignition system with such improvements in the construction and operation of the component parts, as will produce the maximum spark strength required, with minimum current consumption, with lessened resistance at the breaker contacts, with elimination of burning and pitting of the contacts, with greatly increased durability and life of coil, and with generally improved results in the operation and power output of the engine. To accomplish these improvements I have devised and arranged the various elements of my ignition system with many novel features.

Thus, I have utilized what I term a transmuter in the system, to provide a periodic reversal of current through the breaker contacts. Preferably, I use a lever oscillating-at half the speed of the breaker arm to make a contact on one side while the breaker arm is open, and to make a contact on the other side when the breaker arm next opens. The current supply is connected to two plates on the oscillating lever, one positive and the other negative; one pair of the receiving contacts is connected to the breaker arm and the other pair to the breaker screw, so that the breaker contacts have their polarity reversed at every opening.- -The reversal of current through the breaker contacts has important advantages, as hereinafter described.

With the above and other objects and advantageous features in view, the invention consists of a novel method of operation and assembly and a novel arrangement of parts more fully desclosed in the detailed description follawing, in conjunction with the accompanying drawings, and more particularly defined in the claims appended hereto.

In the drawings,

Fig. 1 is a diagrammatical view showing the general plan of the ignition circuit;

Fig. 2 is a view similar to Fig. 1 showing a mod ified arrangement;

Fig. 3 is a vertical section through the distributor head on the line 33 of Fig. 4;

Fig. 4 is'a plan view of the distributor head with the cap removed;

Fig. 5 is a perspective view of the transmuter arm;

Fig. 6 is a perspective view of the rear plate therefor;

Fig. 7 is a perspective view of the negative plate therefor;

Fig. 8 is a perspective view of one of the fixed contact frames;

Fif. 9 is a perspective view of the distributor operating shaft showing the breaker and transmuter cams.

Referring to the drawings, the general circuit employed in my novel ignition system-is diagrammatically shown in Fig. 1, and includes a line circuit In for supplying current to the primary of the ignition winding II, this circuit having a battery I 2 and the usual switch I3. A condenser II is connected across the line, and a transmuter I5 is arranged to periodically reverse the current supplied to a contact breaker i6 by alternately connecting points A to D and B to C, whereby the primary winding receives a periodically reversed current, instead of the usual direct current. The secondary winding is successively connected, through the distributor arm ll, with contacts I8 for conducting the high tension current to the spark plugs 19 and I9, which are in series relation in the secondary circuit. Fig. 2 shows an alternative circuit that reverses through the breaker points only, the parts beng similarly designated; this type of circuit may be preferable when the coil is located at a distance.

It has been determined that the usual interrupted direct current carries particles of metal from the negative contact face to the positive contact face of the breaker points, eventually eating holes in the negative contact point and building up, in irregular formation, the positive contact point. This transfer of metal occurs when the contacts are arcing while being opened; as a result, the contact surfaces become so irregular and carbonized that the contact is poor and the high resistance restricts current flow. With such reduced current, the spark is weakgrounded, plate ened and a high speed, high compression engine misses.

Clean contacts of large surface deliver the maximum current and operate an engine at much higher speed without skipping. At high speeds, the duration of contact is such an infinitesimal period of time that it is exceedingly important to provide the best possible contact surfaces. Furthermore, the breaking of corroded contacts is not sufficiently decisive to produce the desired powerful hot spark at each spark plug.

When the current at the breaker point is transmuted, and the polarity of the breaker contacts thus periodically reversed, there is no transfer of metal from one contact to the other, and there is no pitting or building up. Preferably, the current is reversed at every opening of the breaker contacts, although the transmuting mechanism may if desired be arranged so as to reverse less frequently, and may allow the breaker contacts to make several continuous openings with each polarity between each reversal of current. To avoid arcing at the transmuter switch, I design the actuating cams to open the breaker contacts While the transmuting switch is closed, and to reverse the transmuter switch while the breaker contacts remain open.

The transmuting mechanism may be mounted in any convenient location, but I prefer to mount the mechanism inthe distributor as shown in Fig. 3 in order to simplify the construction and the wiring connections. The distributor has the usual body 20 and cap 2|, the breaker and transmuter mechanism being mounted on the plate 22 which is preferably made of an insulation material such as fibre or Bakelite. The distributor shaft 23 extends vertically through the body and plate, and has the usual wiper 24 for distributing the high tension current to the terminal inserts 25 through the spring 26 from the central termi-- nal insert 21, which receives high tension current from the coil. Mounted on the shaft 23 are the breaker arm cam 28 and the transmuter cam 29; the breaker cam, as shown in Fig. 5, having lobes 30 corresponding in number to the engine cylinders, and the transmuter cam having lobes 3| numbering half the breaker cam lobes.

Referring now to Fig. 4, the breaker arm 32 is shown formed of a fare block 33-having a bumper projection 34 and a fulcrum bore 35 equipped with a metal, preferably brass, bushing 36 for mounting on the pivot pin 31 fastened to the distributor plate. A spring 38, preferably formed of a non-ferrous alloy of a high copper content, is riveted to the fibre block and its outer end under tension against a fixed post 38a. An extension 39 is also riveted to block 33, its outer end being provided with a contact 40 adapted to strike against the adjustable self-alining contact 4! mounted on the distributor plate. As shown, the bumper 34 is pressed against the lobes 3t, thus causing the breaker arm. to oscillate on movement of the breaker cam, and allow the contact 40 to strike contact 4!, closing and opening the circuit.

The transmuter mechanism includes a fibre bar 42 having a bumper projection 3 and a fulcrum bore 4 1 equipped with a metal bushing =15 for pivoted mounting onthe pivot pin 46 fastened to the distributor plate. On the side or" bar s2 is mounted a plate 49 and lever spring dl which is under tension against a fixed post 13, electrically connected to ground through strap 59 and screw *3 As battery usua ly has its negative terraimay he referred to as of positive polarity. The negative plate 52 and the lever spring 51 are mounted on the opposite side of 42. ,The outer end of spring 51 is under tension against a fixed post 58 electrically connected to strap 6| which serves as the terminal to receive the primary lead wire. The negative plate 52, spring 51, post 58, and strap 5| are all insulated from the distributor. The two outer ends 5| and of plate 49 serve to contact alternately against the spring contacts 53 and 54. The two outer ends 62 and 63 of plate 52 serve to contact alternately against the spring contacts and 56. The spring contacts 53 and 55 are mounted in the frame '64, which is adjustable by means of screws 65, and the spring contacts 54 and 55 are mounted in the frame 65, which is adjustable by means of screws 61, each frame being adjusted and secured so that the plate contacts strike the spring contacts properly at each end of their stroke.

Frame 64 is electrically connected by strap 68 to the post 3811, so that frame 64 supplies current to the breaker arm contact 40. Frame 66 is electrically connected by strap 69 to the adjustable bracket 10 which carries the self-alining contact 4|, so that frame 66 thus suppliescurrent to contact 4 I. It is obvious that when 62 contacts with 55, 50 contacts with 54, delivering positive current to the contact 4|, while negative current goes to contact 40; when 5| contacts with 53, and 63 wiih 55, positive current goes to 40 while negative current goes to 4|.

The operation of the transmuter mechanism may now be explained. As the distributor shaft revolves, the breaker arm bumper is pressed against the lobes 30, while the transmuter bumper is pressed against the lobes 3|. The location of the bumpers is such as to synchronize their movements. While the transmuter is'in contact, the breaker arm opens; while the breaker arm remains open, the transmuter bar moves across to the opposite contacts; while on such contact, the breaker arm opens; while the breaker arm remains open, the transmuter bar moves back to the opposite contacts, thus completing the cycle. The reference letters A and C in Fig. 4 correspond to the reference letters A and C of Fig. 1. The contacts B, B correspond to the reference letter B, and the contacts D, D correspond to the reference character D in Fig. 4.

As explained in Fig. l, the wiring connections may be such that the current is reversed through the primary of the coil. This is highly advantageous as it allows the coil to operate similarly to an alternating current transformer. Such alternating or reversing of current tends to hasten the demagnetizing of the core after each impulse, so that the coil operates with efliciency at higher engine speeds than is possible with a constant polarity.

However, if preferred, my ignition system may be wired as in Fig. 2, without changing the direction of current through the coil, to avoid excess wiring to a remotely located coil.

Instead of using an oscillating transmuter, it may be desirable or preferable, in certain construetions,.to use instead a of Bakelite or other insulating material, with rings thereon, carbon contacts being mount-ed on a Wiper arm and contacting the rings. Preferably, the disk is mounted in the distributor base above the breaker arm mechanism, and the carbon contacts are mounted on the lower face of the wiper. Or, copper segments may be mounted on a small revolving drum, with carbon brushes engaging the segments to receive the battery current and transmute it to reversed current.

The transmuting method prevents all pitting and burning of breaker contact surfaces. Inasmuch as one set of clean contacts with large bearing surfaces can transmit current fast enough for high speed engines, there is no need of supplying the conventional dual sets of breaker mechanisms. Therefore, with my transmuting mechanism, only one set or breaker points are required. As the transmuting mechanism costs no more than a breaker set, the complete distributor costs no more than the ordinary dual set distributor. Thus the transmuting method produces the above described advantages without any increase in manufacturing costs.

While I have described a specific ignition system, it is merely given by way of example to show one embodiment of the invention, and it is obvious that many changes in the general arrangement of the parts, in their specific form, in their size, and in their relative position, may be made without departing from the spirit and the scope of the invention as defined in the appended claims.

I claim:

1. In an ignition system the combination of an ignition coil, an interrupter, a source of current; a circuit including the primary of said coil, said interrupter and said source; switching means in said circuit operating each time said interrupter is open for alternately conditioning the circuit for reversal of current therethrough, whereby each closing of said interrupter will effeet a reversal of said current, and a spark plug system fed by energy from the secondary of said coil.

2. In an ignition system thencombination of an ignition coil, an interrupter, a source of current; a circuit including the primary 0! said coil, said interrupter and said source, a reversing switch in said circuit, means operating each time said interrupter is open for opening and reversing said switch, thereby reversing the direction in which current flows through said primary and said interrupter each time the interrupter closes, and a spark plug system fed by energy induced in the secondary of saidcoil.

3. In a current reversing system, an ignition coil including a primary winding, an interrupter, a reversing switch, a source of direct current; connections between said winding, said interrupter, said switch and said source whereby the polarity relation of said source to said winding and said interrupter may be alternately reversed, said switch and said interrupter operating in cycles each comprising a period during which said interrupter is open and said switch opens and reverses, and a period during which said switch remains in its reversed position and said interrupter closesand opens, and a secondary winding and a circuit connected thereto to deliver oscillating current to a spark plug system.

4. In an ignition system, a coil including a primary winding, an interrupter connected in series with said winding, a source of direct current, and switching means connected thereto for al-- ternately reversing the polarity of the contacts of said interrupter, said switching means operating each time said interrupter contacts are opened.

5. In an ignition system, an ignition coil including a primary winding; a circuit connected thereto including an interrupter, a reversing switch, and a source 01' current; an oscillatable bar forming the moving element in said reversing switch, a cam for said interrupter, a second cam for controlling the movement of said bar, a shaft forming a common support for said cams, said cams being so timed relative to each other that while said first cam is holding the interrupter open, said second cam shifts said bar to a reverse position, and while said first cam is closing and opening-said interrupter said second cam is maintaining said bar in said reverse position, a secondary winding in said coil, and a spark plug system fed by energy from said secondary winding.

JAMES A. DORAN.

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