US3018413A - Transistorized ignition system - Google Patents

Description

Jan. 23, 1962 N. T. NEAPOLITAKIS 3,018,413

TRANSISTORIZED IGNITION SYSTEM Filed Jan. 21,

FIG!

mmvrom NICHOLAS T NEAPQLITAKIS United States Patent 3,018,413 TRANSISTORIZED IGNITION SYSTEM Nicholas T. Neapolitakis, Chicago, 111., assignor to Shurhit Products, Inc., Waukegan, Iil., a corporation of Illinois Filed Jan. 21, 1960, Ser. No. 3,763 6 Claims. (Cl. 315-206) This invention relates in general to an ignition system for internal combustion engines for automobiles and the like, and for jet engines for aeroplanes.

Among the objects of the invention are, to utilize a push-pull oscillator for generating alternating current power; to prevent premature firing by controlling the voltage generated by the breaker set; reducing the current through and extending the life of the breaker set; to provide a transformer for controlling the voltage generated by the transistors and the feed back windings so that the high voltage at the output remains nearly constant at high speeds.

A further object of the invention is to provide a highly eificient ignition system capable of delivering extremely high voltages without any basic modification of the ignition installation, reducing the current through the breaker points to negligible values extending the life of the breakers by means of small inexpensive transistors, resistors and transformers.

Other objects of the invention will appear in the specifications and will be apparent from the accompanying drawings in which:

FIG. 1 is a wiring diagram of a transistorized ignition system for automobile engine op ration; and

FIG. 2 is a wiring diagram for a transistorizing ignition system for jet engines.

When the breaker points in a transistorized ignition system are open, the switching winding is ineffective and flux from primary winding links with feed back windings so that the oscillator becomes excited. The alternating flux so generated, interlinks with the secondary of the transformer which develops sufi'icient voltage to excite a standard ignition coil to a high voltage such as 21,000 volts and over. When the points are closed (with the switch and winding shorted), the switch and winding prevent the flux generated in primary windings from linking with the feed back windings and thus prevent the oscillator from operating.

Due to inherent intricacies in the operating principles of a transistorized push-pull oscillator system for generating alternating power, it may be preferable to start an ordinary automobile engine system with a standard coil alone and then to switch to the transistor push-pull system as herein provided.

Referring now more particularly to FIG. 1 of the drawings, a push-pull transistor system is described in connection with an ordinary standard automobile ignition coil 10 which is grounded at one end and connected to a spark plug distributing system at the other. To this ignition coil is connected a secondary winding 12 of a transformer 14 which has primary windings 16 and 18 connected to a common ground 20 between them and with the outer ends connected by conductors 22 and 24 to the collectors of transistors 26 and 28 respectively. The emitters of these transistors are connected together and through resistances 30 and 32 to a ground 34. The bases of the two transistors are connected by conductors 36 and 38 to opposite feed back windings 40 and 42, the other ends of which are connected by conductors 44 and 46 respectively to a point between the two resistances 30 and 32, thus forming a push-pull connection.

The push-pull system is activated from conductors 48 which connect the emitters of the transistors, and a conductor 50 is connected thereto and through a resistance 52 and a fuse 54 in series to a terminal 56 of a regular ignition switch represented as an On terminal. A conductor 62 connects the On terminal to a resistor 58 and through a conductor 60 to a terminal 64 of a toggle switch 66. The toggle switch has an arm 72 movable from an intermediate position to engage terminal 64 or a spaced terminal 70 which is connected through a conductor to a battery 76 and to ground.

The arm 72 of the toggle switch 66 is connected to the energizing coil 78 of the relay switch by a conductor 74. The contact 70 of the toggle switch is connected to a switch arm 71 of the ignition switch (or to the foot starter switch). Thus the toggle switch provides means for energizing the relay either momentarily through the starting provisions of the car by having the toggle switch arm 72 in engagement with the contact 70, or by energizing the relay continuously by having the switch arm 72 in engagement with the contact 64.

Since the position of the relay contacts determine whether the car is run on a transistorized or a standard ignition system, the toggle switch 66 provides means to run the car on standard ignition if it becomes necessary.

The relay switch having the winding 78 is represented as having an extending core 80 for engaging movable contact arms of switches A, B and C. When the relay winding 78 is energized, the contact arms of the switches are moved into engagement with corresponding contacts A1, B1 and C1 and when the winding is de-energized, the switch arms make engagements with the back contacts A2, B2 and C2 respectively. The movable arm of switch A is connected to a battery terminal 82 of the standard ignition coil 10, by a conductor 84; contact A1 is connected by conductor 86 to the normally low voltage side of the standard battery resistor 58. The movable arm of switch B is connected by a conductor 92 to the ignition breaker set 94; contact B1 is connected by a conductor 83 to the distributor terminal of the standard ignition coil 10; contact B2 is connected by a conductor 106 and a conductor also connected to contact C1 with one end of the switching winding 98. The movable arm of switch C is connected to ground; the contact C1 is connected by a conductor 100 to one end of the switching winding 98, the other end of which is grounded; and the contact C2 is connected by a conductor 108 with the distributor terminal 90 of the ignition coil.

From the above diagram, it will be seen that while the car (or its engine) is being started, the relay 78 is connected in the number 1 switch position which connects the ignition system in the standard starting manner. When the engine starts, the starter motor is disconnected from the battery, the relay winding is de-energized, and the contact arms of the switches A, B and C return to the number 2 position. The contact A2 of the switch A connects the battery terminal 82 of the standard ignition coil by conductors 84 and 102 with a terminal 104 at one end of the secondary winding of the transformer, the other end of which is ground; the contact arm of the switch B which is connected to the ignition breaker by the conductor 92, is connected through the switch contact B2 and conductors 106 and 100 with a switching winding 98, and the contact arm of the switch C which is grounded, connects the distributor of the standard ignition coil 10 through the conductor 108 and the switch to ground.

At this time, a high voltage (spark) is developed by the transistorized oscillator system, using the above described positive feed-back circuit.

With this construction, the push-pull oscillator is used for generating alternating current power. The separate switching winding 98 does not allow a DC. component through the breaker points thus eliminating material transfer or pitting of the points. Premature firing can be controlled by the voltage generated, by the dwell of the distributor and by the contour of the distributor rotor contact. Ah high speeds, the high voltage from the coil remains nearly constant. The current through the ignition breaker set is reduced and thus the life of the breaker points is appreciably extended up to about 300,000 mile life.

A distributor 110 is connected to the end of the standard ignition coil by conductor 112'andis conventionally shown with a plurality of spark plugs '114.

By simply removing the breaker points, a continuous arc may be developed which is ideal for jet engine ignition without mechanical contacts. The essential parts for operating a basically push-pull oscillator is diagrammatically represented in FIG. 2 in which an A.C. arc is generated continuously while the breaker points are open. In this figure, the similarly indicated parts corespond to those already described in connection with the transistorized system shown in FIG. 1, and switching of the push-pull oscillator is accomplished by a separate onoff switch to the battery as shown.

With this type of push-pull oscillator, a continuous high voltage current is built up inthe ignition coil which is connected at its operating end bya conductor 116 with a conventionally shown continuous arc in a spark' plug or a glow tube 118 for use withjet engines.

In both of the systems as described, it may be preferable to initiate operations through a battery and an On-Off switch, but after starting, to'rely upon the transistorized push-pull operation. This ignition for jet engines has the various changes in the construction, combination, and

arrangement of the parts may be made without departing from the spirit and scope of the invention.

I claim:

1. In an ignition breaker circuit system for combustion engines, a battery source of electric current, an ignition coil for the engine, a transformer, a circuit and switch means therein for connecting the source of current through the transformer to the coil, a transistorized push-pull oscillator connected to the source of current and to the transformer primary for exciting the coil to high voltage, the switch means comprising a relay having an energizing winding and a plurality of two-way switches with circuit connectors and operated thereby in one position to connect the ignition coil to the battery, the coil to the ignition breakers, and a portion of the transformer winding to its ground in starting the engine.

2. In an ignition breaker circuit for combustion engines, a battery source of electric current, an ignition coil for the engine, a transformer, a circuit and switch means therein for connecting the source of current through the transformer to the coil, a transistorized push-pull oscillator connected to the source of current to the transformer primary for exciting the coil to high voltage, the switch means comprising a relay having an energizing winding and a plurality of two-way switches with circuit connectors and operated thereby in a second position when the relay is de-energized to connect the ignition coil across the oscillator, the breaker ignition through a portion of the transformer primary winding, and coupling the ignition coil with the transistorized oscillator to develop a high voltage discharge in the ignition breaker.

3. In an ignition breaker for combustion engines, a battery source of electric current, an ignition coil for the engine, a transformer, a circuit and switch means therein for conducting the source of current through the transformer to the coil, an oscillator comprising a pair of oppositely connected transistors in double feed-back circuits with primary transformer windings and feed-back portions thereof, the primary of the transformer having a switching winding portion, switch means and conductors to connect this last winding to ground in starting the torized push-pull oscillator connected to the source of.

current and to the transformer-primary for exciting the coil to high voltage andmeans comprising-a separate winding for thetransformer, an ignition breaker seat connected to the terminal of the'separate winding, and switchmeans operated in starting the enginethroughthe transformer and the ignition coil for standard operation and operative to change the circuit to the ignition means through the transistorized push-pull oscillator after the engine is started.

5. In an ignition breaker system for combustion engines in accordance with claim 4, in which the separate winding is left open or shorted by means of the ignition breaker whereby when the points are closed, the switch means and the winding prevent the flux generated in the primary transformer windings from linking with the feed back windings of the oscillator preventing the latter from being excited or operated.

6. In an ignition breaker forcombustion engines, a

battery source of electric current, an ignition coil for the References Citedin the file of this patent UNITED STATES PATENTS 2,878,298 Giacoletto Mar. 17, 1959 2,976,461 Dilger et a1 Mar. 21, 1961 FOREIGN PATENTS 1,170,981 France Jan. 21, 1959

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