US2394768A

US2394768A - Ignition system

Info

Publication number: US2394768A
Authority: US
Publication date: 1946-02-12
Anticipated expiration: 1963-02-12

Description

Feb. 12, 1946.

J. R. HARKNESS IGNITION SYSTEM Filed Oct. 31,

, I I I I I v I 1 v I I I I I I I I I! mm?! 0 n n v 4 Inventor Joseph R. Har'hness,

Hus Attornsg.

Pa tented Feb. 12,

2,394,768 IGNITION sys'rsM Joseph R. Harimess, Scotia, N. Y., assignor to General Electric Company, a corporation of New York Application October 31, 1941, serial No. 411,370

17 Claims.

This application relates to ignition systems and in particular to such systems utilizing relatively low voltage distribution.

An object of my invention is to provide an improved ignition system.

Another object of my invention is to provide an improved low voltage distribution ignition system utilizing a transformer arranged adjacent the spark plug for providing high voltage to the spark D 118.

A further object of my invention is to provide an improved converter system.

A still further object of my invention is to provide an improved transformer device for use in a low voltage distribution ignition system.

Further objects and advantages of my invention will become apparent and my invention will be better understood from the following description referring to the accompanying drawing, and the features of novelty which characterize my invention will be pointed out with particularity in the claims annexed to and forming part of this speciflcation.

In the drawing, Fig. l is a schematic diagram of a low voltage distribution ignition system embodying my invention; Fig. 2 is a longitudinal sectional view through a combined condensertransformer-spark plug provided with features of my invention; and Fig. 3 is a sectional view taken along line 3-3 of Fig. 2.

Referring to the drawing, I have shown a magneto provided with a rotatable magnet Ill which is adapted to react electrodynamically with a stationary core H of magnetic material about which a primary magneto coil I2 is inductively arranged. The primary magneto coil I2 is connected across a condenser l3 and the terminals l4 and i5 of a breaker mechanism which is adapted to be operated by a breaker cam i6 mounted on a shaft ii.

The shaft I1 is arranged to be rotated at a predetermined speed relative to the speed of rotation of the magneto rotatable magnet III. The magneto also is provided with a secondary winding I 3 arranged on the magneto stationary core member II and inductively related to the primary winding i2. The terminals of this secondary magneto winding are connected to ground at l9 and to a rotatable distributor arm which is adapted to complete an electric circuit with a plurality of distributor points 2|, each of which is connected to a low voltage distribution cable 22. The magneto provides a source of electrical power supply which forms part of a converter system and is connected through the distribution cables 22 to a unit which comprises a combined condenser, transformer and spark plug. This unit is provided with-a cylindrical casing 23 of electrically conductive material having a substantially closed end 24 at one end thereof and a threaded collar 25 at the other end thereof which is arranged to engage a complementary threaded portion of a spark plug shell 26. Each distributor cable or lead 22 is insulated and extends through an opening 21 formed in the end 24 of the casing 23 and is electrically connected at 28 to one side or terminal 29 of a fixed electrical discharge or spark gap 3|] which is formed between the terminal 29- and another side or terminal 3| of the spark gap. The

terminals

29 and 3| are held in spaced apart relationship by an insulating member 32 formed with a definite opening in the central portion thereof, and this provides a definite or fixed spark gap between the spark gap terand a spring seat 35 on the inner side of the casing end 24. This compression biasing spring provides an electrical grounding connection for the fixed spark gap 3| through the casing 23. In order to supply a sufiiciently high voltage to provide an electrical discharge across the spark gap of the spark plugs of this system, a transformer is provided which is connected directly to each spark plug. The primary of this transformer is formed by a condenser including a plurality of sections formed by thin electrically

conductive plates

36 and 31 insulated from each other by thin layers of

insulating material

38 and 39 such as paper and are wrapped in cylindrical form about a sleeve of insulating material 40. The two con

denser sections

36 and 31 are connected across the fixed spark gap 30 in such a manner that current flowing in the condenser will be substantially in the same direction in all sections thereof.

This arrangement is effected by grounding the outer end of the outer condenser section 36 by electrically connecting it to the electrically conductive casing 23 through a lead 4| and electrically connecting the inner end of the inner casing to a distributor point 2| and the outer side or terminal 29 of the fixed spark gap 30 by an electrical conductor or lead 42. The secondary of the transformer is formed by a secondary winding 43 which includes a conductor wound on a core ll of insulating material and is connected at one end thereof to a distributor point 2| through the fixed spark gap terminal 29 and a distributor lead 22. The other end of the secondary winding 43 is connected to a terminal contact element 45 secured in the insulating core 44. The core 44 may be formed as a molded element and the fixed spark gap terminal 29 is provided with a threaded or knurled projection 46 about which the upper end of the core 44 is molded so as to provide a rigid support for the terminal 29 on the core. A spark plug is mounted in the lower end of the casing 23 and includes a spark plug electrode 4'! formed on the end of an electrical conductor 48 which extends upwardly through a core 49 of insulating material, such as porcelain, and is provided with an upper contact terminal element 50 arranged in electrical contact with the transformer secondary terminal 45. The upper end of the spark plug insulating core 49 and the terminal 50 extend within the lower portion of the insulating sleeve 40 and an inwardly extending annular flange or collar 5| formed on the shell 26 extends within a complementary groove 52 formed in the insulator 49 for retaining the insulator and the spark plug electrode in predetermined fixed position within the shell 26. The unit including the fixed spark gap, the transformer, and the spark plug is adapted to be mounted in the cylinder block of an internal combustion engine and is provided with a terminal supporting sleeve 53 which is threaded at its upper portion 54 and threadedly engages a complementary threaded portion 55 formed on the lower end of the shell 26. The supporting sleeve 53 is threaded on its outer surface and is adapted to be secured in a complementary threaded opening in the engine block, thereby providing a rigid support for the spark plug unit and providing a good electrical grounding connection for the various parts of this unit. The spark plug is provided with a plurality of grounding terminals or electrodes 56 which form an integral part of the mounting sleeve 53 and are spaced apart from the spark plug electrode 41 to provide the desired spark plug discharge gap therebetween.

In this system, the voltage generated in the magneto secondary coil i8 may be from about 800 t 1600 volts and is distributed at this relatively low voltage to the different spark plug units. The fixed spark gap 30 is constructed such that it will break down at some voltage lower than the peak magneto voltage at the lowest operating speed. When an electrical discharge takes place between the fixed spark gap electrodes 29 and 3i, current circulates around the condenser sections in substantially the same direction in all sections thereof, thereby inducing a voltage in the transformer secondary winding 43. In this manner, the condenser provides the dual functions of a condenser connected across a fixed spark gap and is inductively arranged about the transformer secondary winding to provide a primary for the transformer. With this construction, the fixed spark gap can be sealed and, if desired, an inert gas can be placed within the surrounding space within the casing 23 and a seal can be provided about the distributor lead 22 where it enters the sleeve 23'. Furthermore, since all high voltage is confined to the inside of the transformer spark plug unit, this unit can be filled with some insulating wax or oil, if desired, and radio shielding of the leads from the distributor to the spark plug unit may be entirely eliminated or made much less critical than in a high voltage distribution ignition system.

While I have illustrated and described a particular embodiment of my invention, modifications thereof will occur to those skilled in the art.

I desire it to be understood, therefore, that my invention is not to be limited to the particular arrangement disclosed, and I intend in the appended claims to cover all modificat ons which do not depart from the spirit and scope of my invention.

I What I claim as new and desire to secure by Letters Patent 01' the United States is:

1. An ignition system including a source of electrical power supply, a spark plug. a transformer secondary winding connected to said spark plug, a condenser arranged about said transformer secondary winding, means for connecting one side of said condenser to said source or electrical power supply, and means for connecting the other side of said condenser to ground.

2. An ignition system including a source oi electrical power supply, a spark plug, a transformer including a secondary winding connected to said spark plug, a primary for said transformer including a condenser inductively arranged about said transformer secondary winding such that the passage of current in said condenser induces a voltage in said secondary winding, and means for connecting one side of said condenser to said source of electrical power supply.

3. An ignition system including a source of electrical power supply, a spark plug, a transformer including a secondary winding connected to said spark plug, a primary for said transformer including a condenser arranged about said transformer secondary winding such that the passage of current in said condenser induces a voltage in said secondary winding, means for connecting one side of said condenser to said source of electrical power supply, and means for connecting the other side of said condenser to ground.

4. An ignition system including a source 01' electrical power supply, a spark plug, a transformer secondary winding connected to said spark plug, a condenser arranged about said transformer secondary winding, 9, fixed spark gap, means for connecting one side of said condenser to said source of electrical power supply and to one side of said spark gap, and means for connecting the other side of said condenser to the other side of said spark gap and to ground.

5. An ignition system including a source of electrical power supply, a spark plug, a transformer including a secondary winding connected to said spark plug, a primary for said transformer including a condenser having a plurality of sec tions arranged about said transformer secondary winding and being provided with terminals such that the passage of current in said condenser will be in substantially the same direction in all sections thereof, and means for connecting one side of said condenser to said source of electrical power pply.

6. An ignition system including a source of electrical power supply, a spark plug, a transformer including a secondary winding connected to said spark plug, a primary for said transformer including a condenser inductively arranged about said transformer secondary winding such that the passage of current in said condenser induces a voltage in said secondary winding, a fixed spark gap, means for connecting one side of said condenser to said source of electrical power supply and to one side of said spark gap, and means for connecting the other side of said condenser to the other side of said spark gap and to ground.

7. A transformer including a primary and a secondary winding, said primary including a condenser inductively arranged about said secondary winding such that the passage of current in said condenser induces a voltage in said secondary winding.

8. A transformer including a primary and a secondary winding,- said primary including a condenser having a plurality of sections inductively arranged about said secondary winding such that the passage of current in said condenser induces a voltage in said secondary winding.

9. A transformer including a primary and a secondary winding, said primary including a condenser having a plurality of sections arranged about said secondary winding and being provided with terminals such that the passage of current in said condenser will be in substantially the same direction in all sections thereof.

10. A transformer including a primary and a secondary winding, said primary including a condenser having a plurality of sections insulated from each other and from said secondary winding and inductively arranged about said secondary winding such that the passage of current in said condenser will be in substantially the same direction in all sections thereof and will induce a voltage in said secondary winding.

11. A converter system including a fixed electrical discharge gap, means including a source of electrical power supply for providing electrical impulses to said electrical discharge gap, a transformer having a secondary winding, and a primary for said transformer including a condenser inductively arranged about said secondary winding and connected across said fixed discharge gap.

12. A converter system including a source of electrical power supply, a fixed electrical discharge gap, means for connecting said fixed gap across said source of electrical power supply, a

transformer having a secondary winding, a prielectrical power supply, a fixed electrical discharge gap, means for connecting said fixed gap across said source of electrical power supply, a transformer having a secondary winding, and a primary for said transformer including a condenser having a plurality of sections arranged about said secondary winding and being provided with terminals connected across said fixed gap such that passage ofcurrent in said condenser will be in substantially the same direction in all sections thereof.

said casing, means for connecting one. side of said spark gap to said casing, a transformer in said casing having a secondary winding connected to the other side of said spark gap, a primary for said transformer including a condenser arranged about said transformer secondary winding such that passage of current in said condenser induces a voltage in said transformer secondary winding, and a spark plug having an electrode in said casing connected to said transformer secondary winding.

17. A converter system unit including a casing, a spark gap device having two sides arranged in said casing, means for connecting one side of said spark gap to said casing, a transformer in said casing having a secondary winding connected to the other side of said spark gap, 9. primary for said transformer including a condenser arranged about said transformersecondary winding such that passage of current in said condenser induces a voltage in said transformer secondary winding, means for connecting one side of said condenser to said other side of said spark gap, means for connecting the other side of said condenser to said casing, and a spark plug having an electrode in said casing connected to said transformer secondary winding.

JOSEPH R.