US2223151A

US2223151A - Ignition system for internal combustion engines

Info

Publication number: US2223151A
Authority: US
Publication date: 1940-11-26
Anticipated expiration: 1957-11-26

Description

Nov. 26, 1940. 4c. s. NAD'LER ET A1. 223,151

IGNAITION SYSTEM FOR INTERNAL COMBUSTlONv ENGINES Filed Dec. 30, 1959 www WW ATTO R N EYS ,Mil

Gil

Paf-entedNov. 26, 1940 lUNITED STATES IGNITION SYSTEM FOR INTERNAL COMBUSTION ENGINES Charles S. Nadler, Brooklyn, and Emil Kameny,

Richmond Hill, N. Y., assgnors to Standard Motor Products, Inc., Long Island City, N. Y., a corporation of New York Application December` 30, 1939, Serial No. 311,772 5 Claims. (Cl. 1 23-148) This invention relates to a novel ignition system for internal combustion engines, and the object and purpose of this invention is to provide means for delivering to the engineduring the' starting operation a spark which is hotter and stronger than the normal running spark, including automatic control means whereby a spark of the intensity vof the normal running spark is reestablished a short time after the engine has started and is maintained during the period of engine operation. A further object is to provide a hotter and stronger spark without the use of auxiliary relays, batteries or cells, and by use of a device which is compact, satisfactory for its itntended purpose, and inexpensive to manufacure. v

A-t the time of starting an internal combustion engine, in the wiring arrangements now in common use, the closing of the starting switch causes a heavy drain on the batteries and consequently a considerable drop in voltage across the battery terminals. .This condition continues as long as the starting switch is closed. As a result, during this period, the voltage applied to the ignition system is correspondingly reduced and in consequence the ow of current in the primary windingof the coil is of less intensity and the cur- -rent induced in the secondary winding of the coil produces a weaker and thinner spark wi-thin the cylinder. As is well known, the starting phase is the 'timeat lwhich the strongest spark isrequire in the cylinder, because of the necessity oi `ig ting raw, cold, and overriched gasoline r mixture.

This invention is particularly directed to affording meansvfor maintaining an increased current through the primary winding of the coil at the moment of starting and for such period of time vthereafteras to allow for delay inv ring and for the length of time which sometimes' elapses, 'particularly when engines are cold, during which they mustbe crankedlby the starter before combustion occurs. Furthermore, according to this invention, the length of time during which the spark of increased intensity is maintained can be established by the design and size and relationship of the parts, so as to permit establishment "of any desired length of time Within certain outside limits.' Fur-ther, the invention affords means responsive to the temperaturejof the surrounding air, whereby the length of this period of intensified spark may be prolonged when the temperature of the surrounding air is low' andshortened when the temperature of the surrounding air is'high. By this means current intensication is afforded over a longer starting period when the weather is cold, and over a shorter starting period when the weather is warm, the latter saving unnecessary wear and tear on the points and condenser due to the intensiiiedl current.

Referring to the drawing which forms a part of this specification: 1

Fig. 1 shows diagrammatically the standard wiring circuit of the electrical system of a. modern automobile, with the invention which is the subject of this application incorporatedthereim Fig. 2 is -a vertical section of a device embodying certainl elements of this invention Fig. 3 is a vertical elevation showing the device of Fig. 2- secured to the outer shell of anignition coil.

The one terminal of a battery IIl'is connected to a relatively heavy cable II, the other end'of which is connected to one of the stationary contacts ofa starter switch I2. The otherstationary contact of starter switch I2 is connected to one terminal of the motor M, the other terminal of which is connected to the ground. The opposite terminal of the battery is connected to the ground, thus a'ording a circuit whereby energy is transmitted from the battery through the closed starter switch I2 and through motor M and returned to ground. This circuit isclosed when the internal combustion engine is being. cranked to inducecombustion to begin in the cylinders.

Connected with some convenient point of the cable II is an ammeter I4. The'opposite terminal of the latter is connected with ignition switch I3 and the opposite terminal of the latter is, in accordance with thisinvention, connected with terminal I5 of the device hereinafter to be described. The opposite terminal I 6 of said device is connected to the terminal I1 of a coil 2i, the opposite terminal I8 of which is connected to one terminal of the interrupter I9. The opposite terminal of the interrupter islconnected to ground, and a condenser 2U isA bridged around the interrupter contacts in the usual well-known manner. Current flows in the circuit just de' scribed when the ignition switch I3 is closed and In. the primary ignition circuit, according to the present invention, there is'interposed a device comprising a ballast resistor '25, adapted to be normally connected in series with the other 5 elements of the primary circuit described above, and, in association therewith, a heat-responsive -thermostaticswitch 26 bridging the terminals I5, I6 and, when closed, arranged to shunt the currentv through a path of low resistance around 10 the ballast' resistor 25, and a heating resistor 21 adapted to be energized when the ignition i switch I3 is closed, and spaced in such mechanical relationship (hereinafter more fully described) with switch 26 as to afford a means for 1 causing said switch to open after expiration of a. period of time determined by the heat output of heating resistor 21 and the rate of heat transferred from it to switch 26 at the prevailing temperature of the surrounding atmosphere,

,Referring to Fig. 2, switch 26 is preferably made of a bimetallic unit vcomprising two sheets or discs of metal having different coefcients of expansion, secured together and mounted upon a supporting post 28. Terminal members is, ls are positioned at either side of post 2s, the inner ends of these terminal members being formed as stationary lcontact elements adapted to engage either with the bimetallicunit or with raised portions 29 secured thereon. Preferably the post 28 and the terminals I5, I6 are secured in xed relation by being molded into a hardened block 30 of molded insulating material such as, for example, phenolformaldehyde resin. Switch 26 is so arranged and adap-ted as to close when the temperature in the neighborhood of the bimetallic unit falls below a predetermined temperature, and to open' when said temperature rises above a predetermined temperature- In order to bring the'hea-ting resistance 21 into 40 uitable relationship with thermostatic switch '26,

it is preferable to mount resistor 21 upon a spoolshaped member 3|, preferably of porcelain. For convenience, the ballast resistor 25 may be similarly mounted upon a spool-shaped member 32, and both spools 3|, 32 may ber supported upon a headed bolt 33 secured by a nut 34 tothe bottom of a container 35.'

The casing 35 may be made oi' sheet aluminum or other material having` heatconducting properties suited to the purpose. It is initially fornied with a closed bottom and an open top. In the assembly thereof, bolt 33, with spools 3|, 32 thereon, is rst secured through .a central opening in the bottom of the casing by means of the nut- 34, and suitable electrical connections are provided for the resistors. Preferably connecting 'means are provided from terminal I5 to one end of' each of resistors 25- and 21; the opposite end of resistor 25 is connected to terminal'IG and the opposite end of resistor 21 is connected to the casing 35 which is grounded to the car chassis.

Casing35 may be formed vwith a circular indentation 36 serving as a seat or rest for block 30, so arranged and positioned as to afford the .65- eXact desired spacing of switch 26 from heating it from turning. To further secure the block in position, and to render the assembly watertight, the upper edges 38 of the casing are then swaged over to assure a tight and permanent fit of the parts. A suitable mounting bracket 39 maybe 5 provided.

The result of the above construction is to form a small airtight chamber within casing 35 in which there is imprisoned a small body of air. The temperature of this air is responsive to heat 10 produced in the heating resistor 21, as modified by greater or less loss of heat by conduction through the walls 35., For example, if the thermostatic switch 26 should be arranged to remain closed so long as the temperature of the air around it is below 100 F. and to open when the said temperature exceeds 100 F., then in cold weather the heat produced in heating resistor 21 would bring about a closing of switch 26 after a greater length of time than it would in warm 20 weather.

Preferably, the parts are so arranged and related that at mean temperature the switch 26 will open approximately 20 seconds after ignition switch I3 has been closed, and that the length of this period of time will be increased as the weather is colder and decreased as the weather is warmer l than the mean temperature.

Aprimary ignition circuit, including the primary winding of the coil and across the interrupter contacts, and at the same time through the heating resistor 21 which is in parallel with the portions of the primary ignition circuit mentioned. Assuming heating resistance 21 toV be cold at the 40 time switch I3 is closed, thermostatic switch 26 is therefore closed, and the initial current directed through the primary ignition circuit will pass from terminal I5 through switch 26 to terminal I6, thus being shunted around the ballast 45 resistor 25. Accordingly, the full available voltage of the battery is impressed across the primary winding of coil 2|, and this full available voltage is maintained until thermostatic switch 26 opens.

Upon the closingof ignition switch I3, current 50 flows through heating resistor 21. Because of the mechanical arrangement of the parts already described, and shown particularly'in Fig. 2, the heat produced by resistor 21 is 'communicated to the imprisoned body of air within casing 35 and this 55 body of air rises in temperature at a rate governed to a substantial degree by the rate of heat-loss through the walls of the casing-i. e.,- by the temperature of the surrounding atmosphere. When the imprisoned body of air in'the neighborhood U0 of the bimetallic unit reaches the critical temperature, switch 26 opens and thereby inserts ballast resistor 25 into the circuit passing through the primary winding of coil 2|. When the ballast resistor 25 is so inserted in the ignition circuit, 65 a portion of the IR drop takes place within ballast resistor 25, thereby reducing the voltage applied across the terminals of the primary winding within the coil. As long as the ballast resistor 25 remains in circuit, the voltagewithin 70 the coil. is reduced.

. The arrangement is, therefore, adapted to check excessive voltage in the primary winding of the coil, and hence at the interrupter points and in the condenser, after a short period at to be connected in parallel with said first-menstarting which may be longer in cold weather than in warm weather; and to provide means whereby an intensified current is passed through the primary winding of the coil and through the in-- terrupter contacts, during this short period at starting. For practical purposes and at average temperatures, vwe have found that itis desirable that such intensication of the currentv should be maintained for approximately twenty seconds after the ignition switch has been closed. The mechanical arrangement of parts shown herein is conveniently adapted to procure response of the thermostatic switch after approximately that length of time. -The arrangement is such that in cold weather, due to rapid conduction of heat from'the body of air within casing 35 to the outv side atmosphere, the period of response of thermostatic switch 26 Ais lengthened, thereby resulting in a prolongation in cold weather of the period during which the ignition current is intensiiied.

While there is described herein 'one convenient form of device embodying this invention, and the one which is at present believed to be the best form, it is our intention that this in vention` shall be deemed to cover and include all forms and shapes and sizes of device, whether the same be located within or without the coil casing, as fall within the terms of the annexed claims.

We claim:

1. For use in an ignition system which includes an ignition switch a coil having a primary winding and a source ofelectrical current, the combination` of a current-limiting resistor adapted to be connected in series with the primaryv winding of said coil and to limit the flow of current through said winding when so connected, a thermo-responsive switch adapted to open when the temperature of the atmosphere in which said switch is positioned increases above a predetermined temperature and arranged, when closed, to conduct current to the primary winding of said coil through a path having less resistance than is provided by said current-limiting resistor, and an electrical heating resistance adaptedv to be connected in parallel with the primary winding of said coil and to be energized when said ignition switch is closed, said heating resistance :being adapted to supply heat tending to raise the temperature of the atmosphere in which said thermoresponsive switch is positioned.

2. For use in an ignition system which includes a resistor, the combination of a closed casing whose walls consist at least in part of heat conducting material, a conned body of uid enclosed within said casing and in contact with the walls thereof, a' stationary switch contact member, a thermo-responsive movable switch contact element positioned within said body of iluid and adapted to move relatively to said stationary contact member to separate said switch contact members in response to increase in the temperature of the fluid in contact with said movable element above a predetermined temperature, and an electrical heating resistance positioned within said body of fluid and adapted whenl energized tioned resistor and to dissipate heat into said iiuid at a predetermined and substantially fixed rate, whereby actuation of said movable switch member will be delayed for a length of timeafter energization of said resistance` dependent upon the rate of dissipation of heat from said fluid through the casing walls to the surrounding atmosphere.

3. For use in an ignition circuit which includes a source of electrical current, an ignition switch, and the primary Winding of a coil, the combination of a closed casing whose Walls consist at least in part of heat-conducting material, a current-limiting resistor adapted to -be vconnected in said circuit in series with said primary winding when the ignition switch is closed, a thermo-responsive switch positioned within said casing and connected in parallel with said resistor and adapted to be connected in series with said primary winding, and a heating resistance positioned within said casing in thermal relationship with said last-mentioned switch, said heating resistance being adapted to be connected acrossthe source of current in parallel with said current-limiting resistor and the primary winding of said coil when the ignition switch is closed.

4. For use in an ignition circuit which includes a source of electrical current, an ignition switch, and the primary winding of a coil, the combination of a closed casing whose walls consist atleast in part of heat-conducting material,

a current-limiting resistor adapted to be con' nected'in said circuit in series with saidA primary winding when the ignition switch is closed, a thermo-responsive switch positioned within said casing and connected in parallel with said resistor and adapted to be connected in series with said primary winding, saidv current-limiting resistor beingl positioned within said casing in Ithermal relationship with saidv last-mentioned sistor adapted to be connected in said 4circuit in series with said primary winding when the ignition switch is closed, a thermo-responsive switch positioned within said casing and connected in parallel with said resistor and adapted to be connected in series with'said primary winding, and a heating resistance positioned within said casing in thermal relationship with said last-mentioned switch, said heating resistance being adapted to be connected across the source of current in parallel with the primary winding of said coil when the ignition switch is closed.

CHARLES S. NADLER.

EMIL KAMENY.