US2072112A - Ignition system - Google Patents

Description

March 2, 1937. w, K 2,072,112

IGNITION SYSTEM Filed July 28, 1932 2.11937 aowz uz.

8.018.113 IGNITION sys'rns William D, Ring, Hoodlum. lass. Application July ll; 1083. Serial No. 025.808 g s claims. (Cl. see-es) This invention relates to improvements in ignicircuit; the condition of the spark 00 adulttion systems for internal combustion enginesand ment of the gap between the pointswhen they particularly to changes in the make-and-break are-opened: number of breaks'per second;.andthe contact members or so'-ca'lled breaker points" in spring tension on the breaker I the,primary circuit of the usual high tension sys- Regardless of the rate of deterioratiom evem 5 terns now used universally for automobile engines; tually the negative breaker point has built up these changes being such as to cause systems: 0! upon it one or more sharp pointed projections. this kind to iunction in an improved manner. while opposite these ill-elections craters are k Although platinum and iridium .wereiormsrly burned out on the positive breaker point. Ap-

10 used icr such contact members. tungsten contact' parently; the spark. which cannot be completely m mem oi the general type shown in Patent No. eliminated irom .between the contact members 1.08M granted March 10, 1914, upon an spin the usual ignition systems, causes tungsten to piioation of William D. Coolidge, have universally be emitted. or vaporized, from the positive breaker superseded them for the reason that they aredess point and the emitted metal moves mm the posi- 15 expensive..wear lo s pdz uire much less attive to thencsative breaker point. to which it be \15 tention. comes attached. aridso iurnishesthe material with the-advent ct high compression engines i'rom which the pointed prol c om becomes within, the last few years. more intense sparks. iormed. Y are required at the spark plugs in the secondary t It appears thatthe growth oi the pointed pro- UNITED t STATES; PATENT OFFICE circuit than formerly. so that higher voltages Jection, in the usual ignition system. is continu I In order" to obtain the necessaryseh ously accelerated because cithe' iollowing aoergyjrom the usual six volt automobile "storage tions:-As the breaker points are separated, air battery greater currents are needed in the pri-H is drawn'in from around the edges or the area or may circuit of the ignition system in which the contact to'iill the partial vacuum created by the breakenpoints are located. This has greatly inseparation of the points. Thisair all rushescressed'thsduty required of the tungstenpoints across the iaces oi'the contact members toward over that required when they were nrst introduced the space between ,the centers oi their areas or and for, some yearsthereatter. because the curcontact, where all the paths oi-travel meet, and rent that must be broken is not onlygreater than where the emitted'material, with which this air a iorlnerly, but thisg'reater current must be broken is illied, is carried, Electrical action at the same 0 many more timeaper second because oi the high time draws the emitted materialto tlle'inegatlve l speed at which such high compression engines t breaker point, towhich it becomes attached. thus are designed to operate. Under present average starting the formation of the above-mentioned @onditions'. the contacts-are made and broken at pointed projection which is usually located near arate 0i than-one hundred times per see-v the center of the initiaharea oi .contactior atthe ond.'and ithasbsenstatedtbatthisratehasbeen center- 0! the contact member, if the contact dncreased on occasions up to as high as tour hun-' members are hat and properly set) .v After the dred times per second. f proiection has started to dorm. the current. behigh duty required oi sueh present day, comes localized at this place on both/breaker,

a tungatsnipoints makes them subject. although to points, and this iurther increases the burning b a loner degree. to the troubles oi the-former aotiong on thetpositive breaker point,'because or platinum and iridium points. except that the reithe increased current density, while the total area iormatioh caused by the hammerihg action is of contact through which currentcan pass is also resisted by tungsten; because of its reduced. Thus the resistance oi the primary cirv u extreme hardness; cuit is gradually increased and the primary cur- Although s me presentday tungsten points oprent is gradually reduced. w'l'hi's reg erate without attention while the automobile in duces the magnetic neld iormed in each cycle which they areusedare driven ior some in the spark coil core. Consequently. when this "of miles, others will. become almgst inoperative lessened iield collapses, as the circuit'is broken so aiter a iew hundred miles. Thisvariation is not between the breaker points, t gradually weaker 0 fully understood but is probably caused by many or spark is produced "at the sparkplug andthe emvariable factors such as. impurities in the tunacie'ncy oi the ignition and the engine is reduced. sten metal or the use of alloys: oilanti dirt on lithisisallowed tocontinue long enoush wlthout the points; action of the remedial attention. the engine will eventually ubridgcdacrolsthepointutheresistanoe'oi the rail to'operate. vr'romtheaboveitwilibeseen of deterioration increases as the current is more and more localized and the current density (and burning) is increased. I

. It is one of the principal objects of the invention to provide a construction in which the rate of deterioration of the breaker points will be much reduced so that, instead of deteriorating through the usual growth of a rou'ghand pitted formation l thereon at or near the center of the contact area,

they will,on the contrary, ,actually improve with use for a'considerable period, after the area of contact between the breaker points has been trued up so as to be suiflciently large and properly located, and which will then not deteriorate so as to give unsatisfactory action until they have been in use several times longer thanthe points in general use.

. the high speedsnow used.

It is another object of the invention increase the speed, certainty and regularityin timing with which the primary circuit is closed at each make overthat heretofore obtained, even with-the points in good condition, in systems operated at A further object is to increase the speed of the break in the primary circuit by increasing the electrical resistance of the emitted material which remains between the contact members after they open, and which resistance is probablylowest between the centers of the areas of contact where this material is concentrated by the partial vac-.

uum formed by the separation of the points.

, In accordance with the object of reduc the rate of. deterioration of the breaker points with use, a feature of the invention consists in a construction in which the material which is emitted from the breaker points is distributed to locations and in amounts such that the undesirable localized formations heretofore referred to, do not occur but in which, on the contrary, the emitted material is distributed in a manner that will usually cause the breaker points to improve with use.

as soon as they are properly trued up and in which the formations heretofore referred to will form much more slowly and-in a larger or much less localized area. Y

In accordance with another object, a feature of I the invention consists in means for reducing, as'

much as possible; the cushioning efi'ect of the air that is partially compressed between the movable .breaker arm point and the stationary breaker point as the breaker arm moves, at'the high rate heretofore mentionedkto complete the "make" in atmospheric air'into the midst of the vapor of the primary circuit. v

In accordance with the object of increasing the electrical resistance of the emitted or volatilized material between the contacts, another feature of the invention consists in means for introducing this material, thereby diluting'it and so increasing its resistance, t

Preferably, and'as illustrated, a single feature of construction accomplishes all of the abovedescribed'objects and embodies the features of the invention just mentioned. Thisfeature of construction consists of a'venyor passage, extending, preferably, from-substantially the center of the contactsurface of one of the breaker points to a location which lies in atmospheric air, whether the breaker points are open or closed. Such a vent breaks the partial vacuum heretofore created in the space between the breaker points as they 'ferred construction.

9,072,112 that the efficiency or the engine probably starts to deteriorate slowly as soon as the breaker points I are first used, so that the average user never ob tains full efllciency from-his engine and the rate separate and changes the paths of travel of the particles of emitted material so that they do not all move toward the center of such space to create a projection. It permits some of the emitted material, produced by the spark that seems impossible to eliminate completely in the usual ignition systems, to pass away from'between the surfaces of contact with some of the air that travels through the vent as this air is being compressed between the points, as they close. Actual tests show that this emitted or vaporized material is condensed onthe walls of the vent, when this vent is in the negative contact, which is the pre-,

emitted material is blown, with another portion Another portion of the of the air being compressed, over the surfaces of the breaker points, where it is caught, by electrical attraction," upon the negative breaker point as the points come together. The remaining, or third portion of this material is blown completely beyond the outer periphery of the breaker points and apparently most of this collects on the cylindrical faces of the breaker points. No one of the separate portions of the emitted material is con- 'centrated in a localized area where it will cause a projection, or projections, to be built up rapidly.

. Therefore, therate of formation of the/projections is greatly reduced, the current is much less localarm which, as it cooperates with the other mem-' her, alternately compresses and rarefles the air between the contact membersr This'clrculation not only carries some of the undesired emitted material away from between the points'butlikewise carries other undesirable material away, such as particles of dirt.

Furthermore, if the breaker points come into contact over an initialarea sufliciently large to provide enough compressed air tofunction as above described, the emitted material will either be dispersed or will be deposited on the depressed portions of the negative contact member outsiclev of the area of, contact to bring such portions slowly up to contact level while the material is being emitted from the relatively spots of tliepositive contact member, so that the area of contact will, at first, gradually increase and the condition of the breaker points, or contact members, will improve-with use. ltis essential, therefore, for the most successful operation of the invention, to inspect new or resurfaced breaker points frequentlyand level oil carefully the portions in contact until a considerable area is in contact, as has been the practice heretofore. After the area of contact has been made to extend completely around the vent, the breaker points will require but little attention oyerlong periodsof time, except to maintain the specified gap between the breaker points.

How the above-mentioned vent in one of the breaker points accomplishes the object of increasing the speed, certainty and regularity in timing of the make" in the primary circuit will now be explained; It has been shown how the compressed air'between. the breaker points escapes through thisvent, carrying with it a certain amount of emitted material; As this airescapes from the space between the contact members, the

cushioning effect of the diminishing amount of remainingairbetweenthesemembersisreduced by a marked degree. Accordingly, the retarding effectoftheaircushionisalsoreducedandthe contact isfmade sooner in each cycle of movement of the movable breaker arm and is thus maintained during a longer period in the cycle, building up a stronger magnetic field in the coil. Upon the collapse of this increased field a spark of more intensityis obtained from the ignition system than heretofore, with conditions otherwise the same. Furthermoreyany tendency for the arm to rebound on the air cushion is avoided heretofore it has been the lowest) and increase the speed of the reak" is obvious.

Another reason for improved operation has been found in the fact that a bright metallic surface is formed upon the contact members which apparently gives a surface having a constant and minimum contact resistance while the resistance of the frosted or matt surface of the usual contact members is higher and more variable because the number and position of the innumerable minute contact surfaces is probably never alike on successive "makes" in the circuit.

All of the factors mentioned co-operate to produce increased power and smoothness of operation of the engine and of the car driven thereby.

For a better understanding of the invention, eference is made to the following description and the accompanying drawing, in which,

Fig. i is a planview of 'a breaker point mechanism in which the present invention is incorporated,

Fig. 2 is a perspective view of a portion of the mechanism of Fig. 1, a portion of the distributor housing being broken away,

Fig. 3 is an enlarged sectional view of the breaker points at the time the points are being separated, with the air circulation indicated by arrows, and

Fig. 41s a view similar to Fig. 3 atthe time the breaker points are approaching each other.

III is a distributor housing in which is positioned a plate I I upon which is mounted the usual circuit breaking mechanism for the primary circuit of a high tension ignition system. A cam i2 is driven through a gearing connection from the internal combustion engine by a shaft which extends through an opening IS in the plate Ii. The cam It operates a breaker arm ll which is mounted on shared pivot I. being retained thereon by the spring cotter II. A fiat spring tends' to move the breaker arm toward the cam l2 and the arm is moved in the opposite direction by the corners of the cam striking a fiber blockfl riveted wire of the primary circuit being connected by thenut 28 andchecknutlltoastudfl whichis insulated from the housing II by the insulating bushing 84 and insulating washer It. The stud a: carries the current to the breaker arm it by means of a metallic button a riveted to the breaker arm spring 2., the tension of the spring maintaining the button I. in electrical contact with a recess in the stud l2.

Adjustment of the breaker gap is accomplished by swinging an arm ll, which carries the fixed breaker point 28, about the same stud I 6 upon which the insulated breaker arm I4 is pivoted. To make the adjustment, a clamping screw 42 is loosened and the arm ll swung about the pivot stud It by turning an eccentric member 44 in the proper direction, after which the clamp screw 42 is tightened.

The above-described mechanism is'all of usual construction and, except where its parts form an element or elements of the combination claimed, forms no other part of my invention.

To accomplish the previously-stated objects of my invention, a vent is located in one of the breaker points, preferably the negative one. is shown, in its preferred form, at it, and consists of an axial hole passing from the center of the contact surface of the movable breaker point, because this is the negative one in this instance, completely through that breaker point and through its support-to the atmosphere beyond. When the fixed breaker point is the negative one. the vent would preferably be located in that one. The diameter of this vent is shown exaggerated inthe drawing for clearness but it should actually be about .040" to .050" in diameter, according to the results of tests already made.

The operation of the invention has already been discussed but its operation may be more fully understood by a consideration of Figs. 3 and 4.

Referring first to Fig. 3. After the breaker points 24 and 26 have been in contact with each other, the breaker arm H moves in the direc tion of the arrow A to separate the points. As they separate, atmospheric air passes through the vent 50 in the direction of the small arrows, breaking the central portion of the partial vacuum which forms between the breaker points as they separate. This air meets, or collides with, the air that rushes in radially in the direction of the arrows a, a, to break the peripheral portion of the partial vacuum. The air between the breaker points contains some tungsten which has been emitted or vaporized from the positive breaker point it and the two colliding currents of air distribute this material. Thus, the air flowing through the vent ll prevents this emitted material from being concentrated in the central area between the breaker points, where it would otherwise be attracted electrically by the negative breaker point :4 to form slowly, in the usual breaker point construction without the vent il. a projection on the negative breaker point; The vapor being diluted by the air passing through the vent has its electrical resistance increased to cause a quicker and more complete break in This vent deposited on the inside walls of the vent, as shown by, actual tests (provided the vent is in the negative contact member as it should be). Another portion of this partially compressed air passes radially in the direction of the arrows b, b. A portion of the emitted material in this air is caught on the negative breaker point 24 where it is, compacted by the blow as the points finally make contact and the remaining portion passes beyond the edges of the contact members and collects on the cylindrical surfaces of these memv here. ,It will be seen that the partially compressed air is allowed to pass freely from 'between the breaker points as they close so that the cushioning effect of the compressed air is greatly re.-

duced, allowing the points to come together more quickly and without rebound. In the above explanation it has been assumed, for clearness, that the breaker points are flat and in contact throughout their entire area. This ideal condition is rarely attained in actual practice when the breaker points are first installed and accordingly, after new breaker points are installed they should be inspected a few times and trued up until an area of contact is obtained that completely encircles the vent 50 and is of sufilcient area to produce the above-described air circulation. This requires no more than the attention which should be given to any newly installed breaker points. After this suihciently extended area of contact completely around the vent 50 has been attained, 40 the breaker points require no further attention for a long period of time. The emitted tungsten collects at the edges of the area of contact on the negative breaker point until it is thick enough to make contact" with the opposite portions of the 45 positive breaker point. This results in the area of contact gradually increasing until substantially the entire area'is' in contact,unless too much emitted material is dispersed, which causes the negative contact member to become slightly concave, so in which case the outer edge only of the area of contact connects with the positive breaker point. Although practically no material is emitted from the central portion of the positive contact member, (as it is opposite the vent where it can make 55 no contact) the projection which is left after the surrounding portions have been vaporized will not interfere with the operation of the device for an exceedingly long time. It is necessary, however, that the gauge by which the gap is adjusted so be so cut away-as to clear this portion of the positive breaker point.

Experiment has shown that, when the vent is in the positive breaker point, no vaporized tungsten is deposited on the walls of the vent 65 and that projections are still formed on the negative point. It is believed, however, that their growth is less rapid than would be the case without the vent. Therefore, as previously stated, it

is preferred to locate the vent in the negative 70 breaker point (whether it is the fixed or the movable one) where the emitted material otherwise tends to collect at its center. As the portion of material traveling toward the center has no place to collect at the center, with a vent at that loca- 76 tion, it passes through the vent where it can cause no trouble. The travel through the vent is aided by the electrical attraction in this case.

' In view of the facts Just stated, certain of the appended claims define the vent as located in the negative contact member or breaker point but, unless thus specified, the claims shouldbe construed to protect constructions in which the vent is located in either breaker point, because some retardation in the formation of the projection on the negative contact member is obtained with the vent in the positive contact member and the reduction of the air cushion between the points, and consequent improved spark at the spark plugs,'is obtained with the vent in either contact member.

Instead of providing an axialvent 50, the vent may consist of one or more grooves cut in the face of one of the breaker points, or of any other suit- 'able construction. Such constructions are intended to be covered by such of the appended claims as can .be construed to cover them, al-

though the construction preferred at present is that illustrated in the attached drawing.

Having thus described my invention, what I claim as new and desire to secure by Letters Patent of the United States is:

1. In a high tension ignition system for internal combustion engines, a pair of relatively movable contact members with substantially flat opposed contact surfaces of substantial area, one

posed contact surfaces of substantial area, the negative contact member having a vent through which atmospheric air may pass to and from the space between the contact surfaces ,upon each separating and each approaching movement, respectively, of the contact members and means to cause said movements to occur alternately in rapidly recurring sequence.

3. In a high tension ignition system for internal combustion engines, a pair of relatively movable contact members with opposed contact surfaces and a vent in the negative contact memher for carrying a portion of the material emitted from the positive contact surface away from between the contact members and acting to cause distribution of another portion of the emitted material over the negative contact surface, whereby any tendency to form a projection of material on either contact surface will be greatly retarded and means to move said contact members relatively to each other a plurality of times per second.

4. The combination, with a pair of relatively movable contact membersoperating in repeated cycles to make and break an electrical circuit with such rapidity that an air cushion is formed between the contact members upon each make" in the circuit, of a vent to permit the cushioned air to escape whereby contact is made earlier in each cycle of motion and thus maintained during a longer period in the cycle.

5. The combination, with a pair of relatively movable contact members operating to make and break an electrical circuit with such rapidity that aoraua volatilisedmaterialremainsinthespacebetween thecontactmembersatalltimeswhiletheyare separated, of a port (or conducting atmosphericing both. the speed and certainty of make,

and'also the time oi! its duration, which consists in expelling a portion oi the entrapped air cushionJonned during the approach of the members, from within the peripheries of the contact surfaces through a vent while another portion escapes between and beyond the outer peripheries of the contact surfaces.

7. In an electrical circuit provided with contact members having opposed contact surfaces which move rapidly relatively to each other to "make" and "break" the circuit. the method of reducing tbetendencytoiorm proi'ectionsoneithercontactsuriacei'romvolatilindmaterialo'iaaid mlnberswhichconsistsinbreaklngthrougha verlthepartial vacuum formedbetween and within the outer peripheries of the contact sur- 8 laces upon the separation 01' the members so as to prevent concentration of said material between thesuriacesandtopermitaportionotthematerial, during approach oi said members, to pass from between said surfaces through said'vent 10 while another portion passes between and beyond the outer peripheries of the contact surfaces.

8. In anelectrical circuit provided with contact members having opposed contact surfaces one oi which has a vent, which contact suriaees move rapidly relatively to each other to make" and' "break" the circuit, the method which consists in distributing volatilined material of said members by colliding currents of air during each separation of said members for reducing the tendency to iorm projections on either contact surface from said volatilind material.

WILLIAM B. KING.

Images