US2819428A - Condenser discharge high frequency ignition system - Google Patents

Description

Jan. 7, 1958 o. E. BowLus ET AL 2,819,428

CONDENSER DISCHARGE HIGH FREQUENCY IGNITION SYSTEM Filed July '7. 1953 5 Sheets-Sheet l1 Jan. 7, 1958 o. E. BowLUs ET AL 2,819,428

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United States Patent -O i CONDENSER DISCHARGE HIGH FREQUENCY IGNITION SYSTEM Omer E. Bowlus and Kenneth A. Graham, Detroit, Mich., assignors to Chrysler Corporation, Highland Park, Mich., a corporation of Delaware Application July 7, 1953, Serial No. 366,426

25 Claims. (Cl. 315-213) This invention relates to a low voltage type high frequency ignition system for internal combustion engines. More particularly, the present invention relates to an automotive vehicle engine ignition system which includes a capacitor discharge circuit associated with the engine ignition distributor and which is adapted to provide a high frequency ignition spark to initiate the combustion process.

This invention has previously been described in copending application Serial No. 286,572, filed on May 7, 1952, now abandoned of which this application is a continuation-in-part.

The operation voltage which is employed in the circuit of the present invention between the power source and the individual spark plug units on the engine is approximately 2,000 volts. In the conventional internal combustion engine ignition systems, the operating Voltage is approximately 12,000 to 15,000 volts. This higher voltage is distributed throughout the entire distributor circuit as well as at the spark plugs.

The frequency of the ignition spark in the present invention is approximately ve megacycles, which is considerably higher than that obtained in the conventional systems. f

An object of the present invention is to provide a condenser discharge spark ignition system for internal combustion engines having a high discharge frequency which produces an ignition current with a steep wave front thereby providing a rapid energy discharge at the spark plug and an instantaneous breakdown of the spark plug gap which in turn results in the successful firing of fouled spark plugs as well as clean plugs.

Another object of the present invention is to provide a condenser discharge ignition system of the type which is adapted to be energized by transformer means which in turn is operated from a source of D. C. supply and of the type in which circuit opening contacts in the transformer primary circuit are adapted to interrupt the source of D. C. supply so that the polarity in the transformer secondary circuit is inherently always of the same sign. If the transformer secondary circuit has the same polarity throughout the operation of the system, it will be possible to impress a negative voltage on the hot electrode (usually the center electrode) in the two-electrode spark plug. Since the high temperature or hot electrode emits electrons more freely than a relatively colder body, a spark can be initiated at a relatively lower voltage across the electrodes when the hot electrode is made negative.

Another object of the present invention is to provide a high frequency ignition system which includes at least a pair of transformer coils and a breaker circuit means for alternately interrupting the current in the primaries of thek transformers wherein the breaker circuit means includes a plurality of breaker contacts, one portion of which is adapted to interrupt thev current in the transformer primaries and the other portions of which are adapted to distribute the flow of primary current to lor 2,819,428 Patented J an, 7, 1958 ice from one or the other of the transformer primaries or' both in such a sequence that the other portion of the contacts is not subjected to arcing. This feature tends to preclude any appreciable amount of metal transfer between the contacts.

According to another feature of the invention, a condenser discharge ignition system is provided in which two transformer ignition coils thereof are adapted to be similarly wound and similarly terminaled and are identical in all respects to each other thereby reducing the problems of assembly and of part replacement.

According to another feature of the invention, a novel condenser discharge ignition system is provided in which the timing is controlled at the breaker points ratherv than at a spark gap provided between the distributor rotor and the fixed contacts in the distributor cover as in the case of conventional distributors.

Another object of the invention is to provide a capacitor discharge internal combustion engine ignition system which has low losses due to stray capacity associated with the wiring harness. This feature will result from the relatively low voltage to which the circuit is subjected. The low voltages handled by the distributor circuit are transformed into high tension voltage only after the electrical energy reaches the individual spark plug transformers. Therefore, complete shielding of the system may be accomplished without appreeiably lowering the spark plug firing voltages and without disturbing engine performance at critical speeds. f

Another object of the present invention is to provide a high frequency capacitor discharge ignition system having at least two ignition coils which are each subjected to an energy storing phase of the operating cycle for approximately of the total operating time. It is also an object to arrange the energy storing phases of the operating cycles for the two coils to cause an overlapping of each other thereby permitting adequate supplies of electrical energy to accumulate and preventing al dropping off of the spark plug tiring voltage at maximum engine speeds. The discharging phase of the operating cycle should be approximately 20% of the total cycle.

In order to realize the foregoing objectives, a spark gap element is introduced into each of the coil circuits which serve as rectifying means to prevent the overlapping phase periods of one coil from interfering with the phase periods of the other and to prevent the discharge of the capacitance in the circuit out of proper sequence. Such spark gaps are as effective as the more expensive rectifier devices or similarly functioning electrical equipment in insulating the two portions of an integrated distributor circuit from each other and also are adapted to provide a substantially instantaneous switching effect where required in the operating cycle. The presence of the spark gaps prevents a discharge of one portion when the other portion is tiring.

Further features, objects, and advantages will either be specifically pointed out or become apparent when for a better understanding of the invention, reference is made to the following written description taken in conjunction with the accompanying drawings in which:

Figure 1 is a view of an assembled automotive distribf utor for the present ignition system;

present ignition system;

Figure shows the timing sequence of the sets of respective contacts in the distributor;

Figures 11, 12, and 13 show oscillograph traces of characteristic voltage curves obtained in the present ignition system;

Figure 14 is a showing of a portion of each of the curves of Figures 1l-13 but to a magnified scale;

Figure 15 is an overall wiring diagram of the preferred form of the present ignition system;

Figures 16 and 17 are modications of the system of Figure l5;

Figure 18 is a section through the spark gap block of the system of Figure 16; and

Figure 19 is a wiring diagram of a two coil distributor circuit having dual breaker points.

This present application for Letters Patent is a conitnuation-in-part of the copending application Serial No. 286,572, filed May 7, 1952.

A preferred embodiment of the present invention is particularly shown in Figures 1 through 15 of the drawings and includes a distributor and a double ignition coil type of ignition circuit which is suitable for use on multicylinder internal combustion engines. The distributor is generally designated by the numeral 10 and is particularly illustrated in Figures l, 2, 3, and 4. The distributor 10 includes a cylindrically stepped casing 12, a mounting flange 14 on the bottom portion of the casing 12, and a shaft 16 which is rotatably mounted in the casing 12 and which includes a depending end. When the distributor is used with a four-stroke cycle engine of the type presently contemplated, the shaft 16 is geared to operate at one-half crankshaft speed. The present invention is particularly suited for use with a V-S automotive engine ignition system in which the shaft 16 rotates one-eighth of a revolution during the time interval between the tiring of the successive cylinders.

The distributor 10 is provided with a vacuum spark advance chamber 18 which is attached thereto by means of one or more screws 20. An oil cup is provided at the side of the distributor, and a detachable distributor cover 22 is secured at the top. The distributor cover 22 has an upstanding spark gap block 24 located centrally thereof and is surrounded by a plurality of ignition leads 26, each of which in turn extends to a separate cylinder of the engine. The cover 22 is detachably held on the distributor casing 12 by means of a pair of diametrically opposed snap clips 28 which are adapted toy permit the removal of the cover 22.

Figures 2, 3, and 4 show the distributor with the cap 22 removed to expose the inner parts of the distributor. The shaft 16 extends upwardly into the upper end portion of the distributor and carries thereon a four-lobed cam 30 and an eight-lobed cam 32, both of which are coupled to the shaft 16 in known manner.

The shaft 16 also detachably carries at its upper end a brush or contact-typerotor 34. The rotor 34 comprises a body portion of an insulating material such as Bakelite and is provided with a conductive metallic bar 36 secured to the top of the body portion by means of a screw 37. A pair of brushes 38 is secured to the outer end of the bar 36 and are spring pressed upwardly, as seen in Figure 3, thereby causing a sliding engagement with a set of fixed contacts 40 which are mounted in the distributor cover. One contact 40 s electrically connected to the igniters in each of the engine cylinders by means of the leads 26. The bar 36 also has an inner portion 42 which slidably engages a contact centrally mounted in the distributor cover 22. The ignition coils which are contem plated for use in the present two-coil type ignition system, are preferably similarly wound, have similarly located terminals, and have identical electrical characteristics. For the purpose of simplifying the assembly of the present ignition system and for purposes of economy of manu-V facture, the two coils may be duplicates of each other.

4 Also it has been found that the ignition coils which are used on the D. C. ignition systems currently employed by the majority of American automotive manufacturers, may be readily adapted for assembly into the present twocoil high frequency system without extensive alteration.

The ignition coils currently in use in the automotive industry on the present type of D. C. ignitionsystems usually have one high tension terminal from the secondary winding, and also two low tension terminals, one of which is connected to the battery side of the coil primary and the other to the breaker point side of the coil primary. It is to the low tension terminal on the breaker point side of the coil primary of one of the two coils in the present two-coil system that a post 44 on the distributor 10 is connected by a suitable conductor 44a. A similar post 46 is mounted on the distributor 10 and is connected to the low tension terminal on the breaker point side of the coil primary of the other one of the two coils by means of a conductor 46a. An internal conductor 44h interconnects the post 44 and a connector bracket shown at 48. Another internal conductor 46h interconnects thc post 46 to another connector bracket shown at 50. The bracket 48 is connected by a spring loaded spiral conductor 52 to a movable electrical contact 54 which is adapted to cooperate with its associated fixed contacts 56. A conductor 58 and a conductor 562' connect the fixed contact 56 to a connector bracket which is shown at 50. The movable contact 54 is mounted at the end of an arm which is cam operated at 59 by means of the eight-lobed cam 32. The connector bracket 48 is connected by means of an internal conductor 60 to one side of an insulated .250 pf. condenser 62. The other side of the condenser 62 is connected to the connector bracket 5() by another internal conductor 64.

The insulating condenser 62 is mounted to a base plate 63 which is mounted for relative rotation with respect to the rotor shaft 16 for the purpose of adjusting the timing. The base plate 63 is grounded to the casing by means of a conductor 65.` A conductive arm 66 having a pair of spaced-apart contacts thereon is mounted for oscillatory movement by means of a conductive spring 68 which is mounted in and grounded through a mounting screw 69 carried by a grounded bracket 70. A conductor 72 is connected at one end to the connector bracket 48 and at the other end to a contact which is opposed to one of the spaced-apart contacts on the arm 66 and combines therewith to form a set of contacts 76. The spring conductor 74 is connected at one end through the conductor 50a to the connector bracket 50 and is connected at the other end to a contact which is opposed` to and combines with the other of the spaced-apart contacts on the arm 66 to form a second set of contacts 78. The radially inner contacts of the pair of contacts 76 is fixed, and the radially inner Contact of the set of contacts 78 is cam-operated at 79 by means of the four-lobed cam 30. The contacts 76 and 78 are preferably formed of silver and are adapted to function as circuit selector contacts which cooperatetin a manner later to be described more fully. A camming motion at 79 in a radially outward direction causes the contacts 78 to close and causes the contacts 76 to separate and open. The camming motion at 79 in the radially inward direction will cause the contacts 78 to open and the contacts 76 to close by virtue of the action of the spring conductor 68.

The contacts 54 and 56 which may be of tungsten, are circuit breaker contacts and have a screw adjustment 80 for controlling the spacing thereof. The circuit selector contacts 76 and 78 have an adjusting screw 82 for adjusting the spacing thereof.

Referring to Figures 5, 6, and 7 of the drawings, a spark gap block 24, which is adapted tobe used with the distributor 10 of the preferred embodiment shown in Figure lthroughlS, is shown in detail and includes a depending member which is threadably received at one cud thereof in the distributor cover 22 and is affixed to' a metallic base 87 for the block 24 at the other end thereof. A pair of spaced .001 pj. condensers 86 and 88 is secured to the spark gap block 24 at opposite sides thereof and includes plates 90 which are connected to a ground terminal 92 which in turn is grounded by means of conductors 94. The condensers also include other plates 96 which are connected to condenser discharge terminals 98 which in turn are connected by means of conductors, one of which is shown at 100, to a secondary output terminal of one of the respective ignition coils. The charged condenser terminal 98 for the condenser 88 has a conductor 102 extending therefrom to a secondary output terminal of the other coil of the two-coil system under consideration. The charged condenser terminal 98 for the condenser 86 has a conductor 104 connecting it to a common plate 105 which supports a pair of spacedapart electrodes 106 and 108 which form respectively with appropriate lower electrodes a set of main electrodes and a set of teaser electrodes respectively. The charged condenser terminal 98 for the condenser 88 has a conductor 110 forming a connection therefrom to a plate 109 which is connected to a pair of spaced-part elec trodes 106 and 108 in a manner similar to the foregoing similarly designated electrodes 106 and 108.

Each set of the main electrodes 106 has a gap therein which is maintained at between 0.025" to 0.041 and adjustable by means of a set of threads which are formed on the outside of the electrodes. The sets of teaser electrodes 108 form a fixed spark gap and are preferably adjusted to 0.015 by means of a set of threads provided on the outside of the lower electrodes of each set 108.

The spark gap block 24 has an insulated casing 112, as seen in Figure 7, which is provided with a bore 114. The bore 114 is open to the atmosphere and is effective to establish communication between the atmosphere and both the main spark gaps and the teaser gaps between the electrodes 106 and 108 respectively. Another bore 116 is formed in the insulated casing 112 and within which the main electrodes 106 are disposed. Both ends of the bore 116 are open to the atmosphere thereby establishing communication between the atmosphere and each of the electrodes 106 and 108. The current carrying capacity of each set of main electrodes 106 far exceeds the capacity of each set of the teaser electrodes 108. The teaser electrodes are arranged to have in series therewith a resistance 108 which function to stabilize the firing of the main electrode 106 at the associated gaps and to ionize the atmosphere surrounding the main electrode gaps immediately prior to firing.

The distributor of the preferred embodiment of Figures lis connected by means of a low tension harness, formed of the individual ignition leads 26 for each cylinder of the multi-cylinder engine, to a plurality of spark plug and high tension type transformer units typified by the one high tension type unit which is particularly shown at 124 in Figures 8 and 9 of the drawings. The transformer unit 124 is contained within a grounded metal tube 1.26 and comprises a long insulating mounting sleeve 128. The lead from the wiring harness 26 termi nates in a conductive spring terminal 130 forming a connection with a lead 134 to one side of a primary transformer winding 136. The winding 136 is wound around an insulating thimble 138 containing an iron core 140. The primary winding is received within a tubular insulator 142 whch has a conductive metallic adaptor 151 at the base thereof. The tubular insulator 142 is Wound with a transformer secondary winding 144 having a turns ratio with respect to the primary winding of 11.2:1 and is commonly connected at one side at 146 tothe primary winding. The common connection 146 is grounded to the grounded metal tube 126 by means of a set of three or more spring positioning clips 148. The secondary winding 144 is connected at its opposite end toa metallic.

f6 adaptor 151 which is secured to the tubular insulator 142.; The adaptor 151 is biased into engagement with a suitable mating conductor by means of a coil spring 158 disposed at the upper end of the tubular insulator 142. The main conductor receives therein a spring clip 152 which is adapted to be removably secured to the upper end of the center electrode 154 of a ceramic spark plug 156. The reaction thrust of the spring 158 is absorbed by a clip 160 which holds an insulator 161 and the insulating sleeve 128 together as a unit.

The operation of the preferred embodiment of the Figures 1-15 is best understood from a consideration of the graphically presented Figures 10, 1l, 12, 13, 14 and particularly the overall wiring diagram of Figure l5. The two-coil type ignition system, according to the preferred form of the invention, has a set of primary and secondary windings 162 and 164 forming the first low tension type transformer or ignition coil 166 and a set of primary and secondary windings 168 and 170 forming the second low tension type transformer or ignition coil 172.

The primary windings 162 and 168 are connected at one end to a common key-controlled ignition switch 174 leading to a battery 176 which is grounded at 178. The primary windings 162 and 168 are connected at their opposite end to the ground 70 by means of the coacting sets of contacts 76 and 78 and the contacts 54 and 56. Each of these contacts are cam-operated as previously explained.

Each of the contacts 76 and 78 function as circuit selector contacts and are alternately opened or closed by the four-lobed cam 30. Contact 76 opens when contact 78 closes, and closes when the contact 78 opens.v

Neither of the contacts 76 or 78 are adapted to be open when the breaker contact points 54 and 56 are open. Except for an instantaneous time of overlap when both sets of contacts 76 and 78 are closed, either one or the other sets of contacts 76 and 78 is always open and it is only under this latter condition that the breaker points 54 and S6 will be opened to interrupt the electrical circuit.

Accordingly, the contacts 76 and 78 are actuated immediately prior to the opening of the breaker points 54 and 56 and are never effective to interrupt the iiow of electrical energy to or from the transformer coils.

vTiming of the ignition system is controlled at the breaker points 54 and 56. Referring to Figure 10, it is seen that both of the low tension type transformers 166 and 172 are being energized immediately prior to reaching the zero degree distributor position. Upon reaching zero degree position the points 54 and 56 commence to separate thereby interrupting the flow of current from the battery 176 through the primary of the -coil 172, conductor 46 through the conductor 58, through the spring 52, through conductor 48, through line 72, and.

then to the ground 70 through the contacts 76. Immediately prior to the separation of the points 54 and 56, ignition current was flowing through both of the primaries 162 and 168 and then to the ground at 70 through the conductors 44, 46, and 58, spring 52, conductors 48 and 72, arm 66, and spring 68. The circuit to the primary 168 is interrupted by the opening of the breaker points 54 and 56 and is held open by the cam 32 during 18 of distributor rotor rotation. Thereafter the breaker points 54 and 56 will close and the primary 16.8 will again be come energized. Throughout the time that the circuit for the primary 168 was being opened and closed, the

primary 162 was continually being energized without in' ananas 7 opening and the closing of the contacts 76 and 78 respectively, occurs substantially at the same instant.

The alternating action of the selector contacts 76 and 78 may occur at any instant during the rotation of the distributor rotor within the additional twenty-seven degrees of rotation previously mentioned. Therefore, the timing of the operation of the contacts 76 and 78 with respect to the operation of the breaker contacts 54 and 56 is not critical and no service problem is involved.

After the distributor rotor undergoes 45 of total rotation from the zero position, the breaker points 54 and 56 are again opened by the cam 32 thereby causing an interruption in the ow of primary ignition current through the coil 162 to the ground 70 through the contact 78. Immediately prior to the opening of the contacts 54 and 56, both the coils 162 and 168 are being energized by theA ignition current owing through the respective primaries and the conductors 44 and 46, the spring S2, the conductors 50 and 74, and the spring 68 to the ground 70. During the time that the breaker points 54 and 56 are interrupting the ignition current in primary 162, the primary 168 is being continuously energized. The contacts 54 and 56 are held open to interrupt the primary current in coil 162 during an additional 18 distributor rotor rotation. When this latter 18 of distributor rotation is completed, the ignition current again commences to energize the primary 162 while at the same time the ignition current in the other primary circuit continues to energize the coil 168.

The induced voltage which is built up in the secondariest 164 `and 170 is impressed across the condensers 86 and 88 respectively, during the opening and closing of the associated primary circuits. It is thus seen that the condensers 86 and 88 are alternately charged in the same sequence as the operation of their associated coils. When a sufficient charge is built up in either of the condensers 86 or 88, the teaser discharge gap between the electrodes 108 is broken down thereby causing a spark to jump across the same. The presence of this spark in the teaser gap is effective to ionize the atmosphere surrounding the discharge gap between electrodes 106 thereby allowing a surge of high frequency current to pass through these electrodes into the distributor 34 to one of a plurality of spark plug loads. A teaser gap and a main discharge gap are provided for each of the ignition coils 166 and 172 and function alternately in the same sequence as the operation of their associated coils.

This same operating cycle continues in this fashion until eight separate condenser discharges occur during one cornplete revolution of the distributor rotor which corresponds to 720 of engine crankshaft rotation thereby causing the tiring of all eight cylinders of the V-8 engine selected for the purpose of illustrating the present invention.

It is to be noted that each of the transformer coils 166 and 172 is absorbing` and continuously accumulating energy for 72 successive degrees of distributor rotation during each quarter turn of the distributor rotor. Accordngly, during 80% of the operating time cach of the coils isstoring electrical energy and during only 20% of the operating time the coils are discharging and releasing this energy.` Because of the fact that ignition coils are continuously accumulating electrical energy during a majority of the operating time, the present invention is particularly adapted for use during high speed operation of the internal combustion engine. If the ignition coils are not continuously energized during a substantial portion of the operating time an insufficient charge will be accumulated prior to the firing of the cylinders.

It is to be further noted that during each successive opening of the breaker points S4 and 56 the current being interrupted is of a different direction than that of the preceding interrupted current. Hence, no appreciable transfer of metal is likely to occur over a period between the tungsten points 54 and 56.

' Because of the fact that the contacts 76 and 78 'open 8 prior to theopening of the breaker contacts 54 and 56, no spark will occur at either of these points. Therefore, the contacts 76 and 78 may be formed of silver since no problems of metal transfer are present.

The secondary windings 164 and 170 of the low tension type ignition coils 166 and 172 may be connected to the respective primary windings thereof at either the battery side or to the breaker point side of the latter, but in the illustrated example shown in Figure l5 the secondary windings are connected respectively at 180 and at 182 to the breaker point side of the windings 162 and 16S in the primary circuit. The output sides 184 and 186 of the secondary coils 164 and 170 respectively are connected by the conductors 100 and 102 to the charged condenser terminals 98 for the pair of spaced apart discharge condensers 86 and 88. A pair of R. F. choke coils 188 and may be provided in the conductors 100 and 102 respectively, to eliminate any radio frequencies which may be generated in the condenser circuits from being fed back into the transformer circuit. When the secondary winding of each of the transformer coils 166 and 172 discharges, a charge is alternately built up across the respective condensers 86 and 88 and also across the respective pairs of the electrodes 106 and 108. It will be appreciated that the magnitude of the charge which is stored up in the ,001 nf. condensers 86 and 88 will be relatively low in comparison to the charge which is capable of beingT stored up in the higher capacity condenser 62 connected between the conductors 48 and 50.

In the operation of the ignition system of the present invention, the voltage on each of the condensers 86 and 88 is allowed to build up to a value which is sufficient t0 alternately re the main gaps 106. Immediately prior to the ring of these gaps, the respective teaser gaps between the electrons 108, as appropriate, tire and ionize the atmosphere adjacent to the main gaps which cause the latter to fire at the comparatively low and stable tiring voltage of 2,000 volts. The main gaps fire alternatively, as previously described, and the energy discharge thereacross is distributed by means of the brush-type distributor 34 to the high-tension type transformer coils 136 and 134 associated with each of the spark plugs. The turns ratio of 11.211 in the transformer windings 136 and 144 causes a step-up in the low tension voltage to an effective voltage between 15,000 and 20,000 volts which is sufiicient to tire each of the plugs 156. The amperage across each spark plug gap is approximately 3 amperes.

The oscillograms reproduced at Figures ll, l2, and 13 represent the characteristics of the voltage across each discharge condenser immediately prior and immediately following the tiring of the spark gap associated with each of the respective condensers. The condensers may discharge several times during the time interval immediately following the opening of the distributor breaker contacts at 54 and 56. It has been found that as many as l5 successive condenser discharges may be produced. Each of the individual discharges, which are graphically represented in Figure l1, produces a separate discharge at the spark plug.

The induced voltage in thc secondaries of each of the distributor coils 166 and 172 causes a voltage rise across each of the respective condensers which is followed by a condenser discharge. When each of the condensers are discharged, the voltage thereacross is reduced to a low value, which is indicated at 194 in Figure 1l. The trans former at the instant that the voltage reaches the point 194 is still discharging and thereupon causes the voltage across cach of the respective condensers to rise again to a new peak value, indicated at 192, in Figure ll. The approximate time which elapses between the occurrence of each of the peak voltages is approximately 250 n seconds. The time elapsing during each condenser discharge, which corresponds to a drop in the voltage cui-ve of Figurell from A196 to 194, is approximately one ,L second. -v

As seen in Figure ll, an oscillatory voltage is set up as at 198 after the previously described series of condenser discharges occur. This oscillatory voltage has a frequency of approximately 660 cycles per second and it continues until such time as the breaker points 54 and 56 close. After the points 54 and 56 close, as indicated at 199 in Figure l1, a highly damped oscillatory circuit results having a frequency of approximately 1660 cycles per second. Under certain conditions, the fixed gaps at 106 and S may fail to deionize after the initial spark and an arc (uni-directional current) will form supplied by cur rent from the discharging transformer. This arc, the picture form of which is brought out in the oscillogram of Figure l2, will persist until the current is insucient to maintain the arc. The condition of the gap electrode surfaces and the type of atmosphere surrounding the gap apparently are the controlling factors in striking and maintaining such an arc.

The number of recurrent sparks obtained during one opening of the breaker points will vary with the voltage and with the energy available from the condenser charging source. The energy available in turn varies with the Voltage of the car battery and with engine speed. The number of sparks which may be obtained is variable depending upon the above-mentioned factors. In the oscillogram shown in Figure 13, only one spark is obtained,

and at the termination thereof an insufficient amount of energy is available to produce another charging curve, as at 196, and the functioning of the condenser degenerates into the 660 cycle oscillation shown at l198 which is in turn followed by the 1660 cycle oscillations commencing with the closing of the points 54 and 56, as shown at 199.

In Figure 14 is shown an oscillogram with a magnified scale which represents the behavior of each of the condensers during the one n second time interval in which the condenser is discharging. During the rising portion of the charging curve shown at 196, which lasts for approximately 250 ,u seconds, the voltage across the discharge condensers is built up to a peak at 192 of approximately 2,000 volts whereupon a rapid spark discharge occurs having a frequency of approximately 5 megacycles. This high frequency discharge is stamped out during the previously mentioned one ,u second time interf val. Thereafter, the spark gaps will deionize provided the conditions are such that this is made possible and the voltage again begins to rise according to the curve 196 across the discharge oondensers. In the case of recurrent spark discharges, this voltage rise will require another 250 ,u seconds.

The high frequency condenser discharge, shown in Figure 14, is duplicated at the spark plugs after the ignition voltage is stepped up by the transformers associated with each of the plugs. This recurrent high frequency spark produced at each plug is particularly suited for igniting fuel mixtures which may be partciularly hard to ignite.

A modified form of the present invention is illustrated by means of a wiring diagram shown in Figure 16. This diagram includes a key control ignition switch 274 which is connected to a battery 276 which in turn is grounded at 278. The switch 274 is connected to a pair of parallel inductances consisting of one separate primary choke 266 and another separate primary coke 272. A condenser 262, which has a capacitance of .250 uf. is connected between the output ends'of the chokes 266 and 272. Two sets of cam operated selector contacts 294 and 296, both of which are grounded at 270, are connected between the output ends of the chokes 266 and 272 in parallel relationship with the condenser 262. One set of cam operated breaker points 254 and 256 are also connected between the output ends of the chokes 266 and 272.

The breaker points and circuit selector contacts inthe modified form of the invention, shown in Figure, 16v, are.

10 similar to the associated breaker points and selector con'- tacts described in connection with the embodiment shown in Figure 15. The circuit selector contacts 294 and 296 and the breaker points 254 and 256 operate in conjunction with one another in much the same manner as spe cified in the preceding embodiment in that each time the breaker points 254 and 256 open, a voltage build-up across either the choke 266 or the choke 272 thereupon becomes available for supplying energy into the balance of the circuit. Also, the circuit selector contacts'294 and 296 are arranged to be opened alternately and selectively with respect to each other as in the preceding embodiment. In other words, immediately preceding the opening of either set there is an instantaneous period of overlap in the cycle during which both sets of contacts are closed. Also, these selector contacts 294 and 296 open so always to precede the opening of the breaker points 254 and 256.

The timing of the system is effected at the breaker points 254 and 256. These points are arranged between the chokes 266 and 272 so that they are subjected to an alternating polarity and for that reason there is no appreciable transfer of metal between these points, which preferably are formed of tungsten.

The voltage alternately builds up across the primary chokes 266 and 272 and is impressed across a primary winding 262' of a low tension type closed core transformer 268. The transformer 268 has a secondary winding 264, one side of which is connected at 298 to the primary winding 262', and the other side of which supplies a brush-type distributor 234 arranged for service in an 8-cylinder engine. A secondary R. F. choke coil 288 and a fixed spark gap 206 in series therewith are interposed between the secondary of the transformer 268 and the distributor 234. A condenser 286 having a capacity of .001 nf. has one side thereof connected between the choke coil 288 and the gap 206 and the other side connected to the ground. A high resistance xed teaser gap 208 is provided in parallel with the main xed spark gap 206 in order to stabilize the operation of the latter.

In operationthe voltage alternately built up across the separate primary chokes 266 and 272 is impressed across the primary winding 262' of the low tension trans` former 268 Whose secondary winding 264 charges the charging condenser 286 to a voltage suicient to ionize` the teaser gap 208 and break down the main discharge gap 206 which allows a surge of high frequency current to pass to the brush-type distributor 234 for further dis.- tribution to the load. In the present instance, the load comprises transformer-type spark plug units, one for each cylinder of the engine and including a high tension transformer, shown at 236 and 244, which is grounded on one side, as indicated at 226, and which fires a spark plug 256. The spark plug and transformer unit is the same as the unit of the preceding Figures 8 and 9, and have a primary to secondary turns ratio of approximately 11.2: 1. The relatively low output voltage on the output side of the low tension type transformer 268 is of the order of 2,000 volts, and is transformed by means of the high tension transformer 236, 244'into a voltage of approximately 15,000 to 20,000 volts which is available at the spark plug 256. Each spark discharge across the gap 206 and its corresponding spark across the spark plug gap 256' have a steep wave front and are characterized by a high' discharge frequency of approximately 5 megacycles.

In Figure 17, the modified wiring diagram there shown,`

corresponds in all major particulars to the diagram of the preceding embodiment of Figure 16 in that it includes a three-point cam-operated switching circuit 394, 396, 354, a low tension type closed core transformer 368, a 4condenser 386, and a spark plug and transformerunit 336, 344, 356. In the embodiment of Figure 17, however, the distributor is of the jump spark type having a rotor 334 which forms two rotating spark gaps between the electrode tip thereof and each of the individual contacts in the distributor cover for the cylinders lof the engine. A main spark gap 306 is provided together with a teaser gap 308. The electrode at the teaser gap has a grounded high resistance therein and moves with the rotor 334.

In the embodiment of Figure 17, the operation is the same as that of the preceding embodiment of -Figure 16, and the timing of the ignition system is likewise effected at the breaker point 354 and 356. The momentary period in which the electrode tip of the distributor rotor 334 passes each fixed contact in the distributor cover is more than sufiicient to transmit the high frequency current to the primary winding 336 of the spark plug transformer unit. A surge of current of the relatively low voltage of 2,000 volts through the gap 306 occurs with a frequency of `the magnitude of approximately megacycles, and a corresponding surge of cur rent of the relatively high voltage of 15,000 to 20,000 volts atn the spark plug 356 occurs with a frequency of the same magnitude of approximately 5 megacyelcs. The resulting spark at the spark gap 356 has a very steep and pronounced wave front. The previously described low tension characteristic is again retained in the embodiment of Figure 17, it being noted that a current with a relatively low voltage of 2,000 volts is distributed by the distributor 334 from the low-voltage-type transformer 36S.

In Figure 18, a spark gap unit comprising a pair of sets of main and teaser electrodes 206 and 208 respectively is shown which is suitable for the embodiment of `the preceding Figure 16 and which, if used in groups of two pairs of sets per system, is also suitable for the multiple fixed gap arrangement of the preceding Figure l5. The main electrodes 206 are adjusted by appropriate movement of the threaded upper electrode thereof to provide a gap at 214 having a measurement of .025 to .041". The set of teaser electrodes 208 is arranged to have an adjustable spaced-apart relationship to provide a gap at 216 having a measurement of approximately .015.

The spark gap unit has an electrode-holding insulating body 224 having a hollow interior 217. The upper electrode of the electrode set 206 is locked in its adjusted position by a locknut 220 which clamps a plate 205 to the top of the insulating body 224 so as to interconnect the upper electrodes 206 and 208. The gaps 2.14 and 216 are disposed in the common chamber provided by the hollow interior 217 of the insulating body 224 which communicates to the atmosphere by means of a vent 215. A metal plate 218 is provided at the base of the insulating body 224 and supports the lower electrode of the main set 206 and also the lower electrode of the teaser set 208 which is adjustably locked thereto by means of a lock nut 222. A threaded depending portion 285 is carried by the plate 218 to provide a means for mounting the spark gap unit at the top of the cover over the distributor rotor 234.

Another modified form of the present invention is shown in Figure 19 which is somewhat similar to the form previously described in connection with Figures l through l5. dual breaker point type as distinguished from the three point systems described previously.

The points 454 and 456 of the present modified form are effective to interrupt the liow of ignition current through the primaries 462 and 468 of the ignition 466 and 472 respectively, and to control the ignition timing. The points 454 and 456 are positioned so that they are opened alternatively with respect to each other. The condensers 462 and 462 are connected between the ground and the breaker point side of each of the coils 472 and 466 respectively and are effective to reduce in the usual manner the tendency of the associated breaker points to arc due to the self-induced voltage in the coil primaries.'

This modified form is of the double coil The coil secondary circuits are identical in most respects to the secondary circuits for the embodiment of Figures 1 through 15 and need not be further described in detail.

Upon interruption of the current flowing through the coil primaries the resulting induced voltage in the associated secondaries alternately charge the condensers 486 and 488. The condensers 486 and 488 discharge through the spark gaps as previously pointed out in connection with the other forms of the invention. It has been found that the current which surges across one set of main gaps and teaser gaps will not break down the other gaps and discharge the other discharge condenser before it causes a spark to jump across those other gaps. It is thus seen that the spark gaps 408 and 406 function in the same manner as the corresponding gaps 108 and 106, shown in Figure l5, to rectify the secondary current. lt is thus seen that the gaps 408 and 406 are effective to eliminate the need for using expensive rcctificrs.

The various embodiments of the invention are shown herein adapted to a high speed 8-cylinder internal coni bustion engine. It is evident that the invention will be equally effective in other multi-cylinder spark engine arrangements, particularly other high speed engines. Also, the drawings show a transformer-type spark plug in which the transformer and spark plug proper are of separate constructions and ultimately fabricated or assem bled together in a common container. However, a transformer-type spark plug can be used in which the transformer windings are actually internally incorporated in the top or porcelain portion of the spark plug itself and thus become a physical part thereof.

The operation of the present invention does not depend upon or require the specific type of spark plug and transformer unit which is illustrated in Figure 8. lt would be possible to employ a standard spark plug or other ignitor means with the present invention and to interpose an independent step-up transformer between the distributor and this ignitor means. Also, it is conceivable that the use of the step-up transformer might be eliminated entirely in those cases where only a small spark voltage is required.

n The spark plug and transformer unit is shown enclosed 1n a grounded metal tube 126, but indeed, it is not essential to the invention that the spark plug and transformer unit be thus shielded. On the other hand, it might be found advantageous not only to shield the spark plug and transformer unit in this manner, but also to shield all the individual leads 26 of the ignition harness. In the latter case, the present invention is particularly advantageous in that the distribution circuits are of the low tension type and therefore, the shielding nrescnts little or' no problem in connection with electrical losses in the system due to stray capacity.

Variations within the spirit and scope of the invention are equally comprehended by the foregoing description.

What we claim is:

1: In an ignition system for an internal combustion engine, a pair of capacitors each having a source of charging power, a plurality of combustion ignitor means, a capacitor-energy distributor for conducting energy to the individual ignitor means in rotation, circuit means connecting one of the respective capacitors and said distributor and circuit means connecting the other of the respective capacitors and said distributor and each said circuit means including an intervening spark gap between the distributor and the corresponding capacitor, and interconnection means effective between said sources of charging power to cause the latter to charge said capacitors and impress a unidirectional voltage and of identical polarity across said gaps alternatively for firing the same thereby causing a corresponding potential to be applied tothe individual ignitor means in rotation in the above described manner and having the same polarity for all said ignitor means.

2. For use in an internal combustion engine including therewith a plurality of fuel ignitor means, a pair of alternately charged capacitances, means forming pluralities of spark gap paths different ones of which are connected to and lead from each of said capacitances, and a common switch in series with said pluralities of spark gap paths for distributing energy from said capacitances in rotation to successive ones of vsaid ignitor means, said pair of alternately charged capacitances having means providing an unidirectional ow of energy thereto for alternately charging the same with Voltage charges of like sign.

3. In an internal combustion engine ignition system having a fuel ignitor means, a source of electrical energy, and a distributor mechanism for distributing electrical energy from said source to said ignitor means; a circuit means interconnecting said power source and said distributor mechanism; said circuit means comprising a pair of ignition coils, breaker means for opening and closing composite portions of said circuit means in a predetermined operative sequence thereby causing a voltage to be alternately and successively built up in said ignition coils, a capacitor electrically connected to said ignition coils and adapted to be energized thereby, and a main spark gap means comprising a pair of main arcing terminals, one of said terminals being connected to said capacitor and the other of said terminals being connected to said distributor mechanism, said capacitor being operative to discharge electrical energy through said spark gap means to said distributor mechanism, said spark gap means including teaser arcing terminals connected in parallel with respect to said main arcing terminals.

4. In an ignition system for an internal combustion engine, an ignition coil primary circuit and a secondary circuit including a pair of primary windings and a pair of secondary windings respectively, each of said primary windings being electrically coupled to a separate one of said secondary windings, a source of electrical potential operatively connected between said primary circuit and ground for energizing said primary windings, breaker means for opening and closing separate portions of said primary circuit in a predetermined operative sequence to alternately deenergize said primary windings whereby an induced voltage is alternately built up in said secondary windings and whereby one of said primary windings is continuously being energized during the time interval in which the lother is being deenergized, said secondary circuit including a pair of capacitors, a separate one of said capacitors being connected between each secondary winding and ground, interconnecting one portion thereof and the ground, a rectifying means connected to one side of each of said capacitors, and means connected to said rectifying means for distributing ignition current throughout the ignition system, said capacitor being adapted to discharge a high frequency ignition currenty through said rectifying means.

5. The combination as set forth in claim 4 wherein said rectifying means comprises a pair of main electrodes spaced apart to form a main spark gap therebetween,'

and a teaser electrode connected in parallel across said main electrodes to form a teaser spark gap to initiate an arc across said main electrodes at low voltage.

6. In an ignition system for an internal combustion engine, an ignition coil primary circuit including two said windings, a source of electrical energy operatively connected between said primary circuit and ground for energizing said windings, breaker means for opening and closing said primary circuit in a predetermined operative sequence thereby alternately deenergizing said windings, a secondary circuit including at least one winding elec trically coupled to said primary circuit and a capacitor interconnecting said secondary circuit winding to ground,

a spark gap means connected to only one side of said capacitor, and a means4 connected to said spark gap means for .distributing ignition current throughout the .r

A.14 ignition system, said ignition current passing across said spark gap means'in only one direction, said capacitor being adapted to discharge a high frequency ignition cir# cuit through said spark gap means, said spark gap means comprising a first pair of electrodes spaced apart to form a main spark gap therebetween, and a teaser spark gap formed between a second pair of electrodes connected in parallel with respect to said iirst pair of electrodes and in close proximity thereto, said teaser gap being of a smaller dimension than said main gap.

7. In an ignition system for an internal combustion engine, an ignition coil primary circuit, an ignition coil secondary circuit electrically coupled to said primary circuit, a source of electrical potential operatively connected between said primary circuit and ground, breaker means for opening and closing separate portions of said primary circuit in a predetermined operative sequence, said secondary circuit including a capacitor interconnecting one portion thereof and ground, a spark gap means connected toone side of said capacitor, and a means connected to said spark gap means for distributing ignition current throughout the ignition system, said capacitor being adapted to discharge a high frequency ignition circuit through said spark gap means, said spark gap means comprising a first electrode means having spaced apart portions forming a main spark gap therebetween, a second electrode means defining a teaser spark gap, said second electrode means being connected in parallel with respect to said first electrode means and in close proximity thereto, said teaser gap being of a smaller dimension than said main gap, and an electrical resistance connected in series with said second electrode means.

8. In an ignition system for an internal combustion engine, a pair of ignition transformer coils including primary and secondary coil portions, a pair of ignition current rectifying means, a secondary circuit means interconnecting a separate one of said pair of rectifying means with each of said secondary coil portions, a primary circuit connected to` said primary portions and including circuit breaker points therein, a source of electrical potential connected between said primary portion and ground, a iii-,stv rotary cam means for actuating said breaker points, said primary circuit further including con' tactmeans for alternately connecting each of said pri-A mary coil portions to ground, a second rotary cam means for actuating said contact means, said breaker points and said contact means being adapted to alternately and separately deenergize each of said primary coil portions while the other primary coil portion is being energized, and a pair of capacitors, a separate one of said capacitors being connected between each of said secondary portions and ground, said secondary coil portions being effective to produce an induced voltage to charge the capacitors thereby causing a surge of current to alternately pass through each of said rectifying means.

9. In an ignition system for an internal combustion engine having an ignition current distributor and source of ignition current, a pair of ignition coils, an ignition transformer coil, a circuit connecting said coils with said source, breaker means interposed in said circuit for successively interrupting the same, electrical contact means interposed in said circuit for reversing the polarity of said ignition transformer coil portion, said contact means being adapted to be actuated immediately prior to the breaking of the circuit by said breaker means, a secondary coil circuit electrically coupled with said ignition transformer coil and interconnected with said distributon a main spark gap interposed in said secondary circuit, and a capacitor connecting said secondary circuit to the ground, said distributor including therein a plurality of xed contacts and a rotary electrode, said main spark gap being formed between said rotary electrode and said fixed contacts. A'

l0. The combination as set forth in claim 9 wherein said distributor has disposedtherein a second teaser electrode rotatably mounted in parallel relationship with respect to said first mentioned rotary electrode, said teaser electrode cooperating with said rotary electrode to form a teaser spark gap in close proximity to said main spark gap.

11. ln an automotive ignition system, a pair of capacitors each having a source of charging power, a plurality of spark plug transformers, a capacitor-energy distributor for conducting energy to the individual spark plug transformers in rotation, `circuit means connecting one of the respective capacitors and said distributor and circuit means connecting the other of the respective capacitors and said distributor and each said circuit means including an intervening spark gap between the distributor and the corresponding capacitor, and interconnection means effective between said sources of charging power to cause the latter to charge said capacitors and impress a unidirectional voltage and of identical polarity across said gaps alternatively for firing the same thereby causing a corresponding potential to be applied to the individual spark plug transformers in rotation in the above described manner and having the same polarity for all said transformers.

12. In an automotive ignition system, a pair of capacitors each having a source of charging power, a plurality of spark plug transformers, a capacitor-energy distributor for conducting energy to the individual spark plug transformers in rotation, circuit means connecting one of the respective capacitors and said distributor, and circuit means connecting the other of the respective capacitors and said distributor and each said circuit means including an intervening spark gap between the distributor and the corresponding capacitor, and interconnection means effective between said sources of charging power to cause the latter to charge said capacitors and impress a unidirectional voltage of identical polarity across said gaps alternatively for firing the same thereby causing a corresponding potential to be applied to the individual spark plug transformers in rotation in the above described manner and having the same polarity for all said transformers, each said circuit means further `including a stabilizing spark gap in parallel with the first named gap thereof for stabilizing the firing voltage of the same in order to cause the individual potentials applied to all said spark plug transformers to be uniform.

13. In an automotive ignition system, a pair of capacitors each having a source of charging power, a plurality of spark plug transformers, a capacitor-energy distributor for conducting energy to the individual spark plug transformers in rotation, circuit means connecting one of the respective capacitors and said distributor, and circuit means connecting the other of the respective capacitors and said distributor and each said circuit means including an intervening spark gap between the distributor and the corresponding capacitor, interconnection means effective between said sources of charging power to cause the latter to charge said capacitors and impress a unidirectional voltage and of identical polarity across said gaps alternatively for ring the same thereby causing a corresponding potential to be applied to the individual spark plug transformers in rotation in the above described manner and having the same polarity for all said transformers, each said source of charging power being formed` of windings including an energizable input winding in parallel with the other energizable input winding of the other source of charging power, and circuit means for connecting said paralleled input windings to a common energy so-urce including sets of contacts cooperating to cause the substantially continuous storing of energy in the input windings and adapted to be recurrently opened according to predetermined sequence to cause the sources of charging power each alternatively to make available to the corresponding capacitor the stored energy in the respective input coil thereof.

14. In an automotive ignitiond system, capacitance asi-9,428

means, a plurality of spark plug transformers, means comprising switching means for conducting energy from the capacitance means to the individual spark plug transformers in rotation and including a series spark gap effective therein, means for supplying charging power for the capacitance means and including transformer secondary winding means for recurrently impressing a voltage on said spark gap and said capacitance means for building up the potential on the latter and causing the same to discharge through the spark gap and apply a corresponding potential to the spark plug transformers, means including a pair of parallel similar windings adapted to cause voltages to be induced across said transformer secondary winding means upon being energized, and circuit means for connecting said paralleled windings to a D. C. energy source and including sets of contacts cooperating to cause the substantially continuous storing of said source energy in the paralleled windings, one said set of contacts being adapted to be opened in predetermined sequences with respect to the others to open circuit said windings alternatively from said energy source, thereby successively interrupting currents of different directions.

15. In an automotive ignition system, capacitance means, a plurality of spark plug transformers, means comprising switching means for conducting energy from the capacitance means to the individual spark plug transformers in rotation and including a series spark gap effective therein, means for supplying charging power for the s capacitance means and including transformer secondary Winding means for recurrently impressing a voltage on said spark gap and said capacitance means for building up the potential on the latter and causing the same to discharge through the spark gap and apply a corresponding potential to the spark plug transformers, means including a pair of paralleled similar windings adapted to cause voltages to be induced across said transformer secondary winding means upon being energized, and circuit means for connecting said paralleled windings to a D. C. energy source and including sets of contacts cooperating to cause the substantially continuous storing of said source energy in the paralleled windings, one said set of contacts being adapted to be opened in predetermined sequences with respect to the others to open circuit said windings alternatively from said energy source, thereby successively interrupting currents of different directions, said transformer secondary winding means being of two-part construction, one said part thereof and one said paralleled winding cooperating to form a first transformer and the other said part thereof and the other said paralleled winding cooperating to form a second transformer.

16. ln an automotive ignition system, capacitance means, a plurality of spark plug transformers, means comprising switching means for conducting energy from the capacitance means to the individual spark plug transformers in rotation and including a series spark gap effective therein, means for supplying charging power for the capacitance means and including transformer secondary winding means for recurrently impressing a voltage on said spark gap and said capacitance means for building up the potential on the latter and causing the same to discharge through the spark gap and apply a corresponding potential to the spark plug transformers, means including a pair of paralleled similar windings for causing voltages to be induced across said transformer secondary winding means upon being energized, and circuit means for connecting said parallel windings to a D. C. energy source and including sets of contacts cooperating to cause the substantially continuous storing of said source energy in the paralleled windings, one said set of contacts being adapted to be opened in predetermined sequences with respect to the others to open circuit said windings alternatively from said energy source, thereby asians successivelyinterrupting currents, of ,different directions, said transformer secondary winding means and said capacitance means each being of two-part construction, one said secondary winding part and one said paralleled winding cooperating to form a first transformer for charging one said capacitance part and the other said secondary winding part and the other said paralleled winding cooperating to form a second transformer for charging the other said capacitance part.

17. For use in a multicyli-nder engine having a spark plug and transformer unit for each cylinder thereof,v a pair of alternately charged capacitances, means forming pluralities of spark gap paths `differentones `of which are connected to and lead from each` of said capacitances,y and ya common switch in lseries with said pluralities of spark gap paths for distributing energy from said capacitances in rotation to successive onesr of said spark plugl and transformer units, said pair of alternately charged capacitances having means providing a unidirectional ii'ow of energy thereto for alternately charging the same with voltage charges of like sign.

18. For use in a multi-cylinder engine having a spark plug and transformer unit for each cylinder thereof, a pair of alternately charged capacitances, means forming pluralities of spark gap paths connected to and leading from said capacitances, and a common `switch in series with said pluralities of spark gap paths for distributing energy from said capacitances successively to alternate ones of said spark plug and transformer units, said alternately charged capacitances each having energy providing means providing a unidirectional flow of energy ythereto and cooperatingl with the other energy providing means for alternately charging the capacitances with potential charges of like sign, both said energy providing means having a common source of D. C. power in series therewith.

19. For use in a multicylinder engine having a spark plug and transformer unit for each cylinder thereof, a pair of alternately charged capacitances, means forming pluralities fof spark gap paths connected to and leading from said capacitances, and a common switch in series with said pluralities of spark gap paths for distributing energy from said capacitances successively to alternate ones of said spark plug and transformer units, said alternately charged capacitances each having energy providing means providing a unidirectional liow of energy thereto and cooperating with the other energy providing means for alternately charging the capacitances with potential charges of like sign, both said energy providing means having a common source of D. C. power in series therewith, and comprising a pair of paralleled transformers.

20. In an electrical ignition system for a multicylinder engine having a spark plug and transformer for each cylinder thereof, a source of D. C. power, first and second primary windings, and circuit means for connecting said first and second primary windings to said power source such that the former are in parallel with one another, said circuit means including one set of contacts and other sets of contacts, said other sets of contacts being effective to close and open in alternation, when said one set of contacts is closed, for storing energy in said prim-ary windings a majority of the time, all sets of contacts aforesaid having cam means establishing cooperation in timed relation thereamong to open said one set of contacts and alternately open circuit, said energy storing first and second primary windings; the combination with said first and second primary windings, of secondary winding means forming therewith first and second transformers respectively, a capacitance connected to the first transformer and a capacitance connected to the secon-d transformer so as to be charged in sequence with the aforesaid stored energy when the respective first and second primary windings thereof are alternately opencircuited, a switch means for distributing energy to the spark plug and transformer for each cy'linder in rotation, and circuit means connecting each said capacitance and said switch means and yhaving a common portion, said circuit means including a spark gap between each said capacitance and said common portion for preventing the discharge from one capacitance due to breakdown of the spark gap associated therewith, to interfere with the charging of the other capacitance.

2l. In an electrical ignition system for a multicylinder engine having a spark plug and transformer for each cylinder thereof, a source of D. C. power, first and second primary windings, and circuit means for connecting said first and second primary windings to said power source such that `the former are in parallel with one another, said circuit means including one set of contacts and other sets of contacts, said other sets of contacts being effective to close and open in alternation, when said one set of contacts is closed, for storing energy in said primary windings a majority of the time, al'l sets of contacts aforesaid having cam means establishing cooperation in timed relation thereamong to open said one set of contacts and alternately open circuit said energy storing first and second primary windings; the combination with said first and second primary windings, of secondary winding means forming therewith first and second transformers respectively, a capacitance connected to the first transformer and a capacitance connected to the second transformer so as to be charged in sequence with the aforesaid stored energy when the respective first and second primary windings thereof are alternately open-circuited, a switch means for distributing energy to` the spark plug and transformer for each cylinder in rotation, and circuit means connecting each said capacitance and said switch Ameans and having a common portion, said circuit means including a main spark gap between each said capacitance and said common portion for preventing the discharge from one capacitance due to breakdown of the spark gap associated therewith, to interfere with the other capacitance, said circuit means further including stabilizing gaps one in parallel with each main gap for making uniform the firing voltage necessary to cause breakdown of the main gaps.

22. In an electrical ignition system for a multicylinder engine having a source of D. C. power, first and second primary windings, and circuit means for connecting said first and second primary windings to said power source such that the former are in parallel with one another, said circuit means including one set of contacts and other sets of contacts, said other sets of contacts being effective to close and open in alternation, when said one set of contacts is closed, for storing energy in said primary windings a majority of the time, all sets of contacts aforesaid having cam means establishing cooperation in timed relation thereamong to open said one set of contacts and alternately open circuit, said energy storing first and second primary windings; the combination with said first and second primary windings, of secondary winding means forming therewith first and second transformers respectively, a capacitance -connected to the first transformer and a capacitance connected to the second transformer so as to be charged in sequence with the aforesaid stored energy when the first and second primary windings thereof are alternately open-circuited, spark plugs of a number corresponding to the number of cylinders in `the engine, each said spark plug having a voltage step-up transformer therefor for increasing a relatively low voltage to a voltage high enough to fire the spark plug, switch means for communicating a relatively low voltage to the spark plug transformers in rotation, and circuit means connecting each said capacitance and said switch means and having a common portion, said circuit means providing for the impression of a relatively low discharge voltage from each said capacitance upon said switch means and including a spark gap between each capacitance aforesaid and said common portion for essere@ 19 preventing the discharge fromone capacitance due to breakdownl of the spark gap associated therevvith to change the charge on the other capacitance.

23. In an ignition system for an internal combustion engine, a pair of primary coil windings, a source of electrical potential, said primary windings being connected in parallel with one side thereof being connected to one side of said potential source, a tirst circuit branch connecting one of said primary windings to the other side of said potential source, a second circuit branch connecting the other of said primary windings to said other side of said potential source, first breaker elements for interrupting said first circuit branch and second breaker elements for interrupting said second circuit branch, means for separating said first breaker elements While simultaneously closing said second breaker elements and for separating said second breaker elements while simultaneously closing said iirst breaker elements, a third circuit branch interconnecting the other sides of said primary windings, third breaker elements disposed in said third circuit branch, and means for alternately separating and closing said third breaker element while said first breaker elements are closed and while said second breaker elements are closed.

24. In an ignition system for an internal combustion engine, a pair of primary coil windings, a source of e1ectrical potential, said primary windings being connected in parallel with one side thereof being connected to one side of said potential source, a first circuit branch con necting one of said primary windings to the other side of said potential source, a second circuit branch connecting the other of said primary windings to said other side of said potential source, first breaker elements for intert 2G riiiit'igisaidhrsteireuittbi'anch and second breaker elements for interrupting'lsaid second circuit branch; means for separating said first 4breaker elementsj while simultarieoiislyI closing'fsaidlsecond breakerelements and for separ'atiri'igl's'aid*second breaker elements while simultaneoilslyfclosinglsaid first breaker elements, a third circuit branchlinterconneting the other sides of said primary windingsgithird':breaker elements disposed in said third circuit branch, means for alternately separating and clos- A ingsaid-` thirdbreak'er element while said first breaker elements 'are' closed andwhile said second breaker elements are closedi'a pair'f secondary coil windings, a separate one of said 'secondary windings being electrically coupled to each of said primary windings, a pair of capacitors, one side of each4 oliv-said capacitors being connected to ground, each of the 'other sides ofsaid-capacitors being connected to a separate' one of ysaid secondary windings, a combustion ignitor means',ja:fourth and' a fifth circuit branch respectively connetingeachff-said othersides of said capacitors tosaid igniter means, and a spark gap means interposed in each of `said fourth and fifth circuit branches.

`25. The combination as set forth in claim 24 wherein said spark gapnieans'includes a pair of main electrodes defining a main spark gap and a pair of teaser electrodes in yclose proxirnityv` to said main electrode forming a teaser spark 'lgapf References Cited in the le of this patent UNITED STATES PATENTS v2,197,114 Rabezzana et al. Apr. 16, 1940 2,447,377 l Tognola et al. Aug. 17, 1948 2,515,370 Hooven July 18, 1950 U. S. DEPARTMENT OF COMMERCE PATENT OFFICE CERTIFICATE OF CGRRECTION Patent No., 819,428 January f75 1958 Omer E0 Bowlue et ala It is hereby certified that error appears in the printed specification of the above numbered patent requiring correction and that the said Lettere Patent should read as corrected below.

Column 8, linev 35, for "electrons" read me electrodes en; column 9y line 58, for "parteularly" read particularly m; line 65, for "coke" read choke column l0, line 16y after "so" insert as im; column 13, line l0, for "an" read a me.,

Signed and sealed this 15th day of April 1958o (SEAL) Attest:

KARL Hf MINE ROBERT c. wATsoN Attestlng Officer Comnssioner of Patents

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