Патент USA US2120492код для вставки
June 14,. 1938. 2,120,492 L. GRAF smmxme PLUG Filed April 1, 1937 ' Inventor." [.60 Gr-(lf P9" PM. A?orne Y. 2,120,492 Patented June 14, 1938 UNITED STATES PATENT OFFICE SPARKING PLUG Leo Graf, OoIogne-Bickendorf, Germany, as _ signor to Karl Werth, Berlin, Germany Application April 1, 1937, Serial No. 134,374 ' In Germany February 17, 1937 5 Claims. (Cl. l23—169) This invention relates to sparking plugs the nut. Underneath the headpiece 3, provided with chief object being to provide a more e?icient the screw ‘thread, there is provided a cup-shaped sparking plug than heretofore. cap l0’ and between the cap and the upper. end of A further object is to provide a construction ' the insulator there is located a spring H or a device having an equivalent action, whilst a 5 washer I! may also be provided. By means of 5 of plug in which particles of oil are substantially prevented from coming into contact with the electrodes. ‘ the spring II the co-emcient of heat expansion A further object is to provide an extension . between the insulator body and the electrode are chamber for the gases in one or each of the elec balanced so that the ignition plug remains per-' trodes, said gas extension chamberbeing at a manently gas-tight. ~ Between the collar 4 and higher pressure than the cylinder chamber dur the foot of the insulator there may be ?tted a ing the compression stroke. - washer l3, for example of asbestos or the like. In acordance with the present invention a The purpose of the washer, in addition to eil'ect- , sparking plug comprises a plug body, an in ‘ ing packing, is also to prevent breaking open of 15 sulator body, a plurality of electrodes, an ex the lower end of the insulator root. This would pansion chamber fora portion of the gases and a be liable to occur easily when, in consequence of gas extension chamber provided in one or each heating, the radially‘expanding collar 4 acts di of said electrodes. Said gas extension chamber rectly on the insulator foot, with the result that radially directed forces may occur in the in may, therefore, be provided in the central elec 20 trode, in the mass electrode, or electrodes, or in sulator foot. Consequently it is advisable to in both the central electrode and the‘ mass electrode, sert the packing disc which, by reason of the ‘10 or electrodes. 25 ' of following the radial expansion of .the collar 4, whilst the‘ internal resistance to deformation of accompanying drawing which shows’by way of example preferred embodiments thereof. the insertion must be so slight that the forces transmitted to the top ‘side of the insertion are less than the allowable radial tension of the in sulator foot. It is advisable to provide the collar 4 with an undercut as shown in Figure 2. In the drawing: Figure 1 is a longitudinal section of the ignition plllg- 30 change of shape on its lower surface, is‘ capable In order that the invention may be more clearly understood reference will nowbe made to the . Figure 2 shows the central electrodeand the . In the foot I of the plug body, provided with a mass electrode, the central electrode being re- _ screw thread, there is a bore for the. reception of cessed at its lower end. ' Figure 3 shows a central section of another form of the mass electrode. 35 Figure 4 shows a vertical longitudinal section of another form of construction of the lower part of an ignition plug according to the invention, and Figure 5 shows ‘another form of construction of 40 the mass electrode. In the drawing like references designate the same or similar parts. In the insulating body I is located the central the mass electrode 9. This mass electrode con sists of a member 9 which, for example, is mount ed on ans-rm II which is enlarged conically out-' wards and then passes into a cylindrical portion I! which engages with a corresponding hole of the foot 8. Opposite to the hole provided for the re ception of the cylindrical part 15 of the mass electrode there maybe provided a further hole 26 in the foot of the plug body. ‘ Immediately above the mass electrode 9 and within the lower part of the central electrode 2, there is provided a recess 2a, this recess forming electrode 2 which, as shown in Figure, 2, is pro- 1 a chamber which communicates by means of an 45 vided at its lower end with a hollow chamber 2a. At the upper end ‘the central electrode 2 engages with the internal screw- thread of a headpiece 3, provided with cooling 'ribs, on the screwed spindle 3a of which there is applied the cable securing >50 nut. At the lower end the central electrode 2 is provided with a collar 4 which presses against the under surface of the insulator foot. _ By means of a ?anged nut 5 the insulator body is secured in the plug body, whilst a copper ring 55 1 is ?tted between the insulator and the ?anged annular. space with the cylinder chamber proper. It will be understood, therefore, that this recess 2a. forms what may be termed an auxiliary gas expansion chamber, or a gas extension chamber, which appears to have the following action in practice. ' The chamber 20. in addition to the chamber 9a in the mass electrode will be herein after referred to as the gas extension chamber. when, for example, in the case of a four stroke engine the piston passes downwardly during the suction stroke, the mixture passes into the cyl 2,120,492 2 inder chamber and into the gas extension cham ber. When the piston moves upwardly for the purpose of compression, the mixture is com pressed in both chambers. In the actual cyl inder chamber there are located in the vicinity of the piston the heaviest moist particles of fuel and above these light combustible products. As the compression of the mixture involves heating and the heating is the more intense the less moist 10 cooling mixture particles are present, the heat ing in the upper part of the cylinder is greater than in the lower part and particularly high in the gas extension chamber in which the combus tion air is entirely free from moist particles by 15 reason of the paths of ?ow. Consequently there obtains, during the entire combustion stroke, in the gas extension chamber a higher pressure than in the actual cylinder chamber, that is to say, the gas extension chamber, during the com '20 pression stroke, blows continuously into the ac tual cylinder chamber with a certain excess pres sure. When now during the upward movement of the piston a particle of oil is projected on the electrodes it is either entirely prevented from 25 coming into contact with the electrodes, and thus forming a short-circuit, by the gases blown through the annular gap, or the oil particle comes into contact with the electrodes but is blown off directly at the same moment so that 30 the formation of a short-circuit oil ?lm between the central electrode and the mass electrode is prevented and ignition can take place during or after reaching the upper dead-centre position of the piston. As the gases which flow through 35 the annular gap between the central and mass ‘ electrodes are particularly hot and particularly easily explodable these are particularly readily ignited by the passing spark and projected in the form of an annular cutting flame outwardly 40 over the spherical mass electrode and thus is nite the other gas mixture located in the actual cylinder chamber. As. the gap no longer ignites the actual cylinder mixture but ignites the par ticularly readily explodable mixture ?owing from 45 the gas extension chamber and this mixture forms an annular cutting ?ame, the ignition ve locity in the cylinder itself is also increased as the annular cutting flame-like ignited mass has a greater ignition effect than the spark which 50 passes. ' The circumstances which have been set out therefore cause, even in the case of cold plugs‘, that is to say when starting, an intensive igni tion and a more efficient utilization of the mix 55 ture. When the electrodes, after a predeter mined time of action, have reached the working temperature the ignition property of the plug is still further increased in that the mixture in the gas extension chamber is from the start 60 hotter, by reason of being heated by the elec trodes, than the mixture located in the cylinder chamber so that the pressure excess of the gases in the gas extension chamber relatively to the actual cylinder chamber and thus the blowing 65 outwardly from the gas extension chamber are further ampli?ed. To the heating of the mixture in the gas ex tension chamber by the heating action of the electrodes there must also be added, as above 70 described, the heating as a result of the com pression so that also in operation, that is to say when the electrodes have reached the working temperature, there obtains a constant excess pressure in the gas extension chamber rela 75 tively to the cylinder mixture and thus any bridging of the spark gap by oil and soot parti cles is prevented. Even in the case of stoppage of the engine for any reason should oil or carbon particles have been deposited on the electrodes these will be blown from the electrode surfaces when start ing the engine at the latest during the second compression stroke prior to the ignition period so that at the latest the second ignition can take-‘place unhindered. Thorough researches 10 have shown that the above mentioned results actually occur in fact and most probably are caused by the explanations set out above, whilst it is not impossible that also other factors play a part. The above explanations only relate to the explanation of the apparently most impor tant point of view of the method of operation of the ignition plug. In Figures 1 and 2 is shown a plug construction wherein the mass electrode 9 consists of a solid ball and only the central electrode 2 is provided with a recess which forms the gas extension chamber. The arrangement may, however, also be such, as shown in Figure 3, namely that the mass electrode 9 is also provided with a recess 9a so that the gas extension chamber is located both'in the central electrode and in the __mass electrode. In certain forms of constructicr’r" the ‘mass electrode may also be so arranged thattn'e ' gas extension chamber is provided therein alone. The mass electrode may be so arranged op posite the central electrode that the mass elec trode lies along the axial extension of the cen tral electrode. The arrangement may also be‘ such that for example two or four spherical . mass‘ electrodes l5 are arranged in a radial di rection relatively to the central electrode I‘! as shown in Figure 4. The central electrode H is then provided with suitable bores l8 which to gether with the right and left parts of the spheri cal surface of the mass electrode l6 form the gas extension chamber. Also in this case the gas extension chamber may be provided either only in the central electrode or in the central elec trode and in the mass electrode, for example by’ providing recesses in the balls of the mass elec— trodes as shown in Figure 3. Figure 5 shows the lower end of an ignition plug wherein the oppositely disposed edges of the cen tral electrode l9 and the mass electrode 20 are . provided with sharp edges for facilitating the passage of the spark. In this case the mass elec trode 20 is provided on an arm 22 pressed from a ring 2|. The ring 2| is ?tted into a suitable groove of the foot 8 of the plug body. As shown in Figure 1 the central electrode 2 is mounted in a hollow space of the insulator which is larger, by an amount necessitated by tol erance, than the external diameter of the central electrode. In the vicinity of its lower edge the (ill central electrode is centered by a ring 23. This ring, in order to prevent the transmission of heat from the insulator foot to the central electrode, may be constructed from a material which is a poor conductor of heat. In the insulator body there are formed by mill ing, pressing or the like cooling ribs 24 and in the surrounding part of the plug body 6 there are provided openings 25 through which cooling air reaches the insulator. In order to prevent the " O foot of the plug body from unnecessarily heating the foot of the insulator there may be ?tted be tween the foot of the insulator and the foot of the plug an insertion of poor'heat conducting 75 material, for example asbestos. ' 3 - 2,120,492 What I claim is:—_ I . 1. A sparking plug comprising a plug body, an insulator body, a carrier at the lower end of said 'trode, said spherical electrode having a recess. therein, said recess being located opposite the re plug body, an ori?ce in said carrier, a rod shaped _ . central electrode, a spherical mass electrode held within the ori?ce in said carrier and disposed op posite to the central electrode, an expansion . chamber for a portion of the gases and a recess ~ in said spherical mass electrode to form a gas ex 10 tension chamber. . ' - 4 2. A sparking plug comprising aplug body, an insulator: body mounted in said plug body, a rod shaped central electrode mounted in said insu cess in thecentral electrode. ~ 4. A sparking plug comprising a plug body, an insulator body mounted in said plug body, a roll-_ shaped central electrode mounted in said insui 5 lator body,a collar on said central electrode, said‘ collar having an undercut recess therein adjacent the insulator body and bearing against said insu lator body, said rod having recesses near the end 10 thereof, and a plurality of spherical electrodes mounted in said plug body,‘ said spherical elec trodes being located one opposite each recess in Jator body, a collar on said central electrode, said . the said central electrode. 15 collar having an undercut recess therein adjacent 5. A sparldng‘plug comprising a plug body, an the insulator body and bearing against said insu~ insulator body mounted in said plug body, a rod sbap'ed central electrode mounted in ‘said insu lator body, acollar on said central electrode, said said plug body, said spherical electrode being 10-‘ collar having an undercut recess therein- adja cated opposite the recess in said central electrode. cent the insulator body and bearing against said 3. A sparking plug comprising a plug body, an insulator body, ‘said rod having receses near the 2.0 insulator body mounted in said plug body, a rod end thereof, and a plurality of spherical elec-‘ shaped‘ central electrode mounted in said insu trodes mounted in said plug body, said spherical lator body, a collar on said central electrode, said electrodes being located one opposite each recess collar having an undercut recess therein adjacent in the said central electrode, each of said spher 25 the insulator body and bearing against said in electrodes having a recess therein, the re sulatorbody,saidrodhavingarecessintheend ical’ cesses in said spherical electrodes being located lator body, said rod having a reces in the end thereof, a spherical earth electrode mounted in thereof, a spherical earth electrode mounted in said plug body. said spherical, electrode being located opposite the recess in said elec opposite the recesses in the central electrode-‘ ' mom. .