USRE21294E - Spark plug - Google Patents

Description

DQC. 12, 1939. w p N 5, JR Re. 21,294

SPARK PLUG Original Filed Dec. 12. 1934 AH! .c; E W Z i} 67Z(Z; y

N V j a 67' 277265 Romance. '12, 1939 g 'R ,21,294

UNITED STATES PATENT OFFICE sniffer Y I 9 Original No. 2,097,460, dated November 2, 1937, Serial No. 757,206, December 12, 1934. Application for reissue October 30, 1939, Serial No.

9 Claims. (Cl. 123-169) My invention relates generally to spark plugs of my invention in a plug of the chambered type; constituting the ignition means of internal comand bustion engines; my invention as to one phase Figure 4, a view in side elevation of a standard thereoi' relating to spark plugs in general, and as form of spark plug of the unchambered type to another phase thereofv to spark plugs of the modified to embody one of the features of my 5 chambered type, such as for example as shown invention. in U. S. Letters Patent No. 1,797,817, granted to In accordance with the particular embodiment Earl E. Bidwell March 24, 1931, wherein the of my invention illustrated in Figs. 1 and 2, the spark produced by the plug ignites a relatively plug comprises a. metal shell 5 open at its opposmall charge of the combustion mixture in a site ends at which it is internally and externally 1o chamber'in the plug separated from, but in threaded, respectively, as represented at 6 and communication with, the combustion chamber 1, the internal thread 6 being provided to receive of the engine in which the main charge is fired, a threaded gland represented at 8 for a purpose whereby the main charge is fired by the jet of hereinafter explained and the thread 'l'being proflame issuing from the chamber in the plug. vided for-the screwing of the plug into the usual 15 One of my objects is to provide a construction threaded hole provided in the cylinder of an inof spark plug wherein accurate adjustment of the ternal combustion engine for receiving a spark electrodes of the plug relative to each other to plug.

produce the proper spacing thereof, one from the J The plug also comprises a center, or core, other, may be efiected with ease and great member 9 of current-insulating material, as for go facility. example porcelain, which seats at its enlarged In connection with another object of my inannular portion In upon an annular seat II in the vention andrelating to the chambered type of interior of the shell 5, the core 9 being held in spark plug, it may be stated that as these plugs place by the gland 8.

have hitherto been provided, both of the elec- The lower end II of the core 9 is of less diam- A trodes are located wholly within the chamber in eter than the space within the shell 5 into which the plug, resulting under certain conditions of this part of the core extends, the core-end I! use, in the befouling of certain of the electrodes reaching short of the bottom of this space, thus by the accumulation thereon of carbon and/or forming, with the shell 5, a chamber l3 into oxide with consequent impairment of the plug for which, it is designed, a portion of the charge of within the chamber in the plug, and which is chamber of the engine to which t p is at lower than that in the main combustion chamber plied, to be fired therein for producing the proof the engine, is not sufficient to maintain the jection of a jet of flame through the lower open electrodes hot enough-to clear them of such beend of the chamber I3 and into the main charge fouling accumulations. in the combustion chamber of the cylinder to It is my object in this connection to provide fire the latter, the opening at the lower end of the I a spark plug of the chambered type in which the chamber l3 and which is restricted as compareo heat generated by the burning fuel in the engine with the diameter of this chamber, being indishall be utilized to an extent sufilcient to maincated at I 4. The size and shape of the chamber tain the electrodes free of carbon and oxide de- [3 and the dimensions of the opening l4 are posits, thereby to insure the proper functioning of such, as shown, as to cause the spark D1 8 the plug, especially under the varied conditions operate with the maximum efliciency and dependpresented by different engines. ability in the firing of the main charge in the Another object is to provide improvements in COmbuStiOh Chamber y means of t e jet o flame spark plugs of the chambered type to the end that Produced the chamber t plu the plug as to its construction, will follow the The electrodes Of this construction are shown lines in general of the standard designs of spark at and the electrode l5 bei g sho'..n as of plugs; d th objects as l b manife t from common form and provided centrally in the core the following description. 9 with its lower end portion ll projecting part Referring to the accompanying. drawing in Way into the Chamber which I have illustrated my invention as em- The electrode l5 p y, is c ed by e b di d 1' r l dlflerent forms of t t metal shell 5, extends across the lower end of Figure 1 is a view in longitudinal sectional elethis Shell and has a Portion i h p oje s vation of a spark plug of the chambered type and pw ly h ou h h pening 4- and into the embodying my invention. chamber ii to a position for proper cooperation Figure 2 is a bottom plan view of the plug of with the electrode portion l1 to form a suitable Fig. 1. spark gap within the chamber l3.

Figure 3 is a view like Fig. 1 of the lower end Preferably the electrodes are so proportioned 01 a spark plug constituting another embodiment and arranged as shown in Fig. 1 that the elecso 0 functioning due to the fact that the temperature combustion mixture enters from the combustion 3 trode portion It extends to a position above the lower extremity of the electrode portion H as shown by dotted lines in Fig. 1, the electrode portion II extending alongside and lengthwise of the electrode portion l1 thereby forming a spark gap extending crosswise of the plug. The electrode It has a portion represented at l9 which extends crosswise of the lower end of the shell exterlorly of the chamber l3 and preferably in suitably spaced relation to the underside of the shell 5 as shown, the portion l8 of this electrode which directly cooperates with the electrode portion I! to form'the spark gap extending upwardly from the portion l9 and through the opening ll into the chamber II.

To provide an electrode Ii having the characteristics above noted, it is preferred that the electrode be provided of general U-shape as shown and above referred to, although other shapes may be employed which are arranged to be in good heat conductive relation to the region just below said end wall. The electrode It as shown is supported in position on the shell 5 by the attachment thereof to the shell 5 at the leg portion 20 of the electrode, the portion 20 which opposes the leg comprising the electrode portion l8, being shown as fitted into a downwardly opening socket 2| in the shell 5.

The provision of the electrode IS with a portion which extends exteriorly of the chamber l3 and in a position in which it is subjected to the heat generated by the burning gases in the combustion chamber of the engine cylinder, as shown and described, is of great advantage in a construction of this kind due to the fact that the electrode Ii becomes the heating element of the device and objectionable deposits of carbon and scale on the electrodes is avoided, it being understood that each time a fresh charge of combustible mixture is introduced into the engine cylinder, (a part of which enters the chamber l3) the electrode l6 becomes covered with the combustible mixture and this electrode being very hot, complete combustion of the mixture on the electrode is effected, upon the firing of. the charge, the adaptability of the electrode I6 for performing as the heating element of the device being 7 augmented by reason of its relatively great length as compared with an electrode located wholly within the chamber of the plug. By the construction shown I am thus enabled to utilize the high heat in the combustion chamber of the engine, and which is considerably higher than that which exists in the chamber I! of the plug, for the maintaining of the electrodes clear of carbon and oxide deposits.

. Furthermore, as will be understood, the electrode I6 is not only subjected to the action of the heat generated by the burning charge, causing it to become heated as stated and minimizing carbonization; but is also subjected to the mechanical force exerted against it by the surging of the vapor into the plug-chamber and the blasting force of the gases ignited in the plug-chamber and discharged through the opening in the plug into the combustion chamber, this force serving to blow off accumulations on the electrode l6 which is directly in the path of the blast.

The spacing of the electrode portion I! from the underside. of the shell 5 is of advantage as should there happen to be a tendency to accumulation of carbon on the electrode It, the danger of such accumulation building up to an amount millcient to span the space between the underside of the shell 5 and the electrode It, thus impairing the operation of'the plug, is avoided.

In accordance with one phase of my invention provision is made for adjusting the electrode 16 relative to the electrode l5 for the pi oduction' of the desired length of spark gap.

In accordance with the disclosure in Figs. 1 and 2, the adjustability referred to is provided for by providing such looseness of fit of. the electrode portion 20 in the socket 2| as to permit the electrode Hi to be rotated about the portion 20 as an axis, but sufficiently tight' to maintain the electrode against accidental displacement from adjusted position, the wall of the opening ll being recessed as represented at 22 to provide the desirable clearance between the electrode portion I8 and the wall of this opening to insure against objectionable bridging by carbon deposits.

By the arrangement shown it is possible to quckly and accurately adjust the electrodes for the desired length of spark gap, such adjustment, when the electrodes sidewise lap each other as shown in Figs. 1 and 2, being readily. and easily effected by sliding a suitable gage stick lengthwise through the opening ll into the space between the electrodes I5 and I8.

It will be noted that in the particular construction now being described the distance between the electrode portions l8 and 20 is substantially the same as that between the electrode portion 20 and the electrode portion ll, whereby the swinging adjustment of the electrode I6 is particularly useful in providing for the desired length of spark gap.

Certain features of the invention may be utilized in a construction in which the cooperating portions of the electrodes instead of lapping sidewise as in Figs. 1 and 2, extend in endwise spaced relation whereby the spark gap extends lengthwise of the plug instead of crosswise thereof.

Fig. 3 shows the plugof Figs. 1 and 2 modified in the particular just referred to and wherein the same numerals are used as in Figs. 1 and 2, the only substantial change being in the provision of the electrode portion l8 as suiiiciently short to extend in the desired spaced relation to the electrode portion IT in the direction of the length of the plug when the electrode is swung to a position in which these electrode portions longitudinally aline.

The electrode adjustment feature as described above in connection with Figs. 1 and 2 may also be utilized in a spark plug of the standard or conventional unchambered type, Fig. 4 showing such a spark plug modified to embody this feature of my invention.

As the details of construction of a standard or conventional plug are well known it is not necessary to describe in detail the plug shown in Fig. 4, it being sufficient to state that the threaded metal shell thereof is represented at 23, the porcelain core at 24, the gland holding the core to the shell, at 25, ,and the central electrode provided within the core 24, at 26.

The other electrode of this plug, in accordance with the present invention is represented at 21 and is preferably of general U-shape shown, its leg portion 28 extending along the side of the electrode 28 as described of the electrode portion 18 in Figs. 1 and 2 and its other leg portion 29 pivoted in a downwardly opening socket (not shown) in the shell 23 to provide for rotatable adjustment of the electrode 21, as described of the electrode 15 in Figs. 1 and 2.

While I have illustrated and described my invention as embodied in several particular forms of construction, I do not wish. to be understood as intending to limit it thereto as the same may be variously modified and altered and the invention embodied in other forms of structure without departing from the spirit oi my invention.

What I claim as new, and desire to secure by Letters Patent, is:

l. A spark plug comprising a shell having a chamber formed therein, a wall portion adjacent the end of said plug providing an end wall for said chamber, said end wall having an opening formed therein adjacent the longitudinal center line of the plug, a central electrode extending into said chamber, and a substantially U-shaped ground electrode extending across the outer side of said end wall to adjacent the central portion of the plug and thence into said chamber to adjacent said central electrode.

2. A spark plug comprising a shell having a chamber formed therein, said shell having a relatively thin wall portion providing an end wall for said chamber adjacent the end of said plug, said wall having an opening formed therein adjacent the longitudinal center line or the plug and of substantially less diameter than the diameter of said chamber, a central electrode extending into said chamber, and a substantially U-shaped ground electrode extending across a substantial portion of the outer side of said end wall to adjacent the central portion of the plug and thence into said chamber to adjacent said central electrode.

3. A spark plug comprising a shell having a chamber formed therein, said shell having a transversely extending wall portion adjacent one of its ends providing an end wall for said chamber closely adjacent the end of said plug, said end wall having an opening formed therein adjacent the longitudinal center line of the plug, a central electrode extending into said chamber, and a substantially U-shaped ground electrode extending a substantial distance across the outer side of said end wall to adjacent the central portion of the plug and thence into said chamber through said opening and into overlapping relationship with said central electrode.

4. A spark plug comprising a shell having a chamber formed therein and providing side walls for said chamber, a transversely extending wall at one end of said shell providing an end wall for said chamber of substantially lesser thickness than the thickness of said side walls, said end wall having an opening formed therein adjacent the central longitudinal line of the plug and'o! substantially lesser diameter than the diameter of said chamber, a central electrode extending into said chamber, and a substantially U-shaped ground electrode extending across a substantial portion of the outer side of said end wall to adjacent the central portion 01 the plug and thence into said chamber adjacent the central portion thereof to adjacent said central electrode.

5. A spark plug comprising a shell having'a chamber formed therein and providing side walls for said chamber, the inner surface 01 said side walls being inclined toward each other and terminating at their lower ends in a transversely extending wall at one end of said shell providing an end wall for said chamber of substantially lesser thickness than the thickness of said side walls, said end wall having an opening formed therein adjacent the longitudinal center line 0! the plug and or substantially lesser diameter than the diameter or said chamber, a central electrode extending into said chamber, and a ground electrode extending across a substantial portion of the outer side of said end wall to adjacent the central portion oi the plug and thence into said chamber adjacent the central portion thereoi and into overlapping relationship with respect to said. central electrode,

6. A sparl: plug comprising a shell having a chamber formed therein and providing side walls for said chamber, the inner surface or said side walls being inclined toward each other and ter= minating at their lower ends in a transversely ex= tending wall at one end of said shell providing an end wall for said chamber and of substantially lesser thickness than the thickness of said side walls, said end wall having an opening termed therein substantially concentric with the longl tudinal center line of the plug and of substan= tially-lesser diameter than the diameter of said chamber, a central electrode extending into said chamber, and a ground electrode extending across a substantial portion of the outer side oi said end wall to adjacent the central portion or the plug and thence inwardly through said opening into said chamber adjacent the central portion thereof and into overlapping substantially parallel relationship with respect to said central electrode.

'Z'. A spark. plug comprising a shell having a chamber formed therein, a wall portion adjacent the end of said plug providing an end wall for said chamber, said end wall having an opening formed therein adjacent the longitudinal center line of the plug, a central electrode extending into said chamber, and a ground electrode ar ranged to be in good heat conductive relation to the region just below said end wall and extending from said shell to adjacent the central portion of said plug and thence into said chamber adjacent said central electrode.

8. A spark plug comprising a shell having a chamber formed therein, said shell having a relatively thin wall portion providing an end wall tor said chamber adjacent the end of said plug, said wall having an opening formed therein adjacent the longitudinal center line or the plug and 01' substantially less diameter than the diameter of said chamber, a central electrode extending into said chamber, and a ground electrode attached to said shell in good heat conductive relation to the region adjacent said end wall and extending to adjacent the central portion of said plug into said chamber in overlapping relationship with said central electrode.

9. A spark plug comprising a shell having a chamber formed therein and providing side walls for said chamber of substantially lesser thickness than the thickness of said side, walls, said end wall having an opening formed therein adjacent the central longitudinal line of the plug and of substantially lesser diameter than the diameter of said chamber, a central electrode extendin into said chamber, and a ground electrode attached to said shell in good heat conductive relation to the region adjacent said end wall, said ground electrode extending across a portion of said end wall opening to adjacent the central portion or the plug and thence within said cham .ber intooverlapping relationship with said central electrode.

WALTER P. m u

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