US1527078A

US1527078A - Spark plug

Info

Publication number: US1527078A
Application number: US340944A
Authority: US
Inventors: Rabezzana Hector
Original assignee: AC Spark Plug Co
Current assignee: Delco Electronics LLC
Priority date: 1919-11-26
Filing date: 1919-11-26
Publication date: 1925-02-17
Anticipated expiration: 1942-02-17

Description

FeB. 17. 1925 1,527,078 H. RABEZZANA, 1

SPARK PLUG Filed Nov. 26, 1919 I j E! 10 v 11 L:

11 i T 8 n 3 3 5 14 4 13 I z a C, C /Q 16 15 awue wfoz HECTOR RABEZZANA Fella ll, l fiho si es HEGTQB RABEZZANA, F FLINT, MICHXGAN, AliSIGNOR TO A C SPARK PLUG COM:- Fw @l FLINT, MICHIGAN, A CCDRPOBATION O'JF MIGHIG'AN.

SPARK PLUG.

Application filed November as, isle. Serial ire/smear.

'To 0132 whmn it may concern."

Be it known that l, HECTOR RABEZZANA, a subject of the King of Italy, and a resident of Flint, county of Grenesee, and State of Michigan, have invented certain new and useful Improvements in Spark Plugs, of which the following is a full, clear, concise, and exact description, such as will enable others skilled in the art to which the invention relates to make and use the same,

reference being made therein to the accompanying drawing, this specification. Q

My invention relates to spark plugs designed for use in connection with internal combustion engines for igniting the combustible mixture supplied to the cylinders thereof; and the principal object of my invention is to provide a spark plug which will be 2G less liable to become short-circuited when in use than has heretofore commonly been the case in spark plugs.

A. further object of myinvention is to provide a spark plug in which such deposit of soot as occurs when the plug is in use will be localized at one portion of the surface of the insulator of the plug, while the remaining portion of the insulator will remain in a comparatively clean condition h and will be free or substantially free from deposited soot when the plug is in use.

With the above and other objects in view, my invention consists in the improved spark plug illustrated in its preferred form in the drawing accompanying and forming a part of this specification; although it will be appreciated that the drawing is for illustrative purpose only, and that my invention includes all such variations and modifications of the particular embodiment thereof shown in the drawing as come within the scope of the concluding claims Referring now to the drawing: Fig. l is a view partly in section and partly in elevation, and in which my improved spark plug is illustrated.

Referring now to the drawing, the refer ence numeral 3 designates a metallic shell or casing the lower portion of which is threaded, asindicated at l, and the upper portion of which is provided with a portion 2 designed to be engaged by a wrench in screwing the plug as a whole into and out of a threaded opening providedin the wall which forms a part of of an internal combustion engine cylinder for its reception.

The shell or casing 3 is provided with an internal chamber 5 which is commonly circular in cross-section, and the inner'end of the casing and of the plug is provided with an opening or passage 6 leading into the chamber 5; and which; opening is of less diameter than the diameter of the chamber. 5, so that the inner end of said chamber ispartially closed by an inwardly extending ledge 7 at the lower end of the casing 3.

The inner end of the insulator above referred to is reduced in diameter as is shown at 8, in order to thereby provide a dead gas chamber or pocket 9 surrounding the portion of the insulator which projects into the chamber 5, as is usual in spark plugs of the type to which my invention relates. The insulator is held. in place within the shell 3 in the embodiment of my invention illustrated by bending over an annular ledge or collar at the upper end of the casing, as shown at 10; suitable cushions 11 being provided between the upper and lower faces of the enlarged central portion 12 of the insulator and the adjacent portion of the metallic shell in order to thereby avoid the breaking of the insulator in turning down the flange 16 to secure the insulator in place. lt will be appreciated, however, that the invention to which this application. relates is in no way involved in or is concerned with the particular manner in which the insulator is held in place within the metallic. casing, and that the same may in fact be held in place in any of the ways at present in use for holding the insulating body of'a spark plug in place in the exterior metallic shell or casing thereof. I

The inwardly extending portion 8 of the insulator is preferably made conical in form, as shown, and the inner end or head 13 of the insulator is larger than the onening 6 at the inner end of the shell; and the peripheral surface of said enlarged inner end is preferably curved in form and substantially spherical iii-shape, or rather in the shape of a segment of a sphere; from which it follows that the peripheral surface of the said enlarged inner end inclines away from the opening 6 adjacent which it lies when the insulator is secured in place within the casing. This enlargement of the till central electrode extending through a passage formed in the insulator, and which electrode is insulated from the shell or casing by said insulator; while the reference numeral 16 designates an external or outer electrode carried by the inner end of the easing and the extremity of which lies adjacent the inner end of the electrode 15, sothat the sparks'will pass between the two electrodes when the plug is in. use. It will be appreciated, however, that the construction of the, plug as regards the outer electrode may be such that the sparks pass from the inner electrode directly to the shell or casing, should such a :form be deemed desirab e, as my invention is not concerned with the articular construction and arrangement of t e outer electrode of the plug.

In view of the premises it will be appreciated that when the plug. is in use there will be a surging of gas through the opening 6 and intoand out from the dead gas pocket 9, due to the alternate high and low pressure conditions present within the cylinder.

The greater part of the flow of gas will be in a direction substantially along the axis of the plug as a whole, as indicated by the arrow at, and such oil, carbon, or other entrained matter as may be present in the gas will be projected directly against the end of the head, where it will be deposited throughout an area corresponding approximately with the area of the passage 6; as the impact of the carbon particles carried by the gas which flows through the opening toward the insulator results in such particles being arrested by the surface of the head 13 with which they contact, where they remain as a deposit upon said surface.

The deposit of soot upon the end of the insulator will be localized upon the exposed end of the enlarged head 13-and will ob viously have little or no effect in short-circuiting the pin while the portion of the insulator beyon or above the area at which the principal part if not all of the soot is deposited will remain comparatively tree from a deposit of soot, oil, or other objectionable material.

Suchgas as may flow through the opening 6 in an inclined direction,-as indicated by the arrow 5, will be deflected by the side wall of the o ening against the end of the insulator, wit a resulting deposit of such carbon particles as the gas in question may carry upon the end of the insulator the same 'us in the case of an axial flow heretotorc considered; while such gas as may be deflected by the head out the insulator and caused to nae-acre flow along the inclined path indicated by the arrow 0 will be deflected by the interior wall' of the chamber 5 against the side of the insulator above the'ledge 14. The quantity of gas, however, not coming into direct contact with the exposed lower surface of the head 13 will be comparatively small, and such carbon as may be swept into the dead gas pocket 9 and deflected against the insulator will be deposited thereupon above the ledge 14; as the construction and arrangement of the parts is such that the impact of such gas as may flow or be deflected along the paths indicated generally by the arrows c with the peripheral surface of the insulator occurs well above the ledge in question.

It therefore follows that by far the greater'amount of soot or equivalent material deposited upon the insulator will be localized upon the under surface of the enlarged head thereof, and that such comparatively small portion as may in fact be carried ast the enlarged end of the insulator and into the dead gas space 9 by the in flow of gas thereinto will be deposited upon the insulator well above the ledge 14 provided by the enlarged head 13; the construction of plug herein disclosed thus maintaining the peripheral surface of the insulator above the ledge 14 comparatively tree from a deposit of soot, and entirely preventing the deposit of soot throu hout a band or zone of some considerable wldth immediately above the said ledge.

Having thus described and explained my invention, I claimand desire to secure by Letters Patent:

1. In a spark plug, a metallic shell or casing having an internal chamber, and an opening of less diameter than said chamber formed in the end of said casing and leading into said chamber; an insulator having a body portion the periphery of which is smooth throughout its entire extent, and

which body portion extends into and is'of less diameter than said chamber, so as to provide a burned gas pocket surrounding said insulator, the end of said insulator being enlarged and lying adjacent the opening aforesaid in said casing, and the peripheral surface of said enlarged end inclining away from said opening; and an electrode carried by said insulator.

2. In a spark plug, a metallic shell or casing having an internal chamber, and an opening of less diameter than said chamber formed in the end of said casing and leading into said chamber; an insulator having a body portion smooth throughout its entlrc extent'extepding into said chamber, and which body portion is or less diameter than the diameter of said chamber, so as to provide a burned gas pocket surrounding said insulator, the extremity of said insulator lying adjacent the opening aforesaid and 1:50

1,627,078 v v e bein enlarged relative to the main body portion thereof, and of smooth convex form throughout its entire extent, to thereby provide a ledge adjacent to the end of said insulator; and an electrode carried by said insulator.

3, In a spark plug, a metallic shell or casing having an internal chamber, and an opening of less diameter than said chamber formed in the end of said casing and leading into said chamber; an insulator having a main body portion conical in form and smooth throughout its entire peripheral surface extending into, and which is of less di ameter than said chamber, so as to provide a burned gas pocket surroundingsaid insulator; the end'of said insulator lying adjacent the opening aforesaid, and being enlarged relative to said opening and the main body portion of said insulator, to thereby provide a ledge adjacent to the inner end' thereof, the peripheral surface of said enlarged end'being convex andinclined away from said opening, and smooth throughoutits entire peripheral surface; and an electrode carried by said insulator.

In testimony whereof I ainx my signature. HECTOR RABEZZANA.