US 2871388 A
Description (OCR text may contain errors)
Jan. 27, 1959 P. F. ADAIR SPARK GAP ELECTRODE Filed Jan. 16, 1957 INVENTOR PAUL F. ADA/R BY MW MJ/Pm ATTORNEY United tates Patent SPARK GAP ELECTRODE Paul F. Adair, Bayshore, N. Y., assignor to let ignition Co., Inc., Larchmont, N. Y., a corporation of New York Application January 16, 1957, Serial No. 634,578
2 Claims. (Cl. 313-141) This invention relates to a spark plug assembly, and particularly to a spark gap electrode having a core of sodium or other materials through which heat can be readily dissipated.
Heretofore, one of the major problems in the design of spark plugs has been the heating effect on the electrodes by the spark causing pitting of the electrodes and faulty ignition. To alleviate this difficulty, it has been proposed to provide a spark plug which defines a constricted passage, with the gap between the electrodes being located in this constricted passage or ignition chamber, and a head or insert disposed in the end of the constricted passage opening toward the associated cylinder having helical passages establishing communication between the ignition chamber and the associated cylinder.
In a spark plug of the above described character, the combustible mixture is propelled through the helical passages of the head into the ignition chamber causing swirling of the mixture therein. This swirling action serves to improve the spark plug performance. Although this construction reduces the pitting of the electrodes, the heating effect still causes deleterious effects on the ignition pattern in the engine.
Accordingly, it is an object of this invention to provide a core of material within the electrode having means for rapidly dissipating heat from the electrodes.
In the preferred form of the invention, the inner core of the electrode is composed of sodium which will absorb the heat from the outer metal shell of the electrode, thereby reducing the heat intensity on said outer shellso as to lengthen electrode life of the spark plug and improve ignition characteristics.
In one aspect of the invention, the spark plug assembly includes a hollow body having a cylindrical internal space which defines an ignition chamber. Two axially aligned and spaced apart electrodes are mounted in the central portion of the cavity. One of the electrodes comprises a hollow shell with a core therein composed of a material through which heat is rapidly dissipated. Helical passages connecting the cylindrical internal space with the exterior of the assembly are also provided.
These and other objects, features and advantages of the invention will become apparent from the following detailed description and drawings which are merely exemplary.
In the drawings:
Fig. 1 is an elevational view, partly in cross section,
2,871,388 Patented Jan. 2?, 1959 illustrating the electrode of my invention in the preferred form of spark plug assembly; and
Fig. 2 is a view looking toward the bottom of the spark plug assembly.
The preferred form of spark plug assembly in which the electrode is utilized is shown in Fig. 1. This assembly includes a main body it! in which a pair of axially aligned and spaced apart electrodes 11 and 12 are positioned. Electrode 11 is positioned in the center of either the base of the main body, as shown, or in the center of an insert which may be used in place of the base of the main body. A bore 13 is preferably formed in electrode 11, the bore serving to cause the pressure relations in the ignition chamber 15 during operation of an internal combustion engine to favor improved ignition conditions. Helical passages 14 are provided in the base of the main body or the insert for the passage of the combustible fuel to and from an ignition chamber 15 within the main body to an associated engine cylinder (not shown). The passage of fuel through these helical passages produces a swirling effect in the ignition chamber.
Mounted within the main body is an insulating body 16, of the type normally made of ceramic, containing electrode 12 and a rod 17 connecting the electrode to a suitable source of electrical energy (not shown). Hold down nut 18 is provided for properly positioning and holding the insulating body in place.
Electrode 12 includes a metal shell 19 of conductive material, which is also highly resistant to corrosion and a core 20 within said shell composed of a material through which heat is rapidly dissipated, preferably sodium. A plug 21 is provided to hold the sodium filling in the metal shell.
Although the electrode of the invention is shown as being applied to a particular spark plug assembly, it is to be understood that it may be utilized in any construction where a spark gap electrode can be utilized in order to minimize the pitting of the electrode.
It should be apparent that details of construction can be varied without departing from the spirit of the invention except as defined in the appended claims.
What is claimed is:
1. A spark gap electrode comprising a metal body having a cavity therein, and a pure sodium core in said cavity.
2.A spark plug assembly comprising a hollow body having a cylindrical internal space defining an ignition chamber, two axially aligned and spaced apart electrodes, one of said electrodes having a main metal body with a cavity therein and a pure sodium core in said cavity, and helical passage means connecting the cylindrical internal space to the exterior of the assembly.
References Cited in the file of this patent UNITED STATES PATENTS 2,127,513 Harper Aug. 23, 1938 FOREIGN PATENTS 297,975 Canada Mar. 4, 1930 Patent No. 2,871,388 January 27, 1959 Paul F. Adair n the printed specification appears i n and that the said Letters It is hereby certified that error correctio of the above numbered patent requiring Patent should read as corrected below.
Column 2, line 43, before "metal" insert main Signed and sealed this 19th day of May 1959.
KARL H. AXLINE ROBERT C. WATSON Commissioner of Patents Attesting Officer