US3706897A - Spark plugs - Google Patents

Abstract

A sparkplug for use in internal combustion engines having a disk shaped electrode mounted at an angle to the uniplanar base of the plug which serves as the other electrode. The fact that the disk electrode substantially overlies the other electrode and is mounted at an angle causes the disk to be cleaned by a sweeping action of gaseous movement during the explosion and further permits the generation of a variable spark which is directly related to the voltage and thus the speed of the internal combustion engine.

Description

United states Patent Shepardson [451 Dec. 19, 1972 [s41 SPARK PLUGS [72] Inventor: Harvey K. Shepardson, P.O. Box

161 North Filliwaup, Jefferson County, Wash. 98555 [22] Filed: Jan. 19, 1971 [21] Appl. No.: 107,626

[52] US. Cl ..3l3/141, 313/142 [51] Int. Cl ..l-I01t 13/20 [58] Field of Search ..313/14l, 142

[56] References Cited UNITED STATES PATENTS 1,492,338 4/1924 Ricke "313/141 X 2,069,320 2/1937 McKone ..313/l42 2,795,723 6/1957 Townsend, Sr ..313/l41 2,845,566 7/1958 Regar ..'....313/141 Primary Examiner-Nathan Kaufman AttorneySeed, Berry, Dowrey & Cross [57] ABSTRACT A sparkplug for use in internal combustion engines having a disk shaped electrode mounted at an angle to the uniplana'r base of the plug which serves as the other electrode. The fact that the disk electrode substantially overlies the other electrode and is mounted at an angle causes the disk to be cleaned by a sweeping action of gaseous movement during the explosion and further permits the generation of a variable spark which is directly related to the voltage and thus the speed of the internal combustion engine.

3 Claims, 3 l 3rawing Figures 1 SPARK PLUGS BACKGROUND OF THE INVENTION This invention relates generally to improvements in sparkplugs for internal combustion engines or similar usesand more particularly relates to improvements in the igniter electrodes of such plugs.

As is commonly known, the compressed combustible fuel-air mixture in the cylinder of an engine is fired by the instantaneous impression of a high electrical potential across'the electrodes of the sparkplug. This potential causes a spark to jump the gap between the electrodes and thus ignite the mixture. The usual sparkplug has a body made up of a metal shell, threaded to screw into the cylinder head, and an insulator axially through the center of which connection is made to a center electrode from the ignition system. The other side of the circuit is through ground or through the engine from the metal shell of the plug from the latter of which an outward or second electrode normally projects into proximity with the central electrode. Obviously, the electrodes and the inner portion of the plug itself are exposed to the gases in the combustion chamber so that the spark as it jumps between electrodes will be exposed to the fuel-air mixture for igniting the same. The gap between the electrodes must be properly adjusted to assure a reliable spark, this being an operation commonly called gapping.

Newly installed plugs, if the engine is in good condition, operate effectively until sufficient wear occurs within the engine so that lubricant enters the combustion chamber and burns forming a carbonaceous deposit upon the insulator. Initially the insulator, of course, has a very high electrical resistance but as the insulator becomes fouled by the comparatively electrically conductive deposit of carbon formed upon it, its resistance is lowered and ignition becomes faulty, particularly when the engine is idling. The condition of the insulator also has a bearing upon the length or spacing of the gap between the electrodes, and to prolong the useful life of the plug after its insulator resistance is lowered it is necessary to reduce the gap between electrodes. In presently used plugs this has a tendency to further shield the spark and make for poor ignition. At all times of course the insulator resistance must exceed the spark gap resistance or there will be no spark.

Attempts have been made to alleviate the above noted problems with sparkplugs and examples of the prior art attempts are noted in the patent to Hill, U.S. Pat. No. 1,416,557, granted May 16, 1922 wherein he uses a pair of rotatable disks mounted upon a bifurcated central electrode and depends upon the rotation of the disk to continuously present a clean surface for spark as well as a more constant gap. Another attempt at solving some of the problems is depicted in U.S. Pat.

attempt to alleviate the problems is shown in U.S. Pat.- No. 2,069,330 granted to Me Kone on'Feb. 2, .1937 wherein the electrode wires present convergent surfaces defining a spark gap of varyingwidth tocompensate for varying intensity of the spark atIdifferent engine speeds. Another attempt to alleviate the problems is taught by U.S. Pat. No. 2,795,723 granted to Townsend on June 11, 1957 wherein the outer electrode angles toward the face of the second electr'ode and has a tapered front surface such that the spark must form at the extreme outer edge. The most recent attempt at improving the sparkplug isshown'by the patent to Rigar. given Ser. No. 284,566 on July 29;

1958 wherein the electrodeis at an angle to the central electrode such that the plug will satisfy demand for a large variety of gap settings. 7

With the above noted problemsand attempts at solutions in mind it is an object of the present invention to provide a sparkplug wherein the distance between the central electrode and the outside electrode variessuch that the spark will differ depending upon the voltage thus assuring the most efficient burning of the fuel.

It is another object of the present invention to pro-,

vide a central electrode which .is in the form of adiskficient firing. I p

No. 1,495,499 to Stanislawski granted May 27, 1924 run a at an angle alpha (a) to the coplanar lower surface 10 BRIEF DESCRIPTION OF THE DRAWINGS DETAILED DESCRIPTION OF THE DRAWINGS 1 As can be seen in the .Figures the sparkplugincludes a central electrode 2 which extends entirely throughthe main body portion and out the oppositeend as thus seen in FIG. 2. Immediately surrounding the central. electrode 2 is an insulator 4 which substantially shields the electrode 2 throughout its entire length. Coaxial with the central electrode 2 and the insulator 4 is an: outer shell 6 which is made of a conductivematerial' and has a threaded lower portion 8 terminating'in a planar surface 10 as well as a hexagonally-shaped surface 12 for cooperation with the wrench for inserting; and removing the plug from the engine block. Theshelh 6 is adapted to serve as the second electrode and is-in' conductive contact with the engine block and thusserves as the ground. 1

As best seen in FIG. 2 the central electrode 2 terminates at lower end in a disk 14 which is mounted as of the shell 6. Asthus seen in FIG. 2 the central electrode 2 protrudes past the bottom rim or planar surface 10 and the plate or disk'14 is approximately the same size as the planar surface 10.

l060ll (H99 It is to be understood that the spark gap may be 7 changed to suit individual engines and the important concept is the fact that an angle is maintained. The preferred distance of the plate 14 from the surface 10 is 0.035 inches on one side and 0.070 inches on the other.

The angle of the disk or plate 14 with respect to the surface 10 causes asweeping action of the explosions which tends to clean the. areaof carbon and maintain the central electrode in functional condition for a greater length of time. Another advantage of the central electrode terminating in an angularly placed disk is that the spark is broad and fan shaped, capable of igniting a far greater area in a given time sequence. The greater the voltage that is applied to the central elec-. trode 2 the wider the spark as it has enough energy to jump across a large gap and thus encompass a larger part of the outer periphery of the disk 14.

Yet another advantage of the angularity of the disk 14 with respect to the surface 10 is that the spark which occurs during the lowest voltage is adjacent the combustion chamber wall where a relatively heavy concentration of fuel is located in a thin fuel-air mixture. Yet another advantage of the hereinabove described invention is the fact that the spark which is variable with In summary it is to be noted that the fact that the disk which terminates the'central electrode being placed at an angle to the surface of the bottom of the shell causes a sweeping action during explosion which reduces the carbon deposit and further allows the variable spark which is adjustable to accommodate the relative fuel 4 mixture as well as the relative speed of the engine turnover. The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows:

l. A sparkplug for use in internal combustion engines having an ignition system comprising; v

a shell having a threaded lower portion terminating in a coplanar surface adapted to be engaged with a bore having complementary threads in the block an elongated insulator coaxial with the shell andextending substantially through the interior of said shell and outwardlythereof at one end,

electrode means coaxial with the shell and extending through the insulator, the end of the electrode adjacent the outwardly extending end of the insulator adapted to be interconnected to the ignition system of the engine, the other end of the electrode terminating in a flat disk having its center located upon the axis of the shell and-extending outwardly to a position partially overlying the bottom of said shell and positioned at anangle to the planar surface of the shell whereby the spark width will vary in accord with the voltage supplied.

2. A sparkplug as in claim 1 wherein the disk is at an angle to the axis of the shell and the planar surface is normal to the axis of the shell.

3. A sparkplug as in claim 1 wherein the distance between the disk and the planar surface of the shell is 0.035 inches at the closest point and and 0.070 inches at the furthest point.

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Claims (3)

1. A sparkplug for use in internal combustion engines having an ignition system comprising; a shell having a threaded lower portion terminating in a coplanar surface adapted to be engaged with a bore having complementary threads in the block an elongated insulator coaxial with the shell and extending substantially through the interior of said shell and outwardly thereof at one end, electrode means coaxial with the shell and extending through the insulator, the end of the electrode adjacent the outwardly extending end of the insulator adapted to be interconnected to the ignition system of the engine, the other end of the electrode terminating in a flat disk having its center located upon the axis of the shell and extending outwardly to a position partially overlying the bottom of said shell and positioned at an angle to the planar surface of the shell whereby the spark width will vary in accord with the voltage supplied.

2. A sparkplug as in claim 1 wherein the disk is at an angle to the axis of the shell and the planar surface is normal to the axis of the shell.

3. A sparkplug as in claim 1 wherein the distance between the disk and the planar surface of the shell is 0.035 inches at the closest point and and 0.070 inches at the furthest point.

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