GB2085521A

GB2085521A - Spark plugs

Info

Publication number: GB2085521A
Application number: GB8033494A
Authority: GB
Original assignee: FEASTER JAMES LOUIS
Current assignee: FEASTER JAMES LOUIS
Priority date: 1980-10-16
Filing date: 1980-10-16
Publication date: 1982-04-28
Also published as: GB2085521B

Abstract

A spark plug for an internal combustion engine includes a pair of electrodes 17 spaced alongside each other, and extending through an insulator 11 fitted in a metal casing 12 that is threaded, so as to be screwed into the engine, each electrode being intercepted by a solid- state H.V. time delay device 22, which may comprise a high voltage diode or a solid-state semi-conductor. The same, or different numbers of diodes may be connected in the electrodes. <IMAGE>

Description

SPECIFICATION Spark plug This invention relates generally to ignition devices, and more particularly, to internal combustion engine spark plugs. Still more particularly, it relates to spark plugs of dual ignition gap type.

Dual gap spark plugs have been known in the art. These plugs, however, were of simple design, providing elementary gaps for simultaneous nonindependent ignition. In this way, they provided greater reliability, in that, should one gap "foul", the other would provide ignition for continued combustion within the cylinder, although at some reduction in efficiency.

It is a principal object of the present invention to provide a spark plug for fitting in a single spark plug opening of an engine cylinder, but which is characterised by having a plurality of electrodes, instead of only one, thus providing a means of delivering two high voltage sparks independently of each other, for igniting the compressed fuel and air mixture within the engine cylinder; and each of the electrodes being intercepted by a solid-state H.V. time delay device, for delaying a spark ignition.

Another object is to provide a spark plug of the type described, which may utilise one high voltage ignition system, for producing a spark at both gaps of the plug, or it may be adapted for use with a dual high voltage ignition system.

Yet another object is to provide an improved dual internal electric spark plug, in which each of the time delay devices may be out of synchronization from each other, and may be timed for different intervals.

Still another object is to provide an improved dual internal electric spark plug, which is fired from two different ignition systems, and wherein they are out of synchronization, so that a firing from each is controlled in selective delay intervals.

Still another further object is to provide a spark plug of the type described, which will substantially increase volumetric efficiency of an internal combustion engine, while simultaneously decreasing air pollution from the engine exhaust.

Other objects are to provide an improved dual internal electric spark plug, which is simple in design, inexpensive to manufacture, rugged in construction, easy to use and efficient in operation.

According to the present invention there is provided an improved dual internal electric spark plug, comprising, in combination, an insulator, a casing around said insulator, means for attaching said casing for attachment to an engine cyclinder head, and a pair of electrodes through said insulator, one protruding end of said electrodes being designed for connection to electric wiring connectors, and opposite protruding ends comprising positive contacts respective to substantially L-shaped anvil negative contacts formed on said casing, and each of said electrodes being interrupted by solid-state H.V. time delay device.

While the invention will be described in connection with an example embodiment, it will be understood that it is not intended to limit the invention to such embodiment. On the contrary, it is intended to cover all alternatives, modifications assd equivalents as may be included within the scope of the invention as defined by the appended claims.

An embodiment is illustrated in the accompanying drawings, wherein Fig. 1 is an electrical diagram showing one design of diode combination in an electrical circuit of a dual spark plug, each electrode of the spark plug being intercepted by a time delay device comprised by the diodes; Figs. 2 to 6 are each an electrical diagram of different diode combinations in an electrical circuit of a dual spark plug, each electrode of the spark plug being intercepted by a time delay device comprised of the particular arrangement of the diodes; Fig. 7 is a side elevation view of a spark plug incorporating the present invention; Fig. 8 is a cross-sectional view thereof on a longitudinal axis, and on the same plane as Fig. 7; Fig. 9 is a bottom view thereof;; Fig. 10 is a cross-sectional view similar to Fig. 8, and showing a modified construction thereof, wherein the delay devices of the electrodes may be selectively varied, and Fig. 11 is a transverse cross-sectional view, taken on line Il-Il of Fig. 10.

In the following description, similar features have been given similar reference numerals.

Referring now to the drawings in greater detail, and more particularly to Figs. 1, 7, 8 and 9 at this time, the reference numeral 10 represents an improved dual internal electric spark plug, according to the present invention, wherein there is provided an insulator 11, which may be moulded of ceramic material, and which is made inside a steel casing 12, having a barrel portion 1 3 at one end thereof, made with an external screw thread 14, for screwing into an engine cylinder head. An opposite end 1 5 of the casing is hexagonal in shape, so as to be turned by a wrench. An intermediate portion 1 6 may be knurled for turning by a hand.

Two electrodes 17, in parallel, spaced-apart relation to each other, extend through the insulator. The upper protruding ends 1 8 thereof are shaped for electric wire connectors to snap-fit therearound, while the lower protruding ends comprise positive contacts 19, spaced from Lshaped anvils formed on the casing barrel, so as to comprise negative contacts 20. A space between each pair of contacts 1 9 and 20 comprises a gap 21, across which a spark can jump. A different number of such diodes may be provided in the delay device of each of the electrodes, so that each electrode is differently delayed in firing a spark.

Alternatively, it may comprise a solid-state semi-conductor. While it is neither a resistor nor a conductor, it does have the characteristics of both of them together.

A protruding barrier 24, on an end of the insulator, extends between the sets of contacts, so as to prevent any possibility of a spark from one set effecting the other set.

It is to be noted, as shown in Figs. 1 to 6, that various combinations of diodes may be used in the electrical circuit of the delay devices 22. The various combinations that are possible to make are not limited to the examples illustrated, but may comprise others not shown, as well. It is through the various combinations that the delay in the ignition is achieved. Heat and high voltage can both be tolerated on the manufacture of a diode for this purpose, and it is also not affected by vibration. The individual external ignition system (or systems) is protected from flash back, the inter-electrode shield at the tip of the plug not being required, although it would aid in confining the ignition spark to its respective anvil.

An important feature of the present invention is that the two closely-timed ignition sparks will increase the efficiency of the burn, over that of two simultaneous ignition sparks for the same volume of fuel mixture.

Figs. 1 to 6 show that the terminals to the distributor, and/or ignition system (or systems) may be made either positive (+) or negative (-).

All diodes are of high voltage type, with special physical and electrical design considerations for insertion into the respective cavities provided for the insulator at the time of manufacture.

A fixed pre-determined high voltage time delay can thus be achieved. The unidirectional diode design, shown in Figs. 1 to 6, prevents flash back across the electrodes. A lean burn, for greater combustion efficiency, is attained.

Referring now to Figs. 10 and 1 a modified design of improved dual internal electric spark plug 25, is the same as plug 10, except that it additionally includes the feature of the delay device for each electrode being selectiveiy adjustable. Thus, as shown, four solid-state H.V.

time delay devices 22, of different delay values, are carried in a rotatable barrel 26, made of insulator material, and which is rotatably mounted inside an opening 27, formed in the insulator 11 by means of spring-biased pivot pins 28, so that either of the delay devices are aligned between opposite ends of the electrodes. The delay devices may be spring biases, as shown, in order to insure electrical contacts therebetween and the electrodes.

While various changes may be made in the detail construction, it is understood that such changes will be within the scope of the present invention, as is defined by the appended claims.

Claims

CLAIMS 1. An improved dual internal electric spark plug, comprising, in combination, an insulator, a casing around said insulator, means for attaching said casing for attachment to an engine cylinder head, and a pair of electrodes through said insulator, one protruding end of said electrodes being designed for connection to electric wiring connectors, and opposite protruding ends comprising positive contacts respective to substantially L-shaped anvil negative contacts formed on said casing, and each of said electrodes being interrupted by solid-state H.V. time delay device. 2. The combination as set forth in claim 1, wherein said time delay devices comprise a plurality thereof, selectively aligned between opposite ends of said electrodes for preferred use. 3. The combination as set forth in claim 2, wherein said time delay devices are of different delay intervals. 4. The combination as set forth in claim 3, wherein said delay devices comprise a plurality of diodes arranged for either a negative or a positive system. 5. The combination as set forth in claim 4, wherein said diodes are arranged alike, so as to prevent a flash back across said electrodes. 6. An improved dual internal electric spark plug as claimed in claim 1, substantially as described with reference to and as illustrated by the accompanying drawings. New claims or amendments to claims filed on 24/9/81 Superseded claims 1 to 6. New or amended claims:

1. An improved dual internal electric spark plug, comprising, in combination, an insulator, a casing around said insulator, means for attaching said casing for attachment to an engine cylinder head, and a pair of electrodes through said insulator, one protruding end of each said electrode being designed for connection to an electric wiring connector, and the opposite protruding end comprising a positive contact positioned in proximity to a corresponding substantially L-shaped anvil negative contact formed on said casing, and each of said electrodes being interrupted by a corresponding solid state H.V.

time delay device.

2. A dual electric spark plug, comprising a cylindrical metal casing with a threaded barrel for insertion into an opening of an internal combustion engine, an integral cap nut, a pair of spaced apart electrodes secured within an insulator, secured in said cylindrical metal casing, a pair of solid state, time-delay devices secured in said insulator for time-delay firing of the spark plug between its electrode tips, and a pair of ground anvils, and shield means extending from said insulator, between said electrode tips and said ground anvils.

3. The combination according to claim 2, wherein said insulator is fixedly secured in said cylindrical metal casing, and said electrodes are fixedly secured in said insulator, and said solid state time-delay devices are, one each, connected electrically in series with said electrodes, and each electrode is fixedly secured in said insulator, above the cap nut of said cylindrical metal casing for maximum cooling thereof.

4. The combination according to claim 3, wherein said insulator at the top of the spark plug is terminated by a pair of projections which are spaced apart and integral of said insulator, and each of said pair of projections, houses the upper portion of one of said electrodes, and the bottom portion of said insulator includes said shield means, which comprises an extending and integral portion of said insulator, which is disposed between said electrode tips and said pair of ground anvils at the lower end of the spark plug.

5. A dual internal electric spark plug, comprising, in combination, a cylindrical, elongated insulator, a metal casing around a portion of said insulator, one end of said casing forming a threaded barrel for securement in a threaded opening of an internal combustion engine, and a pair of parallel, spaced apart electrodes extending axially through said insulator, said end of sid casing having a pair of "L" shaped anvils projecting therefrom, a tip of each of said electrodes projecting from a first end of said insulator to a point proximate a corresponding one of said anvils whereby to form an axially extending spark gap between said tip and said anvil, a flat shield formed across a center of said insulator first end and projecting axially between each pair of said anvils and tips, so as to separate said spark gaps from each other, said shield extending a distance that is larger than a length of said gaps between said anvils and said tips; opposite ends of each electrodes projecting from an opposite second end of said insulator being shaped for electrical connections, and a longitudinally intermediate portion of each of said electrodes having a solid state, time-delay device inserted therein.

6. The combination as set forth in claim 5 wherein said solid state, time-delay devices of said two electrodes are the same in terms of delay.

7. The combination as set forth in claim 5 wherein said solid state, time-delay devices of said two electrodes are not the same in terms of delay.

8. A dual electric spark plug, comprising a cylindrical metal casing with a threaded barrel for insertion into an opening of an internal combustion engine, an integral cap nut, a pair of spaced apart electrodes secured within an insulator, secured in said cylindrial metal casing, a pair of solid state, time-delay devices secured in said insulator for time-delay firing of the spark plug between its electrode tips, and a pair of ground anvils, and shield means extending from said insulator, between said electrode tips and said ground anvils; and wherein said time-delay devices are both diodes or both semiconductors.

9. The combination according to claim 8, wherein said insulator is fixedly secured in said cylindrical metal casing, and said electrodes are fixedly secured in said insulator, and said solid state time-delay devices are, one each, connected electrically in series with said electrodes, and each electrode is fixedly secured in said insulator, above the cap nut of said cylindrical metal casing for maximum cooling thereof.

10. The combination according to claim 9, wherein said insulator at the top of the spark plug is terminated by a pair of projections which are spaced apart and integral of said insulator, and each of said pair of projections, houses the upper portion of one of said electrodes, and the bottom portion of said insulator includes said shield means, which comprises an extending and integral portion of said insulator, which is disposed between said electrode tips and said pair of ground anvils at the lower end of the spark plug.

11. The spark plug of claim 8 wherein each said time-delay device comprises at least one diode.

12. A dual internal electric spark plug, comprising, in combination, a cylindrical, elongated insulator, a metal casing around a portion of said insulator, one end of said casing forming a threaded barrel for securement in a threaded opening of an internal combustion engine, and a pair of parallel, spaced apart electrodes extending axially through said insulator, said end of said casing having a pair of "L" shaped anvils projecting therefrom, a tip of each of said electrodes projecting from a first end of said insulator and being axially spaced from each of said anvils so as to form an axially extending spark gap therebetween, a flat shield formed across a center of said insulator first end and projecting axially between each pair of said anvils and tips, so as to separate said spark gaps from each other, said shield extending a distance that is larger than a length of said gaps between said anvils and said tips; opposite ends of each electrodes projecting from an opposite second end of said insulator being shaped for electrical connections, and a longitudinally intermediate portion of each of said electrodes having a solid state, time-delay device inserted therein, said time-delay devices being both diodes or both semiconductors.

13. The combination as set forth in claim 12 wherein said solid state, time-delay devices of said two electrodes are the same in terms of delay.

14. The combination as set forth in claim 12 wherein said solid state, time-delay devices of said two electrodes are not the same in terms of delay.

1 5. The spark plug of claim 12, wherein each said time-delay device comprises at least one diode.

16. The combination as set forth in claim 1, wherein each said time-delay device comprises a plurality thereof, selectively aligned between opposite ends of said electrodes.

1 7. The combination as set forth in claim 2, wherein said time-delay devices are of different delay intervals.

1 8. The combination as set forth in claim 3, wherein said delay devices comprise a plurality of diodes arranged for either a negative or a positive system.

1 9. The combination as set forth in claim 4, wherein said diodes are arranged alike, so as to prevent a flash back across said electrodes.

20. The spark plug of claims 11 and 1 5 wherein each said time-delay device comprises a plurality of diodes.

21. The spark plug of claims 11 and 1 5 wherein each said diode is arranged to conduct in the same direction.

22. The spark plug of claims 11 and 15 wherein each said time-delay device comprises a plurality of diodes and each said diode is arranged to conduct in the same direction.

23. An improved dual internal electric spark plug, comprising, in combination, an insulator, a casing around said insulator, means for attaching said casing to an engine cylinder head, and a pair of electrodes through said insulator, one protruding end of said electrodes being designed for connection to electric wiring connectors, and opposite protruding ends comprising positive contacts respective to substantially "L"-shaped anvil negative contacts formed on said casing, and each of said electrodes being interrupted by solid state H.V. time-delay devices; a plurality of said time-delay devices being circularly arranged and extending axially in a rotatable barrel inside said insulator, so that said time delay devices are selectively aligned between adjacent ends of each said electrode for preferred use.