GB2094883A

GB2094883A - Sparking plug

Info

Publication number: GB2094883A
Application number: GB8107809A
Authority: GB
Original assignee: Individual
Current assignee: Individual
Priority date: 1981-03-12
Filing date: 1981-03-12
Publication date: 1982-09-22

Abstract

A sparking plug for an internal combustion engine includes an outer electrode 3 and a central electrode 4, and located between the electrodes 3 and 4 is an intermediate electrode 7 which is isolated from the electrodes 3 and 4. In use of the sparking plug a double discharge will thus take place, a first discharge from the central electrode 4 to the intermediate electrode 7, and a second discharge from the electrode 7 to the external earth electrode 3. <IMAGE>

Description

SPECIFICATION Sparking plug The present invention relates to a sparking plug for an internal combustion engine.

It is well known that one of the problems affecting internal combustion engines is caused by the difficulties involved in obtaining a quick and perfect combustion of the fuel/air mixture flowing to the combustion chamber or chambers.

An imperfect or too slow combustion, in fact, results in a greater fuel consumption, a lower efficiency of the engine and a considerable air pollution.

According to the present invention there is provided a sparking plug, comprising a hollow earth electrode and a central electrode located within the hollow electrode, and in the space between said electrodes, at least one element of electrical conductive material forming an intermediate electrode isolated from the other electrodes, said intermediate electrode surrounding the central electrode.

The sparking plug of the present invention is capable of effecting a multiple discharge on a broad surface, improving thus the ignition of the mixture and, as a consequence thereof, the motor efficiency.

The sparking plug according to the present invention includes an element made of electrically conductive material, hereinafter called the "intermediate electrode", placed between the two normal electrodes, preferably around the middle one and electrically insulated from it.

This intermediate electrode enables the spark to spread over a broad surface, which ensures a better working of the engine.

Two embodiments of the invention will now be described, by way of non-limiting examples, with reference to the accompanying drawings, in which: Figure 1 is a partially sectioned view of one embodiment of a sparking plug according to the present invention, Figure 2 is a view from above of the sparking plug according to Figure 1, and Figure 3 is a view from above of another embodiment of a sparking plug according to the invention.

The sparking plug according to the invention consists essentially of a hollow body 1 which constitutes an outer electrode of the sparking plug, and to which are secured the other parts making up the sparking plug itself, as well as of a unit of two or more electrodes, preferably on the inside, indicated generally by reference 2 (Figure 1).

The body 1 is hollow and has an end 3 externally screw-threaded for mounting the sparking plug on the cylinder head of the engine.

The electrode unit 2 comprises a central electrode 4 secured inside the body 1 by means of a support 5 formed of electrical insulating material.

The electrode 4 has an outer end 6 outwardly protruding for connection to the ignition circuit of the engine.

Fixed to the end of the insulating support 5 is a conducting element 7, preferably annular, positioned adjacent the electrode 4 but insulated from it.

The conducting element 7 (or intermediate electrode), lies between the electrodes 1 and 4, insulated with respect to them and at a certain distance from each of them so that a spark may occur whenever a high voltage such as the one coming from the ignition circuit of the engine is applied.

In this way the intermediate electrode 7 brings about two sparks, the first occurring between the electrodes 4 and 7, and the second one occurring between the electrodes 7 and 1, the electrode 7 acting as a bridge or link through the dielectric medium.

Furthermore, the sparks thus obtained are not located in a single point as it is the case in conventional sparking plugs, but they spread along relatively broader annular surfaces, limited by electrodes 4, 7 and 1.

This results in obtaining a faster and more perfect combustion of the fuel/air mixture, and a more reliable operation of the engine. From tests carried out on vehicles provided respectively with two-cylinder engines of 500 cc and with fourcylinder engines of 1 300 cc, the fuel consumption rate was found in both cases to be more than 20% lower when operating with sparking plugs according to the present invention compared with operation under the same condition but using plugs of the conventional kind.

On the other hand, the sparking plugs according to the invention have made it possible to obtain, in the same engines and with the same fuel consumption, an increase in the number of revolutions of about 500 r.p.m.

Figure 3 shows another embodiment of a sparking plug according to the invention wherein the central electrode consists of a number of separated discharge points 8.

In this case, to keep the central and the intermediate electrodes always at an equal distance, the inner part of the intermediate electrode is shaped as to have a series of lobes 9 which extend into the spaces between the discharge points 8.

The intermediate electrodes may be obviously more than one, and have different shapes than those herein described.

1. A sparking plug, comprising a hollow earth electrode and a central electrode located within the hollow electrode, and in the space between said electrodes, at least one element of electrical conductive material forming an intermediate electrode isolated from the other electrodes, said intermediate electrode surrounding the central electrode.

2. A sparking plug as claimed in claim 1, in

**WARNING** end of DESC field may overlap start of CLMS **.

Claims

**WARNING** start of CLMS field may overlap end of DESC **. SPECIFICATION Sparking plug The present invention relates to a sparking plug for an internal combustion engine. It is well known that one of the problems affecting internal combustion engines is caused by the difficulties involved in obtaining a quick and perfect combustion of the fuel/air mixture flowing to the combustion chamber or chambers. An imperfect or too slow combustion, in fact, results in a greater fuel consumption, a lower efficiency of the engine and a considerable air pollution. According to the present invention there is provided a sparking plug, comprising a hollow earth electrode and a central electrode located within the hollow electrode, and in the space between said electrodes, at least one element of electrical conductive material forming an intermediate electrode isolated from the other electrodes, said intermediate electrode surrounding the central electrode. The sparking plug of the present invention is capable of effecting a multiple discharge on a broad surface, improving thus the ignition of the mixture and, as a consequence thereof, the motor efficiency. The sparking plug according to the present invention includes an element made of electrically conductive material, hereinafter called the "intermediate electrode", placed between the two normal electrodes, preferably around the middle one and electrically insulated from it. This intermediate electrode enables the spark to spread over a broad surface, which ensures a better working of the engine. Two embodiments of the invention will now be described, by way of non-limiting examples, with reference to the accompanying drawings, in which: Figure 1 is a partially sectioned view of one embodiment of a sparking plug according to the present invention, Figure 2 is a view from above of the sparking plug according to Figure 1, and Figure 3 is a view from above of another embodiment of a sparking plug according to the invention. The sparking plug according to the invention consists essentially of a hollow body 1 which constitutes an outer electrode of the sparking plug, and to which are secured the other parts making up the sparking plug itself, as well as of a unit of two or more electrodes, preferably on the inside, indicated generally by reference 2 (Figure 1). The body 1 is hollow and has an end 3 externally screw-threaded for mounting the sparking plug on the cylinder head of the engine. The electrode unit 2 comprises a central electrode 4 secured inside the body 1 by means of a support 5 formed of electrical insulating material. The electrode 4 has an outer end 6 outwardly protruding for connection to the ignition circuit of the engine. Fixed to the end of the insulating support 5 is a conducting element 7, preferably annular, positioned adjacent the electrode 4 but insulated from it. The conducting element 7 (or intermediate electrode), lies between the electrodes 1 and 4, insulated with respect to them and at a certain distance from each of them so that a spark may occur whenever a high voltage such as the one coming from the ignition circuit of the engine is applied. In this way the intermediate electrode 7 brings about two sparks, the first occurring between the electrodes 4 and 7, and the second one occurring between the electrodes 7 and 1, the electrode 7 acting as a bridge or link through the dielectric medium. Furthermore, the sparks thus obtained are not located in a single point as it is the case in conventional sparking plugs, but they spread along relatively broader annular surfaces, limited by electrodes 4, 7 and 1. This results in obtaining a faster and more perfect combustion of the fuel/air mixture, and a more reliable operation of the engine. From tests carried out on vehicles provided respectively with two-cylinder engines of 500 cc and with fourcylinder engines of 1 300 cc, the fuel consumption rate was found in both cases to be more than 20% lower when operating with sparking plugs according to the present invention compared with operation under the same condition but using plugs of the conventional kind. On the other hand, the sparking plugs according to the invention have made it possible to obtain, in the same engines and with the same fuel consumption, an increase in the number of revolutions of about 500 r.p.m. Figure 3 shows another embodiment of a sparking plug according to the invention wherein the central electrode consists of a number of separated discharge points 8. In this case, to keep the central and the intermediate electrodes always at an equal distance, the inner part of the intermediate electrode is shaped as to have a series of lobes 9 which extend into the spaces between the discharge points 8. The intermediate electrodes may be obviously more than one, and have different shapes than those herein described. CLAIMS

2. A sparking plug as claimed in claim 1, in which the central electrode consists of a number of separated discharge points, and the intermediate electrode is shaped so as to have a number of lobes which extend into the spaces between the discharge points, so that the surface of the intermediate electrode is always at a constant distance from the central electrode.

3. A sparking plug as claimed in claim 1 or claim 2, in which there are provided a plurality of intermediate electrodes.

4. A sparking plug substantially as hereinbefore described with reference to and as illustrated in Figures 1 and 2 or Figure 3 of the accompanying drawings.