WO2005013448A1

WO2005013448A1 - Spark plug

Info

Publication number: WO2005013448A1
Application number: PCT/EG2004/000030
Authority: WO
Inventors: Hosny Ibrahim Sabry
Original assignee: Hosny Ibrahim Sabry
Priority date: 2003-08-03
Filing date: 2004-08-03
Publication date: 2005-02-10
Also published as: WO2005013448B1; CN1864307A

Abstract

A spark plug for an internal combustion engine which utilizes an annular round ring surrounding the center electrode. The ring is either completely rounded or divided in two ring halves separated by a specific distance. In another embodiment the ring is divided into three equal parts including three equal voids. The rings are welded to the threated body of the plug via at least one rod. Preferably the center electrode is terminated by a metallic small ball of nickel alloys.

Description

Spark Plug

Technical Field:

Internal combustion engines (except diesel engines)

The previous art:

Spark plugs are being used in most interior combustion engines, excluding diesel ones, so as to provoke sparks of high potential igniting the mixture of fuel and air inside the combustion chamber. Figure (1):

1- Tenninal.

2- Anti-flashover

3- Cap.

4- Gas-tight.

5- Central electrode.

6- Attached gasket.

7- Axial tip.

8- Spark gap.

9- Earth electrode

10- Axial metallic electrode.

11- Insulating manifold of the plug core .

12- An assembly of sheath.

The Manufacture:

The design techniques and materials used vary from one manufacturer to another, but the following description is fairly representative. Plug bodies are made of high quality steel and are zinc plated to avoid corrosion. The spark plug consists of, as in figure (1) external metallic housing (3) inside which porcelain insulator mounted (11), having a metallic electrode of circuit (10) adjusted on the axis of the insulator. The external housing compromises the other metallic terminal of the circuit (9) being short joined with solder to the end of the tlireaded body and arcliing towards the axial tip, and the tlireaded portion on the external housing has to conform to internationally agreed standards and close tolerances and it is also of close durability enough to install the sparkplug into a threaded aperture in the head of engine cylinder. Ranges of plugs with various thread configurations are produced. The plug insulators are made of a fired aluininum oxide (ceramic material), which is highly resistant to thermal and mechanical stress, and chemical attacks. The electrodes are most commonly made from nickel alloys, but precious metals are sometimes used. Within the two electrodes, there is a gap distance (8) ranging between 0.5-1.016 mm (0.020-0.040) inches. Gas tight seals (4) are required between the center electrode and the insulator, and between the insulator and the plug body. These seals are formed from aluminum oxide powder which when compressed becomes a rigid mass fits the available space exactly. To keep pace with engine requirements new construction techniques and materials are constantly being evaluated.

Operation:

When the engine is raming, a pulse of electrical energy at very high voltage is delivered to the terminal of the plug (or plugs in the case of multi- cylinder engines, via the distributor) at the correct moment, these causes a spark to jump the gap between the center electrode (10) and the earth electrode (9) the latter being earthed to the cylinder block. This spark provides the energy needed to ignite the compressed fixel-air mixture in the cylinder.

Operating temperature:

For optimum performance, the temperature of the core nose at the firing end of a spark plug should neither drop below about 400 °c (752°f) at 30 mph (48km/h) cruising, nor exceed about 850°c (1562°f) at maximum speed and load. Below 400°c, deposits of carbon and oil are likely to accumulate on the core nose. Carbon being electrically conductive can provide a short circuit path for the high voltage pulse and so weaken or elmiiiiate the spark.

Core nose temperature of above 850°c can cause excessive electrode erosion and, possibly, uncontrolled ignition of the fuel-air mixture in advance of the timed spark. This condition (called pre-ignition) can cause serious engine damage. As engine designs (and therefore combustion chamber temperatures) vary, it is necessary to produce many types of spark plug to ensure that, as far as possible, plug operating temperatures can be kept within the optimum range in all applications.

Heat range:

The classification of plugs according to their relative ability to transfer heat from the tip of the core nose to the cooling system of an engine is termed the heat range. For the purpose of detenriining which grade of plug is best for specific engine, the manufacturers run tests using sparks plugs comprising thermocouples (sensitive elements to temperature) at the core nose tips; whilst, constantly monitoring the temperature of the different types at the integrative extent of the engine load and speed. The maintenance:

The spark plugs should be cleaned every 10000 Km via sand paper or spark plug cleaner so as to remove the accumulated deposits on the base of central electrode, followed by adjusting the gap distance between the two electrodes through the lateral electrode by slightly bending the ground electrode.

It is preferably to alter the plugs every 20000 Km averting the possible troubles and guarantee the high quality of activating the engine. Unless the new spark plugs are of the definite type according to engine guidelines, the insulating material will be destroyed. It is worth mentioning that the plug is rapidly consumed when its usage in the engine is under high temperature for the speed combustion of its terminals. Therefore, applying spark plugs of incorrect heat range drives occurrence of engine problems, as well as, causing cracks in the insulators of the plugs as a result of negligence on installing it or adjusting the gap between the plug's terminals.

The preceding inventions:

Spark plugs having three or four earth electrodes are recently available being more efficient than that of mono earthed electrode and having undoubtedly a prolong functional life.

The problem or deficiency of the previous art:

1- The electrodes of the traditional spark plug are to be cleaned for removing the hanging deposits every 10000 Km at most.

2- Upon removing the deposits, the gap distance between the two electrodes is to anew adjusted for not causing cracks in the plug insulators

3- Every 20000 Km, the plugs have to be replaced for ending its expiry period suffering from oxidation and corrosion of its electrodes.

The new in the invention:

The proposed alteration of the modified spark plug boils down in the following:

(1) Namely changing the Earthed electrode (while keeping the central electrode as it is): having the shape of rounded metal ring of 1.50 mm thickness and 2 mm width whether with frill or incomplete roundness, 3/4 or 2/3 annulus or two halves within which space of 2 - 2.5 mm at the interior surface of the ring or any other distance in consistence with the ring's interior diameter, whatever big or small it is, having the shape of a ring divided into three parts among wliich three equidistant voids or hemi-ring (as shown in chart No.6 figure (6) No 14) all of winch made of nickel alloys of 2 mm width and 1.5 mm thickness, and, its external diameter is not exceeding 8 mm welded with the end of the metallic housing via a rod, two, or tliree ones of nickel alloys of 2 mm width, and 1.5 mm thickness. The related ring is coaxial with the central electrode, where the axis of the central electrode is slightly higher than the ring plane (chart No. 2 fig 2 a No 14 &13 respectivly), provided that the gap distance between the two electrodes is like the existing gap in the common spark plugs. This modification is to increase the length of the interior contour of the ring fonning the ground electrode, thus, increasing the functional life of this modified plug comparing to the ordinary one. (2) Or changing the form of both electrodes:

As previously mentioned, the ground electrode takes the shape of full rounded ring or any shape of the forgoing proposed circular forms. However, the central electrode made also of nickel alloys is preferable:

(1) To be terminated with small metallic ball of nickel alloys having diameter of 3 mm and being coaxial with the ring center, (chart No.4, figure 2 C No.13)

(2) Or to be terminated with metallic disc of 1.5 mm thickness having diameter of 3mm, and also coaxial with the core center of the ring.

(3) Or increasing the thickness of the central electrode to be 3 mm instead of 2.2 mm, being coplanar and coaxial with die axis of the ground electrode (chart No.5, figure 2D No.13).

The preceding modifications are to increase the length of central electrode contour and the interior contour of the ring (ground electrode) while mamtaining the gap distance between the two electrodes in all cases as it is in the ordinary ones that is ranging between (.5- 1.016 mm) resulting in greatly increasing the functional life of the modified spark plugs with no need to adjust the distance gap as in the existing spark plugs through the ground electrode nor prior to usage nor after removing the accumulated deposits, since this distance is unchangeable. The fixed gap distance ought to be labeled on the plug body; accordingly, the buyer can select the right plug to be easily fitted with his own car engine.

The relevant design is characterized with the fact that the spark does always jump between the two electrodes in certain direction as in the traditional plugs, it rather emits in any direction of the central electrode to the corresponding point on the interior contour of the ring (the ground electrode).

Suppose, after a period of usage, an oxidation can occur for any two corresponding points between the two electrodes due to the deposits accumulated in a way that prevents the emitting of the spark between them, that does not mean; the spark stops jumping within two different points corresponding on the two electrodes, and of course, there is a plenty of these corresponding points. Consequently, there is no need to the spark plug unless the deposits accumulated on the whole points of the ring's interior contour (ground electrode) and the exterior contour of the central electrode, in tins way, the functional life of the modified spark plug will more multiplied than that of the ordinary one. Additionally, with the voids existing between the rings, the deposits are not likely to accumulate on their inner surfaces. Above and beyond, the multi-shapes of the rings (ground elecfrode) introduce spark plug s of different functional life with different costs to be available for the buyer to pick the proper price for him.

Detailed description:

The suggested modification for improving the performance of the traditional spark plug focuses on its electrodes as follows:

Firstly: replacing the ground electrode with another metallic ring with full or incomplete roundness (3/4 or 2/3) annulus, two halves of ring with

2-2 1/2 mm interior distances between them or any proper distance according to its internal diameter whether it is small or big, or having the shape of annulus divided into tliree equal parts with tliree equal proper gaps between them, or having the shape of half ring, all of winch are often made of nickel alloys (diagram no.6, figure 6 no.14) with width of

(2 mm) and thickness of (1 1/2 mm). The length of their diameters depends on that of the central electrode, which is usually (2 1/2) mm. In this case, the inner diameter of the ring will be from 3.5 to 4.532 mm and its outer one from 6.5 to 7.532 mm. This is to keep the gap between the two electrodes ranging between 0.5 to 1.016mm that welded with the end of the metal sheathing of the spark plug via one, two or tliree rods of nickel alloys. The width of each one is 2mm, 1 1/2 mm thickness and 4:6 mm length (diagram no.3, figure 2b no. 15) and (diagram no. 2, figure 2a no. 15,16 respectively) encircling the central electrode in which both of them are co-axial whether its terminal is located on the ring's level or few millimeter higher as shown in (diagram no.2, figure 2a no.13, 14).

Moreover, the ground electrode can only be modified with no change in the central electrode in order to increase the functional life of the modified spark plug's performance.

Secondly: conducting modifications on the central electrode made of nickel alloys through one of these steps :- a- it is terminated with small metallic ball of 3 mm diameter (diagram no.

4, figure 2c no. 13). b- it is terminated with a metallic disc of 1 1/2 thickness and 3mm diameter. c- or increasing its thickness in winch its diameter will be 3 mm instead of 2.2 mm or 2 1/2 mm (diagram no. 5, figure 2d no. 13). Moreover, the modification of the central electrode is accompanied with that of the ground electrode in the same time via replacing it with metallic ring or any of the previous suggested circular shapes. However, its interior diameter will be ranging from 4 to 5.032mm and the outer one from 7 to 8.032 mm, respectively.

That is for the purpose of keeping die distance of the used gap between die electrodes provided that the core center of the ring adjusted on that of tlie metallic ball, that of the disc, or that of the central electrode where its terminal being coplanar with the related ring.

The aim of this modification is to increase the length of the central electrode' s contour to increase the points that the spark of the earth electrode emitting.

If the modification includes the two electrodes, the functional life of the modified spark plug will increase more than that of namely modifying the earth electrode. Tins is to increase the length of the contour of the two corresponding electrodes, namely, the ground and central at the same time.

The method of performing the improved spark plug:

The spark jumps in any direction from any point on die contour of the central electrode to its corresponding point on the inner surface of die ring (ground electrode) however, it always has an accurate direction never changes in the traditional spark plug.

Suppose, that after a span of time, an oxidation is happened to any of the corresponding points between the two electrodes, and, deposits accumulated on them preventing the jumping of the spark between them. This will not prevent the spark from emitting between any other corresponding points between the two electrodes. Since, the corresponding pomts between die two electrodes are so many that it will take a long time before whole oxidation occurring compared to traditional spark plug.

Accordingly, the suggested modification guaranteed the efficiency of the performance and the functional life much longer than that of the traditional one. Added to this, the existed gaps between the different rings prevent die accumulation of deposits easily on the inner surface. Moreover, producing various shapes of rings (groimd electrodes) resulted in making die modified plug available with different working life and prices providing die purchaser with the opportunity to pick the proper one for him. Method of exploitation:

The modified spark plug does not require improving in the manufactured substance of die electrodes, or modifying the manufacturing machines of the spark plug. Its costs will be higher than d at of die traditional one due to the increase in the material used in the ground electrode only or in both electrodes. However, tiiis slight increase in price is compensated by advantages such as:

1- die lifetime of the modified spark plug is relatively longer than tiiat of the traditional one,

2- it surpasses the other traditional types simply because the performance of an individual plug is dispensing to that of several plugs.

3- saving money & time wasted in purchasing new spark plugs and install them periodically in the engines.

4-It does not need maintenance as in traditional one every 10000km. (maintenance here means removing deposits that are stuck in its electrodes). Besides, there is no need to adjust the gap distance between d e two electrodes after the cleaning process in each time, winch save time & effort.

According to all these merits, the modified spark plug will be out of competition and preferred to consumer.

Brief Description of the drawings:

1 -Diagram (1) figure (1) of a longitudinal section of a traditional spark plug having one short groimd metallic electrode (no.9) which is welded with one end of the threaded body of d e plug and bends towards its axial tip (die other central metallic electrode no.10).

2-Diagram (2) figure (2a) shows a longitudinal section of the modified spark plug in which the mentioned groimd electrode in diagram (1) is replaced with a rounded metallic ring (14) that completely surrounds the central electrode (13) as its terminal is being higher than the ring, so as, its center is precisely adjusted on the central electrode's axis. Moreover, d e ring is welded with die end of die threaded body via two metallic rods, (15,16).

3-Diagram (3) represents longitudinal section of the modified spark plug figure (2b).

What illustrated about diagram (2) is applied on diagram (3) as well. However, the difference is confined only on diat die ground electrode is welded with the spark plug by only one metallic rod (14).

4-Diagram (4) figure (2c) represents a longitudinal section of the modified spark plug in which the axial tip ends with a small metallic ball (13) which is surrounded with the ground electrode (14), having the shape of a circular metallic so that, the groimd electrode center is adjusted on the central electrode center (i.e. the ball's center).

5-Diagram (5) figure (2d) represents longitudinal section of the modified spark plug. The thickness of the axial electrode (13) is lager than that of the traditional spark plug. The ground electrode with its circular shape surrounds die axial electrode, in such a manner that its center is adjusted on die central axial electrode in winch its teπninal is co-planar with the spark plug.

6- Diagram (6) figure (6) represents all different circular shapes tiiat are suggested to die groimd electrode (14) which are full or incomplete roundness (3/4 or 2/3) annulus, two halves of ring, half ring, and annulus divided into three equal parts.

Claims

The first claim: A normal spark plug that includes two new modified electrodes instead of the ground and central ones.

The second claim: according to the first claim, the groimd electrode of die traditional spark plug is completely exchanged by another one, shaped as a complete or incomplete metallic rounded ring (3/4 ring or 2/3 ring) two halves ring interiorly separated by a distance ranging between 2-2 1/2 mm or any other appreciate distance, having the shape of a ring divided into three equal parts including tliree equal and convenient voids, or shaped as a half ring all the rings are often made of nickel alloys, having 2 mm of width and 1 1/2 mm of tiiickness. The rings are usually welded with the end of the tlireaded body of the plug via a rod, two,or tliree ones of nickel alloys of 2 imn width, and 1.5 imn tiiickness and 4-6 mm of height from the end of the tlireaded body of the plug, that completely encircles the central electrodes. Its diameter are different according to die central electrodes diameter tiiat usually ranges between 2.2-2.5 mm. To aim at keeping the gap distance between the electrodes as that of die traditional spark plug, which ranges between 0.5 - 1.016 imn.

The third claim: according to the first claim, the central electrode is modified too as follows:

- Its terminal terminated by a metallic small ball made of nickel alloys witii a diameter (3 mm).

- Its diameter is 3 imn instead of 2,2 imn or 2 1/2, so its tiiickness is changed.

- Its teπninal terminated by a metallic disk made of nickel alloys of 3 mm diameter and 1 1/2 mm of tiiickness.