Claims:We Claim:
1. A spark plug (200) for an engine, said spark plug comprising :
a metal shell (202) comprising threads (204), said metal shell (202) adapted to be fitted onto said engine; characterized in that:
said metal shell (202) adapted accommodate an adapter 204; said adapter 204 comprising varying thread size.

2. The spark plug of claim 1, wherein said adapter is one of metallic adapter.

, Description:Complete Specification:

The following specification describes and ascertains the nature of this invention and the manner in which it is to be performed.
Field of the invention
[0001]This invention relates to the field of spark plug.

Background of the invention
[0002]A spark plug is used in a gasoline, CNG or LPG engine for enabling combustion of air and fuel mixture in the engine cylinder. The spark plug includes a central electrode, an insulating member which holds the central electrode in an axial hole, a metal shell which surrounds the periphery of the insulating member to hold the insulating member, and a ground electrode which is joined to the metal shell at a proximal end portion which forms a spark gap at a distal end portion with the central electrode. The fuel mixture is ignited by a spark discharge occurring in the spark gap.

[0003]The thread size of metal shell varies based on applications for example, for two Wheelers the thread size is M10 x 1.0mm, for passenger cars the thread size is M12 x 1.25mm, for 3 wheelers & bus categories the thread size is M14 x 1.25mm, M18 x 1.5mm used in Stationary Engines. The size being decided by engine manufacturer based on multiple parameters like cooling (fins) of engine, valve positioning (inlet and exhaust valve), cooling jacket size, exhaust temperatures and amount heat generated due to combustion. There is a need to ensure that spark plugs are used for various application irrespective of the dimensions of the spark plug.

Brief description of the accompanying drawing
[0004] Different modes of the invention are disclosed in detail in the description and illustrated in the accompanying drawing:

[0005] FIG. 1 illustrates a spark plug; and

[0006] FIG. 2 illustrates a spark plug with an adapter.

Detailed description of the embodiments
[0007] FIG. 1 illustrates a spark plug. The spark plug 100 disclosed herein is used for enabling combustion of air and fuel mixture in the internal combustion engine. The spark plug 100 is adapted to be located onto the head of the engine (not shown) and comprises at least an electrode 102 that is housed within an insulator 104. The electrode 102 in the spark plug 100 is used for generating a spark that ignites the air and fuel mixture. The electrode 102 is housed within the insulator 104. The spark plug comprises a threaded metal shell 202 that is adapted to be fitted onto the engine. The spark plug is used to ensure combustion of air and fuel mixture within the cylinder of the engine (not shown)

[0008] FIG. 2 illustrates a spark plug with an adapter. The spark plug comprises a metal shell comprising a thread, the metal shell adapted to be fitted onto the engine, the spark plug is characterized in that, the metal shell is adapted to adapted to accommodate an adapter 204, the adapter 204 comprises varying thread size, example: where the spark plug with M10x 1mm mounted with the adaptor of M12 x 1.25mm thread fitted on the engine. The thread length of the application can vary from 9.5mm to 26.5mm as per. The seating can be Flat or conical as per application requirement. The adapter 204 may be a metallic adapter.

[0009]The function of the adapter 204 is to ensure that the spark plug is used interchangeably. In order to achieve the above mentioned objective, the spark plug may comprise, for example, thread size of M10, this thread size remains constant and the thread size of the adapter is varied based on the different application. Hence by using different size of the adapter 204, the spark plug may be mounted onto engines of different spark plug mounting specification.

[0010]By using the above mentioned adapter 204 it is now possible to use the spark plug irrespective of the spark plug mounting specification or capacity of the engine and the power requirements.

[0011] ‘Adapted’ or ‘arranged’, in the context of the instant disclosure, refers to the technical capability or the technical capacity of a component, in relation to which the term ‘adapted’ or ‘arranged’ is used, to carry out or executed a specified action or actions, upon the requirement of the specified action or actions to be carried out or executed. Moreover, the usage of the term ‘adapted’ or ‘arranged’ here, is in reference with the normal technical capability or technical capacity of the component, imparted by the design or the structure or the composition of the component, and not in reference with any special or extraneous capability or capacity, beyond the scope of the normal technical capability or technical capacity. Therefore there is a need to address this problem.

[0012]It should be understood that embodiments explained in the description above are only illustrative and do not limit the scope of this invention in terms of the type of spark plug used. Many such embodiments and other modifications and changes in the embodiment explained in the description are envisaged. The scope of the invention is only limited by the scope of the claims.