Patent ID: 8915227

Claim:
A spark plug of an internal combustion engine comprising: a main body having a main thread formed on the lower outer side thereof by a predetermined length; an insulator mounted in a hollow portion of the main body while coating a terminal rod which is embedded in the central area of the main body with insulating material; a central electrode extending from lower end of a terminal rod embedded in the insulator to be exposed to the outside; a ground electrode formed on the lower inside of the main body to correspond to the central electrode; a primary combustion chamber forming shell having female thread formed on an inner surface of an opening to be screw-coupled with the main thread, male thread formed on the outer surface to fix a combustion chamber, and an ejection hole formed on the lower end; the primary combustion chamber formed between the main body and the primary combustion chamber forming shell to accommodate the central electrode and the ground electrode and having a volume of which is adjusted by a screw coupling length between the main body and the primary combustion chamber forming shell; and a heat exchange member which is disposed between the main body and the insulator to exchange heat caused by flame generated by ignition by the central electrode and the ground electrode and to block leak of volatile gas; wherein the ejection hole has a single main ejection hole formed at the central area of the lower end of the primary combustion chamber forming shell and at least two auxiliary ejection holes formed around the main ejection hole in the circumferential direction to be inclined laterally to form a vortex of the flame discharged from the primary combustion chamber.