Ignition plugs for internal combustion engine

An ignition plug for an internal combustion engine, the ignition plug comprising:

• a hollow main cell;
• a central electrode extending downward at a central portion of the main cell;
• a pair of ground electrodes disposed adjacent to a tip of the central electrode and having an arc form;
• and
• a pre-combustion chamber cell coupled to the main cell to cover the pair of ground electrodes, thereby forming a pre-combustion chamber, wherein the ground electrodes are fixed to a wall of the main cell, and tips of the ground electrodes and the central electrode are located below a boundary surface of the main cell and the pre-combustion cell,
• wherein the pre-combustion chamber cell has a main exhaust nozzle facing the tip of the central electrode and four auxiliary exhaust nozzles surrounding the main exhaust nozzle, and
• wherein the ground electrodes extend downward from the main cell toward the pre-combustion cell and point to the tip of the central electrode, thereby forming an S-shape,
• wherein the four auxiliary exhaust nozzles are arranged with an angular interval of about 90 degrees around the main exhaust nozzle, and each of the four auxiliary exhaust nozzles has a diameter of about 1.0 Φ to about 1.4 Φ, when the main exhaust nozzle has a diameter of about 1.2 Φ to about 1.4 Φ,
• wherein the pre-combustion chamber cell has a diameter of about 14 mm to about 18 mm, and a height of about 6 mm to about 7 mm.