Spark plug and an internal combustion engine igniting system using the same

摘要

A spark plug having a center electrode (2), a ground electrode (4), and an insulator (3). The ground electrode (4) has a firing surface (4a) formed in a tip end side, and the firing surface (4a) is opposed to a side face of the center electrode (2). The insulator (3) covers the outside of the center electrode (2) and is placed such that a tip end portion (3a) is between the side face of the center electrode (2) and the firing surface (4a) of the ground electrode (4). A discharge high voltage is applied across the center electrode (2) and the ground electrode (4) such that a polarity of the center electrode (2) is positive and that of the ground electrode (4) is negative. The high voltage causes a spark discharge to be generated between the firing surface (4a) of the ground electrode (4) and a tip end portion of the center electrode (2). <IMAGE>