Patent ID: 7812509

Claim:
A spark plug, comprising: a plug body; a center electrode provided on the plug body coaxially with the plug body; a ground electrode provided on the plug body in a vicinity of the center electrode, and having a portion opposing an end of the center electrode along an axis of the plug body, a tip of the ground electrode intersecting an axis of the plug body and opposing a tip of the center electrode; and at least one injection control side pole provided on the plug body in the vicinity of the center electrode, a tip of the at least one injection control side pole being separated from the tip of the ground electrode, and the tip of the ground electrode and the tip of the at least one injection control side pole being positioned on substantially the same plane perpendicular to the axis, the ground electrode and the at least one injection control side pole being arranged at substantially regular intervals around the center electrode, wherein a maximum length of the ground electrode along a center axis of the plug body is substantially the same as a maximum length of the at least one injection control side pole along the center axis, and a width of the ground electrode along a circumference of the center electrode is substantially the same as a width of the at least one injection control side pole along the circumference of the center electrode.