SPARK PLUG FOR INTERNAL COMBUSTION ENGINE

摘要

A spark plug includes a tubular housing, a tubular insulator, a center electrode, a ground electrode, a resistor, and a stem. The insulator is supported inside the housing. The center electrode is supported inside the insulator so as a distal end portion thereof protrudes. The ground electrode forms a spark discharge gap G between the ground electrode and the center electrode. The resistor is supported inside the insulator at a proximal side of the central electrode. The stem is supported inside of the insulator at a proximal side of the resistor. Of an outer peripheral surface of the insulator, and closer to a distal end side than a proximal portion of the resistor is, there is formed a high emissivity surface of which thermal emissivity is at least 0.7 on at least a part of a portion facing an inner circumferential surface of the housing.

主权项

1. A spark plug for an internal combustion engine comprising:
a tubular housing; a tubular insulator supported inside the housing; a center electrode supported inside the insulator so that a distal end portion, which is a portion inserted into a combustion chamber of the internal combustion engine, of the center electrode protrudes; a ground electrode that forms a spark discharge gap between the ground electrode and the center electrode; a resistor supported inside the insulator at a proximal side, which is a side opposite to the distal end, of the central electrode; and a stem supported inside the insulator at a proximal side of the resistor; wherein, of an outer peripheral surface of the insulator, and closer to a distal end side than a proximal portion of the resistor is, there is formed a high emissivity surface of which thermal emissivity is at least 0.7 on at least a part of a portion facing an inner circumferential surface of the housing.