US 8,552,629 B2Granted

Spark plug designed to ensure desired degree of ignitability of fuel

AssigneesNippon Soken, Inc., Denso Corporation

InventorsTakayuki Inohara, Shinichi Okabe, Takanobu Aochi, Atsushi Iwami, Masamichi Shibata

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Abstract

A spark plug for an internal combustion engine is provided which is equipped with a tip protrusion disposed on a top of a hollow cylindrical housing of the spark plug. The spark plug also includes a center electrode retained in a porcelain insulator disposed inside the housing and a ground electrode is joined to the housing so as to form a spark gap. The tip protrusion serves to direct a flow of gas to be ignited by a spark produced in the spark gap and is shaped to have a radial width extending in a radial direction of the housing and a circumferential width extending in a circumferential direction of the cylindrical housing. The radial width is greater than the circumferential width. This enhances the efficiency in guiding the flow of gas toward the spark gap.

Claims8

Dependent claims

A spark plug for an internal combustion engine comprising:

a hollow cylindrical housing which has an open end;
a cylindrical porcelain insulator retained in the cylindrical housing;
a center electrode having a given length which is retained in the porcelain insulator with a tip thereof exposed outside an end of the porcelain insulator;
a ground electrode which is joined to the cylindrical housing so as to form a spark gap between itself and the tip of the center electrode;
and
a tip protrusion which extends from the open end of the cylindrical housing, the tip protrusion being shaped to have a radial width that is a width extending in a radial direction of the cylindrical housing and a circumferential width that is a width extending in a circumferential direction of the cylindrical housing, the radial width being greater than the circumferential width.

3 more elements

Dependencies are inferred from the claim text.