Other

Kazumi Kawamura

Akira Suzuki

Takahiro Suzuki

Kazuya Iwata

A spark plug has a central electrode, an insulator surrounding the central electrode and a metallic shell retaining therein the insulator and provided with no thread thereon. The spark plug is clearance fitted in a plug hole of a cylinder head, without being screwed into the plug hole, in such a manner that a front end portion of the metallic shell is accommodated in a front end section of the plug hole with a clearance therebetween provided with a sealant so as to transmit heat from the spark plug to the cylinder head. The clearance is preferably given by the following expression: 0.005&lE;D&minus;d &lE;0.05, where D is an inner diameter (mm) of the front end section and d is an outer diameter (mm) of the front end portion. By this, the spark plug can be easily attached to the cylinder head and attain improved heat resistance.

Growing community of inventors

14-18, Takatsuji-cho, Mizuho-ku, Nagoya-shi, Aichi 467-8525, Japan

Kazumi Kawamura