SPARK PLUG Russian patent published in 2007 - IPC H01T13/20 H01T13/54 

FIELD: electrical equipment of internal-combustion engines; fuel injection in carburetor and injection-type engines.

SUBSTANCE: proposed spark plug has body accommodating insulator with central stick electrode; butt-end of body dipped into engine cylinder has hemispherical depression whose center is on longitudinal horizontal axis and tangential holes are made on cylindrical part of body between butt-end and threaded surface of body to provide communication between precombustion chamber and engine cylinder space; depression depth h is interrelated with hemisphere radius R by expression 0.2 ≤ hR ≤ 0.5.

EFFECT: enhanced reliability of ignition and operation, extended service life of plug.

1 cl, 3 dwg