EP 1079487 A1 20010228 - Spark plug for internal combustion engine
Title (en)
Spark plug for internal combustion engine
Title (de)
Zündkerze für Verbrennungsmotoren
Title (fr)
Bougie d'allumage pour moteurs à combustion interne
Publication
Application
Priority
JP 23886799 A 19990825
Abstract (en)
A spark plug for an internal combustion engine is comprised of a center electrode (3), a cylindrical insulator (2) holding the center electrode in a center hole thereof, a cylindrical metal housing (1) holding the insulator therein, a first earth electrode (4) having a free end disposed opposite the center electrode's edge to form a first discharge gap A, a second earth electrode (5, 6) having a free end disposed opposite the center electrode's side-surface to form a second discharge gap. The free end of the second earth electrode has a cross-sectional area S1 at a portion normally opposite to the insulator's side surface. The insulator's side surface has a projected area S2 to which the free end of the second earth electrode is normally projected. The free end of the second earth electrode is disposed at a portion outside the outside diameter B of the insulator's edge. There is the following relationship between the first discharge gap A and the outside diameter B: B . 5A - 2.5 (mm). <IMAGE>
IPC 1-7
IPC 8 full level
H01T 13/14 (2006.01); H01T 13/20 (2006.01); H01T 13/46 (2006.01); H01T 13/52 (2006.01)
CPC (source: EP)
H01T 13/14 (2013.01); H01T 13/52 (2013.01)
Citation (search report)
- [A] GB 1373435 A 19741113 - BOSCH GMBH ROBERT & JP S4719236 A
- [PX] EP 0964490 A2 19991215 - NGK SPARK PLUG CO [JP]
Designated contracting state (EPC)
DE FR GB
DOCDB simple family (publication)
EP 1079487 A1 20010228; EP 1079487 B1 20080206; DE 60037955 D1 20080320; DE 60037955 T2 20090319; JP 2001068251 A 20010316; JP 3721877 B2 20051130
DOCDB simple family (application)
EP 00118389 A 20000824; DE 60037955 T 20000824; JP 23886799 A 19990825