SPARK PLUG FOR INTERNAL COMBUSTION ENGINE

• Main Author: SUGIURA AKIMITSU
• Format: Patent
• Language: English; Japanese
• Published: 10.08.2021
• Subjects: BASIC ELECTRIC ELEMENTS; CORONA DEVICES; ELECTRICITY; GENERATING IONS TO BE INTRODUCED INTO NON-ENCLOSED GASES; OVERVOLTAGE ARRESTERS USING SPARK GAPS; SPARK GAPS; SPARKING PLUGS

To provide a spark plug for internal combustion engine capable of improving ignitability.SOLUTION: A spark plug 1 for internal combustion engine comprises a cylindrical insulator, a center electrode 4, a cylindrical housing and an auxiliary chamber formation part 5. The auxiliary chamber formation part 5 covers at least a portion of the center electrode 4. A diameter of a tip end penetrating hole 51 formed in the auxiliary chamber formation part 5 is enlarged toward a tip end. A diameter enlarged part 42 whose diameter is enlarged toward the tip end is provided in an electrode tip end part 41 that is a tip end portion of the center electrode 4. At least a portion of the diameter enlarged part 42 is disposed inside of the tip end penetrating hole 51. An annular injection path 52 is formed between an outer peripheral inclined plane 421 of the diameter enlarged part 42 and an inner peripheral inclined plane 512 of the tip end penetrating hole 51. The annular injection path 52 is formed so as to be away from a plug center axis C as getting closer to the tip end. An inner peripheral end 511 of the tip end penetrating hole 51 constitutes a ground electrode which forms a discharge gap G between the inner peripheral end and an electrode tip end part 41 of the center electrode 4.SELECTED DRAWING: Figure 3 【課題】着火性を向上させることができる内燃機関用のスパークプラグを提供すること。【解決手段】内燃機関用のスパークプラグ１は、筒状の絶縁碍子と、中心電極４と、筒状のハウジングと、副室形成部５とを有する。副室形成部５は、中心電極４の少なくとも一部を覆う。副室形成部５に形成された先端貫通孔５１は、先端へ向かうほど拡径している。中心電極４の先端部である電極先端部４１には、先端へ向かうほど拡径する拡径部４２が設けてある。拡径部４２の少なくとも一部は先端貫通孔５１の内側に配されている。拡径部４２の外周斜面４２１と、先端貫通孔５１の内周斜面５１２との間には、環状噴出路５２が形成されている。環状噴出路５２は、先端側へ向かうほどプラグ中心軸Ｃから遠ざかるように形成されている。先端貫通孔５１の内周端部５１１は、中心電極４の電極先端部４１との間に放電ギャップＧを形成する接地電極を構成している。【選択図】図３