SPARK PLUG FOR INTERNAL COMBUSTION ENGINES

• Main Author: SUGIURA AKIMITSU
• Format: Patent
• Language: English; Japanese
• Published: 09.02.2023
• 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 engines capable of suppressing misfire when starting an internal combustion engine.SOLUTION: A spark plug for internal combustion engines 1 includes: a center electrode 4 and a ground electrode 6 that form a discharge gap G therebetween; and plug cover 5 formed at the tip so as to cover a sub-combustion chamber 50 where the discharge gap G is arranged. In the plug cover 5, a nozzle hole 51 that communicates the sub-combustion chamber 50 with the outside is formed. Defining that the inner diameter of the injection hole 51 as D, the length along the injection hole axis of the injection hole 51 as L, and the contact angle between the inner wall surface of the injection hole 51 and water as θ, at least one injection hole 51 satisfies the following formula (1): (L/2)×tan(θ/2)<D (1)SELECTED DRAWING: Figure 1 【課題】内燃機関の始動時における失火を抑制す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、互いの間に放電ギャップＧを形成する中心電極４及び接地電極６と、放電ギャップＧが配される副燃焼室５０を覆うよう先端部に設けられたプラグカバー５と、を有する。プラグカバー５には、副燃焼室５０と外部とを連通させる噴孔５１が形成されている。少なくとも一つの噴孔５１は、当該噴孔５１の内径をＤ、当該噴孔５１の噴孔軸に沿った長さをＬ、当該噴孔５１の内壁面と水との接触角をθとしたとき、下記式（１）を満たす。（Ｌ／２）×ｔａｎ（θ／２）＜Ｄ （１）【選択図】図１