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US 5,017,826 AGranted
Rapid heat-dissipating type spark plug for internal combustion engines
AssigneeNgk Spark Plug Co., Ltd.
InventorsTakafumi Oshima, Kozuka Kazuhiko
Life of this patent
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Abstract
A rapid heat-dissipating type spark plug has a metallic shell which is made of material having a tensile stress of more than 40 Kg/mm.sup.2 with a thermal conductivity of more than 60 W/m.multidot.k. In another embodiment, there is provided a ground electrode which is made of nickel or nickel alloy. The ground electrode is connected to the metallic shell through a metallic ring which is made of different metal from the metallic shell such as steel, stainless steel or nickel alloy.
Claims7
A spark plug structure comprising;
- a cylindrical metallic shell;
- a tubular insulator having a center bore, and;
- a center electrode placed into the center bore of the insulator to form a spark gap with a ground electrode depending from the metallic shell;
- the metallic shell being made of material having a tensile stress of more than 40 Kg/mm.sup.2, and having a thermal conductivity of more than 60 W/m.multidot.k.
1 more element
A spark plug structure comprising;
- a cylindrical metallic shell having a ground electrode at its front end which has a thermal conductivity of more than 60 W/m.multidot.k;
- a tubular insulator having a center bore, and at least a front end of the insulator having a good thermal conductivity of more than 60 W/m.multidot.k, and placed into the metallic shell;
- a center electrode placed into the center bore of the insulator with a front end somewhat extended from that of the insulator;
- a terminal inserted into the center bore of the insulator in alignment with the center electrode;
- an electrically conductive glass sealant provided at an annular space between the insulator and the terminal, and one between the insulator and the center electrode;
- the ground electrode being made of nickel or nickel alloy, the ground electrode being connected to the metallic shell through a metallic ring which is made of different metal from the metallic shell selected from the group consisting of steel, stainless steel and nickel alloy.
3 more elements
Dependencies are inferred from the claim text.