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US 6,548,944 B1Granted
Spark plug having insulating oil
AssigneeDenso Corporation
InventorYoshiki Morita
Life of this patent
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Abstract
In a spark plug, an annular seal packing is arranged in a gap defined between an insulator and a fitting. Electrically insulating oil is filled in an oil-retaining section of the gap that is located on the distal side of the packing. The oil-retaining section of the gap is the continuous section having a width ranging from 0.05 mm to 0.3 mm and an axial length of 2 mm or more from the packing. The filled insulating oil is retained within the oil-retaining section of the gap by its surface tension while it is in a liquid state.
Claims9
A spark plug comprising:
- a central electrode;
- an insulator disposed outside of said central electrode;
- a fitting disposed outside of said insulator, wherein said fitting and said insulator define a gap between them;
- a ground electrode having a proximal end electrically connected with a distal end of said fitting and also having a distal end arranged to face said central electrode;
- an annular seal member disposed in said gap;
- and
- electrically insulating oil filled in an oil-retaining section of said gap that is located on the distal side of said seal member, wherein said oil-retaining section of said gap extends axially and continuously for a length of at least 2 mm and has a profile that allows retention of said electrically insulating oil within said oil-retaining section of said gap by a surface tension of said electrically insulating oil while said electrically insulating oil is in a liquid state.
4 more elements
Dependencies are inferred from the claim text.