Spark plug
AssigneeNgk Spark Plug Co., Ltd.
InventorsWataru Matsutani, Masayuki Segawa, Satoko Ito
Life of this patent
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Abstract
A spark plug having a discharge portion formed of a noble-metal chip, the spark plug being capable of restraining wear observed on a slenderized discharge portion in particular. Discharge portion (31) includes noble-metal chip (31′). Dimension D is 0.3-0.8 mm; and H is 0.4-2 mm, where D (mm) is a diameter representing the outside diameter of the noble-metal chip, and H (mm) is a discharge portion thickness representing the shortest distance between the periphery of a discharge face (31t) and a corresponding end edge of a weld zone W where a center electrode (3) and the noble-metal chip (31′) are welded. Further, the noble-metal chip (31′) contains a predominant amount of Ir and 0.5-8% by weight Ni.
Claims17
A spark plug comprising a center electrode and a ground electrode, which is disposed such that a side surface thereof faces an end face of the center electrode, and having a discharge portion having a discharge face formed, by welding of a noble-metal chip, on the center electrode at a position corresponding to a spark discharge gap, said noble-metal chip projecting from the center electrode between a periphery of the discharge face and a weld portion, said spark plug being characterized in that:
- D is 0.3-0.8 mm;
- and
- H is 0.4-2 mm,
- where D (mm) is a chip diameter representing an outside diameter of the noble-metal chip;
- and H (mm) is a discharge portion thickness representing a shortest distance between a periphery of the discharge face and a corresponding end edge of a weld zone where the noble-metal chip and the center electrode are welded, said spark plug being further characterized in that:
- the noble-metal chip contains a predominant amount of Ir and 0.5-8% by weight Ni.
A spark plug comprising a center electrode and a ground electrode, which is disposed such that a side surface thereof faces an end face of the center electrode, and having a discharge portion having a discharge face formed, by welding of a noble-metal chip, on at least either the center electrode or the ground electrode at a position corresponding to a spark discharge gap, said spark plug being characterized in that:
- the noble-metal chip comprises an Ir—Ni alloy containing 0.5-8% by weight of Ni and 1-5% by weight of at least one of Ru and Re.
A spark plug comprising a center electrode and a ground electrode, which is disposed such that a side surface thereof faces an end face of the center electrode, and having a discharge portion having a discharge face formed, by welding of a noble-metal chip, on at least either the center electrode or the ground electrode at a position corresponding to a spark discharge gap, said spark plug being characterized in that:
- the noble-metal chip comprises an Ir base alloy containing 0.5-40% by weight of Rh and 1-4% by weight of Ni.
A spark plug comprising a center electrode and a ground electrode, which is disposed such that a side surface thereof faces an end face of the center electrode, and having a discharge portion having a discharge face formed, by welding of a noble-metal chip, on the ground electrode at a position corresponding to a spark discharge gap, said spark plug being characterized in that:
- D is 0.3-0.8 mm;
- and
- H is 0.4-2 mm,
- where D (mm) is a chip diameter representing an outside diameter of the noble-metal chip;
- and H (mm) is a discharge portion thickness representing a shortest distance between a periphery of the discharge face and a corresponding end edge of a weld zone where the noble-metal chip and the center electrode are welded, said spark plug being further characterized in that:
- the noble-metal chip contains a predominant amount of Ir and 1-4% by weight Ni.
Dependencies are inferred from the claim text.