Spark plug having firing pad
AssigneeFederal-Mogul Ignition Company
InventorsKevin J. Kowalski, Frederick J. Quitmeyer, Nathan A. Thomson, Curtis W. Verhoff, Richard L. Keller
Life of this patent
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Abstract
A spark plug has a firing pad attached to a center electrode or a ground electrode by way of a fused portion. In one or more embodiments, the firing pad is composed of a precious metal material. The fused portion can be formed in such a way that a material composition thereof at a sparking surface of the firing pad has a greater percentage of the precious metal material than a material of the underlying electrode to which the firing pad is attached.
Claims20
A spark plug, comprising:
- a metallic shell having an axial bore;
- an insulator having an axial bore and being disposed at least partially within the axial bore of the metallic shell;
- a center electrode being disposed at least partially within the axial bore of the insulator;
- a ground electrode being attached to the metallic shell;
- and
- a firing pad of a precious metal material attached to the center electrode or to the ground electrode via a fused portion, wherein the fused portion is located largely inboard of a peripheral edge (P) of the firing pad and penetrates entirely through a thickness (T2) of the firing pad and through a surface-to-surface interface (S) between the firing pad and the electrode to which the firing pad is attached, and the fused portion includes a sparking surface made from solidified precious metal material formed in a temporary cavity created by vaporization from impingement of a laser beam on the firing pad.
A spark plug, comprising:
- a metallic shell having an axial bore;
- an insulator having an axial bore and being disposed at least partially within the axial bore of the metallic shell;
- a center electrode being disposed at least partially within the axial bore of the insulator;
- a ground electrode being attached to the metallic shell;
- and
- a firing pad attached to the center electrode or to the ground electrode via a keyhole weld including a solidified precious metal section located at least at a sparking surface of the firing pad and comprised of precious metal material of the firing pad that, amid its formation, was driven from an adjacent sparking surface into a temporary cavity created by vaporization via impingement of a laser beam, and the keyhole weld including a solidified mixture section located at least below a surface-to-surface interface (S) between the firing pad and the electrode to which the firing pad is attached, the mixture section comprised of precious metal material of the firing pad and material of the electrode mixed together via impingement of the laser beam.
A spark plug electrode assembly, comprising:
- an electrode;
- and
- a thin firing pad of a precious metal material attached to the electrode via a fused portion, the thin firing pad having a greatest width dimension (W) across a sparking surface that is at least several times greater than a greatest thickness dimension (T2) of the thin firing pad, wherein a material composition of the fused portion at a sparking surface of the thin firing pad includes a greater percentage of the precious metal material than a material of the electrode, and wherein the fused portion extends into the electrode to a depth (D2) taken from a surface-to-surface interface (S) between the thin firing pad and the electrode that is greater than a thickness dimension (T2) of the thin firing pad.
Dependencies are inferred from the claim text.