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 shell, an insulator, a center electrode, a ground electrode, and a firing pad. The firing pad is made of a precious metal material and is attached to the ground electrode. The firing pad has a side surface at a peripheral edge that can be flush or nearly flush with a free end surface of the ground electrode. This construction can help improve ignitability and flame kernel growth of the spark plug during a sparking event, and can provide better thermal management at the attached ground electrode and firing pad.
Claims18
A spark plug, comprising:
- a shell having an axial bore;
- an insulator having an axial bore and being disposed at least partially within the axial bore of the shell;
- a center electrode disposed at least partially within the axial bore of the insulator;
- a ground electrode attached to the shell and having a free end surface;
- and
- a firing pad made of a precious metal material attached to the ground electrode, the firing pad having a side surface at a peripheral edge (P) of the firing pad, wherein the free end surface of the ground electrode and the side surface of the firing pad are flush or nearly flush relative to each other.
A method of preparing a ground electrode and firing pad assembly, the method comprising the steps of:
- trimming a free end portion of the ground electrode, leaving a trimmed free end surface;
- locating the firing pad at the free end portion, the firing pad having a side surface located at or near the trimmed free end surface of the ground electrode;
- and
- emitting a laser beam to the firing pad and inboard of the side surface at an extent of the side surface that is located at or near the trimmed free end surface.
A method of preparing a ground electrode and firing pad assembly, the method comprising the steps of:
- laser welding the firing pad to a free end portion of the ground electrode, the laser welding producing a weldment, the firing pad having a side surface;
- and
- trimming the free end portion of the ground electrode along a trim line situated at or near the side surface of the firing pad, wherein the weldment is positioned inboard of the side surface at least where the trim line is situated at or near the side surface.
Dependencies are inferred from the claim text.