Spark plug with multi-point firing cap

A spark plug, comprising:

• (a) a central electrode having a proximal end and a distal end;
• and
• (b) a cap having a central portion and plural projections extending radially from the central portion, wherein
• (i) the cap has a proximal side and a distal side and the proximal side of the cap is attached to the distal end of the central electrode,
• (ii) the cap is comprised mostly of a first material having a first electrical conductivity and also of a second material having a second electrical conductivity that is lower than the first electrical conductivity, and
• (iii) the second material is disposed toward the distal side of the cap.

A method for manufacturing a spark plug, comprising:

• (a) fabricating a cap having a central portion and plural projections extending radially from the central portion, wherein the central portion of the cap defines a hole through the cap, the hole having a depth;
• (b) inserting an electrode into the hole, but only through a portion of the depth of the hole;
• (c) heating the cap and the electrode so that fusion begins to occur;
• and
• (d) depositing attachment material so as to fill at least a portion of the depth of the hole not occupied by the electrode.

A spark plug comprising:

• (a) a central electrode having a distal end and a proximal end;
• (b) an insulator surrounding the central electrode;
• (c) a shell surrounding the insulator and having a wall portion extending at its distal end, wherein the wall portion has a proximal firing surface and defines a plurality of holes in the cylindrical wall thereof;
• and
• (d) a cap attached to the proximal end of said central electrode and having a plurality of projections protruding radially from the periphery thereof,
• wherein the central electrode, the insulator, and the shell are disposed in a concentric arrangement and the cap is concave,
• wherein the cylindrical extension and the cap are spaced apart to define a spark gap between said firing surface of the extension and said projections on the periphery of the cap, and
• wherein the cylindrical extension is configured such that said holes comprise between about 20% and 40% of the total surface area of said wall of said cylindrical extension.