Patent ID: 7443089

Claim:
A spark plug for a spark-ignited internal combustion engine, said spark plug comprising: an elongated ceramic insulator having an upper terminal end, a lower nose end, and a central passage extending longitudinally between said terminal and nose ends; said insulator including an exterior surface presenting a generally circular large shoulder proximate said terminal end and a generally circular small shoulder proximate said nose end, said large shoulder having a diameter greater than the diameter of said small shoulder, and further including a filleted transition between the disparate diameters of said large and small shoulders; a conductive shell surrounding at least a portion of said insulator, said shell including at least one ground electrode; a conductive terminal stud partially disposed in said central passage and extending longitudinally from an exposed top post to a bottom end embedded within said central passage; a conductive center electrode partially disposed in said central passage and extending longitudinally between a head encased within said central passage and an exposed sparking tip proximate said ground electrode, said head being longitudinally spaced from said bottom end of said terminal stud within said central passage; a suppressor seal pack disposed in said central passage and electrically connecting said bottom end of said terminal stud with said head of said center electrode for conducting electricity therebetween while sealing said central passage and suppressing radio frequency noise emissions from said spark plug, said suppressor seal pack having a first cross-sectional area at said bottom end of said terminal stud and a second cross-sectional area at said head of said center electrode, said first cross-sectional area being greater than said second cross-sectional area; and said suppressor seal pack including a reducing taper for progressively transitioning from said greater first cross-sectional area to said lesser second cross-sectional area, said reducing taper being longitudinally located in a region bounded at its uppermost limit by said bottom end of said terminal stud and at its lowermost limit by said filleted transition.