Abstract: A spark plug having a multilayer firing tip that minimizes the amount of precious metal used and a method of assembling a spark plug with a multilayer firing tip. The firing tip includes a discharge end and a weld end, with the weld end being connected to a center electrode, and more specifically to a base electrode on the center electrode. The weld end has a coefficient of thermal expansion, which is not between the values for the coefficients of thermal expansion for the discharge end and the base electrode. More specifically, the weld end has a coefficient of thermal expansion which is greater than the coefficients of thermal expansion for the discharge end and base electrode. The weld end is formed from Nickel and Chromium with a limited amount of additional elements. The spark plug is assembled by providing a first elongated material formed from the material used for the discharge end and a second elongated material formed from a material used for the weld end.

Abstract: A spark plug having a multilayer firing tip that minimizes the amount of precious metal used and a method of assembling a spark plug with a multilayer firing tip. The firing tip includes a discharge end and a weld end, with the weld end being connected to a center electrode, and more specifically to a base electrode on the center electrode. The weld end has a coefficient of thermal expansion, which is not between the values for the coefficients of thermal expansion for the discharge end and the base electrode. More specifically, the weld end has a coefficient of thermal expansion which is greater than the coefficients of thermal expansion for the discharge end and base electrode. The weld end is formed from Nickel and Chromium with a limited amount of additional elements. The spark plug is assembled by providing a first elongated material formed from the material used for the discharge end and a second elongated material formed from a material used for the weld end.

Abstract: A spark plug having a multilayer firing tip that minimizes the amount of precious metal used and a method of assembling a spark plug with a multilayer firing tip. The firing tip includes a discharge end and a weld end, with the weld end being connected to a center electrode, and more specifically to a base electrode on the center electrode. The weld end has a coefficient of thermal expansion, which is not between the values for the coefficients of thermal expansion for the discharge end and the base electrode. More specifically, the weld end has a coefficient of thermal expansion which is greater than the coefficients of thermal expansion for the discharge end and base electrode. The weld end is formed from Nickel and Chromium with a limited amount of additional elements. The spark plug is assembled by providing a first elongated material formed from the material used for the discharge end and a second elongated material formed from a material used for the weld end.

Abstract: A spark plug having a pair of independent spark gaps includes a shell, inner and outer insulators, a cylindrical electrode assembly, a center wire assembly, and a pair of ground electrodes. The cylindrical electrode assembly is generally located between the two insulators and delivers a first high voltage ignition pulse to a first spark gap. The center wire assembly is located in an axial bore of the inner insulator and delivers a second high voltage ignition pulse to a second spark gap. The two insulators and two electrode assemblies are all coaxially aligned within the shell so that both insulators can be rotationally symmetrical. The first spark gap is radially oriented while the second spark gap is axially oriented, and the first and second spark gaps are located at different axial positions and can fire independently of one another. A method of assembling the spark plug is also disclosed.

Abstract: A sparkplug having ground and center electrodes that include a firing tip formed from a noble metal or noble metal alloy by reflowing of a noble metal preform. The present invention also includes a method of manufacturing a metal electrode having an ignition tip for an ignition device, including forming a metal electrode having a firing tip portion; applying a noble metal preform to the firing tip portion; and reflowing the noble metal preform to form a noble metal firing tip.

Abstract: A spark plug having a center electrode assembly that includes a center electrode and precious metal insert that is both mechanically interlocked and welded to the center electrode in a manner that permits trapped gases to escape from between the two components. Also disclosed is a method for manufacturing the same. During assembly, the precious metal insert is placed into a blind hole that extends axially into a lower end of the center electrode. Once in place, the center electrode is deformed around an enlarged head section of the insert to mechanically interlock the two components together. To further strengthen this attachment, the two components are welded together about their circumference. In one embodiment, the weld includes several interruptions that function as vapor vents for any gases that may be trapped. In other embodiments, a radially or an axially-extending vent hole is used in lieu of the weld interruptions.

Abstract: An ignition and diagnostic system (10) for an internal combustion engine includes a sparking device (12) through which a low voltage diagnostic device (54) monitors a sensing feature, for example spark gap (30) conditions, during spark intervals and returns diagnostic feedback to an engine control module (56). A coil (44) is electrically operatively connected to the sparking device (12) through a lead wire (48). The lead wire (48) can be removed and reinstalled with respect to the sparking device (12) via a flexor joint (60) for installation and maintenance. The flexor joint (60) enables positive electrical contact during operation so that low voltage signals from the diagnostic device (54) are maintained even during severe vibration conditions. The flexor joint (60) comprises in one embodiment a compression spring (62) which is fully compressed or over-compressed.