Abstract: A plasma ignition plug for an internal combustion engine has a thorium alloyed tungsten anode separated from a vanadium- or beryllium-alloyed copper cathode by a boron nitride ceramic powder insulator. A generally semi-spherical titanium emitter is electrically coupled to the anode and disposed within an end of the insulator so as to form an annular gap with a torus on the end of the cathode. The surface of the emitter protrudes slightly beyond the rim of the torus on the cathode. High amplitude pulses driven into the anode arc across the annular gap to the cathode at more than twenty-four spots simultaneously, generating a plasma ignition front.

Abstract: The present invention provides a technique of suppressing the generation of radio noise in a spark plug, wherein a high dielectric constant fixation-assisting member, formed of a high dielectric constant material which is higher in dielectric constant than alumina, is provided between a metallic shell and a second conductive portion CP2 which includes a metallic terminal of the spark plug 100.

Abstract: A method of manufacturing a center electrode for a spark plug, the method including the steps of: resistance welding a sphere of a noble metal to a center electrode of a spark plug to provide a center electrode with an electrode tip that has a tip portion of a first configuration, the first configuration having a first height and a first width; and shaping the tip portion after the sphere is welded to the center electrode by a process wherein the tip portion will have a second configuration having a second height and a second width, the second height being greater than the first height and the second width being less than the first width wherein a peripheral edge of the noble metal is flush with a peripheral edge of the material it is secured to.

Abstract: Ir alloy firing tips are bonded on opposed surfaces of a center electrode and a ground electrode facing to a discharge gap. The configuration of a cross-sectional area of the Ir alloy firing tip taken along a plane perpendicular to the axis of the Ir alloy firing tip is out of round. In this cross-sectional area of this Ir alloy firing tip, when it is assumed that a circumscribed circle has a largest diameter A among virtual circles each contacting at least three portions of a visible outline of the cross-sectional area and an inscribed circle has a largest diameter B among inscribed circles each being coaxial with the circumscribed circle, a ratio of the diameter B to the diameter A (i.e., B/A) is equal to or larger than 0.8 and is less than 1.0.

Abstract: A method for manufacturing spark plugs with central and body electrode(s) armed with noble metal inserts, in which the tip of a central electrode which is pyramid or conic shaped with a base diameter (d), is liquefied by being pressed against a noble metal ball with diameter (d) that is mounted in the face of a welding electrode under a defined welding contact pressure and defined welding parameters. The liquefied material of the central electrode tip partially flows around the noble metal ball, and the welding electrode is separated from the central electrode after the liquefied material of the central electrode tip has solidified with noble metal ball embedded therein.

Abstract: A spark plug with lower operating temperature has an electrode with a tip which evenly distributes heat imparted to the firing end portion of the spark plug. The electrical insulating material surrounding the electrode is spaced at a predetermined distance from the firing end portion of the spark plug to allow the heat to more quickly travel away from the firing end portion. An annular groove in the first end surface of the electrical insulating material minimizes electrical surface discharge between the electrode and the annular metal shell of the spark plug. Radii at locations of change in cross-section in the bore of the annular metal shell and the electrical insulating material serve to minimize voltage breakdown.

Abstract: A spark plug for an internal combustion engine that burns fuel from a fuel source, the engine including a block assembly with a piston cylinder, a fluid combustion chamber connected to the piston cylinder, and an air and fuel mixing area that communicates with the combustion chamber for delivering an air and fuel mixture to the combustion chamber. A fuel delivery system is connected to the block assembly, and the fuel delivery system has a fuel passage that communicates with the fuel mixing area. The fuel delivery system has a delivery nozzle connected to the fuel passage and being directed toward the fuel mixing area, and the delivery nozzle is sized to spray a selected amount of fuel into the mixing area for mixing with air therein to provide an air and fuel mixture having an air-to-fuel ratio in the range of 90:1 to 240:1. A fuel line is connected to the fuel source and the fuel delivery system to carry the fuel from the fuel tank to the fuel delivery system.

Abstract: A spark plug with a sphere-like center discharge electrode is obtained by pressing a sphere-like metal essentially consisting of noble metal Au, Ag and/or alloys thereof with Pd or the like set on a small end bore formed at a discharge end bottom of a ceramic insulator. Sealing of a sealing material and/or resistor material together with setting (sealing) of a terminal body may be done simultaneously with the pressing of the sphere-like metal on the small end bore by means of hot-pressing applied on the terminal rod head.

Abstract: The spark plug has been designed so as to, be capable of being disassembled for cleaning, have a substantially full shield for the spark gap end of the center electrode portion, enable the center electrode to be readily replaced, if desired, enable partial cleaning of the spark plug gap area without removal of the spark plug from an associated engine, and have a substantially full gas seal defined between the base of the spark plug and the spark plug insulative sleeve.