Abstract: An ignition system includes an ignition plug, a discharge power supply for applying a high voltage to the gap of the ignition plug, a high-frequency power supply for supplying a high-frequency current to the gap, a matching unit provided between the ignition plug and the high-frequency power supply, and a mixer through which currents output from the two power supplies flow. An oscillation frequency fs (Hz) which maximizes the current flowing between the matching unit and the mixer when spark discharge is generated and an oscillation frequency fo (Hz) which maximizes the current flowing between the matching unit and the mixer when spark discharge is not generated satisfy a relation fs/fo?0.85. Thus, a current whose oscillation frequency is equal to the oscillation frequency fs flows between the matching unit and the mixer when spark discharge is not generated.

Abstract: A spark plug includes a center electrode, a ground electrode, and a tip joined to the center electrode and forming a spark discharge gap with the ground electrode. The tip is joined to the center electrode via a fusion zone, which has an exposed surface exposed to the external environment. In a section containing an axis and the center of the exposed surface, C?B?0.02 is satisfied, where C (mm) is the distance on the side surface of the tip between the fusion zone and the distal end of the tip, and B (mm) is the distance between a distal end surface of the tip and a portion of the fusion zone located closer to the axis than the side surface of the tip and located closest in the fusion zone to the distal end surface of the tip.

Abstract: A spark plug includes a center electrode extending along an axial line, a ground electrode, and a noble metal tip. A center axis of the noble metal tip is displaced from a center axis of the ground electrode toward a base-end side in the axial line. The ground electrode includes an outer layer and an inner layer, and a distal end of the inner layer is closer to the axial line than a base end of the ground electrode. An overlap area between the inner layer and the noble metal tip occupies a ratio of 25% or more in a projective plane defined by projecting, along the center axis, a plane of the ground electrode viewed from a distal-end face on a cross section of the ground electrode in which a maximum cross-sectional area of the inner layer is achieved, among cross sections orthogonal to the center axis.

Abstract: A spark plug includes a center electrode extending in an axial direction; an insulator formed externally of the outer circumference of the center electrode; a metallic shell formed externally of the outer circumference of the insulator and having a ledge which supports the insulator; and a ground electrode joined to the metallic shell. The insulator has a support portion which faces the ledge. A “frontward direction” is defined as the direction parallel to the axial direction toward a spark portion formed between the center electrode and the ground electrode. The insulator has a diameter reduction portion whose outside diameter reduces along the frontward direction from the support portion, and a diameter increase portion whose outside diameter increases along the frontward direction from the front end of the diameter reduction portion. This restrains the generation of leak current while maintaining heat resistance of the spark plug.

Abstract: A method for improving welding strength between a ground electrode and a noble metal tip on a spark plug. A fusion zone is formed along at least a portion of the boundary between the ground electrode and the noble metal tip through fusion of a portion of the ground electrode and a portion of the noble metal tip.

Abstract: A superior ignitability is realized assuredly by specifying at least either of a relation in magnitude between absolute values of a plus-side voltage and a minus-side voltage and a relation in magnitude between absolute values of a plus-side current and a minus-side current when alternating current power is introduced. An ignition system includes a spark plug, a discharging power supply which applies a voltage to a spark gap of the spark plug to thereby generate an electric spark discharge and an alternating current power supply which introduces alternating current power to an electric spark generated by the electric spark discharge to generate an alternating current plasma.

Abstract: An ignition device (100) includes a power supply (2) for discharge; an AC power supply (3); an ignition coil (41) for generating a secondary voltage in a secondary coil (41B); an ignition plug (1) connected to the secondary coil (41B); an AC electrode (43) electrically connected to the AC power supply (3); a high-voltage electrode (42) located between the secondary coil (41B) and the ignition plug (1); an insulator (44) located between the two electrodes (42, 43); and a second insulator (47) which covers the ignition coil (41) and a capacitor (49) composed of the two electrodes (42, 43) and an insulator (44). The secondary voltage and AC power are supplied to the ignition plug (1) via the high-voltage electrode (42). Thus, excellent ignition performance can be implemented while the occurrence of misfire is restrained.

Abstract: A technique of improving the life of a spark plug which generates spark discharge and AC plasma. A plasma ignition device includes a power control section which reduces AC power P after generation of AC plasma in an AC power supply period Sa during which the AC power P is continuously supplied to a spark plug within a maintainable power range Rp within which the AC plasma can be maintained.

Abstract: A method of manufacturing a spark plug having an insulator, a center electrode, a metallic shell, a ground electrode, and a noble metal tip provided on the ground electrode and having a discharge surface forming a spark discharge gap in cooperation with the center electrode. The method of manufacturing includes a fusion-zone formation step of forming a fusion zone through radiation of a high-energy beam to the boundary between the ground electrode and the noble metal tip.

Abstract: In a spark plug, a fusion zone where a ground electrode and a noble metal tip are fused together is formed in at least a portion of an interfacial region between the ground electrode and the noble metal tip. When the fusion zone is projected in the axial direction, the projected fusion zone overlaps 70% or more of the area of the noble metal tip. As viewed on a section which passes through the center of gravity of the noble metal tip and is perpendicular to the longitudinal direction of the ground electrode, the relational expression 1.3?B/A is satisfied, where A is the greatest thickness of the fusion zone along the axial direction, and B is the length from a portion having the greatest thickness of the fusion zone to the inner end of the fusion zone.

Abstract: A spark plug (1) including a noble metal tip joined to a ground electrode and forming a spark discharge gap in cooperation with a center electrode. A surface of the noble metal tip which forms the gap has an area of 0.9 mm2 or greater. The noble metal tip (32) is joined to the ground electrode (27) via a fusion zone (35) formed by irradiating at least one surface among a distal end surface and side surfaces of the ground electrode with a laser beam or an electron beam. Further, as viewed on a projection plane orthogonal to a center axis of the noble metal tip and on which the noble metal tip and the fusion zone are projected along the center axis, an overlapping region between the noble metal tip (32) and the fusion zone accounts for 70% or more of a projected region of the noble metal tip.

Abstract: High-frequency plasma spark plug includes an insulator which has an axial hole extending in the axis direction, a center electrode inserted into a distal end side of the axial hole, a terminal electrode inserted into a rear end side of the axial hole, and being electrically connected to the center electrode, and a cylindrical main fitting mounted on an outer periphery of the insulator. With respect to a coaxial cable, the inner conductor is connected to the terminal electrode and the outer conductor is connected to the main fitting. High frequency power generated by a predetermined high-frequency power source is supplied via the coaxial cable thus generating high frequency plasma. The main fitting includes a large diameter portion which bulges radially outward and a connection portion which is brought into contact with the outer conductor.

Abstract: There is provided a spark plug 100 with a ground electrode 30, wherein a protrusion amount A of a protruding portion 36 satisfies a relationship of 0.4 mm?A?1.0 mm and wherein a width B from a front end surface 31 to a press recessed portion 37 satisfies a relationship of 0.4 mm?B?2.5 mm.

Abstract: An ignition system having a spark plug, a discharge power supply, and an AC power supply. Voltage from the discharge power supply and AC power from the AC power supply are supplied to a spark discharge gap through an electrode of the spark plug. The AC power from the AC power supply is applied to a spark generated by the voltage from the discharge power supply in the spark discharge gap.

Abstract: An object of the present invention is to provide an enhancing agent for effect of anticancer agent for achieving an excellent therapeutic effect on cancer. The enhancing agent for effect of anticancer agent according to the present invention which is a solving means therefor is characterized in that a nitric oxide donor is an effective ingredient. In accordance with the present invention, an excellent therapeutic effect is able to be achieved on non-small cell lung cancer which is still in such a state that no effective therapeutic method has been established yet for a progressive cancer which is not operable and is one of cancers where chemotherapy is most difficult to apply.

Abstract: A technique for lowering power loss involved in supply of high-frequency electric power to an ignition plug. The ignition plug includes a tubular insulator having an axial bore extending therethrough; a center electrode disposed in the axial bore; a metal terminal disposed rearward of the center electrode in the axial bore, electrically connected to the center electrode, and supplied with high-frequency electric power from an external source; a metallic shell disposed to circumferentially surround the insulator; and a ground electrode electrically connected to the metallic shell and adapted to generate plasma in cooperation with the center electrode through supply of high-frequency electric power to the metal terminal. At least a portion of the inner surface of the axial bore is coated with metal coating. The center electrode and the metal terminal are in electrical contact with the metal coating.

Abstract: Separation of a noble metal tip is prevented and wear resistance is enhanced, while the increase in manufacturing cost is suppressed. A spark plug 1 includes a center electrode 5 and a noble metal tip 31. The center electrode 5 and the noble metal tip 31 are joined to each other through a molten portion 35. An area of an interface between the noble metal tip 31 and the center electrode 5 is set to be 5% or less with respect to a cross-sectional area of the noble metal tip 31 which is perpendicular to an axial line CL1 at a portion of an outer surface of the noble metal tip 31 which is nearest to the molten portion 35. In the cross section including the axial line CL1, supposing that a length of the portion of the molten portion 35 in the axial line CL1 which is exposed to the outer surface is A (mm), and a width of the noble metal tip 31 is B (mm), B/A?6 is satisfied. The portion of the molten portion 35, of which a length along the axial line CL1 is A/1.

Abstract: There is provided according to the present invention a manufacturing method of a spark plug that includes a cylindrical metal shell, a cylindrical ceramic insulator retained in the metal shell, a center electrode retained in the ceramic insulator and extending in an axial direction and a ground electrode having a rear end portion fixed to the metal shell and a front end portion formed with a protruding region facing a front end portion of the center electrode with a gap left therebetween and being of substantially uniform thickness except for an area where the protrusion is formed. The spark plug manufacturing method includes a press forming step for pressing the whole of a ground electrode material for constituting the ground electrode, so as to form a protruding region on a front end portion of the ground electrode material and a welding step for, after the press forming step, welding a rear end portion of the ground electrode material to the metal shell.

Abstract: An ignition system wherein creation of misfires is suppressed and excellent ignition ability is realized. The ignition system includes a spark plug; a discharge power source applying a voltage in order to generate a spark discharge at the spark plug; an AC power source supplying AC power to a spark generated by the spark discharge; and an ignition cable electrically connecting the spark plug, the discharge power source and the AC power source. The ignition cable includes a discharge electrode connecting the discharge power source and the spark plug, an AC electrode transmitting AC power from the AC power source to the spark plug, and an insulator interposed between the discharge and AC electrodes.

Abstract: Peeling resistance of a noble metal chip is improved by reducing a difference in the thermal stress generated between the noble metal chip and a ground electrode. A spark plug 1 includes an insulator 2, a center electrode 5, a metal shell 3, and a ground electrode 27, wherein a spark discharge gap 33 is formed between the center electrode 5 and the noble metal chip 41 bonded to the ground electrode 27. The ground electrode 27 is provided with a concave hole portion 43, and 70% or more of the noble metal chip 41 is bonded to the hole portion 43 of the ground electrode 27 through a fusion portion 35 formed by fusing the noble metal chip and the ground electrode 27 to each other by emitting a laser beam or the like from the side surface of the noble metal chip. A gap 45 is formed between the noble metal chip 41 and at least a part of an inner wall surface 43 S of the hole portion 43 so as to be more than 0 mm and equal to or less than 1.