Abstract: An ignition plug includes an insulator having an axial bore extending in the direction of an axis and an electrode inserted into the axial bore, and generates plasma discharge through supply, to the electrode, of high-frequency power generated by a predetermined high-frequency power supply. The electrode includes a center electrode inserted into the forward side of the axial bore and a terminal electrode inserted into the rear side of the axial bore. In the axial bore, the terminal electrode and the center electrode are fixed to the insulator by means of a glass seal which contains a glass component, and are in direct contact with each other. Thus, ignition performance can be further improved.

Abstract: A ground electrode includes a main body portion and a projecting portion having a width smaller than a width of the main body portion. A spark discharge gap is formed between a discharging surface of the projecting portion and a front end surface of a center electrode. When the front end surface and the ground electrode are projected on a first plane, at least a part of the projection region of the projecting portion overlaps the projection region of the front end surface. A width Le (mm), a width Lc (mm), a cross-sectional area Sg (mm2), a cross-sectional area Sc (mm2), an angle ?1 (°), an angle ?2 (°), an angle ?3 (°), and an angle ?4 (°) satisfy expressions Le<Lc, 2.9?Sc+Sg?4.25, and 0.30?(?1/?2)×(?3/?4)?0.67.

Abstract: A ground electrode includes a main body portion and a projecting portion having a width smaller than a width of the main body portion. A spark discharge gap is formed between a discharging surface of the projecting portion and a front end surface of a center electrode. When the front end surface and the ground electrode are projected on a first plane, at least a part of the projection region of the projecting portion overlaps the projection region of the front end surface. A width Le (mm), a width Lc (mm), a cross-sectional area Sg (mm2), a cross-sectional area Sc (mm2), an angle ?1(°), an angle ?2(°), an angle ?3(°), and an angle ?4(°) satisfy expressions Le<Lc, 2.9?Sc+Sg?4.25, and 0.30?(?1/?2)×(?3/?4)?0.67.

Abstract: An ignition plug that reliably restrains generation of corona discharge for enhancing accuracy in detection of ionic current and method of manufacturing same. The ignition plug is configured such that a metallic shell and an insulator are fixed together by means of a crimped portion provided at a rear end portion of the metallic shell and bent radially inward. An electrically insulative filling member fills a space formed between the crimped portion and the insulator. The filling member covers at least a portion of an outer circumferential surface of a rear trunk portion of the insulator along the entire circumference and the entirety of a rear end surface of the metallic shell, which is a portion of the outer surface of the crimped portion and is visible from the rear side with respect to the direction of an axial line CL1.

Abstract: A spark plug has a center electrode having an electrode base member and a core material which is disposed in the electrode base member and which predominantly contains copper, and a noble metal tip disposed at a forward end of the center electrode, and a fusion portion formed between the noble metal tip, and the electrode base member and the core material. The fusion portion is in contact with the core material in a cross section which is parallel to the center axis of the center electrode and which passes through the center axis and the fusion portion. The fusion portion contains a component of the noble metal tip, a component of the electrode base member, and a copper component forming the core material.

Abstract: An ignition system that sufficiently utilizes the energy output from a power supply, to thereby realize excellent ignition performance. The ignition system includes an ignition plug having a spark discharge gap formed between a center electrode and a ground electrode, and a power supply for supplying electric energy to the spark discharge gap. Electric energy output from the power supply for producing spark discharge of one unit is set to 100 mJ or greater. S1?[{?30 (mm?1)×G1+60}/100]×S2 and G1<2.0 are satisfied wherein G1 represents the size (mm) of the spark discharge, S1 represents an area (mm2) defined with a region obtained by removing, from a projection region of the center electrode, a region where the projection region overlaps with a projection region of the ground electrode and S2 represents an area (mm2) defined with the projection region of the center electrode.

Abstract: An ignition plug that reliably restrains generation of corona discharge for enhancing accuracy in detection of ionic current and method of manufacturing same. The ignition plug is configured such that a metallic shell and an insulator are fixed together by means of a crimped portion provided at a rear end portion of the metallic shell and bent radially inward. An electrically insulative filling member fills a space formed between the crimped portion and the insulator. The filling member covers at least a portion of an outer circumferential surface of a rear trunk portion of the insulator along the entire circumference and the entirety of a rear end surface of the metallic shell, which is a portion of the outer surface of the crimped portion and is visible from the rear side with respect to the direction of an axial line CL1.

Abstract: A spark plug has a center electrode having an electrode base member and a core material which is disposed in the electrode base member and which predominantly contains copper, and a noble metal tip disposed at a forward end of the center electrode, and a fusion portion formed between the noble metal tip, and the electrode base member and the core material. The fusion portion is in contact with the core material in a cross section which is parallel to the center axis of the center electrode and which passes through the center axis and the fusion portion. The fusion portion contains a component of the noble metal tip, a component of the electrode base member, and a copper component forming the core material.

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: An ignition plug includes an insulator having an axial bore extending in the direction of an axis and an electrode inserted into the axial bore, and generates plasma discharge through supply, to the electrode, of high-frequency power generated by a predetermined high-frequency power supply. The electrode includes a center electrode inserted into the forward side of the axial bore and a terminal electrode inserted into the rear side of the axial bore. In the axial bore, the terminal electrode and the center electrode are fixed to the insulator by means of a glass seal which contains a glass component, and are in direct contact with each other. Thus, ignition performance can be further improved.

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 plasma ignition device 20 includes a spark plug 100, a DC power supply 210, an AC power supply 220, and a coupling section 300. The coupling section 300 includes a capacitor 320 which electrically connects the AC power supply 220 to the spark plug 100. The coupling section 300 reduces the capacitance of the capacitor 320 in the second ignition mode in which transmission of AC power is halted, as compared with that in the first ignition mode in which AC power is transmitted to the spark plug 100.

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: 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: 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: 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: A glow plug includes a heater member; heater power lead wires which extend rearward along an axis and whose conductors electrically communicate with one and of a heater conductor for supply of power; a sensor, portion for detecting the combustion pressure of an internal combustion engine; a sensor connection line connected to the sensor portion and extending rearward along the axis; a housing; a sensor-portion-enclosing tube; and a grommet formed from an insulating rubber-like elastic material, having insertion holes through which the heater power lead wires and the sensor connection line are respectively inserted, the grommet liquid-tightly closing an end portion of the sensor-portion-enclosing tube and liquid-tightly holding the heater power lead wires and the sensor connection line.

Abstract: A glow plug includes a heater member; heater power lead wires which extend rearward along an axis and whose conductors electrically communicate with one and of a heater conductor for supply of power; a sensor, portion for detecting the combustion pressure of an internal combustion engine; a sensor connection line connected to the sensor portion and extending rearward along the axis; a housing; a sensor-portion-enclosing tube; and a grommet formed from an insulating rubber-like elastic material., having insertion holes through which the heater power lead wires and the sensor connection line are respectively inserted, the grommet liquid-tightly closing an end portion of the sensor-portion-enclosing tube and liquid-tightly holding the heater power lead wires and the sensor connection line.

Abstract: To provide a combustion pressure sensor capable of reducing noises generated by the force in a rocking direction by making uniform the stress exerted onto the piezoelectric element; and a glow plug having the same.