Abstract: An ammonia gas sensor including a reference electrode (320) is formed on the back surface of a solid electrolyte member (310), and a detection electrode (335) is formed on the front surface of the solid electrolyte member (310). A detection lead (350) is provided on the front surface of the solid electrolyte member (310) such that the detection lead (350) is connected to the detection electrode (335). An insulating layer (340), (380) is provided between the detection lead (350) and the solid electrolyte member (310), or on the detection lead (350).

Abstract: To provide a spark plug in which separation of a tip can be prevented and enough wear resistance can be obtained without increasing the content of nickel in the tip portion, and a use method of the spark plug. In a spark plug (100) including an outside electrode (10) including an electrode body portion (11) and a tip (12) bonded to the electrode body portion (11), and a center electrode (20), and the tip (12) is opposed to the front end portion of the center electrode (20) through a spark discharge gap (G), the electrode body portion (11) is made of a nickel alloy containing 13 to 18% by mass of Cr, 0.03 to 0.08% by mass of C, 1 to 3.5% by mass of Mo, 0 to 0.8% by mass of Si, Al, Mn and Ti, and 68% by mass or more of Ni, and the tip (12) is made of a platinum alloy containing 0 to 4% by mass of Ni.

Abstract: A soot detecting apparatus includes: a high voltage generating unit for generating a high voltage; a discharge sensor which includes a pair of electrodes to be, disposed in an atmosphere to be detected, for causing a spark discharge at a discharge voltage dependent upon soot concentration in the atmosphere when the high voltage is applied across the pair of electrodes; a first detection unit for detecting a first discharge voltage value when the spark discharge occurs in the discharge sensor upon application of the high voltage of a predetermined voltage polarity; a first output unit for determining a first soot concentration value based on the first discharge voltage value; and a changeover unit for converting the predetermined voltage polarity to an opposite voltage polarity for causing reverse spark discharge at the pair of electrodes of the discharge sensor.

Abstract: An object of the invention is to provide a spark plug having a discharge portion made of a precious metal tip, in which peeling of the precious metal tip from a surface of the discharge portion can be suppressed while spark abrasion, oxidation abrasion and abnormal abrasion of the discharge portion can be suppressed.

Abstract: A method for producing a spark plug, the spark plug including: a center electrode; an insulator which holds the center electrode therein in a state where a tip end portion of the center electrode protrudes therefrom; a metal shell which holds the insulator therein; a ground electrode which is fixed to the metal shell, the ground electrode having an inner side face having a width that is smaller as it advances toward a tip end side, in a portion of the inner side face positioned between a pair of tapered faces; and a discharge portion which is bonded to the inner side face of the ground electrode by laser welding so as to attain a diameter of 0.8 mm or less and a height of 0.5 mm or more, a discharge gap being formed between the discharge portion and the tip end portion of said center electrode, the method including: forming the tapered faces before the discharge portion is laser-welded to the inner side face.

Abstract: A method for producing a spark plug, the spark plug including: a center electrode; an insulator which holds the center electrode therein in a state where a tip end portion of the center electrode protrudes therefrom; a metal shell which holds the insulator therein; a ground electrode which is fixed to the metal shell, the ground electrode having an inner side face having a width that is smaller as it advances toward a tip end side, in a portion of the inner side face positioned between a pair of tapered faces; and a discharge portion which is bonded to the inner side face of the ground electrode by laser welding so as to attain a diameter of 0.8 mm or less and a height of 0.5 mm or more, a discharge gap being formed between the discharge portion and the tip end portion of said center electrode, the method including: forming the tapered faces before the discharge portion is laser-welded to the inner side face.

Abstract: A spark plug including: a cylindrical metal shell; a cylindrical insulator fixed to the metal shell; a center electrode having its leading end protruding from a leading end of the insulator and its trailing end fixed to the insulator; and a ground electrode having one end fixed to the metal shell and forming a discharge gap between the ground electrode and the center electrode. The ground electrode includes a precious metal alloy portion containing: 50 weight % or more of a first component of one of Rh and Pt; less than 50 weight % of a second component of the other of Rh and Pt; and optionally a third component containing at least one of: Ni in an amount of less than 7 weight %; and Zr in an amount of less than 2 weight % the content of the third component being less than that of the second component.

Abstract: An object of the invention is to provide a higher-durability spark plug provided with a center electrode and a side electrode. At least one of the center electrode and the side electrode includes a precious metal member facing a spark discharge gap between the electrodes. A sweating phenomenon of the precious metal member can be suppressed while spark abrasion, oxidation abrasion and abnormal abrasion of the precious metal member are suppressed. The precious metal member contains Ir as a main component, and smaller amounts of Rh, Ru, and Ni.

Abstract: A spark plug including: a center electrode as defined herein; a substantially cylindrical insulator as defined herein; a cylindrical metal shell as defined herein; and a ground electrode as defined herein, wherein a spark discharge gap is provided between the leading end portion of the center electrode and the leading end portion of the ground electrode, and the ground electrode has a bulging curved face on a side opposite to a side in which the center electrode is provided, and a maximum of width of the ground electrode within a range of ±1 mm from a center point of the spark discharge gap in the axial direction, as viewed in a direction where the center electrode and the ground electrode overlap, is 105% or less of a width of an ordinary portion having a substantially constant width.

Abstract: A spark plug 100 comprised of a metal shell 1, an insulator 2, a center electrode 3 and a ground electrode 4. A rear-end face of the ground electrode 4 is welded to a front-end face of the metal shell 1, and a bent portion 5 located at the intermediated position in the longitudinal direction is bent toward the center of the spark plug 100. The ground electrode 4 assumes a circular-shape with a diameter of 2 mm or less whereby an inflow of an air-fuel mixture is not disturbed even when the air-fuel mixture directly flows into a back face of the ground electrode 4. The ground electrode 4 is comprised of an outer layer 4A made of a nickel alloy and an inner layer 4B made of pure copper with an excellent thermal conductivity, in which a ratio of a cross-sectional area of the inner layer 4B to the entire cross-sectional area of the ground electrode 4 is 10% or more to 35% or less.

Abstract: A spark plug for an internal-combustion engine is provided wherein the central and ground electrodes exhibit a long service life and wherein the fatigue strength at high temperatures is improved. The ground electrode is made from an alloy comprised of nickel (Ni) as a primary component, chromium: 20-30% by weight, iron: 7-20% by weight, aluminum: 1-3% by weight, titanium: 0.05-0.5% by weight, manganese: not higher than 0.1% by weight, silicon: not higher than 0.1% by weight, and carbon: not higher than 0.5% by weight. The alloy further includes at least one specific element selected from zirconium, yttrium, neodymium, cerium, lanthanum and samarium. Further, the total content of the specific element group is 5% or more of the aluminum content and is not higher than 1% by weight.

Abstract: A plasma jet spark plug provides improved ignitability and durability by forming a part of a spark discharge gap outside the electric discharge space which generates plasma. An ignition system for the plasma jet spark plug is also disclosed. The plasma jet spark plug includes a center electrode, an insulator defining an axial bore which partially surrounds the center electrode, a cavity surrounded by an inner circumferential face of the axial bore which extends from an opening portion of a front end of the axial bore of the insulator and wherein a front end face of the center electrode is formed. A ground electrode is bent towards a front end portion of the insulator.

Abstract: There is provided a method for controlling a plasma-jet spark plug in a four-stroke internal combustion engine, including the steps of: causing the spark plug to generate a primary discharge during either a compression stroke or an expansion stroke of the engine in such a manner as to produce a plasma by the primary discharge; and causing the spark plug to generate a secondary discharge during a time after the primary discharge and before the completion of a subsequent intake stroke of the engine.

Abstract: A spark plug comprising: a center electrode extending in a direction of an axis of said spark plug; a cylindrical insulator which has a shaft hole, and which holds said center electrode in said shaft hole in a state where a tip end of said center electrode is projected from a tip end face of said insulator; a metal shell which holds said insulator; and a ground electrode in which one end is joined to a tip end face of said metal shell, and which extends from said one end toward another end, wherein said ground electrode has an inner side face which faces said center electrode, and an outer side face which is a back face with respect to said inner side face, said outer side face is formed as an arcuately curved face when viewed from a side of said another end in an extending direction of said ground electrode, and a columnar noble metal tip is joined to said inner side face.

Abstract: A spark plug including an insulator having an axial hole in an axial direction; and a center electrode disposed in a tip end side of the axial hole of the insulator so as to project a tip end of the center electrode from the tip end side of the insulator. The center electrode includes an electrode base member made of pure Ni or an Ni alloy containing 85 wt % or more of Ni; and a noble metal chip fixed to a tip end of the electrode base. The spark plug further includes a metal shell surrounding the insulator; and a ground electrode in which one end is joined to the metal shell, and another end portion opposes the noble metal chip to form a spark discharge gap between the ground electrode and noble metal chip, wherein M, D1, and D2 as defined herein satisfy M?10.1 mm, 0.5 mm?D2<1.4 mm, and D1/D2?3.5.

Abstract: In a wire drawing process for forming a wire rod containing iridium as a main component and which further contains nickel and at least one of platinum, rhodium and ruthenium, and having a cross-sectional area of not smaller than 0.05 mm2 and not larger than 1.2 mm2. The worked material is continuously heated red hot and/or white hot in a heating region 103 extending up to 60 mm from the work inserting surface 101a of a die 101 in a direction opposite that in which the work 102 moves, the work being heated to a temperature of 1000 to 1150° C. at a temperature measuring position 105 which is removed from the work inserting surface 101a by 20 mm. Furthermore, the temperature in the region 106 extending from the temperature measuring position 105 to the work inserting surface 101a is set to not lower than 1000° C., and the wire drawing rate is set to 300 to 1600 mm/min.

Abstract: In a glow plug and a spark plug, the surface of a main metal shell is coated with a chromate film in which the quantity of trivalent chrome is 95 wt % or more of the contained chrome components and which has a thickness of 0.2 ?m to 0.5 ?m.

Abstract: An object of the invention is to provide a spark plug having a discharge portion made of a precious metal tip, in which peeling of the precious metal tip from a surface of the discharge portion can be suppressed while spark abrasion, oxidation abrasion and abnormal abrasion of the discharge portion can be suppressed.

Abstract: An object of the invention is to provide a higher-durability spark plug provided with a center electrode and a side electrode to form a spark discharge gap between the center electrode and the side electrode, at least one of the center electrode and the side electrode including a precious metal member facing the spark discharge gap, in which a sweating phenomenon of the precious metal member can be suppressed while spark abrasion, oxidation abrasion and abnormal abrasion of the precious metal member can be suppressed. In the invention, the spark plug (100) comprises a center electrode (3), and a side electrode (4) located on one side of the center electrode (3) so that a spark discharge gap (G) is formed between the center electrode (3) and the side electrode (4). The center electrode (3) and the side electrode (4) include first and second precious metal tips (33) and (43) respectively.

Abstract: A spark plug including: a cylindrical metal shell; a cylindrical insulator fixed to the metal shell; a center electrode having its leading end protruding from a leading end of the insulator and its trailing end fixed to the insulator, and a ground electrode having one end fixed to the metal shell and forming a discharge gap between the ground electrode and the center electrode. The ground electrode includes a precious metal alloy portion containing: 50 weight % or more of a first component of one of Rh and Pt; less than 50 weight % of a second component of the other of Rh and Pt; and optionally a third component containing at least one of: Ni in an amount of less than 7 weight %; and Zr in an amount of less than 2 weight % the content of the third component being less than that of the second component.