Abstract: A spark plug and manufacturing method. The spark plug (1) includes a metallic shell (3) extending along an axis CL1, a ceramic insulator (2), a center electrode (5), and a ground electrode (27) having a base end portion joined to a front end face (26) of the metallic shell (3). The method includes assembling the metallic shell (3) and a center electrode assembly (41); and joining the ground electrode (27) to the front end face (26). The distance between a reference plane SP perpendicular to the axis CL1 and the front end face (26) as measured along the axis CL1 varies in the circumferential direction. In the joining step, the position of the distal end portion of the ground electrode (27) relative to the front end portion of the center electrode assembly (41) along the axis CL1 is adjusted by changing the region of the front end face (26) to which the ground electrode (27) is joined.

Abstract: A spark ignition device has a ceramic insulator surrounded by a metal shell. The metal shell extends along a longitudinal axis to a distal end. A center electrode is received in the ceramic insulator and extends along the longitudinal axis. A ground electrode has an attachment end fixed by a weld joint to the distal end of the shell and a free end extending from the distal end to provide a spark gap. The weld joint includes a capacitive pulse discharge weld joint and a laser weld joint, which in combination inhibit material expulsion; provide a reliable, strong attachment of the ground electrode to the shell; provide an improved heat transfer path between the ground electrode and the shell, and facilitate repeatable and accurate positioning of the ground electrode to the shell. The weld joint includes a homogeneous mixture of the metal shell and the ground electrode.

Abstract: A spark plug including a ceramic insulator having an axial hole, a center electrode inserted into the axial hole, a metallic shell provided around the insulator, a ground electrode fixed to the metallic shell, and a tip joined to a distal end portion of the ground electrode and forming a spark discharge gap between the tip and a forward end portion of the center electrode. The ground electrode includes an outer layer and an inner layer provided inside the outer layer and formed of a metal containing copper as a main component. The tip is joined to the ground electrode by a fusion portion containing a metal forming the tip and a metal forming the outer layer. The fusion portion is in contact with the inner layer and contains copper. The spark plug efficiently conducts heat from the tip to the inner layer to improve corrosion resistance of the tip.

Abstract: The invention relates to a spark plug for a gas-fired internal combustion engine, and Includes a metallic body, with an insulator fastened in the body. A central electrode, leads through the insulator and includes a protruding end of a precious metal alloy. An annular ground electrode is fastened to the body and surrounds the end of the central electrode which, at the inside thereof facing the central electrode is provided with a precious metal or with a precious metal alloy. The mutually facing surfaces of the central electrode and ground electrode formed by the precious metal or the precious metal alloy are coaxially disposed cylinder surfaces. A cap is provided and attached to the body and which, after installation of the spark plug into a combustion chamber of the internal combustion engine, shields the central electrode and the ground electrode from the combustion chamber.

Abstract: Described is a spark plug for gasoline engines with an elongated hollow body made of metal, said body having a forward end with an undercut formed by an interior annular shoulder of the body and a rear end, with an elongated ceramic insulator which is mounted in the body and has a rear end that projects beyond the rear end of the body and has a forward end beyond which the forward end of the body projects, with a center electrode which is inserted into the insulator, projects beyond the forward end thereof, and is connected to a metal connection pin in an electrically conductive manner, said connection pin projecting beyond the rear end of the insulator, and with at least one ground electrode which starts from the forward end of the body and is approached to the center electrode to an electrode distance (EA) to form a spark gap.

Abstract: A method of making an electrode material for use in a spark plug and other ignition devices including industrial plugs, aviation igniters, glow plugs, or any other device that is used to ignite an air/fuel mixture in an engine. The electrode material is a ruthenium-based material that includes a “fibrous” grain structure. The disclosed method includes hot-forming a ruthenium-based material into an elongated wire that includes the “fibrous” grain structure while intermittently annealing the ruthenium-based material as needed. The intermittent annealing is performed at a temperature that maintains the “fibrous” grain structure.

Abstract: A corona igniter (20) includes a metal shell (32) with a corona reducing lip (38) spaced from an insulator (26) and being free of sharp edges (40) to prevent arcing (42) in a rollover region and concentrate the electrical field at an electrode firing end (48). The corona reducing lip (38) includes lip outer surfaces (88) being round, convex, concave, or curving continuously with smooth transitions (90) therebetween. The corona reducing lip (38) includes lip outer surfaces (88) presenting spherical lip radii (r1) being at least 0.004 inches. The corona igniter (20) also includes shell inner surfaces (104) and insulator outer surfaces (75) facing one another being free of sharp edges (40).

Abstract: A spark plug includes a center electrode, an insulator, a metallic shell, and a ground electrode which has a noble metal tip at the other end portion. A gap is formed between a forward end portion of the center electrode and a discharge surface of the noble metal tip. When an acute angle formed by the forward end surface and the discharge surface is ?1, a point on the forward end surface closest to the noble metal tip is A, opposite ends of the discharge surface are B1 and B2, and an angle formed by a first line segment connecting A and B1 and a second line segment connecting A and B2 is ?2, 35°??1?55°, 85°??2?90°, and the difference in length between the first and second line segments is equal to or less than 10% of the longer line segment.

Abstract: A spark plug has a metal shell and a ground electrode joined at a base end portion thereof to the metal shell and includes a surface layer and a core higher in thermal conductivity than the surface layer. The surface layer has a thickness of 0.2 to 0.4 mm at a specific position that is located 1 mm from the base end portion. The spark plug satisfies the following condition: W1?W2×1.55?(W3+0.25) where W1 (mm) is a width of the metal shell at a weld region of the metal shell joined with the base end portion in a specific direction that extends perpendicular to the axis direction through a center line of the ground electrode; W2 (mm) is a thickness of the ground electrode at the specific position in the specific direction; and W3 (mm) is a thickness of the surface layer at the specific position in the specific direction.

Abstract: A spark plug for an internal combustion engine is provided, which includes a housing, an insulation porcelain, a center electrode and a ground electrode. At least one of a tip portion of the center electrode and an opposing portion of the ground electrode is provided with a projection portion. At least one of the projection portions has a cross section perpendicular to the axial direction of the plug, the cross section having a minimum curvature radius portion and being in a specific shape that satisfies a predetermined requirement. The requirement is that, when a first straight line, a first line segment and a second straight line are provided, and when the cross section is divided into a first region and a second region by the second straight line, the second region has an area larger than the area of the first region.

Abstract: An ignition plug that promotes expansion of flame and enhances spark corrosion resistance, said plug includes a center electrode; a tubular insulator holding the center electrode; a tubular metallic shell holding the insulator; and a ground electrode having a bent portion and a facing end surface. A plurality of peak voltages can be applied to the center electrode after application of a voltage for trigger discharge thereto. When a forward end surface of the center electrode and the facing end surface are projected onto a plane orthogonal to axial direction of the center electrode, the projection of the center of the forward end surface and the projection of the facing end surface overlap with each other, and the projection of a remote-side edge portion of the facing end surface which is located on the side remote from the bent portion is located within the projection of the forward end surface.

Abstract: An ignition plug having enhanced seal performance, while suppressing deformation of a metallic shell thereof. The ignition plug includes a metallic shell having a crimp portion, a male screw portion, a seat portion, and a bent portion. The bent portion has a largest outer diameter (OD) portion, and first and second smallest OD portions, wherein 0.01?(L2+L3?L1)/(L2+L3)?0.3 is satisfied. L1 is distance between a point in the first smallest OD portion farthest from center axis and a point in the second smallest OD portion farthest from center axis, L2 is distance between the point in the first smallest OD portion farthest from center axis and a point in the largest OD portion farthest from center axis, and L3 is distance between the point in the second smallest OD portion farthest from center axis and the point in the largest OD portion farthest from center axis.

Abstract: A spark plug having an insulator that can be restrained from cracking in an environment of heating and cooling cycles. The spark plug includes an insulator having an axial bore extending in the direction of the axis, and a center electrode held in one end portion of the axial bore. The center electrode has an outer layer, and a core provided within the outer layer and formed from a material higher in thermal conductivity than the outer layer. After a heat treatment, the outer layer has a high-hardness region having a hardness of 190 Hv or higher and a thickness of 30 ?m to 200 ?m, and an element supply region having a thickness of 50 ?m or more.

Abstract: A spark plug for an internal combustion engine, including: a center electrode having a first noble metal pin of a first diameter mounted thereon, and a ground electrode having a second noble metal pin of a second diameter mounted thereon, the noble metal pins of the center electrode and of the ground electrode being mutually opposed at the end faces thereof; and the first diameter of the first noble metal pin of the center electrode being larger than the second diameter of the second noble metal pin of the ground electrode.

Abstract: A spark plug (20) for being threaded into a cylinder head (28) includes a shell (24) with threads (26) disposed at a predetermined angled relative to the ground electrode (34). The position of the threads (26) relative to the ground electrode (34) places the ground electrode (34) in a predetermined position in the combustion chamber (22) and relative to components of the engine, thus allowing the ground electrode (34) to provide a robust and reliable ignition. The threads (26) are formed by a thread forming apparatus (102) that includes an orientation tool (38) to position the ground electrode (34) relative to a thread forming apparatus (102), allowing the thread forming apparatus (102) to form the threads (26) at the desired angle (?).

Abstract: A spark plug including a center electrode and a ground electrode having a core portion and an outer layer covering the core portion, the core portion being formed from a material having a thermal conductivity higher than that of the outer layer. At least a portion in which thickness of the outer layer is 0.5 mm or less is present at a cross-section perpendicular to a direction in which the ground electrode is extended. Further, the composition of the electrode material forming the outer layer is as follows: Ni is 96 mass % or more, total of at least one kind selected from Y and rare earth elements is 0.05 mass % or more, Al is 0.5 mass % or less, and Si is 0.5 mass % or more and 1.5 mass % or less, where the total of Ni, Y, rare earth elements, Al, Si does not exceed 100 mass %.

Abstract: An igniter for igniting a fuel-air-mixture in a combustion chamber, in particular in a combustion engine with one or several combustion chambers, by generating a high frequency corona discharge, said ignitiger comprising an assembly comprising an ignition electrode, an outer conductor surrounding the ignition electrode, which has a front end and a rear end, and an electrical insulator arranged between the ignition electrode and the outer conductor, wherein the ignition electrode is part of an electrical high-frequency resonant circuit, protrudes over the front end of the outer conductor, and is connected to an alternate current source or alternate voltage source which feeds the HF-resonant circuit, and delivers a high frequency alternate current or a high frequency alternate voltage, respectively. The ignition electrode is branched into more than four electrode branches extending away from the outer conductor, in different directions.

Abstract: A spark plug having an integral gasoline combustion sensor is disclosed. The spark plug includes a center electrode assembly with a terminal stud at one end and a center electrode with a sparking surface at an opposite end; a generally tubular insulator surrounding the center electrode assembly; a shell surrounding the insulator and having along its length a turn-over on a first end, a barrel having an outer surface and barrel shoulder on a gasket flange thereof, a threaded portion, and a ground electrode; and a piezo sensor assembly located on the barrel shoulder proximate the outer surface of the barrel which includes a lower electrode contact, a piezo transducer, an upper electrode contact, an isolator having a convex upper surface, and an upper bushing which is attached to the barrel.

Abstract: A spark plug includes a body and a center electrode. The body includes a first end, a second end, an insulating portion and a shell portion. The shell portion includes an exterior threaded section, a nut section below the threaded section, an electrically conductive, axially elongated firing ring above the threaded section and terminating at an upper surface. The center electrode extends through the body and includes a terminal end and a firing end. The firing end extends beyond the second end of the body and includes a plurality of tines. Each tine includes a first section and a second section. The first section extends radially from the firing end. The second section extends axially toward the upper surface of the firing ring and terminates at a tip. The insulating portion electrically isolates the shell portion from the center electrode.

Abstract: A spark plug includes at least one of a center electrode or a ground electrode that is produced by the steps of: mixing a matrix metal with carbon so that the carbon content of the resultant mixture is adjusted to 80 vol. % or less; subjecting the mixture to powder compacting or sintering, to thereby form a core; placing the core in a cup formed of nickel or a metal containing nickel as a main component; and subjecting the cup to cold working. The thus-produced electrode exhibits favorable thermal conductivity and good heat dissipation, by virtue of the small difference in thermal expansion coefficient between the core and an outer shell. The spark plug including the above electrode exhibits excellent durability.

Abstract: A spark plug superior in salt corrosion resistance and stress corrosion cracking resistance is provided. The spark plug includes a metallic shell coated with a composite layer which includes a nickel plating layer and a chromate layer formed on the nickel plating layer. The spark plug is characterized in that the nickel plating layer has a thickness A which satisfies a relational expression 3 ?m?A?15 ?m and that the chromate layer has a thickness B which satisfies a relational expression 2 nm?B?45 nm.

Abstract: A high efficiency spark plug operative to produce negligible waste materials discharge from the combustion engine with high power output and low fuel consumption. The spark plug has an upper chamber formed by an annular partition ring mounted at an upper position of the cylindrical cavity located in the lower portion of the shell of the spark plug. A cylindrical sleeve mounted in the cavity and located below the annular partition ring. A horizontal annular shoulder in the cylindrical sleeve extending in a horizontal position and separating the interior of the cylindrical sleeve into a middle chamber and a lower chamber. The annular shoulder formed the grounding electrode with an edge of its inner opening located in a spaced manner from the spark tip of the central electrode.

Abstract: A spark ignition device, metal shell, and methods of construction are provided. The spark ignition device has a ceramic insulator extending along a longitudinal axis and a metal shell. The metal shell extends along the longitudinal axis to a distal end. A center electrode is received in the ceramic insulator and extends along the longitudinal axis. A ground electrode has an attachment end fixed by a weld joint to the distal end of the shell and a free end extending from the distal end to provide a spark gap. The weld joint includes a resistance weld joint and a laser weld joint, which in combination inhibit material expulsion; provide a reliable, strong attachment of the ground electrode to the shell; provide an improved heat transfer path between the ground electrode and the shell, and facilitate repeatable and accurate positioning of the ground electrode to the shell.

Abstract: A spark plug includes: a center electrode, a ground electrode, which is side-mounted on the center electrode, and a noble metal insert, which is situated on the center electrode. The noble metal insert is situated in a cutout provided in a base material of the center electrode and connected in a continuous material to the base material of the center electrode. The noble metal insert is directed with one surface towards the side-mounted ground electrode.

Abstract: A lateral transverse discharge spark plug (10) which consists of a cylindrical metallic shell (20) having a tubular ceramic insulator (22), including an insulator attachment end (28) enclosed therein. An offset center electrode (30) is surrounded by the ceramic insulator. The offset center electrode has a firing tip (36) extending from the insulator distal end. A ground electrode 38 is attached to a side of the metallic shell, and the ground electrode has a first gap (#1GAP) distanced from the offset center electrode. The offset center electrode and the ground electrode protrude from the cylindrical metallic shell attachment end and the end of said ceramic insulator in a terminally aligned orientation. A second embodiment utilizing a center electrode (31) is also disclosed.

Abstract: An ignition plug (1) includes a center electrode (5) extending in the direction of an axis (CL1), an insulator (2) having an axial hole (4) into which the center electrode (5) is inserted, a tip (31) joined to a forward end portion of the center electrode (5) by a fusion portion (35), and a ground electrode (27) forming a gap (33) in cooperation with the tip (31). The ignition plug generates high-frequency plasma at the gap (33) when high-frequency electric power is supplied to the gap (33). The forward end of the tip (31) is located forward of the forward end of the insulator (2) with respect to the direction of the axis (CL1). Also, at least a portion of the outer surface of the fusion portion (35) is located within the axial hole (4), and, the distance between a forward-end-side opening of the axial hole (4) and the rearmost end of the outer surface of the fusion portion (35), measured along the axis (CL1), is equal to or greater than 0.1 mm.

Abstract: A spark plug, including a central electrode, a first ground electrode, which is situated in a curved shape having a horizontal area and an essentially vertical area, and at least one second ground electrode, which is situated adjacent to the central electrode in such a way that a distance between the first ground electrode and the central electrode is less than a distance between the second ground electrode and the central electrode.

Abstract: A spark plug for an internal combustion engine is provided which is equipped with an inward top end protrusion. The inward top end protrusion extends inwardly from a top end of a cylindrical housing within which a porcelain insulator is disposed. The porcelain insulator has a center electrode disposed therein. The inward top end protrusion is at least partially located to be closer to the top of the spark plug than a top end of the porcelain insulator is in an axial direction of the spark plug. This enhances the strength of an electric field surrounding the center electrode, which facilitates the ease with which an electron is emitted by the center electrode and thus permits an initial required voltage at the spark plug to be decreased, thereby resulting in an increase in service life of the spark plug.

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: 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 includes a ceramic insulator, a center electrode, a metallic shell, and a ground electrode. The center electrode has a shoulder portion at a forward end portion, which tapers forward with respect to the axial direction. A noble metal tip is joined to the forward end portion of the center electrode through a fusion zone. A spark discharge gap is formed between the noble metal tip and the ground electrode. The shortest distance between the fusion zone and a forward end surface of the noble metal tip is 0.8-1.2 mm. The outside diameter of the fusion zone as measured at a forward end of the fusion zone is smaller than that as measured at a rear end of the fusion zone. An acute angle ?1 formed by a straight line L1 and a straight line L2 satisfies the relational expression ?1?72°.

Abstract: A spark plug has a metal shell, an insulator, a center electrode, and a ground electrode. One or more firing tips can be attached to the center electrode, to the ground electrode, or to both electrodes. The metal shell and ground electrode are attached together by way of one or more laser keyhole welds at an interface of the shell and electrode. Before the laser keyhole welds, resistance welding can be executed for a temporary attachment.

Abstract: A spark plug having a metal shell, an insulator, a center electrode, a ground electrode, and a multi-layer sparking component. The multi-layer sparking component is attached at a firing end of the ground electrode and includes a thin precious metal layer formed overtop a base metal layer and, according to some embodiments, overhangs the end of the ground electrode. The precious metal and base metal layers may be pre-manufactured together as a bi-metal ribbon, sheet or laminate before the multi-layer sparking component is attached to the ground electrode.

Abstract: A spark plug for an internal combustion engine is provided, which includes a housing, an insulation porcelain, a center electrode and a ground electrode. At least one of a tip portion of the center electrode and an opposing portion of the ground electrode is provided with a projection portion. At least one of the projection portions has a cross section perpendicular to the axial direction of the plug, the cross section having a minimum curvature radius portion and being in a specific shape that satisfies a predetermined requirement. The requirement is that, when a first straight line, a first line segment and a second straight line are provided, and when the cross section is divided into a first region and a second region by the second straight line, the second region has an area larger than the area of the first region.

Abstract: A spark plug including a ceramic insulator having an axial hole, a center electrode inserted into the axial hole, a metallic shell provided around the insulator, a ground electrode fixed to the metallic shell, and a tip joined to a distal end portion of the ground electrode and forming a spark discharge gap between the tip and a forward end portion of the center electrode. The ground electrode includes an outer layer and an inner layer provided inside the outer layer and formed of a metal containing copper as a main component. The tip is joined to the ground electrode by a fusion portion containing a metal forming the tip and a metal forming the outer layer. The fusion portion is in contact with the inner layer and contains copper. The spark plug efficiently conducts heat from the tip to the inner layer to improve corrosion resistance of the tip.

Abstract: A method of manufacturing a spark plug that includes a metallic shell, an insulator, a center electrode, a ground electrode, and a firing pad. The method may include the steps of: applying a first laser beam to attach the firing pad to the ground electrode, and then using a second laser beam from the same laser beam welder to attach the ground electrode to the metallic shell. The laser beam welder may include a high energy density fiber laser for forming key-hole laser welds, as well as a programmable focusing optic (PFO) assembly for redirecting laser beams from one welding site to the other.

Abstract: A method of manufacturing an electrode material for use in spark plugs and other ignition devices. The electrode material may be manufactured into a desirable form by hot-forming a layered structure that includes a ruthenium-based material core, an iridium-based interlayer disposed over an exterior surface of the ruthenium-based material core, and a nickel-based cladding disposed over an exterior surface of the iridium-based material interlayer. The elongated layered wire produced by the hot-forming then has its nickel-based cladding removed to derive an elongated electrode material wire that includes the ruthenium-based material core encased in the iridium-based material. The elongated electrode material wire can be used to make many different spark plug/ignition device components.

Abstract: A high efficiency spark plug operative to produce negligible waste materials discharge from the combustion engine with high power output and low fuel consumption. The spark plug has an upper chamber formed by an annular partition ring mounted at an upper position of the cylindrical cavity located in the lower portion of the shell of the spark plug. A cylindrical sleeve mounted in the cavity and located below the annular partition ring. A horizontal annular shoulder in the cylindrical sleeve extending in a horizontal position and separating the interior of the cylindrical sleeve into a middle chamber and a lower chamber. The annular shoulder formed the grounding electrode with an edge of its inner opening located in a spaced manner from the spark tip of the central electrode.

Abstract: A spark plug including a housing as a ground contact to an internal combustion engine, a center electrode situated in the housing along a center axis of the spark plug, an insulator between the center electrode and the housing, and a two-legged ground electrode whose legs are located on the combustion chamber side of the center electrode and angled with respect to one another in a leg plane which is perpendicular to the center axis, the two ends of the ground electrode being connected to the housing respectively by one connection point, a first gap between one end of the housing on the combustion chamber side and the leg plane being smaller than or equal to a second gap between one of the connection points and the center axis, and/or the ground electrode being tapered toward the center axis.

Abstract: A spark plug for use with internal combustion engines includes a metallic shell housing having a semi-cylindrical shroud partially surrounding the insulator and the center electrode and to which the ground electrode is joined. The semi-cylindrical shroud promotes improved heat dissipation from the ground electrode to the shell housing.

Abstract: A spark plug having a center electrode, a ground electrode, and a ground electrode side tip. The tip partially projects from a front end face and an inner circumference-side side surface of the ground electrode. The ground electrode has a center of the front end face. The center is located at a front end side in a direction of the axis with respect to a front end of the center electrode. L/X?1.28 is satisfied, where L (mm) represents a length of the ground electrode along a central axis of the ground electrode and X (mm) represents a projection length of the ground electrode relative to a metallic shell. 8.

Abstract: A capacitive discharge welding method is used to join firing tips, such as those made from various precious metals, to spark plug electrodes. In one embodiment, charged capacitors or other energy storage devices coupled to welding electrodes quickly release stored energy so that a peak weld power and maximum interface temperature is quickly established, followed by a rapid decline in weld power and interface temperature. The resulting capacitive discharge weld joint may include solidified molten material from both the firing tip and the electrode and possess a number of other desirable qualities.

Abstract: A spark plug (20) includes a center electrode (24) and a ground electrode (22). The electrodes (22, 24) include a core (26) formed of a copper (Cu) alloy and a clad (28) formed of a nickel (Ni) alloy enrobing the core (26). The Cu alloy includes Cu in an amount of at least 98.5 weight percent, and at least one of Zr and Cr in an amount of at least 0.05 weight percent. The Cu alloy includes a matrix of the Cu and precipitates of the Zr and Cu dispersed in the Cu matrix. The Ni alloy of the clad (28) includes Ni in an amount of at least 90.0 weight percent. The Ni alloy also includes at least one of a Group 3 element, a Group 4 element, a Group 13 element, chromium (Cr), silicon (Si), and manganese (Mn) in a total amount sufficient to affect the strength of the Ni alloy.

Abstract: An electrode core material that may be used in electrodes of spark plugs and other ignition devices to provide increased thermal conductivity to the electrodes. The electrode core material is a precipitate-strengthened copper alloy and includes precipitates dispersed within a copper (Cu) matrix such that the electrode core material has a multi-phase microstructure. In several exemplary embodiments, the precipitates include: particles of iron (Fe) and phosphorous, particles of beryllium, or particles of nickel and silicon.

Abstract: A spark plug includes a center electrode having an end portion, and an earth electrode having an opposing portion opposed to the end portion via a gap. The end portion has an end-projecting portion. The opposing portion has an opposing-projecting portion opposed to the end-projecting portion. The end-projecting portion and the opposing-projecting portion have non-projection direction opposing surfaces which are parallel to and opposed to each other with a minimum distance and in a direction other than a projection direction. A first opposing area of a portion which includes the non-projection direction opposing surfaces and where the end-projecting portion and the opposing-projecting portion are opposed to each other with the minimum distance is larger than a second opposing area obtained when a plane of the end-projecting portion and a plane of the opposing-projecting portion, which are orthogonal to the projection direction, are opposed to each other in the projection direction.

Abstract: A spark plug includes a tubular insulator, a center electrode, a tubular metal shell, a ground electrode, and a pillar body tip. The tubular insulator has an axial hole penetrating in the direction of an axis. The pillar body tip includes one end face that is welded to the ground electrode and another end face that forms a gap with a front end portion of the center electrode. The ground electrode includes a part where the tip is to be welded. The surface forms a clearance with a part including a constituent material of the tip. The ground electrode includes a surface where a plating layer is disposed. The plating layer covers a surface excluding a formation part of the clearance. The clearance has a size A that is equal to or more than 0.01 mm and equal to or less than 0.5 mm.

Abstract: A buried portion (32B) buried from a junction target surface of a ground electrode (27) is provided in a noble metal tip (32). In a section, perpendicular to a central axis CL2 of the ground electrode (27), a large width portion (32W) is formed in the buried portion (32B), and a region between the junction target surface and a largest width region of the large width portion (32W) is formed into a shape which gradually increases in width, or into a shape having a region of the relevant shape and a constant width region. A region from the large width portion (32W) to a point of intersection P1, P2 is covered with a base material of the ground electrode (27) and a melt portion (35), and a thickness t1 (mm) of the noble metal tip (32) and a buried amount t2 (mm) satisfy 0.25?t2/t1.

Abstract: A spark plug includes a center electrode and a ground electrode. The center electrode is arranged relative to the ground electrode in such a way that the spark gap extends between the ground electrode and the center electrode. The spark gap is surrounded by a wall, wherein the wall has a recess or hole, which is designed in such a way that a feeler gauge can be inserted between the center electrode and the ground electrode.

Abstract: A spark plug having a center electrode; a ground electrode provided so as to form a gap between the ground electrode and the center electrode; and a tip provided on at least one of a distal end portion of the ground electrode and a front end portion of the center electrode, the end portions facing each other, characterized in that the tip contains an element group M (M consists of at least one species of Pt and Rh) in an amount of 3 mass % to 35 mass %, and an element group L (L consists of at least one species of Ir, Ru, and Pd) in an amount of 0 mass % to 15 mass %; the total amount of the element group M and the element group L is at most 35 mass %; and the total amount of Ni, the element group M, and the element group L is at least 94 mass %.

Abstract: A spark plug and a method of forming the same. The spark plug having a rod-shaped center electrode extending in an axial direction, a tubular insulator having an axial hole and holding the center electrode in the axial hole, a tubular metallic shell having an end surface, an inner circumferential surface, and a gap formed between the inner circumferential surface and a forward end portion of the insulator, and a ground electrode welded to the end surface. A method of manufacturing the spark plug includes a welding step of welding the ground electrode to the end surface; and a shaping step which is performed after the welding step so as to form the inner circumferential surface, through shaping, on the metallic shell having the ground electrode welded to the end surface thereof.