Abstract: To excellently grow flame kernel while lowering breakdown voltage, a bypass electrode comprising a semiconductor material is installed in a path bypassing an inductive spark gap between a center electrode and a ground electrode, and the center electrode and the ground electrode are electrically connected by the bypass electrode and capacitive discharge is carried out by applying breakdown voltage between the center electrode and the ground electrode via the bypass electrode, and thereafter, inductive discharge is carried out through the inductive spark gap.

Abstract: The invention provides a spark plug having an insulator which is composed mainly of alumina, and which is more superior in voltage endurance characteristics at high temperatures as compared with the prior-art materials. An insulator 2 of a spark plug 100 is made of an insulating material which is composed mainly of alumina, and which contains Al component within a range of 95 to 99.7 wt % in weight converted to Al2O3, and in which an area ratio occupied by alumina base principal-phase particles with particle size not less than 20 &mgr;m is not less than 50% as a cross-sectional structure of the insulator is observed. By making the alumina base principal-phase particles appropriately coarse like this, the voltage endurance characteristics of the insulator can be remarkably improved.

Abstract: In a spark plug, a main gap is formed between the center electrode and the ground electrode, and an auxiliary gap is formed between the center electrode and a projecting inner edge formed at an open end portion of the metallic shell. The inner wall surface of the metallic shell extending from a terraced portion toward the tip end of the metallic shell is tapered such that the diameter of the inner wall surface decreases toward the tip end of the metallic shell by an amount of 0.6 mm or more. Through reduction of a gas volume defined by the insulator and the inner wall surface of the metallic shell, entry of high temperature combustion gas can be reduced to thereby decrease a thermal load imposed on the insulator, while entry of carbon can be minimized to thereby prevent contamination. Accordingly, heat resistance and contamination resistance can be significantly improved, and thus the range of operation of the spark plug can be widened.

Abstract: In a semi-creeping discharge type spark plug, a cylindrical metal shell and an insulator are provided, the latter of which has an axial bore and placed within the metal shell so that a front end of the insulator extends beyond the metal shell. A center electrode is placed within the axial bore of the insulator so that a front end surface edge of the center electrode retracts by 0.1˜0.6 mm behind from a front end surface of the insulator. A ground electrode, one end of which is connected to a front end of the metal shell, and the other end of which is bent to oppose an outer surface of the insulator so as to form an air-gap therebetween while permitting creeping spark discharges running along said front end surface of said insulator. A foward edge portion of a front end surface of the ground electrode extends by 0.0˜1.0 mm forward from the front end surface of the insulator.

Abstract: A spark plug includes a center electrode, an insulator provided outside the center electrode, a metallic shell provided outside the insulator, a ground electrode disposed to oppose the center electrode, and a spark discharge portion fixed on at least one of the center electrode and the ground electrode for defining a spark discharge gap. The spark discharge portion is formed from an alloy containing Ir as a main component, Rh in an amount of 0.2 to 10 wt. %, and Pt in an amount not greater than 10 wt. %. The ratio WPt/WRh of the Pt content to the Rh content falls within the range of 0.1-1.5.

Abstract: A spark plug with a plug screw outer diameter D of 10 mm-12 mm, wherein the length A of the discharge gap 6, the width B of the gas volume 7, the protruding length C of the insulator 2 with respect to the fitting piece 1, the diameter F of the center electrode 3, the end diameter G of the noble metal tip 51 and the protruding height H of the noble metal tip 51 with respect to the center electrode 3 are within the following ranges:0.9 mm.ltoreq.A.ltoreq.1.35 mm, (10/9)A.ltoreq.B, 1.0 mm.ltoreq.C.ltoreq.2.5 mm, 10 mm.ltoreq.D.ltoreq.12 mm, 2.0 mm.ltoreq.F.ltoreq.2.7 mm, 0.6 mm.ltoreq.G.ltoreq.0.9 mm, and 0.3 mm.ltoreq.H.ltoreq.1.0 mm.

Abstract: A spark plug has a central electrode, an insulator, a metal shell and a ground electrode. The insulator is provided exterior to the central electrode. The metal shell is provided exterior to the insulator. The ground electrode opposes the central electrode. At least one of the central electrode and the ground electrode has a multi-layered structure comprising a core and a high heat conducting layer that covers at least part of the outermost surface of the core. An inner layer of the core is more heat conductive than the outermost layer of the core that is in contact with high heat conducting layer.

Abstract: In a spark plug, a cylindrical metal shell (1) is provided whose inner wall has a rear section and a front section to respectively serve as a diameter-increased section and a diameter-decreased section with a seat portion (1) as a boundary therebetween. An insulator (2) is fixedly placed within the metal shell (1) so that a front end surface (21) of the insulator (2) extends beyond a front end surface (12) of the metal shell (1) with a shoulder portion (231) of an insulator nose (23) engaged against the seat portion (11) of the metal shell (1) by way of a packing (10). A center electrode (3) is fixedly placed within an axial bore (22) of the insulator (2), A ground electrode (4) is connected to the front end surface (12) of the metal shell (1), and bent so that a front end surface (41) of the ground electrode (4) opposes an outer surface (311) of the center electrode (3).

Abstract: A spark plug includes a center electrode, an insulator provided outside the center electrode, a metallic shell provided outside the insulator, a ground electrode disposed to oppose the center electrode, and a spark discharge portion fixed on at least one of the center electrode and the ground electrode for defining a spark discharge gap. The spark discharge portion of the spark plug is formed of a metallic material containing Ir as a main component, and a region where the Vickers hardness is not greater than Hv 400 extends from the surface of the spark discharge portion to a depth of 0.05 mm or more. The average value of d.sub.min /d.sub.max ratios of grains on an arbitrary cross-section is preferably equal to or greater than 0.7 where d.sub.min represents the minimum diameter of each grain on the cross-section and d.sub.max represents the maximum diameter of the grain. The ratio of hS/hB is preferably not greater than 0.

Abstract: A spark plug is described incorporating a metal hydride in one of its electrodes thereby being able to generate plasma or ionization in the spark gap for ignition of the fuel mixture in the engine.

Abstract: A threaded portion is formed on a metal shell of a spark plug. Within a mounting base of the metal shell, a pressure sensor is arranged in such a direction that it generates an electrical signal in response to a variation in a tightening load of the spark plug. A slit is formed as a pressure-introducing channel along an axis of the spark plug in the threaded portion of the metal shell so that the slit is communicated with an interior of the mounting base.

Abstract: In a spark plug for use for an internal combustion engine, an elongated insulator is provided in which a center electrode is supported. A cylindrical metal shell is provided in which the insulator is supported, and a ground electrode extends from the metal shell to form a spark gap with a front end of the center electrode. The front end of the center electrode has a tapered-off step section whose front end surface has a spark erosion resistant portion, and having a boundary between a columnar portion of the center electrode and the tapered-off step section. The boundary of the tapered-off step section is located within a front end surface of the insulator, and a front end surface of the tapered-off step section is positioned outside of the front end surface of the insulator.

Abstract: A spark plug is provided having a center electrode disposed in a metallic shell through an insulator so that the front end of the center electrode forms a spark gap with an outer electrode. A platinum tip is secured to the outer electrode positioned to oppose the front end of the center electrode. The outer electrode is provided with a heat-conductive core metal cladded with a matrix metal which is made of a nickel-based alloy containing 10-20 wt. % chromium. The platinum tip is welded to the outer electrode to form a welded portion between the platinum tip and the outer electrode and the platinum tip is positioned to terminate slightly short of the core metal so that the distance between a circumferential edge of the welded portion and a front end of the core metal is in the range 0.0 mm-2.0 mm measured lengthwise along direction the outer electrode.

Abstract: A spark plug having the electrodes composed of twisted stainless steel wire with their spark gap ends frayed so as to give more spark contacting area, reduce heat and eliminate wear on the electrodes, thus giving a stronger, more efficient spark and more efficient combustion of the fuel-air mixture in the cylinders. A sealing means is also incorporated in the interior of the plug to prevent escape of any combustion products. The frayed ends will vibrate during the firing cycle, which will shake off any carbon which may tend to accumulate on them. A modification shows the ends of the wires not frayed but solid and clean cut.

Abstract: In a spark plug including a cylindrical metal shell whose inner wall has a ledge portion, an insulator having a seat portion which engages with a rear slope surface of the ledge portion to be supported within the metal shell, a center electrode supported with an axial bore of the insulator, and a ground electrode extended from the metal shell to form a spark gap with the center electrode. A dimensional relationship among (A), (B) and (g) is defined as follows: {(B-A)/2}.gtoreq.0.8.times.(g) or {(B-A)/2}.gtoreq.0.9.times.(g). Where B (mm) is an inner diameter of a metal shell portion which surrounds an insulator nose, A (mm) is a base diameter of the insulator nose, and g (mm) is a width dimension of the spark gap.

Abstract: A spark plug for an internal combustion engine comprising: a cylindrical metal tube; a rod-shaped central electrode within the cylindrical metal tube; a tubular insulator within which the rod-shaped central electrode is located, wherein the tubular insulator is arranged substantially centrally in and substantially coaxially with the cylindrical metal tube; and at least two ground electrodes affixed to the cylindrical metal tube, wherein the at least two ground electrodes are each bent toward the metal electrode, wherein each ground electrode together with the central electrode forms a different member of a set of spark paths comprising: (i) an air sliding spark path, (ii) and air-air sliding spark path and (iii) an air spark path.

Abstract: Spark plug has a central electrode, an insulator provided exterior to the central electrode, main metallic shell provided exterior to the insulator in such a way that the central electrode protrudes from one end, and a ground electrode coupled at one end to the main metallic shell and which has the other end disposed to face the central electrode 3, with a chip being secured to either the central electrode or the ground electrode or both to form spark discharge gap g. The chip is made of a metal based on Ir which contains Rh in an amount ranging from 3 to 50 wt % (50 wt % being not inclusive).

Abstract: In a spark plug, a tubular insulator has an axial bore in which a center electrode and a terminal electrode are axially aligned, the terminal electrode having a seal portion fixedly supported by partly filling the axial bore with a glass sealant. The insulator further has a tapered shoulder portion between a diameter-reduced portion and a diameter-increased portion, each provided on the insulator. A metallic shell is placed around the diameter-increased portion of the insulator, a rear end of the metallic shell being caulked against the diameter-reduced portion of the insulator, a space between the metallic shell and the diameter-reduced portion of the insulator being filled with a ceramic powder. An inclination of the tapered shoulder portion of the insulator ranges from 10 to 45 degrees against a plane perpendicular to the terminal electrode. A roulette is formed on an outer surface of the seal portion of the terminal electrode in which the glass sealant is filled.

Abstract: A spark plug with improved wear resistance includes an outer conductive housing, a ceramic insulator positioned within the housing, and a central electrode inside the insulator. One or more ring-shaped auxiliary electrodes are positioned on the ceramic insulator between the central electrode and the outer conductive housing. The one or more ring-shaped auxiliary electrodes have a central portion and peripheral edges which are thickened with respect to the central portion. The spark plug provides a spark gap between the central electrode and the auxiliary electrode and between the auxiliary electrode and the conductive housing.

Abstract: An improved spark plug having multiple ground electrodes (10) placed around a center electrode (12). Standing vertical ground electrodes are joined at top base of a metal jacket (18). Ground electrodes (10) and center electrode (12) are made of a rigid material.

Abstract: A spark plug for internal combustion engines is provided with a ground electrode in the form of a metallic bar the end of which is facing the central electrode at an appropriate distance. The cross section of the bar is triangular or ogival with a rounded tip directed outwardly. The bar terminates in an outwardly tapered end face.

Abstract: In a spark plug which has an electrode metal made from a heat- and erosion-resistant nickel alloy whose front end has a noble metal tip made of iridium or ruthenium, the electrode metal has a thermal conductivity of at least 30 W/m.multidot.K so as to avoid rapid temperature rise in the noble metal tip to thereby minimize oxidation-evaporation and attendant wear thereof.

Abstract: A spark plug for use in an internal combustion engine comprises a central electrode made of a base metal and an earth electrode. A tip portion is provided on the central electrode. The tip portion includes a noble metal tip layer for defining a spark discharge gap between the noble metal tip layer and the earth electrode, and an alloy layer provided between the noble metal tip layer and the central electrode. The tip portion is provided with grooves to be divided into a plurality of sections. The tip portion has an outer peripheral wall flared towards the earth electrode, and a width of the grooves gradually increases from a bottom thereof to a surface of the noble metal tip layer for defining the shark discharge gap.

Abstract: A spark plug which realizes reliability against thermal stress even in a case where dissimilar noble metal materials are disposed on the tip portion of the center electrode opposing the ground electrode and which realizes improved productivity while assuring durable reliability. The spark plug includes a center electrode electrically insulated from a housing and having a small-diameter portion at a tip portion which has a diameter smaller than that of a main body of the center electrode and composed of similar kinds of material as the center electrode, and a round-shape material, which is formed into a cylindrical or a ring shape, composed of dissimilar metal material.

Abstract: A precombustion chamber ignition device for preferably lean fuel-air mixtures and having a precombustion chamber. This precombustion chamber contains a electrode carrier extending into the precombustion chamber and on it at least one ignition electrode is attached, which has at least one ignition portion, which cooperates with a internal wall surface of the precombustion chamber in defining at least one spark gap extending substantially athwart the longitudinal axis of the precombustion chamber. In this respect the internal wall surface acts as a ground electrode. The ignition portion of the at least one ignition electrode is offset in relation to the longitudinal axis of the precombustion chamber and is arranged essentially parallel to the wall surface, which is substantially cylindrical in the spark gap portion, of the precombustion chamber close to the wall surface.

Abstract: According to the present invention, a spark plug for an internal combustion engine includes a center electrode, a ground electrode so as to form a spark gap with the center electrode, and a tip electrode composed of a material having a superior consumable resistance as compared to the center electrode and disposed on an end face of the center electrode so as to form a spark gap with the ground electrode. An axial length of the discharge portion of the ground electrode where spark discharge occurs is substantially larger than an axial length of the tip electrode where spark discharge occurs. When used for an internal combustion engine, a spark discharge is mainly generated between the peripheral surface of the center electrode and the ground electrode during early operation. Consequently, as the center electrode has been consumed, the spark discharge is mainly generated between the tip electrode and the ground electrode.

Abstract: A spark discharge tip, such as for a spark plug for an internal combustion engine in which the life of the tip is prolonged. A composite material is formed by bonding a material for a discharge layer, mainly composed of platinum, to a material for a thermal stress relieving layer, which is an alloy mainly composed of platinum, and having a coefficient of thermal expansion between that of the electrode and that of the discharge layer. A composite tip is formed by stamping the composite material into a columnar shape from the discharge layer side so that the periphery of the interface between the discharge layer and stress relieving layer is covered by the discharge layer. The composite tip is then resistance welded to the electrode.

Abstract: A composite chip formed by joining a discharging layer and a heat stress relieving layer at a joint interface therebetween beforehand is provided on at least one of a central electrode and a ground electrode in its discharge portion made of an electrode material. The discharging layer is made of a precious metal or a precious metal alloy having superior spark- and wear-resistance, and the heat stress relieving layer is made of a metal or an alloy having a linear expansion coefficient between those of the discharging layer and the electrode material. Formed at the joint interface between both the discharging layer and the heat stress relieving layer through mutual diffusion of those materials developed when the two layers are joined to each other is a diffusion layer, in which concentrations of materials of both the layers are continuously changed. A thickness of the diffusion layer is not less than 3 .mu.m in a state that the composite chip is welded to the discharge portion.

Abstract: In spark ignited engine configurations, it is common to provide a spark plug that has a spark gap that has dimension that will accommodate good starting capabilities for the engine. In some cases, this spark gap is larger than required for the engine to run efficiently, especially at high loads. As a result, the voltage required to bridge the gap when the engine is running at high loads is much higher than necessary and causes erosion of the electrode and a build up of deposits on the ground strap. Ultimately, this greatly reduces the life of the spark plug. The present invention provides a spark plug that utilizes an adjusting means that is connected to the electrode of the spark plug and functions to move the electrode with respect to the ground strap to adjust the gap therebetween. The adjusting means is responsive to the temperature of the spark plug which will vary with engine loads or an increase in pressure within the combustion chamber.

Abstract: In an electrode for a spark plug, an elongated blank metal is made of a nickel-based alloy and including a front surface. A firing tip is provided from a slug made of a noble metal, the slug being concentrically placed on the front surface of the elongated blank metal and laser beam welded to thermally melt the entire slug and thereby produce a thermal weld, so that the front surface of the elongated blank metal is partly fused together with the slug to form a melted portion with the front surface and the slug so as to contain the front surface within the melted portion in the range of 0.5 wt % to 80.0 wt %.

Abstract: A spark plug for an internal combustion engine is provided with a fine wire platinum firing tip. The platinum tip is preformed in a rivet before being welded to the center electrode during manufacture of the spark plug.

Abstract: In a spark plug electrode in which an alloyed tip is secured to a firing end of one of opposed electrodes forming a spark gap therebetween, the tip has a spark-erosion resistant noble metal component, and the noble metal component varies as a weight percentage of the alloyed tip in an axial direction of the electrode depending on a magnitude of spark discharges to which a specified portion of the tip is subjected between the opposed electrodes, wherein a largest weight percentage of the noble metal component is provided at areas on the electrode subjected to relatively high magnitude spark discharges, and wherein a smallest weight percentage of the noble metal component is provided at areas on the electrode subjected to relatively low magnitude spark discharges.

Abstract: There is disclosed a spark plug which can maintain a low spark voltage for a long period of time even if a noble metal tip is used in a small amount. A discharge gap is formed between a central electrode and an earth electrode. The noble metal tip is formed on that end face of the central electrode facing the earth electrode. A cross-shaped groove is formed in that end face of the noble metal tip joined to the central electrode. The cross-shaped groove is exposed when the noble metal tip is consumed by a discharge developing in the discharge gap.

Abstract: An igniter for a propane burner is made substantially impermeable to moisture by coating the porous ceramic igniter shell with at least one layer of an inorganic, nonmetallic coating, the coating being an alkali silicate formed from dehydrating liquid water-glass on the surface of the ceramic igniter shell.

Abstract: The present invention provides an improved spark plug and electrode arrangement therefor. A central electrode has a sparking end adjacently positioned to and mated with a spark-receiving end of an outer electrode. At least one of the electrode ends has a protrusion extending towards the other electrode, and the other electrode has a geometrically mated indentation. A relatively uniform spark gap having increased surface area is provided therebetween. Hemispherical or rounded and conical protrusions and mated indentations are preferred embodiments of the present invention. The present spark plug electrode arrangement provides increased area sparks, regulates sparks under varied conditions and decreases incidence of carbon build up.

Abstract: In a center electrode for a spark plug, the center electrode is made of a heat-conductor core cladded with a nickel-alloyed metal. A recess is provided on the front end surface of the nickel-alloyed matrix and the columnar tip is made of a precious metal and fit in the recess in such a manner that a front end of the tip protracts from the recess. The outer surface of the tip is welded to an inner surface of the recess. The dimensional relationship of the components of the spark plug A, B, C, D, E, F and G is as follows: 0.3 mm.ltoreq.A.ltoreq.0.8 mm, 1.2A.ltoreq.B.ltoreq.3A, 0.1 mm.ltoreq.(C-A)/2.ltoreq.0.5 mm, D.ltoreq.(C-A)/2, E.ltoreq.B/4, 0 mm.ltoreq.F.ltoreq.0.5 mm and A/5.ltoreq.G.ltoreq.

Abstract: Disclosed is a spark plug for an internal combustion engine including an annular end portion with a central electrode having an end within the annular end portion. A ground electrode extends from the annular end portion and has a portion extending over and spaced a predetermined distance above the end of the central electrode. The improvement comprises the end of the central electrode having cross-grooves therein defining four end faces and the ground electrode having diverging prongs at its end over the central electrode, a portion of each prong being over two adjacent end faces of the central electrode. Improved ignition is provided without critical manufacturing problems of prior art spark plugs.

Abstract: A spark plug for an internal combustion engine includes a metallic shell within which a tubular insulator is placed, a center electrode is provided within the insulator to form a spark gap between a front end of the center electrode and an outer electrode extending from the metallic shell. First and second stepped portions are provided near a front portion of the center electrode to form a clearance between an outer wall of the center electrode and an inner wall of the insulator. The stepped portions have a progressively decreasing diameter toward the front end of the center electrode. A tapered portion is provided at an inner wall of the insulator by bevelling a front open end of the insulator. This maintains high insulation of the insulator with significantly low carbon deposit, thus avoiding ignition failure of the spark plug.

Abstract: In an outer electrode, a rear end of which is securely connected to a metallic shell of a spark plug by means of welding to form a spark gap between a front end of the outer electrode and a firing tip of a center electrode which is concentrically placed within the metallic shell through an insulator, a middle core which is provided which is made of copper, and the middle core is clad by a heat and spark-erosion resistant metal. A centermost core is clad by the middle core. The centermost core is made of a similar metal to the metallic shell, and rear end of the centermost core is welded to the metallic shell so as to reinforce a welding portion between the metallic shell and the outer electrode.

Abstract: A spark plug for use in an internal combustion engine comprises a central electrode made of a base metal and an earth electrode. A tip portion is provided on the central electrode. The tip portion includes a noble metal tip layer for defining a spark discharge gap between the noble metal tip layer and the earth electrode, and an alloy layer provided between the noble metal tip layer and the central electrode. The tip portion is provided with grooves to be divided into a plurality of sections. The tip portion has an outer peripheral wall flared towards the earth electrode, and a width of the grooves gradually increases from a bottom thereof to a surface of the noble metal tip layer for defining the spark discharge gap.

Abstract: A spark plug for an internal combustion engine includes a central electrode, and an earth electrode disposed in opposed relation to the central electrode on an axis of the central electrode to thereby form a spark gap between the central electrode and the earth electrode. The central electrode has a pillar-like portion provided at a distal end thereof disposed close to the spark gap, the pillar-like portion having a predetermined thickness corresponding to an intended lifetime of the spark plug. The central electrode also has a smaller-diameter portion disposed adjacent to a proximal end of the pillar-like portion, the smaller-diameter portion being smaller in diameter than the pillar-like portion. The pillar-like portion and the smaller-diameter portion are interconnected in a step-like manner. A step portion may be provided between the pillar-like portion and the smaller-diameter portion so as to limit the position of a spark discharge.

Abstract: A spark plug for an automotive internal combustion engine providing improved ignition even when carbon is deposited on the insulator of the plug. A rich fuel-air ratio causes carbon to be deposited on spark plug insulators, thereby decreasing its effective insulation. By limiting the geometrical dimension of the plug's center electrode the problem of carbon build-up is overcome. The sizes of these elements have certain allowable ranges that enhance the igniting effect of the plug.

Abstract: In a spark plug having a cylindrical metallic shell a front end of which is extended into a combustion chamber of an internal combustion engine, an insulator is provided within the metallic shell so as to provide an annular clearance between a front end of the metallic shell and that of the insulator, a width of the annular clearance being within a range of 0.65 mm .+-.0.25 mm. An extension skirt which the metallic shell is extended into the combustion chamber has a length within a range from 1.0 mm to 3.0 mm. A tapered surface is provided by planing off an inner edge of a front end of the metallic shell, and the surface angularly falls within angles from 20 to 40 degrees. One end of an outer electrode is welded to the tapered surface while other end of the outer electrode is bent to oppose a front end of a center electrode.

Abstract: A spark plug is disclosed having a metal body 18, a center electrode 16 and an insulator 14 surrounding the center electrode, the part of the insulator disposed within the combustion chamber being separated by an annular gap from the metal body of the spark plug. In order to reduce cycle to cycle variations, a filler 12 of very poor thermal conductivity is used to fill the gap between the insulator 14 and the body 18 to prevent gas movement in this gap, thereby preventing the gap from forming part of the combustion chamber.

Abstract: The center electrode of an ignition plug is a unitary cylindrical tungsten rod in which the outer peripheral portion thereof has a higher work function than the core portion.

Abstract: In a spark plug for use in an internal combustion engine, a nickel-alloy based center electrode is placed into a metallic shell through a tubular insulator. An outer electrode is depended from the metallic shell to from a spark gap with a front end of the center electrode. A spark portion is secured to the center electrode, and comprising a nickel-alloy based tubular clad tip and an iridium or iridium-alloy based inner core fit into the clad tip. A rear open end of the clad tip is welded to a front end surface of the center electrode. A dimensional relationship among the center electrode, the inner core and the clad tip being determined as follows: A.ltoreq.1.5mm, 0.2mm.ltoreq.B.ltoreq.0.8mm, C.gtoreq.0.1mm, where A is an outer diameter of the front end surface of the center electrode, B is an outer diameter of the inner core, while C is an outer diameter of the tubular clad tip.

Abstract: A spark plug for use in an internal combustion engine having a insulator with a cylindrical body that surrounds a center electrode. The cylindrical body has a first diameter section separated from a second diameter section by a shoulder. A sleeve that surrounds the second diameter has an integral base that is positioned a fixed distance from the tip of the center electrode by the engagement of a flange on the sleeve with shoulder on the cylindrical body. A radial tab that extends from the sleeve is located in a slot in a head on a combustion chamber of an internal combustion engine to establish the position of a ground electrode defined by the base in the combustion chamber. An end nut that surrounds the first diameter and engages the flange to locate and position the spark plug within the combustion chamber.

Abstract: A rapid heat-dissipating type spark plug has a metallic shell which is made of material having a tensile stress of more than 40 Kg/mm.sup.2 with a thermal conductivity of more than 60 W/m.multidot.k.In another embodiment, there is provided a ground electrode which is made of nickel or nickel alloy.The ground electrode is connected to the metallic shell through a metallic ring which is made of different metal from the metallic shell such as steel, stainless steel or nickel alloy.

Abstract: Disclosed are two types of ignition plugs for use in internal combustion engines of automobiles and the like, which are essentially characterized by the addition of ignition means to conventionally paired center and ground electrodes, and their location to the latters; that is, both the ignition plugs are designed to ignite gas mixture in the whole space of combustion chamber by firstly igniting gas mixture in an ignition groove on the ignition means; for this, the opening of the groove is located in such a place as to receive first ignition seeds appearing in a spark gap between center and ground electrodes as effectively as possible.

Abstract: A spark plug for an internal combustion engine including a center electrode, an earth electrode, a metal tip joined by welding to an ignition section of at least one of the center electrode and the earth electrode, and an alloy layer located at a welding portion between the metal tip and the at least one electrode. The metal tip is formed of material highly resistant to heat and wear which is distinct in the coefficient of thermal expansion from the material of the electrodes. The alloy layer is formed to have a thickness of at least about 10.mu., so as to avoid the rupture of the metal tip along the surface thereof adjacent to the welding portion.