Abstract: A prechamber spark plug having a thermally enhanced prechamber cap with a thermally conductive core, such as one made from a copper-, aluminum- and/or silver-based material. Due to its location and function, a prechamber cap is exposed to thermal energy from a pre-combustion process taking place within a prechamber, as well as thermal energy from a combustion process taking place in a main combustion chamber. Thus, the prechamber cap is being heated on both its interior and its exterior and, if not sufficiently cooled, can become so hot that it undesirably triggers preignition events in the engine. The thermally enhanced prechamber cap may include a main body with an interior surface and an exterior surface, a thermally conductive core with one or more thermal segments and insert segments, and one or more openings extending between a prechamber and a main combustion chamber, where each opening extends through an insert segment that is designed to resistant to corrosion and/or erosion.

Abstract: A spark plug for an internal combustion engine includes a housing, an insulator, a center electrode, a ground electrode, and an auxiliary chamber forming portion. The ground electrode faces the center electrode from an outer peripheral side and forms a discharge gap between the ground electrode and the center electrode. An auxiliary chamber is formed inside the auxiliary chamber forming portion. A distance in an axial direction between the discharge gap and a distal end of the auxiliary chamber is equal to or greater than a maximum wall thickness of the auxiliary chamber forming portion. The auxiliary chamber forming portion includes injection holes. The injection holes are formed in a state where openings on an outer side are located closer to a distal end than openings on the auxiliary chamber side. At least one of the injection holes is an injection hole in the axial direction formed along an axial direction of a plug.

Abstract: A spark plug has an insulator having a through hole formed along an axial direction, a center electrode which is partially inserted into a portion of the through hole on a forward end side in the axial direction, and a glass seal portion which is in contact with the insulator and the center electrode within the through hole, in which the glass seal portion contains glass and an electrically conductive substance. The glass contains an Si component and a B component in a total amount of 50 mass % or more, as reduced to SiO2 and B2O3, a Zn component in an amount of 20 mass % to 35 mass % as reduced to ZnO, and an alkali metal component. The glass contains, as the alkali metal component, an Na component in an amount less than 1 mass % as reduced to Na2O.

Abstract: The spark plug includes: an insulator having an axial hole extending in an axial direction; a center electrode disposed at a front end in the axial direction of the axial hole and having a front end portion that protrudes from a front side of the axial hole; a tubular metal shell holding the insulator; and a ground electrode having one end portion that is fixed to a through hole provided in the metal shell, the ground electrode having another end portion that forms a discharge gap between the other end portion and the front end portion of the center electrode. The through hole extends toward the front side in the axial direction, in a direction from an outer peripheral surface toward an inner peripheral surface of the metal shell. The one end portion is located on a rear side relative to the other end portion in the axial direction.

Abstract: A spark plug including a center electrode; a metallic member forming a tubular shape around an axis of the spark plug, holding the center electrode therein, and having a hole formed in a side wall thereof and extending in a radial direction; and a ground electrode supported in the hole and extending from the hole toward the axis. The ground electrode has a fixing portion formed of metal and fixed to the hole, and an ignition portion containing a noble metal, disposed on a side toward the axis in relation to the fixing portion, and having a discharge surface for forming a gap between the ignition portion and the center electrode. The absolute value of the difference in coefficient of thermal expansion between the metallic member and the fixing portion is smaller than the absolute value of the difference in coefficient of thermal expansion between the metallic member and the ignition portion.

Abstract: A spark plug according to one embodiment of the present invention includes an insulator formed of an alumina-based sintered body, wherein the insulator contains 90 wt % or more of an aluminum component in terms of oxide, and wherein crystal grains of the insulator has an average grain size of 1.5 mm or smaller and a grain size standard deviation of 1.2 ?m or smaller.

Abstract: A spark plug wherein the occurrence of cracks at a joint portion between a cover portion and a metal shell in the spark plug is prevented. The spark plug includes a cylindrical metal shell that accommodates an insulator therein, and a cover portion that covers, from a front end side of the spark plug, a front end portion of a center electrode and a facing portion of a ground electrode to form a pre-chamber space. The cover portion is joined to a front end side of the metal shell and has injection holes that are through-holes. A first coefficient of thermal expansion A (10?5/K) of the material forming the cover portion at normal temperature and a second coefficient of thermal expansion B (10?5/K) of the metal shell at normal temperature satisfy a formula (1): A<B.

Abstract: A pre-chamber spark plug that includes a shell. Additionally, the pre-chamber spark plug includes an insulator disposed within the shell. In a particular embodiment, a center electrode has a first portion surrounded by the insulator, and a second portion that extends from the insulator into a pre-chamber. The pre-chamber defined by the shell. In a further embodiment, a ground electrode is attached to the insulator. In particular embodiments, the ground electrode is tubular in shape and includes an inner spark surface ring spaced in surrounding relation to the center electrode to create a spark gap, an outer ring attached to the shell, and a plurality of rounded spokes connecting the inner and outer rings. In a particular embodiment, the ground and center electrodes accommodate attachment of precious metal alloys to increase electrode surface life. In another embodiment the ground electrode and insulator is coaxial to the center electrode.

Abstract: A pressure detection signal processing device, engine control system, and non-transitory computer readable medium storing a program are provided. A current-voltage conversion part that converts a current signal corresponding to charge generated by a piezoelectric element in accordance with received pressure into a voltage signal, and digital signal processing parts that perform correction for removing a drift caused by a leakage current of the piezoelectric element on the voltage signal through digital signal processing are provided. The digital signal processing parts include a differentiation processing part that performs differentiation processing on the voltage signal, an integration processing part that performs integration processing on the signal having been subjected to the differentiation processing, and an integration processing part that further performs integration processing on the signal having been subjected to the integration processing.

Abstract: The spark plug includes an insulator made from an alumina-based sintered body, and the insulator contains 90 to 98 wt % of an Al component in oxide equivalent. The insulator contains 1 to 5 wt % of an Si component, 0.1 to 1 wt % of an Mg component, 2 wt % or less of a Ca component, 0.3 to 6 wt % of a Ba component, and 0.11 to 5 wt % of a rare earth component, in oxide equivalent. In analysis using a scanning transmission electron microscope with a probe diameter of an electron beam set at 1 nm, Si and a rare earth element are detected at a crystal grain boundary having a thickness of 15 nm or less, and an alkaline earth metal at the crystal grain boundary is less than a detection limit.

Abstract: A spark plug for an internal combustion engine, having a center electrode, which has a first body and a second body that is a precious metal welded to the first body and a ground electrode arranged roundabout the center electrode so that an annular ignition gap is formed between the electrodes. The second body of the center electrode is formed as an annular element having a central recess. The first body of the center electrode has a projection that extends into the recess of the second body. A first weld seam is formed between a radially outer surface of the projection of the first body and a radially inner surface of the second body delimiting the recess of the second body, and a second weld seam is formed between an axial surface of the main body of the first body and an axial surface of the second body.

Abstract: A method of producing a spark plug comprises (a) a step of combining a metallic shell and an insulator; (b) a step of inserting a portion of the assembly on its forward end side into a pressure container; (c) a step of bringing an insulating member into contact with the outer circumferential surface of a base side portion of the insulator over the entire circumference thereof, and pressing the assembly so as to close the opening by the assembly; and (d) a step of pressurizing the interior of the pressure container and applying a predetermined voltage between the terminal electrode and the metallic shell.

Abstract: A spark plug suppressor and a method of producing a spark plug suppressor from a suppressor precursor liquid that may be cured at a temperature below 300° C. The spark plug suppressor may include particles or grains dispersed in a matrix of electrically conducting material, electrically semiconducting material, or electrically non-conducting material. The suppressor may include a conductive glass seal component and a resistive suppressor component. The resistive suppressor component may be at least partially embedded in the glass seal component, and the glass seal component may seal a center electrode of the spark plug, a terminal of the spark plug, or both the center electrode and the terminal.

Abstract: A spark plug includes a tubular metal shell having a tapered portion that projects radially outward with respect to an external thread and is provided on a rear end side of the metal shell with respect to the external thread, a center electrode held in an insulated manner at a center of the metal shell on a front end side thereof, and a ground electrode connected to the metal shell to form a spark gap between the ground electrode and the center electrode. The tapered portion has a contact portion that contacts the inner surface of a plug hole formed in an engine when the external thread is tightened into a threaded hole in the plug hole. The Vickers hardness of the contact portion is higher than the Vickers hardness of at least a part of a portion between the contact portion and the external thread.

Abstract: A ceramic spark plug insulator with improved electrical and mechanical strength.

Abstract: A spark plug electrode having greater mechanical stability. The spark plug electrode includes a base body and a noble metal pin situated on the base body, the base body and the noble metal pin being connected to each other by a connection zone. The connection zone has at least one first welding seam and one second welding seam.

Abstract: Within a resin mold portion of a fuel injection valve, an amplifying member having a substrate is provided. An engagement hole that penetrates in an axial direction is formed in another end part of the amplifying member, and an engagement pin, which is formed on a bobbin of a housing, is inserted through the engagement hole. A second connector of a second signal transmitting member, which constitutes part of a signal transmitting unit, is inserted from below into a connecting hole formed in the substrate. In addition, when the resin mold portion is molded, the amplifying member is retained in a state with the engagement pin and the second connector being inserted, respectively, into the engagement hole and the connecting hole.

Abstract: A method for producing a spark plug for internal combustion engines, in particular for gas-powered internal combustion engines, having a metallic shell, a ceramic insulator held in the shell, a center electrode embedded in the insulator, at least one ground electrode attached to a front end of the shell, an end piece made of a precious metal and/or alloy attached to a front end of the center electrode, and a counterpart made of a precious metal and/or alloy attached to the ground electrode opposite the end piece, between which is a spark gap with a nominal width. The spark gap is produced initially with a width that is smaller, at least in places, than the nominal width, and is subsequently brought to its nominal width by removing material from at least one of the two surfaces of the end piece and the counterpart that delimit the spark gap.

Abstract: A ceramic glow plug includes a ceramic heater; a tubular sleeve which holds the outer circumference of the ceramic heater with a front end portion thereof protruding from the front end of the sleeve; and a tubular housing which surrounds a rear end portion of the ceramic heater and has a mounting portion for mounting the housing. The sleeve has a small-diameter portion which is accommodated in a front end portion of the housing and has an outer diameter smaller than the inner diameter of the front end portion of the housing, and a large-diameter portion which is connected to the small-diameter portion, disposed frontward of the front end portion of the housing, and has a diameter larger than the inner diameter of the front end portion of the housing. The front end portion of the housing is welded to the large-diameter portion.

Abstract: In a cross section including a central axis, a value L/D obtained by dividing an axial length L of an overlap portion where a metal contact surface located on a metal shell and on which a packing is in contact with the metal shell overlaps a projection plane located on the metal shell and on which a contact surface located on an insulator and on which the packing is in contact with the insulator is projected in a direction orthogonal to the central axis by a difference D between a radius of an outer circumference of a tube portion at a connection position to a step portion and a radius of an outer circumference of a leg portion at a connection position to the step portion is 1.2 or more. This ensures the force of constraint in the radial direction provided by the packing on the insulator.

Abstract: A crimping-pressing step including (1) a step of bringing the crimping jig into contact with a to-be-crimped portion and moving the crimping jig forward such that a load acting on the crimping jig reaches a preset contact load, and (2) a buckling step of further moving the crimping jig forward by a preset distance and then stopping the crimping jig. The difference between the target moving distance of the crimping jig and its actual moving distance is reduced by adjusting at least one of the preset contact load and the preset distance on the basis of at least one of a first overshoot amount in the step (1) and a second overshoot amount in the step (2).

Abstract: A spark plug includes: an insulator having an axial hole; a conductive member disposed around the insulator; a center electrode disposed inside the axial hole, having a bar shape extending in the axial direction, and located on a rear end side with respect to a front end of the conductive member; a ground electrode forming a spark gap between the ground electrode and the center electrode; and a connection part including a plurality of spokes extending in a radial direction whose inner ends are connected to the ground electrode, and connecting the conductive member to the ground electrode. The connection part includes a joint part that is jointed to an inner surface of the conductive member, and the ground electrode has at least one of a notch and a groove at a position that is different from a position connected to the spokes in a circumferential direction.

Abstract: An electronic component includes at least a contact member having, on a surface of a contact portion adapted to come into contact with another contact member, at least an undercoat plating layer and a main plating layer formed on the undercoat plating layer. A coating containing a fluorine-based oil is provided on the main plating layer, and the coating has a dry coating weight per unit area on the main plating layer of greater than or equal to 0.011 mg/cm2.

Abstract: A method for drying a seal material for use in manufacturing an ignition device, e.g., a spark plug. A free-flowing or loose seal material having a moisture content is provided and brought together with a desiccant for a time sufficient to produce a dry seal material by reducing the moisture content of the loose seal material to a desired level. Thereafter, the dry seal material and the desiccant may be separated from one another so that the dry seal material can be used to form a seal within an internal bore of a spark plug.

Abstract: A spark plug comprises a ground electrode including a chip whose one end has a cylinder shape having a diameter A from 0.8 to 1.2 mm and whose main component is a noble metal, and an electrode base material. In the ground electrode, a portion of the other end of the chip is joined to the electrode base material through a fused portion. The spark plug also comprises a chip-and-base-material interface in which the chip and the electrode base material contact each other and which is surrounded by the fused portion. In a cross section passing through a center axis, a distance between an end point Pa7 located on the chip-and-base-material interface and an end point Pa5 located on an interface between the chip and the fused portion is equal to or greater than 0.7 times the diameter A.

Abstract: In a spark plug, an annular gap is formed between a metallic shell and an outer surface of a leg portion of an insulator. A contact end position is provided at a front most position of a contact portion formed between a packing and the metallic shell. A radial distance between the outer surface of the leg portion and an inner surface of the metallic shell is a gap distance. A maximum end position is provided at the rear end of the annular gap maximum portion. The gap distance at a front end of the metallic shell is larger than the gap between the center electrode and the ground electrode. The metallic shell includes an increased inner diameter portion having an inner diameter at the front side relative to the contact end position. The maximum end position is located at the rear side relative to an intermediate position.

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 composite ignition device includes a positive electrode having a tip formed thereon that is bonded to a first insulator to form a firing cone assembly. A second insulator having a negative capacitive element embedded therein is attached to the firing cone assembly. A positive capacitive element is disposed in the second insulator and is separated from the negative capacitive element by the second insulator. The positive capacitive element is coupled to the positive electrode. The positive and negative capacitive elements form a capacitor. A resistor is coupled to the positive capacitive element. An electrical connector is coupled to the resistor and attached to the second insulator. A shell including a negative electrode having a tip is attached to the second insulator and the firing cone assembly and coupled to the negative capacitive element. The negative electrode tip is spaced apart from the positive electrode tip.

Abstract: A spark plug includes a ceramic insulator having an engagement portion, and a metallic shell provided around the ceramic insulator and having a protrusion. The protrusion has a diameter-decreasing portion, which seats on the engagement portion via an annular seat packing. On a cross section including an axial line, ?s>?p is satisfied, where ?p represents an acute angle (°) between a straight line orthogonal to the axial line and the contour of the engagement portion, and ?s represents an acute angle (°) between a straight line orthogonal to the axial line and the contour of the diameter-decreasing portion. In the aforementioned cross section, Hvo>Hvi is satisfied, where Hvo represents the Vickers hardness (Hv) of the seat packing at the midpoint of a first line segment, and Hvi represents the Vickers hardness (Hv) of the seat packing at the midpoint of a second line segment.

Abstract: Method for igniting a fuel/air mixture in a cyclically operating internal combustion engine comprising combustion chambers which are delimited by walls that are at ground potential, using an ignition device comprising an ignition electrode provided in each combustion chamber, in which method, via an electrical DC/AC converter, an electric oscillating circuit is excited, which is connected to the secondary side of the DC/AC converter, and in which the ignition electrode, which is guided through one of the walls delimiting the combustion chamber in a manner in which it is electrically insulated from said walls by an insulator and extends into the combustion chamber, constitutes a capacitance in cooperation with the walls of the combustion chamber that are at ground potential, and in which the excitation of the oscillating circuit is controlled so a corona discharge igniting the fuel/air mixture is created in each combustion chamber at the ignition electrode.

Abstract: A spark plug includes a tubular housing, a tubular insulator retained in the housing, a center electrode secured in the insulator, and a ground electrode provided at a distal end of the housing. The housing has a seat portion formed on its inner periphery. The insulator has a distal portion, a proximal portion, and a shoulder formed on an outer periphery of the insulator between the distal and proximal portions. The shoulder is arranged to seat on the seat portion of the housing with an annular packing interposed therebetween. On an inner peripheral surface of the seat portion of the housing which faces an outer peripheral surface of the distal portion of the shoulder, there are formed uneven portions that are arranged in a circumferential direction of the spark plug. Each of the uneven portions consists of a protrusion and a recess that adjoin each other in the circumferential direction.

Abstract: A spark plug is disclosed and comprises: a metal tube which interiorly defines an axis and is externally-threaded for engine block engagement; an insulator having a portion which is disposed inside the tube and extends therebeyond; a positive electrode extending through the insulator and projecting beyond the extending portion of the insulator; and an annular ground electrode coupled to the tube. The electrodes are configured such that a spark gap defined therebetween comprises an elongate channel which opens axially and away from said insulator and is substantially unobstructed in the axial direction. The ground defines a void having: a central portion occupied by the positive electrode in use; an annular channel surrounding the central portion; and a plurality of lobes, each being positioned with respect to the central portion in a manner analogous to the placement of the planet gears with respect to the sun gear in a planetary gear.

Abstract: A corona igniter (20) for emitting a radio frequency electric field and providing a corona discharge (24) includes a central electrode (22) at a positive voltage, a grounded metal shell (30), and an insulator (28) with an abruption (34) extending radially outward relative to the central electrode (22). The abruption (34) is typically an increase of at least 15% of a local thickness (t) of the insulator (28) over less than 25% of a nose length (el) of an insulator nose region (74). The abruption (34) is typically one flank (82) of a protrusion or a notch, and the flank (82) faces the shell (30). The abruption (34) reverses the electric field and voltage potential gradient along the insulator outer surface (32), repels charged ions away from the insulator (28), and thus prevents the formation of a conductive path between the central electrode (22) and the shell (22).

Abstract: A spark plug has a shell, an insulator, a center electrode, a ground electrode, and a firing pad. The firing pad is made of a precious metal material and is attached to the ground electrode. The firing pad has a side surface at a peripheral edge that can be flush or nearly flush with a free end surface of the ground electrode. This construction can help improve ignitability and flame kernel growth of the spark plug during a sparking event, and can provide better thermal management at the attached ground electrode and firing pad.

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: There is provided a spark plug for an internal combustion engine, including: a center electrode extending in the direction of an axis of the spark plug and having a core of higher thermal expansion coefficient than that of a front end thereof, the center electrode including a flanged portion radially outwardly protruding on a rear side thereof and a cylindrical portion located closer to a front end of the spark plug than the flanged portion and being smaller in diameter than the flanged portion; an insulator having an axial hole in the direction of the axis to retain the flanged portion in the axial hole with the cylindrical portion held in a loose-fit state in the axial hole; and a metal shell accommodating the insulator, wherein the spark plug satisfies the following condition: Cb<Cf where Cb is a difference between an inner diameter of the axial hole and an outer diameter of the cylindrical portion at an arbitrary axial position B in the direction of the axis; and Cf is a difference between the inner di

Abstract: An igniter for an internal combustion engine includes a center electrode, an insulator disposed about the center electrode, and a ground shield or a threaded portion disposed about the insulator, wherein the insulator includes a tip portion extending past an end portion of the ground shield and a tip portion of the center electrode extending through and away from the tip portion of the insulator. The igniter further includes a cap secured to the center electrode, wherein the cap extends past and covers a distal end of the tip portion of the center electrode and a distal end of the tip portion of the insulator. A spark gap is disposed between a peripheral edge of the cap and the end portion of the ground shield or threaded portion wherein the peripheral edge of the cap is spaced away from a surface of the tip portion of the insulator.

Abstract: A spark plug is provided. The spark plug has an insulative sleeve with a central axial bore and an exterior surface of a shaped tip portion. A coating is disposed on the exterior surface of the shaped tip portion and the coating comprises a transition metal compound or a combination of transition metal compounds, and an alkali metal compound. A center electrode extends through the central axial bore of the insulative sleeve. A metal sleeve is provided, wherein the insulating sleeve is positioned within, and secured to, the metal shell. A ground electrode is coupled to the metal shell and positioned in a spaced relationship relative to the center electrode so as to define a spark gap.

Abstract: A technique of reducing occurrence of multiple discharge in a spark plug. The spark plug has a main ground electrode and three auxiliary ground electrodes. The position at which first auxiliary ground electrode is joined to a metallic shell is located opposite the position at which main ground electrode is joined to the metallic shell, with respect to a center electrode. The positions at which second and third auxiliary ground electrodes are joined to the metallic shell are located opposite to each other with respect to the center electrode. When the width of first auxiliary ground electrode is represented by W, the shortest distance between second auxiliary ground electrode and third auxiliary ground electrode is represented by T, and a distance which is a component of the shortest distance T in a direction orthogonal to first auxiliary ground electrode is represented by Tp, a relation W?Tp is satisfied.

Abstract: Disclosed herein is a spark plug comprising an insulative sleeve having a central axial bore and an exterior surface and a center electrode extending through the central axial bore of the insulative sleeve. The insulating sleeve is positioned within, and secured to, a metal shell that serves as a mounting platform and interface to an internal combustion engine. The metal sleeve also supports a ground electrode that is positioned in a spaced relationship relative to the center electrode so as to generate a spark gap. The insulating sleeve includes a shaped tip portion that resides in a recessed end portion of the metal shell. A coating is disposed on the exterior surface of the shaped tip portion of the insulative sleeve. The coating comprises a metal oxide, a noble metal, late transition metal, or a combination comprising two or more of the foregoing metals.

Abstract: A spark plug for an internal combustion engine capable of ensuring sufficient gastightness of a combustion chamber and meeting demand for a reduction in diameter.

Abstract: A spark plug includes an insulator having an axial hole, a first inner circumferential surface, a second inner circumferential surface whose diameter is greater than that of the first inner circumferential surface, and a ledge portion connecting the first and the second inner circumferential surfaces. The spark plug also includes a center electrode having a large-diameter portion, a projection portion, and a circular columnar leg portion that projects into a space surrounded by the first inner circumferential surface. The spark plug includes a seal portion which fixes the center electrode within the axial hole. When C<A, A?C?B?A, where A represents a diameter of an imaginary cylinder having the minimum diameter required for surrounding the projection portion, B represents a maximum diameter of the large-diameter portion, and C represents an average diameter of the leg portion present in the space surrounded by the first inner circumferential surface.

Abstract: A spark plug includes a metal shell, a ground electrode joined to a front end portion of the metal shell and a nickel layer formed on the ground electrode, wherein the ground electrode has a base material exposed region in which a base material of the ground electrode is exposed; and wherein the nickel layer includes an outer-lateral-side nickel layer located on an outer lateral surface of the ground electrode at a position adjacent to the base material exposed region and satisfies a condition of LA?25 ?m, where LA is a length from a first part of the outer-lateral-side nickel layer having a thickness equal to 80% of a maximum thickness of the outer-lateral-side nickel layer to a second part of the outer-lateral-side nickel layer having a thickness equal to 20% of the maximum thickness of the outer-lateral-side nickel layer in a longitudinal direction of the ground electrode.

Abstract: Methods and systems are provided for identifying and indicating degradation of an engine cylinder spark plug. In response to a cylinder misfire event during selected engine operating conditions, followed by an occurrence of a threshold number and/or rate of pre-ignition events in the same cylinder, a controller may determine that the spark plug is degraded. The controller may limit combustion in the cylinder in response to the degradation. Additionally, cylinder pre-ignition mitigating steps may be taken.

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, which center is located at a front end side in a direction of the axis with respect to a front end of the center electrode.

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: The invention relates to a spark gap comprising a number of series-connected individual spark gaps which are placed in a stack arrangement, which are spaced apart from each other by insulating material discs and are provided with a spring contact, the individual spark gaps including ring-shaped or disc-shaped electrodes, and further comprising control elements for influencing the voltage distribution over the stack arrangement. According to the invention the ring-shaped or disc-shaped electrodes required to form one of the respective individual spark gaps are each inserted into an insulating body and held by same in a centered manner. The respective insulating material discs are located between and fixed by the insulating bodies.

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 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: 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.