Abstract: A spark plug has a cylindrical metal shell, a ground electrode and an insulator fixedly supported within the metal shell with a front end of the insulator extended beyond a front end of the metal shell. The insulator has an axial bore in which a center electrode is placed to form a spark gap with the ground electrode. The front end of the metal shell is generally flush with or somewhat recessed into an inner wall of a combustion chamber of an internal combustion engine when the spark plug is mounted on a cylinder head of the engine. The front end of the insulator extends at least 4.0 mm from the front end of the metal shell.

Abstract: In a spark plug, a metal shell has first and second open ends. A ground electrode is formed in integral with the metal shell, provided on the first open end of the metal shell. An insulator has an axial bore, held in the metal shell. A center electrode in the bore of the insulator has a front end extending beyond the insulator. At least one row of intermediary electrode strips is arranged intermittently in a circumferential direction around an end portion of the insulator so as to form a series of spark discharge gaps circumferentially around the end portion of the insulator, and disposed between the ground electrode and the end portion of the center electrode.

Abstract: The invention includes a spark plug for a combustion engine including a center electrode having a tapered portion with a plurality of ridges formed thereon. The spark plug may also include a tapered, ground electrode positioned over the center of the center electrode. The tapered center and ground electrodes allow for flames to propagate freely from the spark gap into the combustion chamber and to ignite an air-fuel mixture in the chamber leading to smooth idle and faster starts.

Abstract: Center and earth electrodes are melted at the predetermined regions on the tip thereof where noble metallic chips are fixed. Then, the noble metallic chips are sunk in the melted portions of these center and earth electrodes so as to form protruding portions along outer peripheries of the noble metallic chips. Thus, the noble metallic chips are fixed to the electrodes through the protruding portions. Next, the noble metallic chips are irradiated by energy-condensing light through the protruding portions thus formed. With this irradiation, the center electrode is welded to one noble metallic chip, while the earth electrode is welded to the other noble metallic chip.

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 system (20) incorporating a spark plug and an associated venturi passage (38), said spark plug being spaced from the venturi passage (38) and projecting outwardly from one end thereof; and an electrode member (32) surrounding one end of an insulator member (21) which in mm surrounds and is spaced from a main electrode (23) carried by the insulator member (21) with at least the tip of said main electrode (23) being so positioned whereby to create sparks between itself and the surrounding electrode member (32). The electrode member (32) is so shaped to define, with the insulator member (21), a pre-combustion chamber (30) surrounding the main electrode (23). The electrode member (32) has at least one aperture (29) related in space to the tip of the main electrode (23) of the insulator member (21) and the associated venturi passage (38), and such as to allow communication between the cylinder chamber of an associated engine and the pre-combustion chamber.

Abstract: A spark plug for an Internal combustion engine is provided. When it is assumed that the distance of a first spark gap (g1) defined by a central electrode (8) and a first grounding electrode (16) whose width is "A" and which is axially opposed to the central electrode, and a second spark gap (g2) defined by the central electrode and at least one second grounding electrode (21) whose width is "B" and which is opposed to the side surface of the central electrode, the relationship defined by 0.5.ltoreq..SIGMA.Bn/A.ltoreq.1.5 is established, wherein "n" represents the number of the second grounding electrode to reduce the discharge voltage of the spark plug and maintain a high heat resistance. Preferably, the spark plug satisfies the relationship defined by 0.1 mm.ltoreq.g2-g1.ltoreq.0.4 mm to improve the ignitability of the spark plug.

Abstract: A spark plug having a low discharge voltage and good ignition performance. The object is achieved by means of a structure which satisfies the conditions:g3.gtoreq.1.2-g1;g2.ltoreq.g3-(d2-d1)/2;g1.ltoreq.g2.ltoreq.1.6; and0.ltoreq.h.ltoreq.2when the first spark gap size is made to be g1 mm, the second spark gap size is made to be g2 mm, the shortest distance between the center electrode tip surface peripheral portion and the second ground electrode tip surface outer end portion is g3 mm, the center electrode tip portion diameter is d1 mm, the center electrode body diameter is d2 mm, and height from an edge of said tip surface of said second ground electrode to said tip surface is h min.

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: A spark plug with a central electrode insulated against the plug thread having ground electrodes electrically connected to the plug thread, in which a prism-shaped cap is arranged at the end of the central electrode in the combustion chamber and the ground electrodes are parallel to the sides of the prism of the cap. The ground electrodes consist of at least one holder of a base or semi-precious metal on which a thin electrode layer of platinum or a platinum alloy is arranged facing the cap of the central electrode. The ground electrodes are configured in the form of a V-shape or a Y-shape.

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: In a multi-gap type spark plug for an internal combustion engine, the spark plug has a cylindrical metallic shell into which a tubular ceramic insulator is enclosed. The insulator has a tapered front leg portion, a front end of which extends beyond that of the metallic shell. A center electrode is enclosed into the insulator, having at a front end thereof, a filing tip extending beyond that of the insulator. A plurality of L-shaped outer electrodes each having a vertical piece and lateral piece, the vertical piece depending from the front end of the metallic shell to surround the front end of the insulator, while the lateral piece having an inner surface arranged in parallel with a front end surface of the insulator, and having an end tip terminated to oppose an outer surface of the firing tip through a spark gap established therebetween.

Abstract: A sparking plug with a central electrode insulated in respect of the plug screw-thread and with earth electrodes which are electrically connected to the plug screw-thread, there being at the combustion chamber end of the central electrode an attachment part which consists at least partially of platinum or a platinum alloy, the spark gaps being disposed between it and the earth electrodes which extend to it from the side. According to the invention, the attachment part takes the form of a prism, the top surface of which faces the combustion chamber. Furthermore, the earth electrodes extend laterally alongside the side faces of the substantially prismatic attachment member parallel with the edges of top or base surfaces of the prism. This ensures considerable stability and low burn-off. Furthermore, the electrode gap can easily be adjusted.

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 configuration having improved operational characteristics to achieve a greater efficiency in internal combustion engines. The ground electrode of the spark plug is configured to have two equal width prongs that diverge from each other in a uniform manner from a point that is substantially on the projection of the periphery of the center electrode. At least one of those prongs is redirected in its outer portion so as to be directed toward the other prong. This redirected portion begins substantially along a projection of the periphery of the center electrode such that the terminal or free end of the prong extends beyond the extension of this periphery. In a second embodiment, the second prong is also redirected at an outer portion toward the first prong such that a completely symmetrical mirror-image prong is formed about a plane passing through the axis of the center electrode and the vertex.

Abstract: A spark plug for internal combustion engines includes a third electrode in addition to a center electrode and a ground electrode which define a normal or main spark gap. Defined between the center electrode and the third electrode is an auxiliary gap adjoining the normal gap and adapted to produce a capacitive discharge at a voltage lower than that of the normal gap, and a discharge is induced across the normal gap by the capacitive discharge across the auxiliary gap.

Abstract: A spark igniter is disclosed. The igniter comprises a metal shell having a firing end which terminates at its lower end in an annular ground electrode, an insulator, a center electrode and a plurality of inserts embedded within and bonded to the metal shell. The insulator is sealed within the metal shell and has a central bore within which the center electrode is sealed and a surface extending inwardly toward the bore from the ground electrode. The center electrode has a firing end which is in spark gap relation with the ground electrode of the metal shell and is so positioned that a spark discharge between the firing end and the ground electrode occurs along the inwardly extending surface of the insulator. The inserts are composed of an oxidation and erosion resistant material, for example iridium, platinum, rhodium, ruthenium, osmium, tungsten or an alloy or ductile alloy of one of the foregoing metals.

Abstract: An ignition system for an internal combustion engine having a capacitive plasma jet plug including a capacitor in parallel with the series combination of an auxiliary gap and a plasma cavity. The auxiliary gap increases the required breakdown voltage before the plasma cavity generates a spark and obtains supplemental energy from the energy stored in the capacitor.

Abstract: A spark plug includes a body of dielectric substance mounted on one of central and earth electrodes and having polarization effects. A gap for capacitive discharge is defined between the body of dielectric substance and the other of the electrodes, and a gap for inductive discharge is defined between the electrodes, which gap for inductive discharge is larger in dimension than the gap for capacitive discharge. With the arrangement, capacitive discharge to be produced in the early stage of discharge is caused at low discharge breakdown voltage due to polarization effects of the body of dielectric substance, and inductive discharge taking the main part of discharge for ignition is produced by utilizing the capacitive discharge of low voltage as trigger, thereby lowering discharge breakdown voltage to improve ignition performance of the spark plug.

Abstract: A spark plug for an internal combustion engine; the plug including a pair of electrodes spaced alongside each other, and extending through an insulator fitted in a metal casing that is threaded, so as to be screwed into the engine, each electrode being intercepted by a solid state H.V. time delay device, which, in one example thereof, may comprise a high voltage diode, and, in another example, may comprise a solid state semi-conductor or the like.

Abstract: The spark plug center electrode is a composite of a jacket of corrosion resistant material, central filamentary core electrode elements, likewise of corrosion resistant material, and a matrix of thermally and electrically highly conductive material in which the corrosion resistant filamentary elements are embedded, filling the electrode within the outer jacket; in accordance with the present invention, the matrix material is recessed with respect to the jacket and the sparking ends of the corrosion resistant filamentary material to increase lifetime and to provide protection for the electrically and thermally highly conductive material and ensure ignition of even comparatively lean fuel-air mixtures. The electrode has an overall diameter in the order of about 2.4 mm, the recess of the matrix material being between 50 to 500 .mu. m, preferably about 100 to 250 .mu. m; a platinum coating having a thickness of preferably between 40 and 50 .mu. m can be provided to cover the exposed end of the electrode.

Abstract: A spark plug wherein corona discharge is employed to create a long arc and to determine, in part, the path of the arc, electrodes of the spark plug being shaped, oriented and positioned to create an arc of desired length, orientation and at a desired location as well as to effect electromagnetic interaction between electric current in the arc and the current in at least one of the electrodes to provide a force on the arc which acts in consort with the electrode shapes, positions and orientations to control its spatial behavior, the electrode configuration being further selected so that ionized species in the flame of ignited fuel are subjected to a high electric field over a substantial volume.

Abstract: A discharge device for igniting a fuel-air mixture whereby fuel droplets in the mixture are electrically charged and, under the influence of an electric field, caused to congregate at a region thereby concentrating the mixture at said region, means being provided to create an arc at said region. A device of more general use is also disclosed.

Abstract: A spark plug having multiple air gaps is described. The multiple gaps are defined by at least three electrode members defining at least two air gaps. A first electrode member is communicated to a ground potential while a second electrode member, the electrode member which is maximally spaced apart from the first electrode member, is communicated to a source of high voltage potential. The remaining electrode members are positioned intermediate the first and second electrode members and are arranged to be coupled by high resistance electrical means to either the ground or the high voltage potential. In a preferred embodiment, the high resistance means comprise a ladder type resistance network embedded within the ceramic body of the spark plug and electrically interconnecting the intermediate electrode members and the electrical connecting cap of the spark plug device. The air gaps so formed are broken down in sequence and share in the dissipation of the stored energy.

Abstract: An internal combustion engine spark plug including an outer metal shell, a central electrode and a side electrode extending from the shell toward the central electrode to form a spark gap is provided with an open element formed of rigid metal wire resistant to the spark plug ambient use conditions, the member surrounding the spark gap and being spaced from the spark gap a distance at least equal to the width of the spark gap. Among the forms of the wire member are a pair of U-shaped wire members each having at least one leg secured to the shell and a horizontal linear cross leg parallel to and coplanar with the side electrode, two pair of such members arranged in quadrative with the cross legs forward of the side electrode, the members may have thinner wire wrapped about its legs, and an element including a pair of laterally spaced L-shaped wire members with the vertical legs connected to the shell and an intermediate L-shaped member formed of twisted wire with a horizontal leg underlying the side electrode.

Abstract: A multiple air gap spark plug is provided with an unobstructed air gap spark generating region between the primary electrodes. The high voltage or primary electrodes are arranged to be in confronting relation for spark generation with the intermediate or secondary electrodes arranged to be on either side of the straight line path between the high voltage electrodes. The resulting sparks generated in each air gap between adjacent electrodes will coalesce into a single spark kernel existing between the primary electrodes and laterally bounded by the secondary electrodes.