Abstract: In a preferred embodiment, a resistor spark plug having a low level of RFI emissions, achieved by means of reducing the capacitances within the spark plug, so that the resistor in the spark plug is more effective. Reduction of the capacitances is accomplished by providing a resistor of relatively narrow diameter, providing a clearance space between the shell of the spark plug and the portion of the insulator where the resistor is located, and by providing an extended shell around the insulator above where the resistor is located. The improved effectiveness of the resistor reduces the energy transferred across the spark gap and, therefore, reduces erosion of the electrodes.

Abstract: A spark plug containing a resistor which is a sintered body made from a mixture comprising coarse glass particles and fine glass particles, coarse ceramic particles and fine ceramic particles, and carbon black in special proportions is improved in noise signal suppression effect.

Abstract: A spark plug with a heat pipe in the centerbore of the insulator thereof for controlling the operating temperature of the spark plug firing end automatically. A vaporizable medium in the heat pipe vaporizes when the load on the engine causes the temperature of the engine cylinder in which the spark plug is installed to rise into a temperature range in which damage to its firing end can occur. In that temperature range, the change of state of the vaporizable medium extracts heat from the firing end to prevent its overheating. The vapor pressure of the vaporied medium moves the vapor to a condensation zone where it condenses and releases its heat by a change of state. The condensate is returned to the vaporization zone by capillary means and the cycle is repeated as long as the firing end is in the overheating range of the spark plug.

Abstract: A spark plug with a surface discharge section for internal combustion engines comprising an insulation body having an inner cavity for receiving a mass of an electrically conductive material, and a bore extending from the inner cavity and through which extends a central electrode which is formed integral with the surface discharge surface, is made of an electrically non-conductive material, and has on an outer surface thereof in the area of the mass and the bore an electrically conductive film, and, in the area defining the surface discharge section a film having no intrinsic conductivity after sintering.

Abstract: An electrode for electrical devices subject to electrical erosion effects such as spark erosion. Selected areas of the surface of the firing end of the electrode are provided with a thin coating of electrical-erosion resistant material such that the erosion of the electrode adjacent the coating produces a thin edge which promotes current emission therefrom. Preferably the coating is a layer of aluminum from 0.5 mil to 10 mils in thickness. In further embodiments, the electrode is aluminum or an alloy thereof coated with an unalloyed aluminum. In other embodiments, a longitudinal coaxial hole or one or more slots are provided in the firing end of the electrode.

Abstract: A spark plug for internal combustion engines provided with a noble metal tip on the pointed top of a spark plug center electrode. The noble metal tip is welded to the center electrode top end by heating and pressing the portion to be welded. After the welding, the center electrode is shaped to provide the pointed top. The noble metal tip is a platinum alloy consisting of platinum of 85 through 70 in weight percentage and iridium of 15 through 30 in weight percentage.

Abstract: A spark plug having a heat pipe incorporated in the center conductor assembly in the insulator centerbore. The heat pipe is thermally non-conducting below a design temperature such that the firing end of the spark plug retains heat to burn off fouling deposits. Above the design temperature range, a vaporizable medium in the heat pipe vaporizes such that its change of state extracts heat from the firing end, the vapor moving to the cooler part of the heat pipe and condensing to release its heat by a change of state. Capillary means running the length of the heat pipe returns the vaporizable medium to the firing end of the heat pipe. This circulation of the heat pipe medium which occurs when the firing end exceeds the design temperature transfers heat from the firing end to prevent its overheating. The heat pipe in the insulator thus controls automatically the operative heat range of the spark plug.

Abstract: An electrically stable radio frequency interference suppressing glass-type resistor seal composition forming a gas-tight seal within the center bore of a ceramic insulator is disclosed that contains borosilicate glass, barium borate glass, mullite, zirconia, carbon black, bentonite, sucrose, lithium carbonate and small, approximately equal amounts of antimony and silicon.

Abstract: In a spark plug with center electrode and body electrode in which the cylindrical center electrode comprises in its end face a blind bore in which a pin-shaped small-volume noble metal insert is inserted and fixed by upsetting, it is provided that the front region (1a) of the center electrode (1), provided with end-side bore (2) and insert (3) disposed therein, is reduced radially over almost the entire length of the bore (2), the reduced region (1a) having a constant diameter, and that a further pin-shaped small-volume noble metal insert (5) is fixed in a bore (4) formed coaxially with the bore (2) in the body electrode (6). The production of the spark plug can proceed from commercially usual spark plug parts made on conventional production machines; the noble metal insert of the spark plug is securely attached in the center electrode and the body electrode part opposite the noble metal insert has a reduced burnup, thus increasing the life of the spark plug.

Abstract: An improved method is disclosed for forming a composite spark plug electrode having a thermally conductive metal core embedded within a corrosion-resistant metal sheath. Initially, a composite billet is formed by positioning a mass of the thermally conductive metal within a cup formed from the corrosion-resistant metal having a closed end and an open end. The corrosion-resistant metal at the open end of the cup extends further than the thermal conducting metal. The composite billet is passed open end first through an extrusion orifice. A head may be formed on the end of the resulting extrusion for welding to a wire terminal or an end of a wire terminal is positioned within the open cup end prior to passing the cup through the extrusion orifice for mechanically bonding the extrusion to the terminal. Excess metal on the end of the cup may be removed from the resulting composite electrode or it may be sheared from the electrode and repositioned axially along the electrode to form a shoulder.

Abstract: A spark plug for internal combustion engines has center and grounded electrodes having surfaces disposed adjacent to a spark gap between the electrodes and directed to but spaced from each other and also have side faces converging toward the spark gap. Each of the electrodes is provided with a piece of a noble metal secured to the surface directed to the other electrode. The noble metal pieces provided on both electrodes define the spark gap therebetween.

Abstract: A spark plug having an internal resistor and resistor-bore seal is disclosed. The spark plug comprises a shell, an insulator assembly carried by the shell and a ground electrode structurally integral with the shell. The insulator assembly comprises an insulator having a firing end and a terminal end, and a bore extending therethrough, and a center electrode within the bore of the insulator, and having a firing end firing in spark gap relationship with the ground electrode. The assembly also comprises a resistor positioned within the bore of the insulator and in electrical contact with the center electrode. The longitudinal position of the resistor in the bore of the insulator is radially inward of the shell. The assembly also includes an electrically nonconductive and substantially gas-impervious seal compacted between the walls of the bore of the insulator and longitudinally extending walls of the resistor. The electrically non-conductive material can be covered by an electrically conductive cup.

Abstract: A spark plug with a rivet-like tip center discharge electrode is obtained by melting powdery metal essentially consisting of noble metal Au, Ag and/or alloys thereof with Pd or the like charged in a small end bore formed at a discharge end bottom of a ceramic insulator then allowing to cool. Sealing and/or resistor incorporation together with setting (sealing) of a terminal rod may be done one-stepwise with the center electrode formation or two-stepwise after the center electrode formation. A resultant space in the center bore may be utilized for various purposes.

Abstract: A sparkplug for internal combustion engines which has a central electrode extending to the ignition end. The central electrode has an electrically non-conductive core pin with an electrically conductive outer layer on the cylindrical surface of the core pin. The central electrode is positioned in the lengthwise bore of the sparkplug insulator portion, preferably without any clearance between the insulator and the ignition end portion of the central electrode. The core pin is preferably made of a material which has shrinkage characteristics and a thermal coefficient of expansion substantially the same as those of the insulator. Most preferably the same material is used for both components. The electrically conductive coating layer of the central electrode is preferably a conductive metal-ceramic mixture. The coating layer may be in the form of a resistance element and/or contain a pre-ignition discharge gap.

Abstract: A spark plug with a sphere-like center discharge electrode is obtained by pressing a sphere-like metal essentially consisting of noble metal Au, Ag and/or alloys thereof with Pd or the like set on a small end bore formed at a discharge end bottom of a ceramic insulator. Sealing of a sealing material and/or resistor material together with setting (sealing) of a terminal body may be done simultaneously with the pressing of the sphere-like metal on the small end bore by means of hot-pressing applied on the terminal rod head.

Abstract: A resistor spark plug having, between a terminal screw and a center electrode, electrical conductive glass seals and a resistor glass seal therebetween, said electrical conductive glass seals containing carbon, one or more metals and glass and said resistor glass seal containing carbon, silicon carbide, glass, boron carbide or titanium carbide, and if desired a filler, has a small voltage coefficient of resistance and stable properties and is effective for reducing noise from an ignition system.

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: An electrical igniter device for a combustion apparatus such as a gas turbine comprises a unitary tubular conductive shell into which an assembly of coaxially arranged ingniter components are breech loaded. A spark electrode and a terminal extension are positioned in electrical contact within a hollow electrode insulator in the assembly. The electrode insulator is longitudinally positioned in the device between an internal shoulder in the shell and a removable retaining sleeve. The retaining sleeve is in turn held in position against the electrode insulator by an end coupling which is threaded into the breech end of the shell. An external lead connected to the end coupling transmits an electrical charge through the coupling to the shell. Inwardly extending tabs formed off the end of the shell opposite the breech end, together with the spark electrode within the shell, define a spark gap.

Abstract: A spark plug and connector assembly having a spark gap formed from two electrodes which are both electrically isolated from ground. The spark plug includes an insulator mounted in a tubular metal shell having a threaded end for engaging a corresponding opening into a combustion chamber in an internal combustion engine. The two electrodes are mounted within separate parallel bores through the insulator. Each electrode has a tip projecting from the insulator for defining the spark gap. The electrodes also have terminal ends which are recessed within the insulator bores. The electrode terminal ends are centered within and spaced from the walls of the bores. Tubular connectors attached to the ends of two high-voltage ignition cables are received within the insulator bores and slide telescopically onto the electrode terminal ends. The connectors are also recessed within the insulator bores to prevent arcing therebetween.

Abstract: An improved semiconductor and semiconductor coating for alumina electrical insulating devices is disclosed. The semiconductor is prepared by applying a layer of a mixture of monoxide and sesquioxide combination to an alumina body and firing at a temperature of 2300.degree. or above thereby forming a stable spinel. The electrically-conductive monoxide can be FeO, Cu.sub.2 O, CuO, NiO, CoO or MnO. The sesquioxide can be Fe.sub.2 O.sub.3, Cr.sub.2 O.sub.3, Ga.sub.2 O.sub.3, Ca.sub.2 O.sub.3, Mn.sub.2 O.sub.3, Al.sub.2 O.sub.3 or Ti.sub.2 O.sub.3.