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: An improved igniter and cable connector assembly for turbine engines. An igniter mounting adapter is secured to the engine. The igniter slides into a hole through the adapter and is retained by an enlarged head on the igniter. An annular seal is positioned around a high voltage terminal on the igniter head and a terminal on the cable connector is positioned against the igniter terminal. The cable connector is secured to the adapter, for example, by either a clamp assembly or a coupling nut or a quick release connector. As the cable connector is secured to the adapter, the seal is compressed between the igniter and connector insulators and, optionally, the connector terminal is rotated and pressed against the igniter terminal to establish a reliable electrical contact. The connector and igniter terminals preferably have mating conical or spherical surfaces, one of which may be an annular segment to provide an increased electrical contact area.

Abstract: A ceramic insulator structure for use in a spark plug is manufactured by mixing granular or powdery particles of AlN, Si3N.sub.4 or Al.sub.2 O.sub.3 with an organic binder and an auxiliary sintering agent, the average spherical diameter of the particles making up the resulting ceramic mixture being in the range 20-100 microns. The ceramic mixture is then pressed in a mold into a desired shape and sintered at a temperature of 1600.degree.-2000.degree. C.

Abstract: An igniter plug has a metallic shell, a front end of which has a tubular ground electrode. A hollow semiconductor tip is in the form of inversed frusto-cone shape, and placed within the tubular ground electrode. A tubular insulator is placed within the metallic shell to be in alignment with the semiconductor tip. A center electrode is placed within the insulator, a front end of the center electrode passing through the semiconductor tip to provide an annular discharge gap between the front end of the center electrode and that of the ground electrode. A low resistor layer provided on a front end surface of the semiconductor tip. An electrical resistance of the layer is determined to be smaller than that of the semiconductor tip, while a thickness of the layer is such that the layer precedes the semiconductor tip in forming a discharge path between the front end of the center electrode and that of the ground electrode only during a predetermined period after the igniter plug is initially operated.

Abstract: An igniter plug has a tubular metallic shell and an annular ground electrode each connected in series by an interfitting, and fixed by welding. The igniter plug further has a tubular insulator placed within both the metallic shell and the ground electrode, while a center electrode is placed within the insulator to be surrounded by the ground electrode. A plurality of lock arms are provided with a front end of the metallic shell, and each top end of lock arms has a pawl which is brought into an engagement with an inner wall of a groove which is provided with an inner surface of the ground electrode when the metallic shell and the ground electrode are connected, and at the same time, the insulator is brought into an engagement with an inner side of each lock arm to deter the lock arms from being flexed inwardly when the insulator is placed.

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: An internal combustion engine includes a cylinder head and a spark plug assembly adapted to be received in a cylinder head bore. The spark plug assembly includes a metal ground electrode element having an annulus disposed on a transverse annular seat of the cylinder head bore and a ground side electrode extending from the annulus. The ground side electrode is received in an axial slot of the cylinder head bore between the seat and a cylinder head inner wall and protrudes into the combustion chamber. The orientation of the ground electrode relative to the cylinder head, and thus to the geometry of the combustion chamber, is established by the circumferential location of the axial slot relative to the bore. The spark plug assembly also includes a center electrode element having a center electrode and surrounding insulator body.

Abstract: A surface gap type igniter plug comprising; a cylindrical metallic shell; a tubular insulator inserted into said metallic shell with a rear end projected from that of the insulator; a center electrode disposed to position at an innerside of the insulator, the electrode making its rear end of the insulator; a sleeve terminal located between an outerside of the electrode and an innerside of the insulator, the terminal being secured at a rear end to the center electrode by means of welding; a connector having an insulator sleeve interfit into an innerside of a metallic sleeve, the insulator sleeve being terminated short of a front end of the metallic sleeve; and the connector being securely capped to the metallic shell at a time of assemblage with the rear end of the tubular insulator interfit into an innerside of the insulator sleeve, and with the metallic shell interfit into an innerside of the metallic sleeve.

Abstract: A spark plug structure comprising; a cylindrical metallic shell; a joint type insulator having a center bore, and including a front half piece and a rear half piece, each made of a tubular aluminum nitride (AlN), and the front and rear half pieces being joined at their respective end by means of a glass sealant, and encased into the metallic shell; a center electrode placed into the center bore of the insulator; an elongated terminal placed into the rear half piece of the insulator; an electrically conductive glass provided to seal respective spaces appeared between the center electrode, insulator and the terminal; the front half piece having an elongated projection, the length of which is more than 2.0 mm, and the rear half piece having a recess the depth of which is more than 2.0 mm, the front and rear half pieces being jointed at the projection and the recess by means of an annular glass sealant which has thickness of less than 2.0 mm and length of more than 2.0 mm.

Abstract: A metal spark plug shell includes an L-shaped copper core side electrode secured in an axially extending slot on the metal shell. The side electrode includes an attachment end having a portion with an outer side that is threaded contiguous with the metal shell and another portion adjacent the end of the metal shell with a recessed outer side that is unthreaded so as to permit spark plug gapping without breakage of the side electrode. The heat-resistant sheath around the copper core on the inner side of the attachment end may be spot welded to the metal shell.

Abstract: A spark plug having a metal shell accommodating a dielectric core through which an electrode extends and terminates at one end in a tip spaced by a spark gap from an overlying ground wire that is bent between its ends and joined to the shell. That surface of the ground wire which confronts the electrode is grooved to enlarge its area and enable the wire to react like a bimetallic element in response to changes in its temperature and vary the size of the spark gap.

Abstract: A spark plug for use in internal combustion engines having a pair of electrodes between which electric spark discharge is effected. The spark plug has a spark discharge portion bonded by, for example, resistance welding to at least one of the electrodes and made of a base metal containing at least 90 wt % of chromium (Cr). A stress-relieving portion having a thermal expansion coefficient intermediate in value between those of the electrode and the spark discharge portion may be formed between the electrode and the spark discharge portion.

Abstract: At least one of center and ground electrodes of a spark plug has a thin layer formed by bonding noble metal powder on a discharge-related surface area of the electrode stock of said at least one of said center and ground electrodes in accordance with ultrasonic bonding. Instead of the thin layer, a discharge tip may be formed there by boring a hole in the electrode stock, filling noble metal powder, which has been obtained by coating spherical or flaky metal particles with a corresponding noble metal or noble metal alloy, in the hole and then bonding the thus-filled noble metal powder in accordance with ultrasonic bonding. As a further alternative, a tip made of a noble metal or an alloy thereof may be bonded by ultrasonic bonding or resistance welding in the hole with a layer or metal powder of a metal having good high-temperature erosion resistance or an alloy thereof interposed therebetween. The spark plug enjoys a long operating life.

Abstract: The prevention of electrode material erosion by undercutting in the outer electrode shell of igniter electrodes of jet engine ignition systems is prevented by the application of an electrical insulation coating. The coating is applied to the surface of the outer electrode shell which faces the ceramic insulation around the center electrode where erosion patterns are known to occur. The insulation material is selected from electrical insulation substances such as oxides of aluminum, tungsten, magnesium, beryllium or zirconium by choosing a non-porous electrical insulating substance with thermal expansion characteristics approximately equalling those of the outer electrode shell. Since a typical outer electrode shell is composed of 446 stainless steel, an optimum choice for the electrical insulation coating is AL.sub.2 O.sup.3 deposited with a coating thickness of between 5 and 10 mils.

Abstract: To reduce erosion of a platinum-containing electrode layer (3, 14) applied to the end face of the center insulator (1, 11) of the spark plug, a protective layer of ceramic, preferably aluminum oxide, is applied over the electrode. The aluminum oxide protective is sufficiently thin to permit arc-through or spark-through of the spark from a counter electrode (9, 19). This permits reduction of the thickness of the electrode layer to between about 5 to 15 micrometers, preferably about 8 to 10 micrometers, with a thickness of the protective layer of between 5 to 50 micrometers, preferably about 8 to 10 micrometers. Aluminum oxide is the preferred material for the center insulator, the protective layer, as well as an additive to the center electrode if it is made of a mixture of platinum and ceramic.

Abstract: To facilitate assembly of a central glass rod in an optical sensor-spark plug combination, electrical energy is conducted to the spark end of the combination by a high temperature resistant tube or sleeve 11 surrounding a central glass rod 2 for only a limited portion of the entire length; electrical energy is conducted to the high temperature resistant sleeve 11, which forms the sparking end of the spark plug, from a terminal connector 1 by a packing 10 of electrically conductive powder, which may include radio noise suppression resistance characteristics, held in place by a compression spring 8, in electrical connection with the terminal connector 1; or by a separate tube 12 surrounding the glass rod 1, and of non-heat resistant material, the glass rod 1 being separated from the other tube 12 by an adhesive which, at the connecting end of the spark plug, need not be high temperature resistant.

Abstract: This invention relates to an arc erosion-resistant composite material and methods for its manufacture and, more specifically, composite arc erosion resistant materials useful as electrodes in spark plug and jet engine igniters to promote longer useful life. An arc resistant material in particulate form is dispersed throughout a lower melting matrix metal clad in a tube of nickel or nickel alloy, and then worked to a very small outside diameter, after which the composite may be cut to provide electrode elements. Ruthenium and iridium, and their alloys comprise the arc erosion resistant material. Suitable matrix metals comprise silver, gold, copper, nickel, and palladium.

Abstract: A spark plug construction employing a non-eroding central electrode iridium tip in combination with a thermal conductor in intimate contact with the tip to act as a heat sink and maintain the tip below 1300.degree. F. (704.degree. C.).