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: The part of the distributor electrode in the breakdown region has a resistance of at least 400 ohms per millimeter. The total resistance of the electrode is in the range of between 0.5 and 1.0 kilo-ohms. The material is a mixture of a resistive ceramic material and a finely dispersed additive of metallic conductivity. Arrangements for creating surface discharge gaps thereby slowing down the sparking process and decreasing interference are also illustrated.

Abstract: To permit easy attachment, for example, by soldering, of a connecting lead wire to a conductive track on a ceramic plate connected closely adjacent to another plate which may also be ceramic, the first ceramic plate, at least, is bent away from the other ceramic plate at the connecting portion during manufacture; the manufacturing process includes heating the plate to be bent away to be in plastic condition and then applying a bending force to form the bend, permitting the so bent plate to cool, and joining the so-bent plate to the other plate with which it is to form a composite, for example, by glass melt. The bending force may be gravity, by permitting the unsintered plate, upon heating, to fall on a curved surface; or the bending force can be generated by applying a layer of a material having differential shrinkage to the flat, unsintered plate, and heating the composite, so that, upon differential shrinkage, the ceramic plate will be bent away from its originally plane, flat state.

Abstract: To improve current loading of the electrodes and thus improve the start-up operation of an electrochemical system which includes a solid electrolyte body, particularly at temperatures in the order of about 300.degree. C., the solid electrolyte body and the electrode layer thereover has an intermediate coating of fully stabilized zirconium dioxide applied; for example partially stabilized zirconium dioxide is fully stabilized in its surface region by yttrium or ytterbium oxide. This intermediate layer, while improving the current carrying capability of electrodes applied thereover, additionally prevents the occurrence of damage to the microstructure of partially stabilized solid electrolyte ceramic, particularly under changeable temperature loading, so that, if the solid electrolyte body essentially entirely consists of partially stabilized ceramic, the additional fully stabilized coating or surface zone can also be provided where the solid electrolyte body does not carry an electrode layer.

Abstract: To improve operation and output voltage, particularly at 400.degree. C. and less, an oxygen sensor, especially adapted to determine oxygen content of automotive exhaust gases, is constructed by utilizing two electrodes applied on a body of stabilized zirconium dioxide, for example a closed tube, by making an electrode exposed to the exhaust gases in form of a mixture of finely dispersed ceramic material and a platinum-rhodium alloy, the ceramic material being present at about 40% (by volume) and 60% (by volume) platinum-rhodium alloy of 50-94% platinum and 50-6% rhodium (by weight). The second electrode, exposed to a reference gas comprises an alloy of palladium and another noble metal in a ratio of about 19-90% (by weight) Pd and 81-10% (by weight) noble metal. This electrode may also contain up to 40% (by volume) finely dispersed ceramic material. The electrode exposed to the exhaust gases is covered with a porous coating.

Abstract: To permit efficient heat transfer from a carrier tube (22) surrounding a tubular solid electrolyte body (11') having outer and inner electrodes (14, 18) applied thereto, the tubular heater element carrier body (22) supports a wire or resistance track heating element (25) at the inner surface thereof, the heater element (25) being spaced from the outer surface of the solid electrolyte tube (11') forming part of the sensor element (11) by a distance at the most of 1 mm, preferably less than 0.5 mm, the wall thickness of the heater element carrier tube (22) preferably being between 0.3 and 0.8 mm thick, the carrier tube being made of ceramic, such as aluminum oxide, or internally insulated metal.

Abstract: To improve response time and provide an electrode which has good adhesion to a solid electrolyte body, typically of zirconium, to be used in lambda sensors or polarographic current limit sensors, and additionally enhance the loading capability thereof, the pre-sintered or fully sintered solid electrolyte body, typically of zirconium dioxide, has an electrode layer applied thereto on which, in advance of sintering thereof, a cover layer is applied which, when sintered, develops pores. The cover layer is a ceramic material, sintered together with the electrode on the solid electrode body. This results in higher loading capability and decrease in response temperature to about 250.degree. C. The sensors can be used as lambda sensors and polarographic current sensors, to determine oxygen content in exhaust gases, typically for automotive engines, as well as in high-temperature fuel cells, high-temperature batteries, and high-temperature electrolysis cells.

Abstract: To simplify manufacture and provide a polarographic sensor of high response speed, operating according to the current limiting principle, an oxygen molecule migration barrier is provided leading to the cathode by separating the cathode from the space where the gas to be tested exists by a wall through which a hole is provided which extends therethrough to a small space immediately above the cathode defined by support elements placed immediately on the cathode. The hole, or a plurality of holes, is so dimensioned that the diameter thereof, with respect to its length, is small, with diameters of between 0.01 to 0.06 mm and a length of at least about 1 mm being suitable.

Abstract: To increase the response speed and sensitivity, while providing higher output voltages and permitting higher loading of the electrodes of gas sensors, particularly exhaust gas sensors to determine the transition of exhaust gases from internal combustion engines between reducing and oxidizing state, the sintering activity of the electrode which, typically, a cermet electrode, is selected to be less than that of the solid electrolyte body so that the resulting pore structure will be more open than that of the solid electrolyte body. The electrodes, essentially, consist of finely divided ceramic material, such as zirconium oxide, and finely divided electron conductive material such as platinum.

Abstract: To measure partial oxygen pressure in gases, particularly exhaust gases of automotive-type combustion engines, a solid electrolyte plate of elongated rectangular configuration has at least one electrode pair applied to a single surface thereof, which is exposed to the measuring gas. Preferably, the gap between electrodes is elongated, by forming the electrodes in comb-interdigited form. A thermocouple - temperature sensor can be applied between connecting tracks for the electrodes which extend longitudinally of the electrolyte plate towards the other end thereof, through a sealing mass holding the plate within a housing, the other end forming, simultaneously, a connection terminal for connection to an electric connector or plug. A heating element can be placed on the obverse side of the plate, preferably in the position in the gap between the electrodes.

Abstract: To facilitate mass production and permit ready introduction of a substance which provides an oxygen partial pressure reference level, for example the oxygen in ambient air, an elongated plane flat plate-like solid electrolyte body is provided with electrodes thereon, and one of the electrodes is covered by a trough-like cover element to form the reference electrode, the space beneath the trough-like element and the electrode itself being available for the substance which may, but need not be, the oxygen of air, and may be a solid material providing a reference oxygen partial pressure level. The cover plate may, itself, be made of solid electrolyte material and may form a portion of another sensing element, so that a plurality of sensing elements can be superimposed in sandwich-like fashion. A heater element can be applied to a flat plate element of the assembly where desired. The sensors can operate in the potentiometric or polarographic mode.

Abstract: To decrease the quantity of catalytically active noble metal used in a Cermet (ceramic-metal) electrode, particularly one containing platinum, the electrode has a non-uniform noble metal concentration, with respect to its cross section, so that the outer region thereof consists essentially only of ceramic material, protecting the softer noble metal which is subject to erosion, and permitting a higher concentration of noble metal close to the solid electrolyte body where it is most needed.

Abstract: To increase the sensitivity of internal combustion engine exhaust gas sensors, which provide a voltage jump output upon transition of the composition of the exhaust between reducing and oxidizing state, and to maintain the porosity of a platinum, or platinum metal alloy layer forming an electrode on a body of zirconium dioxide, the electrode or electrode layer has dispersed therein an oxide or a carbide of a metal which impedes or inhibits recrystallization at the temperatures to which the sensor is exposed, for example 1000.degree. C.

Abstract: To improve adhesion of a porous cover layer over a platinum or platinum-rhodium electrode layer on a solid electrolyte body, for example of stabilized zirconium dioxide, the electrode layer is applied in form of interrupted, adjacent strips leaving gaps exposing the solid electrolyte body therebeneath. The porous cover layer will adhere well to the solid electrolyte body, thus protecting both the electrode and the cover layer against flaking off under high-temperature and temperature variation conditions. The sensitivity can be improved by interposing a layer of ceramic mixed with platinum or a platinum rhodium between the solid electrolyte body and at least some of the electrode strips, the adhesion of the porous cover layer over the interposed thick-film layer, where exposed between the portions of the electrode on the solid electrolyte body being sufficient for the intended purpose.

Abstract: Oxygen sensors having a fine-grained stabilized cubic zirconium dioxide electrolyte contact respective electrodes. The zirconium dioxide contains between 15% and 50% by volume of Al.sub.2 O.sub.3 in a crystalline state and has good mechanical and thermal properties. The oxygen sensor may have a composite zirconium dioxide solid electrolyte element. The invention also includes a wider range of related Al.sub.2 O.sub.3 - containing stabilized cubic zirconium dioxides containing between about 8% and 85% by volume Al.sub.2 O.sub.3. The invention further provides methods of manufacturing such Al.sub.2 O.sub.3 - containing zirconium dioxide and for manufacturing oxygen sensors.

Abstract: Stabilized zirconium dioxide compositions sintered with a silicate flux and stabilized with (i) calcium oxide and (ii) magnesium oxide. The stabilized zirconium dioxide can be sintered at temperatures between 1460.degree. C. and 1480.degree. C. to form solids having high mechanical strength and a specific resistance of 1M.OMEGA.cm at a low temperature. The invention also provides oxygen sensors containing at least one measuring cell which is an oxygen concentration cell having two electrodes separated by and in ionic communication through a solid stabilized zirconium dioxide electrolyte which is prepared from the said compositions.

Abstract: To provide protection to the sensitive solid ion conductive electrolyte, a metal sleeve is placed to surround the electrolyte, with clearance, and formed with openings having an increasing cross-sectional area starting from the housing or socket towards the bottom of the solid electrolyte tube to provide an approximately even temperature gradient upon exposure of the element to exhaust gases, the sleeve being additionally so formed that deflection surfaces or vanes are formed internally thereof, for example by punching the openings through the sleeve as elongated slots leaving deflecting vanes, to deflect gases passing through the openings from direct impingement on the solid electrolyte tube to protect the solid electrolyte tube against impact and contamination.

Abstract: Electro-chemical sensor to determine oxygen concentration in hot internal combustion exhaust gases in the form of a closed, tubular element having a solid ion conductive electrolyte; an electron-conductive coating on the inner surface thereof; a porous or fissured electron conductive layer on the outer surface of said solid electrolyte or on a part of said surface, part of the pores or fissures being macroporous, said layer being of a material which catalyzes the formation from said hot exhaust gases of those compounds that are thermodynamically stable at the exhaust temperature; and a porous protective electrically insulating coating on said porous electron-conductive layer. Preferably, a top coating of a heat-resistant metal is applied, which top coating has additionally properties to act as a getter with respect to poisons affecting the catalyzing material.

Abstract: Methods for making an exhaust-gas-sensing element which is an oxygen concentration cell having a solid electrolyte with an electron-conductive surface on the side exposed to the reference air and a catalytic electron-conductive layer containing micro pores which extend through to the solid electrolyte on the other surface which is adapted to be exposed to the exhaust gases. The electron-conductive catalytic layer is covered with a porous protective layer. The method comprising applying the catalytic layer by means of thin layer techniques and then heating to form the micro pores; or by applying a paste comprising ceramic particles, catalytic particles and a thinning oil and sintering.

Abstract: Glass powder is wetted with an aqueous solution or emulsion of an organic binder and mixed with carbon black in the form of soot or lampblack. The resulting material is packed between the parts of the central electrode of a sparkplug and fired at a temperature sufficient to fuse the glass to produce a gas-tight seal with electrically conducting properties. Up to 5% of metal powders may be included in the material if it is desired to prevent the resistance from rising during service. Oxides or carbides and certain other metal powders may be added to bring the thermal expansion coefficient to a desired average value.