摘要:
An electrochemical measuring sensor is proposed for determining the oxygen content in exhaust gases which has a base body made of an ion-conducting solid electrolyte in the form of a tube closed at one end, an inner electrode, an outer electrode disposed on the external surface of the probe block and having a conductor track on the connection side which has a covering layer, a ceramic protective layer and a metallic sealing ring for sealing the reference space from the exhaust gas space and for making an electrical contact to the housing in which the measuring sensor is to be inserted. The electrochemical covering layer covering the conductor track is brought down on the reference side of the probe block to below the metallic sealing ring and the track is formed with uncovered lateral extensions making electrical contact with the ring. This makes it possible to significantly prolong the service life of the measuring sensor.
摘要:
A process is proposed which serves to produce layer systems for gas sensors, the electrodes essentially being composed of a finely divided ceramic material and finely divided electron-conducting material. The process comprises adding stabilizer oxides to the electrode material in proportions above those necessary for full stabilization. As a result, a layer system having outstanding mechanical properties and high electrode load carrying capacity is obtained by a simple manufacturing process.
摘要:
A ceramic consisting substantially of Al.sub.2 O.sub.3 as ceramic support, ceramic cover layer and/or ceramic supporting structure for heating conductors is described, which is electrochemically stable, which, in other words, does not decompose on application of a heating voltage, even in long-term operation at temperatures above 600.degree.. Such a ceramic exhibits a very small alkali metal content, of less than 0.2% by weight Na.sub.2 O and K.sub.2 O respectively. Particularly favorable processing, in particular pressing properties are exhibited by such a ceramic if it has 2.5 to 10% by weight of barium silicate or strontium silicate fluxes, the proportions of Na.sub.2 O, K.sub.2 O, CaO and MgO together make up less than 1% by weight, and the BaO or SrO:SiO.sub.2 molar ratio is between 2:1 and 1:12.5. Such a ceramic with a BaO:SiO.sub.2 ratio of 2.6:1 parts by weight is electrochemically stable up to approximately 1400.degree. C., and at 1300.degree. C. still exhibits a bending strength of approximately 300 N/mm.sup.2.
摘要:
In order to obviate the necessity for design compromise of spark plugs with respect to their operating temperature, so that the ceramic insulator (18) of the spark plug will rapidly reach the temperature at which deposits thereon will inherently burn off (about 400.degree. C.-450.degree. C.) while not becoming so hot as to cause spurious glow ignition within the combustion chamber of an internal combustion (IC) engine, the end portion of the insulator is formed with a central opening (19/3) within which a metal core (24) is included which has a temperature coefficient of expansion such that, at temperatures below between 400.degree. C.-450.degree. C. it is spaced by a narrow gap (25) from the inner surface of the insulator (see FIG. 1) but, as the spark plug becomes hot, the gap 25 closes (FIG. 2), thereby providing good heat transmission from the insulator to the center electrode structure (21, 23, 24) and thereby maintaining the insulator at a temperature below that at which it might glow. Suitable materials for the center electrode are aluminum bronze, or other materials having a heat transmission characteristic of at least 90 W/mK. The insulator, preferably, has a higher-than-usual flux content so that, at low temperatures, its heat transmission characteristics are poor, to insure rapid heating to free combustion temperature of possible deposits.
摘要:
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.
摘要:
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.
摘要:
A sealing member is produced from form-pressed boron nitride powder, while adding an inorganic or organic binding agent. Such boron nitride powder is obtained during the machining of boron nitride blocks composed of hexagonal boron nitride. This powder can be fractionated according to particle size and the particle size desired for manufacturing the sealing member can be separated out.
摘要:
A sensor for determining an oxygen content of an exhaust gas of an internal combustion engine includes a flat-plate sensing element that is inserted in a gas-tight fashion via a hybrid seal in a ceramic shaped element that is arranged in a metal housing. The seal includes a powdered sealing packing, both placed around the sensing element in a recess at one end of the ceramic shaped element and a fusible glass seal located above the powdered sealing packing. The seal achieves gas-tight and gasoline-resistant isolation or immobilization of the sensing element in the ceramic shaped element.
摘要:
An electro-chemical measuring sensor (10) for determining the oxygen content of gases, in particular for determining the oxygen content in exhaust gases of internal combustion engines, with a potential-free disposed sensor element (14). The sensor element (14) has an oxygen-ion-conducting solid electrolyte body (23), preferably in the shape of a pipe or tube closed at one end, which has an exterior electrode (25) disposed on the exterior surface with a strip conductor (27) on the side toward the contact and also extending on the exterior surface, and which is inserted by means of a sealing ring (20) in a metal housing (11). The sensor element (14) has an electrically insulating layer (21) at least in the area of the sealing ring (20), which covers at least the strip conductor (27) in the direction toward the housing (11). The insulating layer (21) is formed from a mixture of a crystalline, non-metallic material and a glass-forming material. In the course of production the insulating layer (21) is subjected to a thermal treatment above the melting temperature of the glass-forming material, in the course of which the insulating layer (21) forms a glaze filled with the crystalline, non-metallic material.
摘要:
An electrochemical sensor for determining the oxygen concentration in gas mixtures is proposed. The sensor has a solid electrolyte (10) with oxygen ionic conductivity, which has a measuring electrode (11) that does not catalyze establishment of equilibrium of the gas mixture and is exposed to the gas mixture. The measuring electrode (11) contains platinum and bismuth. The effect of these materials is that the free oxygen contained in the gas mixture is preferentially adsorbed, without reacting with the other gas components such as CO and HC.