Abstract: A method of matching a firing profile of alumina material is disclosed as having a reference profile preparing step of preparing a reference profile of dissimilar material, an alumina profile preparing step of preparing an alumina profile of alumina material, a comparing step of comparing the reference profile and the alumina profile to determine whether to or not to perform correction on the alumina profile, and an adjusting step of adjusting the alumina material by increasing or decreasing a specific surface area of alumina raw material powder or by adding zirconia or magnesia to alumina material when a determination is made that the alumina profile needs to be corrected.

Abstract: Methods of manufacturing a ceramic sheet and a gas sensing element are disclosed. At least ceramic powder, a binder and a plasticizer are blended and mixed in slurry. The slurry is formed into unfired green sheets, on which paste is printed. Each of the unfired green sheets has porosity greater than 5%. In the manufacturing methods, the unfired green sheets are pressurized with a pressure of 10 MPa at a temperature above 60° C., after which the paste is printed on surfaces of the unfired green sheets. In the method of manufacturing the gas sensing element, a shielding layer, a porous diffusion resistance layer and the unfired green sheets for a sensing layer, a reference gas airspace forming layer and a heating layer are stacked to form a stacked ceramic body, whish is fired to obtain the gas sensing element.

Abstract: A method for manufacturing a ceramic stack is provided, which can suppress distortion, separation, cracking and the like that may be caused in plural types of ceramic sheets after being stacked and baked for integration. The method includes a step of obtaining a relation between volume rates of organic materials contained in the ceramic sheets and baking shrinkages of the sheets, resulting from baking the sheets at a predetermined temperature, a step of selecting a volume rate of organic materials for each of the ceramic sheets based on the relation obtained at the previous step, so that all the sheets may have substantially the same baking shrinkage as desired, a step of forming the plural types of ceramic sheets based on the volume rate selected at the previous step, and a step of stacking and baking for integration the plural types of ceramic sheets to fabricate a ceramic stack.

Abstract: A gas sensor element is designed to determine the concentration of a selected component contained in gas and includes a sensor cell. The sensor cell is equipped with two electrodes one of which is exposed to a gas chamber into which the gas flows from outside the gas sensor element. The electrodes connect with leads extending to external terminals exposed to the atmospheric air. One of the leads connecting with one of the electrodes exposed to the gas chamber is made of material which includes a mixture of a metallic composition and a ceramic composition and contains 7% or less by weight of the ceramic composition based on a total weight of the mixture. This results in a decrease in porosity of the lead, which reduces the intrusion of oxygen gas into the gas chamber, thereby enhancing the accuracy in determining the concentration of the selected component of the gas.

Abstract: A gas sensor element is provided which is designed to measure the concentration of hydrogen-containing gas accurately. The sensor element includes an oxygen pump cell working to keep the concentration of oxygen contained in measurement gasses entering a measurement gas chamber at a low concentration level and a hydrogen-containing gas measurement cell. The hydrogen-containing gas measurement cell is made up of a proton-conductive solid electrolyte body and a first and a second gas measurement electrode affixed to the proton-conductive solid electrolyte body. The first gas measurement electrode is exposed to the measurement gas chamber and serves to produce a signal between the first and second gas measurement electrodes as a function of the concentration of the hydrogen-containing gas.

Abstract: A fault detecting apparatus for a gas concentration sensor is provided. The apparatus includes a storage device and a fault detecting circuit. The storage device stores therein fault detectable conditions in which preselected different types of faults of the gas concentration sensor are allowed to be detected, respectively. The fault detecting circuit works to detect a selected one of the faults stored in said storage device. When one of the fault detectable conditions is encountered during operation of the gas concentration sensor, the fault detecting circuit initiates detection of a corresponding one of the faults based on an output of the gas concentration sensor, thereby enabling the fault detecting circuit to identify the type of one of the faults to be detected correctly.

Abstract: An air-fuel ratio sensor includes a sensor element inserted through a cylindrical housing for detecting an air-fuel ratio in an atmosphere of unburnt gas, and a measured gas side cover disposed on an end of the cylindrical housing so as to cover the sensor element and defining an inside chamber for storing therein a gas to be measured. The cover has a nested structure composed of a plurality of cup-shaped cover members disposed one inside another, each cover member having a gas inlet hole formed in a side wall thereof and a bottom hole formed in a bottom wall thereof. The gas inlet hole of an innermost one of the plural cover members that directly faces the sensor element is offset from an air-fuel ratio detecting portion of the sensor element toward the housing in an axial direction of the sensor.

Abstract: An electronic component substrate 1-1 includes an insulating base 10 and a flexible circuit board 20 mounted on the insulating base 10. The flexible circuit board 20 is a synthetic resin film provided thereon with terminal patterns 29 and a conductor pattern 25 whose surface is slidingly contacted with a slider. The insulating base 10 is a synthetic resin molded piece. The flexible circuit board 20 is insert-molded to the insulating base 10. The electronic component substrate 1-1 is produced by preparing the flexible circuit board 20 and first and second mold members 41 and 45 having a cavity C1 with a shape that corresponds to the external shape of the electronic component substrate 1-1. Then, the flexible circuit board 20 is accommodated in the cavity C1 between the first and second mold members 41 and 45, and a molten molding resin is filled into the cavity C1. After the filled molding resin has been solidified, the first and second mold members 41 and 45 are removed.

Abstract: A gas sensor includes a measurement gas chamber into which a measurement gas is introduced. An oxygen pumping cell adjusts an oxygen concentration in the measurement gas chamber. An oxygen monitor cell has a monitor electrode exposed in the measurement gas chamber. The monitor electrode has an oxidizing activity with respect to a specific component of the measurement gas. A sensor cell has a sensor electrode exposed in the measurement gas chamber. The sensor electrode has an oxidizing activity with respect to the specific component of the measurement gas which is lower than the oxidizing activity of the monitor electrode. An oxygen-ion current in the oxygen monitor cell is detected. An oxygen-ion current in the sensor cell is detected. A concentration of the specific component of the measurement gas is detected from a relation between the detected oxygen-ion currents in the oxygen monitor cell and the sensor cell.

Abstract: A highly accurate reduction resistant thermistor exhibiting stable resistance characteristics even under conditions where the inside of a metal case of a temperature sensor becomes a reducing atmosphere, wherein when producing the thermistor comprised of a mixed sintered body (M1 M2)O3.AOx, the mean particle size of the thermistor material containing the metal oxide, obtained by heat treating, mixing, and pulverizing the starting materials, is made smaller than 1.0 ?m and the sintered particle size of the mixed sintered body, obtained by shaping and firing this thermistor material, is made 3 ?m to 20 ?m so as to reduce the grain boundaries where migration of oxygen occurs, suppress migration of oxygen, and improve the reduction resistance.

Abstract: A gas sensor is disclosed which attains high response speed, low power consumption, superior water splash resistance and a little setting direction dependency and setting angle dependency. In this gas sensor, a measured gas room is provided inside an inner cover, and gas passage holes for leading a measured gas in are provided on side surfaces of the inner cover and an outer cover. The gas passage holes provided on the outer cover are positioned much closer to a top end side than the gas passage hole provided closest to the top end side in the inner cover. Partitions disposed extendedly in an axial direction of the gas sensor are provided between the outer cover and the inner cover.

Abstract: Thermistor elements composed mainly of a metal oxide sintered body are prepared by mixing a metal oxide precursor in a liquid phase to prepare a solution or slurry of the precursor. The precursor solution or slurry is sprayed to form droplet particles which are heat treated to form a thermistor raw material powder which powder is then molded and sintered into a shape to provide a metal oxide sintered body.

Abstract: A fault detecting apparatus for a gas concentration sensor is provided. The apparatus includes a storage device and a fault detecting circuit. The storage device stores therein fault detectable conditions in which preselected different types of faults of the gas concentration sensor are allowed to be detected, respectively. The fault detecting circuit works to detect a selected one of the faults stored in said storage device. When one of the fault detectable conditions is encountered during operation of the gas concentration sensor, the fault detecting circuit initiates detection of a corresponding one of the faults based on an output of the gas concentration sensor, thereby enabling the fault detecting circuit to identify the type of one of the faults to be detected correctly.

Abstract: A gas sensor is disclosed which attains high response speed, low power consumption, superior water splash resistance and a little setting direction dependency and setting angle dependency. In this gas sensor, a measured gas room is provided inside an inner cover, and gas passage holes for leading a measured gas in are provided on side surfaces of the inner cover and an outer cover. The gas passage holes provided on the outer cover are positioned much closer to a top end side than the gas passage hole provided closest to the top end side in the inner cover. Partitions disposed extendedly in an axial direction of the gas sensor are provided between the outer cover and the inner cover.

Abstract: An air-fuel ratio sensor includes a sensor element inserted through a cylindrical housing for detecting an air-fuel ratio in an atmosphere of unburnt gas, and a measured gas side cover disposed on an end of the cylindrical housing so as to cover the sensor element and defining an inside chamber for storing therein a gas to be measured. The cover has a nested structure composed of a plurality of cup-shaped cover members disposed one inside another, each cover member having a gas inlet hole formed in a side wall thereof and a bottom hole formed in a bottom wall thereof. The gas inlet hole of an innermost one of the plural cover members that directly faces the sensor element is offset from an air-fuel ratio detecting portion of the sensor element toward the housing in an axial direction of the sensor.

Abstract: A gas sensor element is provided which is made of a laminate of an oxygen pump cell, a sensor cell, an oxygen monitor cell, and a heater. The laminate has affixed thereto terminals for establishing transmission of signals between themselves and an external device and also has conductive lines formed on portions of an outer surface of the laminate which connect between the respective cells and the terminals. This structure ensures a required degree of insulation resistance between the heater and the cells and also eliminates the disadvantages of a conventional structure that electric disconnections between the terminals and the cells or cracks occur in the laminate.

Abstract: A gas sensor consists of a pump cell, a monitor cell, and a sensor cell. The sensor cell is supplied with power to produce a sensor cell current. The monitor cell is supplied with power to produce a monitor cell current. A sensor cell and a monitor cell current detector are disposed between a sensor cell electrode exposed to a gas cavity and a sensor cell power supply and between a monitor cell electrode exposed to the gas cavity and a monitor cell power supply, thereby enabling the sensor cell current and the monitor cell current to be measured without addition of electric noises arising from current components flowing from the monitor cell to the sensor cell and vice versa.

Abstract: A gas sensing element has a pump cell for pumping oxygen into or from a measuring-object gas chamber and a sensor cell for measuring the concentration of a specific gas contained in a measuring-object gas. The pump cell includes a measured gas side pump electrode exposed to the measuring-object gas stored in the measuring-object gas chamber.

Abstract: Provided is a multilayer gas sensing element having a high measurement accuracy and less susceptible to a leakage current. The element comprises an oxygen pump cell for adjusting an oxygen concentration in a measured gas chamber, a sensor cell for detecting a specified gas concentration in the measured gas chamber, and a heater for heating the cells up to an activating temperature. The heater includes a heat generator for generating heat when energized, a heater terminal provided externally and a heater lead for making electrical connection therebetween. When the electrical resistance value of the heat generator is taken as RH and the electrical resistance value of the heater lead is taken as RL, these values are set to satisfy the relationship of 1.5≦RH/RL.

Abstract: This invention provides a reducing-atmosphere-resistant thermistor element, the resistance of which does not greatly change even when the element is exposed to a reducing atmosphere, and which has high accuracy and exhibits excellent resistance value stability. The thermistor element has a construction in which an oxygen occlusion-release composition, having oxygen occlusion-release characteristics, such as CeO2 is dispersed in a composition containing a mixed sintered body (M1 M2)O3.AOx as a principal component. The oxygen occlusion-release composition emits absorbed oxygen in a reducing atmosphere and suppresses migration of oxygen from the composition constituting the element. Therefore, the resistance value does not greatly change even when the element is exposed to a reducing atmosphere, and the element can accurately detect the temperature for a long time. The present invention can thus provide a temperature sensor having high reliability.