Abstract: A gas concentration measuring apparatus is provided which works to calculate the concentration of a given gas component with enhanced accuracy. The gas concentration measuring apparatus 1 includes, a gas sensor 10 and a calculating portion 11. The gas sensor 10 is equipped with a pump cell 3, a monitor cell 4, and a sensor cell 5. The calculating portion 11 subtracts a monitor cell current Im that is a current flowing through the monitor cell 4 from a sensor cell current Is that is a current flowing through the sensor cell 5 to calculate the concentration of the given gas component in gas g. When calculating the concentration of the given gas component, the calculating portion 11 performs a correction operation to bring a value of the monitor cell current Im close to a value of an oxygen dependent current Iso that is a component of the sensor cell current Is which arises from the concentration of oxygen.

Abstract: A gas sensor is equipped with a solid electrolyte body, a pump electrode, a sensor electrode, and a heater. In the gas sensor, a region of the whole of a front end portion of a heater base in which a heating element is disposed is broken down into three regions: an intermediate region defined between a front end and a base end of the sensor electrode, a front end region located closer to a front end side than the intermediate region is, and a base end region located closer to a base end side than the intermediate region is. A resistance value per unit area of a heating element lying in the base end region and a resistance value per unit area of the heating element lying in the front end region is selected to be higher than that of the heating element lying in the intermediate region, thereby keeping the temperature of a region around the sensor electrode at a desired level even when the temperature of gas changes.

Abstract: A gas concentration detection apparatus is provided with a measuring gas chamber, a solid electrolyte body, a pump cell, a sensor cell, a pump cell controller and a sensor cell detection section. The pump cell controller applies an elimination voltage to the pump cell at a start-up point, before a gas concentration is detected. The water in the measuring gas chamber is decomposed and hydrogen is generated by application of the elimination voltage. Oxygen occluded in a sensor electrode of the sensor cell is removed by the hydrogen.

Abstract: A gas sensor device is equipped with the sensor cell, the pump cell, the inner void space, and the gas inlet. The sensor cell is created by a portion of the solid electrolyte body and a pair of sensor electrodes disposed on the solid electrolyte body. The pump cell is created by a portion of the solid electrolyte body and a pair of pump electrodes disposed on the solid electrolyte body. The inner void space faces the sensor electrode and the pump electrode. If a dimension of said gas inlet in a direction in which the measurement gas flows in the gas inlet is defined as L1, a sectional area of the gas inlet taken perpendicular to the direction of flow of the measurement gas in the gas inlet is defined as S1, a distance between the gas inlet and the sensor cell is defined as L2, and a sectional area of the inner void space taken perpendicular to a direction in which the pump cell and the sensor cell are aligned with each other is defined as S2, a relation of 1000?(L1/S1)×(L2/S2)?5000 is met.

Abstract: An SCU as a control device for the gas sensor (first and second NOx sensors) includes an applied voltage switching unit for switching an applied voltage of a pump cell when a deterioration detecting function is performed, and a deterioration rate calculation unit for calculating a deterioration rate of a sensor cell based on a slope during a transient change in an output of the sensor cell according to a switching of the applied voltage by the applied voltage switching unit.

Abstract: An exhaust gas purifying apparatus for an internal combustion engine, in which a NOx absorbing catalyst and a NOx concentration sensor for detecting a NOx concentration in exhaust gases of the engine, are provided in an exhaust passage of the engine. A rich spike for temporarily enriching the air-fuel ratio is performed, and an execution timing of the rich spike is determined based on a detected output from the NOx concentration sensor. Performing the rich spike is determined to be unnecessary during a reducing state period from the time the rich spike ends to the time a preset time period has elapsed, and is also determined to be unnecessary when a change tendency of the detected output is determined to be an output decreasing state where the detected output is decreasing.

Abstract: An apparatus for detecting particulate and a correction method of the apparatus for detecting particulate matter that detects particulate matter within a gas to be measured are provided. The correction method corrects the individual differences inevitably occurring during the manufacturing process of particulate matter detection sensors. The apparatus for detecting particulate matter includes an applied voltage correction means. The applied voltage correction means applies correction information acquired by the correction method to detection control.

Abstract: A NOx concentration measurement system has a NOx sensor, a detection section, a NH3 concentration estimation section and a calculation section. The NOx sensor measures a sum concentration c4 of a concentration of NOx (a concentration c1 of combustion derived NOx) in exhaust gas g, and a concentration of NO (concentration c3 of derived NO which has been derived from NH3) oxidized from NH3. The calculation section calculates the concentration c3 of derived NO by using a concentration c2 of NH3 contained in outside exhaust gas which is present around the NOx sensor, not inside of the NOx sensor, and at least one of an air fuel ratio A/F, a concentration of O2 and a concentration of H2O. The concentration c1 of the is calculated based on the sum concentration c4 and the concentration c3 of derived NO.

Abstract: A gas concentration measuring apparatus is provided which works to calculate the concentration of a given gas component with enhanced accuracy. The gas concentration measuring apparatus 1 includes, a gas sensor 10 and a calculating portion 11. The gas sensor 10 is equipped with a pump cell 3, a monitor cell 4, and a sensor cell 5. The calculating portion 11 subtracts a monitor cell current Im that is a current flowing through the monitor cell 4 from a sensor cell current Is that is a current flowing through the sensor cell 5 to calculate the concentration of the given gas component in gas g. When calculating the concentration of the given gas component, the calculating portion 11 performs a correction operation to bring a value of the monitor cell current Im close to a value of an oxygen dependent current Iso that is a component of the sensor cell current Is which arises from the concentration of oxygen.

Abstract: A particulate matter detection element includes a capacitance component disposed in parallel with a detected resistance RSEN. A direct current-power source that supplies a direct current (IDC) for particulate matter detection, and an alternating-current power source that supplies an alternating current (IAC) for disconnection detection are provided.

Abstract: A shielding part is formed on a detection part in a particulate matter detection element. The detection part has a pair of detection electrodes formed in a comb structure. A shielding layer is made of heat insulating material and formed on the detection part in order to shield a predetermined area having non-uniform electric field intensity. An area having uniform electric field intensity on the detection part is exposed only to exhaust gas as target detection gas when a predetermined voltage is supplied between the detection electrodes in order to detect electric characteristics of the detection part. This structure prevents the area other than the area having the uniform electric field intensity on the detection part from being exposed to the exhaust gas.

Abstract: An apparatus for detecting particulate and a correction method of the apparatus for detecting particulate matter that detects particulate matter within a gas to be measured are provided. The correction method corrects the individual differences inevitably occurring during the manufacturing process of particulate matter detection sensors. The apparatus for detecting particulate matter includes an applied voltage correction means. The applied voltage correction means applies correction information acquired by the correction method to detection control.

Abstract: A shielding part is formed on a detection part in a particulate matter detection element. The detection part has a pair of detection electrodes formed in a comb structure. A shielding layer is made of heat insulating material and formed on the detection part in order to shield a predetermined area having non-uniform electric field intensity. An area having uniform electric field intensity on the detection part is exposed only to exhaust gas as target detection gas when a predetermined voltage is supplied between the detection electrodes in order to detect electric characteristics of the detection part. This structure prevents the area other than the area having the uniform electric field intensity on the detection part from being exposed to the exhaust gas.

Abstract: In a PM detection sensor, a gas introduction hole is formed in a cover unit which surrounds a PM detection element. The gas introduction hole faces a detection part having detection electrodes of a comb structure. A projected part generated when an opening part of the gas introduction hole is projected on the detection part is within an inside area of the detection part. The projected area of the opening part of the gas introduction hole is positioned within the inside area having a uniform electric field intensity between the detection electrodes. The target detection gas is directly introduced through the gas introduction hole to the area having the uniform electric field intensity generated on the detection part. PM contained in the target detection gas is captured and accumulated on the area having the uniform electric field intensity but not on the area having non-uniform electric field intensity.

Abstract: A particulate matter detection element includes a capacitance component disposed in parallel with a detected resistance RSEN. A direct current-power source that supplies a direct current (IDC) for particulate matter detection, and an alternating-current power source that supplies an alternating current (IAC) for disconnection detection are provided.

Abstract: A PM-sensor having a sensor element is provided to an exhaust pipe. The sensor element has a concaved chamber on a particulate matter detection surface of an insulating substrate body, and a detection electrode formed on a bottom surface of the chamber. An insulating protecting layer covers an upper opening of the concaved chamber. The insulating protecting layer has a plurality of penetrating holes through which only particulate matter to be detected can passes.

Abstract: A gas sensor is equipped with a built-in ceramic heater. The gas sensor detects the concentration of a predetermined gas component contained in the exhaust gas. The ceramic heater has a heater base member made of ceramic, a heating element formed in the inside of the heater base material, and a pair of external electrode pads that is electrically connected to the output terminals for the outer leads. The external electrode pads, the heating element, and the heater leads are made of base metal. The outer surface of each external electrode pad is covered only with a dense protective film made of noble metal such as gold (Au), silver (Ag), platinum (Pt), rhodium (Rh), and palladium (Pd).

Abstract: A gas sensor is equipped with a built-in ceramic heater. The gas sensor detects the concentration of a predetermined gas component contained in the exhaust gas. The ceramic heater has a heater base member made of ceramic, a heating element formed in the inside of the heater base material, and a pair of external electrode pads that is electrically connected to the output terminals for the outer leads. The external electrode pads, the heating element, and the heater leads are made of base metal. The outer surface of each external electrode pad is covered only with a dense protective film made of noble metal such as gold (Au), silver (Ag), platinum (Pt), rhodium (Rh), and palladium (Pd).

Abstract: In an oxygen sensor for installation in the exhaust gas system of a vehicle for detecting a concentration of NOx in exhaust gas downstream from a catalytic converter, in which the exhaust gas is passed through a protective layer to an electrode disposed at one side of a solid electrolyte in a sensor element of the oxygen sensor, the protective layer is formed with a combination of values of thickness and porosity which provide improved sensitivity in detecting low levels of NOx in the exhaust gas.

Abstract: A gas sensor includes a sensing element, a housing, a metal cover, and an oxide layer. The sensing element generates a signal indicative of an oxygen concentration in a measurement gas. The housing holds therein the sensing element with a portion of the sensing element protruding outside of the housing. The metal cover surrounds the portion of the sensing element and is to be exposed the measurement gas. The metal cover has formed therein a gas passage through which the sensing element is also to be exposed to the measurement gas. The oxide layer is formed on at least a surface of the metal cover. With the oxide layer, during operation, at least the metal cover is prevented from being oxidized by the oxygen contained in the measurement gas. Consequently, the oxygen concentration in the measurement gas can be accurately determined based on the signal generated by the sensing element.