Denso Corporation

Nippondenso Co., Ltd.

Tomoo Kawase

Eiichi Kurokawa

Toshiyuki Suzuki

Satoshi Hada

Satoshi Haseda

Mikiyasu Matsuoka

Takahito Masuko

Yohei Kawaki

Satoshi Nakamura

Koji Sugiura

Yukihiro Yamashita

Hiroshi Haraguchi

Toshiyuki Ishii

Kazuhiko Miura

Shingo Nakata

Mikio Ishihara

Ryozo Kayama

Takehiro Watarai

Yuki Murayama

Takao Mishima

Katsuhide Akimoto

Satoshi Hayashi

Katsuhiko Nakabayashi

Toru Katafuchi

Kenzi Kato

Akari Hasegawa

Shoki Shimizu

Tadakatsu Koyabu

Yoshinobu Takeuchi

Koji Jono

Daisuke Kojima

Yuuji Yamada

Satoshi Hudu

A particulate matter sensor includes a sensor element that includes a measurement member and a heater. An anomaly determiner performs determination that there is a break fault in a signal path of the measurement signal in response to both: (1) A first determiner, which determines whether a first measurement value of the measurement signal is higher than or equal to a predetermined normal determination threshold while the measurement voltage is applied between the measurement electrodes and the temperature of the measurement member is controlled at a first determination temperature, making a negative determination; and (2) A second determiner, which performs negative determination while the measurement voltage is applied between the measurement electrodes and the temperature of the measurement member is controlled within a predetermined temperature range that is higher than the first determination temperature and lower than a second determination temperature, making a negative determination.

Particulate matter sensor

In a gas sensor, a pump cell adjusts a concentration of oxygen in a gas chamber based of a pump cell supply voltage. A sensor cell detects a concentration of a specific gas in a detection target gas after the pump cell has adjusted the concentration of oxygen. In a sensor control unit, a voltage switching part adjusts the pump cell supply voltage to be supplied to the pump cell. A pump cell output control part adjusts a variation range of a pump cell output current of the pump cell before and after a voltage switching process of the pump cell supply voltage to be within a predetermined variation range. A deteriorated state detection part detects a deteriorated state ratio of the sensor cell based on variation of an output current of the sensor cell due to the voltage switching process performed by the voltage switching part.

Gas sensor control device

An Osensor includes a sensor element using a solid electrolyte layer and a pair of electrodes placed at a position to interpose the solid electrolyte layer, detects an exhaust gas from an internal combustion engine as an object of a detection, and outputs an electromotive force signal depending on an air-fuel ratio of the exhaust gas. The sensor element is connected with a constant current circuit supplying a constant current that is prescribed. A microcomputer calculates an element resistance, determines whether the air-fuel ratio is at least rich, lean, or stoichiometric, on the basis of a comparison between an electromotive force output of the electrogenic cell and a prescribed threshold. Further, the microcomputer controls the constant current supplied by the constant current circuit on the basis of the element resistance.

A honeycomb structure body is comprised of a honeycomb body, a pair of electrodes, a pair of electrode terminals and one or more slit sections. The honeycomb body is comprised of a cell formation section and an outer skin section. The outer skin section has a cylindrical shape and covers the cell formation section. The electrodes are formed on an outer peripheral surface of the outer skin section so that the electrodes face with to each other in a radial direction of the honeycomb structure body. Each electrode terminal is formed in an electrode terminal formation section on the corresponding electrode. One or more the slit sections are formed in at least one of an electrode terminal formation section and a circumferential outside section of the electrode terminal formation section.

Honeycomb structure body

A honeycomb body of a honeycomb structure is made of ceramic, and a plurality of electrodes are provided apart from one another on a surface of the honeycomb body. In the honeycomb body, energization is performed for each of a plurality of current paths Xa to Xc formed by the plurality of electrodes, thereby heating the honeycomb body. A controlling device detects heater current Ia, Ib, and IC that flow when a predetermined voltage is applied for each of the plurality of current paths Xa, Xb, and Xc, and controls an energization timing of each current path Xa to Xc based on the detection results.

Electrical heating catalyzer having honeycomb structure

A current detection resistance in a sensor control device is connected to a sensor element. The current flowing in the sensor element is detected through the current detection resistance. The current detection resistance is connected to an inverting amplification circuit for outputting an air/fuel output voltage to be transferred to a microcomputer. An offset setting circuit is connected to one input terminal of an operational amplifier in the inverting amplification circuit. The offset setting circuit is comprised of a switching element, a resistance connected in series to the switching element, and two dividing voltage resistances whose common node is connected to the resistance. The offset setting circuit generates and gives an offset to the A/F output voltage. The switching element is turned ON and OFF based on an offset switching signal transferred from the microcomputer.

Sensor control device

A sensor control apparatus includes an applied voltage control circuit connected to the positive terminal of a sensor element. The applied voltage control circuit includes a reference power supply and a noninverting amplifier circuit connected to the reference power supply. An AC power supply circuit, a buffer and a current measurement resistance are connected in series to the negative terminal of the sensor element with the current measurement resistance disposed between the AC power supply circuit and the sensor element. One terminal of the current measurement resistance, which is on the side opposite to the sensor element, is held at a reference voltage (center voltage of an AC voltage generated from the AC power supply circuit). Voltage at an intermediate point between the current measurement resistance and the sensor element is inputted via a low-pass filter to the noninverting amplifier circuit of the applied voltage control circuit.

Sensor control apparatus

The present invention provides, as one aspect, a signal processor for a gas sensor that is disposed in an exhaust passage of an internal combustion engine and senses concentration of a specific component in exhaust gas. The signal processor includes a calculation unit that performs moderation operation at every instant for a sensor output of the gas sensor, an evaluation unit that evaluates a degree of pressure variation impact on the sensor output caused in the exhaust passage, and a change unit that changes a mode of the moderation operation according to a result of the evaluation by the evaluation unit.

Signal processor for gas sensor

The gas sensor control apparatus develops a first voltage based on a first reference voltage at a negative terminal of a gas sensor device through a resistor and a second voltage based on a second reference voltage at a positive terminal of the gas sensor device. A controller samples through the resistor a sensor current, as created upon the development of the first and second voltage for measuring the concentration of gas. When the impedance of the gas sensor device is measured, the controller alternates the first voltage across the first reference voltage. The value (i.e., a zero-point) of the voltage applied to the gas sensor device when the sensor current is zero (i.e., 0 mA) depends upon the first and second reference voltages. The zero-point is corrected by regulating the second reference voltage to match an applying voltage characteristic to the gas sensor device correctly.

Gas sensor control apparatus designed to ensure accuracy of measurement in gas sensor

The degradation simulator is used for a gas sensor including a sensor element having a solid electrolyte layer and a pair of electrodes located opposite to each other across from the solid electrolyte layer, the sensor element outputting a sensor output signal having a value depending on concentration of a specific gas in the ambient gas. The degradation simulator includes a first setting function of enabling variably setting a time constant delay which appears on the sensor output signal when concentration of the specific gas changes, a second setting function of enabling variably setting a dead time delay which appears on the sensor output signal when concentration of the specific gas changes, and an adding function of adding at least one of the time constant delay and dead time delay to the sensor output signal in order to generate a pseudo-degraded sensor output signal in accordance with an external instruction.

Degradation simulator for gas sensor

A gas concentration measuring apparatus for use in air-fuel ratio control of automotive engines is designed to determine the concentration of oxygen within a wide and a narrow range using a sensor current flowing through a sensor element. The apparatus includes an amplifier circuit equipped with an operational amplifier and a plurality of amplifying resistors and a switch. The switch is responsive to a request signal to switch a relation in electrical connection between an operational amplifier and the amplifying resistors to distribute the amplifying resistors into an input resistor and a feedback resistor for the operational amplifier to change an amplification factor of the amplifier circuit. This results in a change in resolution of measurement of the concentration of oxygen, thereby ensuring enhanced accuracy in determining the concentration of oxygen in a selected one of the narrow and wide ranges.

Gas concentration measuring apparatus designed to enhance measurement accuracy in desired range

The gas sensor control apparatus is for controlling a gas sensor including a sensor element having a solid electrolyte layer, and first and second electrodes located on opposite sides of the solid electrolyte layer, the first electrode serving as a gas detecting electrode, the second electrode serving as a reference electrode, the sensor element generating, as a sensor output, a current flowing between the first and second electrodes having a value depending on concentration of a specific gas component contained in a gas under measurement. The gas sensor control apparatus includes a determination function of determining whether or not it is time for the gas sensor to start operation, and a control function of forcibly supplying oxygen from a side of the second electrode to a side of the first electrode on a temporary basis when a determination result of the first function becomes affirmative.

Gas sensor control apparatus

A gas concentration measuring apparatus for use in air-fuel ratio control of motor vehicle engines is provided which is designed to select or determine a correction factor for an output of an A/F sensor, as produced through a sensor control circuit, for compensating for errors in circuit characteristics of the A/F sensor and/or the sensor control circuit to ensure the accuracy of measurement in the apparatus.

Gas concentration measuring apparatus designed to compensate for output error

A gas concentration detection apparatus includes a series-connected combination of a sensor element and a resistor, with an AC voltage being applied to one of the outer terminals of that combination and with the other outer terminal being held at a fixed potential. A DC voltage signal at a level determined by an oxygen concentration that is detected by the sensor element, and an AC voltage signal at an amplitude determined by sensor element impedance and hence by the sensor element activation status, are extracted from the series-connected combination by respectively separate circuits which apply separately determined amplification factors.

Gas concentration detection apparatus having function for detecting sensor element activation status

A correction apparatus for correcting an output of an oxygen sensor installed in an exhaust pipe of an internal combustion engine to measure the concentration of oxygen contained in exhaust gas. The apparatus works to execute a fuel cut operation to bring the pressure in the exhaust pipe to the atmospheric pressure and enters an under-atmosphere correction mode to sample an output of the oxygen sensor and determine a correction factor compensating for a deviation of the sampled output from a reference value representing an actual concentration of oxygen. The apparatus also works to calculate the pressure in the exhaust pipe after start of the fuel cut and determine whether the under-atmosphere correction mode is to be entered or not based on the pressure of exhaust gas, thereby ensuring the accuracy in correcting the output of the oxygen sensor regardless of a variation in the pressure of exhaust gas.

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Aichi-ken, Japan

Tomoo Kawase