Ngk Spark Plug Company, Limited

Niterra Co., Ltd.

Yuji Oi

Satoshi Teramoto

Toshiya Matsuoka

Shigeki Mori

Takeshi Kawai

Tessho Yamada

Satoru Abe

Yuzo Higuchi

Junichiro Mitsuno

Hiroshi Inagaki

Norikazu Ieda

Hidetoshi Makino

Satoru Toda

Koji Ishibashi

A gas sensor control device having a DA conversion circuit configured to supply a pump current having a magnitude corresponding to an inputted digital signal to the pump cell, a reference electric potential generating circuit configured to keep an electric potential of the first pump electrode at a reference electric potential, a diagnostic resistance connected to the pump cell parallel to the pump cell, and an output part configured to output a signal relating to voltage applied to the diagnostic resistance when inputting an arbitrary digital signal to the DA conversion circuit in a situation in which oxygen ion conductivity does not occur in the pump cell to an external device.

Gas sensor control device, gas sensor control system, and gas sensor system

A sensor system (S) including a current DA converter () outputting a control current (Ip) of a sensor element (S), a control unit (C) generating a control current instruction value (Ipcmd) corresponding to magnitude of the control current and inputting this instruction value to the current DAC, an instruction value sequence generating unit () generating, instead of the control current instruction value, an inspection instruction value sequence (RChcmd) in which predetermined inspection current instruction values (Chcmd) inputted to the current DAC are arranged in order and by which failure of the current DAC can be detected, an inspection current detection unit () detecting an inspection current value (Ichv) of an inspection current (Ich) outputted from the current DAC, and a failure detection unit () detecting failure of the current DAC from an inspection current value sequence (RIchv) in which the inspection current values are arranged in order of detection.

Sensor system, and sensor system failure detecting method

A temperature sensor control apparatus includes a reference potential section, a driving potential section set to a driving electric potential, a temperature sensor configured to vary a resistance in accordance with a temperature, and disposed between the reference potential section and the driving potential section, a conduction path, two reference resistance elements each connected in series with the temperature sensor, a potential controlled point disposed in the conduction path between the reference resistance elements, a potential setting section configured to set an electric potential of the potential controlled point to the driving electric potential; and a resistance switching control section configured to control the potential setting section to switch the electric potential of the potential controlled point, and to switch each of the reference resistance elements to one of an energized state and a deenergized state.

Temperature sensor control apparatus

An oxygen concentration detection system including an oxygen sensor which outputs a plurality of types of measurement signals and anomaly detection means and modification means. The anomaly detection means detects a sensor anomaly by determining whether the respective levels of the plurality of types of measurement signals fall within predetermined ranges. When a sensor anomaly is not detected, the modification means outputs the plurality of types of measurement signals as is. When a sensor anomaly is detected, the modification means outputs at least one of the plurality of types of measurement signals at a level outside the corresponding range within which the level of the measurement signal varies in a normal state.

Oxygen concentration detection system and vehicle control system having the same

A constant current Iconst is applied to an electromotive force cell which is interposed between a gap (measurement chamber) of a fixed atmosphere and an oxygen reference chamber of a constant oxygen content, for measurement of a resistance value of the electromotive force cell, whereby the resistance value can be measured accurately irrespective of an oxygen content in an atmosphere to be measured by an oxygen sensor element or cell unit. The resistance value of the electromotive force cell is measured at a predetermined timing T2 after application of a current is started, so that a measure resistance value is free of a variation of a resistance value due to deterioration of porous electrodes of an electromotive force cell, such a variation being included in the measured resistance value in case the measurement is done by using an AC current, and therefore accurate measurement can be attained. A temperature control methods and a temperature control apparatus for an oxygen sensor, capable of detecting the temperature accurately without suspending measurement of an oxygen content for a long period of time are also provided. Further, a temperature control method and a temperature control apparatus for an oxygen sensor, capable of detecting not only the temperature of the electromotive force cell but the temperature of the pump cell by applying a current or voltage to the electromotive force cell are provided.

Temperature control for all range oxygen sensor

A method of detecting a deteriorated condition of a wide range air-fuel ratio sensor is provided. Firstly, a current is applied to an electromotive force cell to detect a voltage Vs0 across electrodes on opposite side surfaces of the cell. Application of the current is suspended, and a voltage drop Vsd1 across the electrodes is detected after lapse of a time ranging from 10 .mu.s to 1 ms after the application of the current is suspended. Based on the voltage drop Vsd1 is detected a first resistance value Rvs1 equated to the temperature of the electromotive force cell. Further, after lapse of a time ranging from 10 ms to 50 ms after the application of the current to the electromotive force cell is suspended, a voltage drop Vsd2 across the electrodes of the electromotive force cell is detected. Based on the voltage drop Vsd2 is detected a second resistance value Rvs2 equated to an internal resistance of the electromotive force cell including a resistance component resulting from deterioration. By comparison of the resistance values Rvs1 and Rvs2, the deteriorated condition of the wide range air-fuel ratio is detected. An apparatus for carrying out such a method is also provided.

Method of and apparatus for detecting a deteriorated condition of a wide

A method of detecting an activated condition of a wide range air-fuel ratio sensor is provided. With this method, application of a current to a heater is started idiately after an engine is started (S00). Then, a current Icp for pumping is passed through an electromotive force cell (S10). A lapse of a predetermined time Tin is waited for (S18). After a lapse of time Tin, a voltage Vs across both electrodes of the electromotive force cell is detected (S20) and labeled as Vs0 (S22). Then, application of Icp is suspended (S30) and a routine is held on standby until a time of 25 ms elapses (S35). At the point of time when the time of 25 ms has elapsed, the voltage across the electrodes on the opposite sides of the electromotive force cell is detected (S40) and labeled as Vs1 (S45). A resistance value Rs1 is calculated from Vs0, Vs1 and Icp (S50). The resistance value Rs1 is compared with a value Rss which has been prepared previously (S55) and it is judged, when Rs1 is smaller than Rss, that the electromotive force cell has been put into an activated condition. An apparatus for detecting an activated condition of a wide range air-fuel ratio sensor is also provided.

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Nagoya, Japan

Yuji Oi