Ngk Spark Plug Company, Limited

Satoru Abe

Yasuhiro Ishiguro

Akihiro Kobayashi

Junichiro Mitsuno

Chihiro Tomimatsu

Takayuki Sumi

Hidetoshi Makino

Satoshi Teramoto

Tomonori Uemura

Yuzo Higuchi

Tetsuya Ito

Koji Ishibashi

In a sensor control device which controls a sensor, a first filter unit extracts a first filtered signal obtained by attenuating a frequency component higher than a first cutoff frequency from a digital signal indicating a current-application control value for a pump current, and a second filter unit extracts a second filtered signal obtained by attenuating a frequency component higher than a second cutoff frequency from the first filtered signal. A cutoff frequency setting unit sets at least one of the first cutoff frequency and the second cutoff frequency such that the sensor control device can control at least two types of sensors.

Sensor control device and gas detection system

A sensor element drive circuit is a circuit including a plurality of semiconductor elements formed on a semiconductor substrate for realizing a current control function and a switching function. The current control function is a function of controlling the current flowing between electrodes such that the potential difference between electrodes becomes constant. The switching function is a function for switching between a connected state in which the electrodes are electrically connected to a sensor control apparatus and a cut-off state in which electrical continuity therebetween is broken. When one of an Ip+ terminal, a COM terminal, and a Vs+ terminal is determined to have an anomalous potential, the sensor control apparatus causes the sensor element drive circuit to perform switching from the connected state to the cut-off state, and connects the semiconductor substrate to a negative voltage lower than a ground potential applied to the sensor element drive circuit.

Sensor control apparatus

An anomaly determination apparatus determines an anomaly of a current control apparatus which supplies a control current to a control target and includes a current anomaly determination section. The current anomaly determination section is configured to compare a normal numerical range within which a state quantity changing with the control current falls in a particular state with a particular state quantity which is the state quantity corresponding to the control current generated by the control current generation section in the particular state, and determine that at least one of the reference resistor, the reference current generation section, and the control current generation section is in an anomalous state in the case where the particular state quantity has deviated from the normal numerical range. By using the current anomaly determination section, the anomaly determination apparatus can determine an anomaly of the current control apparatus.

Anomaly determination apparatus and control system

A gas concentration detection device for detecting a gas concentration using a limiting current type gas concentration sensor. In an application voltage line set to pass through a plurality of limiting current regions for different values of gas concentration, a ratio for lean is set as a ratio of change in current with respect to a change in voltage when an air/fuel ratio corresponding to the gas concentration is lean, and a ratio of rich different from the ratio for lean is set when the air/fuel ratio is rich.

Gas concentration detection device

A gas sensor control device for controlling a gas sensor, the gas sensor including a gas sensor element that includes a cell including a pair of electrodes and a solid electrolyte, the gas sensor control device including a circuit board connectable to the gas sensor. The circuit board has mounted thereon a voltage control unit mounted on the circuit board and configured to control a voltage developed across a pair of electrodes of the cell to a constant voltage; a temperature detecting unit mounted on the circuit board and configured to detect a temperature of the circuit board; and a voltage correcting unit mounted on the circuit board and configured to apply a correction voltage to the voltage control unit compensating for a temperature-dependent variation in the constant voltage based on the temperature detected by the temperature detecting unit.

Gas sensor control device

A sensor control circuit unit () includes a circuit board () which has opposite sides () and () facing in parallel with each other, and carries a signal detection circuit () for receiving a detection signal whose level is equal to or less than one &#x3bc;A and which changes in accordance with NOconcentration, a power supply circuit (), and a heater circuit () for controlling a heater. The power supply circuit () and the heater circuit () are mounted on one side of the circuit board () toward one side () of the opposite sides, and the signal detection circuit () is mounted in a mounting area on the other side of the circuit board () toward the other side () of the opposite sides, the mounting area being different from a mounting area of the circuits () and (). A ground conductor () connected to the ground is continuously formed on a surface of the circuit board () on which the signal detection circuit () is mounted such that the ground conductor () extends along at least the other of the opposite sides.

Sensor control unit and gas detection apparatus

There is provided a control device for a gas sensor. The gas sensor is formed with first and second oxygen pumping cells to define first and second measurement chambers. Under the control of the sensor control device, the first and second oxygen pumping cells effect oxygen pumping actions against the first and second measurement chambers, respectively. The sensor control device is configured to detect currents through the first and second oxygen pumping cells, calculate a correction coefficient by comparison of a detection value of the first oxygen pumping cell current at a known oxygen concentration period with a previously stored reference value, correct the first oxygen pumping cell current by the correction coefficient and determine the concentration of nitrogen oxide in the gas under measurement based on the corrected first oxygen pumping cell current and the detected second oxygen pumping cell current.

Growing community of inventors

Ichinomiya, Japan

Satoru Abe