# US 2018/0321183 A1 · Sensor control apparatus and sensor control system

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- Number: US 2018/0321183 A1
- Document ID: US20180321183A1
- Status: Published application
- Kind: A1
- Application number: 16/033,106
- Filed: 2018-07-11
- Published: 2018-11-08
- Earliest claimed: 2015-03-09
- Assignees: Ngk Spark Plug Co., Ltd.
- Applicants: Ngk Spark Plug Co., Ltd.
- Inventors: Dai NISHIJIMA; Satoshi Teramoto
- Web page: https://patentgrep.com/patent/US20180321183A1

## CPC

- G01N 27/419: Measuring voltages or currents with a combination of oxygen pumping cells and oxygen concentration cells
- G01N 33/006: {Avoiding interference of water vapour with the gas to be measured}
- G01N: INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES (measuring or testing apparatus or processes other than immunoassay, involving enzymes or microorganisms C12M, C12Q)

## Abstract

A sensor control apparatus for a gas sensor which detects a particular gas component contained in a gas under measurement. In the case where humidity detection is performed using an electromotive-force-type gas sensor, a sensor control apparatus changes a target voltage of an electromotive force cell to a second target voltage for humidity detection and then to a third target voltage which is lower than a first target voltage which is a target voltage used for detecting the concentration of the particular gas component. In the case where humidity detection is performed using a limiting-current-type gas sensor, the sensor control apparatus changes the voltage applied to a pump cell to a second application voltage for humidity detection and then to a third application voltage which is lower than a first application voltage which is an application voltage used for detecting the concentration of the particular gas component.

## Claims

### Claim 1

A sensor control apparatus configured for connection to a gas sensor, the gas sensor including an oxygen pump cell having a solid electrolyte body, a first electrode formed on one surface of the solid electrolyte body, and a second electrode formed on the other surface of the solid electrolyte body and which detects a particular gas component contained in a gas under measurement, the sensor control apparatus comprising:
voltage application means for applying a first application voltage, a second application voltage, and a third application voltage, in this order, to the oxygen pump cell, the first application voltage being a voltage at which moisture contained in the gas under measurement does not substantially dissociate and which is used when the particular gas component is detected, the second application voltage being a voltage at which moisture contained in the gas under measurement dissociates, and the third application voltage being lower than the first application voltage;
pump current detection means for detecting pump current flowing through the oxygen pump cell; and
control means for detecting humidity of the gas under measurement based on a difference between the pump current when the first application voltage is applied to the oxygen pump cell and the pump current when the second application voltage is applied to the oxygen pump cell.

### Claim 2 (depends on 3)

The sensor control apparatus as claimed in claim 3, wherein the control means causes the pump current detection means to detect the pump current when a predetermined time has elapsed after the voltage applied to the oxygen pump cell has been changed from the third application voltage to the first application voltage by the voltage application means.

### Claim 3 (depends on 1)

A sensor control system comprising:
a gas sensor which includes an oxygen pump cell having a solid electrolyte body, a first electrode formed on one surface of the solid electrolyte body, and a second electrode formed on the other surface of the solid electrolyte body; and
the sensor control apparatus as claimed in claim 1.

### Claim 4 (depends on 2)

A sensor control system comprising:
a gas sensor which includes an oxygen pump cell having a solid electrolyte body, a first electrode formed on one surface of the solid electrolyte body, and a second electrode formed on the other surface of the solid electrolyte body; and
the sensor control apparatus as claimed in claim 2.