An insulating separator of a gas sensor is formed to be dividable into a forward separator having a terminal disposition hole, and a rear separator having four terminal disposition holes. The insulating separator has a ventilation path formed between the forward separator and the rear separator. As a result, moisture and the like which enter the insulating separator from a forward side of the forward separator through the terminal disposition hole can be discharged outward of the insulating separator through the ventilation path. As a result, corrosion of metal terminals caused by entry of moisture can be reduced, whereby transmission of a sensor signal and application of current or voltage through the metal terminals can be appropriately implemented.

An electrochemical gas sensing element has a footprint of less than 5 mm×5 mm so the volume of electrolyte, the sizes of the electrodes, and the electrical interconnects are very small. This results in a fast stabilization after detecting gasses and enables rapid changes in bias voltage to target different gasses. The sensor body is ceramic, and the other components are stable at temperatures including solder reflow temperatures, thus allowing the use of conventional solder reflow techniques to mount the sensing element to a PCB. A sensor circuit is mounted on the sensing element body to detect the currents through the sensor electrode and digitally process the information, resulting in a more accurate analysis. The small size, low power consumption, and modularity allow the sensor element to be mounted in small handheld devices.

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.

A gas sensor includes a main pump cell, a storage unit that stores information about a zero point in a first correspondence relationship, where the first correspondence relationship is a linear correspondence relationship between the oxygen concentration in a measurement-object gas and the main pump current, an oxygen-concentration-detecting unit that detects the oxygen concentration in a measurement-object gas, based on a measured value p of the main pump current and the information about the zero point, and a measured-value-obtaining unit that performs a second control process and that obtains a measured value b1 at a measurement point B1 at which a known value of the oxygen concentration and the main pump current are relevant to each other with a measurement timing. The oxygen-concentration-detecting unit makes zero point correction such that a divergence of the zero point from the first correspondence relationship is corrected based on the measured value b1.

Provided is a flat plate-type oxygen sensor element. The flat plate-type oxygen sensor element according to an exemplary embodiment of the present invention includes: a first electrolyte layer having a sensing electrode exposed to a target gas; a second electrolyte layer on which a reference electrode is disposed; and a heating unit having a heating resistor surrounded by an insulating layer and disposed between the sensing electrode and the reference electrode, wherein the heating unit is disposed so that the heating resistor is located at a position ranging from 40 to 60% of a total height from an upper surface of the first electrolyte layer to a lower surface of the second electrolyte layer.

A protector includes an inside protector having an inside peripheral wall and a front end wall in a front end side thereof and a tubular outside protector which surrounds the inside protector. In an outside peripheral wall of the outside protector, a plurality of outside introducing ports through which an external part of the outside protector communicates with a gas separating chamber are formed at equal intervals along a circumferential direction. The outside introducing ports are formed at positions nearer to the front end side than positions where inside introducing ports of the inside protector are formed. The outside introducing ports extend in the circumferential direction of the outside peripheral wall and formed in shapes of lateral holes in which opening lengths in the circumferential direction are larger than opening lengths in the direction perpendicular to the circumferential direction.

An intake sensor includes a detection element, a heater, a housing, and a protector. The protector has two or more tubular portions spaced from one another in the radial direction. Of any two adjacent tubular portions, a second tubular portion on the outer side has tubular walls present in the penetration direction of first through holes of a first tubular portion on the inner side. Second through holes of the second tubular portion have an area equal to or greater than that of the first through hole. When the intake sensor is disposed in a model gas mixture of butane and air having air-fuel ratio of about 13, pressure of about 0.11 MPa, temperature of about 20° C., and flow rate of about 0 m/sec, and the heater heats the solid electrolyte member to the target temperature, no combustion flame is visually recognized on the outer surface of the protector.

A gas concentration detection device includes a pump cell, a sensor cell, a monitor cell, a sensor current detection unit detecting a current outputted by the sensor cell, a monitor current detection unit detecting a current outputted by the monitor cell, a voltage adjustment unit adjusting a pump cell voltage applied to the pump cell, and a sensitivity determination unit determining a gas sensitivity of at least one of the sensor cell or the monitor cell. The voltage adjustment unit changes the pump cell voltage from a target voltage into a detection voltage where the concentration of the residual oxygen supplied to the sensor cell and the monitor cell is increased. The sensitivity determination unit determines the gas sensitivity based on a detection current detected by at least one of the sensor current detection unit or the monitor current detection unit in accordance with the concentration of the residual oxygen.

A method of operating a sensor to detect an analyte in an environment, wherein the sensor includes a working electrode and circuitry in operative connection with the working electrode, includes performing a sensor interrogation cycle including applying electrical energy to the working electrode to generate a non-faradaic current, measuring a response to the generation of the non-faradaic current to determine a state of the sensor, and actively controlling the circuitry to dissipate the non-faradaic current.

Provided is a method of inspecting an assembly defect of a gas sensor in a mass-production process. The sensor element included in a second constituting member includes a heater therein and an electrode terminal for a heater in its surface, and the first constituting member includes a contact point member contacting the terminal in a state where the sensor element is inserted into its opening. A first heater resistance value before incorporated is measured to associate the resistance value with an identification information of the sensor element, a second heater resistance value is measured via a contact point member, in a state where the first and second constituting members are integrated with each other, to associate the resistance value with the identification information of the sensor element, and when a difference value between these resistance values associated with the identical identification information exceeds a threshold value, it is determined that an assembly defect occurs.