US 12,352,722 B2
Gas sensor
Yusuke Watanabe, Nagoya (JP); and Taku Okamoto, Nagoya (JP)
Assigned to NGK INSULATORS, LTD., Nagoya (JP)
Filed by NGK INSULATORS, LTD., Nagoya (JP)
Filed on Mar. 14, 2023, as Appl. No. 18/183,425.
Claims priority of application No. 2022-043636 (JP), filed on Mar. 18, 2022.
Prior Publication US 2023/0296553 A1, Sep. 21, 2023
Int. Cl. G01N 27/407 (2006.01); G01N 27/41 (2006.01)
CPC G01N 27/4078 (2013.01) [G01N 27/4077 (2013.01); G01N 27/41 (2013.01)] 20 Claims
OG exemplary drawing
 
1. A gas sensor capable of sensing a predetermined gas component in a measurement gas, the gas sensor comprising:
a sensor element including an elongated planar base part formed of an oxygen-ion conductive solid electrolyte, and including a sensing part on a side of one end portion thereof; and
a casing in which the sensor element is contained and secured, wherein
the casing includes:
an outer tube having a reference gas space in which a reference gas is present and into which the other end portion of the sensor element protrudes; and
a seal member fit into an end portion of the outer tube to seal the reference gas space,
the sensor element includes:
at least one oxygen partial pressure adjustment internal space communicating with an inlet for the measurement gas disposed on a side of the one end portion under predetermined diffusion resistance;
a measurement internal space further communicating with the at least one oxygen partial pressure adjustment internal space;
an out-of-space pump electrode disposed at a location other than the at least one oxygen partial pressure adjustment internal space and the measurement internal space;
at least one inner electrode disposed to face the at least one oxygen partial pressure adjustment internal space;
a measurement electrode disposed to face the measurement internal space;
a first electrode lead portion including a first electrode lead and a first lead insulating layer, the first electrode lead extending from the out-of-space pump electrode to electrically connect an outside of the sensor element and the out-of-space pump electrode, the first lead insulating layer covering the first electrode lead;
a ceramic layer at least covering the first electrode lead portion; and
a second electrode lead portion including a second electrode lead and a second lead insulating layer, the second electrode lead extending from the measurement electrode to electrically connect the outside of the sensor element and the measurement electrode, the second lead insulating layer covering the second electrode lead,
a predetermined pump voltage is applied across the at least one inner electrode and the out-of-space pump electrode to pump in or out oxygen between the at least one oxygen partial pressure adjustment internal space corresponding to the at least one inner electrode and the outside of the sensor element,
a predetermined pump voltage is applied across the measurement electrode and the out-of-space pump electrode to pump in or out oxygen between the measurement internal space and the outside of the sensor element, and
A/B<1.00, where A (cm−1) is diffusion resistance of the first electrode lead portion, B (cm−1) is diffusion resistance of the second electrode lead portion.