Gas sensor element and gas sensor
AssigneeNGK Insulators, Ltd.
InventorsYusuke Watanabe, Daichi Ichikawa
Life of this patent
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Abstract
Provided is a gas sensor element or the like in which a diffusion mode of NOx reaching a measurement electrode is changed from molecular diffusion to a mode of diffusing while repeatedly colliding with a wall face of a sufficiently narrow flow path. In a gas sensor element according to one aspect of the present invention, a porous diffusion layer covering a measurement electrode has a porosity that is lower than the porosity of a leading end protection layer covering at least a face of an element substrate in which a gas inlet is open, and that is 5% or more and 25% or less.
Claims19
A gas sensor element comprising:
- an element substrate having a surface in which a gas inlet is open, and including an internal space into which a measurement target gas is introduced from the gas inlet;
- a leading end protection layer covering at least a face of the element substrate in which the gas inlet is open;
- a measurement electrode provided in the internal space and containing at least either silica or alumina;
- and
- a porous diffusion layer covering the measurement electrode and having a porosity that is 5% or more and 25% or less and is lower than a porosity of the leading end protection layer,
- wherein the porous diffusion layer has two faces in a thickness direction that are an internal face opposing the measurement electrode and an external face, and the internal face has a porosity higher than a porosity of the external face.
A gas sensor element comprising:
- an element substrate having a surface in which a gas inlet is open, and including an internal space into which a measurement target gas is introduced from the gas inlet;
- a leading end protection layer covering at least a face of the element substrate in which the gas inlet is open;
- a measurement electrode provided in the internal space and containing at least either silica or alumina;
- and
- a porous diffusion layer covering the measurement electrode and having a porosity that is 5% or more and 25% or less and is lower than a porosity of the leading end protection layer,
- wherein the measurement electrode and the porous diffusion layer are not in contact with each other, and
- wherein a distance between the measurement electrode and the porous diffusion layer is 0.15 mm or less.
A gas sensor element comprising:
- an element substrate having a surface in which a gas inlet is open, and including an internal space into which a measurement target gas is introduced from the gas inlet;
- a leading end protection layer covering at least a face of the element substrate in which the gas inlet is open;
- a measurement electrode provided in the internal space and containing at least either silica or alumina;
- and
- a porous diffusion layer covering the measurement electrode and having a porosity that is 5% or more and 25% or less and is lower than a porosity of the leading end protection layer,
- wherein the porous diffusion layer has two faces in a thickness direction that are an internal face opposing the measurement electrode and an external face, and the internal face has a porosity that is at least 10% higher than a porosity of the external face.
Dependencies are inferred from the claim text.