Gas sensor element and gas sensor

Patent metadata

Field	Value
Publication number	US-11714062-B2
Application number	US-202016786082-A
Country	US
Kind code	B2
Filing date	Feb 10, 2020
Priority date	Aug 22, 2017
Publication date	Aug 1, 2023
Grant date	Aug 1, 2023

Abstract

A gas sensor element for detecting a specific gas component in a measured gas, comprising: an element body in the form of a long plate having a gas detection part at an end thereof on a distal end face side in a longitudinal direction; and a porous protective layer covering an outer periphery of the end on said end face side of the element body, wherein in a cross section including two adjacent ones of the end face and side faces connected to the end face, an outer surface of the protective layer facing an element corner where the two faces meet has a shape with a corner part, and a ratio of an assumed diameter of a water droplet contained in the measured gas in a use environment to an effective length of the corner part in the cross section is equal to or larger than 1.5.

First claim

What is claimed is:

1. A gas sensor element for detecting a specific gas component in a measured gas, the gas sensor element being housed in a cover body, and the gas sensor element comprising:
an element body in the form of a long plate having a gas detection part at an end thereof on an end face side in a longitudinal direction; and
a porous protective layer covering an outer periphery of the end on the end face side of the element body, wherein
an outer surface of the porous protective layer facing an element corner of the element body has a shape with a corner part,
the outer surface of the porous protective layer includes, in a cross section, two faces which are connected to each other with the corner part therebetween, the two faces of the porous protective layer being comprised of (i) an end face of the porous protective layer and (ii) one of side faces of the porous protective layer,
the end face of the porous protective layer is positioned at an end of the porous protective layer in the longitudinal direction,
the corner part has an effective length of the corner part in the cross section,
in the cross section including the two faces of the outer surface of the porous protective layer, an angle formed by the two faces of the outer surface of the porous protective layer that meet at the corner part is an acute angle,
the corner part is located on an extension line of a line that bisects the element corner,
the corner part has a water droplet contact surface including an intersection between the extension line of the line and the outer surface of the porous protective layer,
the effective length of the corner part is a distance between two ends of the water droplet contact surface in the cross section including the two faces,
the water droplet contact surface is flat, and
at least one of the end face and/or the one of the side faces of the outer surface of the porous protective layer is a curved concave face that expands outward from the element body as the curved concave face approaches the corner part, and the corner part protrudes outward from the end face and/or the one of the side faces to form the acute angle formed by the two faces of the outer surface of the porous protective layer.

2. The gas sensor element according to claim 1 , wherein the water droplet contact surface has shape change points respectively located in directions toward the two faces from the intersection, and the two ends of the water droplet contact surface are defined at the shape change points.

3. The gas sensor element according to claim 1 , wherein the effective length of the corner part is smaller than 1.2 mm and equal to or larger than 0.9 mm.

4. The gas sensor element according to claim 3 , wherein a ratio of the effective length of the corner part to a layer thickness of the porous protective layer at the corner part is equal to or smaller than 6 and equal to or larger than 2.

5. The gas sensor element according to claim 1 , wherein the corner part protrudes outward from at least one of the two faces of the outer surface of the porous protective layer facing the element corner.

6. The gas sensor element according to claim 1 , wherein the effective length of the corner part is 0.8 mm or more and smaller than 1.0 mm.

7. The gas sensor element according to claim 1 , wherein the porous protective layer has water repellency.

8. A gas sensor comprising the gas sensor element according to claim 1 , further comprising
a cylindrical housing supporting an outer periphery of the gas sensor element, wherein an end of the gas sensor element at which the porous protective layer is provided is housed in the cover body attached to one end of the cylindrical housing, and the measured gas is introduced into the cover body through a through hole provided in the cover body.

Assignees

• Denso Corp

Inventors

• Mouri Tomotaka
• Imada Shota
• Takeuchi Toru

Classifications

• G01N27/4077 Primary

  Means for protecting the electrolyte or the electrodes · CPC title

• G01N27/409

  Oxygen concentration cells · CPC title

• G01N27/4067

  Means for heating or controlling the temperature of the solid electrolyte · CPC title

• G01N27/4072

  characterized by the diffusion barrier · CPC title