US 12,345,674 B2
Gas sensor and method of manufacture thereof
Shota Imada, Kariya (JP); Satoshi Suzuki, Kariya (JP); and Takumi Ushikubo, Kariya (JP)
Assigned to DENSO CORPORATION, Kariya (JP)
Filed by DENSO CORPORATION, Kariya (JP)
Filed on Dec. 21, 2021, as Appl. No. 17/557,853.
Application 17/557,853 is a continuation of application No. PCT/JP2020/023550, filed on Jun. 16, 2020.
Claims priority of application No. 2019-119478 (JP), filed on Jun. 27, 2019.
Prior Publication US 2022/0113276 A1, Apr. 14, 2022
Int. Cl. G01N 27/406 (2006.01); G01N 27/407 (2006.01); G01N 27/409 (2006.01)
CPC G01N 27/4067 (2013.01) [G01N 27/4072 (2013.01); G01N 27/4073 (2013.01); G01N 27/4077 (2013.01); G01N 27/409 (2013.01)] 7 Claims
OG exemplary drawing
 
1. A gas sensor provided with a sensor element comprising:
the sensor element including:
an element body having a solid electrolyte body provided with at least a pair of electrodes, and having an insulator laminated on the solid electrolyte body, with a heater embedded in the insulator,
a surface protective layer provided, exposed to a detection target gas, at an outermost surface position on a tip portion of the element body, extending along a longitudinal direction of the element body, and circumferentially covering a heating element of the heater with respect to a central axis along the longitudinal direction of the element body, and
an internal protective layer provided between the element body and the surface protective layer, and having a lower thermal conductivity or a higher average porosity than the surface protective layer; wherein
the internal protective layer includes a first protective layer portion, which faces the heater, with at least a base position of the first protective layer portion, in the longitudinal direction, being positioned closer to a tip end of the element body in the longitudinal direction than is a maximum temperature position of the element body in the longitudinal direction; and
the base position of the first protective layer portion, in the longitudinal direction, is positioned closer to a base end of the sensor element than is a tip position of the heating element such that the base position of the first protective layer portion is located between the maximum temperature position and the tip position of the heating element in the longitudinal direction.