US 11,867,659 B2
Sensor element and gas sensor
Hitoshi Furuta, Nagoya (JP); Kentaro Kamada, Nagoya (JP); Akinori Kojima, Nagoya (JP); Satoshi Yamahara, Nagoya (JP); and Akihiro Hara, Nagoya (JP)
Assigned to NITERRA CO., LTD., Nagoya (JP)
Filed by NGK SPARK PLUG CO., LTD., Nagoya (JP)
Filed on Apr. 20, 2020, as Appl. No. 16/853,207.
Claims priority of application No. 2019-081474 (JP), filed on Apr. 23, 2019; and application No. 2019-219276 (JP), filed on Dec. 4, 2019.
Prior Publication US 2020/0340940 A1, Oct. 29, 2020
Int. Cl. G01N 27/409 (2006.01); G01N 27/41 (2006.01); G01N 27/406 (2006.01); G01N 27/407 (2006.01); G01M 15/10 (2006.01)
CPC G01N 27/409 (2013.01) [G01N 27/406 (2013.01); G01N 27/4071 (2013.01); G01N 27/4072 (2013.01); G01N 27/41 (2013.01); G01M 15/102 (2013.01)] 6 Claims
OG exemplary drawing
 
1. A sensor element of a stacked type extending in a direction of an axial line thereof, the sensor element comprising:
a measurement chamber;
a pump cell including a solid electrolyte, an inner electrode formed on a surface of the solid electrolyte and exposed to the measurement chamber, and an outer electrode formed on another surface of the solid electrolyte and disposed outside the measurement chamber, the pump cell being configured to adjust an oxygen concentration in the measurement chamber by pumping out and pumping in oxygen in a measurement target gas introduced into the measurement chamber;
a diffusion resistance portion disposed between outside and the measurement chamber and configured to adjust a diffusion rate of the measurement target gas introduced into the measurement chamber; and
a detection cell configured to measure a concentration of a specific gas in the measurement target gas after the adjustment of the oxygen concentration, wherein
the outer electrode is covered by a porous layer and is disposed in a hollow space surrounded by a first dense layer that has a gas non-permeable property and that prevents the outer electrode from coming into contact with the measurement target gas,
the hollow space is in communication with an air introduction hole that is open on a rear side relative to the diffusion resistance portion, and the outer electrode is exposed via the porous layer to air introduced through the air introduction hole, and
when viewed in a stacking direction, a heater is stacked on a side of the sensor element opposite to the first dense layer based on the solid electrolyte,
when viewed in the stacking direction, the first dense layer, the solid electrolyte, the diffusion resistance portion, and the heater are stacked in this order,
at least a part of the heater and the detection cell are contacted without a gap therebetween,
the porous layer is disposed in an opening of a second dense layer, the second dense layer being disposed between the first dense layer and a composite layer that includes the solid electrolyte and an insulating layer, and
side surfaces of the outer electrode are in direct physical contact with and embedded in the solid electrolyte.