US 8,506,780 B2Granted

Gas sensor

AssigneeNGK Insulators, Ltd.

InventorsMika Murakami, Hiroki Fujita, Sumiko Horisaka, Takashi Ito, Sang Jae Lee

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Abstract

A gas sensor includes an internal space, diffusion control part, pumping cell, and measuring cell. The diffusion control part communicates with the internal space and has a slit-like shape with a smaller thickness than that of the internal space. The pumping cell pumps out oxygen from the internal space when voltage is applied between a first electrode fowled on a surface of the internal space and a second electrode formed outside the internal space. The measuring cell measures a current flowing between a third and fourth electrodes when a voltage is applied between the third and fourth electrodes. The third electrode is formed in the diffusion control part, and can reduce an oxide gas component in a predetermined gas component to which a predetermined diffusion resistance has been applied by the diffusion control part. The fourth electrode is formed in a part different from the diffusion control part.

Claims10

Dependent claims

A gas sensor which has a sensor element constituted by an oxygen-ion conductive solid electrolyte as a main component and detects a predetermined gas component in a measurement gas, said sensor element comprising:

an internal space to which the measurement gas is introduced from the outside;
a diffusion control part in communication with said internal space in a lengthwise direction of said sensor element, said diffusion control part forming a slit-like space with a smaller thickness than that of said internal space, said diffusion control part applying a predetermined diffusion resistance to the measurement gas having been introduced to said internal space;
a pumping cell that pumps out oxygen existing in said internal space;
and
a measuring cell,
said pumping cell comprising:
a first electrode formed on a surface of said internal space;
and
a second electrode formed in a space different from said internal space,
said pumping cell pumping out oxygen existing in said internal space when a predetermined voltage is applied between said first electrode and said second electrode,
said measuring cell comprising:
a third electrode formed in said diffusion control part, said third electrode reducing an oxide gas component in said predetermined gas component to which said predetermined diffusion resistance has been applied by said diffusion control part;
and
a fourth electrode formed in a part different from said diffusion control part,
said measuring cell measuring a current flowing between said third electrode and said fourth electrode when a voltage is applied between said third electrode and said fourth electrode,
wherein a cross-sectional opening area of a part where said diffusion control part and said internal space communicate with each other is 0.005 mm2 or more and 0.3 mm2 or less, and
a distance from a boundary between said diffusion control part and said internal space to an end of said third electrode at a side opposite to said internal space is 0.3 mm or more 2.0 mm or less.

14 more elements

A sensor element of a gas sensor which detects a predetermined gas component in a measurement gas and which is constituted by an oxygen-ion conductive solid electrolyte as a main component, said sensor element comprising:

an internal space to which the measurement gas is introduced from the outside;
a diffusion control part in communication with said internal space in a lengthwise direction of said sensor element, said diffusion control part forming a slit-like space with a smaller thickness than that of said internal space, said diffusion control part applying a predetermined diffusion resistance to the measurement gas having been introduced to said internal space;
a pumping cell that pumps out oxygen existing in said internal space;
and
a measuring cell,
said pumping cell comprising:
a first electrode formed on a surface of said internal space;
and
a second electrode formed in a space different from said internal space,
said pumping cell pumping out oxygen existing in said internal space when a predetermined voltage is applied between said first electrode and said second electrode,
said measuring cell comprising:
a third electrode formed in said diffusion control part, said third electrode reducing an oxide gas component in said predetermined gas component to which said predetermined diffusion resistance has been applied by said diffusion control part;
and
a fourth electrode formed in a part different from said diffusion control part,
said measuring cell measuring a current flowing between said third electrode and said fourth electrode when a voltage is applied between said third electrode and said fourth electrode,
wherein a cross-sectional opening area of a part where said diffusion control part and said internal space communicate with each other is 0.005 mm2 or more and 0.3 mm2 or less, and
a distance from a boundary between said diffusion control part and said internal space to an end of said third electrode at a side opposite to said internal space is 0.3 mm or more 2.0 mm or less.

14 more elements

Dependencies are inferred from the claim text.

Facts

Application: 12/902,458Filed 12 Oct 2010
Priority: JP 2009-23589713 Oct 2009
Published: US 2011/0083490 A114 Apr 2011
Granted: 13 Aug 2013
Term ends: Not estimatedThe source records don’t support an estimate.

Classification3 codes

G01N 27/419
Using cells , i.e. more than one cell and probes with solid electrolytes: measuring voltages or currents with a combination of oxygen pumping…
G01N 27/4071
For investigating or analysing gases: using sensor elements of laminated structure
G01N
Investigating or analysing materials by determining their chemical or physical properties