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US 6,332,965 B1Granted
Composite gas sensor
AssigneeDenso Corporation
InventorsTomio Sugiyama, Naoto Miwa, Masahiro Shibata, Hiromi Sano, Akio Tanaka
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Abstract
A composite gas sensor comprises a pump cell, a NOx sensor cell and an oxygen sensor cell. The NOx sensor cell is connected to a first ammeter and a constant power source to measure the NOx concentration of a sample gas. The pump cell is connected to a second ammeter and a variable power source to measure an air-fuel ratio of the sample gas. The oxygen sensor cell is connected to a voltmeter. A controller adjusts the variable power source to produce a constant value from the voltmeter.
Claims6
A composite gas sensor comprising:
- a plurality of solid electrolytic substrates defining at least part of a reference gas chamber and a sample gas chamber;
- a sample gas introducing passage introducing a sample gas into said sample gas chamber;
- a heater member for heating said solid electrolytic substrates;
- a pump cell having a pair of pumping electrodes for discharging oxygen gas contained in the sample gas introduced in said sample gas chamber by a predetermined amount, with one pumping electrode being located on a surface defining said sample gas chamber and the other pumping electrode being exposed to the sample gas not introduced in said sample gas introducing passage;
- a first sensor cell having a pair of oxygen sensing electrodes for generating an electromotive force indicative of an oxygen concentration in said sample gas chamber, with one oxygen sensing electrode being located in said sample gas chamber and the other oxygen sensing electrode being located in said reference gas chamber;
- a second sensor cell having a pair of NOx sensing electrodes for detecting a NOx concentration of the sample gas residing in said sample gas chamber after the pumping operation performed by said pumping cell, with one NOx sensing electrode being located in said sample gas chamber and the other NOx sensing electrode being located in said reference gas chamber;
- a third sensor cell having a pair of oxygen concentration sensing electrodes for generating an electromotive force indicative of an oxygen concentration of the sample gas residing in said sample gas chamber prior to said pumping operation performed by said pumping cell, with one oxygen concentration sensing electrode being located in said reference gas chamber and the other oxygen concentration sensing electrode being exposed to said sample gas not introduced in said sample gas introducing passage;
- said other pumping electrode and said other oxygen concentration sensing electrode being provided on the same surface of an outermost solid electrolytic substrate;
- and
- said other pumping electrode being disposed closer to a front end of said composite gas sensor than said other oxygen concentration sensing electrode.
7 more elements
Dependencies are inferred from the claim text.