US 4,298,573 AGranted

Device for detection of oxygen concentration in combustion gas

AssigneeNissan Motor Co., Ltd.

InventorTakeshi Fujishiro

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Abstract

A device suitable for use in engine exhaust gas to detect actual air/fuel ratio of air-fuel mixture supplied to the engine. The probe of the device has three electrodes. An oxygen ion conductive solid electrolyte occupies a space between the first and second electrodes, and a porous layer of similar solid electrolyte occupies a space between the second and third electrodes such that exhaust gas directly contacts the first and third electrodes and also contacts the second electrode through the porous solid electrolyte layer. At least one of the first and second electrodes, particularly the second, is made of a catalytic material, and the first and second electrodes serve as output terminals of the probe. Preferably the second and third electrodes are connected to a DC power supply to force a current to flow through the porous solid electrolyte layer to control oxygen partial pressure at the second electrode surface. By selectively determining catalysis of the first and second electrodes and/or the direction or intensity of the current, air/fuel ratios above, below and equal to a stoichiometric ratio can be detected.

Claims11

Dependent claims

A device for detecting the concentration of oxygen in a combustion gas thereby detecting an actual air/fuel ratio of an air-fuel mixture from which the combustion gas was produced, the device comprising a probe to be disposed in the combustion gas, said probe comprising:

a first electrode which is gas permeable;
a second electrode spaced from said first electrode;
an oxygen ion conductive solid electrolyte layer arranged to occupy the space between said first and second electrodes;
a third electrode which is gas permeably porous and spaced from said second electrode;
and
a gas permeably porous layer of an oxygen ion conductive solid electrolyte arranged to occupy the space between said second and third electrodes;
at least one of said first and second electrodes being made of a catalytic material which exhibits a catalytic action on oxidation reactions, said first, second and third electrodes being arranged such that the combustion gas directly contacts said first and third electrodes and comes into contact with said second electrode through said gas permeably porous layer occupying the space between said second and third electrodes, so that said probe can generate an electromotive force across said first and second electrodes as an indication of the concentration of oxygen in the combustion gas.

4 more elements

Dependencies are inferred from the claim text.

Facts

Application: 06/150,059Filed 15 May 1980
Priority: JP 54-6102319 May 1979
Granted: 3 Nov 1981
Term ends: Not estimatedThe source records don’t support an estimate.

Classification5 codes

G01N 27/4071
For investigating or analysing gases: using sensor elements of laminated structure
G01N 27/417
Systems: using cells , i.e. more than one cell and probes with solid electrolytes
Y10T 436/208339
Molecular oxygen: fuel/air mixture or exhaust gas analysis
G01N
Investigating or analysing materials by determining their chemical or physical properties

Family

No related US applications are recorded in the indexed filing history.

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