US 2001/0040104 A1 · Method for measuring component of a gaseous emission

Abstract

A modified universal exhaust gas oxygen sensor, referred to herein as a CEGA sensor, is provided which can be used to measure the concentration of a variety of components of a gaseous fuel emission including CO, CO2, O2, H2, and H2O. The CEGA sensor-employs at least one additional electrode on a ceramic substrate which possess a different catalytic activity relative to the electrodes that normally found on a UEGO sensor. The ceramic substrate may be made of any suitable ceramic and is preferably made of zirconia. The difference in catalytic activity between the additional electrode(s) and the electrodes native to the UEGO sensor create an oxygen gradient which enables a measure of combustion completeness to be calculated. In combination with an air/fuel ratio measured by the sensor, the concentrations of different components in the emission can be calculated. Several methods, devices and systems which can be used with various types of ceramic sensors including a CEGA sensor in order to improve their performance are also provided.

Claims18

Dependent claims

In a universal exhaust gas oxygen sensor (UEGO) for measuring properties of a gaseous emission comprising at least one oxygen pumping cell and a sensing cell in contact with a detection cavity, the pumping cell including a ceramic in gas communication with the detection cavity, a first electrode in contact with a first side of the ceramic inside the detection cavity, and a second electrode in contact with a second side of the ceramic outside the detection-cavity, a first voltage potential externally applied between the first and second electrodes for pumping oxygen across the ceramic into and out of the detection cavity, the first voltage potential being controlled by a second voltage potential across a third and fourth electrode of the sensing cell, an air/fuel ratio measurement of the gaseous emission being obtainable from the current passing between the first and second electrodes, the improvement comprising:

a fifth electrode which has a different catalytic activity than the first electrode positioned inside the detection cavity in contact with the pumping cell ceramic, a third voltage potential being externally applied between the fifth electrode and either the second electrode or a sixth electrode located on the second side of the pumping cell ceramic, the third voltage potential controlled by a fourth voltage formed between the first and fifth electrodes, a measure of combustion completeness being obtainable from a difference between the first and second voltage potentials.

A ceramic sensor for detecting components of a gaseous emission comprising:

a detection cavity;
a diffusion passage across which the gaseous emission enters the detection cavity;
an oxygen pumping cell defining a portion of the detection cavity formed of a ceramic substrate and having a first electrode in contact with a first side of the ceramic substrate within the detection cavity and a second electrode in contact with a second side of the ceramic substrate outside the detection cavity, an application of a first voltage potential between the first and second electrodes causing oxygen to be pumped into or out of the detection cavity across the ceramic substrate to maintain an oxygen concentration in the detection cavity at a target value;
a sensing cell defining a portion of the detection cavity formed of a ceramic substrate, the sensing cell including
a third electrode within the detection cavity,
a fourth electrode outside the detection cavity, a second voltage potential being formed between the third and fourth electrodes due to a difference in oxygen concentration across the third and fourth electrodes, the second voltage potential controlling the first voltage potential applied between the first and second electrodes, an air/fuel ratio measurement of the gaseous emission being obtainable from current passing between the first and second electrodes, and
a fifth electrode which has a different catalytic activity than the first electrode positioned inside the detection cavity in contact with the pumping cell ceramic, a third voltage potential being externally applied between the fifth electrode and either the second electrode or a sixth electrode located on the second side of the pumping cell ceramic, the third voltage potential controlled by a fourth voltage formed between the first and fifth electrodes, a measure of combustion completeness being obtainable from a difference between the first and second voltage potentials.

4 more elements

Dependencies are inferred from the claim text.

Method for measuring component of a gaseous emission

Life of this patent

Method for measuring component of a gaseous emission

Life of this patent

Abstract

Claims18