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Title: Quantitative decoding of the response a ceramic mixed potential sensor array for engine emissions control and diagnostics

Abstract

The development of on-board sensors for emissions monitoring is necessary for continuous monitoring of the performance of catalytic systems in automobiles. We have fabricated mixed potential electrochemical gas sensing devices with Pt, La 0.8Sr 0.2CrO 3 (LSCO), and Au/Pd alloy electrodes and a porous yttria-stabilized zirconia electrolyte. The three-electrode design takes advantage of the preferential selectivity of the Pt + Au/Pd and Pt + LSCO pairs towards different species of gases and has additional tunable selectivity achieved by applying a current bias to the latter pair. Voltages were recorded in single, binary, and ternary gas streams of NO, NO 2, C 3H 8, and CO. We have also trained artificial neural networks to examine the voltage output from sensors in biased and unbiased modes to both identify which single test gas or binary mixture of two test gases is present in a gas stream as well as extract concentration values. We were then able to identify single and binary mixtures of these gases with accuracy of at least 98%. For determining concentration, the peak in the error distribution for binary mixtures was 5% and 80% of test data fell under <12% error. The sensor stability was also evaluated over themore » course of over 100 days and the ability to retrain ANNs with a small dataset was demonstrated.« less

Authors:
 [1];  [1];  [2];  [3];  [4]
  1. Univ. of New Mexico, Albuquerque, NM (United States). Center for MicroEngineered Materials
  2. ESL ElectroScience, King of Prussia, PA (United States)
  3. Sandia National Lab. (SNL-NM), Albuquerque, NM (United States). Advanced Materials Lab.
  4. Univ. of New Mexico, Albuquerque, NM (United States). Center for MicroEngineered Materials; Sandia National Lab. (SNL-NM), Albuquerque, NM (United States). Advanced Materials Lab.
Publication Date:
Research Org.:
Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)
Sponsoring Org.:
USDOE National Nuclear Security Administration (NNSA)
OSTI Identifier:
1399885
Report Number(s):
SAND2016-11543J
Journal ID: ISSN 0925-4005; PII: S0925400517306615
Grant/Contract Number:
AC04-94AL85000
Resource Type:
Journal Article: Accepted Manuscript
Journal Name:
Sensors and Actuators. B, Chemical
Additional Journal Information:
Journal Volume: 249; Journal Issue: C; Journal ID: ISSN 0925-4005
Publisher:
Elsevier
Country of Publication:
United States
Language:
English
Subject:
33 ADVANCED PROPULSION SYSTEMS; 54 ENVIRONMENTAL SCIENCES; mixed potential sensors; artificial neural networks; exhaust gas

Citation Formats

Tsui, Lok-kun, Benavidez, Angelica, Palanisamy, Ponnusamy, Evans, Lindsey, and Garzon, Fernando. Quantitative decoding of the response a ceramic mixed potential sensor array for engine emissions control and diagnostics. United States: N. p., 2017. Web. doi:10.1016/j.snb.2017.04.060.
Tsui, Lok-kun, Benavidez, Angelica, Palanisamy, Ponnusamy, Evans, Lindsey, & Garzon, Fernando. Quantitative decoding of the response a ceramic mixed potential sensor array for engine emissions control and diagnostics. United States. doi:10.1016/j.snb.2017.04.060.
Tsui, Lok-kun, Benavidez, Angelica, Palanisamy, Ponnusamy, Evans, Lindsey, and Garzon, Fernando. Thu . "Quantitative decoding of the response a ceramic mixed potential sensor array for engine emissions control and diagnostics". United States. doi:10.1016/j.snb.2017.04.060. https://www.osti.gov/servlets/purl/1399885.
@article{osti_1399885,
title = {Quantitative decoding of the response a ceramic mixed potential sensor array for engine emissions control and diagnostics},
author = {Tsui, Lok-kun and Benavidez, Angelica and Palanisamy, Ponnusamy and Evans, Lindsey and Garzon, Fernando},
abstractNote = {The development of on-board sensors for emissions monitoring is necessary for continuous monitoring of the performance of catalytic systems in automobiles. We have fabricated mixed potential electrochemical gas sensing devices with Pt, La0.8Sr0.2CrO3 (LSCO), and Au/Pd alloy electrodes and a porous yttria-stabilized zirconia electrolyte. The three-electrode design takes advantage of the preferential selectivity of the Pt + Au/Pd and Pt + LSCO pairs towards different species of gases and has additional tunable selectivity achieved by applying a current bias to the latter pair. Voltages were recorded in single, binary, and ternary gas streams of NO, NO2, C3H8, and CO. We have also trained artificial neural networks to examine the voltage output from sensors in biased and unbiased modes to both identify which single test gas or binary mixture of two test gases is present in a gas stream as well as extract concentration values. We were then able to identify single and binary mixtures of these gases with accuracy of at least 98%. For determining concentration, the peak in the error distribution for binary mixtures was 5% and 80% of test data fell under <12% error. The sensor stability was also evaluated over the course of over 100 days and the ability to retrain ANNs with a small dataset was demonstrated.},
doi = {10.1016/j.snb.2017.04.060},
journal = {Sensors and Actuators. B, Chemical},
number = C,
volume = 249,
place = {United States},
year = {Thu Apr 13 00:00:00 EDT 2017},
month = {Thu Apr 13 00:00:00 EDT 2017}
}

Journal Article:
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  • A mixed potential sensor using Au and Pt dense wire electrodes embedded between tape-casted layers of 8 mol% yttria stabilized zirconia (YSZ) was tested for application toward NH 3, NO, NO 2, C 3H 6 and C 3H 8. In single-gas testing, the sensor exhibited the highest response toward NH 3, while still exhibiting reasonably high sensitivity toward other interferent gases. We tested the sensor in a high-flow reactor at the National Transportation Research Center (NTRC) in order to simulate exhaust gas constituents and flow rates produced by lean-burn vehicles powered by Compression-Ignition Direct-Injection (CIDI), diesel engines. The sensor wasmore » characterized at 525 and 625°C for NH 3, CO, C 3H 6, C 3H 8, and NO x in a base gas composition of 10% O 2, 5% H 2O, and 5% CO 2 flowing at 15 slpm. The sensor exhibited fast response time equal to the response time of the system's switching valve (T90<0.6s). Furthermore, in simulations of overdosing a selective catalytic reduction (SCR) system, the sensor was able to selectively respond to 20ppm injections of NH 3 slip despite the presence of the interferent gas species at combined concentrations ten times higher than that of the NH 3. The laboratory sensor construct was transitioned to a pre-commercial, automotive stick sensor configuration that was demonstrated to retain the advantageous characteristics of the tape-cast device.« less
  • Here, a mixed-potential, electrochemical sensor platform is extended to NH 3 sensing by the introduction of a new gold alloy working electrode. A planar, pre-commercial NH 3 sensor utilized LANL’s controlled interface approach, and a Pd-Au alloy working electrode was tested in exhaust of a GM 1.9 L diesel engine downstream of a diesel oxidation catalyst through a slipstream arrangement. A fraction of the exhaust was pulled across the sensor with a pump at 20 L/min. In order to simulate NH 3 slip inside of a full SCR emissions control system, NH 3 was injected immediately upstream of the sensormore » using a calibrated mass flow controller. The sensor response quantitatively tracked the NH 3 as measured via Fourier transform infrared (FTIR) analyzer. A calibration curve was obtained in the exhaust from an ammonia staircase response with the engine running at steady-state engine conditions resulting in low background concentrations of NO x and HC (<20 ppm) during calibration. Exhaust gas recirculation (EGR) switching and sweeps were used to evaluate the NH 3 sensor response under different amounts of total background NO x. The calibration curve was used to directly compare the [NH 3] calculated from sensor response to the gas phase composition measured via FTIR. In general, there was excellent quantitative agreement between the sensor response and the actual NH 3 in the exhaust gas, and fast response time such that transients (<5 ppm) could be easily discerned from baseline. A LANL pre-commercial NO x sensor was tested simultaneously with the NH 3 sensor and the extent of cross-sensitivity between the two sensors will be discussed.« less
  • LANL mixed-potential electrochemical sensor (MPES) device arrays were coupled with advanced Bayesian inference treatment of the physical model of relevant sensor-analyte interactions. We demonstrated that our approach could be used to uniquely discriminate the composition of ternary gas sensors with three discreet MPES sensors with an average error of less than 2%. We also observed that the MPES exhibited excellent stability over a year of operation at elevated temperatures in the presence of test gases.