skip to main content


Title: Response characteristics of stable mixed-potential NH 3 sensors in diesel engine exhaust

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 sensor 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 phasemore » 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
 [1] ;  [2] ;  [1] ;  [2] ;  [2] ;  [2] ;  [1]
  1. Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
  2. Oak Ridge National Lab. (ORNL), Knoxville, TN (United States). National Transportation Research Center
Publication Date:
Report Number(s):
Journal ID: ISSN 2199-3629; VT0401000; CEVT010
Grant/Contract Number:
AC05-00OR22725; AC52-06NA25396
Accepted Manuscript
Journal Name:
Emission Control Science & Technology
Additional Journal Information:
Journal Volume: 3; Journal Issue: 1; Journal ID: ISSN 2199-3629
Research Org:
Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Fuels, Engines and Emissions Research Center (FEERC); Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). National Transportation Research Center (NTRC); Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
Sponsoring Org:
USDOE Office of Energy Efficiency and Renewable Energy (EERE)
Country of Publication:
United States
47 OTHER INSTRUMENTATION; sensor; electrochemical; mixed-potential; ammonia sensor; Energy Sciences; Electrochemical, Sensor, Ammonia, Mixed-potential
OSTI Identifier:
Alternate Identifier(s):
OSTI ID: 1406205