Topics in Catalysis

, Volume 59, Issue 10–12, pp 961–969 | Cite as

Review on Radio Frequency Based Monitoring of SCR and Three Way Catalysts

OriginalPaper

Abstract

Knowledge of the actual catalyst state plays a key role in automotive exhaust gas aftertreatment. The oxygen loading degree of three-way catalysts (TWC), the amount of stored ammonia in selective reduction catalysts (SCR), or the NOx loading degree in NOx storage catalysts (NSC) are important parameters. Today, they are determined indirectly and/or model-based, applying models that are typically calibrated by gas sensors installed up- and/or downstream of the catalysts. A novel approach to determine directly the catalyst state by microwaves (radio frequencies, rf) emerged recently. For this method, the catalyst housing serves as an electrical cavity resonator. As “sensor”, one or two simple antennas are mounted in the canning. The electrical properties of the honeycomb incl. coating change with gas loading, affecting either the resonance frequencies or the power transmission. Such contactless-obtained information is strongly correlated with the catalyst state as will be discussed here for TWC and SCR systems. This contribution reviews the progress in the past 3 years that exceeds by far the status of initial studies.

Keywords

On-board diagnostics (OBD) Exhaust gas aftertreatment Microwave cavity perturbation Radio frequency sensor Selective catalytic reduction (SCR) SCR ammonia storage Three-way catalyst (TWC) Oxygen storage (OSC) Lambda probe 

References

  1. 1.
    Moos R (2010) Catalysts as sensors—a promising novel approach in automotive exhaust gas aftertreatment. Sensors 10:6773–6787. doi:10.3390/s100706773 CrossRefGoogle Scholar
  2. 2.
    Sappok A, Bromberg L (2010) Loading and regeneration analysis of a diesel particulate filter with a radio frequency-based sensor. SAE paper 2010-01-2126. doi: 10.4271/2010-01-2126
  3. 3.
    Moos R, Wedemann M, Spörl M, Reiß S, Fischerauer G (2009) Direct catalyst monitoring by electrical means: an overview on promising novel principles. Top Catal 52:2035–2040. doi:10.1007/s11244-009-9399-6 CrossRefGoogle Scholar
  4. 4.
    Moos R, Beulertz G, Reiß S, Hagen G, Fischerauer G, Votsmeier M, Gieshoff J (2013) Overview: status of the microwave-based automotive catalyst state diagnosis. Top Catal 56:483–488. doi:10.1007/s11244-013-9980-x CrossRefGoogle Scholar
  5. 5.
    Masoudi M, Sappok A (2014) Soot (PM) Sensors. DieselNet Technology Guide. http://www.dieselnet.com/tech/dpf_soot_sensors.php. Accessed 07 Aug 2014
  6. 6.
    Nanjundaswamy H, Nagaraju V, Wu Y, Koehler E, Sappok A, Ragaller P, Bromberg L (2015) Advanced rf particulate filter sensing and controls for efficient aftertreatment management and reduced fuel consumption. SAE Technical Paper 2015-01-0996, doi: 10.4271/2015-01-0996
  7. 7.
    Sappok A, Bromberg L (2014) Radio frequency diesel particulate filter soot and ash level sensors: enabling adaptive controls for heavy-duty diesel applications. SAE Int J Commer Veh 7:468–477. doi:10.4271/2014-01-2349 CrossRefGoogle Scholar
  8. 8.
    Beulertz G, Fritsch M, Fischerauer G, Herbst F, Gieshoff J, Votsmeier M, Hagen G, Moos R (2013) Microwave cavity perturbation as a tool for laboratory in situ measurement of the oxidation state of three way catalysts. Top Catal 56:405–409. doi:10.1007/s11244-013-9987-3 CrossRefGoogle Scholar
  9. 9.
    Moos R, Fischerauer G (2015) Automotive catalyst state diagnosis using microwaves. Oil Gas Sci Technol 70:55–65. doi:10.2516/ogst/2013203 CrossRefGoogle Scholar
  10. 10.
    Fischerauer G, Spörl M, Gollwitzer A, Wedemann M, Moos R (2008) Catalyst state observation via the perturbation of a microwave cavity resonator. Frequenz 62:180–184. doi:10.1515/FREQ.2008.62.7-8.180 CrossRefGoogle Scholar
  11. 11.
    Dietrich M, Jahn C, Lanzerath P, Moos R (2015) Microwave based oxidation state and soot loading determination on gasoline particulate filters with three-way catalyst coating for homogenously operated gasoline engines. Sensors 15:21971–21988. doi:10.3390/s150921971 CrossRefGoogle Scholar
  12. 12.
    Birkhofer T, Hofmann P, Knezevic A, Moos R, Plog C, Schneider R (2003) Verfahren zur Erkennung des Zustands eines Katalysators mittels Mikrowellen. German Patent Specification DE 10358495 B4Google Scholar
  13. 13.
    Moos R, Spörl M, Hagen G, Gollwitzer A, Wedemann M, Fischerauer G (2008) TWC: lambda control and OBD without lambda probe—an initial approach. SAE paper 2008-01-0916, doi: 10.4271/2008-01-0916
  14. 14.
    Reiß S, Wedemann M, Spörl M, Fischerauer G, Moos R (2011) Effects of H2O, CO2, CO, and flow rates on the RF-based monitoring of three-way catalysts. Sensor Letters 9:316–320. doi:10.1166/sl.2011.1472 CrossRefGoogle Scholar
  15. 15.
    Reiß S (2012) Direkte Zustandssensorik von Automobilabgaskatalysatoren (Direct diagnosis of automotive exhaust gas catalysts), Doctoral thesis, Universität BayreuthGoogle Scholar
  16. 16.
    Möller R, Votsmeier M, Onder C, Guzzella L, Gieshoff J (2009) Is oxygen storage in three-way catalysts an equilibrium controlled process? Appl Catal B 91:30–38. doi:10.1016/j.apcatb.2009.05.003 CrossRefGoogle Scholar
  17. 17.
    Beulertz G, Votsmeier M, Herbst F, Moos R (2012) Replacing the lambda probe by radio frequency-based in-operando three-way catalyst oxygen loading detection. The 14th International Meeting on Chemical Sensors, IMCS 14, Nuremberg, Germany, 20–23 May 2012, pp 1426–1428, doi: 10.5162/IMCS2012/P2.2.7
  18. 18.
    Schödel S, Moos R, Votsmeier M, Fischerauer G (2014) SI-engine control with microwave-assisted direct observation of oxygen storage level in three-way catalysts. IEEE Trans Control Syst Technol 22:2346–2353. doi:10.1109/TCST.2014.2305576 CrossRefGoogle Scholar
  19. 19.
    Beulertz G, Votsmeier M, Moos R (2015) Effect of propene, propane, and methane on conversion and oxidation state of three-way catalysts: a microwave cavity perturbation study. Appl Catal B 165:369–377. doi:10.1016/j.apcatb.2014.09.068 CrossRefGoogle Scholar
  20. 20.
    Beulertz G, Votsmeier M, Moos R (2015) In operando detection of three-way catalyst aging by a microwave-based method: initial studies. Appl Sci 5:174–186. doi:10.3390/app5030174 CrossRefGoogle Scholar
  21. 21.
    Simons T, Simon U (2012) Zeolites as nanoporous, gas-sensitive materials for in situ monitoring of DeNOx-SCR. Beilstein J Nanotechnol 3:667–673. doi:10.3762/bjnano.3.76 CrossRefGoogle Scholar
  22. 22.
    Simon U, Franke ME (2000) Electrical properties of nanoscaled host/guest compounds. Microporous Mesoporous Mater 41:1–36. doi:10.1016/S1387-1811(00)00291-2 CrossRefGoogle Scholar
  23. 23.
    Franke ME, Simon U (2004) Solvate-supported proton transport in zeolites. Chem Phys Chem 5:465–472. doi:10.1002/cphc.200301011 Google Scholar
  24. 24.
    Pihl J, Daw S (2014) NH3 storage isotherms: a path toward better models of NH3 storage on zeolite SCR catalysts. Presentation at 2014 DOE Crosscut Workshop on Lean Emissions Reduction SimulationGoogle Scholar
  25. 25.
    Rauch D, Kubinski D, Cavataio G, Upadhyay D, Moos R (2015) Ammonia loading detection of zeolite SCR catalysts using a radio frequency based method. SAE Int J Engines 8:1126–1135. doi:10.4271/2015-01-0986 CrossRefGoogle Scholar
  26. 26.
    Rauch D, Kubinski D, Simon U, Moos R (2014) Detection of the ammonia loading of a Cu Chabazite SCR catalyst by a radio frequency-based method. Sens Actuators B Chemical 205:88–93. doi:10.1016/j.snb.2014.08.019 CrossRefGoogle Scholar
  27. 27.
    Rauch D, Albrecht G, Kubinski D, Moos R (2015) A microwave-based method to monitor the ammonia loading of a vanadia-based SCR catalyst. Appl Catal B 165:36–42. doi:10.1016/j.apcatb.2014.09.059 CrossRefGoogle Scholar
  28. 28.
    Deutschmann O, Grunwaldt JD (2013) Abgasnachbehandlung in mobilen Systemen: stand der Technik, Herausforderungen und Perspektiven. Chemie Ingenieur Technik 85(5):1–24. doi:10.1002/cite.201200188 CrossRefGoogle Scholar
  29. 29.
    Donovan S, Klein O, Dressel M, Holczer K, Griiner G (1993) Microwave cavity perturbation technique: part II: experimental scheme. Int J Infrared Millimeter Waves 14:2459–2487. doi:10.1007/BF02086217 CrossRefGoogle Scholar
  30. 30.
    Dietrich M, Rauch D, Porch A, Moos R (2014) A laboratory test setup for in situ measurements of the dielectric properties of catalyst powder samples under reaction conditions by microwave cavity perturbation: set up and initial tests. Sensors 14:16856–16868. doi:10.3390/s140916856 CrossRefGoogle Scholar
  31. 31.
    Dietrich M, Rauch D, Simon U, Porch A, Moos R (2015) Ammonia storage studies on H-ZSM-5 zeolites by microwave cavity perturbation: correlation of dielectric properties with ammonia storage. J Sens Sens Syst 4:263–269. doi:10.5194/jsss-4-263-2015 CrossRefGoogle Scholar

Copyright information

© Springer Science+Business Media New York 2016

Authors and Affiliations

  1. 1.Bayreuth Engine Research Center (BERC), Zentrum für Energietechnik (ZET)University of BayreuthBayreuthGermany
  2. 2.Umicore AG & Co. KGHanau-WolfgangGermany
  3. 3.Ford Research and Advanced EngineeringDearbornUSA

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