Applied Physics B

, Volume 109, Issue 3, pp 521–532 | Cite as

High-speed tunable diode laser absorption spectroscopy for sampling-free in-cylinder water vapor concentration measurements in an optical IC engine

  • O. Witzel
  • A. Klein
  • S. Wagner
  • C. Meffert
  • C. Schulz
  • V. Ebert


A novel, fiber-optic in situ laser hygrometer was developed to measure water vapor with microsecond time resolution directly inside an internal combustion (IC) engine. The instrument is intended for sampling-free quantification of recirculated exhaust gas in combustion engines. Direct tunable diode laser absorption spectroscopy was employed to allow absolute and self-calibrating H2O measurements. The compact and user-friendly instrument combines a fiber-coupled, 1.37 μm distributed feedback diode laser with kHz-fast, continuous wavelength scanning. Only small, typically 10 mm, optical access ports in the engine are needed. The new in situ hygrometer was tested via measurements in a motored optical research engine operated on ambient air, without any artificial humidification. Scanning the laser at 4 kHz resulted in a time resolution of 250 μs (i.e., 3° crank angle at 2,000 rpm), while the DC-coupled detector signals are digitized with a 4MSamples/s 16-bit data acquisition system. Absolute water vapor concentrations around 1 vol.% could be measured and quantified during the full compression stroke, i.e., over a pressure/temperature range of 0.07–0.52 MPa/300–500 K. Without any scan averaging or bandwidth filtering we could demonstrate signal-to-noise ratios between 51 (at p = 0.1 MPa) and 33 (at p = 0.4 MPa), which corresponds to H2O detection limits between 0.02 and 0.035 vol.% or length and bandwidth normalized detectivities of 285 and 477 ppb m Hz−½, respectively. Comparison of the dynamic H2O behavior during the compression stroke across several engine cycles and different operating conditions showed good reproducibility and absolute accuracy of the results, consistent with the boundary conditions, i.e., motored air operation. This new sensor therefore opens up new possibilities for engine cycle-resolved, calibration-free in situ AGR quantification and optimization in engine applications.


Combustion Chamber Internal Combustion Engine Compression Stroke Tunable Diode Laser Absorption Spectroscopy Vertical Cavity Surface Emit Laser 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.



The IGF project 15970 N/3 of the research association Forschungskuratorium Maschinenbau e.V.–FKM, Lyoner Straße 18, 60528 Frankfurt, was funded via the AiF within the scope of the program for the promotion of the Industrielle Gemeinschaftsforschung und -entwicklung (IGF) by the Federal Ministry of Economy and Technology on the basis of a decision of the German Federal Parliament. The authors also thank Dennis Bensing from the Institute for Combustion and Gasdynamics at the University of Duisburg-Essen for his work in the construction and operation of the engine.


  1. 1.
    N. Ladommatos, S. Abdelhalim, H. Zhao, The effects of exhaust gas recirculation on diesel combustion and emissions. Int. J. Engine Res. 1(1), 107–126 (2000)CrossRefGoogle Scholar
  2. 2.
    M.J. Cottereau, F. Grisch, J.J. Marie, CARS measurements of temperature and species concentrations in an IC engine. Appl. Phys. B 51(1), 63–66 (1990)ADSCrossRefGoogle Scholar
  3. 3.
    C. Schulz, A. Dreizler, V. Ebert, J. Wolfrum, Combustion diagnostics, in Springer Handbook of Experimental Fluid Mechanics, ed. by C. Tropea, A.L. Yarin, J.F. Foss (Springer, Berlin, 2007), pp. 1241–1315CrossRefGoogle Scholar
  4. 4.
    C. Schulz, V. Sick, Tracer-LIF diagnostics: quantitative measurement of fuel concentration, temperature and fuel/air ratio in practical combustion systems. Prog. Energy Combust. Sci. 31(1), 75–121 (2005)CrossRefGoogle Scholar
  5. 5.
    D.A. Rothamer, J.A. Snyder, R.K. Hanson, R.R. Steeper, Optimization of a tracer-based PLIF diagnostic for simultaneous imaging of EGR and temperature in IC engines. Appl. Phys. B 99(1–2), 371–384 (2009)ADSGoogle Scholar
  6. 6.
    H. Li, R.K. Hanson, J.B. Jeffries, Diode laser-induced infrared fluorescence of water vapour. Meas. Sci. Technol. 15, 1285–1290 (2004)ADSCrossRefGoogle Scholar
  7. 7.
    M. Cundy, T. Schucht, O. Thiele, V. Sick, High-speed laser-induced fluorescence and spark plug absorption sensor diagnostics for mixing and combustion studies in engines. Appl. Opt. 48(4), B94–B104 (2009)ADSCrossRefGoogle Scholar
  8. 8.
    E. Tomita, N. Kawahara, M. Shigenaga, A. Nishiyama, R.W. Dibble, In situ measurement of hydrocarbon fuel concentration near a spark plug in an engine cylinder using the 3.392 μm infrared laser absorption method: discussion of applicability with a homogeneous methane–air mixture. Meas. Sci. Technol. 14(8), 1350–1356 (2003)ADSCrossRefGoogle Scholar
  9. 9.
    L.A. Kranendonk, A.W. Caswell, A.M. Myers, S.T. Sanders, Wavelength-Agile Laser Sensors for Measuring Gas Properties in Engines (SAE International, Warrendale, PA) 2003-01-1116, Mar. 2003Google Scholar
  10. 10.
    L.A. Kranendonk, J.W. Walewski, T. Kim, S.T. Sanders, Wavelength-agile sensor applied for HCCI engine measurements. Proc. Combust. Inst. 30(1), 1619–1627 (2005)CrossRefGoogle Scholar
  11. 11.
    V. Ebert, J. Fitzer, I. Gerstenberg, M. Jochem, J. Martin, K.-U. Pleban, J. Wolfrum, Fast In situ Monitoring of O2 in a Full-scale Waste Incinerator with NIR-Diode-Lasers. Presented at the 18. Deutsch-Niederländischer Flammentag, vol. 1313, pp. 549–554 (1997)Google Scholar
  12. 12.
    X. Chao, J.B. Jeffries, R.K. Hanson, Absorption sensor for CO in combustion gases using 2.3 μm tunable diode lasers. Meas. Sci. Technol. 20(11), 115201 (2009)ADSCrossRefGoogle Scholar
  13. 13.
    T. Fernholz, H. Teichert, V. Ebert, Digital, phase-sensitive detection for in situ diode-laser spectroscopy under rapidly changing transmission conditions. Appl. Phys. B Lasers Opt. 75(2), 229–236 (2002)ADSCrossRefGoogle Scholar
  14. 14.
    G.B. Rieker, H. Li, X. Liu, J.T.C. Liu, J.B. Jeffries, R.K. Hanson, M.G. Allen, S.D. Wehe, P.A. Mulhall, H.S. Kindle, A. Kakuho, K.R. Sholes, T. Matsuura, S. Takatani, Rapid measurements of temperature and H2O concentration in IC engines with a spark plug-mounted diode laser sensor. Proc. Combust. Inst. 31(2), 3041–3049 (2007)CrossRefGoogle Scholar
  15. 15.
    G.B. Rieker, J.B. Jeffries, R.K. Hanson, Calibration-free wavelength-modulation spectroscopy for measurements of gas temperature and concentration in harsh environments. Appl. Opt. 48(29), 5546–5560 (2009)Google Scholar
  16. 16.
    B. Lins, R. Engelbrecht, B. Schmauss, Software-switching between direct absorption and wavelength modulation spectroscopy for the investigation of ADC resolution requirements. Appl. Phys. 106(4), 999–1008 (2012)Google Scholar
  17. 17.
    D.W. Mattison, J.B. Jeffries, R.K. Hanson, R.R. Steeper, S. De Zilwa, J.E. Dec, M. Sjoberg, W. Hwang, In-cylinder gas temperature and water concentration measurements in HCCI engines using a multiplexed-wavelength diode-laser system: sensor development and initial demonstration. Proc. Combust. Inst. 31(1), 791–798 (2007)CrossRefGoogle Scholar
  18. 18.
    J. Wolfrum, T. Dreier, V. Ebert, and C. Schulz, Laser-based combustion diagnostics in Encyclopedia of Analytical Chemistry, ed. by R.A. Meyers (Wiley, Chichester, 2006)Google Scholar
  19. 19.
    H. Teichert, T. Fernholz, V. Ebert, Simultaneous in situ measurement of CO, H2O, and gas temperatures in a full-sized coal-fired power plant by near-infrared diode lasers. Appl. Opt. 42(12), 2043–2051 (2003)ADSCrossRefGoogle Scholar
  20. 20.
    S. Wagner, B.T. Fisher, J.W. Fleming, V. Ebert, TDLAS-based in situ measurement of absolute acetylene concentrations in laminar 2D diffusion flames. Proc. Combust. Inst. 32(1), 839–846 (2009)CrossRefGoogle Scholar
  21. 21.
    P. Ortwein, W. Woiwode, S. Fleck, M. Eberhard, T. Kolb, S. Wagner, M. Gisi, V. Ebert, Absolute diode laser-based in situ detection of HCl in gasification processes. Exp. Fluids 49(4), 961–968 (2010)CrossRefGoogle Scholar
  22. 22.
    S. Hunsmann, K. Wunderle, S. Wagner, U. Rascher, U. Schurr, V. Ebert, Absolute, high resolution water transpiration rate measurements on single plant leaves via tunable diode laser absorption spectroscopy (TDLAS) at 1.37 μm. Appl. Phys. B Lasers Opt. 92(3), 393–401 (2008)ADSCrossRefGoogle Scholar
  23. 23.
    A.R. Awtry, B.T. Fisher, R.A. Moffatt, V. Ebert, J.W. Fleming, Simultaneous diode laser based in situ quantification of oxygen, carbon monoxide, water vapor, and liquid water in a dense water mist environment. Proc. Combust. Inst. 31(1), 799–806 (2007)CrossRefGoogle Scholar
  24. 24.
    A. Mangold, R. Wagner, H. Saathoff, U. Schurath, C. Giesemann, V. Ebert, M. Krämer, O. Möhler, Experimental investigation of ice nucleation by different types of aerosols in the aerosol chamber AIDA: implications to microphysics of cirrus clouds. Meteorol. Z. 14(4), 485–497 (2005)CrossRefGoogle Scholar
  25. 25.
    J.H. Lambert, Lamberts Photometrie: Photometria, Sive de Mensura Et Gradibus Luminis, Colorum Et Umbrae (1760), vol. 2. (Nabu Press, Charleston, 2010)Google Scholar
  26. 26.
    V. Ebert, J. Wolfrum, Absorption spectroscopy, in Techniques and Applications (Springer, München, 2001), pp. 227–265Google Scholar
  27. 27.
    G. Hohenberg, Der Verbrennungsverlauf—ein Weg zur Beurteilung des motorischen Prozesses. Presented at the 4. Wiener Motorensymposium, Düsseldorf, vol. 6, pp. 71–88 (1982)Google Scholar
  28. 28.
    S.T. Sanders, T. Kim, and J.B. Ghandhi, Gas Temperature Measurements During Ignition in an HCCI Engine (SAE International, Warrendale, PA) 2003-01-0744, Mar. 2003Google Scholar
  29. 29.
    S. Einecke, C. Schulz, V. Sick, Measurement of temperature, fuel concentration and equivalence ratio fields using tracer LIF in IC engine combustion. Appl. Phys. B Lasers Opt. 71, 717–723 (2000)ADSCrossRefGoogle Scholar
  30. 30.
    E.E. Whiting, An empirical approximation to the Voigt profile. J. Quant. Spectrosc. Radiat. Transfer 8(6), 1379–1384 (1968)ADSCrossRefGoogle Scholar
  31. 31.
    K. Levenberg, A method for the solution of certain problems in least squares. Q. Appl. Math. 2, 164–168 (1944)MathSciNetzbMATHGoogle Scholar
  32. 32.
    L.S. Rothman, I.E. Gordon, A. Barbe, D.C. Benner, P.F. Bernath, M. Birk, V. Boudon, L.R. Brown, A. Campargue, J.-P. Champion, The HITRAN 2008 molecular spectroscopic database. J. Quant. Spectrosc. Radiat. Transfer 110, 533–572 (2009)ADSCrossRefGoogle Scholar
  33. 33.
    S. Hunsmann, S. Wagner, H. Saathoff, O. Möhler, U. Schurath, V. Ebert, Messung der Temperaturabhängigkeit der Linienstärken und Druckverbreiterungskoeffizienten von H2O-Absorptionslinien im 1.4 μm-Band. VDI-Berichte 1959, 149–164 (2006)Google Scholar

Copyright information

© Springer-Verlag 2012

Authors and Affiliations

  • O. Witzel
    • 1
  • A. Klein
    • 1
  • S. Wagner
    • 1
    • 2
  • C. Meffert
    • 3
  • C. Schulz
    • 3
  • V. Ebert
    • 1
    • 2
  1. 1.Physikalisch-Technische BundesanstaltBraunschweigGermany
  2. 2.Center of Smart InterfacesTU DarmstadtDarmstadtGermany
  3. 3.IVG, Institute for Combustion and GasdynamicsUniversity of Duisburg-EssenDuisburgGermany

Personalised recommendations