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

Abstract

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.

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References

  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)

    Article  Google Scholar 

  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)

    ADS  Article  Google Scholar 

  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. 1241–1315

    Chapter  Google Scholar 

  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)

    Article  Google Scholar 

  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)

    ADS  Google Scholar 

  6. H. Li, R.K. Hanson, J.B. Jeffries, Diode laser-induced infrared fluorescence of water vapour. Meas. Sci. Technol. 15, 1285–1290 (2004)

    ADS  Article  Google Scholar 

  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)

    ADS  Article  Google Scholar 

  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)

    ADS  Article  Google Scholar 

  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. 2003

  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)

    Article  Google Scholar 

  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)

  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)

    ADS  Article  Google Scholar 

  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)

    ADS  Article  Google Scholar 

  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)

    Article  Google Scholar 

  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. 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. 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)

    Article  Google Scholar 

  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)

  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)

    ADS  Article  Google Scholar 

  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)

    Article  Google Scholar 

  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)

    Article  Google Scholar 

  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)

    ADS  Article  Google Scholar 

  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)

    Article  Google Scholar 

  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)

    Article  Google Scholar 

  25. J.H. Lambert, Lamberts Photometrie: Photometria, Sive de Mensura Et Gradibus Luminis, Colorum Et Umbrae (1760), vol. 2. (Nabu Press, Charleston, 2010)

  26. V. Ebert, J. Wolfrum, Absorption spectroscopy, in Techniques and Applications (Springer, München, 2001), pp. 227–265

  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)

  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. 2003

  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)

    ADS  Article  Google Scholar 

  30. E.E. Whiting, An empirical approximation to the Voigt profile. J. Quant. Spectrosc. Radiat. Transfer 8(6), 1379–1384 (1968)

    ADS  Article  Google Scholar 

  31. K. Levenberg, A method for the solution of certain problems in least squares. Q. Appl. Math. 2, 164–168 (1944)

    MathSciNet  MATH  Google Scholar 

  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)

    ADS  Article  Google Scholar 

  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 

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Acknowledgments

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.

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Witzel, O., Klein, A., Wagner, S. et al. High-speed tunable diode laser absorption spectroscopy for sampling-free in-cylinder water vapor concentration measurements in an optical IC engine. Appl. Phys. B 109, 521–532 (2012). https://doi.org/10.1007/s00340-012-5225-0

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  • DOI: https://doi.org/10.1007/s00340-012-5225-0

Keywords

  • Combustion Chamber
  • Internal Combustion Engine
  • Compression Stroke
  • Tunable Diode Laser Absorption Spectroscopy
  • Vertical Cavity Surface Emit Laser