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.
Similar content being viewed by others
References
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)
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)
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
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)
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)
H. Li, R.K. Hanson, J.B. Jeffries, Diode laser-induced infrared fluorescence of water vapour. Meas. Sci. Technol. 15, 1285–1290 (2004)
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)
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)
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
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)
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)
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)
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)
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)
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)
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)
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)
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)
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)
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)
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)
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)
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)
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)
J.H. Lambert, Lamberts Photometrie: Photometria, Sive de Mensura Et Gradibus Luminis, Colorum Et Umbrae (1760), vol. 2. (Nabu Press, Charleston, 2010)
V. Ebert, J. Wolfrum, Absorption spectroscopy, in Techniques and Applications (Springer, München, 2001), pp. 227–265
G. Hohenberg, Der Verbrennungsverlauf—ein Weg zur Beurteilung des motorischen Prozesses. Presented at the 4. Wiener Motorensymposium, Düsseldorf, vol. 6, pp. 71–88 (1982)
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
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)
E.E. Whiting, An empirical approximation to the Voigt profile. J. Quant. Spectrosc. Radiat. Transfer 8(6), 1379–1384 (1968)
K. Levenberg, A method for the solution of certain problems in least squares. Q. Appl. Math. 2, 164–168 (1944)
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)
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)
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.
Author information
Authors and Affiliations
Corresponding author
Rights and permissions
About this article
Cite this article
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
Received:
Revised:
Published:
Issue Date:
DOI: https://doi.org/10.1007/s00340-012-5225-0