Abstract

A simple optical multichannel analyzer consisting of SIT vidicon camera, videotape recorder, and video digitizer was used to record coherent anti-Stokes Raman scattering N2 spectra for temperature measurements inside a firing internal combustion engine. A high-resolution spectrum was recorded from each engine cycle at a 10-Hz repetition rate. Thousands of spectra were rapidly stored in inexpensive nonvolatile memory (videotape) to be digitized and analyzed later for the generation of temperature histograms. In addition to this spectroscopic application, the same equipment can be used for fluid dynamic and combustion imaging experiments.

© 1984 Optical Society of America

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References

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  1. P. D. Maker, R. W. Terhune, Phys. Rev. A 137, 801 (1965).
  2. P. R. Regnier, J.-P. E. Taran, Appl. Phys. Lett. 23, 240 (1973).
    [CrossRef]
  3. For example, S. A. J. Druet, J.-P. E. Taran, Prog. Quantum Electron. 7, 1 (1981).
    [CrossRef]
  4. I. A. Stenhouse, D. R. Williams, J. B. Cole, M. D. Swords, Appl. Opt. 18, 3819 (1979).
    [PubMed]
  5. D. Klick, K. A. Marko, L. Rimai, Appl. Opt. 20, 1178 (1981).
    [CrossRef] [PubMed]
  6. L. A. Rahn, S. C. Johnston, R. L. Farrow, P. L. Mattern, Temperature, Vol. 5 (American Institute of Physics, New York, 1982), Part 1, p. 609.
  7. A. C. Eckbreth, Combust. Flame 39, 133 (1980).
    [CrossRef]
  8. M. Pealat, J.-P. E. Taran, F. Moya, Opt. Laser Technol. 12, 21 (1980).
    [CrossRef]
  9. W. B. Roh, P. W. Schreiber, J.-P. E. Taran, Appl. Phys. Lett. 29, 174 (1976).
    [CrossRef]
  10. D. Klick, K. A. Marko, L. Rimai, Temperature, Vol. 5 (American Institute of Physics, New York, 1982), Part 1, p. 615.
  11. A. C. Eckbreth, G. M. Dobbs, J. H. Stufflebeam, P. A. Tellex, AIAA Paper No. 83-1294 (1983).
  12. K. A. Marko, L. Rimai, Opt. Lett. 4, 211 (1979).
    [CrossRef] [PubMed]
  13. L. C. Davis, K. A. Marko, L. Rimai, Appl. Opt. 20, 1685 (1981).
    [CrossRef] [PubMed]
  14. Cyclic variation in pressure is seen in all IC engines, including ours. Cyclic variation in temperature was reported by us in Ref. 10. Time of flame arrival was measured by the deflection of an expanded He–Ne beam focused in the chamber center. Variations of ±3 CA° in this time were seen and were correlated with cyclic variations in peak pressure. All these variations were greatly reduced in the study of Ref. 6 by inducing an unrealistically large swirl.
  15. Viewing the pump beam spectrum with the high-resolution spectrometer, we see three peaks (modes) with the etalon detuned. Tuning the etalon suppresses the sidebands far below the central peak, giving essentially single-mode operation. The etalon is tuned before each run and remains tuned for the duration of a run.
  16. A set of simultaneous engine and reference spectra were acquired with the engine filled with Ideally, the divided spectrum CO2. for each pulse would be flat, but the normalization is not perfect and noise remains. Integrating spectral passbands of these normalized spectra as we would for a temperature determination, we found an effect on temperature due to the imperfect normalization of ±80 K at 2000 K. Thus, imperfect normalization accounts in large part for the imprecision of CARS temperature readings in a stable burner reported earlier by us.10An alternative normalization procedure has been employed11 which assumes that the overall dye laser shape is repeatable. To test this procedure, we normalized the set of engine spectra described above with the average reference spectrum and found only a 20% rise in the temperature imprecision that would be due to imperfect normalization and dye laser noise. However, for some pulses there were regions of the engine spectrum that poorly matched the average reference spectrum. If individual reference spectra are not used for normalization, the most stable region of the dye laser spectral profile should be centered over the region of interest, and a method for deleting spectra generated by distorted dye profiles should be employed.11
  17. H. Staerk, R. Mitzkus, H. Meyer, Appl. Opt. 20, 471 (1981).
    [CrossRef] [PubMed]
  18. G. Liesegang, P. D. Smith, Appl. Opt. 21, 1437 (1982).
    [CrossRef] [PubMed]
  19. R. K. Chang, M. B. Long, Topics in Applied Physics, Vol. 50 (Springer, Berlin, 1982), Chap. 3, p. 179.
    [CrossRef]
  20. For most of the engine cycle, almost every pulse yields a usable spectrum. Only from 0–6 CA° are the majority of spectra deflected, coinciding with the fluctuating time of flame arrival.14 It is clear that the temperature histograms acquired during this short period might be biased (e.g., more hot spectra than cold spectra might be deflected), and that the histograms may have more to do with cyclic variation in flame arrival than with flame structure.
  21. L. A. Rahn, R. L. Farrow, P. L. Mattern, presented at the 8th International Conference on Raman Spectroscopy, Bordeaux, France, Sept. 1982.
  22. R. J. Hall, Opt. Eng. 22, 322 (1983).
    [CrossRef]
  23. The equivalent analog operation could be performed with the signal from a standard camera turned at 90° so that the electron beam scans along spectral lines.
  24. G. L. Switzer, L. P. Goss, Temperature, Vol. 5 (American Institute of Physics, New York, 1982), Part 1, p. 583.
  25. A. C. Eckbreth, Appl. Opt. 22, 2118 (1983).
    [CrossRef] [PubMed]
  26. L. Rimai, K. A. Marko, Opt. Lett. 7, 328 (1982).
    [CrossRef] [PubMed]

1983 (2)

1982 (2)

1981 (4)

1980 (2)

A. C. Eckbreth, Combust. Flame 39, 133 (1980).
[CrossRef]

M. Pealat, J.-P. E. Taran, F. Moya, Opt. Laser Technol. 12, 21 (1980).
[CrossRef]

1979 (2)

1976 (1)

W. B. Roh, P. W. Schreiber, J.-P. E. Taran, Appl. Phys. Lett. 29, 174 (1976).
[CrossRef]

1973 (1)

P. R. Regnier, J.-P. E. Taran, Appl. Phys. Lett. 23, 240 (1973).
[CrossRef]

1965 (1)

P. D. Maker, R. W. Terhune, Phys. Rev. A 137, 801 (1965).

Chang, R. K.

R. K. Chang, M. B. Long, Topics in Applied Physics, Vol. 50 (Springer, Berlin, 1982), Chap. 3, p. 179.
[CrossRef]

Cole, J. B.

Davis, L. C.

Dobbs, G. M.

A. C. Eckbreth, G. M. Dobbs, J. H. Stufflebeam, P. A. Tellex, AIAA Paper No. 83-1294 (1983).

Druet, S. A. J.

For example, S. A. J. Druet, J.-P. E. Taran, Prog. Quantum Electron. 7, 1 (1981).
[CrossRef]

Eckbreth, A. C.

A. C. Eckbreth, Appl. Opt. 22, 2118 (1983).
[CrossRef] [PubMed]

A. C. Eckbreth, Combust. Flame 39, 133 (1980).
[CrossRef]

A. C. Eckbreth, G. M. Dobbs, J. H. Stufflebeam, P. A. Tellex, AIAA Paper No. 83-1294 (1983).

Farrow, R. L.

L. A. Rahn, S. C. Johnston, R. L. Farrow, P. L. Mattern, Temperature, Vol. 5 (American Institute of Physics, New York, 1982), Part 1, p. 609.

L. A. Rahn, R. L. Farrow, P. L. Mattern, presented at the 8th International Conference on Raman Spectroscopy, Bordeaux, France, Sept. 1982.

Goss, L. P.

G. L. Switzer, L. P. Goss, Temperature, Vol. 5 (American Institute of Physics, New York, 1982), Part 1, p. 583.

Hall, R. J.

R. J. Hall, Opt. Eng. 22, 322 (1983).
[CrossRef]

Johnston, S. C.

L. A. Rahn, S. C. Johnston, R. L. Farrow, P. L. Mattern, Temperature, Vol. 5 (American Institute of Physics, New York, 1982), Part 1, p. 609.

Klick, D.

D. Klick, K. A. Marko, L. Rimai, Appl. Opt. 20, 1178 (1981).
[CrossRef] [PubMed]

D. Klick, K. A. Marko, L. Rimai, Temperature, Vol. 5 (American Institute of Physics, New York, 1982), Part 1, p. 615.

Liesegang, G.

Long, M. B.

R. K. Chang, M. B. Long, Topics in Applied Physics, Vol. 50 (Springer, Berlin, 1982), Chap. 3, p. 179.
[CrossRef]

Maker, P. D.

P. D. Maker, R. W. Terhune, Phys. Rev. A 137, 801 (1965).

Marko, K. A.

Mattern, P. L.

L. A. Rahn, S. C. Johnston, R. L. Farrow, P. L. Mattern, Temperature, Vol. 5 (American Institute of Physics, New York, 1982), Part 1, p. 609.

L. A. Rahn, R. L. Farrow, P. L. Mattern, presented at the 8th International Conference on Raman Spectroscopy, Bordeaux, France, Sept. 1982.

Meyer, H.

Mitzkus, R.

Moya, F.

M. Pealat, J.-P. E. Taran, F. Moya, Opt. Laser Technol. 12, 21 (1980).
[CrossRef]

Pealat, M.

M. Pealat, J.-P. E. Taran, F. Moya, Opt. Laser Technol. 12, 21 (1980).
[CrossRef]

Rahn, L. A.

L. A. Rahn, R. L. Farrow, P. L. Mattern, presented at the 8th International Conference on Raman Spectroscopy, Bordeaux, France, Sept. 1982.

L. A. Rahn, S. C. Johnston, R. L. Farrow, P. L. Mattern, Temperature, Vol. 5 (American Institute of Physics, New York, 1982), Part 1, p. 609.

Regnier, P. R.

P. R. Regnier, J.-P. E. Taran, Appl. Phys. Lett. 23, 240 (1973).
[CrossRef]

Rimai, L.

Roh, W. B.

W. B. Roh, P. W. Schreiber, J.-P. E. Taran, Appl. Phys. Lett. 29, 174 (1976).
[CrossRef]

Schreiber, P. W.

W. B. Roh, P. W. Schreiber, J.-P. E. Taran, Appl. Phys. Lett. 29, 174 (1976).
[CrossRef]

Smith, P. D.

Staerk, H.

Stenhouse, I. A.

Stufflebeam, J. H.

A. C. Eckbreth, G. M. Dobbs, J. H. Stufflebeam, P. A. Tellex, AIAA Paper No. 83-1294 (1983).

Switzer, G. L.

G. L. Switzer, L. P. Goss, Temperature, Vol. 5 (American Institute of Physics, New York, 1982), Part 1, p. 583.

Swords, M. D.

Taran, J.-P. E.

For example, S. A. J. Druet, J.-P. E. Taran, Prog. Quantum Electron. 7, 1 (1981).
[CrossRef]

M. Pealat, J.-P. E. Taran, F. Moya, Opt. Laser Technol. 12, 21 (1980).
[CrossRef]

W. B. Roh, P. W. Schreiber, J.-P. E. Taran, Appl. Phys. Lett. 29, 174 (1976).
[CrossRef]

P. R. Regnier, J.-P. E. Taran, Appl. Phys. Lett. 23, 240 (1973).
[CrossRef]

Tellex, P. A.

A. C. Eckbreth, G. M. Dobbs, J. H. Stufflebeam, P. A. Tellex, AIAA Paper No. 83-1294 (1983).

Terhune, R. W.

P. D. Maker, R. W. Terhune, Phys. Rev. A 137, 801 (1965).

Williams, D. R.

Appl. Opt. (6)

Appl. Phys. Lett. (2)

P. R. Regnier, J.-P. E. Taran, Appl. Phys. Lett. 23, 240 (1973).
[CrossRef]

W. B. Roh, P. W. Schreiber, J.-P. E. Taran, Appl. Phys. Lett. 29, 174 (1976).
[CrossRef]

Combust. Flame (1)

A. C. Eckbreth, Combust. Flame 39, 133 (1980).
[CrossRef]

Opt. Eng. (1)

R. J. Hall, Opt. Eng. 22, 322 (1983).
[CrossRef]

Opt. Laser Technol. (1)

M. Pealat, J.-P. E. Taran, F. Moya, Opt. Laser Technol. 12, 21 (1980).
[CrossRef]

Opt. Lett. (2)

Phys. Rev. A (1)

P. D. Maker, R. W. Terhune, Phys. Rev. A 137, 801 (1965).

Prog. Quantum Electron. (1)

For example, S. A. J. Druet, J.-P. E. Taran, Prog. Quantum Electron. 7, 1 (1981).
[CrossRef]

Other (11)

Cyclic variation in pressure is seen in all IC engines, including ours. Cyclic variation in temperature was reported by us in Ref. 10. Time of flame arrival was measured by the deflection of an expanded He–Ne beam focused in the chamber center. Variations of ±3 CA° in this time were seen and were correlated with cyclic variations in peak pressure. All these variations were greatly reduced in the study of Ref. 6 by inducing an unrealistically large swirl.

Viewing the pump beam spectrum with the high-resolution spectrometer, we see three peaks (modes) with the etalon detuned. Tuning the etalon suppresses the sidebands far below the central peak, giving essentially single-mode operation. The etalon is tuned before each run and remains tuned for the duration of a run.

A set of simultaneous engine and reference spectra were acquired with the engine filled with Ideally, the divided spectrum CO2. for each pulse would be flat, but the normalization is not perfect and noise remains. Integrating spectral passbands of these normalized spectra as we would for a temperature determination, we found an effect on temperature due to the imperfect normalization of ±80 K at 2000 K. Thus, imperfect normalization accounts in large part for the imprecision of CARS temperature readings in a stable burner reported earlier by us.10An alternative normalization procedure has been employed11 which assumes that the overall dye laser shape is repeatable. To test this procedure, we normalized the set of engine spectra described above with the average reference spectrum and found only a 20% rise in the temperature imprecision that would be due to imperfect normalization and dye laser noise. However, for some pulses there were regions of the engine spectrum that poorly matched the average reference spectrum. If individual reference spectra are not used for normalization, the most stable region of the dye laser spectral profile should be centered over the region of interest, and a method for deleting spectra generated by distorted dye profiles should be employed.11

R. K. Chang, M. B. Long, Topics in Applied Physics, Vol. 50 (Springer, Berlin, 1982), Chap. 3, p. 179.
[CrossRef]

For most of the engine cycle, almost every pulse yields a usable spectrum. Only from 0–6 CA° are the majority of spectra deflected, coinciding with the fluctuating time of flame arrival.14 It is clear that the temperature histograms acquired during this short period might be biased (e.g., more hot spectra than cold spectra might be deflected), and that the histograms may have more to do with cyclic variation in flame arrival than with flame structure.

L. A. Rahn, R. L. Farrow, P. L. Mattern, presented at the 8th International Conference on Raman Spectroscopy, Bordeaux, France, Sept. 1982.

L. A. Rahn, S. C. Johnston, R. L. Farrow, P. L. Mattern, Temperature, Vol. 5 (American Institute of Physics, New York, 1982), Part 1, p. 609.

The equivalent analog operation could be performed with the signal from a standard camera turned at 90° so that the electron beam scans along spectral lines.

G. L. Switzer, L. P. Goss, Temperature, Vol. 5 (American Institute of Physics, New York, 1982), Part 1, p. 583.

D. Klick, K. A. Marko, L. Rimai, Temperature, Vol. 5 (American Institute of Physics, New York, 1982), Part 1, p. 615.

A. C. Eckbreth, G. M. Dobbs, J. H. Stufflebeam, P. A. Tellex, AIAA Paper No. 83-1294 (1983).

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Figures (7)

Fig. 1
Fig. 1

Single-pulse N2Q-band spectra acquired at various times in the engine cycle. Time is given in degrees of engine rotation from the top of the power stroke.

Fig. 2
Fig. 2

Block diagram of the engine CARS apparatus with video detection system.

Fig. 3
Fig. 3

Noncollinear phase-matching scheme for CARS measurements in turbulent flames.

Fig. 4
Fig. 4

Cross section of the Waukesha CFR engine at the top of the 83-mm diam combustion chamber.

Fig. 5
Fig. 5

Single-frame image of a postflame spectrum from the engine (30 CA°) and the corresponding reference spectrum. Image from videotape was digitized with one-bit resolution.

Fig. 6
Fig. 6

O, Q, and S bands of STP N2 in an unnormalized single-pulse spectrum acquired from videotape (input beams cross-polarized).

Fig. 7
Fig. 7

Comparison of single-pulse postflame (20 CA°) N2Q-band normalized spectra acquired by two methods: using the PAR OMA 2 (middle) and using the video OMA (bottom). At top is a model calculation at the temperature (2200 K) and pressure (42 atm) determined from these data. The calculation is the same as that described in Ref. 10 with three additions: An empirical equation fitting Rahn’s data21 has been added to account for the dependence of line-width on pressure and temperature. A spin-diffusion type model to account for collisional narrowing at a low J value (similar to the model of Hall22) was found to be necessary at this high pressure. And a density-dependent nonresonant background with constant coefficient (determined by best fit to data at many crank angles) is included.

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