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Real-Time Calibration of Planar Laser Induced Fluorescence Air/Fuel-Ration Measurements in Combustion Environments Using in-situ Raman Scattering

Richter, Mattias LU ; Axelsson, Boman LU ; Nyholm, Kay and Aldén, Marcus LU (1998) In Symposium (International) on Combustion 27(1). p.51-57
Abstract
A laser-based technique for recording absolute air-fuel ratio maps in a single-laser pulse in combustion devices, for instance, prior to ignition in internal combustion engines, is demonstrated. The method is based on an in situ pulse-to-pulse calibration of two-dimensional laser-induced fluorescence (LIF) images of relative fuel distributions by a point Raman measurement. A single excimer laser pulse is used to quasisimultaneously detect planar LIF from a fuel tracer as well as spectrally resolved Raman scattering from oxygen and fuel in one point inside the LIF image plane. By determining the air-fuel ratio in this particular point from the measured Raman signals, the whole LIF image can be scaled, and quantitative two-dimensional... (More)
A laser-based technique for recording absolute air-fuel ratio maps in a single-laser pulse in combustion devices, for instance, prior to ignition in internal combustion engines, is demonstrated. The method is based on an in situ pulse-to-pulse calibration of two-dimensional laser-induced fluorescence (LIF) images of relative fuel distributions by a point Raman measurement. A single excimer laser pulse is used to quasisimultaneously detect planar LIF from a fuel tracer as well as spectrally resolved Raman scattering from oxygen and fuel in one point inside the LIF image plane. By determining the air-fuel ratio in this particular point from the measured Raman signals, the whole LIF image can be scaled, and quantitative two-dimensional air-fuel ratio data can be obtained. In the method, it is crucial to achieve a Raman signal that can be spectrally separated from the much stronger LIF signal. Therefore, the behavior of the Raman signals from air and fuels, like iso-octane and methane, was studied in a cell as well as in a four-stroke spark ignition engine. Especially, spectral interferences from commonly used fluorescent additives (3-pentanone and acetone) with the Raman signals were investigated. Moreover, possibilities for suppressing the background originating from fluorescent tracers by taking advantage of the polarization characteristics of Raman scattering is briefly addressed. Finally, demonstration measurements of the calibration technique are presented, and the precision and accuracy of the method are shortly discussed. (Less)
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publishing date
type
Contribution to journal
publication status
published
subject
in
Symposium (International) on Combustion
volume
27
issue
1
pages
51 - 57
publisher
Elsevier
external identifiers
  • scopus:0032265456
ISSN
1540-7489
DOI
10.1016/S0082-0784(98)80389-5
language
English
LU publication?
yes
id
5443c218-8c40-4383-85fa-46658b607b30
date added to LUP
2019-05-16 15:35:21
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@article{5443c218-8c40-4383-85fa-46658b607b30,
  abstract     = {A laser-based technique for recording absolute air-fuel ratio maps in a single-laser pulse in combustion devices, for instance, prior to ignition in internal combustion engines, is demonstrated. The method is based on an in situ pulse-to-pulse calibration of two-dimensional laser-induced fluorescence (LIF) images of relative fuel distributions by a point Raman measurement. A single excimer laser pulse is used to quasisimultaneously detect planar LIF from a fuel tracer as well as spectrally resolved Raman scattering from oxygen and fuel in one point inside the LIF image plane. By determining the air-fuel ratio in this particular point from the measured Raman signals, the whole LIF image can be scaled, and quantitative two-dimensional air-fuel ratio data can be obtained. In the method, it is crucial to achieve a Raman signal that can be spectrally separated from the much stronger LIF signal. Therefore, the behavior of the Raman signals from air and fuels, like iso-octane and methane, was studied in a cell as well as in a four-stroke spark ignition engine. Especially, spectral interferences from commonly used fluorescent additives (3-pentanone and acetone) with the Raman signals were investigated. Moreover, possibilities for suppressing the background originating from fluorescent tracers by taking advantage of the polarization characteristics of Raman scattering is briefly addressed. Finally, demonstration measurements of the calibration technique are presented, and the precision and accuracy of the method are shortly discussed.},
  author       = {Richter, Mattias and Axelsson, Boman and Nyholm, Kay and Aldén, Marcus},
  issn         = {1540-7489},
  language     = {eng},
  number       = {1},
  pages        = {51--57},
  publisher    = {Elsevier},
  series       = {Symposium (International) on Combustion},
  title        = {Real-Time Calibration of Planar Laser Induced Fluorescence Air/Fuel-Ration Measurements in Combustion Environments Using in-situ Raman Scattering},
  url          = {http://dx.doi.org/10.1016/S0082-0784(98)80389-5},
  doi          = {10.1016/S0082-0784(98)80389-5},
  volume       = {27},
  year         = {1998},
}