Advanced

A study of the influence of exhaust gas recirculation and stoichiometry on the heat release in the end-gas prior to knock using rotational coherent anti-Stokes-Raman spectroscopy thermometry

Grandin, Börje; Denbratt, Ingemar; Bood, Joakim LU ; Brackmann, Christian LU and Bengtsson, Per-Erik LU (2002) In International Journal of Engine Research 3(4). p.209-221
Abstract
Heat release in the end-gas prior to autoignition was investigated using different experimental methods including transducers for heat flux and pressure as well as rotational coherent anti-Stokes-Raman spectroscopy, which is a laser-based method for non-intrusive instantaneous thermometry of the gas. The time history was examined in the cases of mixtures of various stoichio-metries, where some were diluted with exhaust gas recir-culation (EGR). The measured temperature history was compared with the isentropic temperature calculated from the cylinder pressure trace. This comparison revealed a difference in heat release from low-temperature reactions in the end-gas for the various mixtures tested at a constant indicated mean effective... (More)
Heat release in the end-gas prior to autoignition was investigated using different experimental methods including transducers for heat flux and pressure as well as rotational coherent anti-Stokes-Raman spectroscopy, which is a laser-based method for non-intrusive instantaneous thermometry of the gas. The time history was examined in the cases of mixtures of various stoichio-metries, where some were diluted with exhaust gas recir-culation (EGR). The measured temperature history was compared with the isentropic temperature calculated from the cylinder pressure trace. This comparison revealed a difference in heat release from low-temperature reactions in the end-gas for the various mixtures tested at a constant indicated mean effective pressure and a fixed position of 50 per cent burnt charge. It is shown that lean mixtures tend to exhibit the highest knock intensity, mainly due to a decrease in specific heat, as compared to the richer mixtures, which result in an earlier knock onset and as a consequence higher knock intensity. Furthermore, the comparison of temperatures indicates that the rich mixtures have a high heat release from low-temperature chemistry, which to some extent negates the higher specific heat of the charge. As a consequence, a slight enrichment of the charge can lead to higher knock intensity in comparison with a stoichiometric mixture. In spite of the lower specific heat of the charge when a stoichiometric charge was diluted with cooled EGR, these mixtures showed a very low tendency to knock. (Less)
Please use this url to cite or link to this publication:
author
organization
publishing date
type
Contribution to journal
publication status
published
subject
keywords
laser diagnostics combustion Coherent anti-stokes raman spectroscopy CARS Heat release autoignition knock
in
International Journal of Engine Research
volume
3
issue
4
pages
209 - 221
publisher
Professional Engineering Publishing
external identifiers
  • scopus:84990317211
ISSN
1468-0874
DOI
10.1243/146808702762230914
language
English
LU publication?
yes
id
195d1592-e6ce-4fe4-bd9a-a445f4661b3f (old id 744630)
date added to LUP
2007-12-12 18:09:34
date last changed
2017-09-24 04:52:53
@article{195d1592-e6ce-4fe4-bd9a-a445f4661b3f,
  abstract     = {Heat release in the end-gas prior to autoignition was investigated using different experimental methods including transducers for heat flux and pressure as well as rotational coherent anti-Stokes-Raman spectroscopy, which is a laser-based method for non-intrusive instantaneous thermometry of the gas. The time history was examined in the cases of mixtures of various stoichio-metries, where some were diluted with exhaust gas recir-culation (EGR). The measured temperature history was compared with the isentropic temperature calculated from the cylinder pressure trace. This comparison revealed a difference in heat release from low-temperature reactions in the end-gas for the various mixtures tested at a constant indicated mean effective pressure and a fixed position of 50 per cent burnt charge. It is shown that lean mixtures tend to exhibit the highest knock intensity, mainly due to a decrease in specific heat, as compared to the richer mixtures, which result in an earlier knock onset and as a consequence higher knock intensity. Furthermore, the comparison of temperatures indicates that the rich mixtures have a high heat release from low-temperature chemistry, which to some extent negates the higher specific heat of the charge. As a consequence, a slight enrichment of the charge can lead to higher knock intensity in comparison with a stoichiometric mixture. In spite of the lower specific heat of the charge when a stoichiometric charge was diluted with cooled EGR, these mixtures showed a very low tendency to knock.},
  author       = {Grandin, Börje and Denbratt, Ingemar and Bood, Joakim and Brackmann, Christian and Bengtsson, Per-Erik},
  issn         = {1468-0874},
  keyword      = {laser diagnostics
combustion
Coherent anti-stokes raman spectroscopy
CARS
Heat release
autoignition
knock},
  language     = {eng},
  number       = {4},
  pages        = {209--221},
  publisher    = {Professional Engineering Publishing},
  series       = {International Journal of Engine Research},
  title        = {A study of the influence of exhaust gas recirculation and stoichiometry on the heat release in the end-gas prior to knock using rotational coherent anti-Stokes-Raman spectroscopy thermometry},
  url          = {http://dx.doi.org/10.1243/146808702762230914},
  volume       = {3},
  year         = {2002},
}