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Investigations of the Influence of Mixture Preparation on Cyclic Variations in a SI-Engine, Using Laser Induced Fluorescence

Johansson, Bengt LU ; Neij, Hans; Aldén, Marcus LU and Juhlin, Greger (1995) SAE International Congress and Exposition, 1995
Abstract
To study the effect of different injection timings on the charge inhomogeneity, planar laser-induced fluorescence (PLIF) was applied to an operating engine. Quantitative images of the fuel distribution within the engine were obtained. Since the fuel used, iso-octane, does not fluoresce, a dopant was required. Three pentanone was found to have vapor pressure characteristics similar to those of iso-octane as well as low absorption and suitable spectral properties.



A worst case estimation of the total accuracy from the PLIF images gives a maximum error of 0.03 in equivalence ratio. The results show that an early injection timing gives a higher degree of charge inhomogeneity close to the spark plug. It is also known that... (More)
To study the effect of different injection timings on the charge inhomogeneity, planar laser-induced fluorescence (PLIF) was applied to an operating engine. Quantitative images of the fuel distribution within the engine were obtained. Since the fuel used, iso-octane, does not fluoresce, a dopant was required. Three pentanone was found to have vapor pressure characteristics similar to those of iso-octane as well as low absorption and suitable spectral properties.



A worst case estimation of the total accuracy from the PLIF images gives a maximum error of 0.03 in equivalence ratio. The results show that an early injection timing gives a higher degree of charge inhomogeneity close to the spark plug. It is also known that charge inhomogeneity gives a more unstable engine operation. A correlation was noted between the combustion on a cycle to cycle basis and the average fuel concentration within a circular area close to the spark plug center. The correlation coefficient when a second order polynomial was fitted reached a value of mA0.8 when the engine operated with a high degree of inhomogeneity. The highest correlation coefficient between the duration of 0-0.5% heat released and the average fuel concentration was obtained within a radius of approximately 5-10 mm from the spark plug. When the standard disc-shaped combustion chamber was replaced with a turbulence generating geometry, the inhomogeneity of the charge became very low, independent of injection timing. No cycle to cycle correlations between fuel/air equivalence ratio and combustion were then noted. (Less)
Please use this url to cite or link to this publication:
author
organization
publishing date
type
Chapter in Book/Report/Conference proceeding
publication status
published
subject
keywords
Mixture Preparation, LIF, Laser Induced Fluorescence, Cycle-Cycle Variation
host publication
SAE Technical Paper Series
publisher
Society of Automotive Engineers
conference name
SAE International Congress and Exposition, 1995
conference location
Detroit Michigan, United States
conference dates
1995-02-27 - 1995-03-02
external identifiers
  • scopus:28844439969
ISSN
0148-7191
language
English
LU publication?
yes
id
c5041d80-ccce-4f44-a460-16ce130b75b2 (old id 574944)
date added to LUP
2007-11-05 14:46:36
date last changed
2019-01-06 10:06:35
@inproceedings{c5041d80-ccce-4f44-a460-16ce130b75b2,
  abstract     = {To study the effect of different injection timings on the charge inhomogeneity, planar laser-induced fluorescence (PLIF) was applied to an operating engine. Quantitative images of the fuel distribution within the engine were obtained. Since the fuel used, iso-octane, does not fluoresce, a dopant was required. Three pentanone was found to have vapor pressure characteristics similar to those of iso-octane as well as low absorption and suitable spectral properties.<br/><br>
<br/><br>
A worst case estimation of the total accuracy from the PLIF images gives a maximum error of 0.03 in equivalence ratio. The results show that an early injection timing gives a higher degree of charge inhomogeneity close to the spark plug. It is also known that charge inhomogeneity gives a more unstable engine operation. A correlation was noted between the combustion on a cycle to cycle basis and the average fuel concentration within a circular area close to the spark plug center. The correlation coefficient when a second order polynomial was fitted reached a value of mA0.8 when the engine operated with a high degree of inhomogeneity. The highest correlation coefficient between the duration of 0-0.5% heat released and the average fuel concentration was obtained within a radius of approximately 5-10 mm from the spark plug. When the standard disc-shaped combustion chamber was replaced with a turbulence generating geometry, the inhomogeneity of the charge became very low, independent of injection timing. No cycle to cycle correlations between fuel/air equivalence ratio and combustion were then noted.},
  author       = {Johansson, Bengt and Neij, Hans and Aldén, Marcus and Juhlin, Greger},
  issn         = {0148-7191},
  keyword      = {Mixture Preparation,LIF,Laser Induced Fluorescence,Cycle-Cycle Variation},
  language     = {eng},
  location     = {Detroit Michigan, United States},
  publisher    = {Society of Automotive Engineers},
  title        = {Investigations of the Influence of Mixture Preparation on Cyclic Variations in a SI-Engine, Using Laser Induced Fluorescence},
  year         = {1995},
}