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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 In SAE Technical Paper Series
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
in
SAE Technical Paper Series
publisher
Society of Automotive Engineers
conference name
SAE International Congress and Exposition, 1995
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
2017-09-10 04:30:31
@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},
  booktitle    = {SAE Technical Paper Series},
  issn         = {0148-7191},
  keyword      = {Mixture Preparation,LIF,Laser Induced Fluorescence,Cycle-Cycle Variation},
  language     = {eng},
  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},
}