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Wavelet Analysis of In-Cylinder LDV Measurements and Correlation Against Heat-Release

Söderberg, Fredrik LU and Johansson, Bengt LU (1998) In SAE Technical Paper Series 107.
Abstract
Wavelet analysis was used to calculate turbulence and mean velocity levels for LDV measurements made in a four valve spark ignition engine. Five different camshafts were tested, and they produce significantly different flow behaviour. The standard cam gives tumble and with valve deactivation, swirl is produced. One camshaft with early

inlet valve closing and two camshafts with late inlet valve

closing were also tested. The wavelet toolbox for Matlab

version 5.1 has been used for the wavelet calculations.



The wavelet technique produces both time resolved and frequency resolved velocity information. The results indicate some influence of the turbulence frequency content

on the rate of... (More)
Wavelet analysis was used to calculate turbulence and mean velocity levels for LDV measurements made in a four valve spark ignition engine. Five different camshafts were tested, and they produce significantly different flow behaviour. The standard cam gives tumble and with valve deactivation, swirl is produced. One camshaft with early

inlet valve closing and two camshafts with late inlet valve

closing were also tested. The wavelet toolbox for Matlab

version 5.1 has been used for the wavelet calculations.



The wavelet technique produces both time resolved and frequency resolved velocity information. The results indicate some influence of the turbulence frequency content

on the rate of heat release. Correlation against eatrelease can be seen for different scales of turbulence.

The breakdown of the tumble (low frequency turbulence) into high frequency turbulence can be seen clearly. This

transition is not as clear with a swirling flow, where all frequencies are magnified equally at top dead center. The

choice of wavelet does not have a major impact on the

results. (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
LDV, Wavelet, Engine, Combustion
in
SAE Technical Paper Series
volume
107
publisher
Society of Automotive Engineers
external identifiers
  • scopus:84877479315
ISSN
0148-7191
DOI
10.4271/980483
language
English
LU publication?
yes
id
5385bc3f-3169-448e-8be4-a03a2bb6ce90 (old id 620685)
date added to LUP
2016-03-16 12:05:08
date last changed
2017-03-26 04:08:40
@article{5385bc3f-3169-448e-8be4-a03a2bb6ce90,
  abstract     = {Wavelet analysis was used to calculate turbulence and mean velocity levels for LDV measurements made in a four valve spark ignition engine. Five different camshafts were tested, and they produce significantly different flow behaviour. The standard cam gives tumble and with valve deactivation, swirl is produced. One camshaft with early<br/><br>
inlet valve closing and two camshafts with late inlet valve<br/><br>
closing were also tested. The wavelet toolbox for Matlab<br/><br>
version 5.1 has been used for the wavelet calculations.<br/><br>
<br/><br>
The wavelet technique produces both time resolved and frequency resolved velocity information. The results indicate some influence of the turbulence frequency content<br/><br>
on the rate of heat release. Correlation against eatrelease can be seen for different scales of turbulence.<br/><br>
The breakdown of the tumble (low frequency turbulence) into high frequency turbulence can be seen clearly. This<br/><br>
transition is not as clear with a swirling flow, where all frequencies are magnified equally at top dead center. The<br/><br>
choice of wavelet does not have a major impact on the<br/><br>
results.},
  articleno    = {980483},
  author       = {Söderberg, Fredrik and Johansson, Bengt},
  issn         = {0148-7191},
  keyword      = {LDV,Wavelet,Engine,Combustion},
  language     = {eng},
  publisher    = {Society of Automotive Engineers},
  series       = {SAE Technical Paper Series},
  title        = {Wavelet Analysis of In-Cylinder LDV Measurements and Correlation Against Heat-Release},
  url          = {http://dx.doi.org/10.4271/980483},
  volume       = {107},
  year         = {1998},
}