Wavelet analysis of in-cylinder ldv measurements and correlation against heat-release

Fredrik Söderberg*, Bengt Johansson, Bengt Lindoff

*Corresponding author for this work

Research output: Contribution to conferencePaperpeer-review

5 Scopus citations

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 heat release. Correlation against heat-release 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.

Original languageEnglish (US)
DOIs
StatePublished - Dec 1 1998
Event1998 SAE International Congress and Exposition - Detroit, MI, United States
Duration: Feb 23 1998Feb 26 1998

Other

Other1998 SAE International Congress and Exposition
CountryUnited States
CityDetroit, MI
Period02/23/9802/26/98

ASJC Scopus subject areas

  • Automotive Engineering
  • Safety, Risk, Reliability and Quality
  • Pollution
  • Industrial and Manufacturing Engineering

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