An essential task in the optimization of combustion processes for DISI (Direct Injection Spark Ignition) engines is the generation of a suitable in-cylinder flow, leading to easy ignition conditions and low pollutant emissions. Therefore, the determination of the transient flow behaviour generated in the cylinder by the intake port and the identification of the origin of flow fluctuations are equally important. A better insight into the time-dependent behaviour of in-cylinder flow is necessary to avoid unwanted flow variations and enhance the fuel-mixture preparation. Suitable information is provided here by the experimental measurement of instantaneous flow fields in a model cylinder flow, as obtained from High Speed Particle Image Velocimetry. The investigated flow fields are generated by a four-valve DISI production engine cylinder head on a steady-state test-bed. The present paper presents a procedure based on Singular Value Decomposition (SVD) in order to filter out measurement errors and to obtain information about the transient behaviour of in-cylinder flows. First, the procedure is presented and analyzed by considering generic vector fields, demonstrating that information concerning the transient behaviour is detectable in this manner. Next, the transient behaviour of the in-cylinder flow is investigated by reconstructing flow fields with the SVD procedure. The reconstruction employs a specified number of SVD spatial modes φ i (x) and corresponding SVD time coefficients a Di (t), which are reduced to their deterministic parts. Afterwards, the reduced SVD time coefficients a Di (t) are used to determine the main fluctuation frequencies of the in-cylinder flow and to identify the origin of these fluctuations.
Experiments in Fluids – Springer Journals
Published: Sep 16, 2009
It’s your single place to instantly
discover and read the research
that matters to you.
Enjoy affordable access to
over 18 million articles from more than
15,000 peer-reviewed journals.
All for just $49/month
Query the DeepDyve database, plus search all of PubMed and Google Scholar seamlessly
Save any article or search result from DeepDyve, PubMed, and Google Scholar... all in one place.
Get unlimited, online access to over 18 million full-text articles from more than 15,000 scientific journals.
Read from thousands of the leading scholarly journals from SpringerNature, Elsevier, Wiley-Blackwell, Oxford University Press and more.
All the latest content is available, no embargo periods.
“Hi guys, I cannot tell you how much I love this resource. Incredible. I really believe you've hit the nail on the head with this site in regards to solving the research-purchase issue.”Daniel C.
“Whoa! It’s like Spotify but for academic articles.”@Phil_Robichaud
“I must say, @deepdyve is a fabulous solution to the independent researcher's problem of #access to #information.”@deepthiw
“My last article couldn't be possible without the platform @deepdyve that makes journal papers cheaper.”@JoseServera