Physical and chemical characterization of SIDI engine particulates

Chethan K. Gaddam, Randy L. Vander Wal

Research output: Contribution to journalArticlepeer-review

135 Scopus citations


Carbonaceous soot particles from a spark-ignition direct-injection (SIDI) engine are characterized by physical and chemical techniques. Physical characterization included aggregate size and morphology, primary particle size and internal nanostructure, each by transmission electron microscopy (TEM) and corresponding image analyses. Chemical characterization included composition and bonding as analyzed by X-ray photoelectron spectroscopy (XPS) and Fourier Transform Infrared - Attenuated Total Reflectance spectroscopy (FTIR-ATR). Engine operational conditions included lean, rich, high-load cases and an advanced ignition test, each relative to a reference condition. The aggregates formed for the operational modes with less time for in-cylinder mixing appeared to be more compact with the primary soot particles exhibiting a higher level of tortuous nanostructure. XPS analysis indicated considerable organic matter content while FTIR-ATR confirmed that the organic component was not condensed volatiles but instead matrix bound organics. A small (<15%) surface oxygen content was observed by XPS, consistent with FTIR results suggesting that the organic content is largely alkyl hydrocarbons rather than oxygenated species.

Original languageEnglish (US)
Pages (from-to)2517-2528
Number of pages12
JournalCombustion and Flame
Issue number11
StatePublished - Nov 2013

All Science Journal Classification (ASJC) codes

  • General Chemistry
  • General Chemical Engineering
  • Fuel Technology
  • Energy Engineering and Power Technology
  • General Physics and Astronomy


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