Impact of exhaust gas recirculation (EGR) on the oxidative reactivity of diesel engine soot

Khalid Al-Qurashi, André L. Boehman*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

255 Scopus citations


This paper expands the consideration of the factors affecting the nanostructure and oxidative reactivity of diesel soot to include the impact of exhaust gas recirculation (EGR). Past work showed that soot derived from oxygenated fuels such as biodiesel carries some surface oxygen functionality and thereby possesses higher reactivity than soot from conventional diesel fuel. In this work, results show that EGR exerts a strong influence on the physical properties of the soot which leads to enhanced oxidation rate. HRTEM images showed a dramatic difference between the burning modes of the soot generated under 0 and 20% EGR. The soot produced under 0% EGR strictly followed an external burning mode with no evidence of internal burning. In contrast, soot generated under 20% EGR exhibited dual burning modes: slow external burning and rapid internal burning. The results demonstrate clearly that highly reactive soot can be achieved by manipulating the physical properties of the soot via EGR.

Original languageEnglish (US)
Pages (from-to)675-695
Number of pages21
JournalCombustion and Flame
Issue number4
StatePublished - Dec 1 2008


  • Diesel particulate
  • Exhaust gas recirculation
  • Nanostructure
  • Reactivity
  • Soot oxidation

ASJC Scopus subject areas

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


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