Modeling of NOx Emissions of Biodiesel Fuels

Wenqiao Yuan, Alan C. Hansen, Zhongchao Tan

Research output: Contribution to conferencePaperpeer-review


Biodiesel is a promising alternative to petroleum-based diesel fuel because it is renewable and its extensive use in unmodified engines has proved to be very successful. However, its future use may be limited by the higher oxides of nitrogen (NOx) emissions that are typically generated relative to petroleum diesel. The purpose of this research was to increase the scientific understanding of the fundamental mechanisms of NOx generation in diesel engines fueled with biodiesel through modeling of the spray, ignition and combustion process of biodiesel, and to evaluate some strategies for reducing NOx emissions. Computational methods were developed to estimate the physical and thermodynamic properties of biodiesel for combustion modeling. The computed fuel properties were input into KIVA-3V program for modeling of the spray, ignition, combustion, and NOx emissions of biodiesel in diesel engines. Several sub-models were developed for KIVA-3V to include biodiesel in the fuel library. The predicted cylinder pressure, heat release and NO x emissions from the modified KIVA-3V model were compared to and were found to be in close agreement with experimental data that were collected from a John Deere 4045T diesel engine fueled with diesel (D2), soybean methyl ester (SME), yellow grease methyl ester (YGME), and genetically modified soybean methyl ester (GMSME). Higher overall cylinder temperatures were observed for SME compared to D2, which was regarded as a direct cause of the higher NO x emissions of SME. Based on the computational modeling results, the higher overall cylinder temperatures of SME were attributed to the earlier start of injection and decreased spray cone angle, which were seen as the leading reasons for higher NOx emissions. Computational modeling was applied to evaluate strategies for reducing NOx emissions from biodiesel combustion. The results indicated that increasing spray cone angle, retarding start of injection, applying exhaust gas recirculation (EGR) and charge air cooling were all effective in reducing NOx emissions from biodiesel.

Original languageEnglish (US)
StatePublished - 2005
Event2005 ASAE Annual International Meeting - Tampa, FL, United States
Duration: Jul 17 2005Jul 20 2005


Other2005 ASAE Annual International Meeting
Country/TerritoryUnited States
CityTampa, FL


  • Biodiesel
  • Combustion
  • Egr; ignition
  • Modeling
  • No
  • Spray

ASJC Scopus subject areas

  • Agricultural and Biological Sciences(all)
  • Bioengineering


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