Journal of the American Oil Chemists' Society

, Volume 77, Issue 3, pp 285–289 | Cite as

The speed of sound and isentropic bulk modulus of biodiesel at 21°C from atmospheric pressure to 35 MPa

  • Mustafa E. Tat
  • Jon H. Van GerpenEmail author
  • Seref Soylu
  • Mustafa Canakci
  • Abdul Monyem
  • Samuel Wormley


Biodiesel, an alternative diesel fuel consisting of the alkyl monoesters of fatty acids from vegetable oils and animal fats, can be used in existing diesel engines without modification. However, property changes associated with the differences in chemical structure between biodiesel and petroleumbased diesel fuel may change the engine's injection timing. These injection timing changes can change the exhaust emissions and performance from the optimized settings chosen by the engine manufacturer. This study presents the results of measurements of the speed of sound and the isentropic bulk modulus for methyl and ethyl esters of fatty acids from soybean oil and compares them with No. 1 and No. 2 diesel fuel. Data are presented at 21±1°C and for pressures from atmospheric to 34.74 MPa. The results indicate that the speed of sound and bulk modulus of the monoesters of soybean oil are higher than those for diesel fuel and these can cause changes in the fuel injection timing of diesel engines. Linear equations were used to fit the data as a function of pressure, and the correlation constants are given.

Key Words

Biodiesel bulk modulus compressibility diesel fuel ethyl soyate methyl soyate 


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Copyright information

© AOCS Press 2000

Authors and Affiliations

  • Mustafa E. Tat
    • 2
  • Jon H. Van Gerpen
    • 2
    Email author
  • Seref Soylu
    • 2
  • Mustafa Canakci
    • 2
  • Abdul Monyem
    • 2
  • Samuel Wormley
    • 1
  1. 1.Center for Nondestructive EvaluationIowa State UniversityAmes
  2. 2.Mechanical Engineering Dept.Iowa State UniversityAmes

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