Lawrence Livermore National Laboratory



A detailed chemical kinetic mechanism for the simulation of gasoline surrogate mixtures has been assembled from existing LLNL mechanisms for n-heptane, iso-octane [1], toluene and C5-C6 olefins [2] and validated using experimental data from shock tubes, stirred reactor, and rapid compression machines [3]. The detailed kinetic model has been used to estimate a surrogate composition targeting a RD387 gasoline (LLNL surrogate) and the obtained formulation was used in comparisons with gasoline experimental flame speeds available in literature [4]. The same surrogate composition coupled with the detailed mechanism here available was successfully applied to the simulation of an HCCI engine under naturally aspirated and boosted conditions [5]. Modeling results obtained from the detailed mechanism were also compared with LLNL surrogate and RD387 rapid compression machine data across a wide range of temperature pressure and equivalence ratios [6-7]. The mechanism performs well at both low and high temperatures and over a broad pressure range important for internal combustion engines. Two reduced versions of the mechanism are available: a 679 species version reduced at University of Connecticut by Prof. Lu and the skeletal mechanism (323 species) presented in [4]. The 679 species reduced mechanism was obtained using the methods described in [8] targeting iso-octane, n-heptane, toluene, 2-pentene and ethanol as pure components and their mixtures. The 323 species mechanism was obtained by our collaborators from University of California targeting the ignition delay times of the 4 component mixture only [4]. This mechanism has not been tested for pure components

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Detailed mechanism

Reduced mechanism I (679 species)

Reduced mechanism II (323 species)

Reference for Mechanism

Mehl M., W.J. Pitz, C.K. Westbrook, H.J. Curran, "Kinetic modeling of gasoline surrogate components and mixtures under engine conditions", Proceedings of the Combustion Institute 33:193-200 (2011).

Other References

  1. Mehl M., W.J. Pitz, M. Sjöberg and J.E. Dec, "Detailed kinetic modeling of low-temperature heat release for PRF fuels in an HCCI engine", SAE 2009 International Powertrains, Fuels and Lubricants Meeting, SAE Paper No. 2009-01-1806, Florence, Italy, 2009. Available at www.sae.org.
  2. Mehl, M., W.J. Pitz, C.K. Westbrook, K. Yasunaga, C. Conroy, H.J Curran, "Autoignition behavior of unsaturated hydrocarbons in the low and high temperature regions", Proceedings of the Combustion Institute, 33:201-208 (2011)
  3. Mehl M., W.J. Pitz, C.K. Westbrook, H.J. Curran, "Kinetic modeling of gasoline surrogate components and mixtures under engine conditions", Proceedings of the Combustion Institute, 33:193-200 (2011).
  4. Mehl M., J.Y. Chen , W.J. Pitz, S.M. Sarathy, C.K. Westbrook, "An Approach for Formulating Surrogates for Gasoline with Application Toward a Reduced Surrogate Mechanism for CFD Engine Modeling", Energy and Fuels, 25:5215-5223 (2011)
  5. Mehl M., W.J. Pitz, S.M. Sarathy, Y. Yang, J.E. Dec "Detailed Kinetic Modeling of Conventional Gasoline at Highly Boosted Conditions and the Associated Intermediate Temperature Heat Release", SAE 2012 World Congress & Exhibition, SAE Paper No. 2012-01-1109, Detroit, MI, USA, 2012. www.sae.org.
  6. Kukkadapu G., K. Kumar, C.-J. Sung, M. Mehl, W. J. Pitz, "Autoignition of Gasoline and its Surrogates in a Rapid Compression Machine", Proceedings of the Combustion Institute, 34:345-352 (2013).
  7. Kukkadapu G., K. Kumar, C.-J. Sung, M. Mehl, W. J. Pitz, "Experimental and Surrogate Modeling Study of Gasoline Ignition in a Rapid Compression Machine", Combustion and Flame, 159:3066-3078 (2012).
  8. 8. Lu T., Law C.K., "Toward accommodating realistic fuel chemistry in large-scale computations ", Prog. Energy Combust. Sci., 35:192-215 (2009).