Machado, G., Barros, J., Braga, S., and Braga, C., "Influence of Toluene and Iso-Octane on Combustion and Performance Parameters of Spark Ignition Engines," SAE Technical Paper 2013-36-0229, 2013, doi:10.4271/2013-36-0229.
Commercial gasoline is composed of hundreds of hydrocarbon components. Surrogate fuels that decrease the chemical and physical complexity of gasoline are being used to allow a better understanding of the processes involved in the interaction between fuels and internal combustion engines (ICEs). Based on previous published works about methodologies for fuel development using surrogate fuels, the aim of this paper is to present further results on the effect of individual components and fuel fractions on the combustion and performance parameters of spark ignition engines. SI engine dynamometer tests were conducted using ten mixtures of iso-octane, toluene, n-heptane and ethanol. Response surface models were statistically developed to analyze the interactions between fuel components, fuel properties and engine performance. For the operating conditions susceptible to knocking, favored by engines with higher compression ratios, toluene and iso-octane are important components, mainly due to their higher octane ratings. This paper discusses the potential advantages of using toluene or iso-octane and their corresponding chemical groups for different engine performance parameters. The results and technical information presented can help fuel formulation in general and can be of particular interest for special applications involving higher compression ratio engines.