ɸ-Sensitivity Evaluation of n-Butanol and Iso-Butanol Blends with Surrogate Gasoline

Using renewable fuels is a reliable approach for decarbonization of combustion engines. iso-Butanol and n-butanol are known as longer chain alcohols and have the potential of being used as gasoline substitute or a renewable fraction of gasoline. The combustion behavior of renewable fuels in modern combustion engines and advanced combustion concepts is not well understood yet. Low-temperature combustion (LTC) is a concept that is a basis for some of the low emissions-high efficiency combustion technologies. Fuel ɸ-sensitivity is known as a key factor to be considered for tailoring fuels for these engines. The Lund ɸ-sensitivity method is an empirical test method for evaluation of the ɸ-sensitivity of liquid fuels and evaluate fuel behavior in thermal. iso-Butanol and n-butanol are two alcohols which like other alcohol exhibit nonlinear behavior when blended with (surrogate) gasoline in terms of RON and MON. In this study, first the Lund ɸ-sensitivity numbers of iso-butanol and n-butanol at CA50≈3°CA after TDC is measured. CA50 is the rank angle degree at which 50% of total accumulated heat is released. Then, the Lund ɸ-sensitivity number of iso-butanol at two later combustion phasing of CA50≈8 & 6 °CA after TDC is evaluated. Finally, the Lund ɸ-sensitivity number of volumetric blends of iso-butanol and surrogate gasoline (RON≈87) were measured. The results show the ɸ-sensitivity of iso-butanol is lower than n-butanol which means the combustion behavior of iso-butanol is less sensitive to thermal and fuel stratification. The nonlinear behavior of Lund ɸ-sensitivity number of iso-butanol blends with surrogate gasoline is observed. As expected, the later combustion phasing lowers the Lund ɸ-sensitivity number of the tested fuel and increases the experimental range successfully.