AbstractThe wide range of fuels supplied nowadays has different composition. In order to optimize the combustion process, engine performance and meeting the EPA emissions standards, information about the properties of gasoline should be gained in real time.This study presents a new sensor platform based on a phononic crystal (PnC) sensor and its application as a measuring system for real time gasoline octane number determination. The method is based on the analysis of the transmission spectrum of a phononic crystal sensor filled with the liquid gasoline blend. We could reveal a strong correlation between octane number of the gasoline and the frequency of maximum transmission. Obtained experimental results show that the phononic crystal sensors can be considered as a prospective, competitive and inexpensive device for octane number determination.