Detection of fuel type on a spark ignition engine from engine vibration behaviour

An experimental investigation of the vibration behaviour of a spark ignition engine fuelled with gasoline, ethanol and methanol blends is presented in this paper. Three types of fuel were used, namely: unleaded gasoline as a base fuel for comparison and two alcohols, namely methanol and ethanol, blended with gasoline at volume percentages of 10%, 20% and 30%. The engine was tested at 1000, 1300, 1600 and 1900 rpm. The experimental results indicated that the vibration amplitude produced by the gasoline fuel was higher at low frequencies around 1500 Hz. On the contrary, the vibration amplitude generated by the gasoline–methanol blend had a high frequency content around 2400 Hz. The gasoline–ethanol blend gave intermediate results at both frequencies. An algorithm was constructed that reliably identified the type of fuel used irrespective of the engine rotational speed.