Marcel Eberbach provides insight into the investigations of the knocking behavior of methane-based fuels and compares them with the knocking behavior of very high knock resistant liquid fuels during engine combustion. With pressure-based knock detection algorithms and thermodynamic evaluation, the atypical knocking combustion phenomena are evaluated with respect to the abnormalities on the heat release curve. Based on the investigated fuels an engine specific relation between the fuel index numbers (RON and MN) and the actual knock resistance of the fuels by means of the motor methane number was established and applied to the investigated gaseous and liquid fuels during knocking combustion.