Method for controlling the operation of an engine with a single-fuel or multiple-fuel injection mode

The method involves determining reference values of a global energy density and a global octane rating resulting from an association of fuels such as natural gas, alcohols, ethers and petrol, and introducing the fuels in a combustion chamber with a proportion to obtain the reference value. Real values of the energy density and/or the octane rating are evaluated from the introduced fuels. Derivation is compensated by varying the proportion of the fuels for obtaining reference energy density and/or octane rating, in case of derivation between the reference values and the real values.