Abstract: An abnormal combustion detection and characterization method for spark-ignition internal-combustion engines using combustion indicators is disclosed. A multidimensional space having each dimension corresponding to one of the indicators is defined and a closed surface is defined in this space to surround points corresponding to normal combustions and to not surround points corresponding to abnormal combustions. For each combustion of an engine cycle, the combustion of the cycle is represented by a point in this multidimensional space, the position of this point with respect to the surface is determined and the abnormal nature of the combustion is deduced therefrom.