Method for evaluating the state of a fuel/air mixture

The invention relates to a method for evaluating the state of a fuel/air mixture and/or the combustion in a combustion chamber of an internal combustion engine, with sample signals of flame light signals, preferably the flame intensity (FI), with associated mixture states being saved to a database, with flame light signals, preferably the flame light intensity (FI), of the combustion in the combustion chamber being detected and thus being compared with the saved sample signals, and with conclusions being drawn on the state of the mixture in the combustion chamber in the case of coincidence between measured and saved signal patterns. In order to enable a simple and precise monitoring of the mixture state and the combustion it is provided that a pressure measurement is also performed in the cylinder simultaneously with the detection of the flame light signals.