Method of microphone signal controlling an internal combustion engine

A method of controlling an internal combustion engine having at least one cylinder defining a variable-volume combustion chamber;

• and a rotating crankshaft powered by a piston sliding inside the cylinder;
• the control method comprising the steps of:
• determining a recording window expressed in engine angle degrees and having a start engine angle and a stop engine angle;
• acquiring and memorizing the intensity of sound pressure waves, generated by the internal combustion engine as a function of an engine angle, by means of at least one sound pressure sensor and within the recording window;
• and
• estimating the value of at least one operating parameter of a part of the internal combustion engine by analysing the intensity of the sound pressure waves in the recording window;
• the control method being characterized by comprising the further steps of:
• determining, at a design stage, a distance between the sound pressure sensor and the part of the internal combustion engine to which the operating parameter for assessment refers;
• calculating a transmission delay, expressed in engine degrees, as a function of a rotation speed of the crankshaft and of the distance between the sound pressure sensor and the part of the internal combustion engine to which the operating parameter for assessment refers;
• and
• calculating the start engine angle and stop engine angle of the recording window as a function of the transmission delay.