Method for real-time estimation of engine combustion parameters from vibratory signals

A method of determining combustion parameters of an internal-combustion engine including at least one vibration detector providing continuous acquisition as a function of the crank angle of a vibratory signal delivered by the detector and representative of vibrations of the engine, the vibratory signal including harmonics, and real-time filtering of the vibratory signal with a filter, the method comprising:

• constructing a model of the dynamics of the filter and from the constructed model defining an adaptive non-linear estimator comprising a term related to the dynamics and a correction term;
• estimating, in real time, Fourier decomposition coefficients for the vibratory signal acquired by the estimator;
• determining, in real time, combustion parameters from the coefficients;
• and
• determining energy of k harmonics of the vibratory signal using a sum of k squared Fourier decomposition coefficients;
• and
• using the energy of the k harmonics to determine combustion parameters in real time.