Patent ID: 7283923

Claim:
Method of speed measure on a turbo supercharger of an internal combustion engine by means of vibrations analysis, comprising the steps of: measuring vibrations in said turbo supercharger, said measuring step comprising (a) incorporating software for data processing to integrate measuring equipment to a ROM memory of a computer; (b) connecting a vibration sensor to the measuring equipment and displaying the vibration sensor on a frame of a turbo-compressor; (c) entering into the measuring equipment, the number of blades of a turbo supercharger turbine and then, a number of blades of the turbo supercharger compressor; (d) initiating measuring and digitalizing of N samples of an entrance signal and storing the samples in a RAN memory; (e) obtaining frequency spectrum components of a vibration signal measured by means of FFT; (f) obtaining a PE function which together with the FFT function allows determination of a harmonic correlation function applying the following expression: CA ⁡ ( x ) = The ⁢ ⁢ biggest ⁢ ⁢ of ⁢ ⁢ 〈 CA ⁡ ( x ) k 〉 = ∏ i = 1 n ⁢ E ⁡ ( i · x + k · i / n ) · PE ⁡ ( i ) ( 9 ) Where: k=is a value between 1 and n, CA(x)=Harmonic Correlation Function, E(x)=Spectrum Function, calculated with a TRF of the sensed signal, PE=Spectral Comb Function, n=Number of harmonic to consider, x=Frequency of a value between 0 and a maximum frequency obtained in the FFT; and (g) obtaining RPM starting from a frequency corresponding to a maximum value of the CA function.