Patent ID: 8028568

Claim:
A method for determining the angular speed (ω i ) of a drive shaft ( 4 ) of an internal combustion engine ( 1 ) at each tooth event of a phonic wheel ( 5 ) presenting a number N of teeth ( 6 ); the method comprises the steps of: detecting the angular amplitude (Δα i ) for each tooth 6 ; detecting the time (T i ) of each tooth ( 6 ); and determining the raw angular speed (ω raw,i ) of each tooth ( 6 ) according to the corresponding angular amplitude (Δα i ) and time (T i ); the method is characterized in that it comprises the further steps of: determining for each tooth ( 6 ) a compensation value (δμ i ) which represents the difference between the actual angular amplitude of the tooth ( 6 ) and the theoretic angular amplitude of the tooth ( 6 ); and determining the angular speed (ω i ) of each tooth ( 6 ) by correcting the raw angular speed (ω raw,i ) by means of the corresponding compensation value (δμ i ).