Patent ID: 7827857
Filing Date: 2010-11-09
Classification: F02D,G01M

Abstract:
1. An estimation method of the crank angle at which 50% of the fuel mass has been burnt in a cylinder ( 2 ) of an internal combustion engine ( 1 ) with spontaneous ignition of the mixture provided with a drive shaft ( 4 ) coupled to a phonic wheel ( 5 ) presenting a number N of teeth ( 6 ); the method comprises the steps of: reading the passage of each tooth ( determining the angular speed (ω determining, by means of a frequency analysis the angular speeds (ω determining an inverse mechanical model (H(j{acute over (ω)})=T/Ω) of the transmission which represents, in the ({acute over (ω)}) frequency domain, the relation between the Fourier transforms of the angular speed (Ω) and of the torque (T) of the internal combustion engine ( determining at least one torque harmonic (T determining a first algebraic function (Ψ) which puts a combustion index (MFB50) into relation with the phase (Arg(T determining the combustion index (MFB50) by applying the first algebraic function (Ψ) to the n