Patent ID: 7514264

Claim:
Method for estimating sulfur content in fuel of an internal combustion engine ( 1 ) equipped with at least one cylinder ( 2 ) and at least one catalyser ( 11 ), said catalyser ( 11 ) being capable of storing a quantity of sulfur and NO x groups and being subjected to a regeneration process to remove sulfur, the method providing use of a current sulfur concentration value (S old ) and a correction of said current sulfur concentration value (S old ) in order to obtain a new sulfur concentration value (S new ), comprising the steps of: measuring a first time interval (t 1 -t 0 ) which is actually necessary in order to complete a regeneration process to remove sulfur; determining a quantity (SO xstored ) of sulfur stored in the catalyser ( 11 ) before said regeneration process to remove sulfur, using said current sulfur concentration value (S old ); estimating a second time interval (t 2 -t 0 ) which is theoretically necessary to complete the regeneration process, on the basis of the estimated quantity (SO xstored ) of sulfur stored in the catalyser ( 11 ); determining a multiplicative correction coefficient as a ratio between said first time interval (t 1 -t 0 ) and said second time interval (t 2 -t 0 ); and determining an end of said first time interval (t 1 -t 0 ) which is necessary to complete the regeneration process to remove sulfur according to a time (t 1 ) at which lambda probe ( 14 ) arranged downstream from catalyser ( 11 ) detects a change from lean to rich in gases emitted by the catalyser ( 11 ).