Patent ID: 7521251

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, 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: estimating a first value (NO xstored1 ) of a total quantity of NO x groups stored in the catalyser ( 11 ) by means of a model of NO x group production by the engine ( 1 ), estimating a second value (NO xstored2 ) of the total quantity of NO x groups stored by the catalyser ( 11 ) by means of a model of storage of the catalyser ( 11 ), and determining an additive correction coefficient (D) as the difference between said first estimated value (NO xstored1 ) and said second estimated value (NO xstored2 ), wherein said model of NO x group production by the engine ( 1 ) provides for obtaining a quantity (NO xstored ) of NO x groups stored by the catalyser ( 11 ) by subtracting from a quantity (NO xtotal ) of NO x groups produced by the engine ( 1 ) a quantity (NO xloss ) of NO x groups not captured by the catalyser ( 11 ).