Patent ID: 7665448

Claim:
A method of determining the exhaust pressure (P r ) of a turbocharged internal combustion engine comprising a wastegate, characterized in that an exhaust pressure (P i ) is determined, as a function of the engine intake air flow rate (A r ), of the engine speed (R r ) and of the degree of wastegate opening (T r ), by an interpolation from a reference map comprising exhaust pressure values (P c ) for defined values of the intake air flow rate (A c ), of the engine speed (R c ) and of the degree of wastegate opening (T c ), the exhaust pressure determined by the interpolation (P i ) is corrected, as a function of the ambient pressure prevailing during the determination of the exhaust pressure (P a ) and of the ambient pressure prevailing during the production of the map (P o ), according to the formula which follows: P r = P i ( P i ( 1 - P a P o K - P a ) + K ⁢ ⁢ P a P o - P a K - P a ) in which P r is the corrected exhaust pressure, P i is the exhaust pressure determined by the interpolation, P o is the ambient pressure prevailing during the production of the map, P a is the ambient pressure prevailing during the determination of the exhaust pressure, and K is a corrective factor which is specific to the type of engine for which the map was produced and which is predetermined on a test bench by calibrating measurements at different ambient pressures.