Patent ID: 8028569

Claim:
A method for providing a specification about an efficiency of a cooler for recirculated exhaust gas in an internal combustion engine, comprising: measuring, at a temperature detector, a temperature of the recirculated exhaust gas cooled by the cooler; obtaining a temperature of exhaust gas leaving the internal combustion engine; obtaining a temperature of cooling water flowing through the cooler; obtaining a modeled temperature of the recirculated exhaust gas from a computer-executed cooler model that calculates and outputs the modeled temperature of the recirculated exhaust gas as a function of an efficiency value of a reference cooler; calculating one of an absolute value of the cooler efficiency and a change in the cooler efficiency relative to an efficiency of the reference cooler, wherein the calculating is performed as a function of (i) the measured temperature of the recirculated exhaust gas, (ii) the temperature of the exhaust gas leaving the engine, and (iii) the cooling water temperature; and adjusting the modeled temperature of the recirculated exhaust gas as a function of the calculated one of the absolute value of the cooler efficiency and the change in the cooler efficiency efficiency.