Patent ID: 8201442

Claim:
A method of estimating an instantaneous flow rate of exhaust gas through an exhaust gas recirculation (EGR) conduit fluidly coupled between an exhaust manifold and an intake manifold of an internal combustion engine, the EGR conduit including an EGR cooler disposed in-line therewith, the method comprising: monitoring an operating position of the engine, and executing the following steps at each of a plurality of fixed increments of the engine position, sampling an EGR cooler outlet temperature corresponding to a temperature of gas exiting a gas outlet of the EGR cooler, sampling a pressure differential across a flow restriction disposed in-line with the exhaust gas conduit between the EGR cooler and the intake manifold, sampling an intake manifold pressure corresponding to fluid pressure within the intake manifold, estimating the instantaneous mass flow rate of exhaust gas through the EGR conduit based on the sampled pressure differential, the EGR cooler outlet temperature and the intake manifold pressure, and storing the estimated instantaneous mass flow rate of exhaust gas in a memory unit.