<div class="htmlview paragraph">This paper describes a model for EGR mass flow rate estimation as a function of signal smeasured by existing sensors in an internal combustion electronically controlled engine. An original approach is presented to take into account the heat transfer between the EGR duct and the environment. The preliminary results relative to EGR mass flow rate estimation suggest that the methodology may be extended towards the development of a complete model of the intake manifold including the EGR recirculation system and the purge canister.</div>