Flow measurement of re-circulated exhaust gas in an internal combustion engine

摘要

A system for determining gas flow in a system for re-circulating exhaust gas from an exhaust manifold 48 to an inlet manifold 44 of an internal combustion engine comprises a variable flow control valve 200, a fixed orifice 205 located downstream of the control valve and a computer 12 and pressure sensor 206 for determining mass flow of gas based on a first pressure downstream of the fixed orifice and a differential pressure across the fixed orifice. Calculation of gas flow can further include pressure and temperature correction factors determined from the downstream and differential pressures. The calculated gas flow can be used to control the variable flow control valve. Engine airflow and barometric pressure can be used to modify the calculated gas flow.