Patent ID: 6347519
Filing Date: 2002-02-19
Classification: F02B,F02D,G01F,Y02T

Abstract:
A system for measuring the mass flow rate of recirculated exhaust gas in a vehicle having a compression-ignition engine, a plurality of engine sensors having outputs indicative of current engine conditions including an intake manifold pressure sensor, and a variable geometry turbocharger in which geometry is varied by a controllable actuator, the system comprising:an exhaust gas recirculation valve mounted in the engine exhaust line for controllably diverting a selected portion of the exhaust gas for mixture with intake air; a temperature sensor mounted in the flow path of the recirculated exhaust gas; an obstruction in the flow path of the recirculated exhaust gas; a differential pressure sensor including a first pressure tap located for sensing the pressure of the recirculated exhaust gas upstream of the obstruction, and a second pressure tap located for sensing the pressure of the recirculated exhaust gas downstream of the obstruction; and control logic for determining flow rate of the recirculated exhaust gas as a function of the current intake manifold pressure, recirculated exhaust gas temperature, and differential pressure drop across the obstruction.