Technical Paper
Cooled EGR Rate Measurement with a Thermal Anemometer for EPA02 Heavy Duty Diesel Engine Emission Control
2003-03-03
2003-01-0263
Cooled EGR is one of the engine technologies that has been certified by the EPA for on-highway heavy duty diesel engines to meet the EPA October 2002 2.5 g/bhp-hr NMHC + NOx and 0.1 g/bhp-hr particulate matter exhaust emission regulation. Cooled EGR as the primary exhaust emission control reduction technology also minimizes the fuel economy penalty associated with this exhaust emission regulation. The cooled EGR system however requires precise EGR rate of flow control in a very unfriendly environment that includes acidic exhaust gas condensates, static pressures up to 4 Bar, temperatures over the entire range of -40 to 250° C, and high engine vibration levels. Several technologies have been proposed and evaluated to achieve a closed loop feedback signal for the EGR flow control valve and VGT (Variable Geometry Turbocharger) vane position.
