NOx Emission Control Using Large Volume EGR

摘要

An EGR system is disclosed for reducing NO_x emissions and that may eliminate the need for a SCR system. The disclosed EGR system includes dual valves, including a hot EGR valve disposed in the exhaust manifold and a cold EGR valve disposed upstream of the intake manifold. A VGT turbine with adjustable vanes may also be employed with a low pressure turbine. Intake air may proceed through both a high pressure compressor as well as a low pressure compressor and the high pressure compressor may be substantially bypassed by way of a bypass valve disposed between the low pressure compressor and the air intake. The EGR system may be controlled by adjusting the positions of the valves and VGT turbine vanes.