Dual Path (Low Pressure Loop and High Pressure Loop) EGR for Improved Air Boosting Efficiency

摘要

A method of providing exhaust gas recirculation (EGR) to an air-boosted internal combustion engine. The engine has both a high pressure EGR loop and a low pressure EGR loop. Each EGR loop has a valve that controls the amount of EGR that is delivered to the engine intake from that loop. During low-speed engine conditions, more EGR is delivered to the engine intake from the low pressure EGR loop than from the high pressure EGR loop. During high-speed engine conditions, more EGR is delivered to the engine intake from the high pressure EGR loop than from the low pressure EGR loop.

主权项

1. A method of providing exhaust gas recirculation (EGR) to an internal combustion engine having a turbocharger, the turbocharger having a turbine and compressor, the method comprising:
providing a high pressure EGR loop that directs exhaust gas from the exhaust from a point on the main exhaust line between the exhaust manifold and the turbine to a point on the air intake line between the compressor and the intake manifold; providing a low pressure EGR loop that directs exhaust gas from the exhaust from a point on the main exhaust line downstream the turbine to a point on the air intake line upstream the compressor; defining a low speed range and high-speed range of revolutions per minute (rpm) of the engine at full load; during low-speed engine conditions, directing more EGR through the low pressure EGR loop than the high pressure EGR loop; and during high-speed engine conditions, directing more EGR through the high pressure EGR loop than the low pressure EGR loop.