High flow (delta p) differential pressure egr system with provision for both flow control and obd monitor

The invention relates to a high flow (delta P) differential pressure EGR System with provision for both flow control and OBD monitor. In one approach, a method for measuring exhaust gas recirculation flow in an engine is provided. The method comprises separating EGR flow into at least a first flow and a second flow, passing the separated first flow through a restriction region, where the first flow passes through the restriction region separately from the separated second flow, combining the separated second flow and inducting the combined flows into a cylinder of the engine, wherein the EGR flow is separated and then combined within a common EGR passage. The system and method in the invention can exactly control the higher and lower EGR flow through EGR valve and reduce the overall assemble design of the EGR system.