EGR stands for exhaust gas recirculation, and the EGR valve is part of a system that recirculates exhaust gas back into the engine’s intake manifold for a return trip to the cylinders it just left.

The engine in the video shows the usage of an SCR or a Selective Catalytic Converter, a Diesel Particulate Filter (PDF), AdBlue urea solution and Exhaust gas recirculation (EGR) system.