What is the purpose/function of an EGR valve?

also known as Exhaust Gas Recirculation...|||Exhaust gases are used to lower the combustion temperature. Exhaust gases are inert, they don't combust therefore less combustion takes place while inert gases are added,also while exhaust is assumable hot, it is still cooler than combustion temperatures. High combustion temperatures create nitrogen oxides emissions. EGR work very well at reducing NOx emmissions. |||The EGR valve helps your car more efficiently and completely burn fuel by recirculating a portion of your exhaust and running it through the combustion process again. This results in a cooler, more complete burn of the fuel which decreases you car's noxious emissions by prohibiting the formation of some harmful gases.|||Like its name,to put some exhaust gas back into the intake to burn it again.|||The EGR valve controls the amount of exhaust gas being sent back to your intake maniford to mix with the fresh fuel and air that is being burned. Too much of the exhaust gas will dilute the fuel which would lead to incomplete detonation and loss of power. In extreme situation it can cause valve damage. EGR's are designed to lower the peak combustion temperature of diesels to reduce particulates and NOx to meet EPA emission requirements.