What an EGR Does
Hi wondered what an EGR does and found this:
"EGR Theory. EGR serves one purpose and one purpose only. That purpose is to reduce Oxides of Nitrogen (NOx). Undernormal combustion, Nitrogen(N2)Oxygen (O2) in the air and Hydrocarbons (HC) in the fuel combind into water(H2O) Carbon dioxide (CO2) and the Nitrogen remains unchanged. Under very hot combustion temperatures, the Nitrogen reacts with the other two byproducts and forms Nitrogen oxide (NO). After being released into the atmosphere, it picks up another Oxygen and becomes Nitrogen dioxide (NO2). In the presence of sunlight,
it combines with other compounds like Hydrocarbons and forms Smog. Since exhaust gas is inert (very stable) it doesnt burn again. So by being introduced into
the combustion chamber, it will lower combustion chamber temps enough so that
the Nitrogen doesnt react with the other compounds and is passed unchanged out
the tailpipe thus not contributing to smog. Now, since exhaust gas doesn�t burn, it
doesnt exactly help with combustion. At higher RPMs, this really isnt noticable,
but at idle, the reintroduction of exhaust gas will cause a very rough idle and can
cause stalling if to much is introduced into the combustion chamber"
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