[mwebb]

Originally Posted by oil pan 4

EGR can help diesels get better FE by warming them up faster.
Once up to temperature EGR gets cut off.

EGR reduces combustion pressure and
thereby reduces Combustion temperature

so
warm up time will NOT be reduced if EGR is used when cold
EGR could possibly be used to heat the incoming fuel air charge ....
a little bit . possibly to improve fuel atomization a little bit

heating intake air from drawing it across the exhaust manifold would do the same thing , better .

EGR does not get cut off when the system is at normal operating temperature because the primary reason there is EGR
is
to reduce
NOX emissions