Quote:
Originally Posted by SteveDavis
Although you might initially think that the cooler combution chamber temperatures caused by an EGR system would allow you to run more timing, this is not so. The reason being, that the recirculated exhaust gas does not burn very well.
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Well, this answer surprises me, Steve. It would seem that EGR requires you to light the fire earlier precisely because, as you say, " . . . the recirculated exhaust gas does not burn very well." If I understand you, it seems to contradict what I have read in other places, if I understood them.
Here's a quote from, "Fuel Economy in Road Vehicles Powered by Spark Ignition Engines," J. Hilliard & G. Springer, 1984:
" . . . the addition of EGR will cause an increase in fuel consumption at constant spark advance. This is because EGR tends to slow the burning rate in the cylinder thereby introducing an effective spark retard. If, however, the spark advance is increased as EGR is added in a consistent manner, the NOx will reduce as before, but fuel consumption will remain nearly constant."
What am I not getting here?