open vs closed egr valve

[rslifkin]

For a diesel, it's more of a pain than it's worth to run EGR (soot becomes an issue, etc.

For a gas engine, it adds more total gas into the intake stream without requiring more fuel (no extra oxygen) or increasing power output. As a result, it takes less energy to suck air past the partly open throttle plate (due to lower intake vacuum) and reduces pumping losses. Often, the increase in total efficiency from the reduced pumping losses is greater than the loss of combustion efficiency from the lower combustion temps.

 

[RobertISaar]

actual amount of EGR gasses by volume are pretty small... very few gasoline engines i've seen run much beyond the 5-7% range.

 

[TFB1]

Originally Posted By: Kees
With a closed egr more nox will build up inside your engine if i understand corectly from varius website,s.(due to lower inlet temp or something)

But less exhaust gas wil dilute the engine with a closed egr .

Now what is the best option for a healthy engine ? blocked or open for hot dirty exhaust gas that lowers nox inside the engine ?



NOX does not return to the engine, 99.99% goes out the tail pipe and contributes to air pollution...

 

[Kestas]

Originally Posted By: artificialist
EGR is a huge disadvantage on diesel engines because extra soot is extra abrasive to the engine, shortening life.

Soot is not abrasive. It may cause other problems, but it is not abrasive.