EGR questions...

[Bradford K Palmer]

Believe it or not EGR can be good for something.  A small amount of EGR 
can actually increase effiency.  The EGR adds a bit of thermal mass 
and helps to reduce peak cylinder temperatures(Thats why it works on 
NOX), but this reduction in peak temps. reduces heat transfer to the 
cylinder walls and increases thermal effiency.

On Thu, 25 May 1995, Jonathan R. Lusky wrote:

> Steve=Ravet%Prj=Eng%PCPD=Hou at bangate.compaq.com writes:
> > 
> > I was thinking about this last night...
> > 
> > What would be the effect of lots of EGR under part throttle conditions?  I was 
> > thinking that might be a way to improve mileage say under highway driving 
> > conditions.  My reasoning is this:  Adding exhaust gas to the intake would 
> > dilute the A/F mixture, without changing the actual A/F ratio, since exhaust 
> > doesn't contain oxygen or fuel.  Thus reducing the amount of fuel sent to the 
> > engine, without the problems associated with a lean mixture.  comments anyone?
> 
> EGR displaces air, less air = lower volumetric efficiency = less power.
> SO you open the throttle up to achieve the power output that you had
> before introducing EGR and guess what, your airflow and consequently
> fuel flow are higher than they were before introducing EGR.  EGR ain't
> good for nothing cept reducing NOx emissions :).  Excess air (lean burn)
> on the other hand does have fuel economy benefits.
> 
> 
> -- 
> Jonathan R. Lusky                        lusky at knuth.mtsu.edu
> http://www.edge.net/~lusky/                 (615) 726-8700
> -------------------------------------   ------------------------------
> 68 Camaro Convertible - 350 / TH350  \_/ 80 Toyota Celica - 20R / 5spd
>