VE tables

[Ward]

On Wed, 19 May 1999 21:29:13 -0400, Bruce Plecan wrote:

> 
> > When this thread started I was going to reply exactly as
> > stated below. This is certainly the theoretical answer. Last
> > night I even spent 2 hours adding the 4 VE vs load vs RPM
> > tables  to my LT1 editor.
> > During my two hours of thought on implementing the tables I
> > began to question the logic of this answer. VE is certainly
> > the % Volumetric efficiency, and we would need to change it
> > for items like Cam changes or porting that would effect the
> > VE. The problem I have is that we also have a MAF on these
> > engines. We therefore have two independent measures of Air
> > Flow. Which one does What?? In a Speed Density or MAP based
> > system VE would be the only answer, but in a MAF system how
> > are these two independent figures used?
> > Ken
> 
> Independent?.   I don't know if I'd say that.  They both are differnent
way
> of calculating the same thing, appropriate fueling.  On some applications
> some of the scan tools, display MAP+MAF numbers for a application that
only
> runs one, of them.  I forget the application off hand, but was some of
the
> 1227730 applications.
> Grumpy
> 

I think you guys are assuming that all table get used, and/or are used all
the time. 

All of the later ECM/PCM's have multiple mode operation.

For example if you cut the wireson a o2 senosr for say a 95 C/K truck you
now have a leaded fuel export truck ready to the far east. 

furter examination will show extensive afr tables that would not be
appropriate for nomal closed loop operation.


At to VE Vs MAF they are redundent. VE is used to caclate air flow in
grams/sec.

MAF measures it directly and applies fuel at the rate of 1 gram for every
14.7 grams of air. 

Ward.





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