Use of MAP in FI calcs

Len Sabatine sabatine at epix.net
Sat Sep 9 13:50:34 GMT 2000


    Glad you pointed  out this material  Bruce !! Built in weather 
compensations
  for emissions or just plain old driveability " are good things GM has 
built in to the
   controllers . There's some forgiveness built in as well , since weather 
is in a
  constant state of flux. Weather wise , Intake and Exhaust VE are most 
certainly
  effected in unison, it's all about filling those " Lungs" . Everything 
breathes easier
on those perfect weather days, and not so well on those terrible weather days.
  BARO , CTS , IAT, MAP, EGR , TPS ,  VE are all tied together , OR how do 
we attempt
to ADAPT to constant change of the  elements which effect vehicle systems ?
How different are the conditions in Death Valley compared to the South Pole ?
It's ALL very relevant !!
   Len

>Bruce Plecan wrote:
> > How about as it applies to EGR, and when your working with a couple
>million
> > cars, and the EPA sometimes close ain't good enough
>Yes, BARO is used there.  BARO is also sometimes used in the coolant
>temperature advance adjustments.  Some ECMs index by CTS and MAP, some
>by CTS and (BARO-MAP), and some can do either.
> >  I would think that a few kPa variation in baro would have minimal effect
>on
> > scavenging.
>Here's the relevant table for a Fiero 2.8.  The table's value gets
>multiplied into the "regular" VE value.  It is also used in the EGR
>calculations.
>ExhaustVETable  DC.B 96,32,9    ;<487> Exhaust volumetric efficiency
>         ;         8  12  16  20  24  28  32  36  40 '00 RPM
>         DC.B    141,141,141,138,134,130,128,128,128 ;75 KPa BAP
>         DC.B    134,134,136,134,130,128,128,128,128 ;85
>         DC.B    128,128,128,128,128,128,128,128,128 ;95
>         DC.B    128,128,128,128,128,128,128,128,128 ;105
>
>Makes absolute sense to me.
>They're using it at what apprears to be the top end on the EPA test cycle,
>where still in closed loop and before PE.  I'd be interested in using some
>thing similiar table wise from 2K to 6K rpm,
>then 90-95-100-105 and one for timing, both while in PE..
>     Bruce
>
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