More silly ideas-MAP2

[Bruce Plecan]

Yes, there is code for a baro calculation, near WOT.
But, it isn't a direct reading, which is what I'm after.
The display on the scan tool is 98 K/Pa, so whatever it's doing is fine for
gm but not for ultimate performance.   On the 747 is also, a rather crude,
setup up since it just ignores IAT/MAT.
  For bracket racing what I have is great, but I ain't bracket racing.
Bruce
  CSH, HQ will be closing for a least a few days starting 6/7/99.
If you think a plane fare is expensive, buy one with O2 for a nasal cannula.
You can't take your own tank, so you have to buy the O2 from them....

| Seems to me I've seen code where the MAP is read at WOT for get a new Baro
| reading. In fact doesn't the 747 have something in there about this?
|
| Is this right Mr. Fenske?
|
| Terry
| -----Original Message-----
| From: Matt S Bower <m.s.bower at cummins.com>
| To: gmecm at efi332.eng.ohio-state.edu <gmecm at efi332.eng.ohio-state.edu>
| Date: Friday, June 04, 1999 10:05 AM
| Subject: Re: More silly ideas-MAP2
|
|
| >
| >
| >Jeff M wrote:
| >>
| >> Bruce wrote:
| >>
| >> >In theory.  when you have Air Densities of 96% to 101% and the
| >> >scanner shows the engine is at 98 K/Pa under both sets of conditions
| then
| >> >there is a fly in the ointment.
| >>
| >> MAP gives you pressure and BARO readings (one in the sensed same), and
| >> density is calculated by adding air temperature computations via a MAT
| >> sensor (aside from the changes humidity does to the equation, but no RH
| >> sensors in GM vehicles yet ;-).
| >>
| >> To back up a bit, is not Barometric Pressure the measure of air
pressure
| >> relative to being at different altitudes and in varying climatic
| conditions?
| >> Then when the engine is exposed to these varying outside pressures, it
| will
| >> experience different cylinder filling (raw VE tables would not
compensate
| >> for this fully) while running.  And since warmer air is less dense (and
| the
| >> reverse as well), MAT needs to be added to the equation so (near) true
| air
| >> measuring can be performed.  So your fly has definitely landed but I
| >> wonder if there is a need to compensate for this as it is already done
on
| >> better designed cars/computers.  MAP is used to measure barometric
| readings
| >> at start up  on many GM vehicles and as an example, the Syclone/Typhoon
| use
| >> the MAP to show on my scanner (Diacom Plus) Barometric Pressure,
Manifold
| >> Absolute Pressure and Boost Pressure, all supplied via the one MAP
| sensor.
| >> Maybe your program (vehicle?) does not do this BARO check and
associated
| >> compensation and if so then I would suggest extracting the computation
| used
| >> by the Sy/Tys (or others) to be incorporated into your vehicle's
computer
| >> program to get you what you want.
| >
| >I think you missed the point on this one.  He does have the baro check
| >but he wants a way for it to continously read baro, not just at start
| >up.  He wants to make the system more sensative, in a sense, to changes
| >to be more accurate and try to make it self adjusting to changes is
| >altitude or the such while he's at it.
| >
| >
| > Another note on GM MAP sensors, they come
| >> in many ranges depending on application (stay with me here) and not
just
| 1
| >> bar, 2 bar and 3 bar.  GM has found (as it gets it together) that the
| >> reality of there being more than 1 bar of pressure at altitudes below
see
| >> level had a more dramatic effect on some vehicles than others so, GM
has
| 1.1
| >> and 1.2 and 1.25....... "1 bar" MAP sensors.
| >>
| >> More FYI:                                            multiply by
| >> Bars to Atmospheres                           0.9869233
| >> Bars to Inches Mercury                      29.529983
| >> Bars to Inches of Water                    401.48716
| >> Bars to Kilograms per sq centimeter     1.0197162
| >> Bars to Kilopascals                           100.00 (exact)
| >> Bars to Psi                                         14.503774
| >>
| >> >Weither do to filtering,  the design of the sensor, or pulsation
| >> characteristics, that the >sensor is reading something is wrong.
Without
| >> an emission lab to do the research >something needs done to compensate
| for
| >> it.   "My" baro/map idea isn't perfect, but it's a >whole lot better
| than,
| >> being in error all the time, IMHO.....
| >> >Grumpy
| >>
| >> You are right about being better, and that is the challenge we all do
| enjoy.
| >>
| >> Jeff Middaugh
| >> tystorm at email.msn.com
| >
|