[Diy_efi] EMS Fueling Calculations

[Brian Dessent]

Mark wrote:

> I'll take a shot at the first question. P*V=n*R(bar)*T is a form of the
> ideal gas law. Another easier way to write it (and less work) is:
> 
> P*V=R*T, where

And a few other points:

- There are a number of ways of representing the equation, depending on
what you're looking for.

- The important thing is that it relates four things: Pressure, Volume,
Temperature, and Mass.  If you know any three, you can find the fourth. 
Or, if you know that two are fixed, you can find out how the remaining
two are related, etc.

- All the units in the equation are absolute.  For temperature, you have
to use Kelvin or Rankin.  For pressure, add atmospheric to gauge to get
absolute.  Watch the units, preferably use all SI.  The value of the
constant (R) will depend on what units you've chosen.

- Air is close enough to "ideal" to make this equation useful under most
conditions.

- ECU calculations are all about finding a baseline value and then
adding or subtracting a whole slew of corrections depending on the
particular conditions.

Brian

_______________________________________________
Diy_efi mailing list
Diy_efi at diy-efi.org
http://www.diy-efi.org/mailman/listinfo/diy_efi