RPM independence

[Todd....!!]

Hello Howard,

your theory is TOTALLY GREAT and acceptable, and a system has alread
ybeen created, produced, and marketed, and it's gone over wiht a pretty
good fine tooth comb within on eof the laterChecvy Hi po mags dealing
with all of the diff types, makes, and brands of FI for just about any
type engine!

Will get the name of the mag, I know you already know about the mag,
just maybe not about the article(s) within this specific issue?

But the basic function of the type system I believe you are referring to
is based upon the use of formulas instead of tables... I think you are
right in line witht the way this REALLY advanced system is designed to
function!

Will post details later, (mag's at home)!

LATER!

Todd....!!

Howard Wilkinson wrote:
> 
> I have given more than a little thought to the possibility of an EFI
> system that operated completely independently of engine RPM.  The idea
> being that as the injectors are batch fired anyway, the timing is
> irrelevant so long as the injectors fire at engine RPM or more.
>     Such a system could be almost entirely MAF based.  The injectors
> would begin at a very short pulse width, and simply increase pulse
> rate up to a set pulse rate where width would be increased thereafter.
> Such a system could be operated based on mathematical formulae rather
> than on look up tables.  A simple equation based on ECT could modify
> the result for cold operation, and a TPS modifier would give
> accelerator pump effect.  Map should not be necessary as air density
> should directly effect MAF output.  An O2 loop would handle minor
> dicrepancies.
>     A lot of the complexity of the common EFI systems comes from the
> desire to fire the injectors once per revolution.  Because of RPM
> dependence, the MAP, MAF, & TPS outputs are meaningful only in the
> context of RPM.  Total fuel delivery per unit time is only directly
> related to MAF.... It is not closely related to RPM, Throttle
> Position, or Vacuum individually as it is to MAF.  The MAF tells us
> how much fuel we must deliver per unit time, but the system must then
> work out the pulse rate based on RPM, and pulse width for that rate to
> achieve the desired delivery per unit time.
>     If we know that x amount of fuel is delivered at Y pulse width per
> pulse, then it becomes a simple matter to determine how many pulses
> per unit time are required to deliver that amount of fuel.  At some
> point pulse rate reaches a max practical limit, and at that point
> pulse rate can become constant, and pulse width may be modified above
> that point to control fuel delivery.  The fewer factors you are
> changing the simple the program becomes.
>     Perhaps this is a simple minded vew of the process, but then I'm a
> simple minded sort of guy.... I am of the "KISS" school of thought.
>                                 H.W.