Ok, one more time for us slow
folks. I understand that the EC2 calculations some "adjustment"
to the fuel requirement for each intake cycle. Since the intake cycle
is certainly tied to rpm in so far that the rpm determines the number
of intake events per unit time. I think I follow that each
intake cycle can be different as far as fuel requirement.
I had assumed that the fuel injection adjusment is primarily
based on the manifold pressure it senses. In otherwords, if the
Ec2 senses 17" Hg manifold pressure at a specific intake manfiold
air temp it calculates X milleseconds of injection time. I had
assumed that this amount of injection time would be the same
whether 17" at 3000 rpm or 17" at 5000 rpm but that since the
injector fires more times/sec at 5000 rpm than 3000 rpm there would be
more fuel injected. In otherwords, I had assumed that
since the EC2 does its calculation for each cycle, it didn't
know(orcare) whether the cydle was happening at 3000 rpm or 5000 rpm
only what the manifold pressure was at each rpm.
Since my assumption is apparently
incorrect, then over a beer, you need to explain it to me one more
time how the RPM is a factor in the computation of fuel injection
time.
I strongly suspected that Ve
wasn't really a factor for the reasons you stated, too bad
{:>)
Ed Anderson
I think semantics are confusing
both of us (or me at least : ). If we look at it in terms
of a single intake cycle, rpm does not figure into the equation. If
you look at it in terms of CC per minute or gallons per hour, it
does. However, in the latest version of the
software (which Rusty has), rpm does have an effect in that a
different MAP table is used for high and low RPM ranges.
Tracy (who would never
accuse Ed of being slow ! )
OK, Tracy, I agree about the semantics and the
two points of reference. Within terms of a single intake
cycle rpm does not directly figure into the fuel injection time
calculation. However, it is certainly a factor in terms of
CC/Minute as there are more intake cycles at 5000 rpm than 3000
rpm. So when I stated earlier that RPM was not a computation
factor in determining injector pulse width time, I did not mean
it was not a factor in determining how many CC/Gallons of fuel flow
were consumed. So if you consider that total injection time (and
therefore total fuel flow) is a product of injection time computed
(based on manifold pressure) AND number of times that injection
cycle is trigger per unit time (RPM), then I think we are on the same
sheet of music. RPM IS a factor in determining fuel flow, just
not in calculating injector pulse width. (I think).
Thanks for the explanation (again
{:>)).
Ed Anderson