Now let's suppose some stuff:
Suppose your intake runners were a little longer than they are.
Suppose you have a readout of intake temp.
Suppose you have injectors at both ends of the runners, and that the total fuel
flow through the injectors of a runner can be adjusted to inject all at the
block or all at the throttle body or anything between those extremes.
Suppose you got DIE at some intake temp, say 30 F at 5500 rpm (injecting at the
block only). That's a data point. At some other intake temp, you
will get DIE at some other rpm. Now you have a chart.
Now, when you want to take off, and you anticipate
your TO rpm to be 5500 you know you need 30 F intake temp. But on turn up
it's actually 80 F (injecting at the block). So you adjust the knob to
inject just enough fuel at the top of the runner to lower the temp to 35F and
viola' your rpm jumps, you have DIE and life is good. Climbing to
altitude, it's cooler so you have to bias a little more to the top of the
runner to maintain DIE. You throttle back to cruise at 5000 rpm.
You need to bias more toward the TB to bring the DIE rpm down to 5000 which
occurs at 15 F. And so forth
You get my drift. With a chart of rpm v. Tr you
know what temps you need for DIE at TO, climb and cruise. You know how
much you can reduce intake temp by going to block only injection (highest temp)
to TB only injection (lowest temp). You pick your envelope and build your
runners to fit. Then, even though the OAT changes and rpm changes (a
little) you can adjust intake temp to get DIE at the rpm and OAT you are at.
The key of course (more better we call it "detail
devil") is coming up with a way to bias fuel injected through each the two
injectors while maintaining the sum of the quantities injected at that needed
for proper combustion. That's one hell of a devil, but not nearly as
difficult as the original devising of a system that that figures out how much
fuel to inject and then delivers it. I would guess at this point that it
would be easier to adjust intake Temperature than intake Length. Tracy,
you listening??
Different folks desiring different flight regimes
would need runner lengths that bracketed the temps and rpm's they expected to
be operating at.
Just a theory ... Jim S.
Pretty cool theory, Jim. The stock Mazda injectors for turbo
engines have enough flow so either set could handle max power for a NA engine. And
the turbo guys don’t need DIE anyway. Modeling an override to
modulate pulse width to allocate fuel shouldn’t be that tough if you know
what the curve looks like.
Al
Al