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OK Walter, I'll bite.
It appears that the fuel "fog" transparency is lowest too early in the
cycle. The fog indicates the presence of liquid droplets, similar to
what happens over the wing of a fighter in a high alpha turn on a humid
day. I would think the fuel of a homogeneous mixture would form at the
point of highest pressure drop (temperature drop), which should happen
closer to maximum piston velocity (mid stroke). Also, there appears to
be fuel droplets striking the back of the valve late in the intake
cycle. You could be more certain if the "deg CA" (degrees crank angle)
indicator wasn't pixelated.
I assume that when you say "injection" you are referring to typical
aircraft injection, which has a continuos fuel flow rather than timed
injection. With continuos injection a load of fuel builds in the
induction system during 3 of the 4 cycles. When the intake opens, a
super rich mixture is followed by a very lean mixture and lots of
slobbering.
With carbureted and timed injection the charge is more homogeneous.
My vote is for continuos or PWM injection.
It is interesting that the first few frames show the piston at near
TDC but there is no overlap. Also, there is fuel fog the moment the
intake opens, indicating that exhaust scavenging or induction tuning or
supercharging is taking place and the cylinder pressure is below the
manifold pressure. It is possible that apparent fuel mixture bias is
is due to the transition of this effect to piston induced pressure drop
but the fuel slobbering at the end of the stroke still points to C.I..
Do you know the circumstances of this engine?
Cool video, BTW. Thanks Rob!
Regards
Brent Regan
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